BioEnergy Lists: Improved Biomass Cooking Stoves

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January 2003 Biomass Cooking Stoves Archive

For more messages see our 1996-2004 Biomass Stoves Discussion List Archives.

From geletukha at BIOMASS.KIEV.UA Sat Feb 1 01:40:28 2003
From: geletukha at BIOMASS.KIEV.UA (Georgiy Geletukha)
Date: Tue Aug 10 18:30:11 2004
Subject: Proceedings of the First International Ukrainian Conference
on Biomass for Energy
Message-ID: <SAT.1.FEB.2003.094028.0300.GELETUKHA@BIOMASS.KIEV.UA>

Dear Tom and Stoves_list members,

Yes, the content of CD is published on our WEB site: www.biomass.kiev.ua

But in any case I'd like to send one free copy of CD to
ListServ. Please inform me post address for this.

Best regards,

Georgiy
-------------------------------------------------
From: Dr. Georgiy Geletukha
Director, Scientific Engineering Centre "Biomass".

P.O. Box 964, Kiev-67, 03067, UKRAINE
Tel: +380 44 456 9462, 441 7378
Fax: +380 44 484 8151
E-mail: geletukha@biomass.kiev.ua
http://www.biomass.kiev.ua

----- Original Message -----
From: "Tom Miles" <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, February 01, 2003 3:39 AM
Subject: Re: Proceedings of the First International Ukrainian Conference on
Biomass for Energy

> Georgiy,
>
> Is the table of contents of the CD or the list of papers in the conference
posted on
> your conference website?
>
> Thanks
>
> Tom
>
> ----- Original Message -----
> From: "Kevin Chisholm" <kchisholm@CA.INTER.NET>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Friday, January 31, 2003 10:57 AM
> Subject: Re: Proceedings of the First International Ukrainian Conference
on Biomass
> for Energy
>
>
> Dear Paul
> ----- Original Message -----
> From: "Paul S. Anderson" <psanders@ILSTU.EDU>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Friday, January 31, 2003 2:45 PM
> Subject: Re: Proceedings of the First International Ukrainian Conference
on
> Biomass for Energy
>
>
> > Georgiy and other Stovers,
> >
> > It would be nice if someone who has this CD could post to the Stoves
List
> > Serve for the others to see the titles, etc of any items especially of
> > interest to the Stoves people.
>
> That would sort of be against copyright laws, and would deprive the
> Organizers of the opportunity of defraying their Conference costs wouldn't
> it?
>
> Wouldn't it be better to support them, and purchase a copy?
>
> Kindest regards,
>
> Kevin
> >
> > Paul
> >
> > At 11:49 AM 1/30/03 +0300, Georgiy Geletukha wrote:
> > >Dear colleagues,
> > >
> > >Proceedings of the First International Ukrainian Conference on Biomass
> for
> > >Energy September 23-26, Kyiv are issued on a compact disk
> > >
> > >Proceedings of the First International Ukrainian Conference on Biomass
> for
> > >Energy (September 23-26, Kyiv) are issued on a compact disk. The
compact
> > >disk contains unique materials of the conference, which was attended by
> 180
> > >specialists including 17 from Newly Independent States and 27 from the
> USA
> > >and European countries (Austria, Denmark, Germany, Sweden and others).
> There
> > >are on the disk 85 full texts of presentations and 120 abstracts on
> > >technical, economic, ecological, legislative aspects of
biomass-to-energy
> > >technologies and also bioenergy development issues concerning Ukraine
and
> > >other countries. You can find also on the disk resolution of the
> conference,
> > >full list of participants with their contact information, published
> booklets
> > >and articles on bioenergy, conference photograph album and other useful
> > >information. The disk is done in English and Russian.
> > >
> > >
> > >One disk costs USD 40 or EUR 40
> > >
> > >To order the disk please apply at the following address:
> > >Institute of Engineering Thermophysics
> > >office 236, 2A, Zhelyabov str.
> > >03057, Kyiv, Ukraine
> > >tel: (+ 38 044) 441-7378, tel./fax: (+ 38 044) 456-9462
> > >e-mail: conference@biomass.kiev.ua
> > >web site: www.biomass.kiev.ua
> > >
> > >Best regards,
> > >
> > >Georgiy Geletukha
> > >-------------------------------------------------
> > >From: Dr. Georgiy Geletukha
> > >Director, Scientific Engineering Centre "Biomass".
> > >
> > >P.O. Box 964, Kiev-67, 03067, UKRAINE
> > >Tel: +380 44 456 9462, 441 7378
> > >Fax: +380 44 484 8151
> > >E-mail: geletukha@biomass.kiev.ua
> > >http://www.biomass.kiev.ua
> >
> > Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> > Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
> > Dept of Geography - Geology (Box 4400), Illinois State University
> > Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> > E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>

From lanny at ROMAN.NET Sat Feb 1 11:03:47 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:11 2004
Subject: Foods eaten in developing areas.
Message-ID: <SAT.1.FEB.2003.080347.0800.LANNY@ROMAN.NET>

Foods eaten in developing areas.

Since we are developing stoves I thought that it would be helpful to cook
some foods that would actually be eaten by people in developing areas.
I am familiar with some foods and cooking methods like:
Pot Cooking of: rice milled and brown, beans, stews.
Wok cooking of meats and vegetables.
Oven cooking of breads.

But I need cooking methods and receipts for:
Pot cooking of:
1- African corn mush? and relish? for the two pot stove.
Griddle cooking of:
2- Flat wheat bread - wheat flower, water, oil? salt?
3- Flat corn tortillas - corn flower or corn meal? water, lime? salt? oil?
4- Other griddle cooked foods.
5- Anything that I did not list.
Thanks Lanny

From hseaver at CYBERSHAMANIX.COM Sat Feb 1 09:50:44 2003
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:30:11 2004
Subject: news from ARTI
In-Reply-To: <000001c2c9fb$609be940$565841db@adkarvepn2.vsnl.net.in>
Message-ID: <SAT.1.FEB.2003.085044.0600.HSEAVER@CYBERSHAMANIX.COM>

Dr. Karve;
If I'm not mistaken, this sounds like the same stove/cooker you've mentioned
before. Is it possible to buy one of these and have it shipped to the US? I
recently bought some other small items from India, and the shipping wasn't
really all that much.

On Sat, Feb 01, 2003 at 08:54:31AM +0530, A.D. Karve wrote:
> Dear Tom,
> no, this is not the Laxmi stove. The one that I refered to is a stainless
> steel steam cooker, which we have named Sarai. It is a non-pressurised
> cooker, into which you put about 150 ml of water and then lower into it a
> wire cage, which holds three cookpots, one on top of another. The steam pot
> has a lid which is kept closed while the food is being cooked. The heat is
> provided by a charcoal burner, which is designed to hold just 100 g of
> charcoal or a single honeycomb briquette of 100 g. After the coal has caught
> fire, the steam pot containing the food to be cooked is placed on the stove.
> A hollow cylinder, also made of stainless steel, surrounds the entire
> assembly, including the stove. the gap between the steam pot and the
> stainless steel cylinder surrounding it is just 5 mm. The flue gases
> generated by the stove escape through this gap. In this way, the pot is
> heated on all sides, instead of just from the bottom. The boiling and
> evaporation test showed the efficiency of this gadget to be 70%. Beans, rice
> and vegetables of a family of 4 to 5 are cooked with just 100 g of charcoal
> briquettes. It takes between 45 minutes to an hour to cook the meal. At
> present we are advocating it for food that needs to be cooked. We have not
> tried roasting anything in this cooker.
> Yours A.D.Karve
> -----Original Message-----
> From: Tom Miles <tmiles@TRMILES.COM>
> To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
> Date: Saturday, February 01, 2003 7:34 AM
> Subject: Re: news from ARTI
>
>
> >Dr. Karve,
> >
> >Thank you for the news. Some questions:
> >
> >Is the stove and cooker you refer to the Laxmi stoves that we have posted
> on the
> >stoves website? www.trmiles.com/stoves Is there a place where we can link
> to a
> >picture or diagram and description of the stove and cooker or can you send
> me some
> >infomration to post on the website?
> >
> >Since the alkali in the grass and trash must concentrate mostly in the char
> during
> >charcoaling do you experience any slagging from burning the charcoal?
> >
> >Thanks
> >
> >Tom Miles
> >

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com

From tmiles at TRMILES.COM Sat Feb 1 12:58:49 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:11 2004
Subject: Foods eaten in developing areas.
Message-ID: <SAT.1.FEB.2003.125849.0500.TMILES@TRMILES.COM>

Lanny,

Good idea. I'll create a Foods section for cooking conditions on the Stoves
website at www.trmiles.com/stoves

Tom

From tmiles at TRMILES.COM Sat Feb 1 13:32:17 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:11 2004
Subject: Damon Ogle reports on refractory perlite/clay bricks
Message-ID: <SAT.1.FEB.2003.133217.0500.TMILES@TRMILES.COM>

On Wed, 29 Jan 2003 08:50:15 -0800, Dean Still <dstill@EPUD.NET> wrote:

>Dear Friends,
>
>After this message you'll find Damon's report on his most successful
>method of making insulative, refractory bricks using 85% perlite and 15%
>clay. I'm also sending STOVES a few small pictures of the six brick stove
>made from his recipe and photos of the homemade press he uses. Making six
>bricks that combine into a stand alone combustion chamber means that the
>insulating combustion chamber can be used in a Lorena type stove or serve
as
>a stove without a covering of mud.

I've posted this article with pictures as a pdf file on the Stoves webpage
at www.trmiles.com/stoves It should also be available at repp.org in a few
weeks.

See also the Rocket Stove Design Guide pdf (Aprovecho)

Ceramic Engineering objectives are to develop lightweight, strong/robust,
non-abrasive, spalling resistant, insulating refractory materials for
combustion chambers. Life of the rocket type combustion chamber seems to be
about 3 to 4 years. Abrasion has also been identified as from possible
spalling of the refractory, probably due to a combination of the
temperatures and fuel chemistry.

Can the experience of industrial ceramic engineers help here? I've worked
in the past with engineers at Coors, Colorado School of Mines and other
institutions. What about the experience with ceramic stoves by
ARECOP/RWEDP, GTZ/ProBEC or others? I suspect there is some ceramic
discussion in the publications, proceedings or dossiers at www.arecop.org.

Tom

From andrew.heggie at DTN.NTL.COM Sun Feb 2 15:23:38 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:11 2004
Subject: Damon Ogle reports on refractory perlite/clay bricks
In-Reply-To: <004a01c2c7b6$8764ca20$f41e6c0c@default>
Message-ID: <SUN.2.FEB.2003.202338.0000.>

On Wed, 29 Jan 2003 08:50:15 -0800, Dean Still wrote:

>Dear Friends,
>
>After this message you'll find Damon's report on his most successful
>method of making insulative, refractory bricks using 85% perlite and 15%
>clay.

Dean

Thanks to you and Damon for this recipe, I shall definitely try it.

Thanks also to Tom and Damien for their hard work in re structuring
the list software, it looks good so far.

Congratulations to AD Karve and the help from shell.

It's good to hear from you all on stoves again.

AJH

From tombreed at ATTBI.COM Mon Feb 3 12:22:56 2003
From: tombreed at ATTBI.COM (Tom Reed)
Date: Tue Aug 10 18:30:11 2004
Subject: Foods eaten in developing areas.
Message-ID: <MON.3.FEB.2003.102256.0700.TOMBREED@ATTBI.COM>

Dear Lanny Henson and All:

We here at the Biomass Energy Foundation STOVEWORKS believe that improved
stoves requires a holistic approach. Every country (even, county sometimes
in the U.S.) has developed different cooking requirements depending on

Type of food prepared
Type of cooking equipment available
Type of manufacturing available
Type of sales and marketing
Religious restrictions on food and cooking
Perceptions (true and false) about the nature of cooking
And lots of ETC.

Ignoring these many points was one reason that we made such slow progress in
stove deployment in the 1980s in spite of lots of time and money and good
will spent.

SO, while we are considering recipes for specific dishes, I would also
welcome comments on the other points above from our worldwide members. I
will try to collect all comments and store them in a HOLISTIC COOKING file
on my Email. When it is full, maybe I will write a draft of a short essay
for all to inspect and then we could write the first paper originating at
the new STOVE site.

Yours truly, TOM REED BEF STOVEWORKS
Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
----- Original Message -----
From: "Lanny Henson" <lanny@ROMAN.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, February 01, 2003 9:03 AM
Subject: Foods eaten in developing areas.

> Foods eaten in developing areas.
>
> Since we are developing stoves I thought that it would be helpful to cook
> some foods that would actually be eaten by people in developing areas.
> I am familiar with some foods and cooking methods like:
> Pot Cooking of: rice milled and brown, beans, stews.
> Wok cooking of meats and vegetables.
> Oven cooking of breads.
>
> But I need cooking methods and receipts for:
> Pot cooking of:
> 1- African corn mush? and relish? for the two pot stove.
> Griddle cooking of:
> 2- Flat wheat bread - wheat flower, water, oil? salt?
> 3- Flat corn tortillas - corn flower or corn meal? water, lime? salt? oil?
> 4- Other griddle cooked foods.
> 5- Anything that I did not list.
> Thanks Lanny
>

From psanders at ILSTU.EDU Tue Feb 4 00:01:39 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:11 2004
Subject: Burning of excessive CO
Message-ID: <MON.3.FEB.2003.230139.0600.PSANDERS@ILSTU.EDU>

Stovers,

I seek information on what is needed to be able to combust the CO that is
produced by fires. When CO is produced in abundance (poor fire), how can
we "capture it and burn it"?

I recently saw brochures on two wood-burning stoves (for heating homes in
America) where each had a method of additional burning:

One (Harman Exception Wood Stove) had an "afterburner" down the back side
of the heavy, metal stove. Brochure says: "Unburned gases pass into the
afterburner chamber, where they are mixed with air at very high
temperatures." Brochure has a cross-section drawing, (looks like about 25
cm or 10 inches of downward-moving gases in a chamber with baffles to
promote mixing or increase surface area. But I did not find that drawing
on the company's website.

A photo-picture at http://www.harmanstoves.com/images/TL200a.JPG shows
the stove but not the afterburner that is on the back side of the body of
the stove.

The other company (Lopi Woodstoves) has a different method. A stove is
shown at http://www.lopistoves.com/product.asp?dept_id=4&sku=33 but
the website does not show the cross-section diagram available in the
printed brochure. This stove (after start up) has a lever to direct some
(unstated percentage) of the potential flue-gases back into the top of the
main combustion chamber via some pipes that also introduce some additional
air (seems to be preheated). In the functioning stoves you can see the
flames (about an inch long) in the chamber after leaving the tubes. No
indication of fans / forced air.

At least these two companies take potential flue gases and get some
additional burning out of them. That means more heat inside the stove and
less CO (and other potentially polluting gases, etc) going up the chimney.

I have noticed that CO pours out of a charcoal fire. We should be able to
burn it.

So my question is, what are the key elements to successful burning of CO (+
other)? Issues could be:

Concentration of the CO
Temperature of the CO
Temperature of whatever air enters (perhaps cooling too much the CO that
could burn if the air was hot??)

Eager to learn,

Paul

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Tue Feb 4 00:15:50 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:11 2004
Subject: Fw: charcoal from bamboo and activated carbon
In-Reply-To: <03d401c2c98d$b4954b90$6701a8c0@tommain>
Message-ID: <MON.3.FEB.2003.231550.0600.PSANDERS@ILSTU.EDU>

Dear Mr. Ganesh Agarwal and Stovers,

I and others could be interested in the size of operation that you are
wanting to conduct to make charcoal. And that will be influenced by the
amounts of bamboo that you have available on a sustainable basis.

I am mainly interested in SMALL production units operated by MANY people,
with use of the created gases for cooking or heating or small
business. The net result is still charcoal, but it is a by-product of the
gasification (pyrolysis stage only) of the bamboo. I and others would be
happy to assist you along those lines.

Notice that I made no reference to "activated" charcoal. What is its
importance to your project?

Since you are not on the Stoves List, you cannot send to the List. But if
you reply to me, I will forward what might be appropriate for the List members.

Paul

At 05:03 PM 1/31/03 -0800, you wrote:
>Stovers,
>
>This message was posted to the list during our "holiday". It may be of
>interest to
>the charcoalers in the group.
>
>Tom
>
>----- Original Message -----
>From: "Ganesh Kr. Agarwal" <patkaicoal@rediffmail.com>
>Sent: Wednesday, January 01, 2003 5:03 AM
>
>
>Sub: Charcoal from Bamboo and Activated Carbon.
>
>Dear Sir,
>
>With reference to the above subject, we would like to inform you
>that we are interested in setting up a plant to manufacture
>Charcoal from Bamboo and Activated Carbon in Assam in INDIA. If
>you can provide us the technology/know-how to manufacture the
>same. Please do write to us along with details of the project and
>your term and condition.
>
>Looking for an early reply.
>
>With best regards
>Ganesh Agarwal
>Tirupati Cottage Industry
>S.B.I. Building,
>S.R.Lohia Road
>Tinsukia-786125
>Assam, INDIA.
>
>Tel: 0374-2338023

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From adkarve at PN2.VSNL.NET.IN Tue Feb 4 08:34:39 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:11 2004
Subject: Foods eaten in developing areas.
Message-ID: <TUE.4.FEB.2003.190439.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Tom,
when we tried to disseminate our biomass burning stoves having higher
efficiency and low emissions, the housewives always complained about our
stoves citing either the one or the other of the reasons listed by you. Then
came Kerosene and LPG. The user friendliness of both these fuels is so
great, that housewives in India changed their cooking habits. For instance,
the standard unleavened bread made in our state has a diameter of about 40
to 50 cm. To bake this bread uniformly, one requires a very large griddle,
an equally large pothole, and a big roaring fire. But the same housewife
meekly starts making bread having a smaller diameter when she switched from
the wood burning stove to kerosene or LPG.
So, I think that if we could give to the housewives a stove and fuel
combination that produces a blue flame, that ignites instantaneously and in
which the flame intensity can be easily manipulated, she would forget all
her objections about the stove not being suitable for preparing her ethnic
food. At t least at the present moment, biogas is the only renewable
alternative that is available in India, but this technology failed because
although the fuel and the cooking device satisfied all the criteria
mentioned above, the bother of producing the gas is too much for the
housewife.
We are trying to develop a biogas technology, which would be almost as user
friendly as LPG and yet cheaper than LPG. The preliminary experiments are
highly encouraging, but our present digester model is very small, producing
just about 50litres of biogas. We shall have to scale it up to produce at
least 10 times as much biogas.
Yours A.D.Karve
-----Original Message-----
From: Tom Reed <tombreed@attbi.com>
To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
Date: Monday, February 03, 2003 11:06 PM
Subject: Re: Foods eaten in developing areas.

>Dear Lanny Henson and All:
>
>We here at the Biomass Energy Foundation STOVEWORKS believe that improved
>stoves requires a holistic approach. Every country (even, county sometimes
>in the U.S.) has developed different cooking requirements depending on
>
>Type of food prepared
>Type of cooking equipment available
>Type of manufacturing available
>Type of sales and marketing
>Religious restrictions on food and cooking
>Perceptions (true and false) about the nature of cooking
>And lots of ETC.
>
>Ignoring these many points was one reason that we made such slow progress
in
>stove deployment in the 1980s in spite of lots of time and money and good
>will spent.
>
>SO, while we are considering recipes for specific dishes, I would also
>welcome comments on the other points above from our worldwide members. I
>will try to collect all comments and store them in a HOLISTIC COOKING file
>on my Email. When it is full, maybe I will write a draft of a short essay
>for all to inspect and then we could write the first paper originating at
>the new STOVE site.
>
>Yours truly, TOM REED BEF STOVEWORKS
>Dr. Thomas B. Reed
>1810 Smith Rd., Golden, CO 80401
>tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
>----- Original Message -----
>From: "Lanny Henson" <lanny@ROMAN.NET>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Saturday, February 01, 2003 9:03 AM
>Subject: Foods eaten in developing areas.
>
>
>> Foods eaten in developing areas.
>>
>> Since we are developing stoves I thought that it would be helpful to cook
>> some foods that would actually be eaten by people in developing areas.
>> I am familiar with some foods and cooking methods like:
>> Pot Cooking of: rice milled and brown, beans, stews.
>> Wok cooking of meats and vegetables.
>> Oven cooking of breads.
>>
>> But I need cooking methods and receipts for:
>> Pot cooking of:
>> 1- African corn mush? and relish? for the two pot stove.
>> Griddle cooking of:
>> 2- Flat wheat bread - wheat flower, water, oil? salt?
>> 3- Flat corn tortillas - corn flower or corn meal? water, lime? salt?
oil?
>> 4- Other griddle cooked foods.
>> 5- Anything that I did not list.
>> Thanks Lanny
>>
>

From tmiles at TRMILES.COM Tue Feb 4 12:28:52 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:11 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <TUE.4.FEB.2003.092852.0800.TMILES@TRMILES.COM>

Stovers,

Christa Roth and Christoph Messinger, Integrated Food Security Programme Mulanje, Malawi and Grant Ballard Tremeer, HEDON Household Energy Network, have posted a page of pictures of different types of energy saving stoves in Southern Malawi on the Hedon web site at http://ecoharmony.net/hedon/howto.php

Grant has also posted two picture guides from IFSP
a.. How to Make a Food Warmer / Fireless Cooker - a picture guide
a.. How to Build a Portable Clay Stove - a picture guide

Thanks Christa and Grant for posting this useful information.

Tom Miles

From psanders at ILSTU.EDU Tue Feb 4 13:59:24 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:11 2004
Subject: Chinese gasifier stove
Message-ID: <TUE.4.FEB.2003.125924.0600.PSANDERS@ILSTU.EDU>

Kirk Smith and other Stovers,

The "Chinese Gasifier Stove" shown
at http://www.trmiles.com/stoves/ (scroll down a ways to see it) is
not fully described. The picture seems cut off and that there could be
lower section to the stove.

I am trying to determine the TYPE of gasifier that it is. Most
specifically, I am comparing it with Tom Reed IDD stove (of which my Juntos
stove is an offspring).

If Kirk Smith (who provided the picture from China) is not on this general
Stoves List Serve, would someone (Tom Miles??) please relay this message to
him. I doubt if anyone else could answer the question unless you can
provide a contact to the people in China who make or promote that stove.

Paul

 

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Tue Feb 4 15:47:17 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:11 2004
Subject: Fw: charcoal from bamboo and activated carbon
In-Reply-To: <20030204135836.19798.qmail@webmail8.rediffmail.com>
Message-ID: <TUE.4.FEB.2003.144717.0600.PSANDERS@ILSTU.EDU>

Hello (with info for Stovers who might be interested) and forwarded to the
Gasification List Serve.

I do not know much about activated charcoal making. (which I believe is a
process done separately after the charcoal is available, but correct me if
I am wrong.) But please tell me what percentage of total charcoal will be
for that purification work of activated charcoal?

Otherwise, it seems that you want to create electricity. And you have
plenty of bamboo. If that is the case, why first make charcoal (loosing
much of the heat energy)? Start with the bamboo and go to the electricity
production without ever touching the charcoal.

Your situation could be of interest to the companies that product
commercial-sized gasifiers, so I am forwarding this message (and yours) to
the Gasification List Serve just this one time. Those people can contact
you directly.

I return to the issue of small-scale production of heat and of charcoal,
using the IDD gasification techniques pioneered by Dr. Tom Reed. We have
never determined how large one of these IDD gasifiers could be, but our
interests have NOT been directed toward large units that drive electricity
generators.

For me to continue with any assistance, I would need to know if very small
sized "stoves" that produce charcoal from bamboo would be of interest to
you. If yes, and even if you have only a very small budget, I and others
could possibly assist you. (We do not have funding sources available to
us, but could assist you to get funding if you decided to try our
small-scale approach to charcoal making (with heat generation for household
stoves or small businesses).)

To see what I am mentioning, please go
to http://www.trmiles.com/stoves/ and see the photos listed with my
name Paul S. Anderson and ALSO the more recent photos at the location
of the ETHOS
Conference http://www.trmiles.com/stoves/Ethos/Ethosjan03.html

Unless others on the Stoves list serve speak up of their interest, my
further conversations with you will be direct and without copies to the
list serve.

I look forward to hearing from you.

Paul

At 01:58 PM 2/4/03 +0000, Ganesh Kr. Agarwal wrote:
>Dear Sir, Thanks for showing interest. We have received your mail and
>noted the contents their in. We would like to inform you that in INDIA
>Assam and its surrounding has plenty of bamboos. There for we don't see
>any difficulty in procuring the same. Subject to cost/profitability
>factor. The average weight of bamboo is given below as required by you. We
>would like to inform you that we are very much interested in setting up
>the Bamboo Charcoal and Vinegar plant. This will be one part and after
>successfully implementation we would proceed further in Activated carbon.
>As Activated Carbon made from Bamboo Charcoal is much superior in quality
>that any other material. And there is good demand for Activated Carbon
>made from Bamboo. We would also like to inform you that we have bamboo
>Stick plant for Incense Stick, which generated lots of dust, can the same
>be utilized for making Charcoal and Activated Carbon. Lower Part of
>Bamboo - 16 K.G Length 16 Ft. Upper Part of
>Bamboo - 16 K.G Length 24 Ft. Full length of
>Bamboo - 27 L.G Length 38 Ft.
>Knots - 10 pcs per kg All were cut and
>thrown on open place for 15 days We hereby request you to please send us
>some details like realization of Bamboo Charcoal, and realization of
>Activated Carbon from bamboo Charcoal along with plant capacity and brief
>details about how you want to implement the same and produce Electricity
>and how much Mega Watt plant can be established. Along with cost details.
>Looking for an early reply. Thanking you Yours truly, For Tirupati Cottage
>Industry Ganesh Agarwal

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Tue Feb 4 15:53:59 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:11 2004
Subject: Chinese gasifier stove
In-Reply-To: <008201c2cc8b$6b638580$329a0a40@kevin>
Message-ID: <TUE.4.FEB.2003.145359.0600.PSANDERS@ILSTU.EDU>

Kevin, thanks, but I think that is a different stove. Does not look like
the posted picture, and the pot-position is very different. Can you or
anyone confirm (pro or con) if the stove in Smith's picture is of the same
type as the one cited below by Kevin.

Paul

At 03:44 PM 2/4/03 -0400, Kevin Chisholm wrote:
>Dear Paul
>
>The following link takes you to a site that carries a gasifier stove system:
>
>http://www.chinadepot.com/stoveberlin.html
>
>It is intended to operate on agricultural waste... straw... but it would
>probably work well on wood chips also.
>
>Regards,
>
>Kevin
>----- Original Message -----
>From: "Paul S. Anderson" <psanders@ILSTU.EDU>
>To: <GASIFICATION@LISTSERV.REPP.ORG>
>Sent: Tuesday, February 04, 2003 2:59 PM
>Subject: Chinese gasifier stove
>
>
> > Kirk Smith and other Stovers,
> >
> > The "Chinese Gasifier Stove" shown
> > at http://www.trmiles.com/stoves/ (scroll down a ways to see it)
>is
> > not fully described. The picture seems cut off and that there could be
> > lower section to the stove.
> >
> > I am trying to determine the TYPE of gasifier that it is. Most
> > specifically, I am comparing it with Tom Reed IDD stove (of which my
>Juntos
> > stove is an offspring).
> >
> > If Kirk Smith (who provided the picture from China) is not on this general
> > Stoves List Serve, would someone (Tom Miles??) please relay this message
>to
> > him. I doubt if anyone else could answer the question unless you can
> > provide a contact to the people in China who make or promote that stove.
> >
> > Paul
> >
> >
> >
> >
> > Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> > Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
> > Dept of Geography - Geology (Box 4400), Illinois State University
> > Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> > E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Tue Feb 4 16:26:30 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:11 2004
Subject: metals testing
In-Reply-To: <OFE97ABBF9.F2B17170-ON85256CC3.006D9316@udayton.edu>
Message-ID: <TUE.4.FEB.2003.152630.0600.PSANDERS@ILSTU.EDU>

Dear Margie,

I am forwarding this to the Stoves List serve and to the ETHOS
list. Everyone is invited to make comments.

I have no failed stoves (yet).

A Tuesday PM class is possible for me (EARLY drive all of Tues AM.) How
long is the class period? Date to be discussed. What are your class
plans in Feb?

Must close. Keep in contact.

Paul

At 03:08 PM 2/4/03 -0500, Margaret.Pinnell@notes.udayton.edu wrote:
>One lab section of 12 students have decided to take on the metals testing
>for the stoves.
>
>The students plan to test the stainless steel, a mild steel and the 3CR12.
>
>Currently they plan to conduct tests on as-received material and on
>material subjected to thermal cycling (700 C?)
>
>
>The students will be conducting tensile tests (in accordance with ASTM
>standard E8), hardness tests and abrasion tests. Students will also be
>doing metallographic inspection of the materials.
>
>They have come up with some great questions. Can you please answer these?
>
>1. Are there any other tests that you would like to have conducted?
>Compression tests on thin samples is difficult, that is why compression
>testing has not been included in teh test matrix.
>
>2. The students are currently looking into commercially available
>thicknesses of these three materials. Does it matter what thickness of
>material the students test as long as all three materials have the same
>thickness? Originally you requested 3 mm or 3.5 mm.
>
>3. The students would like more information on how these materials are
>being used and what specific material questions need to be addressed. Can
>you provides some more detailed information (they have a copy of the
>Juntos Stove handout written by Paul Anderson)?
>
>4. Any pictures of stoves and pictures of failed stoves would be greatly
>appreciated. If you have failed parts from the stove and could send these
>to us, that would be greatly appreciated as well.
>
>5. Paul, if you are still interested in coming to talk to my class, we
>meet on Tuesdays at 1:30. Let me know!
>
>Students are moving fast and furious on this and will have testing done,
>analysis completed and presentation prepared by the end of the semester or
>earlier (end of April). A quick response to these questions would be
>greatly appreciated. We have a great group this semester!!!
>
>God Bless,
>
>Margie
>
>Margaret F. Pinnell, Ph. D.
>Visiting Assistant Professor
>Department of Mechanical and Aerospace Engineering
>University of Dayton
>300 College Park
>Dayton, Ohio 45469-0210
>Phone: 937-229-3464
>Mobile: 937-750-6423

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From crispin at NEWDAWN.SZ Tue Feb 4 17:15:51 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:11 2004
Subject: metals testing
Message-ID: <WED.5.FEB.2003.001551.0200.CRISPIN@NEWDAWN.SZ>

Dear Margaret

I will try to get a picture of a small failed portion of a 3mm 3CR12 grate
that has been used for several years. It is installed at a company called
"Gone Rural" and they use it to fire large grass dyeing tanks. It has
burned away at the top where the hottest secondary air mixes with the
hottest part of the flame (est 800-900 C).

Like Paul, I have no failures of the smaller stoves (yet) as they are not
old enough.

It might be useful to use a piece of galvanized sheet metal in the tests as
well, perhaps 0.6mm which is common but any thickness will do. As it has a
sacrificial coating, the erosion of the surface should be non-linear with
time.

I favour thinner sheets than 3mm for the tests because it is more realistic
for use in a real stove.

We are using 1.2mm 3CR12 grates which when rolled, punched and formed, are
strong even when very hot. Also, using mild steel that thin at those temps
will probably give a reasonably short time for there to be significant
material loss, probably to the point of perforation, within the test period.

One of the most common materials used in ultra-low cost stoves is oil drums.
It might be interesting to toss a piece of that into the test as well, in
spite of the thickness not being the same.

If you standardize the test it can be repeated for other materials for
comparison which would be great.

Regards to all the students embarking on this useful experiment!
Crispin

From tmiles at TRMILES.COM Tue Feb 4 18:55:05 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:11 2004
Subject: Combustion Chambers
Message-ID: <TUE.4.FEB.2003.155505.0800.TMILES@TRMILES.COM>

The following is a concatenation (or is it contamination?) of a discussion in ETHOS regarding ceramic combustion chambers. It is a nice record of what has been accomplished with floor and roof tiles.

It would be useful to know if tiles from rural industry have been characterized for strength properties. That could provide a basis for comparison with current research on modified bricks and tiles by Damon Ogle and others which are being tested at U Dayton. Various members have asked for increased strength and resistance to spalling or abrasion in tiles. I suspect that the composition of the clay and preparation of the mix (e.g. inclusion of alkali from straw for example) before firing or sintering has much to do with these properties. There is probably much that is known to artisans in the field.

The use of common materials is all the more reason for house building and stove building to go hand in hand. There is an interesting table on the effect of clay preparation on brick properties in information by GTZ at USAID ENCAP http://www.encapafrica.org/sectors/brick.htm Internet and Print Resources: Brick and Tile Production by Micro and Small-Scale Enterprises

Ken Goyer:
I believe that some of the degradation in the elbow that
looks like abrasion is actually due to spalling of the ceramic surface.

Don O'Neal:
If we can hold thermal properties where they are today and increase strength and abrasion resistance we would have a winner. If we
improve thermal properties without the strength we still are not there.

See production of baldosas for HELPS stoves at http://www.trmiles.com/stoves/Oneil/Baldosas.html

Dean Still:
When I try to help folks in other countries design better stoves the Rocket elbow is really the only difficult part to create because it has to be refractory, in other words, able to withstand heat.

Barry Wheeler, who worked in Rwanda for two years after the massacre, is living in Thailand teaching AT in a university there. He responds to the
query about baldosa (ceramic floor tile): "Hey Dean! Very cool! Looks great, and I'm sure makes a great combustion
chamber. Good work, and grands felicitations! Yes, floor tiles and roof tiles (clay) are/can be made in Rwanda, as
are fired clay bricks, similar to the ones in your photo. As you did in Central America, you could just work with local masons to create the mold
and fire the clay in exactly the shape you want for the combustion chamber construction."

This is potentially good news! Finding refractory floor tiles, testing that they hold up in a Rocket elbow, is what Damon and Mike just did yesterday in
Honduras. Using locally made floor tile and surrounding it with locally available insulation creates the inner working parts for many types of fuel
efficient stoves, like a modified Lorena or a griddle stove, or a single burner stove with or without chimney, etc...When Larry discovered the
refractory floor tile perhaps he found a solution that is widely available?

Larry Winiarski:
I started the use of the rustic, hand made "Baldosas" for combustion chambers in rocket type stoves and ovens in Nicaragua about 3 years ago. These are different then what you might think of when you say floor tile. They are NOT a hard dense compacted clay tile such as we might buy for a floor tile. Rather. they are like an old fashioned hand made brick where the clay is pushed rather damp into a one inch thick mold. . this baldosa is relatively porous. if you put one that has been fired in water it produces a lot of bubbles. It is relatively soft and cuts easily with a sharp saw but it also contains a lot of sand like grains which rapidly dull a conventional saw blade or hacksaw blades. I think this grainy component serves the purpose of of the "grog" that potters use to make a clay more refractory. It looked to me like they were making the old style clay roofing tiles at the same time as the baldosas, possibly out of the same clay mix. INDEED we have made combustion chambers from old style, soft,roofing tiles that we cut into strips to form the rocket combustion chambers with built in expansion joints. Having the tile in strips allows us to form a better cross section from the tapered roof tiles. I suspect these are available in many parts of the developing world.

Tom Miles:
Clay roofing tiles, teja de barro, what a creative use of a common material. A survey of 1.2 million homes in Honduras indicates that clay tile roofs account for about 55% of rural homes and about 20% of urban dwellings. Clay and ceramic flooring however accounted for only about 3% of the rural homes.

Jim Wilmes:
My experience in El Salvador confirms Tom's statistics about Honduras. When I went to replace a ceramic elbow that had self-destructed, I couldn't find
clay floor tiles anywhere as an off-the-shelf product, only as something that could be specially made. But the curved roof tiles where plentiful.
It turned out that three tiles joined together made almost a perfect circle. So we just cut the tiles to the desired length to make a cylinder, and
used a little mud and wire to hold them together. They're significantly thinner than the floor tiles we worked with in Guatemala, so they shouldn't
absorb quite as much heat during startup. I can't tell you how well they've survived, though.

I think that thermal cycling, combined with an abrasion resistance test, is critical. These tests would most closely resemble the assaults that the materials typically encounter in a real stove. It's important that the abrasion test be performed on material that has been heated to internal stove temperatures, if possible. Ceramic fiber cylinders, for example, looked very attractive until we noticed that they lost much of their abrasion resistance at high temperatures.

Stuart Conway:
A test of thermal cycling would be very useful for determining how long some of our ceramic and insulating stove materials will last in Central America. Our oldest Justa stoves are approaching four years old now and are still holding up.

Dale Andreatta:
As I see it, with regard to these insulative bricks, we need to answer the
following questions, with the first question being the overriding one:

1. How much does one have to decrease thermal conductivity into the stove
body before you reach the point of diminishing returns, and are we at that
point with our new insulative bricks? Are we at the point where we should
stop worrying about reducing the thermal conductivity, and start
concentrating on keeping high strength in our bricks?

2. What are the thermal properties (density, specific heat, thermal
conductivity, thermal diffusivity-measure any 3 and you can calculate the
fourth) of our current insulative bricks, and of regular bricks?

3. How does thermal conductivity vary with density (I predict thermal
conductivity will be roughly proportional to density squared).

I believe that answering these questions should not be difficult. I know
the people at University of Dayton are working on these things, but, as Mark
Bryden said at the Seattle meeting, university people are good, but slow.

I propose to measure the thermal properties of the bricks, and answer the
above questions, provided that no one has done this previously, and provided
that people are willing to send me samples of insulative bricks (Dean?). I
believe these questions can be answered in about a month, accurately enough
to be useful in guiding our work, though probably not as accurately as the
Dayton people can answer them.


 

From adkarve at PN2.VSNL.NET.IN Wed Feb 5 09:24:34 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:11 2004
Subject: Collaboration with Tata Energy Research Institute
Message-ID: <WED.5.FEB.2003.195434.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Ms Mathur,
our char briquettes are marketed exclusively in Pune city. As a means of
selling the briquettes, we developed a highly efficiently stove-and cooker
system, which uses just 100 g of the briquettes to cook rice, beans and a
vegetable (or meat) for a family of 4 or 5 persons. In rural Maharashtra,
people eat a flat unleavened bread made
either from sorghum, pearl millet or finger millet. They cannot use our
stove-and-cooker system for making this bread. In Maharashtra, it is the
well-to-do people in the
cities who eat rice. Therefore, our cooker has no market in the rural
areas.
Also, the rural households get enough fuel in the form of cotton or
pigeonpea stalks,
maize cobs, sugarcane rhizomes etc. They also have Prosopis
juliflora, which grows in profusion in rural Maharashtra. With so much free
fuel available to them, the villagers are just not interested in buying our
char briquettes. It was initially our idea to introduce the briquettes to
the people living in the slums in the cities, but we discovered that the
urban poor too do not eat rice and they too prefered to use
wood instead of charcoal. The wood they use comes mainly from discarded
packing cases, available to them free of cost. The buyers of our stove and
cooker system belong to the urban middle class. We currently sell almost 20
cookers daily and with increasing sale of the cookers, the sale of charcoal
is also increasing by leaps and bounds. We have about a dozen kilns
operating in the countryside, but our
briquetting capacity cannot keep pace with the demand, because of severe
electricity shortage.
We are now experimenting with the mass manufacture of honeycombe briquettes.
They are made with the help of a mould and without the use of electricity. I
think that
we have found the ideal design for this type of briquettes, and are now in
the
process of producing moulds to produce them.
We were successful in commercialising our improved cookstoves in rural
Maharashtra,
and were disseminating them through the National Programme on Improved
Cookstoves. The most popular of our models were without a chimney. However,
because Ministry of Non-Conventional Energy Sources withdrew the recognition
of
chimneyless models, the programme received a setback. Now that the subsidy
has been withrawn and the users are free to choose the models, we want to
revive our models without chimney. Although they produce visibly less smoke
and soot than the traditional cookstoves, we were told by researchers who
tested their emissions, that our chimneyless models were highly polluting.
One of the most popular of our chimneyless models is a clay replica of the
chimneyless metallic stove, which received a clean chit from the Ministry of
Non-Conventional Energy Sources. So the emissions from our chimneyless
models need to be verified again.
The third area in which we are working is biogas. If one compaired the
money and effort spent by the Government on biogas, and its actual spread in
India, one must admit that this technology has failed. We are developing
new models and processes, and we feel that our new
technology would be more readily accepted by the users. But at the present
moment, we have only laboratory results and nothing concrete to show in the
field. In any case, our biogas
technology is also not going help the lower end user. Thus, as you can see,
neither the char briquettes nor the biogas would be used by the lower end
user. The poorer households would continue to use fuels that they can get
cheaply or
preferably free of cost. In such a scenario, all we can do is to give them a
low cost cooking device which is more efficient and less polluting than
their present device.
Yours A.D.Karve
-----Original Message-----
From: Nayanika Mathur <nayanika@teri.res.in>
To: adkarve@pn2.vsnl.net.in <adkarve@pn2.vsnl.net.in>
Date: Wednesday, February 05, 2003 11:50 AM
Subject: Collaboration with Tate Energy Research Institute

Dear Sir/Madam,

Since ARTI has done significant work in the creation of an integrated fuel
from waste systemthat can create thousands of rural entrepreneurs all over
the world, while saving trees and reducing petro dependence,we would request
you to suggest some case example to us from your working area which we can
study. Our attempt shall be to see how the livelihood based approach to cons
ervation of woody biomass can be used for conservation at the wider level.
We will document these examples as the case studies and publishing them. We
could also work towards writing joint publications. In any case, due
acknowledgement will be given to all the organisations assisting us in
information collection.

We would really appreciate an early response from your side. In case of any
clarifications, please feel free to contact me or in my absence my
colleague, Ms Ritu Upreti, Research Associate, Rural Energy Group, TERI, New
Delhi.

Looking forward to working together.

Regards,

Nayanika Mathur
Research Associate
TERI

From dstill at EPUD.NET Wed Feb 5 09:17:07 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:11 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <WED.5.FEB.2003.061707.0800.DSTILL@EPUD.NET>

Dear Stovers,

The clay/sand stoves shown by Christa Roth and Christoph Messinger are,
unfortunately, good examples of stoves that have in laboratory tests been
shown to use more firewood than three stone fires. Just surrounding the fire
with heavy earthen materials does not raise combustion temperatures. The
mass actually lowers combustion temperatures for hours until the stove body
has come up to temperature itself. The heat is diverted from its intended
purpose: to cook food. Why heat up hundreds of pounds of stove body when
cooking five - ten pounds of food?

A three stone fire can be quicker, smokes less, uses less fuel.

Clay/sand is not insulation. This was the mistake made by the inventors of
these types of stoves, including Aprovecho. Earthen material was thought to
insulate around the fire but we later realized that good insulation is
pockets of air in a lightweight, low conducting material. Naturally
available sources include pumice rock, perlite, vermiculite, wood ash, etc.

To improve on the properly operated three stone fire requires an insulated
combustion chamber which can be made from locally available materials as
well. Forcing the heat to scrape against the sides of the pot is the true
advantage of the good cook stove, improved heat transfer can help to save
large percentages of wood. To do this without first cleaning up combustion
in an insulated combustion chamber can create more harmful emissions,
however. Both hotter, cleaner combustion and improved heat transfer can
easily be designed into a modern, improved ceramic cook stove.

I very much do not like being critical of the enthusiastic work of others.
But these types of stoves have been built over and over in the last twenty
years without regard to the careful work of Baldwin, Prasad, Emma George
just recently in Uganda, etc. who showed that mass is detrimental to
efficient cook stoves. Let's just change the recipe and make the combustion
chambers of these stoves insulative. The stoves will be just as vernacular
but they will do in actuality what was hoped for by designers.

All Best,

Meaning no offense,

Dean Still

From stoves at ECOHARMONY.COM Wed Feb 5 14:26:00 2003
From: stoves at ECOHARMONY.COM (Grant Ballard-Tremeer)
Date: Tue Aug 10 18:30:12 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <WED.5.FEB.2003.192600.GMT.STOVES@ECOHARMONY.COM>

Hello Dean,

I agree completely with your criticisms of the heavy mass stoves shown
in the pictures at www.ecoharmony.net/hedon/malawistoves.php - fuel
inefficient and smokey.

The clay stove (www.ecoharmony.net/hedon/claystove.php) is, I believe,
fuel saving although probably not 'lower smoke emitting' - it is a
modification of the ITDG design used in Kenya, which has been
carefully tested/monitored over the years. After significant emissions
& efficiency testing I did some years ago (www.ecoharmony.com/thesis)
I too was skeptical about fuel savings from the clay stoves being
disseminated, but have since been shown convincing evidence from ITDG
& GTZ. On the emissions front, though, ITDG's recent Indoor Air
Quality testing of these devices in use have not shown significant
emission reductions - or so I have heard.

Your point is still valid - it would certainly be much better to work
on and promote insulated, low-mass combustion chambers as you are
doing at Aprovecho! Would you be able to draft a similar 'how-to
guide' (similar style) on how to make the Rocket Stove. I know you
have some information at www.efn.org/~apro/attitlepage.html, but I
don't see any step-by-step guidelines which development organisations
could follow. Would you be willing to help make one?

I will introduce some additional explanation on the existing online
how-to guides (Christa - could you help?) so as not to confuse/mislead
readers.

Thanks for the contribution

Grant

Wednesday, February 5, 2003, 2:17:07 PM, you wrote:

DS> Dear Stovers,

DS> The clay/sand stoves shown by Christa Roth and Christoph Messinger are,
DS> unfortunately, good examples of stoves that have in laboratory tests been
DS> shown to use more firewood than three stone fires. Just surrounding the fire
DS> with heavy earthen materials does not raise combustion temperatures. The
DS> mass actually lowers combustion temperatures for hours until the stove body
DS> has come up to temperature itself. The heat is diverted from its intended
DS> purpose: to cook food. Why heat up hundreds of pounds of stove body when
DS> cooking five - ten pounds of food?

From stephen.gitonga at UNDP.ORG Wed Feb 5 15:36:02 2003
From: stephen.gitonga at UNDP.ORG (Stephen Gitonga)
Date: Tue Aug 10 18:30:12 2004
Subject: [hedon] Re: Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <WED.5.FEB.2003.153602.0500.STEPHEN.GITONGA@UNDP.ORG>

Dear stovers

A few days ago, there was a message that came through the stovers list
which touched on the foods that some communities in developing countries
use. That was quite important because you cannot design a stove without
knowing what use it will be put to and by who. Based on my own personal
experience in the area of improved stoves for development, the picture
is only complete when some of the following
are included in the stove design (from the users point of view)
1) Type of foods routinely used by the communities. Some foods cooked by
communities takes six hours to cook and clay and sand stoves proves
quite useful in that respect. The mass will take the heat for the first
30 minutes but later the mass retains the heat within itself as the fire
is directed to the pot.

This makes it very ideal where the heat is used for house warming as the
food cooks. Certainly, the stove made that way with a community that
uses it in that way is far much useful and effective than a three stone
fire. Let me elaborate on the six hour cooking period. There is the
heating and boiling period for about 1 and half hours to two hours, then
there is the heating period and the the
simmering period. In all these stages of cooking, different feeding of
firewood to the fire is required. Take an example when cooking matoke
(steamed bananas in Uganda) for example, you need a steaming period that
needs very low level of heating and the mass of sand and clay plays a
great part in achieving the right cooking environment. Dry maize and
beans (Githeri) in Kenya takes between 5 and 6
hours to just bring it to the cooking stage. Then it has to be pounded
which is another 30 minutes to one hour exercise etc. Using that
example, the samples of stoves posted are far more efficient than use
of a three stone fire.

2) Length of time the food takes to cook. This is more important as the
stove efficiency consideration in design.
3) The type of pot used in the cooking. Many pots used cannot fit very
well with a situation where heat is to be forced to scrape against the
sides of the pot. A very unfortunate reality. So other ways of achieving
some level of efficiency are devised including the stoves posted by
Christa and Christoph. which are better in the field than the three
stone fire.

3) Some foods requires pounding as it cooks which influences the way the
pot has to sit on the stove.
4) The most forgotten aspects by stove designers is that the fire is
used by the users for other activities apart from cooking e.g. house
warming and also warming themselves around the fireplace as they
socialise, roasting of maize or potatoes, and even in some cases to
provide light in the kitchen (some kitchens have no lamps) etc. as
culture demands. Some form of allowance to this is needed if the
community will adopt the stove fully otherwise they will still make
another side-fire against the most efficient stove in the kitchen to
carry out the other functions of the fire place.

After all that has been tackled, the secondary considerations from the
users point of view include
1) stove design and its looks: Is the stove appealing to the eye?
2) affordability or accessibility. Is the stove affordable or can it be
made easily by the user or a helper?
3) efficiency: is it helping to save some wood? Sometimes the
communities have looked for solutions spontaneously to save on wood and
we have many examples in East Africa. Please also look at some of those
spontaneous designs at the small booklet that I wrote by the name
"Appropriate mud stoves in East Africa" sold by ITDG
Publishing(www.itdg.org) which shows some of those mud stoves practiced
by
communities to try to address the woodfuel problem.
5) durability: They are more interested with something that will last
for sometime.
6) portability: The issue of whether the stove could be moved from one
place to the other is important with some communities.

You will realise that it is only in stove efficiency where the user and
the developer may find a common ground. But the reality is that common
ground must be cultivated in all the other aspects if stoves programme
will be successive.

Now looking at the stoves that were posted by Christa Roth and Christoph
Messinger, I bet they are based on the consideration of the issues I
have raised above based on the specific community they are dealing with
. In that respect they might not be very appealing to somebody focused
on efficiency alone, but they are the most appropriate for the specific
community they are dealing with. The stoves
are based on field experiences and I would assume they have incorporated
many aspects of the users perspective to try to reconcile the users
culturally influenced considerations with the stove designers
consideration. They, therefore, possibly represent the true picture of
what is practical on the ground to that specific community rather than
in the laboratory or in research environment. They
represent the meeting point between theory and practice.

These are my personal views and I hope they will help in the good work
of finding the true solution to better household cooking in the
developing world.

Regards

Stephen Gitonga

 

 

Dean Still wrote:

> Dear Stovers,
>
> The clay/sand stoves shown by Christa Roth and Christoph Messinger are,
> unfortunately, good examples of stoves that have in laboratory tests been
> shown to use more firewood than three stone fires. Just surrounding the fire
> with heavy earthen materials does not raise combustion temperatures. The
> mass actually lowers combustion temperatures for hours until the stove body
> has come up to temperature itself. The heat is diverted from its intended
> purpose: to cook food. Why heat up hundreds of pounds of stove body when
> cooking five - ten pounds of food?
>
> A three stone fire can be quicker, smokes less, uses less fuel.
>
> Clay/sand is not insulation. This was the mistake made by the inventors of
> these types of stoves, including Aprovecho. Earthen material was thought to
> insulate around the fire but we later realized that good insulation is
> pockets of air in a lightweight, low conducting material. Naturally
> available sources include pumice rock, perlite, vermiculite, wood ash, etc.
>
> To improve on the properly operated three stone fire requires an insulated
> combustion chamber which can be made from locally available materials as
> well. Forcing the heat to scrape against the sides of the pot is the true
> advantage of the good cook stove, improved heat transfer can help to save
> large percentages of wood. To do this without first cleaning up combustion
> in an insulated combustion chamber can create more harmful emissions,
> however. Both hotter, cleaner combustion and improved heat transfer can
> easily be designed into a modern, improved ceramic cook stove.
>
> I very much do not like being critical of the enthusiastic work of others.
> But these types of stoves have been built over and over in the last twenty
> years without regard to the careful work of Baldwin, Prasad, Emma George
> just recently in Uganda, etc. who showed that mass is detrimental to
> efficient cook stoves. Let's just change the recipe and make the combustion
> chambers of these stoves insulative. The stoves will be just as vernacular
> but they will do in actuality what was hoped for by designers.
>
> All Best,
>
> Meaning no offense,
>
> Dean Still
>
> ----------
> Does your organisation feature on the Shell Foundation online database? Take a look at http://ecoharmony.net/hedon/org.php to find out more.
>
> Please feel free to forward this mail to any of your colleagues or business partners. We rely on users to spread the word about HEDON to the entire Household Energy community. In addition, please consider adding your own material to the HEDON web page resources. This is a simple process and can go a long way towards generating publicity for your activites among a select audience of professionals.
>
> For more information about HEDON visit:
> http://ecoharmony.net/hedon
>
> NOTE: Advertisements in this message have been added by Yahoo Groups who provides us with free email group services. HEDON does not endorse products or support the advertisements in any way.
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

From psanders at ILSTU.EDU Wed Feb 5 15:54:24 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:12 2004
Subject: metals testing
In-Reply-To: <014601c2cc9b$44872560$2a5afea9@home>
Message-ID: <WED.5.FEB.2003.145424.0600.PSANDERS@ILSTU.EDU>

Margie and all Stovers,

I agree with Crispin that thinner materials should be included in the
testing. Your class time is limited, and you do want to destroy some of
the metal!!!

Although it might sound UN-scientific, use whatever you can find. Or
"whatever can you can find". Remember that "tincanium" is a reality in
some places. People who live day-by-day could easily be using a stove
that might last season-by-season. They use it until it is burned out, and
then get another short-life identical product because that is what they or
neighbors can find, make or purchase at very low costs.

As a university professor, I can suggest that even experiments on products
(sheet metal in this case) that we know will be quickly destroyed will be
useful as learning experiences AND can provide some low-end benchmarks
(points of reference) for comparison with the better and thicker sheet
metals. When you make a graph of the data, you will have some "low-end"
data instead of unknown extrapolations. And you might have some real
surprises in the process. We all await your results.

Editorial: In American education we are so focused on the "quality" and
the "high end" materials that we neglect (or intentionally overlook) what
is the "reality" for impoverished people. We tend to think we must "find
something new or better" IN THE CONTEXT OF AMERICAN AFFLUENCE. For the
billions of people who would benefit from the kinds of stoves that we
discuss, "new and better" could be the selection of metal from a scrap heap.

Also, I want to give the HIGHEST PRAISE to you and your students and your
university for considering and actually doing "in-class" studies that are
intended to benefit the needy, the truly needy in this world.

I (and probably ALL of the Stovers) appreciate your efforts.

Paul S. Anderson
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

***********************
At 12:15 AM 2/5/03 +0200, Crispin wrote:
>Dear Margaret
>
>I will try to get a picture of a small failed portion of a 3mm 3CR12 grate
>that has been used for several years. It is installed at a company called
>"Gone Rural" and they use it to fire large grass dyeing tanks. It has
>burned away at the top where the hottest secondary air mixes with the
>hottest part of the flame (est 800-900 C).
>
>Like Paul, I have no failures of the smaller stoves (yet) as they are not
>old enough.
>
>It might be useful to use a piece of galvanized sheet metal in the tests as
>well, perhaps 0.6mm which is common but any thickness will do. As it has a
>sacrificial coating, the erosion of the surface should be non-linear with
>time.
>
>I favour thinner sheets than 3mm for the tests because it is more realistic
>for use in a real stove.
>
>We are using 1.2mm 3CR12 grates which when rolled, punched and formed, are
>strong even when very hot. Also, using mild steel that thin at those temps
>will probably give a reasonably short time for there to be significant
>material loss, probably to the point of perforation, within the test period.
>
>One of the most common materials used in ultra-low cost stoves is oil drums.
>It might be interesting to toss a piece of that into the test as well, in
>spite of the thickness not being the same.
>
>If you standardize the test it can be repeated for other materials for
>comparison which would be great.
>
>Regards to all the students embarking on this useful experiment!
>Crispin

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From tmiles at TRMILES.COM Wed Feb 5 16:38:16 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:12 2004
Subject: [hedon] Re[2]: Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <WED.5.FEB.2003.133816.0800.TMILES@TRMILES.COM>

Dean,

I think the effort and experience that IFSP has had can lead to improved designs with increased benefits.

Regardless of the apparent shortcomings of the stove design, from the testimony of the users that Christa reports, it serves significant needs and provides improvements compared with the three stone fire. This is reflected in the name they have chosen for the stove:"'Chitetezo mbaula', which in the vernacular language means 'the protecting stove'. The name was chosen by the women in Mulanje, as one of the biggest advantages they perceived is the improved safety of the stove as compared to the traditional three-stone-stove: they feel better protected themselves as their clothes are not so likely to catch fire and the risk for children getting burnt is reduced."

Fuel savings of up to 80% of the firewood, they say, results from the ability to burn alternative fuels like "pigeon pea stalks, maize husks and other residues, which don't burn well in the three-stone-stove but do well in the improved stove because of the higher heat developed inside. Participatory tests in public cooking demonstrations have given an average of ca. 60% saving of firewood for the improved stove as compared to the three-stones."

So having made significant gains in safety and substitution of wood fuel the challenge would be develop more efficient designs. Maybe you can't do that and preserve portability all in one stove. So you wind up with a mix of stoves to suit the local needs.

Regards,

Tom Miles


----- Original Message -----
From: Grant Ballard-Tremeer
To: Dean Still ; STOVES@LISTSERV.REPP.ORG ; hedon@yahoogroups.com
Cc: Christa Roth
Sent: Wednesday, February 05, 2003 11:18 AM
Subject: [hedon] Re[2]: Different Types of Energy Saving Stoves In Southern Malawi

Hello Dean,

I agree completely with your criticisms of the heavy mass stoves shown
in the pictures at www.ecoharmony.net/hedon/malawistoves.php - fuel
inefficient and smokey.

The clay stove (www.ecoharmony.net/hedon/claystove.php) is, I believe,
fuel saving although probably not 'lower smoke emitting' - it is a
modification of the ITDG design used in Kenya, which has been
carefully tested/monitored over the years. After significant emissions
& efficiency testing I did some years ago (www.ecoharmony.com/thesis)
I too was skeptical about fuel savings from the clay stoves being
disseminated, but have since been shown convincing evidence from ITDG
& GTZ. On the emissions front, though, ITDG's recent Indoor Air
Quality testing of these devices in use have not shown significant
emission reductions - or so I have heard.

Your point is still valid - it would certainly be much better to work
on and promote insulated, low-mass combustion chambers as you are
doing at Aprovecho! Would you be able to draft a similar 'how-to
guide' (similar style) on how to make the Rocket Stove. I know you
have some information at www.efn.org/~apro/attitlepage.html, but I
don't see any step-by-step guidelines which development organisations
could follow. Would you be willing to help make one?

I will introduce some additional explanation on the existing online
how-to guides (Christa - could you help?) so as not to confuse/mislead
readers.

Thanks for the contribution

Grant

Wednesday, February 5, 2003, 2:17:07 PM, you wrote:

DS> Dear Stovers,

DS> The clay/sand stoves shown by Christa Roth and Christoph Messinger are,
DS> unfortunately, good examples of stoves that have in laboratory tests been
DS> shown to use more firewood than three stone fires. Just surrounding the fire
DS> with heavy earthen materials does not raise combustion temperatures. The
DS> mass actually lowers combustion temperatures for hours until the stove body
DS> has come up to temperature itself. The heat is diverted from its intended
DS> purpose: to cook food. Why heat up hundreds of pounds of stove body when
DS> cooking five - ten pounds of food?

----------
Does your organisation feature on the Shell Foundation online database? Take a look at http://ecoharmony.net/hedon/org.php to find out more.

Please feel free to forward this mail to any of your colleagues or business partners. We rely on users to spread the word about HEDON to the entire Household Energy community. In addition, please consider adding your own material to the HEDON web page resources. This is a simple process and can go a long way towards generating publicity for your activites among a select audience of professionals.

For more information about HEDON visit:
http://ecoharmony.net/hedon

NOTE: Advertisements in this message have been added by Yahoo Groups who provides us with free email group services. HEDON does not endorse products or support the advertisements in any way.

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

From koopmans at LOXINFO.CO.TH Wed Feb 5 17:27:55 2003
From: koopmans at LOXINFO.CO.TH (Auke Koopmans)
Date: Tue Aug 10 18:30:12 2004
Subject: Combustion Chambers
Message-ID: <THU.6.FEB.2003.052755.0700.KOOPMANS@LOXINFO.CO.TH>

With regard to properties of clay to be used for ceramic stoves.stove parts
quite a bit of work has been done in the UK as well as by myself here in
Thailand.

To sum up the results in short is that the ratio of clay or C (all particles
below 2 micron) and what we called the non-clay or NC component (anything
above 2 micron in a clay) should be below 1 (C/NC < 1) to be reasonable sure
that the stove will not crack during use. The C to NC ratio however is a
very incomplete description of clay. Other factors do influence also the
performace of ceramic stoves during use. Production methods, method and
speed of drying, etc. all play a role.

For those interested in the subject, ITDG has published a small booklet:
Clay Testing; A manual on the clay/non-clay ratio measurement technique by
Anura Gaspe (who got his PhD based on this work), Prof. Peter Messer and
Pete Young (ISBN 1 85339266 9). In case it is no longer available I do have
a copy and I would be willing to scan it (about 18 pages) and have it put on
the Stove website or at our own website http://www.rwedp.org (would have to
check if copyright apllies - maybe Liz Bates can shed some light on that).

Hope that this helps

Auke Koopmans

From tmiles at TRMILES.COM Wed Feb 5 21:38:06 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:12 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <WED.5.FEB.2003.183806.0800.TMILES@TRMILES.COM>

Grant,

Go to www.trmiles.com/stoves and look at the list of Aprovecho guides in pdf format
in "NEW"
a Simple Plans for the Sunken Pot Aprovecho Stove (pdf 750 kb)
b.. Simple Plans for the Aprovecho Double Burner Rocket Stove (pdf 400 kb)
c.. Simple Plans to Build the Justa Stove (pdf 1200 kb)
d.. Rocket Stove User Guide (pdf 40 k)
e.. Rocket Stove Design Guide (pdf 100kb)

The Justa is the basic stove. I believe that the Sunken Pot and Double Burner were
developed by Lanny Henson and Peter Scott for or during Peter's work last year with
GTZ in Southern Africa.

For additional references and links do a search on the Biomass Cooking Stoves site
for "rocket"

Regards,

Tom Miles

----- Original Message -----
From: "Grant Ballard-Tremeer" <stoves@ecoharmony.com>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, February 05, 2003 11:26 AM
Subject: Re: [STOVES] Different Types of Energy Saving Stoves In Southern Malawi

Would you be able to draft a similar 'how-to
guide' (similar style) on how to make the Rocket Stove. I know you
have some information at www.efn.org/~apro/attitlepage.html, but I
don't see any step-by-step guidelines which development organisations
could follow. Would you be willing to help make one?

From pverhaart at OPTUSNET.COM.AU Thu Feb 6 00:19:17 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:12 2004
Subject: [hedon] Re: Different Types of Energy Saving Stoves In
Southern Malawi
In-Reply-To: <3E4175B2.399632A7@undp.org>
Message-ID: <THU.6.FEB.2003.151917.1000.PVERHAART@OPTUSNET.COM.AU>

At 15:36 05/02/03 -0500, you wrote:
>Dear stovers
>
>Snip
>
>This makes it very ideal where the heat is used for house warming as the
>food cooks. Certainly, the stove made that way with a community that
>uses it in that way is far much useful and effective than a three stone
>fire.

A clean burning three sone fire which is also used for space heating has an
efficiency of 100 %. No chimney stove can touch that.

>Let me elaborate on the six hour cooking period. There is the
>heating and boiling period for about 1 and half hours to two hours, then
>there is the heating period and the the
>simmering period. In all these stages of cooking, different feeding of
>firewood to the fire is required. Take an example when cooking matoke
>(steamed bananas in Uganda) for example, you need a steaming period that
>needs very low level of heating and the mass of sand and clay plays a
>great part in achieving the right cooking environment. Dry maize and
>beans (Githeri) in Kenya takes between 5 and 6
>hours to just bring it to the cooking stage.

Dry maize and beans are soaked overnight in so-called energy squandering
Western world. After this they need no more than half an hour of simmering.
More than 20 years ago Waclaw Micuta of the Bellerive Foundation
demonstrated this in, I believe Kenya.

>Then it has to be pounded
>which is another 30 minutes to one hour exercise etc. Using that
>example, the samples of stoves posted are far more efficient than use
>of a three stone fire.

I don't believe it, the heavyweight clay stoves are notoriously difficult
to adjust in heat output. It usually comes down to starving the fire of
oxygen and nobody cares because the thick smoke is conducted to the outside
by a chimney. Only the neighbours could possibly object.

>Now looking at the stoves that were posted by Christa Roth and Christoph
>Messinger, I bet they are based on the consideration of the issues I
>have raised above based on the specific community they are dealing with

A few days ago A.D. Karve said that as really efficient and versatile
stoves, such as gas burning stoves appear, those doind the cooking are more
than willing to adapt their utensils to the new stove instead of the other way.

Cheers

Peter Verhaart

From kchisholm at CA.INTER.NET Thu Feb 6 01:06:53 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:12 2004
Subject: [hedon] Re: Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <THU.6.FEB.2003.020653.0400.KCHISHOLM@CA.INTER.NET>

Dear Peter
----- Original Message -----
From: "Peter Verhaart" <pverhaart@OPTUSNET.COM.AU>
...del...
> >
> >This makes it very ideal where the heat is used for house warming as the
> >food cooks. Certainly, the stove made that way with a community that
> >uses it in that way is far much useful and effective than a three stone
> >fire.
>
> A clean burning three sone fire which is also used for space heating has
an
> efficiency of 100 %. No chimney stove can touch that.
>
The net efficiency of a fireplace within a home is about 5%, because of the
gross amount of excess air drawn up the stack/chimney. A clean burning three
stone fire would have a "virtual chimney", in that the products of
combustion must escape. As bad as the normal fireplace efficiency is, I
would think that a three stone fire would be even worse.

There is a big gap between 100% and <5%. Perhaps we are talking about
different things?

Kindest regards,

Kevin

From rstanley at LEGACYFOUND.ORG Thu Feb 6 01:47:03 2003
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:12 2004
Subject: (or fuels ?): Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <THU.6.FEB.2003.094703.0300.>

Or,

While many are now looking at stove designs for the varieties of cooking
conditions, why not also look at the fuel design and composition to meet these
conditions. This is where we can all learn a lot from traditional knowledge. As
regards the briquette, the experience is not different: Everywhere we extend
the technology, the local user / producer eventually adapts the recipe and
composition, on their own, to their own tastes with their own resources.

As to ingredients there is an interesting question emerging which I'd like to
pose to the group at large, ant it concerns the combustion of plastic bags:

One group in West Africa and another in Nepal is interested in seeing whether
we can include shredded small plastic shopping bags in the briquette. I have
seen this done routinely by local production groups Malawi ( These were
routinely being sold to the same customers and there seemed to be no complaint.
It is probably based on the fact that they often use the bags as a starter fuel
ignited and dripped onto the firewood or charcoal (like the wax off a burning
candle). That is anecdotal evidence but it is hardly a basis for
recommendations to others. There was little concern for fine tuning the
information then as few expressed any interest in replicating the Malawi blend.

Now, a year and a half on, the issue seems to be literally "heating up" as
the plastic bag is rapidly becoming the national flower in so many places.

I had posed this question , casually, some time ago and two members replied
with opinions ranging from " it would have little to no negative effect, if it
was burned at high temps (above 400 degrees c) to "I would not touch it with a
three meter pole". Since the briquette will typically reach 800 deg. C (within
usually 10 minutes) I took this as a positive but in that it countered so
dramatically that it gave rise to caution.

We therefore need to garner a group wide opinion to come to some sort of
conclusive position.

One of the holey briquettes will weigh in dry (ambient moisture) at
125 to 150 grams and have a volume of 550 to 575 cc's. One such small
plastic bag (say large enough to hold a three liters of liquid) will
weigh about 8 to 10 gms.

As ever your advice and insights would be most welcome.

Thanks,

Richard Stanley

Kampala, Uganda

From kchisholm at CA.INTER.NET Thu Feb 6 02:18:48 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:12 2004
Subject: (or fuels ?): Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <THU.6.FEB.2003.031848.0400.KCHISHOLM@CA.INTER.NET>

Dear Richard

It depends on the plastic employed to manufacture the bag...

If it was polyethylene, with inert fillers, and non-toxic inks, then there
should be no environmental problem. However, if it was a poly vinyl chloride
(PVC) based plastic, there is potential for significant problems. On
combustion, the chlorine is released, and there is a potential to create
dioxanes and possibly other nasty compounds.

From pverhaart at OPTUSNET.COM.AU Thu Feb 6 05:31:00 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:12 2004
Subject: (or fuels ?): Different Types of Energy Saving Stoves In
Southern Malawi
In-Reply-To: <3E4204D1.200C2333@legacyfound.org>
Message-ID: <THU.6.FEB.2003.203100.1000.PVERHAART@OPTUSNET.COM.AU>

Plastic bags, usually made of polyethene could possibly act as a binder for
briquettes. A temperarure above 200 C (my guess) will be needed.
Polythene, being a compound containing only carbon and hydrogen must have a
high combustion value and produces no health threatening combustion
products if burned completely.

Peter Verhaart

At 09:47 06/02/03 +0300, you wrote:
>Or,
>
>snip

>As to ingredients there is an interesting question emerging which I'd like to
>pose to the group at large, ant it concerns the combustion of plastic bags:
>As ever your advice and insights would be most welcome.
>
>Thanks,
>
>Richard Stanley
>
>Kampala, Uganda

From adkarve at PN2.VSNL.NET.IN Wed Feb 5 18:25:49 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:12 2004
Subject: Collaboration with Tata Energy Research Institute
Message-ID: <THU.6.FEB.2003.045549.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Tami, the fact that the metal model was declared to be non-polluting
while our clay model was, could be explained by the message from Dean Still
that just preceded yours on the stovers' group discussion. The metal stove
gets so hot during operation, that you can burn your hands if you
accidentally touched the body of the stove. Our clay stove gets just warm on
the outside. We used to cite this as an advantage, because a cooking
housewife is always surrounded by children of various ages from a few days
to year 5. It is obvious that the clay stove absorbs heat, and that the
lower temperature in the combustion chamber contributes to higher
concentration of pollutants in the fire. We shall try constructing the
stove with an insulative material instead of material that absorbs heat.
A.D.Karve
-----Original Message-----
From: Tami Bond <yark@u.washington.edu>
To: A.D. Karve <adkarve@PN2.VSNL.NET.IN>
Date: Thursday, February 06, 2003 12:00 AM
Subject: Re: [STOVES] Collaboration with Tata Energy Research Institute

>
>Dr. Karve,
>
>Thanks once again for an informative and educational message. I always
>appreciate your perspective on the integration of technology, marketing,
>and social considerations.
>
>> Although they produce visibly less smoke and soot than the traditional
>> cookstoves, we were told by researchers who tested their emissions, that
>> our chimneyless models were highly polluting.
>
>I am curious whether these results came from the measurements of indoor
>concentration that you referred to earlier. If so, what was measured? and
>what does 'highly polluting' mean-- CO concentrations or also PM? If only
>indoor concentrations were measured, I am also curious whether the
>diagnosis for chimneyed stoves as 'less polluting' is completely correct.
>Of course, the indoor concentration is of most interest for direct
>exposure to smoke from one's own cooking, and removing smoke from the
>breathing zone cannot be a bad idea. However, in the urban and peri-urban
>areas, local air quality is also an issue; and the addition of a chimney
>may or may not solve this problem. What do you think?
>
>Thanks so much!
>
>Tami Bond
>
>
>

From adkarve at PN2.VSNL.NET.IN Wed Feb 5 19:45:28 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:12 2004
Subject: [hedon] Re: Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <THU.6.FEB.2003.061528.0530.ADKARVE@PN2.VSNL.NET.IN>

The gist of the message by Stephen Gitonga is that the improved stoves
should best be designed in the geographic region where they would be used,
by persons who know the cooking habits of the target area and target
population and that they should be field tested by the potential users.
In India, we found that in the last fifty years, the cooking habits of the
urban population have undergone a drastic transformation. The rural
population gets most of its cooking fuel from agriculture and a little wood
from the surrounding area. But the local use of wood by the rural people
does not lead to drastic deforestation. However, the domestic fuel needs
of the large urban populations started to have a bad effect on the tree
population in the hinterlands. Therefore, about 50 years ago, the Government
of India reduced the price of kerosene so drastically, that the urban
housewives were weaned away from charcoal and wood. Later very cheap LPG was
introduced and today a majority of the urban houses use LPG. It would
interest stovers to know, that neither the kerosene stoves nor the LPG
stoves were designed to suit the cooking habits of the target population.
The designed were borrowed from abroad and the stoves were mass produced in
factories and sold to people without asking their opinion about them.
However the user friendliness of both these fuels and the cooking devices
was such, that housewives changed their cooking habits to suit the stoves.
This was really an eye-opener that showed that if the housewife got a really
good stove that satisfied most of her daily cooking requirements, she was
willing to use the stove. However such a stove had to be really good, i.e.
with a blue flame, absolutely without smoke or soot, quick to ignite/douse
and with a finger-tip control of the flame intensity.
The problem with the rural people is that they get their fuel absolutely
free of cost. My own colleagues in our institute use LPG in their city homes
and biomass burning mud stoves in their village homes, because in the
villages they get the fuel free of cost. Therefore, as far as the villages
are concerned, the so called improved stoves that we produce are a
compromise solution, in which the basic fuel is the same, i.e. stalks of
cotton or of pigeonpea, dung cakes, coppice shoots of surrounding trees,
rhizomes of sugarcane, maize cobs etc. All we can do is to make it burn
without polluting the indoor atmosphere. Even the efficiency of the stove is
not improtant to the users because the fuel is available to them free of
cost. Under such circumstances, they complain bitterly over every little
change. Our earlier stove models were rejected by the users because they
were about 10 cm taller than the traditional cookstove. So we had to dig a
tunnel beneath the grate and put the grate on ground level in order to
reduce the height of the stove. Even the presence of a chimney is resented
by the users because they have to clean it periodically.
A.D.Karve
-----Original Message-----
From: Stephen Gitonga <stephen.gitonga@UNDP.ORG>
To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
Date: Thursday, February 06, 2003 2:18 AM
Subject: Re: [STOVES] [hedon] Re: Different Types of Energy Saving Stoves In
Southern Malawi

>Dear stovers
>
>A few days ago, there was a message that came through the stovers list
>which touched on the foods that some communities in developing countries
>use. That was quite important because you cannot design a stove without
>knowing what use it will be put to and by who. Based on my own personal
>experience in the area of improved stoves for development, the picture
>is only complete when some of the following
>are included in the stove design (from the users point of view)
>1) Type of foods routinely used by the communities. Some foods cooked by
>communities takes six hours to cook and clay and sand stoves proves
>quite useful in that respect. The mass will take the heat for the first
>30 minutes but later the mass retains the heat within itself as the fire
>is directed to the pot.
>
>This makes it very ideal where the heat is used for house warming as the
>food cooks. Certainly, the stove made that way with a community that
>uses it in that way is far much useful and effective than a three stone
>fire. Let me elaborate on the six hour cooking period. There is the
>heating and boiling period for about 1 and half hours to two hours, then
>there is the heating period and the the
>simmering period. In all these stages of cooking, different feeding of
>firewood to the fire is required. Take an example when cooking matoke
>(steamed bananas in Uganda) for example, you need a steaming period that
>needs very low level of heating and the mass of sand and clay plays a
>great part in achieving the right cooking environment. Dry maize and
>beans (Githeri) in Kenya takes between 5 and 6
>hours to just bring it to the cooking stage. Then it has to be pounded
>which is another 30 minutes to one hour exercise etc. Using that
>example, the samples of stoves posted are far more efficient than use
>of a three stone fire.
>
>2) Length of time the food takes to cook. This is more important as the
>stove efficiency consideration in design.
>3) The type of pot used in the cooking. Many pots used cannot fit very
>well with a situation where heat is to be forced to scrape against the
>sides of the pot. A very unfortunate reality. So other ways of achieving
>some level of efficiency are devised including the stoves posted by
>Christa and Christoph. which are better in the field than the three
>stone fire.
>
>3) Some foods requires pounding as it cooks which influences the way the
>pot has to sit on the stove.
>4) The most forgotten aspects by stove designers is that the fire is
>used by the users for other activities apart from cooking e.g. house
>warming and also warming themselves around the fireplace as they
>socialise, roasting of maize or potatoes, and even in some cases to
>provide light in the kitchen (some kitchens have no lamps) etc. as
>culture demands. Some form of allowance to this is needed if the
>community will adopt the stove fully otherwise they will still make
>another side-fire against the most efficient stove in the kitchen to
>carry out the other functions of the fire place.
>
>After all that has been tackled, the secondary considerations from the
>users point of view include
>1) stove design and its looks: Is the stove appealing to the eye?
>2) affordability or accessibility. Is the stove affordable or can it be
>made easily by the user or a helper?
>3) efficiency: is it helping to save some wood? Sometimes the
>communities have looked for solutions spontaneously to save on wood and
>we have many examples in East Africa. Please also look at some of those
>spontaneous designs at the small booklet that I wrote by the name
>"Appropriate mud stoves in East Africa" sold by ITDG
>Publishing(www.itdg.org) which shows some of those mud stoves practiced
>by
>communities to try to address the woodfuel problem.
>5) durability: They are more interested with something that will last
>for sometime.
>6) portability: The issue of whether the stove could be moved from one
>place to the other is important with some communities.
>
>You will realise that it is only in stove efficiency where the user and
>the developer may find a common ground. But the reality is that common
>ground must be cultivated in all the other aspects if stoves programme
>will be successive.
>
>Now looking at the stoves that were posted by Christa Roth and Christoph
>Messinger, I bet they are based on the consideration of the issues I
>have raised above based on the specific community they are dealing with
>. In that respect they might not be very appealing to somebody focused
>on efficiency alone, but they are the most appropriate for the specific
>community they are dealing with. The stoves
>are based on field experiences and I would assume they have incorporated
>many aspects of the users perspective to try to reconcile the users
>culturally influenced considerations with the stove designers
>consideration. They, therefore, possibly represent the true picture of
>what is practical on the ground to that specific community rather than
>in the laboratory or in research environment. They
>represent the meeting point between theory and practice.
>
>These are my personal views and I hope they will help in the good work
>of finding the true solution to better household cooking in the
>developing world.
>
>Regards
>
>Stephen Gitonga
>
>
>
>
>
>Dean Still wrote:
>
>> Dear Stovers,
>>
>> The clay/sand stoves shown by Christa Roth and Christoph Messinger are,
>> unfortunately, good examples of stoves that have in laboratory tests been
>> shown to use more firewood than three stone fires. Just surrounding the
fire
>> with heavy earthen materials does not raise combustion temperatures. The
>> mass actually lowers combustion temperatures for hours until the stove
body
>> has come up to temperature itself. The heat is diverted from its intended
>> purpose: to cook food. Why heat up hundreds of pounds of stove body when
>> cooking five - ten pounds of food?
>>
>> A three stone fire can be quicker, smokes less, uses less fuel.
>>
>> Clay/sand is not insulation. This was the mistake made by the inventors
of
>> these types of stoves, including Aprovecho. Earthen material was thought
to
>> insulate around the fire but we later realized that good insulation is
>> pockets of air in a lightweight, low conducting material. Naturally
>> available sources include pumice rock, perlite, vermiculite, wood ash,
etc.
>>
>> To improve on the properly operated three stone fire requires an
insulated
>> combustion chamber which can be made from locally available materials as
>> well. Forcing the heat to scrape against the sides of the pot is the true
>> advantage of the good cook stove, improved heat transfer can help to save
>> large percentages of wood. To do this without first cleaning up
combustion
>> in an insulated combustion chamber can create more harmful emissions,
>> however. Both hotter, cleaner combustion and improved heat transfer can
>> easily be designed into a modern, improved ceramic cook stove.
>>
>> I very much do not like being critical of the enthusiastic work of
others.
>> But these types of stoves have been built over and over in the last
twenty
>> years without regard to the careful work of Baldwin, Prasad, Emma George
>> just recently in Uganda, etc. who showed that mass is detrimental to
>> efficient cook stoves. Let's just change the recipe and make the
combustion
>> chambers of these stoves insulative. The stoves will be just as
vernacular
>> but they will do in actuality what was hoped for by designers.
>>
>> All Best,
>>
>> Meaning no offense,
>>
>> Dean Still
>>
>> ----------
>> Does your organisation feature on the Shell Foundation online database?
Take a look at http://ecoharmony.net/hedon/org.php to find out more.
>>
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>>
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>>
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>

From crispin at NEWDAWN.SZ Thu Feb 6 03:10:33 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:12 2004
Subject: Materials for testing
Message-ID: <THU.6.FEB.2003.101033.0200.CRISPIN@NEWDAWN.SZ>

Dear Margaret and Paul

I have checked with Rheem, the biggest can makers in South Africa and their
210 litre drums are available in 0.8, 0.9, 1.15mm wall thicknesses. It is
1.2mm thick for the galvanized version.

I found that in the Sahel there is no other material avilable except car
bodies and parts. The 'forgerons' each have a stash of drums collected from
people importing cooking oil from the south.

Every stove has to be made from that material if it is in a village.

I did get a knife blade cut and hammered from a Peugeot front bumper (chrome
plated so it was white in the end) but everything else including the 'Mali
Stove' is made from oil drums.

It is my understanding that one of the reasons the JIKO stove has a clay
liner, apart from the insulating properties, is to be able to use inferior
sheet metal and still make a functional stove.

Regards
Crispin

++++++++=

Paul wrote:
Although it might sound UN-scientific, use whatever you can find. Or
"whatever can you can find". Remember that "tincanium" is a reality in
some places. People who live day-by-day could easily be using a stove
that might last season-by-season. They use it until it is burned out, and
then get another short-life identical product because that is what they or
neighbors can find, make or purchase at very low costs.

As a university professor, I can suggest that even experiments on products
(sheet metal in this case) that we know will be quickly destroyed will be
useful as learning experiences AND can provide some low-end benchmarks
(points of reference) for comparison with the better and thicker sheet
metals. When you make a graph of the data, you will have some "low-end"
data instead of unknown extrapolations. And you might have some real
surprises in the process. We all await your results.

From crispin at NEWDAWN.SZ Thu Feb 6 10:24:41 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:12 2004
Subject: Collaboration with Tata Energy Research Institute
Message-ID: <THU.6.FEB.2003.172441.0200.CRISPIN@NEWDAWN.SZ>

Dear AD and Tami

It seems to me that the real answer is to change from being an
all-or-nothing clay OR steel stove. There are advantages to the clay which
were mentioned. The advantages of the steel are that if you put a Tsotso or
Shisa stove type grate into a clay stove, you get preheated secondary air
and less heat lost to the clay stove body. The reason for this is that the
secondary air absorbs heat and redirects it to the fire, burning available
primary combustion products.

To me this seems obvious: put a perforated steel liner into the clay stove
with a gap between the liner and the wall, except at the top, and open on
the bottom so air can go up the gap between them.

I call this heat recycling. A heat recycling stove, which our latest one
now called the VESTO is one which captures heat and redirects it to the fire
again. It accomplishes two things: it reduces heat losses to the stove
body, and it geatly enhances combustion at low air flows. Without going to
the complication of getting free-flowing preheated secondary air and
controlled primary air in a clay stove, one can get preheated secondary
secondary air, almost for free, by adding the liner/combustion chamber.

If you all remember when Paul and I were discussing sending a large number
of stoves to Afghanistan, I suggested that we send only the grates because
that is the part which is difficult to lake out of mud, but the rest of the
stove can be amde from clay/soil. The steel/cast iron/sheet metal
combustion chamber is suspended at the top of a tapered hole, the right size
at the top to catch the lip of the grate. It can be any size you like.
Ours is 125mm in diameter. Let the air enter the bottom on one side and put
a rock in it to control the flow. Any arrangement of pots and lids and
doors can be added, three pots in a row if you like.

We should not be afraid to use steel in a clay stove. After all the chimney
is steel, and the pots are metal, so why not a combustion chamber?

Whatever clay stove anyone builds, however efficient or effective, adding a
steel combustion chamber to it so as to provide preheated secondary air will
increase its thermal efficiency, reduce losses and achieve more complete
combustion.

Regards
Crispin

From crispin at NEWDAWN.SZ Thu Feb 6 10:11:26 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:12 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <THU.6.FEB.2003.171126.0200.CRISPIN@NEWDAWN.SZ>

Dear Peter and Kevin

I agree more with Peter on this. The air going up a chimney has the hot
gases component and the warm room air that gets sucked up with it. All that
air comes in through cracks and holes in the windows, doors and walls,
floorboards etc. That is why an open fireplace is so useless at heating up
a room. In the far north a log cabin is only really warm near the fire.

A three stone fire in a room, which also has to have air turnover by leaving
a window open a little, lets out only warm room air, not hot gases at
several hundred degrees, and it does not suck extra air with out. If one
placed the openings in the room to allow in cold air and far away let out
air that had, by the time it got there, cooled a great deal, then the heat
does in fact accumulate in hte room to a far greater extend that it does
when funnelling it up the chinmey.

100%, no, but a great deal higher than 5%. I think the cold air fireplaces
(with glass doors and heat-exchangers) are in the 30% range, no? Not sure,
but they are pretty good.

An in-between solution is to put a hood and chimney (with a flue control
damper to limit air turnover) high over the open fire so the heat has a
chance to dissipate into the room air. These hoods have been shown to
greatly reduce the particulate level, by a large percentage - I think
someone gave us a level on this list last year.

Just about every foreplace in Swaziland is built deep into the wall and
gives off almost no useful heat at all and the flue control is so basic (all
or nothing) that one can't even control the draft. Heats your face and
freezes your butt.

Regards
Crispin

----- Original Message -----
From: Kevin Chisholm <kchisholm@ca.inter.net>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, February 06, 2003 8:06 AM
Subject: Re: [STOVES] [hedon] Re: Different Types of Energy Saving Stoves In
Southern Malawi

Dear Peter
----- Original Message -----
From: "Peter Verhaart" <pverhaart@OPTUSNET.COM.AU>
...del...
> >
> >This makes it very ideal where the heat is used for house warming as the
> >food cooks. Certainly, the stove made that way with a community that
> >uses it in that way is far much useful and effective than a three stone
> >fire.

>A clean burning three sone fire which is also used for space heating has an
efficiency of 100 %. No chimney stove can touch that.
>The net efficiency of a fireplace within a home is about 5%, because of the
gross amount of excess air drawn up the >stack/chimney.

[snip]

From yark at U.WASHINGTON.EDU Thu Feb 6 12:42:09 2003
From: yark at U.WASHINGTON.EDU (Tami Bond)
Date: Tue Aug 10 18:30:12 2004
Subject: Collaboration with Tata Energy Research Institute
In-Reply-To: <000101c2cdd8$5a4fbb80$695e41db@adkarvepn2.vsnl.net.in>
Message-ID: <THU.6.FEB.2003.094209.0800.YARK@U.WASHINGTON.EDU>

Dr. Karve,

> Dear Tami, the fact that the metal model was declared to be non-polluting
> while our clay model was, could be explained by the message from Dean Still
> that just preceded yours on the stovers' group discussion.

Thanks! Can I confirm what I think you're saying
1) The metal stove DOES have a chimney and was found to be non-polluting
2) The clay stoves DO NOT have chimneys and were found to be polluting
3) You believe this is due to the combustion temperature, and keeping the
burning zone of the clay stove hotter will fix the problem.

(And also:)
4) You felt that the clay stoves were less polluting, before you had seen
the measurements?
5) The measurements were made on indoor air concentration?

Thanks again

Tami

From robertoescardo at ARNET.COM.AR Thu Feb 6 13:43:01 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:12 2004
Subject: Stoves for cold climates.
Message-ID: <THU.6.FEB.2003.154301.0300.ROBERTOESCARDO@ARNET.COM.AR>

Mary:
I am working in stoves - home insulation - passive solar in cold climate
areas in the Patagonian Andes and a group in the high - altitude Andes in
Argentina NW is also joining us.
We got some excellent material from the Aga Khan Planning and Building
Services, Pakistan - BUILDING AND CONSTRUCTION IMPROVEMENT PROGRAMME - BACIP
including some about schol design. I got a CD from Mrs. Greta Rana, the
ICIMOD librarian grana@icimod.org.np
Some of the material will be available at Tom Miles website
http://www.trmiles.com/stoves in a few days, thanks to the authorization
that Sjoerd Nienhuys, former BACIP Director, now Senior Renewable Energy
Advisor, SNV/N, Netherlands Development Organisation at Nepal:
snienhuys@snv.org.np. Sjoerd has joined the stoves list.

We have some very preliminary ideas of a Rocket combustion chamber heating -
cooking stove for cold areas, but a lot of development work is ahead and we
think (Sjoen convinced us) that good thermal insulation is the first
priority and we are now focused there.

Really there is not too much info about heating - cooking stoves for cold
areas, I think the best work has been done in China, but I could not find
yet a good point of entry there.

We have had some talks with Dean, Tom and Ron about a "Stoves for cold
climates" group, perhaps it is time to begin. I guess you will be the
perfect group leader.

Kind regards

Roberto Escard?
KUTRALDUM (Making fire in mapungundum, mapuches language)

PS; A recopilation of SP in the Himalayas can be found at Profiting from
Sunshine - Passive Solar Building in the Mountains: Collection of Papers on
National Workshops in China, India, Nepal and Pakistan edited by N.K. Bansal
and Kamal Rijal International Centre for Integrated Mountain Development,
2000. 284 pages, US$20.00. ISBN 92-9115-099-1 You can get it at
http://www.earthprint.com/ but I supposse you will not get there any new for
you.

 

----- Original Message -----
From: "Mary Hancock" < >
To: <ethos@vrac.iastate.edu>
Sent: Thursday, February 06, 2003 11:11 AM
Subject: [ethos] [Fwd: Re: [hedon] Re: Different Types of Energy Saving
Stoves In Southern Malawi]
> > Dear All,
>
> I have been very interested to read of the wealth of experience in
> cooking stove design. I am primarily involved in passive thermal design
> but I have been working on the problem of providing heating for school
> classrooms in Northern Pakistan in the Southern Himalayas where it is
> very cold in the winter for several months. Passive strategies are not
> very effective in the high thermal mass buildings but I have been able
> to find very little development work on effective, safe heaters that
> might spread the heat around the classroom.
> I would appreciate the advice of anyone with experience in this area,
> Mary Hancock
>
>
> --
> Mary Hancock, Architect
> Course Chair Energy Efficient Building MSc and senior technology
> lecturer
>
>

From robertoescardo at ARNET.COM.AR Thu Feb 6 14:16:21 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:12 2004
Subject: Heating stoves
Message-ID: <THU.6.FEB.2003.161621.0300.ROBERTOESCARDO@ARNET.COM.AR>

I strongly agree with Crispin opinion about placing a hood above the fire as
the best in-betwen solution, in fact we are working on it, with a platform
for the fire to have better primary air from below and to colect the ashes
(excelent fertilizer)

One often disregarded fact is that for people in cold climates open fires
have a strong cultural signification, they spend many hours a day in winter,
with a few daylight hours and often cloudy skies, sitting, socializing and
heating appetizers (or hunger cheaters): Ash baked potatoes in the Himalayas
and Peru, brewing mate in our country. Our consulting anthropologist (yes,
really we have one) adviced us about the difficulties of changing these
strong cultural patterns, only making clear to women the burden of desease
posed by open fires is an open path for change.

(Some interesting comments at: http://www.mtnforum.org/apmn/ics1.htm an
e-forum about improved stoves in Mountain Areas held a year ago)

Crispin: As usual you surprised me.

Regards for all

Roberto.

----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, February 06, 2003 12:11 PM
Subject: Re: [STOVES] Different Types of Energy Saving Stoves In Southern
Malawi

> Dear Peter and Kevin
>
> I agree more with Peter on this. The air going up a chimney has the hot
> gases component and the warm room air that gets sucked up with it. All
that
> air comes in through cracks and holes in the windows, doors and walls,
> floorboards etc. That is why an open fireplace is so useless at heating
up
> a room. In the far north a log cabin is only really warm near the fire.
>
> A three stone fire in a room, which also has to have air turnover by
leaving
> a window open a little, lets out only warm room air, not hot gases at
> several hundred degrees, and it does not suck extra air with out. If one
> placed the openings in the room to allow in cold air and far away let out
> air that had, by the time it got there, cooled a great deal, then the heat
> does in fact accumulate in hte room to a far greater extend that it does
> when funnelling it up the chinmey.
>
> 100%, no, but a great deal higher than 5%. I think the cold air
fireplaces
> (with glass doors and heat-exchangers) are in the 30% range, no? Not
sure,
> but they are pretty good.
>
> An in-between solution is to put a hood and chimney (with a flue control
> damper to limit air turnover) high over the open fire so the heat has a
> chance to dissipate into the room air. These hoods have been shown to
> greatly reduce the particulate level, by a large percentage - I think
> someone gave us a level on this list last year.
>
> Just about every foreplace in Swaziland is built deep into the wall and
> gives off almost no useful heat at all and the flue control is so basic
(all
> or nothing) that one can't even control the draft. Heats your face and
> freezes your butt.
>
> Regards
> Crispin
>
> ----- Original Message -----
> From: Kevin Chisholm <kchisholm@ca.inter.net>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Thursday, February 06, 2003 8:06 AM
> Subject: Re: [STOVES] [hedon] Re: Different Types of Energy Saving Stoves
In
> Southern Malawi
>
>
> Dear Peter
> ----- Original Message -----
> From: "Peter Verhaart" <pverhaart@OPTUSNET.COM.AU>
> ...del...
> > >
> > >This makes it very ideal where the heat is used for house warming as
the
> > >food cooks. Certainly, the stove made that way with a community that
> > >uses it in that way is far much useful and effective than a three stone
> > >fire.
>
> >A clean burning three sone fire which is also used for space heating has
an
> efficiency of 100 %. No chimney stove can touch that.
> >The net efficiency of a fireplace within a home is about 5%, because of
the
> gross amount of excess air drawn up the >stack/chimney.
>
> [snip]

From mheat at MHA-NET.ORG Thu Feb 6 14:40:03 2003
From: mheat at MHA-NET.ORG (Norbert Senf)
Date: Tue Aug 10 18:30:12 2004
Subject: Stoves for cold climates.
In-Reply-To: <018301c2ce0f$95f6dc90$0100a8c0@pentium>
Message-ID: <THU.6.FEB.2003.144003.0500.MHEAT@MHANET.ORG>

At 03:43 PM 2003-02-06 -0300, Roberto Escard? wrote:
>(snip)
>Really there is not too much info about heating - cooking stoves for cold
>areas, I think the best work has been done in China, but I could not find
>yet a good point of entry there.

Roberto:

We are involved with high mass heat storing stoves for cold climates
(masonry heaters). They are primarily heating stoves but can have a baking
function included. Our North American trade association has a website at

www.mha-net.org

While they are fairly expensive to construct in North America and Europe,
this is largely due to high labor costs, decorative requirements, and
building code requirements. In principle, they are relatively simple, and a
friend of mine has built one from rammed earth blocks.

They are suitable as radiant heaters, where it is not possible to heat the
air in a whole room, but still desirable to create a comfortable zone, and
might have application in a classroom, for example.

Best ....... Norbert Senf

From tmiles at TRMILES.COM Thu Feb 6 15:17:59 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:12 2004
Subject: Stoves for cold climates.
Message-ID: <THU.6.FEB.2003.121759.0800.TMILES@TRMILES.COM>

I recently had the privilege of enjoying the comfort of a high mass stove in
a small village on the Yenisey river in Siberia. I was told that one member
of the village was particulary skilled at building the stoves, which he
preferred to do rather than logging or fishing. It was more comfortable than
heat from the hot water radiators in the few buildings supplied by the
village district heating plant.

Tom

----- Original Message -----
From: "Norbert Senf" <mheat@MHA-NET.ORG>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, February 06, 2003 11:40 AM
Subject: Re: [STOVES] Stoves for cold climates.

> At 03:43 PM 2003-02-06 -0300, Roberto Escard? wrote:
> >(snip)
> >Really there is not too much info about heating - cooking stoves for cold
> >areas, I think the best work has been done in China, but I could not
find
> >yet a good point of entry there.
>
> Roberto:
>
> We are involved with high mass heat storing stoves for cold climates
> (masonry heaters). They are primarily heating stoves but can have a baking
> function included. Our North American trade association has a website at
>
> www.mha-net.org
>
> While they are fairly expensive to construct in North America and Europe,
> this is largely due to high labor costs, decorative requirements, and
> building code requirements. In principle, they are relatively simple, and
a
> friend of mine has built one from rammed earth blocks.
>
> They are suitable as radiant heaters, where it is not possible to heat the
> air in a whole room, but still desirable to create a comfortable zone, and
> might have application in a classroom, for example.
>
> Best ....... Norbert Senf
>
>

From kchisholm at CA.INTER.NET Thu Feb 6 17:06:14 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:12 2004
Subject: Heating stoves
Message-ID: <THU.6.FEB.2003.180614.0400.KCHISHOLM@CA.INTER.NET>

Dear Roberto
----- Original Message -----
From: "Roberto Escard?" <robertoescardo@ARNET.COM.AR>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, February 06, 2003 3:16 PM
Subject: [STOVES] Heating stoves

> I strongly agree with Crispin opinion about placing a hood above the fire
as
> the best in-betwen solution,

There is no question that the hood will work wonders at capturing "indoor
polluants". However, the hood will do little or nothing directly to improve
the efficiency of the fire. It can have indirect benefits however:

1: The fact that there is a stack vent from the hood virtually eliminates
convective heat loss of teh warm ir above teh lip of the hood, by preventing
it from going out through a hole in teh roof.

2: There will be some convective heating of the room, through the walls of
the flue and the surface of the hood.

in fact we are working on it, with a platform
> for the fire to have better primary air from below and to colect the ashes
> (excelent fertilizer)

If there is a way that you can provide outside air to the fire, then the
fire does not draw warmed air from the room. The advantages of "outside air"
are greater with a less efficient open fire than tehy are with a more
efficient closed fire (ie, a fire in a stove.)
>
> One often disregarded fact is that for people in cold climates open fires
> have a strong cultural signification, they spend many hours a day in
winter,
> with a few daylight hours and often cloudy skies, sitting, socializing and
> heating appetizers (or hunger cheaters): Ash baked potatoes in the
Himalayas
> and Peru, brewing mate in our country.

A stove warms the body, while an open fire warms the Soul.

Our consulting anthropologist (yes,
> really we have one) adviced us about the difficulties of changing these
> strong cultural patterns, only making clear to women the burden of desease
> posed by open fires is an open path for change.

You are wise indeed to recognize the "total requirement package" for your
stove system. I would suggest for your consideration that a hood and stack
are the best single move you could make toward eliminating indoor air
pollution from fires. This will then at least eliminate health
considertions, and allow you to then deal with eficiency considerations.

Kindest regards, and best wishes for success.

Kevin

From dstill at EPUD.NET Thu Feb 6 17:41:17 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:12 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <THU.6.FEB.2003.144117.0800.DSTILL@EPUD.NET>

Dear Christa, Grant, Tom,

I think that while the apparent contradiction between results from
laboratory and field tests has confused a generation of academics and
administrators we can come to an understanding of the situation. The well
operated three stone fire can be very efficient. Tami Bond, then at NOAA, I
think holds the record but many folks have gotten more than 20% of the
energy released from simply burning wood into a pot. I start my semester
classes by holding a contest of three stone fires. These students have
little or no experience making fires and results are generally between 10%
to 20%. When Dr. Larry Winiarski, my mentor and I walked through homes in
the Mexican desert, Larry surprised me by saying right away that the expert
open fire makers were so good at making three stone fires that even a good
stove would not be a great improvement. He suggested we help in some other
way first.

When we use the same laboratory test with the Kenyan improved Jiko, the mud
surround stove like Christa disseminates (a friend made more than 30,000
similar stoves in Togo and built one in our lab to test) or a Aprovecho
designed Lorena type stove, the percentage of heat that makes it into the
pot is less than 20%, usually much less. (See Emma George's report).
http://crest.org/discussiongroups/resources/stoves/George/WoodstovesforUgand
Why does the heavy stove perform worse than the carefully tended open fire?

1.) heat is diverted into the mass of the stove body and lost to the cooking
process
2.) mass cools the fire creating more smoke
3.) neither heat transfer to the pot nor combustion efficiency are improved
in these stoves.

It was this result (twenty years ago) that moved engineers, like Dr.
Winiarski, to move to an insulated "L" shaped combustion chamber (for more
complete combustion) coupled to a insulated skirt that forced heat to scrape
against both the bottom and sides of the pot. This type of stove performs
better than the open fire, saving firewood and reducing smoke in laboratory
tests. Baldwin, Micuta, the Eindhoven group made the same findings available
in their books.

We now know that fired ceramic recipes can include lightweight substances
like vermiculite, perlite, pumice, sawdust, etc. These recipes create
vernacular insulative refractory tiles or bricks that serve well in earthen
stoves. Even floor tiles that are not lightweight can be used as combustion
chambers and then backed up by loose insulation like wood ash, etc.

Earthen stoves can be made from insulative recipes that do not greatly
increase the cost but do help the stove to perform to a higher standard.

When Aprovecho designers went to Honduras in 1997 the cooks there were
adamant that a griddle stove was what they wanted. In fact, cooks did not
even want holes in the griddle in some places because they did not want soot
getting into the kitchen on the pots. The Justa stove that Dr. Winiarski
designed was not an improvement on the three stone fire in laboratory tests.
The Justa stove got only 17% of the heat from the wood into the pot(s).

The same stove but with pots sunken below the griddle had much better heat
transfer to the pots and could get 40% of the heat into the pots. Studying
the three stone fire in part taught engineers how design modern stoves and
it is a good necessary standard against which to judge stoves when they are
being developed.

When the Justa stove is tested in field tests we have been pleasantly
surprised that it saves something like 60% to 70% of the wood that was used
before switching. Why does a stove that is 17% fuel efficient save that much
wood?

The answer I think is apparent to all: a lot of in practice three stone
fires are not made with fuel efficiency as the highest motivation. Also, the
small door into the combustion chamber forces the user to use less wood.
Wood is highly concentrated: 8,600 BTU per pound! A little biomass can cook
a lot of food but three stone fires go out easily and big fires are more
convenient. I'm sure that there are other equally explanative reasons why
not very efficient stoves save biomass.

Certainly, I am glad that stoves don't have to be really great to save this
precious resource. At the same time, making stoves as efficient as possible
must appeal to us all: wood is becoming scarcer and smoke causes illness. So
those in the labs work with those in the field to improve the success of
cooking. And for cooking methods to be successful, cooks ultimately steer
the process, informing both lab and field of their needs.

Insulated combustion chambers make lighting a fire much easier and fires
don't go out as easily. Women in Guatemala like the HELPS stove because it
can make food quickly, no waiting for the heavy combustion chamber to
finally get hot.

We continue to develop more recipes for insulative ceramics. Any assistance
is greatly appreciated.

All Best,

Dean

 

Subject: Re: Re[2]: Different Types of Energy Saving Stoves In Southern
Malawi

>Dear Dean, dear Grant, dear Tom
>As much as I appreciate Deans comments and I also share your views not to
>heat up lots of masses of material, I just wonder how in more than hundred
>public cooking demonstrations where we compared the three-stone-stove with
>the improved portable clay stove, on average the saving of firewood was
>about 62%??? how do you explain that then? that doesnot really fit to your
>arguments, or?
>To get the discussion on a more on a constructive level:
>Tom has already commented on that and taken up the right points (thanks
>Tom!), I just want to add some other points.
>our clay stoves do heat up very quickly, though I cannot tell you in exact
>figures. What I can give as an approximate figure is that our portable clay
>stoves weigh about 3 kg (recommended height of the fire chamber= 18 cm,
>thickness of the wall ca. 3 cm= two fingers), so we are not talking about
>'hundreds of pounds of masss' to heat up.
>I haven't done any scientific lab-test, as first of all I don't have any
>equipment here and secondly I have to admit that I believe more in what the
>experiences of the users in the fields are, and that is monitored by the
>public demonstrations. To me there is still the possibility that something
>can be proven very efficient in a labtest, but then in the field, because
of
>different use of the device, that efficiency is not achieved or realised by
>the user. We have done public demonstrations in 185 villages and of about
>130 villages I have useful and credible reports, the other reports I
>discarded.
>In those public demonstrations we cook with the same type of pot the same
>quantities of the same dish on the two stoves and we give both stoves 10
>sticks of firewood to start with. Those sticks are publicly counted. After
>the cooking the remaining sticks are counted publicly again.
>Normally the 3-stone-stove uses 7-10 sticks, the clay stove only 3. So I
>believe that is not witchcraft, but there is some proven firewood saving,
>for whatever reason.
>So much to the portable clay stove.
>
>I do share your concern about the fixed mud stoves, as there the situation
>is a lot different. Therefore we do encourage people to put in a layer of
>insulating material easily available to them, like a mixture of ashes and
>dry grass or other plant material. This layer is supposed to go about 5 cm
>on the bottom of the stove, and preferrably also on the sides of the stove,
>but this depends on the skills of the one constructing the stoves.
>We do promote more the portable stove and the fixed stove only as an
>alternative in those areas where you can't find suitable pottery clay or
>where people have very big families and do need to cook for more than 15
>people. We demonstrate both types and the choice of the model though is up
>to the people themselves.
>Some families do have both models of stoves and use them for different
>things. to give you figures: The figures that were reported in the last
>counting we did gave in Feburary 2002 gave us about 19.000 portable stoves
>and 4.000 fixed stoves. Some households have up to 4 stoves in use. In
>total we counted around 11.000 households using the stoves regularly, which
>means that in average nearly every household has 2 stoves (however reliable
>figures can be: never trust any statistics that you haven't forged
>yourself... These reports were made by our volunteers in the then 163
>villages and the reports were collected and borught to our office by the
>government field assistants. Last year we dod not have any funds to go into
>a more founded survey and e.g. go out and do spot-checks ourselves.
>I have not done any extended efficiency tests on the fixed stoves, as in
the
>public demonstrations for practical reasons we obviously only use the
>portable ones. From some reports that I got the fixed stoves do prove less
>efficient (I guess around 30% saving), but I don't really have the critical
>mass of figures supporting that. As it is not the main focus of the
>promotion, there has also been no assessment done. Bear in mind, we are a
>food security programme and the stove promotion is only one part in our
food
>processing sector, which is one of 7 sectors of our project. I don't claim
>to be a stove expert (yet). As I myself am not 100% convinced on the fixed
>stoves, I am bit wary of pushing them. I found them introduced when I took
>over the project here.
>Of course in the picture page where the fixed stove is shown, I did not
>mention anything about the way how to construct it and that you should
build
>a layer of insulation in there. That is not a 'how-to-guide' yet and I am
>also not so sure, if we should do one on that type, as we are more
conivnced
>about the portable stove.
>Grant, what do you think? I definitely support the idea on adding a comment
>on that page, that this model shouldn't be the favourite and most promoted
>one. But I would never prevent people from constructing one, after it all,
I
>see our role to give them choices. And some people do have reasons to opt
>for those. They are definitely not the ideal solution, but still better
than
>the 3 stone-stone, as far as our users observe, otherwise they wouldn't go
>for them.
>Grant, could you add a comment to the picture page wher the fixed stove is
>appearing that you think is suitable?
>Dean, What type of insulation do you use in your fixed stoves? I would be
>interested to know more about 'your' stove and very much support the idea
of
>having a 'how-to-guide' available, even on the same website or at least
with
>a link there.
>
>I hope that leads something good.
>Sorry, some other work is waiting as I am still stuck with most of the
>administrative tasks of running our project.
>Looking forward to your comments.
>Christa
>
>PS I just found TOms mail with the website-indication for the AProvecho
>stoves etc. I'll have to wait until the weekend for internet access, so
>can't comment on that now. That makes one of the questions above obsolete.
>
>
>
>
>
>
>
>
>----- Original Message -----
>From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
>To: "Dean Still" <dstill@epud.net>; <STOVES@LISTSERV.REPP.ORG>;
><hedon@yahoogroups.com>
>Cc: "Christa Roth" <messinger.roth@Africa-Online.net>
>Sent: Wednesday, February 05, 2003 9:18 PM
>Subject: Re[2]: Different Types of Energy Saving Stoves In Southern Malawi
>
>
>> Hello Dean,
>>
>> I agree completely with your criticisms of the heavy mass stoves shown
>> in the pictures at www.ecoharmony.net/hedon/malawistoves.php - fuel
>> inefficient and smokey.
>>
>> The clay stove (www.ecoharmony.net/hedon/claystove.php) is, I believe,
>> fuel saving although probably not 'lower smoke emitting' - it is a
>> modification of the ITDG design used in Kenya, which has been
>> carefully tested/monitored over the years. After significant emissions
>> & efficiency testing I did some years ago (www.ecoharmony.com/thesis)
>> I too was skeptical about fuel savings from the clay stoves being
>> disseminated, but have since been shown convincing evidence from ITDG
>> & GTZ. On the emissions front, though, ITDG's recent Indoor Air
>> Quality testing of these devices in use have not shown significant
>> emission reductions - or so I have heard.
>>
>> Your point is still valid - it would certainly be much better to work
>> on and promote insulated, low-mass combustion chambers as you are
>> doing at Aprovecho! Would you be able to draft a similar 'how-to
>> guide' (similar style) on how to make the Rocket Stove. I know you
>> have some information at www.efn.org/~apro/attitlepage.html, but I
>> don't see any step-by-step guidelines which development organisations
>> could follow. Would you be willing to help make one?
>>
>> I will introduce some additional explanation on the existing online
>> how-to guides (Christa - could you help?) so as not to confuse/mislead
>> readers.
>>
>> Thanks for the contribution
>>
>> Grant
>>
>> Wednesday, February 5, 2003, 2:17:07 PM, you wrote:
>>
>> DS> Dear Stovers,
>>
>> DS> The clay/sand stoves shown by Christa Roth and Christoph Messinger
>are,
>> DS> unfortunately, good examples of stoves that have in laboratory tests
>been
>> DS> shown to use more firewood than three stone fires. Just surrounding
>the fire
>> DS> with heavy earthen materials does not raise combustion temperatures.
>The
>> DS> mass actually lowers combustion temperatures for hours until the
stove
>body
>> DS> has come up to temperature itself. The heat is diverted from its
>intended
>> DS> purpose: to cook food. Why heat up hundreds of pounds of stove body
>when
>> DS> cooking five - ten pounds of food?
>>
>
>
>
>

From adkarve at PN2.VSNL.NET.IN Thu Feb 6 22:19:42 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:12 2004
Subject: Collaboration with Tata Energy Research Institute
Message-ID: <FRI.7.FEB.2003.084942.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Tami,
you have misunderstood me. Neither the metal stove nor the clay one had a
chimney. Both are meant for a single pot use. The metal stove is portable.
It is carried outside the house for igniting and when the fire starts
burning brightly, it is brought into the kitchen. One thus avoids filling
the house with smoke while the fire is being lit. The mud stove constructed
by us is stationary, so there is a smoke in the kitchen while one is
lighting the fire, but once it gets going, at least visibly the flame colour
and the quantity of smoke produced by the clay stove are similar to those of
the metal stove. The clay stove has exactly the same internal dimensions as
the metal one. We installed one in the Indian Institute of Technology,
Mumbai, which has all the fancy equipment for measuring CO, particulate
matter and the benzapyrenes etc. As I reported, the IIT researchers told us
that our clay stove was smokey. I feel, that the body of our clay stove
absorbed the heat to a greater extent than the body of the metal stove. As
a result, the temperature within the firebox could have been lower in the
case of the clay stove. However, in spite of the official condemnation, our
clay stove is quite popular among the users and they are demanding it. We
are hesitating to disseminate it because of the adverse report about its
emissions.
A.D.Karve
-----Original Message-----
From: Tami Bond <yark@u.washington.edu>
To: A.D. Karve <adkarve@pn2.vsnl.net.in>
Cc: <STOVES@LISTSERV.REPP.ORG>
Date: Thursday, February 06, 2003 11:11 PM
Subject: Re: [STOVES] Collaboration with Tata Energy Research Institute

>
>Dr. Karve,
>
>> Dear Tami, the fact that the metal model was declared to be non-polluting
>> while our clay model was, could be explained by the message from Dean
Still
>> that just preceded yours on the stovers' group discussion.
>
>Thanks! Can I confirm what I think you're saying
>1) The metal stove DOES have a chimney and was found to be non-polluting
>2) The clay stoves DO NOT have chimneys and were found to be polluting
>3) You believe this is due to the combustion temperature, and keeping the
>burning zone of the clay stove hotter will fix the problem.
>
>(And also:)
>4) You felt that the clay stoves were less polluting, before you had seen
>the measurements?
>5) The measurements were made on indoor air concentration?
>
>Thanks again
>
>Tami
>
>

From crispin at NEWDAWN.SZ Fri Feb 7 02:24:04 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:12 2004
Subject: Collaboration with Tata Energy Research Institute
Message-ID: <FRI.7.FEB.2003.092404.0200.CRISPIN@NEWDAWN.SZ>

Dear AD

>Neither the metal stove nor the clay one had a
>chimney.

Is there a resistance to mixing two 'professions' in your region? I found
in the Sahel that the blacksmiths and the fountrymen never spoke to each
other. The products made by the blacksmiths never had a cast aluminum part,
for example.

If you were to put a steel liner, even unperforated, into the clay stove the
smokey time would be reduced, possibly by a lot, and the efficiency of the
fire will be higher as well because of the inevitable air gap between the
metal and the clay (this presumse you are not trying to get Tsotso-like
secondary injected).

Regards
Crispin

From tmiles at TRMILES.COM Fri Feb 7 04:02:47 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:13 2004
Subject: [hedon] Re: Re[2]: Different Types of Energy Saving Stoves In
Southern Malawi
Message-ID: <FRI.7.FEB.2003.010247.0800.TMILES@TRMILES.COM>

Dean,

Until we reload the Stoves site onto CREST/REPP Emma George's paper "Woodstoves for Uganda" June 2002 is at:
http://www.trmiles.com/stoves/George/WoodstovesforUganda.pdf

Tom

----- Original Message -----
From: Dean Still
To: Christa Roth ; STOVES@LISTSERV.REPP.ORG ; hedon@yahoogroups.com ; ethos
Sent: Thursday, February 06, 2003 2:41 PM
Subject: [hedon] Re: Re[2]: Different Types of Energy Saving Stoves In Southern Malawi

Dear Christa, Grant, Tom,

I think that while the apparent contradiction between results from
laboratory and field tests has confused a generation of academics and
administrators we can come to an understanding of the situation. The well
operated three stone fire can be very efficient. Tami Bond, then at NOAA, I
think holds the record but many folks have gotten more than 20% of the
energy released from simply burning wood into a pot. I start my semester
classes by holding a contest of three stone fires. These students have
little or no experience making fires and results are generally between 10%
to 20%. When Dr. Larry Winiarski, my mentor and I walked through homes in
the Mexican desert, Larry surprised me by saying right away that the expert
open fire makers were so good at making three stone fires that even a good
stove would not be a great improvement. He suggested we help in some other
way first.

When we use the same laboratory test with the Kenyan improved Jiko, the mud
surround stove like Christa disseminates (a friend made more than 30,000
similar stoves in Togo and built one in our lab to test) or a Aprovecho
designed Lorena type stove, the percentage of heat that makes it into the
pot is less than 20%, usually much less. (See Emma George's report).
http://crest.org/discussiongroups/resources/stoves/George/WoodstovesforUgand
Why does the heavy stove perform worse than the carefully tended open fire?

1.) heat is diverted into the mass of the stove body and lost to the cooking
process
2.) mass cools the fire creating more smoke
3.) neither heat transfer to the pot nor combustion efficiency are improved
in these stoves.

It was this result (twenty years ago) that moved engineers, like Dr.
Winiarski, to move to an insulated "L" shaped combustion chamber (for more
complete combustion) coupled to a insulated skirt that forced heat to scrape
against both the bottom and sides of the pot. This type of stove performs
better than the open fire, saving firewood and reducing smoke in laboratory
tests. Baldwin, Micuta, the Eindhoven group made the same findings available
in their books.

We now know that fired ceramic recipes can include lightweight substances
like vermiculite, perlite, pumice, sawdust, etc. These recipes create
vernacular insulative refractory tiles or bricks that serve well in earthen
stoves. Even floor tiles that are not lightweight can be used as combustion
chambers and then backed up by loose insulation like wood ash, etc.

Earthen stoves can be made from insulative recipes that do not greatly
increase the cost but do help the stove to perform to a higher standard.

When Aprovecho designers went to Honduras in 1997 the cooks there were
adamant that a griddle stove was what they wanted. In fact, cooks did not
even want holes in the griddle in some places because they did not want soot
getting into the kitchen on the pots. The Justa stove that Dr. Winiarski
designed was not an improvement on the three stone fire in laboratory tests.
The Justa stove got only 17% of the heat from the wood into the pot(s).

The same stove but with pots sunken below the griddle had much better heat
transfer to the pots and could get 40% of the heat into the pots. Studying
the three stone fire in part taught engineers how design modern stoves and
it is a good necessary standard against which to judge stoves when they are
being developed.

When the Justa stove is tested in field tests we have been pleasantly
surprised that it saves something like 60% to 70% of the wood that was used
before switching. Why does a stove that is 17% fuel efficient save that much
wood?

The answer I think is apparent to all: a lot of in practice three stone
fires are not made with fuel efficiency as the highest motivation. Also, the
small door into the combustion chamber forces the user to use less wood.
Wood is highly concentrated: 8,600 BTU per pound! A little biomass can cook
a lot of food but three stone fires go out easily and big fires are more
convenient. I'm sure that there are other equally explanative reasons why
not very efficient stoves save biomass.

Certainly, I am glad that stoves don't have to be really great to save this
precious resource. At the same time, making stoves as efficient as possible
must appeal to us all: wood is becoming scarcer and smoke causes illness. So
those in the labs work with those in the field to improve the success of
cooking. And for cooking methods to be successful, cooks ultimately steer
the process, informing both lab and field of their needs.

Insulated combustion chambers make lighting a fire much easier and fires
don't go out as easily. Women in Guatemala like the HELPS stove because it
can make food quickly, no waiting for the heavy combustion chamber to
finally get hot.

We continue to develop more recipes for insulative ceramics. Any assistance
is greatly appreciated.

All Best,

Dean

 

Subject: Re: Re[2]: Different Types of Energy Saving Stoves In Southern
Malawi

>Dear Dean, dear Grant, dear Tom
>As much as I appreciate Deans comments and I also share your views not to
>heat up lots of masses of material, I just wonder how in more than hundred
>public cooking demonstrations where we compared the three-stone-stove with
>the improved portable clay stove, on average the saving of firewood was
>about 62%??? how do you explain that then? that doesnot really fit to your
>arguments, or?
>To get the discussion on a more on a constructive level:
>Tom has already commented on that and taken up the right points (thanks
>Tom!), I just want to add some other points.
>our clay stoves do heat up very quickly, though I cannot tell you in exact
>figures. What I can give as an approximate figure is that our portable clay
>stoves weigh about 3 kg (recommended height of the fire chamber= 18 cm,
>thickness of the wall ca. 3 cm= two fingers), so we are not talking about
>'hundreds of pounds of masss' to heat up.
>I haven't done any scientific lab-test, as first of all I don't have any
>equipment here and secondly I have to admit that I believe more in what the
>experiences of the users in the fields are, and that is monitored by the
>public demonstrations. To me there is still the possibility that something
>can be proven very efficient in a labtest, but then in the field, because
of
>different use of the device, that efficiency is not achieved or realised by
>the user. We have done public demonstrations in 185 villages and of about
>130 villages I have useful and credible reports, the other reports I
>discarded.
>In those public demonstrations we cook with the same type of pot the same
>quantities of the same dish on the two stoves and we give both stoves 10
>sticks of firewood to start with. Those sticks are publicly counted. After
>the cooking the remaining sticks are counted publicly again.
>Normally the 3-stone-stove uses 7-10 sticks, the clay stove only 3. So I
>believe that is not witchcraft, but there is some proven firewood saving,
>for whatever reason.
>So much to the portable clay stove.
>
>I do share your concern about the fixed mud stoves, as there the situation
>is a lot different. Therefore we do encourage people to put in a layer of
>insulating material easily available to them, like a mixture of ashes and
>dry grass or other plant material. This layer is supposed to go about 5 cm
>on the bottom of the stove, and preferrably also on the sides of the stove,
>but this depends on the skills of the one constructing the stoves.
>We do promote more the portable stove and the fixed stove only as an
>alternative in those areas where you can't find suitable pottery clay or
>where people have very big families and do need to cook for more than 15
>people. We demonstrate both types and the choice of the model though is up
>to the people themselves.
>Some families do have both models of stoves and use them for different
>things. to give you figures: The figures that were reported in the last
>counting we did gave in Feburary 2002 gave us about 19.000 portable stoves
>and 4.000 fixed stoves. Some households have up to 4 stoves in use. In
>total we counted around 11.000 households using the stoves regularly, which
>means that in average nearly every household has 2 stoves (however reliable
>figures can be: never trust any statistics that you haven't forged
>yourself... These reports were made by our volunteers in the then 163
>villages and the reports were collected and borught to our office by the
>government field assistants. Last year we dod not have any funds to go into
>a more founded survey and e.g. go out and do spot-checks ourselves.
>I have not done any extended efficiency tests on the fixed stoves, as in
the
>public demonstrations for practical reasons we obviously only use the
>portable ones. From some reports that I got the fixed stoves do prove less
>efficient (I guess around 30% saving), but I don't really have the critical
>mass of figures supporting that. As it is not the main focus of the
>promotion, there has also been no assessment done. Bear in mind, we are a
>food security programme and the stove promotion is only one part in our
food
>processing sector, which is one of 7 sectors of our project. I don't claim
>to be a stove expert (yet). As I myself am not 100% convinced on the fixed
>stoves, I am bit wary of pushing them. I found them introduced when I took
>over the project here.
>Of course in the picture page where the fixed stove is shown, I did not
>mention anything about the way how to construct it and that you should
build
>a layer of insulation in there. That is not a 'how-to-guide' yet and I am
>also not so sure, if we should do one on that type, as we are more
conivnced
>about the portable stove.
>Grant, what do you think? I definitely support the idea on adding a comment
>on that page, that this model shouldn't be the favourite and most promoted
>one. But I would never prevent people from constructing one, after it all,
I
>see our role to give them choices. And some people do have reasons to opt
>for those. They are definitely not the ideal solution, but still better
than
>the 3 stone-stone, as far as our users observe, otherwise they wouldn't go
>for them.
>Grant, could you add a comment to the picture page wher the fixed stove is
>appearing that you think is suitable?
>Dean, What type of insulation do you use in your fixed stoves? I would be
>interested to know more about 'your' stove and very much support the idea
of
>having a 'how-to-guide' available, even on the same website or at least
with
>a link there.
>
>I hope that leads something good.
>Sorry, some other work is waiting as I am still stuck with most of the
>administrative tasks of running our project.
>Looking forward to your comments.
>Christa
>
>PS I just found TOms mail with the website-indication for the AProvecho
>stoves etc. I'll have to wait until the weekend for internet access, so
>can't comment on that now. That makes one of the questions above obsolete.
>
>
>
>
>
>
>
>
>----- Original Message -----
>From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
>To: "Dean Still" <dstill@epud.net>; <STOVES@LISTSERV.REPP.ORG>;
><hedon@yahoogroups.com>
>Cc: "Christa Roth" <messinger.roth@Africa-Online.net>
>Sent: Wednesday, February 05, 2003 9:18 PM
>Subject: Re[2]: Different Types of Energy Saving Stoves In Southern Malawi
>
>
>> Hello Dean,
>>
>> I agree completely with your criticisms of the heavy mass stoves shown
>> in the pictures at www.ecoharmony.net/hedon/malawistoves.php - fuel
>> inefficient and smokey.
>>
>> The clay stove (www.ecoharmony.net/hedon/claystove.php) is, I believe,
>> fuel saving although probably not 'lower smoke emitting' - it is a
>> modification of the ITDG design used in Kenya, which has been
>> carefully tested/monitored over the years. After significant emissions
>> & efficiency testing I did some years ago (www.ecoharmony.com/thesis)
>> I too was skeptical about fuel savings from the clay stoves being
>> disseminated, but have since been shown convincing evidence from ITDG
>> & GTZ. On the emissions front, though, ITDG's recent Indoor Air
>> Quality testing of these devices in use have not shown significant
>> emission reductions - or so I have heard.
>>
>> Your point is still valid - it would certainly be much better to work
>> on and promote insulated, low-mass combustion chambers as you are
>> doing at Aprovecho! Would you be able to draft a similar 'how-to
>> guide' (similar style) on how to make the Rocket Stove. I know you
>> have some information at www.efn.org/~apro/attitlepage.html, but I
>> don't see any step-by-step guidelines which development organisations
>> could follow. Would you be willing to help make one?
>>
>> I will introduce some additional explanation on the existing online
>> how-to guides (Christa - could you help?) so as not to confuse/mislead
>> readers.
>>
>> Thanks for the contribution
>>
>> Grant
>>
>> Wednesday, February 5, 2003, 2:17:07 PM, you wrote:
>>
>> DS> Dear Stovers,
>>
>> DS> The clay/sand stoves shown by Christa Roth and Christoph Messinger
>are,
>> DS> unfortunately, good examples of stoves that have in laboratory tests
>been
>> DS> shown to use more firewood than three stone fires. Just surrounding
>the fire
>> DS> with heavy earthen materials does not raise combustion temperatures.
>The
>> DS> mass actually lowers combustion temperatures for hours until the
stove
>body
>> DS> has come up to temperature itself. The heat is diverted from its
>intended
>> DS> purpose: to cook food. Why heat up hundreds of pounds of stove body
>when
>> DS> cooking five - ten pounds of food?
>>
>
>
>
>

----------
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From jeff.forssell at CFL.SE Fri Feb 7 04:15:32 2003
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:30:13 2004
Subject: Stoves for cold climates. (Sweden & China)
Message-ID: <FRI.7.FEB.2003.101532.0100.JEFF.FORSSELL@CFL.SE>

In sweden the emerging industrial period lead to a great need for charcoal
for the iron industry (cannons etc) and the king started an investigation
for saving wood. It wound up implementing the "kakelugn" which is a massive
heater with circuitous smoke channels. (I think it was inspired by some
Russian variant) Make a roaring fire which burns efficiently at high temp,
can also give some light as the mass heats. Close the damper when it burns
out and the heated body radiates through the night. I have used them and
they work well.

Another variant is the kang, a brick bed which is common in Northern China.
The high (70 cm ?) masonry bed (they like firm beds apparently!) has a small
fireplace at floor level and the smoke channel loops around under the bed
before going to the chimney. Nice to have heat from below!

Jeff Forssell (tv? s)
SWEDISH AGENCY FOR FLEXIBLE LEARNING (CFL)
Box 3024
SE-871 03 H?RN?SAND /Sweden

<http://www.cfl.se/english/index.htm>
+46(0)611-55 79 48 (Work) +46(0)611-55 79 80 (Fax Work)
+46(0)611-22 1 44 (Home) ( mobil: 070- 35 80 306; [070-4091514])

residence:
Gamla Karlebyv?gen 14 / SE-871 33 H?rn?sand /Sweden

e-mail: every workday: jeff.forssell@cfl.se <mailto:jeff.forssell@cfl.se>
(travel, visiting: jeff_forssell@hotmail.com & MSMessenger)

Personal homepage: <http://www.torget.se/users/i/iluhya/index.htm>
My village technology page: http://home.bip.net/jeff.forssell

Instant messengers Odigo 792701 (ICQ: 55800587; NM/MSM use hotmail address)

From lanny at ROMAN.NET Sat Feb 8 22:27:44 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:13 2004
Subject: Simple Camp Stove Mod #6
Message-ID: <SAT.8.FEB.2003.192744.0800.LANNY@ROMAN.NET>

http://www.lanny.us/cs6.html
aprox 200K

Dear stove friends,
I have a new stove. Simple Camp Stove #6. It is similar to #4 except it has
a new burner deign that creates a circular fame path.
http://www.lanny.us/cs6e.jpg 26K.
I like this stove! It flows better than #4 and handles a larger fire without
smoking. One problem though is that I forgot to wrap the pot convection
sleeve with insulation, so more heat is escaping through the sleeve and out
the stove body than #4. I will correct that with #6b. One thing that I like
about this basic stove design is that is easy and quick to build.
I will post cooking and efficiency test soon on page two.
Lanny

From tmiles at TRMILES.COM Sat Feb 8 21:31:03 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:13 2004
Subject: Simple Camp Stove Mod #6
Message-ID: <SAT.8.FEB.2003.183103.0800.TMILES@TRMILES.COM>

Lanny,

Do you have access to a combustion analyzer so that you can measure CO, O2,
and CO2 in and around your stove?

You have aded a lot of combustion control to your stove. I'd be interested
to know what the range of difference in combustion products is as you adjust
primary and secondary air, etc.

Tom

----- Original Message -----
From: "Lanny Henson" <lanny@ROMAN.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, February 08, 2003 7:27 PM
Subject: [STOVES] Simple Camp Stove Mod #6

> http://www.lanny.us/cs6.html
> aprox 200K
>
> Dear stove friends,
> I have a new stove. Simple Camp Stove #6. It is similar to #4 except it
has
> a new burner deign that creates a circular fame path.
> http://www.lanny.us/cs6e.jpg 26K.
> I like this stove! It flows better than #4 and handles a larger fire
without
> smoking. One problem though is that I forgot to wrap the pot convection
> sleeve with insulation, so more heat is escaping through the sleeve and
out
> the stove body than #4. I will correct that with #6b. One thing that I
like
> about this basic stove design is that is easy and quick to build.
> I will post cooking and efficiency test soon on page two.
> Lanny
>
>

From crispin at NEWDAWN.SZ Sun Feb 9 09:09:31 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:13 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <SUN.9.FEB.2003.160931.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

This is a letter that appears to have missing last December. In view of the
3 stone fire discussion it seems relevant now to repeat it, edited a bit.
- Crispin

++++++++++

Dear Stovers

I have heard from Vivienne in Polekwane, Limpopo (Pietersburg, Northern
Province to you oldsters) about the testing that went on in a rural area
near town.

They tested our Shisa Stove which they called the Swazi Stove. They also had
a Mali stove modified to accept local pots (far bigger firebox apparently),
a Rocket Stove and the 2-pot stainless steel EcoStove made by Scott that was
shown at the Summit in JHB.

The Eco stove was pretty efficient. It has a Rocket Stove firebox on it and
two pots + and oven. It was the only one that came close to the efficiency
of the Shisa Stove. That was for one pot only. The second pot would not
boil although it did get hot. They also baked something but she says the
fuel consumption went way up when they tried. That isn't something I
noticed when I tested it here in Swaziland. It took 30 minutes to get the
oven to temperature (!) and she described the efficiency as 'low'. Perhaps
it was overloaded with fuel though that seems unlikely. The Eco is a
stainless steel stove which costs about $50 to make as far as I hear.

The Rocket Stove used about 1.5 to 2 times as much fuel to cook a meal as
the Shisa Stove. We all know it is pretty clean burning. No surprise there
but for some reason it isn't getting efficiency it could, I think.

The modified Mali stove apparently was a failure and was not tested much.

They also used a 3 stove fire, outdoors, to cook a whole meal, several with
each stove. The meals were a stew and maize porridge in two pots either
cooked together or in sequence.

The Swazi Stove used about 1/3 of the wood of a three stove fire. A variety
of pots were tried and apparently it was not that 'scientific' in its
approach so the direct comparisons are perhaps not all that valid. It was
supposed to be an acceptability test, not a lab rating.

The fuel used in the Swazi Stove was 100mm pieces of 60mm diameter wood of
different types but probably acacias. They settled on using one chunk to
simmer and 2 to boil. They report the control over the power output was
significant. They ran it wide open, the went to 1/2 air and then low air to
simmer. That stove does not have separate control for the secondary air
like the Vesto (see www.newdawn-engineering.com under stoves/ single stoves/
Vesto.

They ran 4 tests (cooked 4 meals) on the Swazi Stove which consumed 1.2 kg
on the first go round, then 1 kg, then 0.84 kg, then 0.8 kg of wood. She
said that as they got used to using it they could make better decisions
about when to add fuel and how much, so they used less wood the more
experience they got (it was their first time to use a stove like this).
When they put in too much wood so that it touched the bottom of the pot, it
smoked. Otherwise it was well
behaved.

The Swazi Stove produced between significantly less charcoal than the other
stoves - about 1/4 as much, usually leaving 20 to as much as 40 grams. The
others were 100gm +. The reason for this is controllable air so that in the
beginning you can make charcoal and at the end you can burn it. The
preheated primary air also keeps the charcoal going for longer.

They cooked one pot of water (2 litres) using dung only, bottom lit. It
reached a rolling boil in "less than 10 minutes" at full power at which time
they turned down the heat and let it simmer for another 20 minutes. A rough
calculation of the efficiency shows it to be something like 33% burning
dung.

The efficiency of a dung fire can be from less than 5% to /perhaps/ 9 or 10%
if it is very well managed. This is a remarkable increase for such a lowly
regarded fuel. Two elderly ladies were impressed no end by the dung fire as
they knew very well what the fuel was normally like. It did not smoke at
any stage during the firing.

The next task is to get some high quality emission and efficiency tests done
in a lab. This is apparently taking place in Germany in February.

Regards
Crispin

From tmiles at TRMILES.COM Sun Feb 9 12:11:09 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:13 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <SUN.9.FEB.2003.091109.0800.TMILES@TRMILES.COM>

Crispin,

Thanks for reposting that message. That must have been the one that brought
the whole server down and put us in the dark for two months. :-)

Can we learn something more about the emissions and efficiency tests that
are to be done in a lab? Methods? Results from other tests?

Thanks

Tom

 

----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>

> The next task is to get some high quality emission and efficiency tests
done
> in a lab. This is apparently taking place in Germany in February.
>
> Regards
> Crispin
>

From dstill at EPUD.NET Sat Feb 8 06:51:19 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:13 2004
Subject: stove fuel efficiency
Message-ID: <SAT.8.FEB.2003.035119.0800.DSTILL@EPUD.NET>

Dear Friends,

I've been doing some reading lately about stove testing. Although stoves are
complicated, and testing perhaps as complicated, I wonder if fuel efficiency
is determined by conditions that can be simply stated. Starting with the
following can we come up with a statement that helps to direct effort and
analysis?

The most fuel efficient cooking stove changes all burning biomass into the
highest temperature heat which then contacts the greatest percentage of the
pot's surface area.

I guess that Time should be included but I wonder if most all stoves have
pretty similar flow rates, not enough difference to bother a Rule of
Thumb?...

Unless the pot is very close to the flames, say 5" maximum distance, heat
transfer is almost totally convective?

Best,

Dean

From crispin at NEWDAWN.SZ Sun Feb 9 17:14:25 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:13 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <MON.10.FEB.2003.001425.0200.CRISPIN@NEWDAWN.SZ>

Dear Tom

No results from Germany yet on the stove emissions.

It will look good it they build small fires in it.

Regards
Crispin

From lanny at ROMAN.NET Sun Feb 9 21:00:24 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod #6
Message-ID: <SUN.9.FEB.2003.180024.0800.LANNY@ROMAN.NET>

Dear Tom,
I only have a co tester but I usually just go by the clearness of the
exhaust.
When testing emissions we should test the concentration of the combustion
products in the exhaust and the volume of the exhaust, right?
If so how do you measure the volume of the exhaust without interfering with
the flow?
Lanny

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, February 08, 2003 6:31 PM
Subject: Re: [STOVES] Simple Camp Stove Mod #6

> Lanny,
>
> Do you have access to a combustion analyzer so that you can measure CO,
O2,
> and CO2 in and around your stove?
>
> You have aded a lot of combustion control to your stove. I'd be interested
> to know what the range of difference in combustion products is as you
adjust
> primary and secondary air, etc.
>
> Tom
>
> ----- Original Message -----
> From: "Lanny Henson" <lanny@ROMAN.NET>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Saturday, February 08, 2003 7:27 PM
> Subject: [STOVES] Simple Camp Stove Mod #6
>
>
> > http://www.lanny.us/cs6.html
> > aprox 200K
> >
> > Dear stove friends,
> > I have a new stove. Simple Camp Stove #6. It is similar to #4 except it
> has
> > a new burner deign that creates a circular fame path.
> > http://www.lanny.us/cs6e.jpg 26K.
> > I like this stove! It flows better than #4 and handles a larger fire
> without
> > smoking. One problem though is that I forgot to wrap the pot convection
> > sleeve with insulation, so more heat is escaping through the sleeve and
> out
> > the stove body than #4. I will correct that with #6b. One thing that I
> like
> > about this basic stove design is that is easy and quick to build.
> > I will post cooking and efficiency test soon on page two.
> > Lanny
> >
> >
>

From tmiles at TRMILES.COM Sun Feb 9 19:08:36 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod
#6
Message-ID: <SUN.9.FEB.2003.160836.0800.TMILES@TRMILES.COM>

Lanny,

I would ignore the volume measurements and let a lab that is set up to
capture volume do that. If you were in a laboratory in Germany testing
Crispin's Shisa stove you would probably use the procedures in DIN 18891.
Norbert Senf and the Masonry Heater Association folks are most familiar with
the different methods for testing. (See Edvark Karlsvik's comparison of the
different laboratory methods on the MHA site at:
http://mha-net.org/docs/karlsvik.PDF )

For development and tuning purposes you are really most interested in the
effect of your air and fuel adjustments on temperature at the work (pot or
plancha) and CO and O2 emissions in the stack. Find the combination of
firing rate (wood feed), and air adjustment (overfire, underfire) that gives
you the lowest average CO under different load (boiling water, etc)
conditions. You'll find that CO will jump all over the map but after a while
you'll get a feel for it. Check the gas conditions around the pot and in the
stack. It would be interesting to see what CO you get after the stove has
heated up and when you're burning mostly char.

I'm hoping that discussion on the list will lead to some commonly adopted
methods for cook stoves testing for combustion efficiency, heating
efficiency, cooking efficiency and emissions.

Tom

----- Original Message -----
From: "Lanny Henson" <lanny@ROMAN.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, February 09, 2003 6:00 PM
Subject: [STOVES] Emission testing question /Re: [STOVES] Simple Camp Stove
Mod #6

> Dear Tom,
> I only have a co tester but I usually just go by the clearness of the
> exhaust.
> When testing emissions we should test the concentration of the combustion
> products in the exhaust and the volume of the exhaust, right?
> If so how do you measure the volume of the exhaust without interfering
with
> the flow?
> Lanny

From tombreed at ATTBI.COM Sun Feb 9 11:45:25 2003
From: tombreed at ATTBI.COM (Tom Reed)
Date: Tue Aug 10 18:30:13 2004
Subject: [ethos] Re: [hedon] Re: Re[2]: Different Types of Energy
Saving Stoves In Southern Malawi
Message-ID: <SUN.9.FEB.2003.094525.0700.TOMBREED@ATTBI.COM>

Dear STOVES, Tom and All:

I visited the site below and thought it was the best summary of responsible stove testing I have seen.

I also noticed that the metal stove excelled in all categories. I hope we could get our woodgas stove into their test queue sometime. We are currently in production of 100 of our Model 800 stoves.

TOM REED BEF STOVEWORKS

Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
----- Original Message -----
From: Tom Miles
To: STOVES@LISTSERV.REPP.ORG ; hedon@yahoogroups.com ; ethos
Cc: Christa Roth
Sent: Friday, February 07, 2003 2:02 AM
Subject: [ethos] Re: [hedon] Re: Re[2]: Different Types of Energy Saving Stoves In Southern Malawi

Dean,

Until we reload the Stoves site onto CREST/REPP Emma George's paper "Woodstoves for Uganda" June 2002 is at:
http://www.trmiles.com/stoves/George/WoodstovesforUganda.pdf

Tom

----- Original Message -----
From: Dean Still
To: Christa Roth ; STOVES@LISTSERV.REPP.ORG ; hedon@yahoogroups.com ; ethos
Sent: Thursday, February 06, 2003 2:41 PM
Subject: [hedon] Re: Re[2]: Different Types of Energy Saving Stoves In Southern Malawi

Dear Christa, Grant, Tom,

I think that while the apparent contradiction between results from
laboratory and field tests has confused a generation of academics and
administrators we can come to an understanding of the situation. The well
operated three stone fire can be very efficient. Tami Bond, then at NOAA, I
think holds the record but many folks have gotten more than 20% of the
energy released from simply burning wood into a pot. I start my semester
classes by holding a contest of three stone fires. These students have
little or no experience making fires and results are generally between 10%
to 20%. When Dr. Larry Winiarski, my mentor and I walked through homes in
the Mexican desert, Larry surprised me by saying right away that the expert
open fire makers were so good at making three stone fires that even a good
stove would not be a great improvement. He suggested we help in some other
way first.

When we use the same laboratory test with the Kenyan improved Jiko, the mud
surround stove like Christa disseminates (a friend made more than 30,000
similar stoves in Togo and built one in our lab to test) or a Aprovecho
designed Lorena type stove, the percentage of heat that makes it into the
pot is less than 20%, usually much less. (See Emma George's report).
http://crest.org/discussiongroups/resources/stoves/George/WoodstovesforUgand
Why does the heavy stove perform worse than the carefully tended open fire?

1.) heat is diverted into the mass of the stove body and lost to the cooking
process
2.) mass cools the fire creating more smoke
3.) neither heat transfer to the pot nor combustion efficiency are improved
in these stoves.

It was this result (twenty years ago) that moved engineers, like Dr.
Winiarski, to move to an insulated "L" shaped combustion chamber (for more
complete combustion) coupled to a insulated skirt that forced heat to scrape
against both the bottom and sides of the pot. This type of stove performs
better than the open fire, saving firewood and reducing smoke in laboratory
tests. Baldwin, Micuta, the Eindhoven group made the same findings available
in their books.

We now know that fired ceramic recipes can include lightweight substances
like vermiculite, perlite, pumice, sawdust, etc. These recipes create
vernacular insulative refractory tiles or bricks that serve well in earthen
stoves. Even floor tiles that are not lightweight can be used as combustion
chambers and then backed up by loose insulation like wood ash, etc.

Earthen stoves can be made from insulative recipes that do not greatly
increase the cost but do help the stove to perform to a higher standard.

When Aprovecho designers went to Honduras in 1997 the cooks there were
adamant that a griddle stove was what they wanted. In fact, cooks did not
even want holes in the griddle in some places because they did not want soot
getting into the kitchen on the pots. The Justa stove that Dr. Winiarski
designed was not an improvement on the three stone fire in laboratory tests.
The Justa stove got only 17% of the heat from the wood into the pot(s).

The same stove but with pots sunken below the griddle had much better heat
transfer to the pots and could get 40% of the heat into the pots. Studying
the three stone fire in part taught engineers how design modern stoves and
it is a good necessary standard against which to judge stoves when they are
being developed.

When the Justa stove is tested in field tests we have been pleasantly
surprised that it saves something like 60% to 70% of the wood that was used
before switching. Why does a stove that is 17% fuel efficient save that much
wood?

The answer I think is apparent to all: a lot of in practice three stone
fires are not made with fuel efficiency as the highest motivation. Also, the
small door into the combustion chamber forces the user to use less wood.
Wood is highly concentrated: 8,600 BTU per pound! A little biomass can cook
a lot of food but three stone fires go out easily and big fires are more
convenient. I'm sure that there are other equally explanative reasons why
not very efficient stoves save biomass.

Certainly, I am glad that stoves don't have to be really great to save this
precious resource. At the same time, making stoves as efficient as possible
must appeal to us all: wood is becoming scarcer and smoke causes illness. So
those in the labs work with those in the field to improve the success of
cooking. And for cooking methods to be successful, cooks ultimately steer
the process, informing both lab and field of their needs.

Insulated combustion chambers make lighting a fire much easier and fires
don't go out as easily. Women in Guatemala like the HELPS stove because it
can make food quickly, no waiting for the heavy combustion chamber to
finally get hot.

We continue to develop more recipes for insulative ceramics. Any assistance
is greatly appreciated.

All Best,

Dean

 

Subject: Re: Re[2]: Different Types of Energy Saving Stoves In Southern
Malawi

>Dear Dean, dear Grant, dear Tom
>As much as I appreciate Deans comments and I also share your views not to
>heat up lots of masses of material, I just wonder how in more than hundred
>public cooking demonstrations where we compared the three-stone-stove with
>the improved portable clay stove, on average the saving of firewood was
>about 62%??? how do you explain that then? that doesnot really fit to your
>arguments, or?
>To get the discussion on a more on a constructive level:
>Tom has already commented on that and taken up the right points (thanks
>Tom!), I just want to add some other points.
>our clay stoves do heat up very quickly, though I cannot tell you in exact
>figures. What I can give as an approximate figure is that our portable clay
>stoves weigh about 3 kg (recommended height of the fire chamber= 18 cm,
>thickness of the wall ca. 3 cm= two fingers), so we are not talking about
>'hundreds of pounds of masss' to heat up.
>I haven't done any scientific lab-test, as first of all I don't have any
>equipment here and secondly I have to admit that I believe more in what the
>experiences of the users in the fields are, and that is monitored by the
>public demonstrations. To me there is still the possibility that something
>can be proven very efficient in a labtest, but then in the field, because
of
>different use of the device, that efficiency is not achieved or realised by
>the user. We have done public demonstrations in 185 villages and of about
>130 villages I have useful and credible reports, the other reports I
>discarded.
>In those public demonstrations we cook with the same type of pot the same
>quantities of the same dish on the two stoves and we give both stoves 10
>sticks of firewood to start with. Those sticks are publicly counted. After
>the cooking the remaining sticks are counted publicly again.
>Normally the 3-stone-stove uses 7-10 sticks, the clay stove only 3. So I
>believe that is not witchcraft, but there is some proven firewood saving,
>for whatever reason.
>So much to the portable clay stove.
>
>I do share your concern about the fixed mud stoves, as there the situation
>is a lot different. Therefore we do encourage people to put in a layer of
>insulating material easily available to them, like a mixture of ashes and
>dry grass or other plant material. This layer is supposed to go about 5 cm
>on the bottom of the stove, and preferrably also on the sides of the stove,
>but this depends on the skills of the one constructing the stoves.
>We do promote more the portable stove and the fixed stove only as an
>alternative in those areas where you can't find suitable pottery clay or
>where people have very big families and do need to cook for more than 15
>people. We demonstrate both types and the choice of the model though is up
>to the people themselves.
>Some families do have both models of stoves and use them for different
>things. to give you figures: The figures that were reported in the last
>counting we did gave in Feburary 2002 gave us about 19.000 portable stoves
>and 4.000 fixed stoves. Some households have up to 4 stoves in use. In
>total we counted around 11.000 households using the stoves regularly, which
>means that in average nearly every household has 2 stoves (however reliable
>figures can be: never trust any statistics that you haven't forged
>yourself... These reports were made by our volunteers in the then 163
>villages and the reports were collected and borught to our office by the
>government field assistants. Last year we dod not have any funds to go into
>a more founded survey and e.g. go out and do spot-checks ourselves.
>I have not done any extended efficiency tests on the fixed stoves, as in
the
>public demonstrations for practical reasons we obviously only use the
>portable ones. From some reports that I got the fixed stoves do prove less
>efficient (I guess around 30% saving), but I don't really have the critical
>mass of figures supporting that. As it is not the main focus of the
>promotion, there has also been no assessment done. Bear in mind, we are a
>food security programme and the stove promotion is only one part in our
food
>processing sector, which is one of 7 sectors of our project. I don't claim
>to be a stove expert (yet). As I myself am not 100% convinced on the fixed
>stoves, I am bit wary of pushing them. I found them introduced when I took
>over the project here.
>Of course in the picture page where the fixed stove is shown, I did not
>mention anything about the way how to construct it and that you should
build
>a layer of insulation in there. That is not a 'how-to-guide' yet and I am
>also not so sure, if we should do one on that type, as we are more
conivnced
>about the portable stove.
>Grant, what do you think? I definitely support the idea on adding a comment
>on that page, that this model shouldn't be the favourite and most promoted
>one. But I would never prevent people from constructing one, after it all,
I
>see our role to give them choices. And some people do have reasons to opt
>for those. They are definitely not the ideal solution, but still better
than
>the 3 stone-stone, as far as our users observe, otherwise they wouldn't go
>for them.
>Grant, could you add a comment to the picture page wher the fixed stove is
>appearing that you think is suitable?
>Dean, What type of insulation do you use in your fixed stoves? I would be
>interested to know more about 'your' stove and very much support the idea
of
>having a 'how-to-guide' available, even on the same website or at least
with
>a link there.
>
>I hope that leads something good.
>Sorry, some other work is waiting as I am still stuck with most of the
>administrative tasks of running our project.
>Looking forward to your comments.
>Christa
>
>PS I just found TOms mail with the website-indication for the AProvecho
>stoves etc. I'll have to wait until the weekend for internet access, so
>can't comment on that now. That makes one of the questions above obsolete.
>
>
>
>
>
>
>
>
>----- Original Message -----
>From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
>To: "Dean Still" <dstill@epud.net>; <STOVES@LISTSERV.REPP.ORG>;
><hedon@yahoogroups.com>
>Cc: "Christa Roth" <messinger.roth@Africa-Online.net>
>Sent: Wednesday, February 05, 2003 9:18 PM
>Subject: Re[2]: Different Types of Energy Saving Stoves In Southern Malawi
>
>
>> Hello Dean,
>>
>> I agree completely with your criticisms of the heavy mass stoves shown
>> in the pictures at www.ecoharmony.net/hedon/malawistoves.php - fuel
>> inefficient and smokey.
>>
>> The clay stove (www.ecoharmony.net/hedon/claystove.php) is, I believe,
>> fuel saving although probably not 'lower smoke emitting' - it is a
>> modification of the ITDG design used in Kenya, which has been
>> carefully tested/monitored over the years. After significant emissions
>> & efficiency testing I did some years ago (www.ecoharmony.com/thesis)
>> I too was skeptical about fuel savings from the clay stoves being
>> disseminated, but have since been shown convincing evidence from ITDG
>> & GTZ. On the emissions front, though, ITDG's recent Indoor Air
>> Quality testing of these devices in use have not shown significant
>> emission reductions - or so I have heard.
>>
>> Your point is still valid - it would certainly be much better to work
>> on and promote insulated, low-mass combustion chambers as you are
>> doing at Aprovecho! Would you be able to draft a similar 'how-to
>> guide' (similar style) on how to make the Rocket Stove. I know you
>> have some information at www.efn.org/~apro/attitlepage.html, but I
>> don't see any step-by-step guidelines which development organisations
>> could follow. Would you be willing to help make one?
>>
>> I will introduce some additional explanation on the existing online
>> how-to guides (Christa - could you help?) so as not to confuse/mislead
>> readers.
>>
>> Thanks for the contribution
>>
>> Grant
>>
>> Wednesday, February 5, 2003, 2:17:07 PM, you wrote:
>>
>> DS> Dear Stovers,
>>
>> DS> The clay/sand stoves shown by Christa Roth and Christoph Messinger
>are,
>> DS> unfortunately, good examples of stoves that have in laboratory tests
>been
>> DS> shown to use more firewood than three stone fires. Just surrounding
>the fire
>> DS> with heavy earthen materials does not raise combustion temperatures.
>The
>> DS> mass actually lowers combustion temperatures for hours until the
stove
>body
>> DS> has come up to temperature itself. The heat is diverted from its
>intended
>> DS> purpose: to cook food. Why heat up hundreds of pounds of stove body
>when
>> DS> cooking five - ten pounds of food?
>>
>
>
>
>

----------
Does your organisation feature on the Shell Foundation online database? Take a look at http://ecoharmony.net/hedon/org.php to find out more.

Please feel free to forward this mail to any of your colleagues or business partners. We rely on users to spread the word about HEDON to the entire Household Energy community. In addition, please consider adding your own material to the HEDON web page resources. This is a simple process and can go a long way towards generating publicity for your activites among a select audience of professionals.

For more information about HEDON visit:
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From kchisholm at CA.INTER.NET Sun Feb 9 19:31:13 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod
#6
Message-ID: <SUN.9.FEB.2003.203113.0400.KCHISHOLM@CA.INTER.NET>

Dear Lanny

> Dear Tom,
> I only have a co tester but I usually just go by the clearness of the
> exhaust.

Stack clearness is a pretty good indiction of completeness of wood
combustion.

> When testing emissions we should test the concentration of the combustion
> products in the exhaust and the volume of the exhaust, right?
> If so how do you measure the volume of the exhaust without interfering
with
> the flow?

All other things being equal, a very simple way is to simply measure the
%CO2 in the stack gases. It would be in the range of 12-13% for perfect
combustion, with no excess air.... anything less is caused by dilution with
excess air. So, you don't really need to measure teh incoming air.... just
measure the results.

However, if you want to measure the rate of air consumption in a crude and
simple way, get a piece of "dry cleaner plastic", as used for protecting
cleaned garments. It is 1-2 mil thickness polyethylene.... much thinner
than garbage bags. Inflate the bag, and note how long it takes to deflate
when connected to teh stove intake..

Kindest regards,

Kevin

From crispin at NEWDAWN.SZ Mon Feb 10 02:17:15 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:13 2004
Subject: Different Types of Energy Saving Stoves In Southern Malawi
Message-ID: <MON.10.FEB.2003.091715.0200.CRISPIN@NEWDAWN.SZ>

Dear Tom

>I visited the site below and thought it was the best summary of responsible
stove testing I have seen.

Hang on... which site was the one you mean? I got lost in all that otehr
stuff.

Regards
Crispin

From mheat at MHA-NET.ORG Mon Feb 10 08:39:55 2003
From: mheat at MHA-NET.ORG (Norbert Senf)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod
#6
In-Reply-To: <00ee01c2d09b$ec6efc40$b29a0a40@kevin>
Message-ID: <MON.10.FEB.2003.083955.0500.MHEAT@MHANET.ORG>

At 08:31 PM 2003-02-09 -0400, Kevin Chisholm wrote:
>(snip)
>However, if you want to measure the rate of air consumption in a crude and
>simple way, get a piece of "dry cleaner plastic", as used for protecting
>cleaned garments. It is 1-2 mil thickness polyethylene.... much thinner
>than garbage bags. Inflate the bag, and note how long it takes to deflate
>when connected to teh stove intake..

Canada Mortgage and Housing (CMHC) Research Division has developed a
similar method for measuring the output of heating ducts. They use a
standard brand green plastic garbage bag available in North America. The
inflated volume of the bag is known, so this simplifies the measurement.
Otherwise, you'd have to measure the volume of the bag first, unless you
are doing comparative measurements only.

Norbert

From tombreed at ATTBI.COM Mon Feb 10 01:16:56 2003
From: tombreed at ATTBI.COM (Tom Reed)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod
#6
Message-ID: <SUN.9.FEB.2003.231656.0700.TOMBREED@ATTBI.COM>

Dear Tom Miles and all:

I am currently reworking my lab to make it safer, fireproof and more
accurate. I have just purchased a 5 gas VETRONIX portable gas meter for the
National Alternative Fuels Foundation (NAFF) and will be using it mostly on
fuel testing. (Cost $8,000).

I will be installing a kitchen hood over my fuel mixing/stove testing area.
I'll probably mount my digital Nighthawk CO meter in the 100 cfm exhaust
stream. I can also put the 5 gas meter probe there. This will even out the
wild excursions of measuring directly over pot, and more closely simulate
room air and breathing air.

Any further suggestions? Drywalling this week.

TOM REED BEF STOVEWORKS

Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
----- Original Message -----
From: "Tom Miles" <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, February 09, 2003 5:08 PM
Subject: Re: [STOVES] Emission testing question /Re: [STOVES] Simple Camp
Stove Mod #6

> Lanny,
>
> I would ignore the volume measurements and let a lab that is set up to
> capture volume do that. If you were in a laboratory in Germany testing
> Crispin's Shisa stove you would probably use the procedures in DIN 18891.
> Norbert Senf and the Masonry Heater Association folks are most familiar
with
> the different methods for testing. (See Edvark Karlsvik's comparison of
the
> different laboratory methods on the MHA site at:
> http://mha-net.org/docs/karlsvik.PDF )
>
> For development and tuning purposes you are really most interested in the
> effect of your air and fuel adjustments on temperature at the work (pot or
> plancha) and CO and O2 emissions in the stack. Find the combination of
> firing rate (wood feed), and air adjustment (overfire, underfire) that
gives
> you the lowest average CO under different load (boiling water, etc)
> conditions. You'll find that CO will jump all over the map but after a
while
> you'll get a feel for it. Check the gas conditions around the pot and in
the
> stack. It would be interesting to see what CO you get after the stove has
> heated up and when you're burning mostly char.
>
> I'm hoping that discussion on the list will lead to some commonly adopted
> methods for cook stoves testing for combustion efficiency, heating
> efficiency, cooking efficiency and emissions.
>
> Tom
>
>
> ----- Original Message -----
> From: "Lanny Henson" <lanny@ROMAN.NET>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Sunday, February 09, 2003 6:00 PM
> Subject: [STOVES] Emission testing question /Re: [STOVES] Simple Camp
Stove
> Mod #6
>
>
> > Dear Tom,
> > I only have a co tester but I usually just go by the clearness of the
> > exhaust.
> > When testing emissions we should test the concentration of the
combustion
> > products in the exhaust and the volume of the exhaust, right?
> > If so how do you measure the volume of the exhaust without interfering
> with
> > the flow?
> > Lanny
>

From kchisholm at CA.INTER.NET Mon Feb 10 08:53:24 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod
#6
Message-ID: <MON.10.FEB.2003.095324.0400.KCHISHOLM@CA.INTER.NET>

Dear Norbert

You can measure the volume of the bag by filling it with the lightweight
"plastic popcorn" used for packing materials for shipment.

It causes the bag to fill to the inflated shape, without stretching it
significantly.

Kindest regards,

Kevin
----- Original Message -----
From: "Norbert Senf" <mheat@MHA-NET.ORG>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, February 10, 2003 9:39 AM
Subject: Re: [STOVES] Emission testing question /Re: [STOVES] Simple Camp
Stove Mod #6

> At 08:31 PM 2003-02-09 -0400, Kevin Chisholm wrote:
> >(snip)
> >However, if you want to measure the rate of air consumption in a crude
and
> >simple way, get a piece of "dry cleaner plastic", as used for protecting
> >cleaned garments. It is 1-2 mil thickness polyethylene.... much thinner
> >than garbage bags. Inflate the bag, and note how long it takes to deflate
> >when connected to teh stove intake..
>
> Canada Mortgage and Housing (CMHC) Research Division has developed a
> similar method for measuring the output of heating ducts. They use a
> standard brand green plastic garbage bag available in North America. The
> inflated volume of the bag is known, so this simplifies the measurement.
> Otherwise, you'd have to measure the volume of the bag first, unless you
> are doing comparative measurements only.
>
> Norbert

From tmiles at TRMILES.COM Mon Feb 10 12:17:16 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:13 2004
Subject: Fw: [hedon] Different Types of Energy Saving Stoves In Southern
Malawi
Message-ID: <MON.10.FEB.2003.091716.0800.TMILES@TRMILES.COM>

----- Original Message -----
From: GTZ-Zimbabwe Mushamba ZW
To: hedon@yahoogroups.com
Sent: Monday, February 10, 2003 5:38 AM

Subject: [hedon] Different Types of Energy Saving Stoves In Southern Malawi

Dear All
To all who have contributed and shown interest in the above subject, here is a contribution from ProBEC. I hope this goes through now Grant.

The "How-to guide" authored by Christa Roth on clay stoves in Southern Malawi has generated a lot of interesting discussion and useful contributions by researchers and practitioners from different parts of the world. For the past 3 years GTZ, through ProBEC (Programme for Biomass Energy Conservation in Southern Africa) has been supporting interventions to improve the energy supply and utilization patterns for households and small-scale enterprises in the SADC region. This programme has yielded some useful experiences and lessons which I would like to share with you all.

1. Firstly I would like to thank Christa and Christoph for sparking this healthy debate. It affords us all an opportunity to exchange our diverse experiences, which should hopefully enhance our own understanding of the issues at play and success factors for improved biomass stoves, which in turn should lead to the improvement of the quality of life for the millions of people dependent on biomass energy for their livelihoods today.

From 10-14 March 2003, ProBEC is hosting a workshop at the Vaal Triangle Technikon just outside Johannesburg in South Africa, which brings together stove designers and implementers of improved stove projects to provide a forum for further debate and seek agreement on minimum quality standards for improved biomass stoves.

2. Dean Still is correct when he condemns high mass UNISULATED clay/mud stoves for being inefficient. I know of programmes that have promoted such stoves erroneously believing that they were efficient, only to be confronted with disastrous results. Many of us have learnt from such bad experiences, and we should continue to learn with an open mind.
3. In the BEC interventions or projects which are going on with the support of ProBEC in the different countries in Southern Africa, the clay and/or mud stove has so far taken off ahead of many others. This is measured in terms of numbers disseminated and frequency of use by the owners. In particular, households in certain districts in Malawi and Zimbabwe have accepted and adopted the clay stove quite readily.
4. ProBEC is promoting two types of mud/clay stove, that is the portable and the inbuilt stove. The former is adequately described in Christa's guide, although there are slight variations from one region/country to another mainly necessitated by the need to cater for different shapes and/or sizes of cooking pots. The in-built mud stove is insulated from the floor and kitchen walls using wood ash. Efficiency is achieved because the pot is sitting directly above and "seeing" the fire. (This is the sort of language used when training the stove builders). The pot-fire distance is also optimized to ensure maximum heat transfer, and stove builders use the figure of 18 to 20 cm as a rule of thumb. Clearance between the rim of the stove and the edge of the pot sitting in the stove equals or is less than the breath of your small finger. If a multiple-pot stove is required, it is recommended to build one with separate fire boxes for each pot in order to maintain this direct path of heat from the fire to the pot. All the above stove design features are good for not only radiative and convectional heat, but for conduction from the flue gases to the pot as well.
5. Fuelwood consumption tests done on the mud stove in one district in 2001 indicated Fuelwood savings ranging from 30-50%. Stephen Gitonga observes that fuel efficiency seems to be the only common ground between stove builders and users. Given realities encountered in the field which include low literacy levels, inavailability of equipment, time pressure and so on, rigorous scientific testing is often not feasible. We are interested to get you views as to how far the testing process can be simplified before compromising validity.
6. We are interested to learn about other low-cost insulating materials, better than wood ash. Vermiculite is available cheaply in South Africa but not in the other countries in the region. Dean mentions a list of insulators but I am not sure how cheap these are.
7. Smoke removal and reduction of harmful emissions from the kitchen are important considerations for improved biomass stoves. This is especially so considering the crucial role of a clean kitchen environment in the home-based care of HIV/AIDs patients. (The pandemic has an alarming prevalence in the region). In both Malawi and Zimbabwe, siting and positioning of the fixed mud stoves in the kitchen are done with due consideration to the prevalent wind direction for a given locality. The stove is therefore built below a small window or other aperture on the windward side of the kitchen. If a suitable opening is not in place, the stove builder has to persuade the house owner to create one. It is easier though where a new kitchen is under construction, which is the case in many parts of Zimbabwe due to the land redistribution and resettlement programme. When the stove is in operation, the emitted smoke tends to flow up the kitchen wall and out through the opening at the top of the kitchen wall. I have some photos showing the effectiveness of this method of smoke removal, but I have to reduce the pixel size first before I can mail them. If you are interested, just give me a shout.
8. Among other things combustion efficiency, and therefore emission reduction is very much a function of the moisture content of the wood used in the stove. The clay stoves being disseminated in Zimbabwe incorporate an adjoining cubicle for storage of split wood, to dry it further before eventual use in the stove. End-user practices such as proper handling of the fuel-wood and improved cooking practices are critical for the ultimate achievement of efficiency by the stove.
9. I mentioned earlier the popularity of clay/mud stoves as opposed to others such as metal ones. As a guiding principle, ProBEC does not favour one type of improved stove as opposed to another. The main consideration is that the stove should meet basic performance and operational criteria. By and large, the job of stove selection is left to the users. It would appear that clay stoves are favoured mainly because, being made of a freely occurring natural resource, they are low cost and yet they still give the advantages of a cleaner kitchen environment, consume less wood and are able to utilize heat from residual ambers. The issue of low cost cannot be overemphasized, considering that of the 2 billion people reported to be living on less than US$1/day, a substantial number is living in Africa.
10. I would not deny that a well managed open fire (3-stone fireplace) can achieve a PHU value as high as 20%. But only firewood which is above a certain critical size can be used successfully to cook on an open fire. The fire from twigs, crop stalks, maize cobs, etc. is very quickly blown away and spent before one can prepare a meal on it. Stephen Gitonga makes a similar observation in hiscontribution With the clay stove, it is possible to use twigs and some crop residues to prepare a meal to the standard which adequately meets the expectations of the users.
11. Among the stoves in our shortlist are the portable metal stove from Mali, the Turbo stove developed by Tapio Niemi of Finland, the Mulanje stove being promoted in southern Malawi, the Mud stove being used in northern Malawi and Zimbabwe, the Rocket and Eco stoves developed by Approvecho, the Shisa stove by Dawn Engineering of Swaziland and the Namibian tsotso stove. We see these as promising prototypes although some require considerable work to improve them, and as pointed out earlier, it is the users who should be the final judges.
12. In June/July 2002, the Rocket stove from Approvecho was demonstrated to households in rural villages of South Africa. They were all impressed (and so was I) with the low smoke emission from the stove and the quick cooking. However, there were a number of sticking points: one had to feed the stove with wood every few minutes, which increases the time required for tending the fire compared to other stoves; the vermiculite at the top was exposed and mothers were concerned children would temper with it; the skirt for directing hot gases to scrape the sides of the pot posed a risk of cutting the user; handles to lift the stove were missing. For me the rocket stove is very promising but these concerns from the potential end-users need to be addressed first.
13. As mentioned earlier, ProBEC is hosting a workshop on "Stove design and marketing strategies" where the developers and promoters of the improved stoves above are invited to present the technical details and operation of their products. This will be followed by a review, critique and recommendations for improvements by the other workshop participants. The major output expected from the workshop is a set of quality and performance criteria to serve as a minimum standard for biomass stoves. I would very much like to hear your views and comments about the workshop concept.

Best regrds

Paul J. M. Mushamba

----------
Does your organisation feature on the Shell Foundation online database? Take a look at http://ecoharmony.net/hedon/org.php to find out more.

Please feel free to forward this mail to any of your colleagues or business partners. We rely on users to spread the word about HEDON to the entire Household Energy community. In addition, please consider adding your own material to the HEDON web page resources. This is a simple process and can go a long way towards generating publicity for your activites among a select audience of professionals.

For more information about HEDON visit:
http://ecoharmony.net/hedon

NOTE: Advertisements in this message have been added by Yahoo Groups who provides us with free email group services. HEDON does not endorse products or support the advertisements in any way.

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

From psanders at ILSTU.EDU Mon Feb 10 23:56:16 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:13 2004
Subject: ] Fw: charcoal from bamboo and activated carbon
In-Reply-To: <20030206063308.LDYJ4529.mta02-svc.ntlworld.com@[62.253.52. 64]>
Message-ID: <MON.10.FEB.2003.225616.0600.PSANDERS@ILSTU.EDU>

Stovers,

I am forwarding this message from Thomas.

I think he did not use the new address for the Stoves List:

STOVES@LISTSERV.REPP.ORG

( We are not to use the old ....@crest.org address.)

Paul

>>>Date: Wed, 05 Feb 2003 07:29:32 +0000
>>>From: Thomas Stubbing <"Thomas Stubbing <thomas.stubbing"@heat-win.co.uk>>
>>>Subject: Re: [STOVES] Fw: charcoal from bamboo and activated carbon
>>>
>>>Dear Stovers,
>>>
>>>When Mr Agarwal's enquiry first appeared I wrote to him as follows but
>>>as yet have not had a reply:
>>>Please let me know what hourly weight of bamboo you have available to
>>>carbonise in a preferably 24 hours/day, environmentally friendly process
>>>enabling the
>>>pyrolysis gases produced to heat the machine with a large energy surplus
>>>available to generate electricity.
>>>
>>>If the weight available is sufficient to justify the capital cost of a
>>>continuous processor we can probably offer you a profitable solution.
>>>
>>>
>>>Paul is right in thinking that activation is a follow-on process as it
>>>takes place at around 800 oC, when virtually all organic volatiles are
>>>removed, and I believe involves subsequent cleaning of the materials
>>>pores with dilute sulphuric acid vapour.
>>>
>>>Mr Agarwal now mentions a " Bamboo Charcoal and Vinegar plant."
>>>
>>>To obtain vinegar efficiently I think he needs first to dry the bamboo,
>>>preferably in a superheated steam atmosphere to avoid ignition in the
>>>dryer, at up to around 200 oC and then torrefy the dry material in the
>>>absence of air at around 270 oC while condensing the substantially
>>>acetic acid vapour which comes off it as the lignocellulose breaks
>>>down. The material is then easily grindable if requred for co-firing
>>>with powdered coal by an electricity generator and is then in any event
>>>a good, virtually smokeless fuel.
>>>
>>>The torrefied bamboo can then be carbonised in the absence of air and
>>>the pyrolysis gases generated used as a gaseous fuel.
>>>
>>>I hope this helps.
>>>
>>>Regards,
>>>
>>>Thomas

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From tmiles at TRMILES.COM Tue Feb 11 13:27:55 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:13 2004
Subject: Fw: [hedon] Re: response to Paul J. M. Mushamba
Message-ID: <TUE.11.FEB.2003.102755.0800.TMILES@TRMILES.COM>

>From: Dean Still
>To: GTZ-Zimbabwe Mushamba ZW ; ethos ; hedon@yahoogroups.com
>Sent: Monday, February 10, 2003 1:46 PM

Dear Stovers,

It was a sobering experience for Aprovecho stove designers when they were
confronted with proof from university researchers that their beloved stove,
the Lorena, was not really "fuel efficient" although books published by
Aprovecho claimed the savings were 50%. Over the last 20 years the
understanding of how stoves work has grown to the point where there are
substantive grounds of common understanding. Both how to clean up combustion
and how to increase heat transfer to the pot are now generally accepted
engineering concepts.

Dr. Larry Winiarski has come up with a set of design principles that can be
used in many different stoves. Larry likes to start out discussions of stove
design by saying that there is no such thing as a Rocket stove! Stoves that
use the Rocket design principles are always different depending on use and
materials available. A mud stove and a two pot stainless steel stove with
chimney can both be Rocket stoves. Larry's design principles follow this
letter.

I believe that the fastest and most successful way to design a stove that
will be widely appreciated and used is to involve local women in the design
committee. When HELPS International was designing it's very successful
griddle stove in Guatemala ten local women were responsible for adapting the
stove to their needs. The stove went through several important revisions
before the whole committee loved the stove and was sure that it would be
loved by other women. This process took about a year but I think that it
makes sense to follow this pattern. Large companies always do product
testing before introducing new products. Without product testing we can not
know for sure whether some important variable has been overlooked,
forgotten.

Insulating mud stoves is a good idea. The insulated combustion chamber can
be coated with mud so that the appearance of the stove is the same. But the
insulating combustion chamber helps to reduce smoke, makes the stove much
easier to light, faster to boil, and assists burning green wood. We have
developed the following methods for making indigenous insulative combustion
chambers:

1.) 50% clay added to 50% sawdust or other burnable material
2.) 15% clay added to 85% perlite
3.) 15% clay added to 85% pumice
4.) 25% clay added to 75% vermiculite
5.) Using locally made floor tiles
6.) We are experimenting with charcoal/clay presently.

These tiles or bricks or molded shapes are fired in a kiln. Floor tiles,
usually red clay and porous in nature, have been used in Central America
for 4 years without breaking in the combustion chambers of Rocket type
stoves. The floor tile is surrounded by any lightweight insulation . In
Guatemala these tiles are called "baldosa" and are inexpensive. I'm told
that they are made also in Rwanda.

Without testing we would not have been convinced that the Lorena was not
fuel efficient. The boiling test, using the same pot every time, is largely
accepted as showing differences between stoves. Make bundles of wood that
are the same weight, say a couple of pounds. Using the same pot 3/4 full of
water, say 10 pounds of water, burn the wood in the stove allowing 8600BTU
per pound of wood and 1005BTU for a pound of water boiled away. The sensible
heat (rise in water temperature) added to the latent heat (calculated by
weighing remaining water) is the amount of energy gotten into the pot. 2
times 8600BTU's or 17,200BTU's is the total energy expended. Some folks give
a credit for charcoal remaining in the stove. But even a simple test like
this will give designers an idea of fuel efficiency. Each test should be
done a minimum of three times by a cook not involved with the project.
(Expert stove testers can make their own stove perform remakably well
without intending to effect the results. Inventors pride is a constant
problem here at Aprovecho!)

The spirit of collaboration that is so evident in these conversations shows
the open minded committment of GTZ, ProBec and others to help those using
stoves. It is a great pleasure to work in this atmosphere and it makes me
confident that safer, cleaner and more efficient stoves are on their way to
those in need.

Rocket Stove Principles

Dr. Larry Winiarski
Technical Director
Aprovecho Research Center
Apro@efn.org

1.) Insulate particularly the combustion chamber with low mass, heat
resistant materials in order to keep the fire as hot as possible and not to
heat the higher mass of the stove body.

2.) Within the stove body, above the combustion chamber, use an insulated,
upright chimney of a height that is about two or three times the diameter
before extracting heat to any surface (griddle, pots, etc.).

3.) Heat only the fuel that is burning (and not too much). Burn the tips of
sticks as they enter the combustion chamber, for example. The object is NOT
to produce more gasses or charcoal than can be cleanly burned at the power
level desired.

4.) Maintain a good air velocity through the fuel. The primary Rocket stove
principle and feature is using a hot, insulated, vertical chimney within the
stove body that increases draft.

5.) Do not allow too much or too little air to enter the combustion chamber.
We strive to have stoichiometric (chemically ideal) combustion: in practice
there should be the minimum excess of air supporting clean burning.

6.) The cross sectional area (perpendicular to the flow) of the combustion
chamber should be sized within the range of power level of the stove.
Experience has shown that roughly twenty-five square inches will suffice for
home use (four inches in diameter or five inches square). Commercial size is
larger and depends on usage.

7.) Elevate the fuel and distribute airflow around the fuel surfaces. When
burning sticks of wood, it is best to have several sticks close together,
not touching, leaving air spaces between them. Particle fuels should be
arranged on a grate.

8.) Arrange the fuel so that air largely flows through the glowing coals.
Too much air passing above the coals cools the flames and condenses oil
vapors.

9.) Throughout the stove, any place where hot gases flow, insulate from the
higher mass of the stove body, only exposing pots, etc. to direct heat.

10.) Transfer the heat efficiently by making the gaps as narrow as possible
between the insulation covering the stove body and surfaces to be heated but
do this without choking the fire. Estimate the size of the gap by keeping
the cross sectional area of the flow of hot flue gases constant. EXCEPTION:
When using a external chimney or fan the gaps can be substantially reduced
as long as adequate space has been left at the top of the internal short
chimney for the gasses to turn smoothly and distribute evenly. This is
tapering of the manifold. In a common domestic griddle stove with external
chimney, the gap under the griddle can be reduced to about one half inch for
optimum heat transfer.

All Best,

Dean Still
Director
Advanced Studies in Appropriate Technology
Aprovecho Research Center

From Carefreeland at AOL.COM Tue Feb 11 17:31:46 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:13 2004
Subject: (or fuels ?): Different Types of Energy Saving Stoves In
Souther...
Message-ID: <TUE.11.FEB.2003.173146.EST.>

In a message dated 2/6/03 2:20:34 AM Eastern Standard Time,
kchisholm@ca.inter.net writes:

> > Daniel's comments/ questions
>
> Dear Richard
>
> It depends on the plastic employed to manufacture the bag...
>
> If it was polyethylene, with inert fillers, and non-toxic inks, then there
> should be no environmental problem.

> Kevin, I burn a lot of discarded empty polyethylene de-icing salt bags
to rapidly raise the temperature of my greenhouse woodstove. The only
significant pigment is a yellow powder which somewhat survives the combustion
process and shows up in the ash. Do you or anyone know what this pigment is,
and if it would make my wood ash toxic as a fertilizer?
Daniel Dimiduk

However, if it was a poly vinyl chloride
>
> (PVC) based plastic, there is potential for significant problems. On
> combustion, the chlorine is released, and there is a potential to create
> dioxanes and possibly other nasty compounds.
>
> From a briquetting standpoint, "too much" plastic that was "too big" might
> create bonding problems, and weakness of the briquette.
>
> Kindest regards,
>
> Kevin
>

From kchisholm at CA.INTER.NET Tue Feb 11 18:07:21 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:13 2004
Subject: (or fuels ?): Different Types of Energy Saving Stoves In
Souther...
Message-ID: <TUE.11.FEB.2003.190721.0400.KCHISHOLM@CA.INTER.NET>

Dear Dan

> Kevin, I burn a lot of discarded empty polyethylene de-icing salt bags to rapidly raise the temperature of my greenhouse woodstove. The only significant pigment is a yellow powder which somewhat survives the combustion process and shows up in the ash. Do you or anyone know what this pigment is, and if it would make my wood ash toxic as a fertilizer?
Daniel Dimiduk
I am guessing here, but I feel that if you have salt present, you have potentially nasty conditions. The carbon/hydrogen in the polyethylene would act as a reducing agent when ignited. Chances are that you would reduce the NaCl to Na and Cl, but that the Na would immediately oxidize to Na2O and go off as a fume. The Chlorine component would likely go up the stack as a "complex chlorine compound."

I am guessing that the yellowish ash that remains is primarily pigment as you indicate; most residual salt would be fumed off. The simplest thing would be to phone the packager of the salt and ask where he gets his bags. Then ask the bag supplier who does the printing. Then ask the printer who supplies the ink, and then ask the ink man what the yellow residue is. This is tedious, but low cost. Alternatively, you may be able to get a Textbook on "Qualitative Analysis, and figure what to do. Or, give it to a Chemistry Teacher, and ask them what it is.

Hope this is not overly complicated.

Kindest regards,

Kevin

From Carefreeland at AOL.COM Tue Feb 11 18:41:27 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question /Re: [STOVES] Simple Camp Stove Mod
#6
Message-ID: <TUE.11.FEB.2003.184127.EST.>

In a message dated 2/10/03 8:55:40 AM Eastern Standard Time,
tombreed@attbi.com writes:

> Dan's comments
>
>
> Dear Tom Miles and all:
>
> I am currently reworking my lab to make it safer, fireproof and more
> accurate. I have just purchased a 5 gas VETRONIX portable gas meter for
> the
> National Alternative Fuels Foundation (NAFF) and will be using it mostly on
> fuel testing. (Cost $8,000).
>
> I will be installing a kitchen hood over my fuel mixing/stove testing area.
> I'll probably mount my digital Nighthawk CO meter in the 100 cfm exhaust
> stream. I can also put the 5 gas meter probe there. This will even out
> the
> wild excursions of measuring directly over pot, and more closely simulate
> room air and breathing air.
>
> Any further suggestions? Drywalling this week.
>
> TOM REED BEF STOVEWORKS
>
> > Hi Tom, It's good for us both to be back up and running.
> Can you set up the metering hood to have a "chimney duct" to capture only
exhaust gas from the stove being tested? To keep from establishing a serious
negative pressure at the stove outlet, you could have a vacuum by-pass outlet
on this duct. This would keep the vacuum of the exhaust hood from
interfering with the normal flow through the stove. Then either measure the
airflow through the exhaust duct, or the by-pass. The airflow through the
by-pass would be calculated with the results giving an air dilution rate.
> I understand that in normal operation the hood would simulate indoor air
quality, but isn't the stove exhaust output really what we usually want? A
damper on the by-pass could control the airflow to balance.
> Just some thoughts.
Your stover friend,
Dan Dimiduk

From lanny at ROMAN.NET Wed Feb 12 09:29:07 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:13 2004
Subject: Tom Reed's Hood
Message-ID: <WED.12.FEB.2003.062907.0800.LANNY@ROMAN.NET>

Hey Tom,
Just a few comments about exhaust hoods.
1- As a rule of thumb I use 100 cfms per sq ft of hood area for commercial
applications. But you are not generating as much fumes as commercial kitchen
equipment. If your 100 cfm fan is insufficient see #2 and #3.
2- A/C supply vents, fans, and any other turbulences will kick fumes out
from under the hood before it has a chance to capture them.
It is good to use A/C grills with adjustable louvers so you can divert the
flow away from the hood and it is best to install grills far away from the
hood.
3- Enclosures improve a hoods performances. It is good to mount the hood on
a wall, that encloses one side, then add a side panel or two to box it in if
necessary. Increasing the height (top to bottom) of the hood also helps.
A 100 cfm fan may exhaust a small stove because the heat rises toward the
fan. But I drought that it will capture dust from fuel mixing you will need
50 to 100 fpm velocity across your surface area for that.
You could box it in like a lab hood. I could send you a rolling track
assembly for front sliding glass doors if necessary.

Good Luck, Lanny

----- Original Message -----
From: Tom Reed <tombreed@attbi.com>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, February 09, 2003 10:16 PM
Subject: Re: [STOVES] Emission testing question /Re: [STOVES] Simple Camp
Stove Mod #6

> Dear Tom Miles and all:
>
> I am currently reworking my lab to make it safer, fireproof and more
> accurate. I have just purchased a 5 gas VETRONIX portable gas meter for
the
> National Alternative Fuels Foundation (NAFF) and will be using it mostly
on
> fuel testing. (Cost $8,000).
>
> I will be installing a kitchen hood over my fuel mixing/stove testing
area.
> I'll probably mount my digital Nighthawk CO meter in the 100 cfm exhaust
> stream. I can also put the 5 gas meter probe there. This will even out
the
> wild excursions of measuring directly over pot, and more closely simulate
> room air and breathing air.
>
> Any further suggestions? Drywalling this week.
>
> TOM REED BEF STOVEWORKS
>
> Dr. Thomas B. Reed
> 1810 Smith Rd., Golden, CO 80401
> tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
> ----- Original Message -----
> From: "Tom Miles" <tmiles@TRMILES.COM>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Sunday, February 09, 2003 5:08 PM
> Subject: Re: [STOVES] Emission testing question /Re: [STOVES] Simple Camp
> Stove Mod #6
>
>
> > Lanny,
> >
> > I would ignore the volume measurements and let a lab that is set up to
> > capture volume do that. If you were in a laboratory in Germany testing
> > Crispin's Shisa stove you would probably use the procedures in DIN
18891.
> > Norbert Senf and the Masonry Heater Association folks are most familiar
> with
> > the different methods for testing. (See Edvark Karlsvik's comparison of
> the
> > different laboratory methods on the MHA site at:
> > http://mha-net.org/docs/karlsvik.PDF )
> >
> > For development and tuning purposes you are really most interested in
the
> > effect of your air and fuel adjustments on temperature at the work (pot
or
> > plancha) and CO and O2 emissions in the stack. Find the combination of
> > firing rate (wood feed), and air adjustment (overfire, underfire) that
> gives
> > you the lowest average CO under different load (boiling water, etc)
> > conditions. You'll find that CO will jump all over the map but after a
> while
> > you'll get a feel for it. Check the gas conditions around the pot and in
> the
> > stack. It would be interesting to see what CO you get after the stove
has
> > heated up and when you're burning mostly char.
> >
> > I'm hoping that discussion on the list will lead to some commonly
adopted
> > methods for cook stoves testing for combustion efficiency, heating
> > efficiency, cooking efficiency and emissions.
> >
> > Tom
> >
> >
> > ----- Original Message -----
> > From: "Lanny Henson" <lanny@ROMAN.NET>
> > To: <STOVES@LISTSERV.REPP.ORG>
> > Sent: Sunday, February 09, 2003 6:00 PM
> > Subject: [STOVES] Emission testing question /Re: [STOVES] Simple Camp
> Stove
> > Mod #6
> >
> >
> > > Dear Tom,
> > > I only have a co tester but I usually just go by the clearness of the
> > > exhaust.
> > > When testing emissions we should test the concentration of the
> combustion
> > > products in the exhaust and the volume of the exhaust, right?
> > > If so how do you measure the volume of the exhaust without interfering
> > with
> > > the flow?
> > > Lanny
> >
>

From yark at U.WASHINGTON.EDU Wed Feb 12 10:47:46 2003
From: yark at U.WASHINGTON.EDU (Tami Bond)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing question
In-Reply-To: <6e.2a4832fd.2b7ae427@aol.com>
Message-ID: <WED.12.FEB.2003.074746.0800.YARK@U.WASHINGTON.EDU>

Yeah Tom!!

Grant Ballard-Tremeer did some work on looking at whether hoods affect
combustion.

You could find his paper:
Ballard-Tremeer, G., and H.H. Jawurek, The "hood method" of measuring
emissions of rural cooking devices, Biomass and Bioenergy, 16 (5),
341-345, 1999.

But I think 100 cfm is okay, although you didn't say how big your hood was
(kitchen range size?) Put a damper in before you install the duct and then
you can always turn the flow down if need be.

There's some distance between hood and combustor that should minimize
spillage. I think it is ~45 cm. I always had problems with spillage
anyway, but instead of enclosing with hard sides I used some very light
plastic, hoping that this would allow some pressure equalization.

Tell us about your gas meter: gases, precision?

Dan said:
> > Can you set up the metering hood to have a "chimney duct" to capture only
> exhaust gas from the stove being tested?

I'm not sure what this means; are you proposing capturing the stove
exhaust and only that? Probably not. But anyway, the hood simulates not
only indoor AQ, but also what really happens to the exhaust after it
leaves the stove-- unless, of course, it has a chimney already.

Tami

From lanny at ROMAN.NET Wed Feb 12 13:28:06 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:13 2004
Subject: Lanny's day off/ [hedon] Re: response to Paul J. M. Mushamba
Message-ID: <WED.12.FEB.2003.102806.0800.LANNY@ROMAN.NET>

Dear stove friends,
This is my day off, just for Stoves and barbecue and beer so I may be
blathering up the list. Hopefully my keyboard breathalyzer will protect you
:-)
See my 4 comments below.

----- Original Message -----
> From: Tom Miles <tmiles@TRMILES.COM>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Tuesday, February 11, 2003 10:27 AM
> Subject: [STOVES] Fw: [hedon] Re: response to Paul J. M. Mushamba
>
>
> >From: Dean Still
> >To: GTZ-Zimbabwe Mushamba ZW ; ethos ; hedon@yahoogroups.com
> >Sent: Monday, February 10, 2003 1:46 PM
>
>
> Dear Stovers,
>
> >It was a sobering experience for Aprovecho stove designers when they were
> >confronted with proof from university researchers that their beloved
stove,
> the Lorena, was not really "fuel efficient" although books published by
> Aprovecho claimed the savings were 50%. Over the last 20 years the
> understanding of how stoves work has grown to the point where there are
> substantive grounds of common understanding. Both how to clean up
combustion
> >and how to increase heat transfer to the pot are now generally accepted
> >engineering concepts.

1- LH- What! Did the stove testers learn how to use the stove before they
did the test? It may take a several uses to learn how to get the best
peformance.

> Dr. Larry Winiarski has come up with a set of design principles that can
be
> used in many different stoves. Larry likes to start out discussions of
stove
> design by saying that there is no such thing as a Rocket stove!

2- LH- If there is no such thing as a "Rocket Stove", maybe it should be
call it a "Rocket Burner", a brilliant consept that can be applied to a
viriety of stove applications.

> Stoves that
> use the Rocket design principles are always different depending on use and
> materials available. A mud stove and a two pot stainless steel stove with
> chimney can both be Rocket stoves. Larry's design principles follow this
> letter.
>
>
>
> I believe that the fastest and most successful way to design a stove that
> will be widely appreciated and used is to involve local women in the
design
> committee. When HELPS International was designing it's very successful
> griddle stove in Guatemala ten local women were responsible for adapting
the
> stove to their needs. The stove went through several important revisions
> before the whole committee loved the stove and was sure that it would be
> loved by other women. This process took about a year but I think that it
> makes sense to follow this pattern. Large companies always do product
> testing before introducing new products. Without product testing we can
not
> know for sure whether some important variable has been overlooked,
> forgotten.
>
> Insulating mud stoves is a good idea. The insulated combustion chamber can
> be coated with mud so that the appearance of the stove is the same. But
the
> insulating combustion chamber helps to reduce smoke, makes the stove much
> easier to light, faster to boil, and assists burning green wood. We have
> developed the following methods for making indigenous insulative
combustion
> chambers:
>
> 1.) 50% clay added to 50% sawdust or other burnable material
> 2.) 15% clay added to 85% perlite
> 3.) 15% clay added to 85% pumice
> 4.) 25% clay added to 75% vermiculite
> 5.) Using locally made floor tiles
>
> 6.) We are experimenting with charcoal/clay presently.
>
>
>
>
> These tiles or bricks or molded shapes are fired in a kiln. Floor tiles,
> usually red clay and porous in nature, have been used in Central America
> for 4 years without breaking in the combustion chambers of Rocket type
> stoves. The floor tile is surrounded by any lightweight insulation . In
> Guatemala these tiles are called "baldosa" and are inexpensive. I'm told
> that they are made also in Rwanda.
>
> Without testing we would not have been convinced that the Lorena was not
> fuel efficient. The boiling test, using the same pot every time, is
largely
> accepted as showing differences between stoves. Make bundles of wood that
> are the same weight, say a couple of pounds. Using the same pot 3/4 full
of
> water, say 10 pounds of water, burn the wood in the stove allowing 8600BTU
> per pound of wood and 1005BTU for a pound of water boiled away. The
sensible
> heat (rise in water temperature) added to the latent heat (calculated by
> weighing remaining water) is the amount of energy gotten into the pot. 2
> times 8600BTU's or 17,200BTU's is the total energy expended. Some folks
give
> a credit for charcoal remaining in the stove. But even a simple test like
> this will give designers an idea of fuel efficiency. Each test should be
> done a minimum of three times by a cook not involved with the project.
> (Expert stove testers can make their own stove perform remakably well
> without intending to effect the results. Inventors pride is a constant
> problem here at Aprovecho!)
>
3- LH- Lets not forget the stove owners pride. They should be able to get
almost as good a results as the inventor after some practice. Just a
suggestion, next time ask the stove tester to take the stove home and
cook dinner on it for a week before testing.
>
> The spirit of collaboration that is so evident in these conversations
shows
> the open minded committment of GTZ, ProBec and others to help those using
> stoves. It is a great pleasure to work in this atmosphere and it makes me
> confident that safer, cleaner and more efficient stoves are on their way
to
> those in need.
>
> Rocket Stove Principles
>
> Dr. Larry Winiarski
> Technical Director
> Aprovecho Research Center
> Apro@efn.org
>
> 1.) Insulate particularly the combustion chamber with low mass, heat
> resistant materials in order to keep the fire as hot as possible and not
to
> heat the higher mass of the stove body.
>
> 2.) Within the stove body, above the combustion chamber, use an insulated,
> upright chimney of a height that is about two or three times the diameter
> before extracting heat to any surface (griddle, pots, etc.).
>
> 3.) Heat only the fuel that is burning (and not too much). Burn the tips
of
> sticks as they enter the combustion chamber, for example. The object is
NOT
> to produce more gasses or charcoal than can be cleanly burned at the power
> level desired.
>
> 4.) Maintain a good air velocity through the fuel. The primary Rocket
stove
> principle and feature is using a hot, insulated, vertical chimney within
the
> stove body that increases draft.
>
> 5.) Do not allow too much or too little air to enter the combustion
chamber.
> We strive to have stoichiometric (chemically ideal) combustion: in
practice
> there should be the minimum excess of air supporting clean burning.
>
> 6.) The cross sectional area (perpendicular to the flow) of the combustion
> chamber should be sized within the range of power level of the stove.
> Experience has shown that roughly twenty-five square inches will suffice
for
> home use (four inches in diameter or five inches square). Commercial size
is
> larger and depends on usage.
>
> 7.) Elevate the fuel and distribute airflow around the fuel surfaces. When
> burning sticks of wood, it is best to have several sticks close together,
> not touching, leaving air spaces between them. Particle fuels should be
> arranged on a grate.
>
> 8.) Arrange the fuel so that air largely flows through the glowing coals.
> Too much air passing above the coals cools the flames and condenses oil
> vapors.
>
> 9.) Throughout the stove, any place where hot gases flow, insulate from
the
> higher mass of the stove body, only exposing pots, etc. to direct heat.
>
> 10.) Transfer the heat efficiently by making the gaps as narrow as
possible
> between the insulation covering the stove body and surfaces to be heated
but
> do this without choking the fire. Estimate the size of the gap by keeping
> the cross sectional area of the flow of hot flue gases constant.
EXCEPTION:
> When using a external chimney or fan the gaps can be substantially reduced
> as long as adequate space has been left at the top of the internal short
> chimney for the gasses to turn smoothly and distribute evenly. This is
> tapering of the manifold. In a common domestic griddle stove with external
> chimney, the gap under the griddle can be reduced to about one half inch
for
> optimum heat transfer.
>

4- LH- When wise people speek I listen.
Lanny Henson

>
> All Best,
>
> Dean Still
> Director
> Advanced Studies in Appropriate Technology
> Aprovecho Research Center
>
>

From lanny at ROMAN.NET Wed Feb 12 17:24:12 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing/ possible flow hood substitute
Message-ID: <WED.12.FEB.2003.142412.0800.LANNY@ROMAN.NET>

Emission testing /possible flow hood substitute.
http://www.lanny.us/test1.html Aprox 130KB
http://www.lanny.us/test6.jpg a 23k photo
Measuring the total output of emissions is difficult because it is hard to
measure the volume of the exhaust.

What if you captured 60 sec of exhaust fumes into a fixed volume then we
could calculate total output without measuring the cfms of the exhaust?

I used a 35 gallon (32+ aprox 3 gallons for the lid) trashcan as a fixed
volume and installed a can with a plastic lid as a port.
The port is large enough to fit over the stack when the trashcan is turned
upside down and there is enough space for the cooler air to be displaced
through the port as hot fumes rise to the top.
I was getting a different reading when the can was on its side that when
upright so I installed a dustpan through the lid as an air mixer.
I held the can over the stack for 60 sec and got a reading of 682 parts per
million.
Lanny

From psanders at ILSTU.EDU Wed Feb 12 17:24:14 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:13 2004
Subject: What is a stove?
In-Reply-To: <00ab01c2d2db$0469ab60$8c387f41@oemcomputer>
Message-ID: <WED.12.FEB.2003.162414.0600.PSANDERS@ILSTU.EDU>

At 10:28 AM 2/12/03 -0800, Lanny Henson wrote:
> Dear stove friends,
> >Larry likes to start out discussions of stove
> > design by saying that there is no such thing as a Rocket stove!
>
> 2- LH- If there is no such thing as a "Rocket Stove", maybe it should be
> call it a "Rocket Burner", a brilliant concept that can be applied to a
> variety of stove applications.
Stovers,

I agree with the above, and add. Many months back I posted to the
Stoves list that "stoves" have four (4) crucial elements/factors/types of
variables. They are closely interrelated in specific configurations and
practices, but they are quite distinct.

1. Fuels
2. Combustion chamber (MIGHT include chimney if the draft issue is
considered)
3. Stove structure (legs, plancha, body, chimney, hood, oven, pot-types
available, safety components, etc)
4. Cooking practices.

What Larry and Lanny mention about the ROCKET is that it is a great
"combustion chamber". Period. MANY varieties of stove structures (legs,
pot holders, hoods, big, small, etc.) can can be used with a good
combustion chamber.

Messages earlier this month have dealt with how people cook and what they
cook. This is where the ultimate test lies, but what might be a good
"complete stove combination" for one type of cooking might be a disaster
for another type.

"Combustion chambers" are numerous and varied. But watch out for blaming
(or praising) a "stove" (really the combustion chamber) because of issues
of fuels, structure and cooking practices.

And MANY messages on this stoves list serve mix and match the 4 elements
without distinguishing them clearly.

So, I agree with the Aprovecho folks. Rocket is a combustion chamber. And
my Juntos gasifer is a combustion chamber. And many others have combustion
chambers.

Some of "stove combustion chambers" have built-in "structure" along with
the combustion chamber. This can be very good, such as in Crispin's units
where the pot is directly over the combustion chamber and the side-walls
that surround the pot provide a ring-shaped chimney. But those side walls
and the pot itself are a single variation of "structure." If you change
the pot diameter but not the side walls (therefore a bigger gap), the
dynamics and efficiency of the combustion chamber may or may not be altered.

Please note that at the start I said that "chimney" can be part of
structure or an integral part of the combustion chamber (for required
draft). But a plancha or a pot or an oven or other "structure" should not
considered in evaluating a combustion chamber.

So, if we are to evaluate the combustion chambers, and assuming that we can
agree upon the fuels to be used, then let us make sure that the extra stuff
of stove structure does NOT influence the test results. If we are testing
for ONE stove structure (such as a plancha size x by y by z thick), THEN we
can compare the aspects of the combustion chambers.

Paul

 

 

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From mheat at MHA-NET.ORG Wed Feb 12 17:36:13 2003
From: mheat at MHA-NET.ORG (Norbert Senf)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing/ possible flow hood substitute
In-Reply-To: <00bf01c2d2e5$d6283c20$8c387f41@oemcomputer>
Message-ID: <WED.12.FEB.2003.173613.0500.MHEAT@MHANET.ORG>

At 02:24 PM 2003-02-12 -0800, Lanny Henson wrote:
>Emission testing /possible flow hood substitute.
>http://www.lanny.us/test1.html Aprox 130KB
>http://www.lanny.us/test6.jpg a 23k photo
>Measuring the total output of emissions is difficult because it is hard to
>measure the volume of the exhaust.
>
>What if you captured 60 sec of exhaust fumes into a fixed volume then we
>could calculate total output without measuring the cfms of the exhaust?

This may be slightly off topic, but the most common EPA emissions method
uses a dilution tunnel. Basically you have a hood above the chimmney exit,
and are diluting the exhaust with air in order to condense the
semi-volatiles so that you can get a real-world particulate number.

If you can measure the flow out your exhaust hood, and the air flow into
your stove, you might have a very similar situation to a dilution tunnel.
In the dilution tunnel method, they do a traverse across the pipe diameter
with a pitot tube to get the tunnel flow.

Best ....... Norbert

From psanders at ILSTU.EDU Wed Feb 12 17:44:22 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:13 2004
Subject: Emission testing/ use of instruments
In-Reply-To: <00bf01c2d2e5$d6283c20$8c387f41@oemcomputer>
Message-ID: <WED.12.FEB.2003.164422.0600.PSANDERS@ILSTU.EDU>

Hi,

A question about emissions testing:

Can the collection end of the testing instrument simply be held in the
stream of the emissions and get a valid reading that way? If not, why
not, and could the reading from such a simple test be correlated to the
"hood/bag/bucket" results so we could see a table or graph of readings from
different methods that measure the same emission stream.

Paul

 

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Wed Feb 12 17:45:27 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:14 2004
Subject: Recommend instruments.
In-Reply-To: <00bf01c2d2e5$d6283c20$8c387f41@oemcomputer>
Message-ID: <WED.12.FEB.2003.164527.0600.PSANDERS@ILSTU.EDU>

Stovers:

Does anyone have recommendations about what CO measurer and what
temperature measurers (thermometers) are appropriate and low priced. For
example, at the MSC website www.mscdirect.com info is available, but
I am not sure what is best.

Price to be at the low end!!!

Thanks in advance.

Paul
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From pverhaart at OPTUSNET.COM.AU Wed Feb 12 20:37:36 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:14 2004
Subject: Emission testing/ possible flow hood substitute
In-Reply-To: <00bf01c2d2e5$d6283c20$8c387f41@oemcomputer>
Message-ID: <THU.13.FEB.2003.113736.1000.PVERHAART@OPTUSNET.COM.AU>

Hi Lanny,

Some questions that came up while reading your dustbin report.

1. How do you know the dustbin is full with pure exhaust (no remaining
air mixed in)?

2. What have you found out that you could not have found out by
inserting the measuring probe into the chimney?

Best regards,

Peter Verhaart

At 14:24 12/02/03 -0800, you wrote:
>STOVES@LISTSERV.REPP.ORG

From psanders at ILSTU.EDU Wed Feb 12 22:51:17 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:14 2004
Subject: "Boiling Point" and peer reviewed articles Re: [hedon] BP49 -
request for articles
In-Reply-To: <02E01CE12537D5118F2B0002A550DDC7017F23CD@itdg-mail>
Message-ID: <WED.12.FEB.2003.215117.0600.PSANDERS@ILSTU.EDU>

Liz

I did not see your message on the Stoves list serve, so I am forwarding it
to the Stovers.

Below is a suggestion:

For those in the academic realm, it would be nice if "Peer Reviewed" could
be added in the caption/header to SOME of the articles. Of course that
means that a peer review process would need to be instated for those who
would want to undergo that level of pre-publication examination.

Perhaps this has already been discussed (and perhaps rejected). But maybe
it would be appropriate considering the long history of BP in the field.

Sorry I could not help implement such a process. I am a professor, but of
geography. I am a novice about serious stoves publications. But certainly
there are those on this list serve and elsewhere who could qualify as
reviewers of merit.

Keep up the GREAT work, and I hope that many Stovers send items for you to
publish, either with or without peer review concerns.

Paul

At 05:16 PM 2/12/03 +0000, Liz Bates wrote:

>Hello everyone
>You may have noticed that there was a long delay between BP47 and BP48. We
>would really love to get publication back on track, now that we know we have
>just enough funds to cover the next issue. For this reason, can I please
>invite you to consider writing an article for:
>
>Boiling Point 49 - Desertification, forestry and household energy
>
>Desertification is related to household energy in two ways: Critically, the
>abuse of forest resources for non-energy purposes can impact on essential
>fuelwood supplies for basic energy needs. Where forest resources are already
>vulnerable, use of woodfuel, especially where it involves tree-felling, can
>exacerbate this situation and lead to desertification. Pro-poor policy
>decisions can have a major impact, and this issue will look at both policy
>initiatives and field-level mitigation to address the effects of
>desertification. Ways to alleviate desertification by use of fossil fuels
>will also be considered.
>
>Boiling Point is now sent out to around 2000 addresses, where we know it is
>read by several people per copy. Most of the readership are small NGOs, but
>we also send it to many educational establishments and policy-makers. In
>terms of dissemination, this means that any findings which you share can
>reach a large and relevant audience - do consider writing for this edition.
>
>Articles should be no more than 1500 words in length. Illustrations, such as
>drawings, photographs, graphs and bar charts are essential - especially for
>the majority of our readers for whom English is a second language.
>
>I will be away from my desk till the end of February, and would love to come
>back to find a flood of wonderful articles (or promises of them) by then.
>
>Please send articles to me by email or on disc (or hard copy) to:
>Boiling Point editor
>ITDG
>Schumacher Centre for Technology and Development
>Bourton on Dunsmore
>Rugby CV23 9QZ
>UK
>
>Email: Boiling.Point@itdg.org.uk <mailto:boiling.point@itdg.org.uk>
>
>
> > Liz Bates
> > lizb@ITDG.org.uk
> > Intermediate Technology Development Group
> > Schumacher Centre for Technology Development
> > Bourton Hall
> > Bourton On Dunsmore
> > Warwickshire
> > CV23 9QZ
> > Tel: +44 - 01926 634400
> > Fax: +44 - 01926 634401
> > www.itdg.org
> >
> > Company Reg. No 871954, England
> > Charity No 247257
> >
> >
> >
> >
> >
> >
> >
>This email and any files transmitted with it are confidential and intended
>solely for the use of the individuals or entity to whom they are addressed.
>ITDG and it subsidiaries(ITC and ITDG Publishing) cannot accept liability or
>contractual inferences for statements which are clearly the senders own and
>not made on behalf of ITDG or it subsidiaries(ITC and ITDG Publishing).
>
>----------
>Does your organisation feature on the Shell Foundation online database?
>Take a look at http://ecoharmony.net/hedon/org.php to find out more.
>
>Please feel free to forward this mail to any of your colleagues or
>business partners. We rely on users to spread the word about HEDON to the
>entire Household Energy community. In addition, please consider adding
>your own material to the HEDON web page resources. This is a simple
>process and can go a long way towards generating publicity for your
>activites among a select audience of professionals.
>
>For more information about HEDON visit:
>http://ecoharmony.net/hedon
>
>NOTE: Advertisements in this message have been added by Yahoo Groups who
>provides us with free email group services. HEDON does not endorse
>products or support the advertisements in any way.
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From dstill at EPUD.NET Wed Feb 12 03:52:46 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:14 2004
Subject: What is a stove?
Message-ID: <WED.12.FEB.2003.005246.0800.DSTILL@EPUD.NET>

Dear Paul,

No, the Rocket stove is more than a burner, it includes strategies for
improving heat transfer as well. In fact, heat transfer is mostly
responsible for fuel efficiency. Even open fires can burn pretty cleanly.
Using less wood can be independent of the combustion chamber. Sam Baldwin
put a skirt around the pot and achieved high fuel efficiency. Larry' stove
is perhaps more complete because strategies for clean combustion are coupled
to getting a large percentage of heat into food (Cooking) room (Heating)
water (Bathing), etc.

Here again are Larry's design characteristics:

All Best,

Dean

Rocket Stove Principles

Dr. Larry Winiarski
Technical Director
Aprovecho Research Center
Apro@efn.org

1.) Insulate particularly the combustion chamber with low mass, heat
resistant materials in order to keep the fire as hot as possible and not to
heat the higher mass of the stove body.

2.) Within the stove body, above the combustion chamber, use an insulated,
upright chimney of a height that is about two or three times the diameter
before extracting heat to any surface (griddle, pots, etc.).

3.) Heat only the fuel that is burning (and not too much). Burn the tips of
sticks as they enter the combustion chamber, for example. The object is NOT
to produce more gasses or charcoal than can be cleanly burned at the power
level desired.

4.) Maintain a good air velocity through the fuel. The primary Rocket stove
principle and feature is using a hot, insulated, vertical chimney within the
stove body that increases draft.

5.) Do not allow too much or too little air to enter the combustion chamber.
We strive to have stoichiometric (chemically ideal) combustion: in practice
there should be the minimum excess of air supporting clean burning.

6.) The cross sectional area (perpendicular to the flow) of the combustion
chamber should be sized within the range of power level of the stove.
Experience has shown that roughly twenty-five square inches will suffice for
home use (four inches in diameter or five inches square). Commercial size is
larger and depends on usage.

7.) Elevate the fuel and distribute airflow around the fuel surfaces. When
burning sticks of wood, it is best to have several sticks close together,
not touching, leaving air spaces between them. Particle fuels should be
arranged on a grate.

8.) Arrange the fuel so that air largely flows through the glowing coals.
Too much air passing above the coals cools the flames and condenses oil
vapors.

9.) Throughout the stove, any place where hot gases flow, insulate from the
higher mass of the stove body, only exposing pots, etc. to direct heat.

10.) Transfer the heat efficiently by making the gaps as narrow as possible
between the insulation covering the stove body and surfaces to be heated but
do this without choking the fire. Estimate the size of the gap by keeping
the cross sectional area of the flow of hot flue gases constant. EXCEPTION:
When using a external chimney or fan the gaps can be substantially reduced
as long as adequate space has been left at the top of the internal short
chimney for the gasses to turn smoothly and distribute evenly. This is
tapering of the manifold. In a common domestic griddle stove with external
chimney, the gap under the griddle can be reduced to about one half inch for
optimum heat transfer.

All Best,

Dean Still
Director
Advanced Studies in Appropriate Technology
Aprovecho Research Center

From crispin at NEWDAWN.SZ Thu Feb 13 04:45:21 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:14 2004
Subject: Latest from New Dawn
Message-ID: <THU.13.FEB.2003.114521.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

The conference in the Phillipines on the commercialisation of improved cook
stoves starts in a few days. We (meaning Rina King who is on her way there
now) will show off the commercial version of the single pot cooker whch is
called a "Vesto". She will deliver a paper on the plan of how we intend to
get thousands of people to fork out their own money to buy an un-subsidized
improved stove.

The paper will presumably be available to anyone who wants to read it after
her presentation. I think you will be impressed.

The colours and artwork that will be printed on the stove have been agreed
upon. This includes a little flame and a big one to indicate where to move
the 'volume control', contact info etc. We are going to sell them at $31.30
initially.

The possible deletion of the secondary controller is being considered in
that although it allows the stove to be use as a low power gassifier, the
cost of the part may not justify the minor fuel saving one gains by turning
back the secondary air in low power conditions. Basically it prevents
excess secondary air entering the combustion chamber. If the amount of
excess air chilling the fire is not significant enough to save a reasonable
valuable fuel, then it isn't worth spending money in it, even though if
gives a theoretically better burn. I would rather lose the little bit of
fuel, lose the part and lower the price.

This is the sort of decision that is made when getting out of the lab and
'going commercial'. It already uses so little fuel for ordinary cooking,
and burns so cleanly that I think we can afford to drop the variability of
the secondary air. It actually has three types of secondary air entering
the chamber and the secondary controller affects only one of them.

What do other people think about going for textbook correct combustion v.s.
lower cost?

Regards
Crispin

PS We could always offer it as an optional extra!

From lanny at ROMAN.NET Thu Feb 13 10:36:51 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:14 2004
Subject: Emission testing/ possible flow hood substitute
Message-ID: <THU.13.FEB.2003.073651.0800.LANNY@ROMAN.NET>

Hey Peter,
1. I am not trying to fill with pure exhaust but capture 60 sec of exhaust.
2. I am thinking that to get the total amount I need the concentration of
the exhaust and the volume of the exhaust.
The concentration is easy to measure, just stick a probe it the chimney.
Measuring the volume is not that easy without some expensive equipment. As a
cheep alternative I thought that I could catch 60 sec worth of exhaust in a
known volume then the concentration X the known volume would tell me the
grams of co per min. Right?

Lanny

----- Original Message -----
From: Peter Verhaart <pverhaart@OPTUSNET.COM.AU>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, February 12, 2003 5:37 PM
Subject: Re: [STOVES] Emission testing/ possible flow hood substitute

> Hi Lanny,
>
> Some questions that came up while reading your dustbin report.
>
> 1. How do you know the dustbin is full with pure exhaust (no
remaining
> air mixed in)?
>
> 2. What have you found out that you could not have found out by
> inserting the measuring probe into the chimney?
>
> Best regards,
>
> Peter Verhaart
>
> At 14:24 12/02/03 -0800, you wrote:
> >STOVES@LISTSERV.REPP.ORG
>

From ronallarson at QWEST.NET Thu Feb 13 09:32:34 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:14 2004
Subject: Latest from New Dawn
In-Reply-To: <005801c2d345$9133f220$2a47fea9@md>
Message-ID: <THU.13.FEB.2003.073234.0700.RONALLARSON@QWEST.NET>

Crispin:

This is to take up your request for comments in the last line below and add
a few more thoughts.

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of Crispin
>Sent: Thursday, February 13, 2003 2:45 AM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: [STOVES] Latest from New Dawn
>
>
>Dear Stovers
>
>The conference in the Phillipines on the commercialisation of improved cook
>stoves starts in a few days.

RWL: I hope Rina and others able to attend will spread the word about this
list and all will report back on new concepts (like Crispin's) discussed
there.

>We (meaning Rina King who is on her way there
>now) will show off the commercial version of the single pot cooker which is
>called a "Vesto".

(RWL): From earlier off-line communication with Crispin, I learned this
about the name:

">>Does "Vesto" carry any local language significance?
>
>No, it is a contraction of Variable Energy Stove, or Very Efficient Stove,
>just a name that we hope is catchy, and it will be known as a Vesto, not a
>Vesto Stove. A Vesto is a type of device. Many things can be attached to
>it like BBQ and roasting, oven and space heating, but the basic
>unit will be called a Vesto."

>She will deliver a paper on the plan of how we intend to
>get thousands of people to fork out their own money to buy an un-subsidized
>improved stove.
>
>The paper will presumably be available to anyone who wants to read it after
>her presentation. I think you will be impressed.
>
>The colours and artwork that will be printed on the stove have been agreed
>upon. This includes a little flame and a big one to indicate where to move
>the 'volume control', contact info etc. We are going to sell them
>at $31.30 initially.

(RWL): I congratulate Crispin for getting this far in his marketing. I
hope he will tell us on this list about likely shipping charges - as I would
like to buy one of the first.
>
>The possible deletion of the secondary controller is being considered in
>that although it allows the stove to be use as a low power gassifier, the
>cost of the part may not justify the minor fuel saving one gains by turning
>back the secondary air in low power conditions. Basically it prevents
>excess secondary air entering the combustion chamber. If the amount of
>excess air chilling the fire is not significant enough to save a reasonable
>valuable fuel, then it isn't worth spending money in it, even though if
>gives a theoretically better burn. I would rather lose the little bit of
>fuel, lose the part and lower the price.

(RWL): This would seem to be a quite low cost component out of the total.
Can you explain more about the phrase "low power gassifier"? If this
additional part allows charcoal production, I would argue strongly for
retaining the secondary air controller.
My main concern with secondary air control has been that one could
inadvertently close it too much at the wrong time and snuff out the
combustion. But this should only happen once when one first starts using a
pyrolysis/gassifier stove.
As I think you are the only one who has the ability to control secondary
air completely - I hope you can share what the efficiency gains would be. I
never did tests, but it seemed that the amount of secondary air hole closure
was not too critical, but that I always got better efficiency at lower power
levels (controlled of course only by the primary air supply).
So in sum, even if the tests show a truly small influence of excess
secondary air, I would still like personally to keep the option - for
reasons of ease in charcoaling. I am just guessing that you will find that
the small extra cost is worth it - and maybe also for efficiency reasons.
I have intentions of doing something similar (for reasons like your
explored below)- and would definitely now want to add a (maybe optional?)
control feature for secondary air.

>
>This is the sort of decision that is made when getting out of the lab and
>'going commercial'. It already uses so little fuel for ordinary cooking,
>and burns so cleanly that I think we can afford to drop the variability of
>the secondary air. It actually has three types of secondary air entering
>the chamber and the secondary controller affects only one of them.

(RWL): This not clear. I presume that you mean some secondary air is
coming in with your primary air from below. The main (?) secondary is what
is coming in higher. But is the third some sort of down draft from the top?
Can you estimate the magnitude of this? Do you consider this undesirable?

>
>What do other people think about going for textbook correct combustion vs..
>lower cost?
>
(RWL): The key phrase here in this e-mail may be this one about "textbook
correct". I think from this that you mean two things - preheating and close
to stochiometric conditions. I visited a coal-fired power plant last week
and forgot to ask about the former (but I am pretty sure was occurring) -
but did ask how much excess air they used and was told 2.5% (I presume that
much "unspent" oxygen in the exhaust stream - but he may have meant that
97.5% of the oxygen was consumed. I will try to determine better his
response). The engineer said they needed to leave that much to get to the
required low emission levels. (This combustion chamber was seven stories
high and we were able to look in at the combustion at the highest level.
Very impressive.) I am sure our (mostly future) tests will confirm that we
can't get anywhere close to what a 200 MW coal plant can achieve - but still
I think we should be trying and we should be testing this to find out where
we are. Your secondary air control is needed for that testing.
But mostly I hope you will explain more about preheating and any further
thoughts you have on its importance - about which this list has not talked
enough, I fear.
My hope still is that you will retain the secondary air control
capability - if not for every model - and even if it cost $5.00 more - I
would buy it sight unseen.

Thanks for a very important posting.

Ron

>Regards
>Crispin
>
>PS We could always offer it as an optional extra!
>
>

From psanders at ILSTU.EDU Thu Feb 13 16:33:56 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:14 2004
Subject: What is a stove?
In-Reply-To: <003b01c2d275$bad19860$7e1e6c0c@default>
Message-ID: <THU.13.FEB.2003.153356.0600.PSANDERS@ILSTU.EDU>

Dean and all,

What you have is YOUR stove, and who am I to say it is only a burner.

BUT, the earlier messages from Aprovecho people have Larry and Lanny saying
do not call it a "stove" when it is really most importantly a combustion
chamber. I was only agreeing with that statement.

Having re-read the "Rocket Stove Principles" that you included, I will
point out the following:

1. Only items 9 and 10 actually deal with what I call "stove
structure." The first 8 principles relate to the combustion unit.

NOTE: A revision of my earlier terminology: I should call it a
combustion UNIT so that the "chamber" can have double walls and insulation etc.

2. The internal upright chimney (see #2 of the principles) is an important
part to the combustion unit. It is defined as being before (below) where
the heat reaches the area where the cooking takes place. It might look
like it is in the "structure" of the stove body, but that is simply the
encasing and supporting of that chimney.

3. The combustion unit should be kept hot. This is done with insulation,
including the new work on special bricks, and packing ash or other
insulation around the combustion chamber. Every combustion chamber has
some amount of support and insulation. Some, such as mine and Crispin's,
have two concentric metal walls with air flowing between them for
pre-heating air. Yes, combustion UNIT is the better term.

4. Concerning the adding of the metal skirt around the cooking pot, I
mentioned in my previous message that the skirt can assist with draft and
is, like a chimney-after-the-cooking, a part of stove structure that can
assist the combustion.

If Aprovecho has a Rocket "device" that can be used with a
pot-with-skirt and also one with a plancha-and-chimney, and perhaps other
variations, then what is the "Rocket" if it is not the common element that
is the combustion unit? Oh yes, the first Rocket Stove that I ever saw was
the square tin-can version. I am sure you do not want people to associate
"Rocket" with ONLY that version.

My work on the Juntos gasifier is clearly on the combustion-unit
aspect. If a Juntos unit is placed into one of your Plancha-and-chimney"
units, what should we call it? "Juntos in plancha" stove would sound
correct, as would for your arrangement the "Rocket in plancha" stove that
would distinguish it from the "Rocket in tin-can" version and the "Rocket
with skirted-pot" version and the stainless steel 2-pot version.

Crispin is good at having a new name for each significant variation of his
combustion unit with corresponding stove structure. In some ways that is
confusing, but in other ways it prevents confusion, such as "what is a
Rocket Stove." Each of us can name and market as we choose. But when we
discuss the efficiency of any "stove" or if we compare different "stoves",
let's be very clear about the stove structure.

Stovers: Written words do not always show the smiles and good
intentions. Dean and I met at the ETHOS meeting last month and we can now
"agrue" via e-mail with 170 others reading. We are friends and we expect
to bring mutual benefits to each other.

P.S. I am extremely impressed by the Rocket (combustion unit) and by the
way it has been incorporated into fully functional "stoves."

Paul

At 12:52 AM 2/12/03 -0800, Dean Still wrote:
>Dear Paul,
>
>No, the Rocket stove is more than a burner, it includes strategies for
>improving heat transfer as well. In fact, heat transfer is mostly
>responsible for fuel efficiency. Even open fires can burn pretty cleanly.
>Using less wood can be independent of the combustion chamber. Sam Baldwin
>put a skirt around the pot and achieved high fuel efficiency. Larry' stove
>is perhaps more complete because strategies for clean combustion are coupled
>to getting a large percentage of heat into food (Cooking) room (Heating)
>water (Bathing), etc.
>
>Here again are Larry's design characteristics:
>
>All Best,
>
>Dean
>
>Rocket Stove Principles
>
>Dr. Larry Winiarski
>Technical Director
>Aprovecho Research Center
>Apro@efn.org
>
>1.) Insulate particularly the combustion chamber with low mass, heat
>resistant materials in order to keep the fire as hot as possible and not to
>heat the higher mass of the stove body.
>
>2.) Within the stove body, above the combustion chamber, use an insulated,
>upright chimney of a height that is about two or three times the diameter
>before extracting heat to any surface (griddle, pots, etc.).
>
>3.) Heat only the fuel that is burning (and not too much). Burn the tips of
>sticks as they enter the combustion chamber, for example. The object is NOT
>to produce more gasses or charcoal than can be cleanly burned at the power
>level desired.
>
>4.) Maintain a good air velocity through the fuel. The primary Rocket stove
>principle and feature is using a hot, insulated, vertical chimney within the
>stove body that increases draft.
>
>5.) Do not allow too much or too little air to enter the combustion chamber.
>We strive to have stoichiometric (chemically ideal) combustion: in practice
>there should be the minimum excess of air supporting clean burning.
>
>6.) The cross sectional area (perpendicular to the flow) of the combustion
>chamber should be sized within the range of power level of the stove.
>Experience has shown that roughly twenty-five square inches will suffice for
>home use (four inches in diameter or five inches square). Commercial size is
>larger and depends on usage.
>
>7.) Elevate the fuel and distribute airflow around the fuel surfaces. When
>burning sticks of wood, it is best to have several sticks close together,
>not touching, leaving air spaces between them. Particle fuels should be
>arranged on a grate.
>
>8.) Arrange the fuel so that air largely flows through the glowing coals.
>Too much air passing above the coals cools the flames and condenses oil
>vapors.
>
>9.) Throughout the stove, any place where hot gases flow, insulate from the
>higher mass of the stove body, only exposing pots, etc. to direct heat.
>
>10.) Transfer the heat efficiently by making the gaps as narrow as possible
>between the insulation covering the stove body and surfaces to be heated but
>do this without choking the fire. Estimate the size of the gap by keeping
>the cross sectional area of the flow of hot flue gases constant. EXCEPTION:
>When using a external chimney or fan the gaps can be substantially reduced
>as long as adequate space has been left at the top of the internal short
>chimney for the gasses to turn smoothly and distribute evenly. This is
>tapering of the manifold. In a common domestic griddle stove with external
>chimney, the gap under the griddle can be reduced to about one half inch for
>optimum heat transfer.
>
>
>All Best,
>
>Dean Still
>Director
>Advanced Studies in Appropriate Technology
>Aprovecho Research Center

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Thu Feb 13 16:50:31 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:14 2004
Subject: Combustion of CO
Message-ID: <THU.13.FEB.2003.155031.0600.PSANDERS@ILSTU.EDU>

Stovers,

Carbon monoxide ( CO ) is combustible to generate heat. I believe that a
stove produces excessive CO when it is burning of charcoal, correct?, or
when a stove's air supply is reduced, right?

So, what is required to be able to combust it?

Variables include:

Concentration of CO

Temperature of the CO (including temperature after the O2 in the air is
introduced.)

Ignition spark / flame??

Other factors??

If we have this information, then we can consider how to attain those
conditions via arrangement of stove components.

Thanks in advance.

Paul
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From kchisholm at CA.INTER.NET Thu Feb 13 17:31:29 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:14 2004
Subject: Latest from New Dawn
Message-ID: <THU.13.FEB.2003.183129.0400.KCHISHOLM@CA.INTER.NET>

Dear Crispin

You raise a very important practical consideration.

My feeling is that the ideal situation would be to proceed as you propose
but offer the efficiency improvement hardware as an optional extra, if it
could be done in a way that the extra hardware could be retrofitted.

Note also, that you should really be asking these questions to your actual
Customers.... not "people from away" who are not in the Market for one of
your stoves.

The best way to address these questions is to make both stoves initially,
and let your Markets tell you what they want.

Best wishes

Kevin

----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, February 13, 2003 5:45 AM
Subject: [STOVES] Latest from New Dawn

> Dear Stovers
>
> The conference in the Phillipines on the commercialisation of improved
cook
> stoves starts in a few days. We (meaning Rina King who is on her way
there
> now) will show off the commercial version of the single pot cooker whch is
> called a "Vesto". She will deliver a paper on the plan of how we intend
to
> get thousands of people to fork out their own money to buy an
un-subsidized
> improved stove.
>
> The paper will presumably be available to anyone who wants to read it
after
> her presentation. I think you will be impressed.
>
> The colours and artwork that will be printed on the stove have been agreed
> upon. This includes a little flame and a big one to indicate where to
move
> the 'volume control', contact info etc. We are going to sell them at
$31.30
> initially.
>
> The possible deletion of the secondary controller is being considered in
> that although it allows the stove to be use as a low power gassifier, the
> cost of the part may not justify the minor fuel saving one gains by
turning
> back the secondary air in low power conditions. Basically it prevents
> excess secondary air entering the combustion chamber. If the amount of
> excess air chilling the fire is not significant enough to save a
reasonable
> valuable fuel, then it isn't worth spending money in it, even though if
> gives a theoretically better burn. I would rather lose the little bit of
> fuel, lose the part and lower the price.
>
> This is the sort of decision that is made when getting out of the lab and
> 'going commercial'. It already uses so little fuel for ordinary cooking,
> and burns so cleanly that I think we can afford to drop the variability of
> the secondary air. It actually has three types of secondary air entering
> the chamber and the secondary controller affects only one of them.
>
> What do other people think about going for textbook correct combustion
v.s.
> lower cost?
>
> Regards
> Crispin
>
> PS We could always offer it as an optional extra!
>

From koopmans at LOXINFO.CO.TH Thu Feb 13 18:43:24 2003
From: koopmans at LOXINFO.CO.TH (koopmans@LOXINFO.CO.TH)
Date: Tue Aug 10 18:30:14 2004
Subject: Latest from New Dawn
Message-ID: <FRI.14.FEB.2003.064324.0700.>

Difficult to say but in the region where I live (S.E.Asia) I probably would go for lower cost. In quite a few cases it has been found that people rareley use dampers as the cook has not only to take care of cooking but at the same time often is busy with other tasks (prepartion of food, taking care of small kids, etc.) that little time remain to adjust airflows into the stove.

Regards,

Auke

Will be in the Philippines as well and hope to learn a lot from your efforts to make clean and fuel saving stoves.

>From: Crispin <crispin@newdawn.sz>
>Date: Thu, 13 Feb 2003 11:45:21 +0200
>Subject: [STOVES] Latest from New Dawn
>
>
>Dear Stovers
>
>The conference in the Phillipines on the commercialisation of improved cook
>stoves starts in a few days. We (meaning Rina King who is on her way there
>now) will show off the commercial version of the single pot cooker whch is
>called a "Vesto". She will deliver a paper on the plan of how we intend to
>get thousands of people to fork out their own money to buy an un-subsidized
>improved stove.
>
>The paper will presumably be available to anyone who wants to read it after
>her presentation. I think you will be impressed.
>
>The colours and artwork that will be printed on the stove have been agreed
>upon. This includes a little flame and a big one to indicate where to move
>the 'volume control', contact info etc. We are going to sell them at $31.30
>initially.
>
>The possible deletion of the secondary controller is being considered in
>that although it allows the stove to be use as a low power gassifier, the
>cost of the part may not justify the minor fuel saving one gains by turning
>back the secondary air in low power conditions. Basically it prevents
>excess secondary air entering the combustion chamber. If the amount of
>excess air chilling the fire is not significant enough to save a reasonable
>valuable fuel, then it isn't worth spending money in it, even though if
>gives a theoretically better burn. I would rather lose the little bit of
>fuel, lose the part and lower the price.
>
>This is the sort of decision that is made when getting out of the lab and
>'going commercial'. It already uses so little fuel for ordinary cooking,
>and burns so cleanly that I think we can afford to drop the variability of
>the secondary air. It actually has three types of secondary air entering
>the chamber and the secondary controller affects only one of them.
>
>What do other people think about going for textbook correct combustion v.s.
>lower cost?
>
>Regards
>Crispin
>
>PS We could always offer it as an optional extra!

From Carefreeland at AOL.COM Thu Feb 13 20:13:30 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:14 2004
Subject: Latest from New Dawn
Message-ID: <THU.13.FEB.2003.201330.EST.>

In a message dated 2/13/03 4:53:25 AM Eastern Standard Time,
crispin@newdawn.sz writes:

> Dan's comment
>
> What do other people think about going for textbook correct combustion v.s.
> lower cost?
>
> Regards
> Crispin
>
> PS We could always offer it as an optional extra!
>

> Crispin, do that, options give people a feeling of having control over a
buying decision. Options also give people something to discuss about your
stove ;-)
Your stover buddy,
Daniel Dimiduk

From pverhaart at OPTUSNET.COM.AU Fri Feb 14 00:34:19 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:14 2004
Subject: Fwd: Re: [STOVES] Emission testing/ possible flow hood substitute
Message-ID: <FRI.14.FEB.2003.153419.1000.PVERHAART@OPTUSNET.COM.AU>

>Date: Fri, 14 Feb 2003 15:20:42 +1000
>To: Lanny Henson <lanny@ROMAN.NET>
>From: Peter Verhaart <pverhaart@optusnet.com.au>
>Subject: Re: [STOVES] Emission testing/ possible flow hood substitute
>
>Lanny,
>
>Why would you need the volume?
>In order to measure/calculate that, you would need to do both eg stick a
>probe into the chimney as well as do your thing with the dustbin.
>The ratio of CO or CO2 concentrations in dustbin and chimney would give
>you the proportion of fluegas in the dustbin. With known volume of the
>latter you could find the volume of fluegas produced during your unit time.
>
>Cheers,
>
>Peter Verhaart
>
>
>At 07:36 13/02/03 -0800, you wrote:
>>Hey Peter,
>>1. I am not trying to fill with pure exhaust but capture 60 sec of exhaust.
>>2. I am thinking that to get the total amount I need the concentration of
>>the exhaust and the volume of the exhaust.
>>The concentration is easy to measure, just stick a probe it the chimney.
>>Measuring the volume is not that easy without some expensive equipment. As a
>>cheep alternative I thought that I could catch 60 sec worth of exhaust in a
>>known volume then the concentration X the known volume would tell me the
>>grams of co per min. Right?
>>
>>Lanny

From lanny at ROMAN.NET Fri Feb 14 10:45:39 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:14 2004
Subject: Emission testing/ possible flow hood substitute
Message-ID: <FRI.14.FEB.2003.074539.0800.LANNY@ROMAN.NET>

Hey Peter,
See below.

----- Original Message -----
From: Peter Verhaart <pverhaart@optusnet.com.au>
To: Lanny Henson <lanny@ROMAN.NET>
Sent: Thursday, February 13, 2003 9:20 PM
Subject: Re: [STOVES] Emission testing/ possible flow hood substitute

> Lanny,
>
> Why would you need the volume?

1-LH- Because 8 cfm of exhaust at 500 ppm CO would have twice as much CO as
4 cfm at 500 ppm. Right?
And the power output should be considered? and other factors?

Anyone got an "Idiot's Guide To Emission Testing"?

> In order to measure/calculate that, you would need to do both eg stick a
> probe into the chimney as well as do your thing with the dustbin.
> The ratio of CO or CO2 concentrations in dustbin and chimney would give
you
> the proportion of fluegas in the dustbin. With known volume of the latter
> you could find the volume of fluegas produced during your unit time.

2-LH- Good idea, I did not think of that.
Thanks for your input.

Lanny Henson

> Cheers,
>
> Peter Verhaart
>
>
> At 07:36 13/02/03 -0800, you wrote:
> >Hey Peter,
> >1. I am not trying to fill with pure exhaust but capture 60 sec of
exhaust.
> >2. I am thinking that to get the total amount I need the concentration
of
> >the exhaust and the volume of the exhaust.
> >The concentration is easy to measure, just stick a probe it the chimney.
> >Measuring the volume is not that easy without some expensive equipment.
As a
> >cheep alternative I thought that I could catch 60 sec worth of exhaust in
a
> >known volume then the concentration X the known volume would tell me the
> >grams of co per min. Right?
> >
> >Lanny
>
>

From lanny at ROMAN.NET Fri Feb 14 23:43:23 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:14 2004
Subject: Cooking Brown Rice Test
Message-ID: <FRI.14.FEB.2003.204323.0800.LANNY@ROMAN.NET>

Dear Stove Friends,
I did a test to see how my stove actually cooks.
About 218 grams of wood cooked 8 servings of rice.

For cooking test #1 stove #6,
I cooked brown rice. (Brown rice requires about 45 min to cook. White
milled rice requires about 20 min. If you are using the haybox heat and hold
method (bring to boil and hold in an insulated wrap or container till done)
then it may take a little longer).

Brown rice = ? liter volume (397g or 14oz) the package said 8-(? cup= 59ml=
42g) servings.
Water = 1 liter of 6.1 degC = 43 degF water.
Some salt and oil

For fuel I used:
218.5 grams of wood
20 grams -a whole sheet of news paper to charge the stack to get a quick
draft.
A ? sheet (10g) also works fine. This step is not necessary.
http://www.lanny.us/cs6n.jpg 26KB charging stack.
http://www.lanny.us/cs6m.jpg 29KB for quick draft.
3 grams of charcoal
I had 10.4 g of charcoal left over after the cooking test.

I kept a small hot fire and took 39 min to boil. Then I cooked another 10
min and shut down the stove. In 1.5 hours I checked the rice. It was warm
and done but a little dry. I had to add some water and reheat a little on
my electric stove.

So about 218 grams of wood cooked 8 servings of rice

A few things:
1- Rain had leaked into the stove and wet the insulation so I had some loss
there until it dried. I saw steam escaping for a while.
2- I failed to insulate the pot sleeve on this stove like I did on #4 and I
the outer shell felt hotter. I will insulate the sleeve on #6B. One thing
that I like about these stoves is that they are quick and easy to build. The
insulated pot sleeve appears more important that thought. On another burn
without the insulation on a windy day, 540 grams of wood failed to boil 6
liters of water. My strategy was to use a small hot fire with a little more
time but it took a medium fire to overcome the heat loss though the stove
body.
3- I added rice and cold water to the pot then heated both. As the stove
began to heat up I noticed (by the finger dip method) that I was not getting
much heat transfer into the water. The rice had sank to the bottom and
seemed to act like a layer of insulation between the pot and the water.
Stirring seemed to help distribute the heat. I had thought that by adding
the rice first I could get a little extra cooking time as the water was
coming to a boil. But now I am thinking that heating the water first before
adding the rice may be more efficient. Any one else noticed this?
A science project for someone?

Lanny Henson

From english at KINGSTON.NET Sat Feb 15 10:43:10 2003
From: english at KINGSTON.NET (english@KINGSTON.NET)
Date: Tue Aug 10 18:30:14 2004
Subject: Combustion of CO
In-Reply-To: <4.3.1.2.20030213154116.020a4c10@mail.ilstu.edu>
Message-ID: <SAT.15.FEB.2003.104310.0500.>

Hi Paul,

I spent a lot of time trying to sort this out because I had access to the measuring tools,
and I enjoy "perfect world" research.

Carbon monoxide ( CO ) is combustible to generate heat. I believe that a
> stove produces excessive CO when it is burning of charcoal, correct?, or
> when a stove's air supply is reduced, right?

Not always.

There are basic principles which apply and are quite
easy to demonstrate with gas burners.

Example: If you assume perfect mixing, CO decreases as oxygen increases until you
have enough (just enough plus a little). Then CO begins to increase again as excess
oxygen and /or air begins to cool the reaction by remaining as an inert mass that robs
heat.
Oxygen and Temperature are therefore the key, and related variables.

This kind of simplicity is breaks down somewhat in solid fuel burners where gasification
rates are usually variable and mixing is limited and chaotic. In small stoves you can add
quenching effects along the edges, but I think this is minor compared to excess air
quenching.

I once did an experiment using charcoal briquettes. Simply piling them up, as opposed
to spreading them out, reduced CO by half. Putting them into a cylinder, in this case the
Rocket stove/combuster, reduced CO by half again. More piled, more visible flaming,
less CO.

In this example piling reduced excess air and increased temperature. This helped
support a blue CO fuelled "candle" flame.

So lets suppose that these small changes have reduced CO emissions from 100grams
per kg of fuel (as a momentary rate of CO emission) down to 50 , and then to 25.

Now lets put these same briquettes into Tom's Turbo stove with the blower and adjust
the air to an optimum with a turbulent well mixed flame above and no way around it.
Bingo, we are now down to <1gr of CO/kg of charcoal.

The actual temperatures that promote the CO to CO2 reaction are common in the
flickering flames we see, but less common in the spaces around them. So more spaces
result in more CO.

So you can reduce this problem with proper sizeing of the combustion chamber but as
soon as you reduce fire for simmering you have a problem again. Even the Turbo stove
has this problem.

> So, what is required to be able to combust it?
>
> Variables include:
>
> Concentration of CO
CO Flammability limits in my book are for standard temperature and pressure in air.
Air to CO ratios: (lean) 8 to (rich) 1.4

These are not the conditions inside a stove.

>
> Temperature of the CO (including temperature after the O2 in the air is
> introduced.)

Minimum ignition temp. in air is 609 C

> Ignition spark / flame??

> If we have this information, then we can consider how to attain those
> conditions via arrangement of stove components.

The information that stove developers need to assess combustion related design
options start with a real time CO/CO2,O2
monitor, thermocouple array and a time linked voice recorder or note taker.

From tmiles at TRMILES.COM Sat Feb 15 20:17:13 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:14 2004
Subject: Stoves Web Sites Functional
Message-ID: <SAT.15.FEB.2003.171713.0800.TMILES@TRMILES.COM>

The Stoves Discussion Web Sites are all now fully functional at:

http://www.repp.org/discussiongroups/resources/stoves/
http://www.trmiles.com/stoves/ (mirror)

Note: the search utility on both sites will search only documents on the mirror site at www.trmiles.com but the content is identical.

Archives:
http://listserv.repp.org/archives/stoves.html

Tom Miles

From pverhaart at OPTUSNET.COM.AU Sun Feb 16 00:57:53 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:14 2004
Subject: Cooking Brown Rice Test
In-Reply-To: <002b01c2d4ac$f43d0ba0$98387f41@oemcomputer>
Message-ID: <SUN.16.FEB.2003.155753.1000.PVERHAART@OPTUSNET.COM.AU>

At 20:43 14/02/03 -0800, you wrote:
>Dear Stove Friends,
>I did a test to see how my stove actually cooks.
>About 218 grams of wood cooked 8 servings of rice.

We use 700 ml of water for 500 g of white rice. The water plus salt and a
tablespoon of oil is brought to the boil in a pressure cooker. The rice is
put into the boiling water and stirred until the whole mass boils (to
prevent sticking to the bottom and burning). The cooker is closed and
heated on full power until steam escapes. The power is reduced and the
pressure maintained for 5 minutes. All the water is absorbed. I notice that
some recipes prescribe a veritable ocean of water, most of which is
discarded after the rice is cooked.
Yes, I think adding the rice to the boiling water and stirring prevents
burning.

Cheers

Peter Verhaart

From jaakko.saastamoinen at VTT.FI Mon Feb 17 05:13:51 2003
From: jaakko.saastamoinen at VTT.FI (Jaakko Saastamoinen)
Date: Tue Aug 10 18:30:14 2004
Subject: Combustion of CO
Message-ID: <MON.17.FEB.2003.121351.0200.JAAKKO.SAASTAMOINEN@VTT.FI>

At 15:50 13.2.2003 -0600, you wrote:
>Stovers,
>
>Carbon monoxide ( CO ) is combustible to generate heat. I believe that a
>stove produces excessive CO when it is burning of charcoal, correct?, or
>when a stove's air supply is reduced, right?
>
>So, what is required to be able to combust it?
>
>Variables include:
>
>Concentration of CO
>
>Temperature of the CO (including temperature after the O2 in the air is
>introduced.)
>
>Ignition spark / flame??
>
>Other factors??
>
If the air does not contain any water vapour, the rate of oxidation of CO
becomes very slow and emissions of CO may become high.
Water vapour forms radicals that are important even this cannot be seen in
the global reaction CO+1/2 O2 = CO2. Usually there is some water vapour in
the air, but in dry climate, this might have an effect. There is hydrogen
in wood (forming water vapour), and also small amounts in the charcoal.
Burning wood (volatiles containing hyrogen) and charcoal simultaneously
might produce enough necessary radicals to keep CO burning in dry climates.

Jaakko Saastamoinen

>If we have this information, then we can consider how to attain those
>conditions via arrangement of stove components.
>
>Thanks in advance.
>
>Paul
>Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
>Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
>Dept of Geography - Geology (Box 4400), Illinois State University
>Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
>E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>
>

From tmiles at TRMILES.COM Mon Feb 17 10:41:26 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:14 2004
Subject: Report from Guatemala: Masons on a Mission builds estufa #1000
Message-ID: <MON.17.FEB.2003.074126.0800.TMILES@TRMILES.COM>

The following report came in this weekend from Pat Manley, Masons on a Mission http://www.midcoast.com/masonsonamission/

-------------

Hi Tom
Pat Manley here, with Masons on a Mission (MOM).
I just wanted to make a quick report as to our milestone here in Guatemala.
MOM has been building masonry estufas here in the Xela area, along with Tom Clarke and Ali Ross of the Guatemala Stove Project, over the past 4 years, and we have just reached the placement of estufa number 1000!
About 100 of them have been hand built of block and brick by our volunteers from the US and Canada over the past 4 Februarys, about 800 by a crew of Maya masons that we fund, and about another 100 HELPS stoves that we bought, and had installed by a Maya womens group in the Xela area.
All 1000 estufas were built with funds that we have raised in the US and Canada.
Each estufa replaces the filthy open 3 stone fire that were being used in 1000 Maya dwellings. You can?t believe the appreciation shown by the families that have received these estufas.
I know that compared to the work that so many in the world do in the effort to eliminate the 3 stone fires this may not seem such a big deal, but we are proud to have played a part in it anyway, and we look forward to building the next 1000, and the next!
Just wanted to share this with you all. In the world today, every little bit helps.
Su Amigo..Pat

From reecon at MITSUMINET.COM Mon Feb 17 11:24:56 2003
From: reecon at MITSUMINET.COM (reecon)
Date: Tue Aug 10 18:30:14 2004
Subject: Charcoal briquetting unit.
Message-ID: <MON.17.FEB.2003.192456.0300.REECON@MITSUMINET.COM>

Hi all,
We are in the process of establishing a charcoal production and briquetting unit in Kenya. We are looking for a simple charcoal briquetting unit. If any one has a new or second hand one available for sale please get in touch. Give us all the information on production rates and price, if possible FOB Mombasa.

Alternatively we would welcome any ideas on how to fabricate one (DIY) that could be run by a diesel engine.

Regards,
Musungu.

From dstill at EPUD.NET Mon Feb 17 05:50:20 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:14 2004
Subject: Report from Guatemala: Masons on a Mission builds estufa #1000
Message-ID: <MON.17.FEB.2003.025020.0800.DSTILL@EPUD.NET>

Dear Tom,

Please pass this along, when you have time...

Congratulations to Pat, Tom, Ali and Masons on a Mission!

Seems to me that every life is a miracle. A stove assists the small miracles
of normal, daily life to happen a bit easier. Who's to say what miracle will
be the fulcrum and lever that moves the world? One thousand stoves is a
tremendous accomplishment!

All Best,

Dean

From snienhuys at SNV.ORG.NP Tue Feb 18 00:09:04 2003
From: snienhuys at SNV.ORG.NP (Sjoerd Nienhuys)
Date: Tue Aug 10 18:30:14 2004
Subject: Charcoal briquetting unit.
In-Reply-To: <002401c2d6a1$45788440$85436dc1@ras>
Message-ID: <TUE.18.FEB.2003.105404.0545.SNIENHUYS@SNV.ORG.NP>

Dear all,

I made a short report (1MB) on Charcoal briquetting in Nepal,
to whom shall I mail this?

Sjoerd Nienhuys
Senior Renewable Energy Advisor
SNV/N, Netherlands Development Organisation
P.O. Box 1966, Kathmandu, Nepal
Telephone: ++997-1-523444
snienhuys@snv.org.np

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf Of reecon
Sent: Monday, February 17, 2003 10:10 PM
To: STOVES@LISTSERV.REPP.ORG
Subject: [STOVES] Charcoal briquetting unit.

Hi all,
We are in the process of establishing a charcoal production and briquetting
unit in Kenya. We are looking for a simple charcoal briquetting unit. If any
one has a new or second hand one available for sale please get in touch.
Give us all the information on production rates and price, if possible FOB
Mombasa.

Alternatively we would welcome any ideas on how to fabricate one (DIY) that
could be run by a diesel engine.

Regards,
Musungu.

From mittaln at IITB.AC.IN Tue Feb 18 01:35:16 2003
From: mittaln at IITB.AC.IN (NEERAJ MITTAL)
Date: Tue Aug 10 18:30:15 2004
Subject: No subject
Message-ID: <TUE.18.FEB.2003.120516.0530.MITTALN@IITB.AC.IN>

Dear All,

I want to know about continous feed gasifier stoves. Had anybody worked
upon contionus feed stoves?

Please suggest some references from where i can study about these
gasifiers and where I can look up for such stoves.

Neeraj

From crispin at NEWDAWN.SZ Tue Feb 18 02:19:42 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Need for emissions testing equipment in Swaziland
Message-ID: <TUE.18.FEB.2003.091942.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

I would like to find, as soon as possible, some equipment for measuring
indoor air quality and stove emissions. These might be two different
instruments. What do you say?

We at the Renewable Energy Association are going to proceed immediately with
a project to get some baseline info on cooking indoors.

What machine(s) do I need and where can I find them? We have about $1500
budgeted for this.

Regards
Crispin

From stephen.gitonga at UNDP.ORG Tue Feb 18 10:03:48 2003
From: stephen.gitonga at UNDP.ORG (Stephen Gitonga)
Date: Tue Aug 10 18:30:15 2004
Subject: [Fwd: Request for Help]
Message-ID: <TUE.18.FEB.2003.100348.0500.STEPHEN.GITONGA@UNDP.ORG>

This came to me but was meant for the stovers, Just passing it over to
the list.

Stephen Gitonga
-------------- next part --------------
An embedded message was scrubbed...
From: "Darwin Curtis" <darcurtis@worldnet.att.net>
Subject: Request for Help
Date: Sat, 15 Feb 2003 09:50:02 -0500
Size: 2669
Url: http://listserv.repp.org/pipermail/stoves/attachments/20030218/62e9cd0c/nsmailR3.mht
From kchisholm at CA.INTER.NET Tue Feb 18 10:39:12 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:15 2004
Subject: [Fwd: Request for Help]
Message-ID: <TUE.18.FEB.2003.113912.0400.KCHISHOLM@CA.INTER.NET>

Dear Stephen

Could you please open the attachment and send only opened attachments to the
List?

Thanks.

kevin
----- Original Message -----
From: "Stephen Gitonga" <stephen.gitonga@UNDP.ORG>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, February 18, 2003 11:03 AM
Subject: [STOVES] [Fwd: Request for Help]

> This came to me but was meant for the stovers, Just passing it over to
> the list.
>
> Stephen Gitonga

From tmiles at TRMILES.COM Tue Feb 18 11:17:47 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:15 2004
Subject: [Fwd: Request for Help]
Message-ID: <TUE.18.FEB.2003.081747.0800.TMILES@TRMILES.COM>

Stephen,

The list doesn't accept attachments to emails. Please send it to me at
tmiles@trmiles.com

Thanks

Tom Miles
----- Original Message -----
From: "Stephen Gitonga" <stephen.gitonga@UNDP.ORG>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, February 18, 2003 7:03 AM
Subject: [STOVES] [Fwd: Request for Help]

> This came to me but was meant for the stovers, Just passing it over to
> the list.
>
> Stephen Gitonga

From crispin at NEWDAWN.SZ Wed Feb 19 09:22:40 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Latest from New Dawn - Auke
Message-ID: <WED.19.FEB.2003.162240.0200.CRISPIN@NEWDAWN.SZ>

Dear Auke

I am not sure if you are accessing your mail while in the Phillipines, but
look for Rina King from Johannesburg, representing New Dawn Energy Systems.
She is delivering our co-authored paper.

Regards
Crispin

----- Original Message -----
From: <koopmans@LOXINFO.CO.TH>

Auke

Will be in the Philippines as well and hope to learn a lot from your efforts
to make clean and fuel saving stoves.

From psanders at ILSTU.EDU Wed Feb 19 14:15:13 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:15 2004
Subject: Continuous feed gasifiers
In-Reply-To: <1104.10.7.0.57.1045550116.squirrel@pgmail.iitb.ac.in>
Message-ID: <WED.19.FEB.2003.131513.0600.PSANDERS@ILSTU.EDU>

Hello,

If you define "continuous feed gasifier stoves" as being the small stoves
for domestic cooking or small production activities, the answer "there are
none," at least not discussed on the Stoves list serve. The gasifier
stoves by Tom Reed and myself are batch loaded. The Chinese gasifer stoves
are quite unknown at present.

Continuous feed is associated with larger gasifiers, and for that you
should contact the "Gasification" list serve moderated by Tom Reed.

You did not tell us much about why you wanted the information. That
sometimes helps us give better replies.

Regards,

Paul

At 12:05 PM 2/18/03 +0530, NEERAJ MITTAL wrote:
>Dear All,
>
>I want to know about continous feed gasifier stoves. Had anybody worked
>upon contionus feed stoves?
>
>Please suggest some references from where i can study about these
>gasifiers and where I can look up for such stoves.
>
>
>Neeraj

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From tmiles at TRMILES.COM Wed Feb 19 20:27:59 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:15 2004
Subject: Latest from New Dawn - Auke
Message-ID: <WED.19.FEB.2003.172759.0800.TMILES@TRMILES.COM>

Auke, Crispin,

Can you post or point to a programme for the meeting in the Phillipines that list
what papers will be presented?

Thanks

Tom

----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, February 19, 2003 6:22 AM
Subject: Re: [STOVES] Latest from New Dawn - Auke

Dear Auke

I am not sure if you are accessing your mail while in the Phillipines, but
look for Rina King from Johannesburg, representing New Dawn Energy Systems.
She is delivering our co-authored paper.

Regards
Crispin

----- Original Message -----
From: <koopmans@LOXINFO.CO.TH>

Auke

Will be in the Philippines as well and hope to learn a lot from your efforts
to make clean and fuel saving stoves.

From crispin at NEWDAWN.SZ Thu Feb 20 02:23:42 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Latest from New Dawn - Auke
Message-ID: <THU.20.FEB.2003.092342.0200.CRISPIN@NEWDAWN.SZ>

Dear Tom'n'all

Nope.

Crispin

++++++++++++

Auke, Crispin,

Can you post or point to a programme for the meeting in the Phillipines that
list
what papers will be presented?

Thanks

Tom

From koopmans at LOXINFO.CO.TH Thu Feb 20 06:55:44 2003
From: koopmans at LOXINFO.CO.TH (koopmans@LOXINFO.CO.TH)
Date: Tue Aug 10 18:30:15 2004
Subject: Latest from New Dawn - Auke
Message-ID: <THU.20.FEB.2003.185544.0700.>

Tom/Crispin and other stovers,

Have only a hard copy of the programme. Papers are expected to be posted on www.arecop.org sometime soon (probably first week March).

Regards,

Auke

>From: Crispin <crispin@newdawn.sz>
>Date: Thu, 20 Feb 2003 09:23:42 +0200
>Subject: Re: [STOVES] Latest from New Dawn - Auke
>
>
>Dear Tom'n'all
>
>Nope.
>
>Crispin
>
>++++++++++++
>
>Auke, Crispin,
>
>Can you post or point to a programme for the meeting in the Phillipines that
>list
>what papers will be presented?
>
>Thanks
>
>Tom

From tmiles at TRMILES.COM Thu Feb 20 11:50:48 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:15 2004
Subject: PARU stoves
Message-ID: <THU.20.FEB.2003.085048.0800.TMILES@TRMILES.COM>

Neeraj

Auke Koopmans is probably the best source. There's a diagram of the Paru stove on pages 172, 173 of the RWEDP Report No. 56 at http://www.rwedp.org/acrobat/rm56.pdf WOODFUEL PRODUCTION AND MARKETING IN MYANMAR NATIONAL WORKSHOP Forest Department, Yangon 16 - 19 March 1999

Tom Miles

----- Original Message -----
From: "NEERAJ MITTAL" <mittaln@iitb.ac.in>
To: <tmiles@trmiles.com>
Sent: Wednesday, February 19, 2003 11:26 PM
Subject: PARU stoves

> Dear All,
>
>
> Can anyone tell me about PARU stoves in details?
>
> Neeraj
>
>
>

From tmiles at TRMILES.COM Fri Feb 21 02:15:10 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:15 2004
Subject: Fw: [STOVES] Request for Help]
Message-ID: <THU.20.FEB.2003.231510.0800.TMILES@TRMILES.COM>

Stovers:

Please note the request below from Darwin Curtis to the list.

Tom Miles

> From: "Darwin Curtis" <darcurtis@worldnet.att.net>
> Date: Fri, Feb 14, 2003, 16:19
> To: Stovers <STOVES@LISTSERV.REPP.ORG>
> Subject: Request for Advice
>
> Stovers
>
> I need advice from someone among you.
>
> We have a Mexican colleague who is Director General of the Fundo Mexicano
> para la Conservation de la Natura. As such, he is interested in the
> promotion of alternative household energies that might reduce
environmental
> degradation. We are collaborating on solar applications only. He is
> interested in exploring other technologies including fuel efficient
stoves,
> and we have offered to help.
>
> If your activities include outreach as well as R&D, and if Mexico is
> included in your geographic spectrum, do you have someone to whom I could
> refer our Mexican colleague? If not, can you suggest where I might find
> those best equipped to guide him?
>
> Dar Curtis
> Solar Household Energy, Inc.
> (A not-for-profit organization)
> www.she-inc.org

From ronallarson at QWEST.NET Fri Feb 21 15:49:40 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:15 2004
Subject: Fw: [STOVES] Request for Help]
In-Reply-To: <011a01c2d978$fd1acc50$0301a8c0@tomslaptop>
Message-ID: <FRI.21.FEB.2003.134940.0700.RONALLARSON@QWEST.NET>

Darwin:

1. Before answering your question - let me congratulate ou on your web site
and your solar cooking mission. I found the NASA links quite fascinating
and much more extensive than I was aware. I think there must be a part of
the NASA data base that is useful to those interested in biomass stoves -
but didn't find it yet.
The Indian site you linked to
(http://www.rohitassolarcooker.com/Our%20Products.htm) looked like they had
a good product - but no prices. What are the best solar cooker prices you
now find around the world?

2. I tried a Google search with translation (that turned "Foundation" into
"Bottom" ) - as my Spanish is very rudimentary. Our Spanish speakers (and
we have many - but especially Rogerio Miranda who has a Spanish language
site that he can refer you to) may want to go to
http://www.redlac.org/cgi-bin/genpagfanI.pl?accion=1. From this, I conclude
that your contact is Lorenzo Rosenzweig Pasquel . My first recommendation is
that someone speaking English within this organization join "stoves" and
learn more about the many types of improvved stoves that are coming along.
Then pepper us with questions.

3. My guess is that Mexico will have different "best" stoves in different
parts of Mexico. I would do lots of local testing before picking a single
"winner". Look over the web archives that Tom Miles is developing at
http://www.repp.org/discussiongroups/resources/stoves/ - as well as the
archives that can be reached from there or by going directly
to: http://listserv.repp.org/archives/stoves.html. For older archives go to
(at least now) http://www.crest.org/discussion/stoves/200201/

4. best of luck.

Ron

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of Tom Miles
>Sent: Friday, February 21, 2003 12:15 AM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: [STOVES] Fw: [STOVES] Request for Help]
>
>
>Stovers:
>
>Please note the request below from Darwin Curtis to the list.
>
>Tom Miles
>
>> From: "Darwin Curtis" <darcurtis@worldnet.att.net>
>> Date: Fri, Feb 14, 2003, 16:19
>> To: Stovers <STOVES@LISTSERV.REPP.ORG>
>> Subject: Request for Advice
>>
>> Stovers
>>
>> I need advice from someone among you.
>>
>> We have a Mexican colleague who is Director General of the Fundo Mexicano
>> para la Conservation de la Natura. As such, he is interested in the
>> promotion of alternative household energies that might reduce
>environmental
>> degradation. We are collaborating on solar applications only. He is
>> interested in exploring other technologies including fuel efficient
>stoves,
>> and we have offered to help.
>>
>> If your activities include outreach as well as R&D, and if Mexico is
>> included in your geographic spectrum, do you have someone to whom I could
>> refer our Mexican colleague? If not, can you suggest where I might find
>> those best equipped to guide him?
>>
>> Dar Curtis
>> Solar Household Energy, Inc.
>> (A not-for-profit organization)
>> www.she-inc.org
>
>

From snkm at BTL.NET Sat Feb 22 14:44:56 2003
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:15 2004
Subject: [BiomassGroup] Bush's H-Car Is Just Hot Air
Message-ID: <SAT.22.FEB.2003.134456.0600.SNKM@BTL.NET>

At 12:16 PM 2/22/2003 -0500, Steve Spence wrote:
>
>From: "Robert Cohen" <robtcohen@aol.com.spam.no>
>Subject: Easterbrook: "Bush's H-Car Is Just Hot Air"
>Date: Friday, February 21, 2003 6:30 PM
>
>http://www.tnr.com
>
>http://www.thenewrepublic.com
>
>copyrighted by The New Republic, article is published in issue of 24 Feb 03
>
>WHY BUSH'S H-CAR IS JUST HOT AIR.
>

Dear all --

The solution to this present problem was clearly specified on the Gas List
a few years back.

Increase the cost of gasoline to $5.00 US per gallon (as indeed they have
done in Europe)

Say $1.00 is the true price -- the rest is "tax" -- and that money can be
then used in productive manner to re-adjust the entire energy problem.

That stops the problem in it's tracks cold!

Further -- offer heavy tax rebates to all viable alternative fuels.

So -- as a example -- ethanol could be used to replace gasoline -- at a
full price to the suppliers of $2.50 US per gallon

Why $2.50 and not the full five dollars??

Because you can get only have the miles from a gallon of ethanol as you can
from a gallon of gasoline.

But still -- at $2.50 it would pay people to get into it!

We also know of many projects to make bio fuels from biomass that would
develop rapidly into full scale production if they were assured a full
"BTU" adjusted pricing. RIn most of those cases -- better than $2.50 per
gallon -- but never the full $5.00 per gallon.

But such a real solution can never happen -- because it literally would
destroy all the major oil corps -- and for America -- only one thing counts
anymore -- the Corporate Bottom line -- profit for the share holders.

So why even think about any of this -- it's a done deal -- this turn of the
wheel is over -- maybe in the next society that raises up from these ashes
-- say 10,000 years down the road -- they will have evolved a better system
of energy production and distribution.

But I'm not betting on that either!!

It appears there is one thing that does truly never changes -- and that is
human nature!

I am setting up a micro power plant here in Belize that will be a diesel
operating in dual fuel mode -- strong rum made from sugar cane -- 95% --
plant oil (cohune nut oil) 5% --

I am investigating making Plante Style lead acid storage batteries by
recycling (lead refining) scrap car batteries. And going electric
"traction" -- all the way!

My lights here never get dim -- but I can't promise anything for yours --

Prepare for the worse -- the good looks after itself.

You can see some of the equipment i already have in place at:

http://turneffecoconut.com/

The cane crusher and two more old style listers should be arriving from
India next week -- finally!!

Both sources of "fuel" are also independent business operations and will
turn a profit in their respective products -- high quality food oils --
potable rum and "panala" (whole, natural, sugar -- just like the old maple
sugar -- and made the same way -- in a 'pan')

"Power" is the by-product.

Growing your own is the only real solution.

Dreaming is so big these days -- real activity is history!

Have a good war event --

till then -- hope you all sleep well --

Peter Singfield

Xaibe -- Belize

From yark at U.WASHINGTON.EDU Mon Feb 24 02:11:49 2003
From: yark at U.WASHINGTON.EDU (Tami Bond)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
In-Reply-To: <007e01c2cd65$d5b84710$418992cb@aukeufr0ppg2sw>
Message-ID: <SUN.23.FEB.2003.231149.0800.YARK@U.WASHINGTON.EDU>

Dear Stovers,

My, we are quiet! Let me throw a couple of stones down the well and see if
there's any response.

Alex English recently brought up the 'cliff' aspect of combustion:
transition from poor to good. This is standard combustion behavior that
occurs because a flame is basically a runaway reaction. You need a certain
amount of stuff to maintain a flame: fuel, and what's called 'free
radicals'-- no, this is not a political debate ;-) Free rads are very
reactive molecules that get the reaction going by nibbling apart more
stable molecules. In burning wood, higher temperature makes both more fuel
(by letting the volatile matter escape) and more free rads. If these
things start reacting, they release energy, and that makes the temperature
higher, which makes more fuel+rads, which makes more flame, which raises
the temperature... and boom, there you go. (Of course, you need oxygen
too. I'm assuming that's not in short supply, although it could be.)
Likewise, if the temperature drops enough, you could lose the ability to
burn up the volatile matter that's being ejected from the wood, and
suddenly your fire starts smoking. Along with 'capturing heat' in the pot,
we need to keep some of it in the fire to keep the reaction going.

We have talked about combustion chambers and fuels. I haven't heard much
about fuel in the combustion chamber. This seems pretty important too.
Two sticks next to each other keep the heat in the fire by radiating heat
to each other. That heat would normally be lost to the walls of the
combustion chamber. If the chamber is insulated, great, but... the best
place for the heat is IN THE FIRE until it's carried up to the pot! Two
sticks that are too close to each other prevent oxygen from getting in,
and that makes a bad burn. There is some optimal distance between sticks.

The position of fuel in the combustion chamber seems very important in
terms of emissions. However, this is one thing we can't regulate on the
user side. The Rocket chamber has an advantage over the three-stone fire
in that it encourages placement of sticks next to each other, but it still
carries smoke over the fire where it can be consumed. The Rocket doesn't
have any requirements for ideal stick distance, though. It's hard to get
the users to load with little sticks instead of big ones-- much less
install them in our 'ideal world' fashion.

Comments?

Tami

From yark at U.WASHINGTON.EDU Mon Feb 24 02:15:57 2003
From: yark at U.WASHINGTON.EDU (Tami Bond)
Date: Tue Aug 10 18:30:15 2004
Subject: web page
Message-ID: <SUN.23.FEB.2003.231557.0800.YARK@U.WASHINGTON.EDU>

By the way, I have put up a small web page for stoves. It doesn't do much
besides referring back to Tom Miles' web site, but it does have links to
pdf files of my ETHOS presentations:

last year - Rocket stove testing and Emission testing recommendations
this year - Emission testing recommendations, short

http://faculty.washington.edu/~yark/stoves.html

Tami

From ronallarson at QWEST.NET Mon Feb 24 11:00:08 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
In-Reply-To: <Pine.A41.4.44.0302232105050.152254-100000@homer09.u.washington.edu>
Message-ID: <MON.24.FEB.2003.090008.0700.RONALLARSON@QWEST.NET>

Tami:

1. I would llike to check whether I am missing some message, because I
don't believe i received the message from Alex - could you send it?

2. You asked "Comments?" - so here are a few:

a. In my charcoal-making stove work, I also found stick placement very
important. Much better if placed vertically - and needed to be jammed
pretty tight. Almost not possible to do pyrolysis well with sawn lumber -
which could act like bigger pieces with the planar surfaces touching not
being good. It seemed like there needed to be a minimum number of pieces in
a "burn" - maybe 20? Therefore for very small units (of type built and
described by Dick Boyt), you needed very small pieces of wood - really
twigs. But the important point here is that this was pyrolysis - not
combustion - which took place above the fuel supply.

b. I am greatly intrigued by your description of the free rads. Could you
give us some references on this topic - which I don't recall ever seeing on
this list or others? What difference would this make in a pyrolysis only
area (CO being produced rather than CO2)?

c. You have not mentioned pre-heating of the air supply (either primary or
secondary) - a point raised several times by Crispin - but not well enough
argued out on this list. Do you care to guess on its importance in simple
cook stoves?

d. It would also seem that refelctive walls would be much superior to
absorbing walls - but also we haven't had that dialog here. Of course if
well insulated, we can absorb and have re-radiation badck in - but I think
the reflective situation would always provide more heat back into the flame.

Thanks for your several thrown "stones".

Ron

 

 

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of Tami Bond
>Sent: Monday, February 24, 2003 12:12 AM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: [STOVES] Combustion
>
>
>Dear Stovers,
>
>My, we are quiet! Let me throw a couple of stones down the well and see if
>there's any response.
>
>Alex English recently brought up the 'cliff' aspect of combustion:
>transition from poor to good. This is standard combustion behavior that
>occurs because a flame is basically a runaway reaction. You need a certain
>amount of stuff to maintain a flame: fuel, and what's called 'free
>radicals'-- no, this is not a political debate ;-) Free rads are very
>reactive molecules that get the reaction going by nibbling apart more
>stable molecules. In burning wood, higher temperature makes both more fuel
>(by letting the volatile matter escape) and more free rads. If these
>things start reacting, they release energy, and that makes the temperature
>higher, which makes more fuel+rads, which makes more flame, which raises
>the temperature... and boom, there you go. (Of course, you need oxygen
>too. I'm assuming that's not in short supply, although it could be.)
>Likewise, if the temperature drops enough, you could lose the ability to
>burn up the volatile matter that's being ejected from the wood, and
>suddenly your fire starts smoking. Along with 'capturing heat' in the pot,
>we need to keep some of it in the fire to keep the reaction going.
>
>We have talked about combustion chambers and fuels. I haven't heard much
>about fuel in the combustion chamber. This seems pretty important too.
>Two sticks next to each other keep the heat in the fire by radiating heat
>to each other. That heat would normally be lost to the walls of the
>combustion chamber. If the chamber is insulated, great, but... the best
>place for the heat is IN THE FIRE until it's carried up to the pot! Two
>sticks that are too close to each other prevent oxygen from getting in,
>and that makes a bad burn. There is some optimal distance between sticks.
>
>The position of fuel in the combustion chamber seems very important in
>terms of emissions. However, this is one thing we can't regulate on the
>user side. The Rocket chamber has an advantage over the three-stone fire
>in that it encourages placement of sticks next to each other, but it still
>carries smoke over the fire where it can be consumed. The Rocket doesn't
>have any requirements for ideal stick distance, though. It's hard to get
>the users to load with little sticks instead of big ones-- much less
>install them in our 'ideal world' fashion.
>
>Comments?
>
>Tami
>
>

From psanders at ILSTU.EDU Mon Feb 24 17:49:24 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:15 2004
Subject: Re-defining What is a stove?
Message-ID: <MON.24.FEB.2003.164924.0600.PSANDERS@ILSTU.EDU>

Stovers,

Because our "definitions of stoves" are so diverse, I would like to refine
my earlier (last month?) message about the 4 critical aspects of
stoves. The four are VERY interrelated, but IMHO it helps to express the
four aspects separately.

1. Source of (heat) energy -- was called fuels -- ultimate source is
sun and uranium, but we are really referring to what is commonly called a
"fuel". Note, electricity, (originating from hydro or wind or fossil fuel
or other more basic energy sources) is also delivered to some homes as a
"fuel," as are wood pieces and cow dung and other biomass, and
coal/oil. Most stoves are specific to a single "fuel" or fuel type, but
some are more flexible in their energy sources. Here we do not really use
the term "efficiency" of an energy source, but we do refer to the energy
value of each type of fuel, some per kilogram, others per liter, others per
..... We need clarity whenever we compare between fuels.

2. Energy (heat) generation unit -- was called the combustion chamber,
but that old name caused questions about the peripheral aspects (fans and
insulation, etc) that are key components to some heat generation
units. (Other energy, such as mechanical force generated by internal
combustion engines, is related, but is not of much interest to our stoves
group that focuses on cooking and some on room heating.) An electric
hot-plate is a heat generation unit, as is a Rocket "unit" or my Juntos
gasifier "unit". Different technologies trying to do the same task, which
is to generate heat. "Efficiency" here refers to conversion of the "fuel"
into heat energy that is delivered to the operational outlet of the heat
generation unit. Smoke is lost energy, so we try to avoid a "poor
burn". Heat radiated from the sides of the generation unit can be
considered lost in most cases, but if it is valued as an addition to room
heat, then the laterally radiated heat can be given a value as part of the
total efficiency. We need clarity whenever we compare different heat
generation units.

3. Energy (heat) capture unit -- was called stove structure (too
vague). Energy capture covers the stove aspects "that deliver the heat
into the pot or plancha" etc. "Efficiency" here refers to whatever it
takes, including supportive legs to capture the heat for useful
purposes. We need clarity whenever we make statements about the heat
capture units.

4. User-practices (the "Human-factor") impacting energy (heat)
utilization --- was called cooking practices. This refers to how
different people and different cultures would make use of the above 3
"aspects" of the "stove." If the cook does not like or will not use a
"stove" because of issues of fuel, or combustion, or types of pots, then
the "stove" is not viable in that situation. And we need clarity and at
least continual recognition about user-practices of heat utilization.

ALL four are ESSENTIAL considerations about heat in "stoves":

source (of heat)
generation (of heat)
capture-for-use (of heat)
user-practices (of heat) (the "Human-factor")

I have written about this because the "Tower of Babel" of stoves
discussions and stove comparisons is daunting, with frequent cross-overs
between these four vastly different aspects of "stoves," even without
mentioning the monetary aspects of each of the four.

Note to Dean Still: At our coming June workshop at Aprovecho, we can have
activities and discussions that relate to each of the 4 aspects, but I
suspect that our "common ground" of interest is in the "generation of heat"
and how the Rocket and the Juntos and other heat-generation-units function
and can assist each other.

And I will attempt to clearly identify these 4 aspects in the meetings in
South Africa on 10 to 14 March. Peter S., Crispin P-P., John D., myself,
and others on the Stoves List Serve will be there.

Love them stoves!!!!!!!

Paul

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From crispin at NEWDAWN.SZ Tue Feb 25 03:46:19 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <TUE.25.FEB.2003.104619.0200.CRISPIN@NEWDAWN.SZ>

Dear Ron and Tami

I read the post from Tami with great interest. I am always looking for
facts that confirm my prejudices and pre-conceived notions about what to
build and burn!

>RWL b. I am greatly intrigued by your description of the free rads.
>Could you give us some references on this topic.

This business makes sense to me as does the chaotic reactions part. I think
the 'mixing' we refer to is to compensate for the utterly unpredictable
nature of the chain reactions taking place. Good mixing refers to making it
happen continuously and completely. To that end I am thinking about ways to
get the injected and drafted-in air to do more spinning. I have also been
thinking about the role played by the fallen embers in the Tsotso, Rocket
and Vesto as primary air pre-heaters. I wonder if there is a pick up of
free radicals in that process?

>RWL c. You have not mentioned pre-heating of the air supply (either
>primary or secondary) - a point raised several times by Crispin - but
>not well enough argued out on this list. Do you care to guess on its
>importance in simple cook stoves?

I feel that the answer to the question, alone, if well answered and
understood and then applied in the field, could have the same effect as
tripling the woodfuel resources of the planet. The savings are profound and
there is probably nothing else we could do that would have as much benefit.

>RWL d. It would also seem that [reflective] walls would be much
>superior to absorbing walls - but also we haven't had that dialog here.

I have found that maintaining a reflective surface near the fire is nearly
hopeless. It is why a brand new shiny stove givers better performance
figures than one with some hours on it. Reflective is better than
re-radiative but is a bit academic until someone comes up with a material
that remains reflective after hours at 700 C. Perhaps a reflective ceramic
glaze on a thin clay chamber?

>TB In burning wood, higher temperature makes both more fuel
>(by letting the volatile matter escape) and more free rads. If these
>things start reacting, they release energy, and that makes the temperature
>higher, which makes more fuel+rads, which makes more flame, which raises
>the temperature...

Preheating the primary are really helps this happen. It is somewhat
disappointing to see the clay stoves all over the internet have basically no
preheating at all. This is a serious and persistent deficiency. It is as
if the metal stove people and the clay stove people live in different
worlds. The clay stoves seem to be 'sheltered fires' more than 'stoves'.
People build a massive clay stove then make the heat pick-up very effective
and then bleat about the 'improvement' made, while I only see the smoke that
continues to pour out of the chimney as unnecessarily wasted fuel cause by a
failure to apply well known combustion principles. I am discussing this
with ILRI in Ethiopia to see if something can be done to combine the metal
stove knowledge with the clay stove producers.

I find a major advantage to preheating the air is that a very small fire can
be maintained for a long time. Also, it is easier to burn the 'charcoal' in
a Shise/Vesto which as Vivienne's testing in Northern Prov if South Africa
(GTZ, November) showed, is something like 20% of that left by a regular
fire. It is easiest to get high heat transfer numbers when simmering over a
very small fire: low chimney velocities, major preheating, relatively low
inside-the-grate temperatures=low losses.

Just so you know, there is a guy called Chris Kok in Harare
dozi@africaonline.co.zw who is making a hydraulically compressed
sawdust+binder 'puck' (90 dia 35 thick) which he has burned over the weekend
in a Shisa stove he borrowed from GTZ-ProBEC. It weighs about 185 gm and
burns for 90 minutes - one unit on its own. This is not a useful amount of
heat but it shows that preheating the air can maintain a tiny, efficient
fire for a long time. He needs to load about 6 pucks into the grate to give
a useful heat, I think. Chris seems to be intersted in selling the
briquettes and the technology for making them. That density is quite good
and does not involve a massive extruder.

>TB I haven't heard much about fuel in the combustion chamber.
>This seems pretty important too. Two sticks next to each other
>keep the heat in the fire by radiating heat to each other.

I feel that heating the incoming air is a way to ameliorate the need for
close-coupled sticks. Reflective walls and hot air are easier to achieve
that exact spacing of a fuel being consumed.

On another note we haven't said much about the pots as promoters of good
cooking. Is that a "bridge too far"?

Rgards to all.
Crispin

From Carefreeland at AOL.COM Tue Feb 25 06:22:40 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <TUE.25.FEB.2003.062240.EST.>

In a message dated 2/24/03 2:15:19 AM Eastern Standard Time,
yark@U.WASHINGTON.EDU writes:

.> Dan's comments
>
> Dear Stovers,
>
> My, we are quiet! Let me throw a couple of stones down the well and see if
> there's any response.
>
> Alex English recently brought up the 'cliff' aspect of combustion:
> transition from poor to good. This is standard combustion behavior that
> occurs because a flame is basically a runaway reaction. You need a certain
> amount of stuff to maintain a flame: fuel, and what's called 'free
> radicals'-- no, this is not a political debate ;-) Free rads are very
> reactive molecules that get the reaction going by nibbling apart more
> stable molecules. In burning wood, higher temperature makes both more fuel
> (by letting the volatile matter escape) and more free rads. If these
> things start reacting, they release energy, and that makes the temperature
> higher, which makes more fuel+rads, which makes more flame, which raises
> the temperature... and boom, there you go. (Of course, you need oxygen
> too. I'm assuming that's not in short supply, although it could be.)
> Likewise, if the temperature drops enough, you could lose the ability to
> burn up the volatile matter that's being ejected from the wood, and
> suddenly your fire starts smoking. Along with 'capturing heat' in the pot,
> we need to keep some of it in the fire to keep the reaction going.

> This is an excellent explaination of what we stovers have all witnessed yet
couldn't put our finger on to describe. A good fire is one with a balance,
in which enough energy is contained to maintain clean combustion, yet not so
much as to cause run away, out of balance, combustion.

>
> We have talked about combustion chambers and fuels. I haven't heard much
> about fuel in the combustion chamber. This seems pretty important too.
> Two sticks next to each other keep the heat in the fire by radiating heat
> to each other. That heat would normally be lost to the walls of the
> combustion chamber. If the chamber is insulated, great, but... the best
> place for the heat is IN THE FIRE until it's carried up to the pot! Two
> sticks that are too close to each other prevent oxygen from getting in,
> and that makes a bad burn. There is some optimal distance between sticks.

> Let me suggest that it is the distance between the sticks, realitive to the
temperature maintained there, and air flow velocity, that causes this balance
or lack thereof. The distance allows a certain velocity of airflow,
maintaining a balance of both retention of heat, and presentation of oxygen
to the combusting gasses.

>
> The position of fuel in the combustion chamber seems very important in
> terms of emissions. However, this is one thing we can't regulate on the
> user side. The Rocket chamber has an advantage over the three-stone fire
> in that it encourages placement of sticks next to each other, but it still
> carries smoke over the fire where it can be consumed. The Rocket doesn't
> have any requirements for ideal stick distance, though. It's hard to get
> the users to load with little sticks instead of big ones-- much less
> install them in our 'ideal world' fashion.

> Let me suggest that the spaces between sticks are not always the most
important factor when a good combustion chamber design is at work. Sometimes
a good combustion chamber can literally "cook" the biomass, even in a pile.
This enables the gas to burned at another location provided enough heat
retention by another means.
> High mass, and heavily insulated low mass stoves, use the walls of the
chamber to maintain combustion temperatures. Often this occurs above the
venting biomass. Infrared radiation from the combustion, is absorbed by the
walls of the chamber and reradiate back into the "smoke" causing combustion
as oxygen levels reach optimum.

>
> Comments?
>
> Tami
>

From Carefreeland at AOL.COM Tue Feb 25 06:38:53 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:15 2004
Subject: Simple Camp Stove Mod #6
Message-ID: <TUE.25.FEB.2003.063853.EST.>

In a message dated 2/8/03 7:30:20 PM Eastern Standard Time, lanny@ROMAN.NET
writes:

>
> http://www.lanny.us/cs6.html
> aprox 200K
>
> Dear stove friends,
> I have a new stove. Simple Camp Stove #6. It is similar to #4 except it has
> a new burner deign that creates a circular fame path.
> http://www.lanny.us/cs6e.jpg 26K.
> I like this stove! It flows better than #4 and handles a larger fire
> without
> smoking. One problem though is that I forgot to wrap the pot convection
> sleeve with insulation, so more heat is escaping through the sleeve and out
> the stove body than #4. I will correct that with #6b. One thing that I like
> about this basic stove design is that is easy and quick to build.
> I will post cooking and efficiency test soon on page two.
> Lanny
>
> Lanny, this is an excellent basic design. I have been reading about a
waste oil burner recently developed that uses some of the same principals of
swirl combustion called the "turks burner".
>Sorry it took so long to reply, but I have been swirling around in more than
a few snowstorms lately.
>You are on the right track by insulating the burner for heat retention. I
am concerned that with insulation the resulting increase in temp may promote
burn through. You may consider using some of the insulating refractory
coatings previously discussed. They would only be needed on the hottest
components. Otherwise try to find some heavier gauge metal or best would be
thin cast iron plate.
> Keep up the excellent engineering. Appears to have fantastic potential for
low emissions. Need to get that tested when primary design phase is complete.

Your companion in combustion,
Dan Dimiduk

From lanny at ROMAN.NET Tue Feb 25 10:10:52 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <TUE.25.FEB.2003.071052.0800.LANNY@ROMAN.NET>

Stove Friends,
See my blather below.
Lanny Henson
----- Original Message -----
From: Ron Larson <ronallarson@QWEST.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, February 24, 2003 8:00 AM
Subject: Re: [STOVES] Combustion

> Tami:
>
> 1. I would llike to check whether I am missing some message,
because I
> don't believe i received the message from Alex - could you send it?
>
> 2. You asked "Comments?" - so here are a few:
>
> a. In my charcoal-making stove work, I also found stick placement
very
> important. Much better if placed vertically - and needed to be jammed
> pretty tight. Almost not possible to do pyrolysis well with sawn lumber -
> which could act like bigger pieces with the planar surfaces touching not
> being good. It seemed like there needed to be a minimum number of pieces
in
> a "burn" - maybe 20? Therefore for very small units (of type built and
> described by Dick Boyt), you needed very small pieces of wood - really
> twigs. But the important point here is that this was pyrolysis - not
> combustion - which took place above the fuel supply.

LH- One of the problems that I have run into with stick placement is that
sticks are not just sticks.
Sticks vary in, diameter, length, shape, moisture, resin content, density,
dead wood, new green wood, split wood or whole sticks, sticks that are flat
with no air space between, with air space, grass tied in knots and I am sure
more.
So it would be practical for a stove have some flexibility in the type of
fuel that it will burn.
I know that I have been a little guilty of burning the fuel that works best
for my design and neglecting other fuels.

> b. I am greatly intrigued by your description of the free rads.
Could you
> give us some references on this topic - which I don't recall ever seeing
on
> this list or others? What difference would this make in a pyrolysis only
> area (CO being produced rather than CO2)?
>
> c. You have not mentioned pre-heating of the air supply (either
primary or
> secondary) - a point raised several times by Crispin - but not well enough
> argued out on this list. Do you care to guess on its importance in simple
> cook stoves?

LH- It seems like to me that a more important factor than preheating is the
focus (direction, shape, velocity) of the supply air.

Lanny Henson

> d. It would also seem that refelctive walls would be much
superior to
> absorbing walls - but also we haven't had that dialog here. Of course if
> well insulated, we can absorb and have re-radiation badck in - but I think
> the reflective situation would always provide more heat back into the
flame.
>
> Thanks for your several thrown "stones".
>
> Ron

From crispin at NEWDAWN.SZ Tue Feb 25 07:09:37 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <TUE.25.FEB.2003.140937.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

DAN wrote
> > Let me suggest that the spaces between sticks are not always the most
>important factor when a good combustion chamber design is at work.
Sometimes
>a good combustion chamber can literally "cook" the biomass, even in a pile.
>This enables the gas to burned at another location provided enough heat
>retention by another means.
> > High mass, and heavily insulated low mass stoves, use the walls of the
>chamber to maintain combustion temperatures. Often this occurs above the
>venting biomass. Infrared radiation from the combustion, is absorbed by
the
>walls of the chamber and reradiate back into the "smoke" causing combustion
>as oxygen levels reach optimum.

My take on this is a little different: the heat radiating to the sides can
be conducted away into incoming secondary air, and that air fed into the
smoke above the main fire providing more (usually needed) oxygen for
complete combustion. In a great many cases, if there 'was' excess oxygen
available in the smokey air, it was used up releasing more smoke during
pirmary combustion. It is smoking because there is not enough air.

When the fire is choked a bit (which is a frequent condition), you are
better off introducing preheated secondary air than you are retaining heat
with insulation and trying to get CO to burn to CO2 without enough oxygen in
the air. You could have perfect insulation, perfect reflection and 100%
conversion of available oxygen and still have a smokey stove due to excess
gassification of the wood and inadequate, hot secondary air.

As Dan points out, raising the temperature of the combustion chamber reduces
life, and I say, does not do much to provide more air.

Regards
Crispin

From Carefreeland at AOL.COM Tue Feb 25 07:17:54 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <TUE.25.FEB.2003.071754.EST.>

In a message dated 2/24/03 11:01:10 AM Eastern Standard Time,
ronallarson@QWEST.NET writes:

> Daniel's comments
>
> Tami:
>
> 1. I would llike to check whether I am missing some message,
> because I
> don't believe i received the message from Alex - could you send it?
>
> 2. You asked "Comments?" - so here are a few:
>
> a. In my charcoal-making stove work, I also found stick placement
> very
> important. Much better if placed vertically - and needed to be jammed
> pretty tight. Almost not possible to do pyrolysis well with sawn lumber -
> which could act like bigger pieces with the planar surfaces touching not
> being good. It seemed like there needed to be a minimum number of pieces
> in
> a "burn" - maybe 20? Therefore for very small units (of type built and
> described by Dick Boyt), you needed very small pieces of wood - really
> twigs. But the important point here is that this was pyrolysis - not
> combustion - which took place above the fuel supply.

> Ron, I think there is a couple of reasons for the vertical placement of
the sticks working better. The first is that the vertical sticks pyrolised
downward more continuously like a candle wick burning. The separation of
other configurations could interrupt the smooth "flow of the glow." The
other reason I could think of, would be the chimney effect that rising
combustion air and gasses would have between the sticks. There may be other
reasons I missed.

>
> b. I am greatly intrigued by your description of the free rads.
> Could you
> give us some references on this topic - which I don't recall ever seeing on
> this list or others? What difference would this make in a pyrolysis only
> area (CO being produced rather than CO2)?
>
> c. You have not mentioned pre-heating of the air supply (either
> primary or
> secondary) - a point raised several times by Crispin - but not well enough
> argued out on this list. Do you care to guess on its importance in simple
> cook stoves?

> As you well know some of my early letters to stoves, promoted the virtues
of preheating in small stoves. I believe that Crispin took some of what I
stated to heart. That is why he is having success at combustion turn down.
> One of the biggest problems with small stoves is the rapid cooling
of combustion gasses below the clean combustion temperature. By starting
with adequately heated combustion air, the problem of cool air quenching some
of the combustion is eliminated. This leaves only the cold combustion
chamber walls to do the quenching.
>As Tom Reed stated so well, you must take into consideration the expansion
of the air and the need for more airspace to accommodate it. This requires
the use of controls on any preheated air to compensate for temperature
changes.
> It must be also pointed out, that the preheated air can also produce hotter
exhaust gas with greater vertical escape velocity. This can compensate for
the thinner air by accelerating draft to a point. This would be more notable
on large chimney stoves.

> d. It would also seem that refelctive walls would be much superior to
> absorbing walls - but also we haven't had that dialog here. Of course if
> well insulated, we can absorb and have re-radiation badck in - but I think
> the reflective situation would always provide more heat back into the
> flame.
>
> This is a serious point of study. I for one, favor the re-radiation
technique. I think the chances of keeping a clean shiny surface in a
combustion chamber are slim to none. Re-radiation is how the three stone
fire works, and how nature keeps large fires burning clean. If a combustion
chamber were to be super reflective, it would not even get hot to begin with.

> Don't forget that infrared passes through many clear gasses. This
suggests that actual contact between the gasses and the hot surfaces may be
more important to heat transmission. This favors turbulence as the heating
technique.
> The insulation is most important to efficiently reach combustion chamber
temperatures that favor rapid re-radiation. The high mass stoves do this
through slow thermal conductivity allowing a hot interior surface. They just
take more time to do this. No heat is lost, it just takes longer to be
emitted. For a heating stove this is desirable. Not for a cooking stove in
the tropics.

> Thanks for your several thrown "stones".
>
> Ron
>
>
> > I Just bounced a few back. Open to comments

Daniel Dimiduk

From dstill at EPUD.NET Wed Feb 19 07:20:13 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <WED.19.FEB.2003.042013.0800.DSTILL@EPUD.NET>

-----Original Message-----
From: Ron Larson

Dear Ron: Thanks for thrown stones. As far as preheating primary and
secondary air goes I have a couple of comments. 1.) the heat source for
preheating air is the combustion chamber. Taking heat from the combustion
chamber isn't positive because we want highest temperatures there to achieve
clean burning. 2.) The air in the 12" Rocket insulated cylinder above the
combustion chamber exits at around 1850 F . Most of the air below this
point, above the fire, is as hot or hotter. 3.) We know from tests that more
oxygen is not needed in the cylinder. Therefore, preheating secondary air
has been seen as moot.

But, everyone here would love to preheat primary air, trying to increase
combustion temperatures. I don't know how to easily do this, except for
lengthening the fuel magazine, in a sidefeed arrangement. Twin fires, as in
a hill climbing Japanese kiln, in side by side fuel magazines, are too
complicated!

I'm building a blast furnace heating stove now that preheats primary air
using a fan and closed door into the combustion chamber. Blasts of air,
mixing air, fuel, flame, plus temperatures well above 2,000F do wonders for
clean combustion. But, of course, we have to use refractory cement instead
of steel for the stove body, which would melt.

All Best,

Dean
>
> c. You have not mentioned pre-heating of the air supply (either
primary or
>secondary) - a point raised several times by Crispin - but not well enough
>argued out on this list. Do you care to guess on its importance in simple
>cook stoves?
>

>
>Ron
>
>
>
>
>
>>-----Original Message-----
>>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>>Behalf Of Tami Bond
>>Sent: Monday, February 24, 2003 12:12 AM
>>To: STOVES@LISTSERV.REPP.ORG
>>Subject: [STOVES] Combustion
>>
>>
>>Dear Stovers,
>>
>>My, we are quiet! Let me throw a couple of stones down the well and see if
>>there's any response.
>>
>>Alex English recently brought up the 'cliff' aspect of combustion:
>>transition from poor to good. This is standard combustion behavior that
>>occurs because a flame is basically a runaway reaction. You need a certain
>>amount of stuff to maintain a flame: fuel, and what's called 'free
>>radicals'-- no, this is not a political debate ;-) Free rads are very
>>reactive molecules that get the reaction going by nibbling apart more
>>stable molecules. In burning wood, higher temperature makes both more fuel
>>(by letting the volatile matter escape) and more free rads. If these
>>things start reacting, they release energy, and that makes the temperature
>>higher, which makes more fuel+rads, which makes more flame, which raises
>>the temperature... and boom, there you go. (Of course, you need oxygen
>>too. I'm assuming that's not in short supply, although it could be.)
>>Likewise, if the temperature drops enough, you could lose the ability to
>>burn up the volatile matter that's being ejected from the wood, and
>>suddenly your fire starts smoking. Along with 'capturing heat' in the pot,
>>we need to keep some of it in the fire to keep the reaction going.
>>
>>We have talked about combustion chambers and fuels. I haven't heard much
>>about fuel in the combustion chamber. This seems pretty important too.
>>Two sticks next to each other keep the heat in the fire by radiating heat
>>to each other. That heat would normally be lost to the walls of the
>>combustion chamber. If the chamber is insulated, great, but... the best
>>place for the heat is IN THE FIRE until it's carried up to the pot! Two
>>sticks that are too close to each other prevent oxygen from getting in,
>>and that makes a bad burn. There is some optimal distance between sticks.
>>
>>The position of fuel in the combustion chamber seems very important in
>>terms of emissions. However, this is one thing we can't regulate on the
>>user side. The Rocket chamber has an advantage over the three-stone fire
>>in that it encourages placement of sticks next to each other, but it still
>>carries smoke over the fire where it can be consumed. The Rocket doesn't
>>have any requirements for ideal stick distance, though. It's hard to get
>>the users to load with little sticks instead of big ones-- much less
>>install them in our 'ideal world' fashion.
>>
>>Comments?
>>
>>Tami
>>
>>
>

From crispin at NEWDAWN.SZ Tue Feb 25 16:07:39 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <TUE.25.FEB.2003.230739.0200.CRISPIN@NEWDAWN.SZ>

Dear Dean

You wrote:
>1.) the heat source for preheating air is
>the combustion chamber. Taking heat from
>the combustion chamber isn't positive
>because we want highest temperatures
>there to achieve clean burning.

After the heat reaches the incoming air (by whatever means you build) there
is no net loss of heat if it is piped back into the fire. The math on this
is simple. In a thin steel stove, the time to achieve this condition is
measured in seconds. It would not be correct to say that heat is 'lost' by
preheating the incoming air unless some is radiated away from the stove
altogether and not picked up.

Once the fire is stabilized, the net loss is about zero and the resulting
flame temperature is higher (like 200 C), especially at the initial stages
or primary combustion. You can easily check this with a thermocouple. The
secondary temps are also higher, even though heat is heading out again in
that area. The steel lasts longer and you have better combustion with a
wider range of fuels.

>3.) We know from tests that more oxygen is not
>needed in the cylinder. Therefore, preheating
>secondary air has been seen as moot.

I agree with this as long as two criteria are met: 1) that you indeed have
sufficient air incoming for the fuel load, and 2) that you never turn the
fire down by choking it.

If the fire gets larger because more fuel is present, then at some point it
definitely runs out of oxygen for any given dimension, and if you choke the
inlet to turn down the fire (a very important function in a real stove)
there is no way to get the fire to burn cleanly without adding secondary
air. The Vesto adds it at three different points. If it is cold secondary
air, it can easily quench the flames in the smoke. That is why the Tsotso
worked so well with lousy fuel. The problem with the Tsotso was turning it
down choked the entire fire and it smoked for a long time - until the
charcoaling driven by retained heat ceased. It still tended to burn with
smoke at low power.

There is no question that the Rocket can be made to burn very cleanly, but
the more I hear in detail about the Rocket combustion chamber the more I am
convinced it works best in the ideal conditions of:
constant fuel shape,
constant fuel load,
constant power output and
constant attention (prodding in the fuel).

This _seriously_ is not what we need here. We have widely varying fuel size
and type, differing fuel loads, a need for significant power variation
(about 4:1 minimum) and it must be left alone for at least 30 minutes with
pretty constant power output.

The only Rocket I have used for long enough to know what the chamber is
really like is Scott's stainless steel Eco Stove (2-pot+oven) . With a
chimney, it was really clean, marvellous. It can't be turned down unless
you take out some wood - something I found realistic but inconvenient. It
would be so easy to make the fire chamber walls with holes so as to let in
preheated secondary air. This would take heat from the walls of the chamber
and put it into the incoming air for no net loss of heat and a big gain for
the fire. Then it could have a control on the inlet to turn down the power
when that was desired. There is of course no need for a turn-down capacity
in places which run constant heat demand such as commercial flapjack vendors
etc. All you have to do is maintain a perfect fuel load for the chamber
size.

We need a "Rocket II" with preheated secondary air.

If anyone can make a Rocket chamber that does not have secondary air inlets
and which can control the inlet air to vary the power without smoking, I
will be impressed because it means he/she will have made a stove that can
burn the smoke without oxygen.

The PRoBEC meeting in Vereeniging in 2 weeks is shaping up to be a very
interesting event!

Regards to all
Crispin

From tombreed at ATTBI.COM Tue Feb 25 09:31:25 2003
From: tombreed at ATTBI.COM (Tom Reed)
Date: Tue Aug 10 18:30:15 2004
Subject: [ethos] Re: [STOVES] Combustion
Message-ID: <TUE.25.FEB.2003.073125.0700.TOMBREED@ATTBI.COM>

Dear Dean, Ron and All:

I have long been skeptical about the value of preheating combustion air and
am glad to have Dean give a few more reasons.

1) It is not clear how much preheat you can achieve by passing incoming air
of a few in2 of hot surface and as Dean says, don't rob the combustion
chamber.

2) The viscosity of gases (as opposed to liquids) INCREASES with
temperature, so the hot air won't mix as easily with the pyrolysis gases as
the cold air

3) Addition of a few hundred degrees of air enthalpy could raise flame
temperature by a few hundred degrees, BUT much of stove combustion is
nowhere near stoichiometric due to improper air/fuel ratios. Work on that
first.

TOM REED STOVE SKEPTIC

Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
----- Original Message -----
From: "Dean Still" <dstill@epud.net>
To: "Ron Larson" <ronallarson@qwest.net>; <STOVES@LISTSERV.REPP.ORG>;
"ethos" <ethos@vrac.iastate.edu>
Sent: Wednesday, February 19, 2003 5:20 AM
Subject: [ethos] Re: [STOVES] Combustion

>
> -----Original Message-----
> From: Ron Larson
>
> Dear Ron: Thanks for thrown stones. As far as preheating primary and
> secondary air goes I have a couple of comments. 1.) the heat source for
> preheating air is the combustion chamber. Taking heat from the combustion
> chamber isn't positive because we want highest temperatures there to
achieve
> clean burning. 2.) The air in the 12" Rocket insulated cylinder above the
> combustion chamber exits at around 1850 F . Most of the air below this
> point, above the fire, is as hot or hotter. 3.) We know from tests that
more
> oxygen is not needed in the cylinder. Therefore, preheating secondary air
> has been seen as moot.
>
> But, everyone here would love to preheat primary air, trying to increase
> combustion temperatures. I don't know how to easily do this, except for
> lengthening the fuel magazine, in a sidefeed arrangement. Twin fires, as
in
> a hill climbing Japanese kiln, in side by side fuel magazines, are too
> complicated!
>
> I'm building a blast furnace heating stove now that preheats primary air
> using a fan and closed door into the combustion chamber. Blasts of air,
> mixing air, fuel, flame, plus temperatures well above 2,000F do wonders
for
> clean combustion. But, of course, we have to use refractory cement instead
> of steel for the stove body, which would melt.
>
> All Best,
>
> Dean
> >
> > c. You have not mentioned pre-heating of the air supply (either
> primary or
> >secondary) - a point raised several times by Crispin - but not well
enough
> >argued out on this list. Do you care to guess on its importance in
simple
> >cook stoves?
> >
>
> >
> >Ron
> >
> >
> >
> >
> >
> >>-----Original Message-----
> >>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
> >>Behalf Of Tami Bond
> >>Sent: Monday, February 24, 2003 12:12 AM
> >>To: STOVES@LISTSERV.REPP.ORG
> >>Subject: [STOVES] Combustion
> >>
> >>
> >>Dear Stovers,
> >>
> >>My, we are quiet! Let me throw a couple of stones down the well and see
if
> >>there's any response.
> >>
> >>Alex English recently brought up the 'cliff' aspect of combustion:
> >>transition from poor to good. This is standard combustion behavior that
> >>occurs because a flame is basically a runaway reaction. You need a
certain
> >>amount of stuff to maintain a flame: fuel, and what's called 'free
> >>radicals'-- no, this is not a political debate ;-) Free rads are very
> >>reactive molecules that get the reaction going by nibbling apart more
> >>stable molecules. In burning wood, higher temperature makes both more
fuel
> >>(by letting the volatile matter escape) and more free rads. If these
> >>things start reacting, they release energy, and that makes the
temperature
> >>higher, which makes more fuel+rads, which makes more flame, which raises
> >>the temperature... and boom, there you go. (Of course, you need oxygen
> >>too. I'm assuming that's not in short supply, although it could be.)
> >>Likewise, if the temperature drops enough, you could lose the ability to
> >>burn up the volatile matter that's being ejected from the wood, and
> >>suddenly your fire starts smoking. Along with 'capturing heat' in the
pot,
> >>we need to keep some of it in the fire to keep the reaction going.
> >>
> >>We have talked about combustion chambers and fuels. I haven't heard much
> >>about fuel in the combustion chamber. This seems pretty important too.
> >>Two sticks next to each other keep the heat in the fire by radiating
heat
> >>to each other. That heat would normally be lost to the walls of the
> >>combustion chamber. If the chamber is insulated, great, but... the best
> >>place for the heat is IN THE FIRE until it's carried up to the pot! Two
> >>sticks that are too close to each other prevent oxygen from getting in,
> >>and that makes a bad burn. There is some optimal distance between
sticks.
> >>
> >>The position of fuel in the combustion chamber seems very important in
> >>terms of emissions. However, this is one thing we can't regulate on the
> >>user side. The Rocket chamber has an advantage over the three-stone fire
> >>in that it encourages placement of sticks next to each other, but it
still
> >>carries smoke over the fire where it can be consumed. The Rocket
doesn't
> >>have any requirements for ideal stick distance, though. It's hard to get
> >>the users to load with little sticks instead of big ones-- much less
> >>install them in our 'ideal world' fashion.
> >>
> >>Comments?
> >>
> >>Tami
> >>
> >>
> >
>
>

From snienhuys at SNV.ORG.NP Tue Feb 25 21:58:50 2003
From: snienhuys at SNV.ORG.NP (Sjoerd Nienhuys)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion, shape of sticks
In-Reply-To: <003701c2dd12$b94bd620$4be6fea9@home>
Message-ID: <WED.26.FEB.2003.084350.0545.SNIENHUYS@SNV.ORG.NP>

Dear all,

From dstill at EPUD.NET Wed Feb 19 11:48:04 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <WED.19.FEB.2003.084804.0800.DSTILL@EPUD.NET>

Dear Crispin,

At the last ETHOS conference I was just goofing around doing off the cuff
bag tests of CO on various stoves. When primary air was reduced to decrease
power CO usually went up, as I would expect. We slow down in a car by
reducing the amount of gas not by decreasing supply of air in the
carburetor. Using less fuel to simmer seems a natural method, add more wood
to boil.

I hope that you can lend Peter Scott one of your stoves so we can run it
side by side with other stoves this summer at the ETHOS EXPERIMENTAL
COOKING STOVE GATHERING. We're going to get a bunch of stovers together at
our lab (including the gasifier gang) and by testing all stoves together
come to a shared experience that, I hope, will assist further collaborative
development. Anyway, it should be very interesting and fun. Perhaps you
could come to the meeting? Sometime in June, dates to be determined...

By super insulating the Rocket combustion chamber we hope that heat will be
trapped and therefore temperatures elevated to highest possible levels.
Adding holes to the Rocket internal chimney above the fire would not
increase temperatures because air outside the insulated walls is colder.

If you are not insulating your thin walled metal combustion chamber then, of
course, some amount of heat will be escaping and can be used to heat up
incoming secondary air. The Z stove did the same thing. It had a upright
cylinder full of holes inside a riser sleeve. Natural draft pulled outside
air up the gap between the cylinder and riser sleeve preheating secondary
air which made nice blue jets at the holes in the inner cylinder. The Z
stove was top and mostly batch fed.

It is quite possible to batch feed a Rocket stove, close a door on the fuel
magazine, allowing complete air control and preheating of primary air.
Especially in this case, super insulating the combustion chamber helps to
reduce emissions. The Rocket heating stove adds a fan and turns the stove
into a small blast furnace. But even in the case of a heating stove,
Rockets are designed to assist complete initial combustion.

But restricting primary air to reduce power, instead of reducing metered
fuel obstructs initial combustion. In heating stoves without adequate
secondary combustion smoke can escape from the chimney all night long as the
wood smolders...Depending on preheated secondary air to clean up incomplete
initial combustion is a pattern used in many heating stoves.

As you say, having to push fuel into the combustion chamber could be a
disadvantage. But this pattern allows the user to increase and diminish heat
by simply adding or removing sticks. The Rocket stove can quickly adjust
from low to high power in this manner. A three stone fire is operated in the
same way.

The Rocket stove is trying to achieve complete initial combustion of say two
to eight sticks of wood or the equivalent. Super insulation of the
combustion chamber, metering of the fuel, use of a grate and stick shelf,
relatively small opening in the fuel magazine, etc. assist cleaner burning
of a small to a larger amount of wood controlled by the cook.

Batch feeding and choking the fire to reduce power is another way to reduce
power. Air tight heating stoves rely on this pattern. And like Crispin, the
heating stove designers do everything they can to preheat secondary air
which they want to mix fuel, air, spark and ignite smoke. The two combustion
strategies are divergent however: poking holes in the Rocket combustion
chamber would not accomplish what holes do in the Vesto.

All Best,

Dean

From elk at WANANCHI.COM Wed Feb 26 05:59:28 2003
From: elk at WANANCHI.COM (elk)
Date: Tue Aug 10 18:30:15 2004
Subject: Charcoal Briquetting Machinery
Message-ID: <WED.26.FEB.2003.135928.0300.ELK@WANANCHI.COM>

Hello Musungu;

On 17th Feb. you wrote:

>>We are in the process of establishing a charcoal production and
briquetting unit in Kenya. We are looking for a simple charcoal briquetting
unit. If any one has a new or second hand one available for sale please get
in touch. Give us all the information on production rates and price, if
possible FOB Mombasa.<<

----------

If you, or any other list members are looking for a commercially produced
roller briquetter that makes pillow-shaped briquettes, we have come across
some reasonably priced Indian-made equipment during our recent trip to India
on Shell Foundation business.

The unit we inspected was elegantly simple in design, seemed robust, and
according to the manufacturer, were capable of producing between 900 and
1500 kg per hour of 35 gram briquettes. I'm not clear as to whether that's a
wet or dry basis figure... We were treated to a demonstration using crushed
& carbonised coconut shell with starch binder- and the machine sure puts our
home-built extruders to shame! They were packing up an entire turnkey
briquetting plant, complete with conveyers, sieves, a simple crusher/mixer
and a long tunnel dryer, for shipment to an Eastern European customer.

Though we didn't see any, they also claim to make a high pressure biomass
extruder that is used in Malaysia or Indonesia where dried sawdust is
extruded and subsequently carbonised for sale to customers in Hong Kong and
Japan.

We were very impressed and have now placed an order for use here in Nairobi
with VWB. I don't want to promote a commercial product in this forum, and we
have yet to try the product ourselves (caveat emptor!), but if you or anyone
else is interested in contacting the manufacturer please contact me directly
off-list & I'll answer any questions and provide contact details.

Regards;
elk

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

 

----- Original Message -----
From: "reecon" <reecon@mitsuminet.com>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, February 17, 2003 7:24 PM
Subject: [STOVES] Charcoal briquetting unit.

Hi all,
We are in the process of establishing a charcoal production and briquetting
unit in Kenya. We are looking for a simple charcoal briquetting unit. If any
one has a new or second hand one available for sale please get in touch.
Give us all the information on production rates and price, if possible FOB
Mombasa.

Alternatively we would welcome any ideas on how to fabricate one (DIY) that
could be run by a diesel engine.

Regards,
Musungu.

 

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

From crispin at NEWDAWN.SZ Wed Feb 26 03:37:18 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion - Tom Reed
Message-ID: <WED.26.FEB.2003.103718.0200.CRISPIN@NEWDAWN.SZ>

Dear Tom

I like your response - it seems to have validity, and so does my
interpretation of the innards of the stove, even though is does not
correspond.

Can we think of an experiment that will show us all the true values of these
different analyses?

It would be great if we can think of a way to establish the value of
preheating air, or otherwise. It appears that the main choice for a stove
builder is between insulating the chamber and space above it, and letting
the heat do some work preheating the air on the way to the fire. There is a
lot of yatta-yatta about why they both work but if you try to create a
unified stove theory (UST) there is fundamental conflict between them.

I could build a stove that is capable of both layouts.

We should agree on the parameters and on what and how it is to be tested.

How about it?

Regards
Crispin, the stove skeptic supporter

>Dear Dean, Ron and All:

>I have long been skeptical about the value of preheating
>combustion air and am glad to have Dean give a few
>more reasons.

[snip]
>TOM REED STOVE SKEPTIC

From crispin at NEWDAWN.SZ Wed Feb 26 03:51:22 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion, shape of sticks - Sjoerd
Message-ID: <WED.26.FEB.2003.105122.0200.CRISPIN@NEWDAWN.SZ>

Dear Sjoerd

I have been very concerned in the past to make stoves that people can burn
twigs in because a lot of what is left in a forest (wasted biomass) is
twigs, but in the end it is difficult to make a stove (especially a top
loader) that people are willing to feed twigs into for hours. Putting in
too much causes a lot of smoke and unwanted heat.

I have decided that using larger pieces of wood far more efficiently is just
as valid a path to tread so we now focus on wood up to 200mm long and 100mm
in diameter. That is a pretty good sized chunk and it burns for ages at
1-2kw. 100mm is also a trunk diameter that fast growing fuelwood trees can
reach without crowding each other much. /Sesbania Sesbans/ which has a life
of only about 7 years reaches that size in 3-4 years. It will grow from
seed to 25mm and 3 metres high in 6 months.

>If I watch the women tend the fire during cooking, they spend a lot of time
>moving the sticks around in the opening of the stove, breaking them, and
>even splitting them with a large knife to adjust the fire-heat to there
>exact needs.

Adjusting the heat requirement is a great deal easier of they only have to
move a stone or a lever or a plate which controls the primary air flow. If
there is preheated secondary air available, especially a self-regulating
supply, then the fiddling is greatly reduced and a younger and inexperienced
cook (such as the head of a child-headed household) can burn fuel at a high
efficiency without having to add/split/remove wood.

>Has there been some thought about the needed workload for
>the women to get all these sticks the right size?

I think so.

>Has there been developed a sturdy/powerful woodcutting
>instrument that will ease the chopping process?

The best instrument available here is the modern bow saw. Cheap, sharp,
available. The bush knife (machete) comes in second. Most farming homes
here have both.

Thanks for asking
Crispin

From ronallarson at QWEST.NET Wed Feb 26 10:33:53 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
In-Reply-To: <006d01c2d836$c767d6e0$091e6c0c@default>
Message-ID: <WED.26.FEB.2003.083353.0700.RONALLARSON@QWEST.NET>

Dean - I got some new information from your reply below -thanks - but need
also to ask some questions.

1. You said:
>At the last ETHOS conference I was just goofing around doing off the cuff
>bag tests of CO on various stoves. When primary air was reduced to decrease
>power CO usually went up, as I would expect. We slow down in a car by
>reducing the amount of gas not by decreasing supply of air in the
>carburetor. Using less fuel to simmer seems a natural method, add more wood
>to boil.

(RWL1): I think in most modern combustion devices, one changes both. So in
a "closed" batch combustor (or maybe usually a "pyrolyzer/combustor", one
can only change air. If one gets high efficiency and low emissions, it
doesn't matter if one is only controlling air alone. One gets the effect of
feeding fuel by virtue of a very slowly moving pyrolysis (not gasificaition)
front downward (can't do upward).

I see the present day rural stove as having problems (that Crispin is
solving) exactly because air is not controlled. Being natural to control
fuel does not make it optimum.

2.
> I hope that you can lend Peter Scott one of your stoves so we can run it
>side by side with other stoves this summer at the ETHOS EXPERIMENTAL
>COOKING STOVE GATHERING. We're going to get a bunch of stovers together at
>our lab (including the gasifier gang) and by testing all stoves together
>come to a shared experience that, I hope, will assist further collaborative
>development. Anyway, it should be very interesting and fun. Perhaps you
>could come to the meeting? Sometime in June, dates to be determined...

(RWL2) anything in June after June 20 leaves me out.

3.
>By super insulating the Rocket combustion chamber we hope that heat will be
>trapped and therefore temperatures elevated to highest possible levels.
>Adding holes to the Rocket internal chimney above the fire would not
>increase temperatures because air outside the insulated walls is colder.
>
>If you are not insulating your thin walled metal combustion
>chamber then, of
>course, some amount of heat will be escaping and can be used to heat up
>incoming secondary air. The Z stove did the same thing. It had a upright
>cylinder full of holes inside a riser sleeve. Natural draft pulled outside
>air up the gap between the cylinder and riser sleeve preheating secondary
>air which made nice blue jets at the holes in the inner cylinder. The Z
>stove was top and mostly batch fed.

(RWL3): I am not sure of your nomenclature here. The zz stove (sometimes
called "zip ztove" http://www.zzstove.com/ fits your description somewhat -
but not completely. I don't think it uses a "riser sleeve" nor natural
draft - but does do preheating. I believe the air is forced (one battery,
small fan - for camping) up the outside and then comes down and into the
combustion region. I think it would be fairly easy to run this stove
without pre-heating and hope someone will try. Could you clarify if we are
talking about the same stove. The advertising shows a huge flame that I
don't believe is normal or desirable.

4.
>It is quite possible to batch feed a Rocket stove, close a door on the fuel
>magazine, allowing complete air control and preheating of primary air.
>Especially in this case, super insulating the combustion chamber helps to
>reduce emissions. The Rocket heating stove adds a fan and turns the stove
>into a small blast furnace. But even in the case of a heating stove,
>Rockets are designed to assist complete initial combustion.

RWL4. Would it be possible to do natural draft preheating with this
modification of the Rocket design (ala Crispin (air travel down) or the
ZZstove (air travel both up and down)?) We need as many tests as possible
on the efficiency improvement with preheating - and this sounds possible -
Crispin is claiming that preheating is better than insulation - not that
better insulation shouldn't be preferred over poorer insulation. This is
one of the most important experiments we could be performing - and we are in
big disagreement. I hope 9as Crispin is propising) that we can do as many
tests as possible.

5.
>But restricting primary air to reduce power, instead of reducing metered
>fuel obstructs initial combustion. In heating stoves without adequate
>secondary combustion smoke can escape from the chimney all night
>long as the
>wood smolders...Depending on preheated secondary air to clean up incomplete
>initial combustion is a pattern used in many heating stoves.

RWL5. certainly one cannot go too far with the concept of restricting
primary air supply. Those of us doing charcoal-making stove tests have been
saying that a "turndown ratio" of about 3 was all we could get (not sure of
Crispin's Vesto value - or even if he would call it "charcoal-making") I
apologize for not using the term "gasifier" which I don't think these stoves
are.

6
>As you say, having to push fuel into the combustion chamber could be a
>disadvantage. But this pattern allows the user to increase and
>diminish heat
>by simply adding or removing sticks. The Rocket stove can quickly adjust
>from low to high power in this manner. A three stone fire is
>operated in the
>same way.
>
(RWL6) There are wonderful advantages to being able to adjust fuels. But
this also brings in the disadvantages of usually having either too much fuel
or too little (and usually too much air). In my work with charcoal-making
stoves, I find one of the biggest advantages is with respect to "quick" - I
would say virtually instantaneous - less than one second response time. I
would like to hear from Crispin on his time response - but I'm hoping that
his primary air control allows going from 1 kW to 3 kW in one second - and
level at these values before and after the change in primary air closure
position.

7. >The Rocket stove is trying to achieve complete initial combustion
>of say two
>to eight sticks of wood or the equivalent. Super insulation of the
>combustion chamber, metering of the fuel, use of a grate and stick shelf,
>relatively small opening in the fuel magazine, etc. assist cleaner burning
>of a small to a larger amount of wood controlled by the cook.

(RWL7) I see many nice features of the Rocket - but the question Crispin
is raising is would it be more efficient if the super insulation was
replaced by preheating the air supply. He feels strongly that this is the
case - now we need some tests, as he has called for.
There is also the question of the cook's time spent in metering the fuel.
I hope Crispin can report soon on the test users' appreciation of easy (I
presume) power control.

>
>Batch feeding and choking the fire to reduce power is another way to reduce
>power. Air tight heating stoves rely on this pattern. And like Crispin, the
>heating stove designers do everything they can to preheat secondary air
>which they want to mix fuel, air, spark and ignite smoke. The two
>combustion
>strategies are divergent however: poking holes in the Rocket combustion
>chamber would not accomplish what holes do in the Vesto.

(RWL): I am sure you are right - one can't simply punch holes in the
Rocket - but it would seem that there are some design modifications that
could be made to see if the Rocket principles would be improved with
preheating of air. It seems like you are close when you talk about a batch
mode, which I have not heard you talk about before.

Ron
>
>All Best,
>
>Dean
>
>

From crispin at NEWDAWN.SZ Wed Feb 26 11:30:45 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion - Dean+RWL
Message-ID: <WED.26.FEB.2003.183045.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

Many thanks to Dean [>>] and Ron [>] for the comments. This path should
lead to either a better Rocket or a better understanding of the benefits of
superinsulation.

I am snipping out a lot:

>> I hope that you can lend Peter Scott one of your stoves so we can run it
>>side by side with other stoves this summer at the ETHOS EXPERIMENTAL
>>COOKING STOVE GATHERING.

I can give Peter one in 2 weeks, I hope. I made 6 today which are spoken
for but fortunately I have a couple of parts left.

>>Adding holes to the Rocket internal chimney above the fire would not
>>increase temperatures because air outside the insulated walls is colder.

Lets not rush to conclusions yet. My vision for the Rocket is a concentric
secondary air tube, square or round, one side or 4. The 'back' side would
be best as I observe that the fire impacts the back far more than the other
3 sides because of the way the air enters at the bottom.

>>...some amount of heat will be escaping and can be used to heat up
>>incoming secondary air. The Z stove did the same thing. It had a
>>upright cylinder full of holes inside a riser sleeve. Natural draft pulled
>>outside air up the gap between the cylinder and riser sleeve ...

I agree that the ZZ stove (which was patented BTW) is not natural draft
device and has the air going up, then down and into the chamber. I have
accidentally done almost the same thing on one model of the natural draft
Basintuthu but fed the air into the bottom ?-la-Tsotso. The outside of the
uninsulated body didn't rise about 60 deg C, which is pretty good 'active
insulation'.

RWL4. ...Crispin is claiming that preheating is better than insulation

Well... yes in that I advocate 'active insulation' using air as the
insulator and moving it to the fire. This insulates the stove and adds
oxygen where and when you want it - cheaply too.

>>But restricting primary air to reduce power, instead of reducing metered
>>fuel obstructs initial combustion.

Yes, but...

If there is adequate hot secondary air, it doesn't matter. It will burn the
smoke. It _does_ metter if you don;t have secondary air provided for. As
the retained heat drives the pyrolization, there will be excess smoke,
beyond what is sustainable for more than a few minutes. After the retained
heat is absorbed, then at the lower power setting output continues to burn
the wood, at a lower rate of course. All the time, it requires enough
secondary air to combust the smoke, and the must be hot enough not to quench
the flames. This is not Rocket science (geddit)?

>RWL5. certainly one cannot go too far with the concept of restricting
>primary air supply. Those of us doing charcoal-making stove tests have
been
>saying that a "turndown ratio" of about 3 was all we could get (not sure of
>Crispin's Vesto value - or even if he would call it "charcoal-making")

Aha! When the stoves is turned down after a goot hot burn (especially
initially) it definitely is a gassifier. At a low heat (well choked) it is
also a gassifier. When the wood has mostly burned to charcoal and there
isn't much in the way of volatiles to drive off, the power drops noticeably.
At that time the primary air is opened again and the charcoal is burned. In
a 'normal cycle' a Vesto is a wood burning, wood gassifying, then charcoal
burning stove, in that order. You can do the same thing with coal but not
with charcoal.

>>The Rocket stove can quickly adjust from low to
>>high power in this manner. [taking out fuel]

I agree with this proposition. The Rocket cannot, as far as I understand it
and in my experience, adjust downwards the inflow of extra cold air over the
coals which is no longer required. Whenever you have a perfectly balanced
and burning Rocket, and you remove one of the burning sticks to reduce the
power, you immediately upset the air balance and now have excess cold air.
This will immediately reduce the efficiency. I presume that after a while
the lower power will reduce the draft and things will stabilize at a lower
air flow, but unless the flow is partly choked, it will continue to draw in
excess cold air which simply passes through the stove, cooling the secondary
combustion slightly all the while because the 'chimney' (the whole gas path)
has not reduced in dimension to compensite for the lower power rate. It
/has/ to have a negative effect on the efficiency.

In addition, you have in your left hand a burning stick which is consuming
fuel and not adding to the cooking experience. You have to count that loss
too.

(RWL6) ...I find one of the biggest advantages is with respect to
>"quick" - I would say virtually instantaneous - less than one
>second response time. I would like to hear from Crispin
>on his time response...

The response time upwards is very fast indeed - virtually the time taken to
accelerate the air. I don't know about 1 second, perhaps 3 seconds, and it
rises gradually. The Vesto has a pretty fast downturn time too. I am not
sure how we would determine it - got some ideas? Flame height? Power out?
Air flow? There is a turndown in two stages: initial and post-retained heat
pyrolosis. The lower the stove mass the shorter that 'inertial' stage is.

>>The Rocket stove is trying to achieve complete initial combustion
>>of say two to eight sticks of wood or the equivalent. Super insulation
>>of the combustion chamber, metering of the fuel, use of a grate and
>>stick shelf, relatively small opening in the fuel magazine, etc. assist
>>cleaner burning of a small to a larger amount of wood controlled by
>>the cook.

Yes, but what controls the air? It is free flow all the time?

>>...The two combustion strategies are divergent however:
>>poking holes in the Rocket combustion chamber would
>>not accomplish what holes do in the Vesto.

Wanna bet?

Regards
Crispin

From dstill at EPUD.NET Wed Feb 19 17:23:54 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:15 2004
Subject: Combustion
Message-ID: <WED.19.FEB.2003.142354.0800.DSTILL@EPUD.NET>

Dear Ron,

Wow, this is getting to be quite a discussion. But, I think that we are
identifying differences. THANKS!!

1.)The Rocket gang dislikes the idea of choking off air to a big fire
because you make smoke. We are trying to burn everything at once even not
make many coals.

2.) Crispin likes the immediate turndown of choking off air.

3.) Then he adds lots of preheated secondary air to clean up the smoke.

4.) In a Rocket combustion chamber there is enough oxygen even as heat exits
(1850F) so adding preheated air would not improve the situation. The super
insulated Rocket does not loose much heat which could be used to preheat
secondary air

5.) Crispin's thin metal walls do.

6.) So IMO the Rocket, which never chokes down primary air, provides enough
air initially not to need secondary air. Crispin chokes down the primary air
sometimes so he needs it.

7.) The Rocket does not usually adjust the amount of primary air when
burning two or eight sticks. In real life folks tend to throw away gates,
guillotines, etc. that would regulate primary air in the sidefeed fuel
magazine. CO rates are higher when burning two sticks, lower with a raging
fire. But two sticks don't make much smoke, eight sticks and a screaming
fire can burn 'cleanly' too. In my experience, the Rocket does not produce
much smoke through out the range of two to eight sticks without changing the
amount of incoming primary air. In fact, (Tami can back me up on this):
reducing primary air can greatly increase CO.

8.) I will be studying this. But, I think that Tami and Bryan will determine
reality for us with their better equipment. BIG QUESTION: HOW IMPORTANT IS
IT TO REGULATE HOT AIR AS FUEL AMOUNT CHANGES?

9.) The Z stove was the predecessor to the zz and did not use batteries. It
was tested in Africa by GTZ in the 1980's. Sorry to be confusing.

10.) I am open to all tests!! Saying that preheating secondary air is better
than superinsulating, I think, is stove dependent. Depends what you are
trying to accomplish. No matter. Let's do tests side by side. This is
exactly what I hope to have happen at the summer ETHOS meeting. Ron, thanks
for your dates! It wouldn't be a party without you!! Do others have best
dates?

11.) There is a split here in approaches. To learn from both strategies is
our goal this summer!

12.) The best prepared AT consultant knows everything.

All Best,

Dean

From kchisholm at CA.INTER.NET Wed Feb 26 13:01:19 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion
Message-ID: <WED.26.FEB.2003.140119.0400.KCHISHOLM@CA.INTER.NET>

Dear Ron
>
> Wow, this is getting to be quite a discussion. But, I think that we are
> identifying differences. THANKS!!
>
> 1.)The Rocket gang dislikes the idea of choking off air to a big fire
> because you make smoke. We are trying to burn everything at once even not
> make many coals.
>
It doesn't matter what "the Rocket Gang" like... what is important is what
the stove likes.

> 2.) Crispin likes the immediate turndown of choking off air.
>
If his stove doesn't smoke at turndown, then he is choking primary air.

> 3.) Then he adds lots of preheated secondary air to clean up the smoke.

Probably not.... looks like he does things right in the first place,and does
not have to implement corrective measures.
>
> 4.) In a Rocket combustion chamber there is enough oxygen even as heat
exits
> (1850F) so adding preheated air would not improve the situation.

Some "excess" air is required at the exit from the secondary combustion
zone. "Excess" excess air is by definition, excessive and unnecessary.

The super
> insulated Rocket does not loose much heat which could be used to preheat
> secondary air

Heat used for preheating is not lost. There is a big difference between
"waste heat recovery" and "preheating of air."
>
> 5.) Crispin's thin metal walls do.
>
> 6.) So IMO the Rocket, which never chokes down primary air, provides
enough
> air initially not to need secondary air.

This is bad. No control over the fire.

>Crispin chokes down the primary air
> sometimes so he needs it.
>
That is good... gives control. Thats why his stoves don't smoke at turndown.

> 7.) The Rocket does not usually adjust the amount of primary air when
> burning two

Then the "two stick fire" is getting too much primary air.

> or eight sticks.
It may be getting too much or too little primary air.

In real life folks tend to throw away gates,
> guillotines, etc. that would regulate primary air in the sidefeed fuel
> magazine. CO rates are higher when burning two sticks,

Of course. This is entirely expected. Excess primary air is quenching the
process.

lower with a raging
> fire.

"lower" CO could mean several things. Could be too much primary air, causing
a quenching effect.

But two sticks don't make much smoke, eight sticks and a screaming
> fire can burn 'cleanly' too. In my experience, the Rocket does not produce
> much smoke through out the range of two to eight sticks without changing
the
> amount of incoming primary air.

Clearly, you have too much primary air for small fires

In fact, (Tami can back me up on this):
> reducing primary air can greatly increase CO.
>
If you have a properly balanced fire, then Tami would agree effusively.
If you have significant excess primary air, then reducing primary air can
REDUCE CO, by reducing the quenching effect.

> 8.) I will be studying this. But, I think that Tami and Bryan will
determine
> reality for us with their better equipment. BIG QUESTION: HOW IMPORTANT IS
> IT TO REGULATE HOT AIR AS FUEL AMOUNT CHANGES?
>
2+2 = 5... the answer is right but the question is wrong. :-)

> 9.) The Z stove was the predecessor to the zz and did not use batteries.
It
> was tested in Africa by GTZ in the 1980's. Sorry to be confusing.

Sorry, but I am not familiar with the Z or ZZ stove.
>
> 10.) I am open to all tests!! Saying that preheating secondary air is
better
> than superinsulating, I think, is stove dependent. Depends what you are
> trying to accomplish.

"Stove dependant" and "what you are trying to accomplish" are the key
considerations in setting up tests.

No matter. Let's do tests side by side. This is
> exactly what I hope to have happen at the summer ETHOS meeting.

"Side by side tests" could be not very helpful if the stove were
significantly different, or if their intended purposes were significantly
different.

Kindest regards,

Kevin

From psanders at ILSTU.EDU Wed Feb 26 14:58:29 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:16 2004
Subject: [ethos] Re-defining What is a stove?
In-Reply-To: <000001c2dc91$339bc390$7517510c@homep7vz76bnq4>
Message-ID: <WED.26.FEB.2003.135829.0600.PSANDERS@ILSTU.EDU>

Wilfred,

Thanks for the message. I note that it did not go to the others on the
ETHOS list serve, so I am sending it (below) to the Stoves List Serve
(because I will avoid sending identical copies to both lists, and I feel
that this message is more along the lines of the Stoves list.) Are you
(Wilfred) on the Stoves list serve?

About your question concerning classification of stoves,
For solar cookers, the 4 aspects can be applied as follows:

source = sun
generator of heat = the shiny surfaces
captor-of-heat for actual use = pot or other at the focal point of the
reflector
user-practices = daylight hours, sunny days, etc,

When making a classification system/terminology, divide down to the small
units, then group appropriately, and do NOT let "combinations" such as heat
capture and heat generation overlap.

Paul

At 09:46 PM 2/24/03 -0800, Wilfred Pimentel wrote:
>Dear Paul
>
>The solar cooker committee composed of Jack Anderson, Bruce Stahlberg,
>and myself have begun corresponding on finding the proper terminology
>when referring to solar cookers, fuel efficient stoves, heat retained
>cookers, biomass stoves, and ecological cookers (term used by Dave
>Whitfield in Bolivia for all types of cookers- rocket stoves, solar box
>cookers, solar panel cookers, SK 14's,).
>
>Does anyone have a solution to simplify this terminology? I do use
>common names like haybox, panel solar cooker, and rocket stove- I like
>the term biomass stoves which covers many devices but is not specific.
>To a lay person some of these names sound strange. For the end user
>cooked food is all that he/she cares about.
>
>Those of us giving programs at Rotary luncheons and conferences are
>concerned- please! Any help??
>
>Dr. Wilfred Pimentel, Member Rotary Club of Fresno
>1035 East Cambridge
>Fresno, CA 93704
>Tel 559-222-4193
>Fax: 559-222-4193
>e-mail solarcook@att.net
>
>
>
>-----Original Message-----
>From: owner-ethos@vrac.iastate.edu [mailto:owner-ethos@vrac.iastate.edu]
>On Behalf Of Paul S. Anderson
>Sent: Monday, February 24, 2003 2:49 PM
>To: The Stoves Discussion List
>Cc: wesly_burrows@yahoo.com; Apolin?rio J. Malawene; Carlos lucas;
>ethos; Herman Bos
>Subject: [ethos] Re-defining What is a stove?
>
>Stovers,
>
>Because our "definitions of stoves" are so diverse, I would like to
>refine
>my earlier (last month?) message about the 4 critical aspects of
>stoves. The four are VERY interrelated, but IMHO it helps to express
>the
>four aspects separately.
>
>1. Source of (heat) energy -- was called fuels -- ultimate source
>is
>sun and uranium, but we are really referring to what is commonly called
>a
>"fuel". Note, electricity, (originating from hydro or wind or fossil
>fuel
>or other more basic energy sources) is also delivered to some homes as a
>
>"fuel," as are wood pieces and cow dung and other biomass, and
>coal/oil. Most stoves are specific to a single "fuel" or fuel type, but
>
>some are more flexible in their energy sources. Here we do not really
>use
>the term "efficiency" of an energy source, but we do refer to the energy
>
>value of each type of fuel, some per kilogram, others per liter, others
>per
>..... We need clarity whenever we compare between fuels.
>
>2. Energy (heat) generation unit -- was called the combustion
>chamber,
>but that old name caused questions about the peripheral aspects (fans
>and
>insulation, etc) that are key components to some heat generation
>units. (Other energy, such as mechanical force generated by internal
>combustion engines, is related, but is not of much interest to our
>stoves
>group that focuses on cooking and some on room heating.) An electric
>hot-plate is a heat generation unit, as is a Rocket "unit" or my Juntos
>gasifier "unit". Different technologies trying to do the same task,
>which
>is to generate heat. "Efficiency" here refers to conversion of the
>"fuel"
>into heat energy that is delivered to the operational outlet of the heat
>
>generation unit. Smoke is lost energy, so we try to avoid a "poor
>burn". Heat radiated from the sides of the generation unit can be
>considered lost in most cases, but if it is valued as an addition to
>room
>heat, then the laterally radiated heat can be given a value as part of
>the
>total efficiency. We need clarity whenever we compare different heat
>generation units.
>
>3. Energy (heat) capture unit -- was called stove structure (too
>vague). Energy capture covers the stove aspects "that deliver the heat
>into the pot or plancha" etc. "Efficiency" here refers to whatever it
>takes, including supportive legs to capture the heat for useful
>purposes. We need clarity whenever we make statements about the heat
>capture units.
>
>4. User-practices (the "Human-factor") impacting energy (heat)
>utilization --- was called cooking practices. This refers to
>how
>different people and different cultures would make use of the above 3
>"aspects" of the "stove." If the cook does not like or will not use a
>"stove" because of issues of fuel, or combustion, or types of pots, then
>
>the "stove" is not viable in that situation. And we need clarity and at
>
>least continual recognition about user-practices of heat utilization.
>
>ALL four are ESSENTIAL considerations about heat in "stoves":
>
>source (of heat)
>generation (of heat)
>capture-for-use (of heat)
>user-practices (of heat) (the "Human-factor")
>
>I have written about this because the "Tower of Babel" of stoves
>discussions and stove comparisons is daunting, with frequent cross-overs
>
>between these four vastly different aspects of "stoves," even without
>mentioning the monetary aspects of each of the four.
>
>Note to Dean Still: At our coming June workshop at Aprovecho, we can
>have
>activities and discussions that relate to each of the 4 aspects, but I
>suspect that our "common ground" of interest is in the "generation of
>heat"
>and how the Rocket and the Juntos and other heat-generation-units
>function
>and can assist each other.
>
>And I will attempt to clearly identify these 4 aspects in the meetings
>in
>South Africa on 10 to 14 March. Peter S., Crispin P-P., John D.,
>myself,
>and others on the Stoves List Serve will be there.
>
>Love them stoves!!!!!!!
>
>Paul
>
>
>Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
>Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
>Dept of Geography - Geology (Box 4400), Illinois State University
>Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
>E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Wed Feb 26 15:25:13 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:16 2004
Subject: Questions about THE DEVELOPMENT AND PRODUCTION OF
=?iso-8859-1?Q?=93WOOD?= =?iso-8859-1?Q?_GAS=94_STOVE?=
In-Reply-To: <E18nZUd-0005KU-00@eagle.dnspropagation.com>
Message-ID: <WED.26.FEB.2003.142513.0600.PSANDERS@ILSTU.EDU>

At 02:27 AM 2/25/03 -0500, ARECOP Secretariat wrote:

......

>The Asian Institute of Technology has for several years developing and
>testing on the production of wood gas stove and has been quite
>advanced. Therefore expected that ARECOP will collaborate with AIT in
>holding and conducting training for the network in Asia on the
>development and production of wood gas stove.

^^^^^^^^
Hello,

I have left your entire message below because it did not seem to go to the
Stoves list serve.

My question is for information about what you have developed in the field
of "wood-gas" stoves. Tom Reed and I have done considerable work, but I
am not able to determine how much is different and how much is identical or
similar. Our work is described on the Internet at various
sites. see www.trmiles.com/stoves

We know of the gasifier of cardomom (?) drying, but that technology is
different from ours.

Any further information about your gasifiers would be appreciated.

Please give our greetings to your conference participants that know of our
work via HEDON and other sources. It will be nice when we can all have
more information flows between the different groups.

Best wishes for your conference, which is one week after the ProBEC GTZ
stoves conference in South Africa that several of us will be
attending. Looking forward to knowing about your meeting. Please send us
info about presentations planned, etc.

Sincerely,

Paul
******************************
>Dear all
>
>Please take note on the announcement on training on wood gas stove
>below. Announcement and Application form can be downloaded at
>www.arecop.org.
>
>For all other inquiries, please contact ARECOP Secretariat
>_______________________________________________________________-
>
>
>REGIONAL TRAINING ON THE DEVELOPMENT AND PRODUCTION OF ?WOOD GAS? STOVE
>
>19-21 March 2003, Bangkok, Thailand
>
>
>INTRODUCTION
>
>The Asia Regional Cookstove Program (ARECOP) is a network that concern
>on the development and application of improved cookstove in the Asia
>region. ARECOP was established in 1990 and based in Yogyakarta,
>Indonesia.
>
>During its networking activities in the past ten years, especially in
>the past three years there seems to be a growing requirement for
>cleaner combustion improved stove. This is especially due to the fact
>of the constantly increasing prices of fossil fuels such as kerosene
>and gas. Apparently, requirement for cleaner combustion biomass fuel
>stove as alternative needs to be looked into and prepared at early
>stage so that when many felt too high to afford kerosene and gas and is
>forced to go down the energy ladder back to use the biomass fuel, an
>improved stove technology with cleaner combustion and modern already
>exists.
>
>In addition, there is a high concern from the world wide under the
>kyoto protocol to reduce emmisions to help reduce green house gases.
>Improved cookstove with good combustion, when used by large number of
>people will certainly contribute to the reduction of emmisions.
>
>Health issue is another issue on the use of biomass fuel and
>traditional stove as there is a strong indication that smoke produce
>from traditional biomass fuel cookstove can cause a number of health
>problems such as Acute Respiratory Deseases, Lung cancer, Cataract, etc.
>
>Thus far, ARECOP introduced and build capacity of many network members
>in the Asia region through training on how to design, and disseminate
>sustainably improved cookstove. The technology however is still limited
>to improving the traditional stove with design in accordance to the
>wish and need of the respective target group.
>
>Yet, a more modern type of stove is needed to be developed, introduced,
>and disseminated so that the community can have alternative in choosing
>their improved cooking stove.
>
>In addition, such improved stove maybe more interesting to policy
>makers as it looks modern yet the fuel use is renewable, an issue that
>is very much the concern of many countries.
>
>The Asian Institute of Technology has for several years developing and
>testing on the production of wood gas stove and has been quite
>advanced. Therefore expected that ARECOP will collaborate with AIT in
>holding and conducting training for the network in Asia on the
>development and production of wood gas stove.
>
>Purpose
>
>The training course is designed to provide opportunity to ARECOP
>network participants who have been involved and dedicated to improved
>cookstove program in their respective country to have new alternative
>in improved cookstove technology that uses modern type of biomass fuel
>stove technology with cleaner combustion.
>
>
>Objectives:
>
>At the end of the course the participants are expected:
>
>1. To be aware of the existence of modern biomass stove technology
>2. To understand the basic principles of wood gas stove technology
>3. To have the knowledge and skill in making and producing wood gas
>stove
>4. To be able to apply the knowledge and skill gain into their works
>upon coming back to their respective organization for the planning and
>implementation of wood gas improved stove program.
>
>
>Organization of the training
>
>The training will be jointly organized by ARECOP and the Asian
>Institute of Technology (AIT) and HSE Greenfield.
>
>Language of Instruction
>
>The training course will be conducted in Englsih
>
>Resource Person
>
>The resource persons/trainers will be from AIT
>
>Schedule of training
>
>19 ? 21 March 2003.
>
>Training venue
>
>AIT , Bangkok, Thailand
>
>Number of participants
>As there will be a lot of practical work, the training will only
>accommodate a maximum of 15 participants from the ARECOP network
>countries
>
>Country of participants
>
>ARECOP network countries : Bangladesh, India, Nepal, Sri Lanka,
>Pakistan, Bhutan, Indonesia, Philippines, Thailand, Lao, Myanmar,
>Cambodia, Vietnam, China.
>
>Qualification for training participants
>
>To be eligible for the course, the applicant must :
>
>1. Be nominated by their organization
>2. Be a citizen of the nominating country
>3. Have at least been involved in Improved cookstove program for 2
>years and preferably those who are still active and having on going
>program or projects
>4. Have strong technical background in ICS.
>5. Be in good health
>
>
>Procedure for application
>
>Applicants must fill in the :
>1. Application form (attached);
>2. Write an essay on how useful this course is to his or her career and
>the nominating organization and the potential target community;
>
>And send it either by e-mail or fax to :
>The ARECOP Secretariat
>Fax : 62-274-885423
>e-mail : secretariat@arecop.org
>
>The deadline of application submission is 4th March, 2003
>
>The ARECOP secretariat will inform selected participants on 7th March,
>2003
>
>
>ARECOP SPONSORSHIP
>
>ARECOP has limited fund available to support travel and/or accomodation
>of some participants. Depending on the available resources and the
>number of application received, ARECOP will make a selection of
>participants to be fully or partly supported.
>
>Therefore applicants are expected to look for funding support to ensure
>your participation in the training.
>
>International travel
>
>ARECOP will only provide international ticket from the nearest
>international airport to Bangkok International Airport. Selected
>participants shall assume responsibility for visa application fee,
>airport taxes and other expenses incurred during the travel between
>home country and the training venue in AIT complex, Thailand.
>
>Other travel expenses
>
>Particiapants shall be responsible for visa application fee, travel and
>airport taxes, and all other expenses incurred during the travel
>between their home country and the training venue, vice versa.
>
>Visa
>
>Participants that are not from the ASEAN countries will need visa to
>enter Thailand. Participants should be responsible to obtain their visa.
>
>
>Allowances and expenses
>
>1. Training manual, venue and materials will be provided by AIT
>2. Accomodation on sharing basis, including breakfast and lunch will be
>paid directly by ARECOP
>3. A modest living allowance of $ 20/day will be provided by ARECOP to
>cover dinner and other incidental expenses such as laundry telephone
>calls, etc.
>4. ARECOP will not cover any insurance to participants therefore those
>selected should arrange for their own insurance.
>
>
>
>----
>Asia Regional Cookstove Program Secretariat
>PO BOX 19, YKBS, Bulaksumur, Yogyakarta
>62-274-885423
>secretariat@arecop.org
>www.arecop.org
>
>--

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From ronallarson at QWEST.NET Wed Feb 26 15:45:05 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion, shape of sticks - Sjoerd
In-Reply-To: <001701c2dd89$03003b00$2a47fea9@md>
Message-ID: <WED.26.FEB.2003.134505.0700.RONALLARSON@QWEST.NET>

Crispin (cc. Sjoerd, Ray Wijewardene, and all stovers)

1. Today you said:

>I have decided that using larger pieces of wood far more
>efficiently is just
>as valid a path to tread so we now focus on wood up to 200mm long and 100mm
>in diameter. That is a pretty good sized chunk and it burns for ages at
>1-2kw. 100mm is also a trunk diameter that fast growing fuelwood trees can
>reach without crowding each other much. /Sesbania Sesbans/ which
>has a life
>of only about 7 years reaches that size in 3-4 years. It will grow from
>seed to 25mm and 3 metres high in 6 months.
>

RWL1: This must be for a stove different than your Vesto
http://www.newdawn-engineering.com/website/stove/singlestove/vesto/vesto1.ht
m which seem to have a combustion chamber into which you could only put one
such diameter. Could you clarify? What is the maximum size stick you could
use with a Vesto (and please remind us of the combustion chamber diameter.
When you are using the large sticks - what is the minimum number used?
Are you stacking them in a vertical orientation (side by side)?

2.
>Adjusting the heat requirement is a great deal easier of they only have to
>move a stone or a lever or a plate which controls the primary air flow. If
>there is preheated secondary air available, especially a self-regulating
>supply, then the fiddling is greatly reduced and a younger and
>inexperienced
>cook (such as the head of a child-headed household) can burn fuel at a high
>efficiency without having to add/split/remove wood.

RWL2: I am wondering about the correlation between preheating,
self-regulation, and ease of use - not clear. I can see higher efficiency -
but in my work, which also somehow achieves a degree of self-regulation on
the secondary air - I don't see a direct relationship between preheating and
fiddling/ The fiddling is reduced in charcoal making stoves by virtue of
being able to control primary air and not having to touch again for tens of
minutes. It is still not clear to me whether your Vesto is operating in
that mode.

3. (Sjoerd first)
>>Has there been some thought about the needed workload for
>>the women to get all these sticks the right size?
>
>I think so.
>
>>Has there been developed a sturdy/powerful woodcutting
>>instrument that will ease the chopping process?
>
>The best instrument available here is the modern bow saw. Cheap, sharp,
>available. The bush knife (machete) comes in second. Most farming homes
>here have both.
>
>Thanks for asking
>Crispin
>
(RWL3: I once saw an article on the relative efficiency of the saw and
the axe (presumably similar to the machete) - huge difference - maybe a
person could cut two or three times (exact data forgotten) more per day with
a saw. We apparently see fewer saws than axes in remote areas because of the
difference in ease in keeping them sharp.

But I would like to think that the optimum size branch or stem for fuel
wood for most family size units is appreciably smaller than 100 mm. 50 mm
sound better as an upper limit. With the Vesto, I would have guessed 25 mm.
With commercial scale combustion needs, then 100 mm sounds fine - but that
isn't 1-2 kW. If Crispin is able to achieve combustion of the 100 mm scale
in a Vesto, this is truly amazing - and definite proof of the value of
preheating (and also of reflective surfaces I think).

It wouldn't surprise me that at the smaller (25 mm scale) that the machete
might be the tool of choice. Ray Wijewardene has thought about these things
a lot. Ray?

Ron

From crispin at NEWDAWN.SZ Wed Feb 26 15:54:18 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:16 2004
Subject: : Combustion - Kevin
Message-ID: <WED.26.FEB.2003.225418.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

I was going to respond to Dean but i can't add anything to what Kevin has
said.

Regards
Crispin

++++++++

> Wow, this is getting to be quite a discussion. But, I think that we are
> identifying differences. THANKS!!
>
> 1.)The Rocket gang dislikes the idea of choking off air to a big fire
> because you make smoke. We are trying to burn everything at once even not
> make many coals.

[etc.]

From crispin at NEWDAWN.SZ Wed Feb 26 16:10:32 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:16 2004
Subject: RE Combustion, shape of sticks - SRon
Message-ID: <WED.26.FEB.2003.231032.0200.CRISPIN@NEWDAWN.SZ>

Dear Ron

>>...we now focus on wood up to 200mm long and 100mm
>>in diameter.

>RWL1: This must be for a stove different than your Vesto
>http://www.newdawn-engineering.com/website/stove/singlestove/vesto/vesto1.h
tm
> which seem to have a combustion chamber into which you could only put one
>such diameter.

Yes, it is the same stove and we put in one piece, on top of a very small
initial knidling fire (as mentioned previously). Vivienne Abbott found that
pieces 60-70 dia and 100 long were great as she could put in one for
simmering and 2 for cooking. The 200mm height limit is deliberate but not
absolute: I have to leave enough room above the fuel to burn the smoke
before it hits the pot.

>What is the maximum size stick you could use with a Vesto

The chamber is 125 inside dia and it can take 100x200mm long as a practical
max. Note that this subject also harks back to the biomass briquettes which
are 100 in diamater but have the fire on the inside. Remember how I
objected that I can get preheated air of they burn on the inside hole?

>Are you stacking them in a vertical orientation

Yes, on top of each other when necessary.

2.
>>If there is preheated secondary air available, especially
>a self-regulating supply

>RWL2: I am wondering about the correlation between preheating,
>self-regulation, and ease of use - not clear.

I am hoping to achieve a completely self-regulating preheated secondary air
supply but eventually I will have to mathematically model the stove air
flows on a computer and it is beyond my capacity to do so. I am hoping some
in Pune will assist....(are you listening...?)

>I don't see a direct relationship between preheating and fiddling

Hopefully there shouldn't be any.

>The fiddling is reduced in charcoal making stoves by virtue of
>being able to control primary air

I think fiddling is reduced any time things are constant and there is enough
fuel. If something can simmer for 30 minutes without touching the stove it
is a winner as far as I can see. That is a long time for a low-fuel-load
stove.

I am hoping to do some top lighting experiments to see if I can get a
nearly-gassifying condition with very nearly constant power for, say, 45
minutes at about 15 gm burned per minute, then open up the primary air and
burn the charcoal. It might be smokeless throughout.

>But I would like to think that the optimum size branch or stem for fuel
>wood for most family size units is appreciably smaller than 100 mm.

I think 60mm is a good max. Easy to cut and containes lots of mass.

>With the Vesto, I would have guessed 25 mm.

Much bigger. It burns on the outside remember, you can only get lower power
without splitting it once or twice. In practice to get 4Kw you have to have
more surface area.

>...this is truly amazing - and definite proof of the value of
>preheating ...

The /primary/ air - it is difficult to keep such a fire going with a single
piece unless the incoming air is hot.

Regards
Crispin

From pverhaart at OPTUSNET.COM.AU Wed Feb 26 18:25:55 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:16 2004
Subject: Charcoal Briquetting Machinery
In-Reply-To: <18nzFW-0005bD-00@ns2.wananchi.com>
Message-ID: <THU.27.FEB.2003.092555.1000.PVERHAART@OPTUSNET.COM.AU>

At 13:59 26/02/03 +0300, you wrote:
>Hello Musungu;
>
>On 17th Feb. you wrote:
>
Chop

>Though we didn't see any, they also claim to make a high pressure biomass
>extruder that is used in Malaysia or Indonesia where dried sawdust is
>extruded and subsequently carbonised for sale to customers in Hong Kong and
>Japan.

Last year in Bali, we saw charcoal briquettes being used for making Satay.
Asking around, we didn't get very far until somebody suggested a look into
a supermarket.
Yes, bags of briquettes, made somewhere in Surabaya.
Square cross section, 36 mm. a hole in the centre of about 10 mm and of
random length, clearly extruded.
Peter Verhaart

From Carefreeland at AOL.COM Wed Feb 26 19:00:31 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:16 2004
Subject: Charcoal Briquetting Machinery
Message-ID: <WED.26.FEB.2003.190031.EST.>

In a message dated 2/26/03 6:01:22 AM Eastern Standard Time, elk@WANANCHI.COM
writes:

DD: Dan Dimiduk replys
>
> If you, or any other list members are looking for a commercially produced
> roller briquetter that makes pillow-shaped briquettes, we have come across
> some reasonably priced Indian-made equipment during our recent trip to
> India
> on Shell Foundation business

DD Hello Elk,
Long time no response, life must be even crazier for you than me
lately?
I am interested in knowing the general price shipped to the USA and
any other significant specifications. If the current dustcloud I am working
in clears a little more, (I think it's actually blowing snow this month) I
may see a way to finally enter the real charcoal business.
DD You can respond to me off list, but I think quite a few members may now
be interested in the charcoal business. I am noting a particular intrest in
small farm sized operations and ready made pyrolisis devises. Any stovers
agree with that?
Your Long lost cyber friend,
Dan Dimiduk

From ronallarson at QWEST.NET Wed Feb 26 20:01:34 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:16 2004
Subject: Charcoal Briquetting Machinery
In-Reply-To: <5.1.0.14.2.20030227091916.00a7f730@mail.optusnet.com.au>
Message-ID: <WED.26.FEB.2003.180134.0700.RONALLARSON@QWEST.NET>

Elsen, Piet, et al

I sure would like to know the cost of these extruded sawdust briquettes
before and after charcoaling. A charcoal-making stove owner ought to be
quite willing to take them as sawdust and return a charcoaled briquette - at
no cost. Everyone wins - even we in the US if the alternative large scale
approach puts a lot of global warming gases (CO, CH4, etc) into the
atmosphere. The transaction costs won't allow this for each individual -
but a village organization should be possible for the differential cost
between the raw and charcoaled prices.

Ron

 

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of Peter Verhaart
>Sent: Wednesday, February 26, 2003 4:26 PM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: Re: [STOVES] Charcoal Briquetting Machinery
>
>
>At 13:59 26/02/03 +0300, you wrote:
>>Hello Musungu;
>>
>>On 17th Feb. you wrote:
>>
>Chop
>
>
>>Though we didn't see any, they also claim to make a high pressure biomass
>>extruder that is used in Malaysia or Indonesia where dried sawdust is
>>extruded and subsequently carbonised for sale to customers in
>Hong Kong and
>>Japan.
>
>
>Last year in Bali, we saw charcoal briquettes being used for making Satay.
>Asking around, we didn't get very far until somebody suggested a look into
>a supermarket.
>Yes, bags of briquettes, made somewhere in Surabaya.
>Square cross section, 36 mm. a hole in the centre of about 10 mm and of
>random length, clearly extruded.
>Peter Verhaart
>
>

From Carefreeland at AOL.COM Wed Feb 26 21:32:00 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion conversation
Message-ID: <WED.26.FEB.2003.213200.EST.>

Hi Stovers,
I have been struggling with time to follow this string with peaked
interest. Currently though, I am being whiplashed directly with economic
turbulence. I can demonstrate this is probably caused in part by the very
greenhouse effect we are all trying desperately to reduce. Remember that I
have predicted record pendulum swings in the climate, due to mother earth
shaking off the excess heat buildup. First things first.
On the combustion subject. If we compare controlling air on a stove
to controlling the throttle on an auto, remember two things. 1. The
throttle controls not just air but also the venturi effect in the carburetor.
The throttle does control the amount of mixture, plus, the percentage amount
of fuel. 2. When we throttle the primary air on a stove, we also control the
intensity of the gasification process, the throttle. The preheated secondary
air controls the choke.
Remember that pyrolisis rate is controlled by the thermal energy present
to gasify the biomass. That in turn, is controlled by the quantity of
oxygen(air) available from primary air, times the efficiency of pyrolisis to
generate heat, minus heat losses.
Weather the primary combustion is complete or incomplete has little
bearing on the total energy released at this primary stage. It only affects
the amount of fuel left for later, and the mixture of the gas produced. The
percentage of this energy directly utilized for gasification does have a role
here.
If a larger amount of energy is "used up" gasifing the biomass, then
less realitive pyrolisis heat is avalible to be passed on for secondary
combustion. Just as boiling a pot of water will cool the stove exhaust more
than an empty stove burning the same quantity of fuel. A less efficient
stove which leaks heat, or a high mass stove warming up, will also leave less
excess energy for preheating secondary combustion air. It has a lower air
flow from the temperature induced draft though, so the heat is concentrated
in less gas.
The richness of the resulting mixture of gas with residual oxygen or
inert gasses is a second independent factor. Using the heat from pyrolisis
for preheating secondary air has a balancing effect on secondary combustion
temperature.
Then we have to remember that it is the pyrolisis that GENERATES heat in the
primary process. This is where moisture content has a huge role. Driving
off steam steals a lot of energy from the pyrolisis reactions right from the
start. Burning wet wood is not unlike running a motor with moisture in the
gas, it needs more choke.
IF the lost primary heat is then recycled for preheating secondary
combustion air, then the heat is recycled in another way. Can we then, in
this set up, control the total combustion by controlling the primary air
flow? The secondary air flow control would compensate for the efficiency of
pyrolisis. The secondary air would in effect balance the primary combustion
by also controlling the heat available for gasification.
With this configuration the need for secondary air would be more
dependent on gasification(primary) temp + moisture content. More moisture
and cooler primary firebox needs less secondary air and visa versa. Or is my
dyslexia fooling me again?
I am having trouble picturing this effect used in a design. Maybe I
have just spent too much time out driving at night, looking at white fluffy
ice crystals swirling around me in the cold wind. On the other hand, maybe I
am onto something. Maybe Crispin, Ron, Tom or someone who can follow all of
this, can explain this equation better than I.
On the subject of the weather controlling economic turbulence? One of
my customers has nearly gone bankrupt due to the excessive snow we are
experiencing combined with weak background economic conditions. Try well
over 20 drifted inches, a record for this month. They are leaving me waiting
until spring for most of my hard earned Winters income. A new customer has
stepped up to the plate, recognizing the value of my 18 years of snow removal
expertise. This customer has hired me to clean the mess left by a less
experienced snow removal contractor. In three days with this customer, I
have made a third of what I have been owed for a winter of work with the
first.
What this may say, is that it doesn't matter if the biomass is burned
in the first or second stage, what matters is that it is burned well when it
finally reaches the exhaust.
Someone explain, what I have just explained. I'm going to sleep. I
am expecting a phone call early in the morning. They just might keep me and
my bobcat, literally up to our eyeballs, re-moving tons of compacted, rained
on, and frozen solid, SNOW !
Then I'll be ready to fire up that woodstove with Hickory and Oak. I'll thaw
back out, and wait till payday in late March. About then, the weather will
take another wild ride into summer.
Till then, Stove away with out me,
Dan Dimiduk

From psanders at ILSTU.EDU Wed Feb 26 23:05:42 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion
In-Reply-To: <16e.1b2dc204.2b8cac00@aol.com>
Message-ID: <WED.26.FEB.2003.220542.0600.PSANDERS@ILSTU.EDU>

At 06:22 AM 2/25/03 -0500, Carefreeland@AOL.COM wrote:

>Let me suggest that it is the distance between the sticks, realitive to the
>temperature maintained there, and air flow velocity, that causes this balance
>or lack thereof. The distance allows a certain velocity of airflow,
>maintaining a balance of both retention of heat, and presentation of oxygen
>to the combusting gasses.

While the above can be true, consider the case of biomass stoves that have
real, true, major control over the amount of air that can reach the areas
of pyrolysis and combustion. THEN the spacing between the fuel is NOT the
key to controlling the air flow velocity or amount. That means that
positioning is less important.

Those of us who emphasize that our stoves have significant air control BY
DEVICE and not by the stack of fuel include:
Crispin P-P, John Davies, Tom Reed, me (Paul), and Lanny (with very nice
sliding "doors"). The Rocket seems to be moving toward more control of the
air, but appears to be rather open currently.

There are other stoves to add to this list. Sorry I do not know all of
them. Please send additional names and describe their "air control devices".

Paul
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From psanders at ILSTU.EDU Wed Feb 26 23:32:05 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion
In-Reply-To: <061b01c2dcda$95247190$c281fd0c@TOMBREED>
Message-ID: <WED.26.FEB.2003.223205.0600.PSANDERS@ILSTU.EDU>

At 07:31 AM 2/25/03 -0700, Tom Reed wrote:

>I have long been skeptical about the value of preheating combustion air

Stovers,

My work with pre-heating (and no pre-heating in same stove) has had mixed
results. I am not convinced yet either way.

When I do stove experiments in -5 degree C Illinois winter weather, I KNOW
that without pre-heating I will have problems. When too cold and without
pre-heating, the fire just will not do well if the fire is small (as it
should be for domestic cooking).

But I also understand Tom's points.

I believe that the clarification will not come until we can have actual
results from controlled experiments. Anyone doing such things, or planning to?

Paul

 

 

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From elk at WANANCHI.COM Thu Feb 27 00:10:37 2003
From: elk at WANANCHI.COM (elk)
Date: Tue Aug 10 18:30:16 2004
Subject: Charcoal Briquetting Machinery
Message-ID: <THU.27.FEB.2003.081037.0300.ELK@WANANCHI.COM>

Ron;

Be interesting to try the extruded biomass briquettes in a charcoal-making
stove Ron. Can you get 'fuel logs' in Colorado? I suspect that the burn rate
would be slower due to the briquettes relatively high density (compared to
wood). Do you think that this would be an advantage or impediment? The size
& shape- length, in particular- should be appropriate for the vertical fuel
load.

elk

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

 

----- Original Message -----
From: "Ron Larson" <ronallarson@QWEST.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, February 27, 2003 4:01 AM
Subject: Re: [STOVES] Charcoal Briquetting Machinery

> Elsen, Piet, et al
>
> I sure would like to know the cost of these extruded sawdust
briquettes
> before and after charcoaling. A charcoal-making stove owner ought to be
> quite willing to take them as sawdust and return a charcoaled briquette -
at
> no cost. Everyone wins - even we in the US if the alternative large scale
> approach puts a lot of global warming gases (CO, CH4, etc) into the
> atmosphere. The transaction costs won't allow this for each individual -
> but a village organization should be possible for the differential cost
> between the raw and charcoaled prices.
>
> Ron
>
>
>
> >-----Original Message-----
> >From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
> >Behalf Of Peter Verhaart
> >Sent: Wednesday, February 26, 2003 4:26 PM
> >To: STOVES@LISTSERV.REPP.ORG
> >Subject: Re: [STOVES] Charcoal Briquetting Machinery
> >
> >
> >At 13:59 26/02/03 +0300, you wrote:
> >>Hello Musungu;
> >>
> >>On 17th Feb. you wrote:
> >>
> >Chop
> >
> >
> >>Though we didn't see any, they also claim to make a high pressure
biomass
> >>extruder that is used in Malaysia or Indonesia where dried sawdust is
> >>extruded and subsequently carbonised for sale to customers in
> >Hong Kong and
> >>Japan.
> >
> >
> >Last year in Bali, we saw charcoal briquettes being used for making
Satay.
> >Asking around, we didn't get very far until somebody suggested a look
into
> >a supermarket.
> >Yes, bags of briquettes, made somewhere in Surabaya.
> >Square cross section, 36 mm. a hole in the centre of about 10 mm and of
> >random length, clearly extruded.
> >Peter Verhaart
> >
> >
>

From crispin at NEWDAWN.SZ Thu Feb 27 00:34:39 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion - Paul
Message-ID: <THU.27.FEB.2003.073439.0200.CRISPIN@NEWDAWN.SZ>

Dear Paul

>I believe that the clarification will not come until we
>can have actual results from controlled experiments.
>Anyone doing such things, or planning to?

My question is how do we design an experiment that would resolve some of the
questions in a useful way. It wouldn't be good to have an experiment that
masked the truth to favour one viewpoint.

It seems to me that we should start the design of the task with a definition
of a stove that people want to own and will use by choice. If there are
stoves types being promoted that do not 'thrive' in the field because people
don't really want to use them or bother to learn how they work, it doesn't
mean they are not eligible to be studied. Lab stoves are useful at times
like this, but it would be nearly pointless to know how to made fuel burn in
a way that almost no one will imitate.

I admit to having some reservations about positioning and spacing the fuel
sticks as a method of controlling air flow, sticks which already having to
be fed manually every few minutes into the fire to maintain combustion. It
is just so much simpler to add a flat plate or hole here and there to make
some of that task more manageable.

Are we yet agreed on the problem description?

Paul, I am going to Pretoria tonight or tomorrow. When I get back I could
build a standard Rocket "L" with preheated secondary air on the back wall
only, with a sliding control door under the bottom of the L where the ash
accumulates to pick up heat from the ash+coals and the back wall. We can
place that in one of Scott's vermiculite filled boxes and try it in
Vereeniging.

What I am looking for is a reduced flame height with complete combustion. I
found the flames in the Eco Stove (with 2 pots and oven) hit the pot bottom
and chilled a great deal of the time, even though it didn't visibly smoke.

Other suggestions of things to look for?

Regards
Crispin punching cans

From ronallarson at QWEST.NET Thu Feb 27 10:01:36 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion - Paul
In-Reply-To: <005701c2de23$a75ff2e0$eedefea9@home>
Message-ID: <THU.27.FEB.2003.080136.0700.RONALLARSON@QWEST.NET>

Crispin:

You said (in reply to Paul Anderson):

>
>Other suggestions of things to look for?

(RWL): I would think a good (or the best?) test would be on your own
Vesto. You need to find ways to avoid your present preheating - presumably
by providing a new fast path for both primary and secondary air to the
inside. Also filling the present outer air heat exchange cavities with
various materials (clay, vermiculite, etc) will provide extra useful data.
Are these modifications possible?

I suppose tests with the same amount of fuel and testing for the maximum
water boiled away is the right test.

Ron

From psanders at ILSTU.EDU Thu Feb 27 10:12:30 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion - Paul
In-Reply-To: <005701c2de23$a75ff2e0$eedefea9@home>
Message-ID: <THU.27.FEB.2003.091230.0600.PSANDERS@ILSTU.EDU>

Crispin and all,

Experiments can be of at least two types:

1. "Idealized situations" to prove and give benchmarks for important
concepts, in this case the concept of pre-heated primary and/or secondary air.

2. "Real world" stoves to be tested for how well they can utilize the
concept in question.

We will need some of each.

> [Crispin wrote:] What I am looking for is a reduced flame height with
complete combustion.

The BEST example of that (that I have seen) in biomass stoves is Tom Reed's
WoodGas campstoves that have the small fan. FORCE in the air, and you can
keep the height of the flame very low. There is something to be learned in
this, such as
a. how to do it without a fan
b. cost savings on fuel and reduced/no chimney offset the cost of having
the fan
c. ?
d. ?

See you in Vereeniging.

Paul

At 07:34 AM 2/27/03 +0200, Crispin wrote:
>Dear Paul
>
> >I believe that the clarification will not come until we
> >can have actual results from controlled experiments.
> >Anyone doing such things, or planning to?
>
>My question is how do we design an experiment that would resolve some of the
>questions in a useful way. It wouldn't be good to have an experiment that
>masked the truth to favour one viewpoint.
>
>It seems to me that we should start the design of the task with a definition
>of a stove that people want to own and will use by choice. If there are
>stoves types being promoted that do not 'thrive' in the field because people
>don't really want to use them or bother to learn how they work, it doesn't
>mean they are not eligible to be studied. Lab stoves are useful at times
>like this, but it would be nearly pointless to know how to made fuel burn in
>a way that almost no one will imitate.
>
>I admit to having some reservations about positioning and spacing the fuel
>sticks as a method of controlling air flow, sticks which already having to
>be fed manually every few minutes into the fire to maintain combustion. It
>is just so much simpler to add a flat plate or hole here and there to make
>some of that task more manageable.
>
>Are we yet agreed on the problem description?
>
>Paul, I am going to Pretoria tonight or tomorrow. When I get back I could
>build a standard Rocket "L" with preheated secondary air on the back wall
>only, with a sliding control door under the bottom of the L where the ash
>accumulates to pick up heat from the ash+coals and the back wall. We can
>place that in one of Scott's vermiculite filled boxes and try it in
>Vereeniging.
>
>What I am looking for is a reduced flame height with complete combustion. I
>found the flames in the Eco Stove (with 2 pots and oven) hit the pot bottom
>and chilled a great deal of the time, even though it didn't visibly smoke.
>
>Other suggestions of things to look for?
>
>Regards
>Crispin punching cans

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From ronallarson at QWEST.NET Thu Feb 27 10:48:17 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:16 2004
Subject: Charcoal Briquetting Machinery
In-Reply-To: <18oGHO-0003Ia-00@ns2.wananchi.com>
Message-ID: <THU.27.FEB.2003.084817.0700.RONALLARSON@QWEST.NET>

Elsen:

I believe the key to a good burn will be a "holey" briquette. We do have
the extruded logs - but I think they are not likely to work for the resaons
you state. Definitely, softer woods are easier to work with that the more
dense also. (hmm - there must be an optimum density for different fuel wood
uses. I think a holey (maybe 19 holes) briquette of 10 to 15 cm diameter
and 2 or 3 cm thickness would be ideal. Then you stack up 1 to 5 for the
job at hand (being careful to align the holes).

Of course, the main point of all this is to save those valuable pyrolysis
gases which so often are vented and not flared.

Would your Indian briquetter work with sawdust - or only with char? I
think the right size and shape sawdust briquette would do as well as a holey
briquette.

Ron

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of elk
>Sent: Wednesday, February 26, 2003 10:11 PM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: Re: [STOVES] Charcoal Briquetting Machinery
>
>
>Ron;
>
>Be interesting to try the extruded biomass briquettes in a charcoal-making
>stove Ron. Can you get 'fuel logs' in Colorado? I suspect that the
>burn rate
>would be slower due to the briquettes relatively high density (compared to
>wood). Do you think that this would be an advantage or impediment? The size
>& shape- length, in particular- should be appropriate for the vertical fuel
>load.
>
>elk
>
>
>--------------------------
>Elsen L. Karstad
>elk@wananchi.com
>www.chardust.com
>Nairobi Kenya
>
>
>
>----- Original Message -----
>From: "Ron Larson" <ronallarson@QWEST.NET>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Thursday, February 27, 2003 4:01 AM
>Subject: Re: [STOVES] Charcoal Briquetting Machinery
>
>
>> Elsen, Piet, et al
>>
>> I sure would like to know the cost of these extruded sawdust
>briquettes
>> before and after charcoaling. A charcoal-making stove owner ought to be
>> quite willing to take them as sawdust and return a charcoaled briquette -
>at
>> no cost. Everyone wins - even we in the US if the alternative
>large scale
>> approach puts a lot of global warming gases (CO, CH4, etc) into the
>> atmosphere. The transaction costs won't allow this for each individual -
>> but a village organization should be possible for the differential cost
>> between the raw and charcoaled prices.
>>
>> Ron
>>
>>
>>
>> >-----Original Message-----
>> >From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>> >Behalf Of Peter Verhaart
>> >Sent: Wednesday, February 26, 2003 4:26 PM
>> >To: STOVES@LISTSERV.REPP.ORG
>> >Subject: Re: [STOVES] Charcoal Briquetting Machinery
>> >
>> >
>> >At 13:59 26/02/03 +0300, you wrote:
>> >>Hello Musungu;
>> >>
>> >>On 17th Feb. you wrote:
>> >>
>> >Chop
>> >
>> >
>> >>Though we didn't see any, they also claim to make a high pressure
>biomass
>> >>extruder that is used in Malaysia or Indonesia where dried sawdust is
>> >>extruded and subsequently carbonised for sale to customers in
>> >Hong Kong and
>> >>Japan.
>> >
>> >
>> >Last year in Bali, we saw charcoal briquettes being used for making
>Satay.
>> >Asking around, we didn't get very far until somebody suggested a look
>into
>> >a supermarket.
>> >Yes, bags of briquettes, made somewhere in Surabaya.
>> >Square cross section, 36 mm. a hole in the centre of about 10 mm and of
>> >random length, clearly extruded.
>> >Peter Verhaart
>> >
>> >
>>
>
>

From cree at DOWCO.COM Thu Feb 27 12:48:08 2003
From: cree at DOWCO.COM (JOHN OLSEN)
Date: Tue Aug 10 18:30:16 2004
Subject: "Holey" briquettes, extruded densified Biomass
Message-ID: <THU.27.FEB.2003.094808.0800.CREE@DOWCO.COM>

We are now making them in Canada, at a 17 acre chip mill site, in
Chilliwack, B.C.
regards
JohnO
www.heatloginc.com

From dstill at EPUD.NET Wed Feb 19 20:45:25 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion
Message-ID: <WED.19.FEB.2003.174525.0800.DSTILL@EPUD.NET>

Dear Friends,

With unabated good humor I will attempt a last time to define what I see as
a very interesting difference used in successful stoves. Thanks again to Ron
for bringing up this topic which to my mind has solidified around the
subjects of: 1.) controlling primary air and 2.) benefits of preheated
secondary air.

In the Rocket combustion chamber (that is designed to assist the burning of
all metered fuel initially) the only control over primary air is that the
opening to the fuel magazine is small: about 20 square inches. Tom Reed and
others think that an adjustable control of primary air would be a good thing
so that a correct amount of air accompanies the burning of various amounts
of fuel.

Ron is wondering if adding preheated secondary air would improve combustion.

In batch loading stoves both control of primary air and adding preheated
secondary air are essential parts of a different system of burning. Reducing
primary air controls the speed of burning and then adding preheated
secondary air assists secondary burn.

Crispin suggests that these two additions would improve the Rocket stove. I
respond that while they might, and it certainly will be one of the things we
test, control of rate of combustion in a Rocket stove is determined by the
rate of fuel feed and not by choking off primary air. The two types of
stoves follow very different strategies towards the goal of clean
combustion.

This summer, Ron Larson, Paul Anderson, perhaps Tom Reed, in a friendly,
supportive atmosphere of Socratic learning, will join Larry Winiarski, Dale
Andreatta, perhaps Tami Bond, Damon Ogle and many others to share a common
experience of looking at these two patterns of burning and analyzing their
benefits. Can't wait!

All Best,

Dean

From elk at WANANCHI.COM Thu Feb 27 23:59:01 2003
From: elk at WANANCHI.COM (elk)
Date: Tue Aug 10 18:30:16 2004
Subject: Charcoal Briquetting Machinery
Message-ID: <FRI.28.FEB.2003.075901.0300.ELK@WANANCHI.COM>

Hi Ron;

Intuitively, I think the lengthier 'holey' fuel log would be most
appropriate for use in charcoal making stoves.

We have ordered the roller-type of briquetter, which makes 35 gm
pillow-shaped briquettes from char powder- vendor's waste in our case. As
far as I know, this type of machine cannot process sawdust or any type of
uncarbonised biomass. You need a very high pressure ram or screw extruder to
effectively melt cellulose and 'glue' particles together into pellets,
briquettes or fuel logs.

From pverhaart at OPTUSNET.COM.AU Fri Feb 28 05:16:16 2003
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:16 2004
Subject: Combustion
In-Reply-To: <001301c2d881$d1fb8de0$d01e6c0c@default>
Message-ID: <FRI.28.FEB.2003.201616.1000.PVERHAART@OPTUSNET.COM.AU>

Dear Dean and fellow Stovers,

The metering of primary and secondary air will always depend on
the amount of fuel that is actually taking part in the burning.
However, there is another aspect, mentioned by some, mixing.
If the airflow is decreased, the air velocity in and around the fire will
decrease and this has a profound influence on the mixing. This unless
measures are taken to keep the volocity constant. I haven't heard of a
stove with this provision.
It is borh the Rocket and the Downdraft stove who show clean combustion. In
both the structure of the fuelbed determine the flow pattern of the air in
the fire zone and the quality of combustion depends on relatively high
velocities both for mixing as well as for an intense char combustion.
In both types of stove control of the heat output rate is not
straightforward. Both need a critical mass of burning fuel to continue
burning. The airflow will mostly be roughly constant eg when the fire is
tempered much more excess air is drawn in but at least the combustion
remains clean.
In my Downdraft BBQ the rate of combustion is controlled by varying the
active grate surface area, a slide covers part of it.
In the Rocket stove something similar might be possible. What we have to
watch out for is reducing the air velocity in critical locations.

My pennyworth.

Kind regards,

Piet

At 17:45 19/02/03 -0800, you wrote:
>Dear Friends,
>
>With unabated good humor I will attempt a last time to define what I see as
>a very interesting difference used in successful stoves. Thanks again to Ron
>for bringing up this topic which to my mind has solidified around the
>subjects of: 1.) controlling primary air and 2.) benefits of preheated
>secondary air.
Chop.

From kchisholm at CA.INTER.NET Fri Feb 28 05:23:59 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:16 2004
Subject: Is it Good to be Holey?? Re: [STOVES] Charcoal Briquetting
Machinery
Message-ID: <FRI.28.FEB.2003.062359.0400.KCHISHOLM@CA.INTER.NET>

Dear List

Conventional wisdom says that holey briquettes of uncarbonized biomass are
"better" than holey briquettes of the same material that is not holey.

I haven't used holey briquettes, and haven't seen any specific Test Reports
to know the actual test conditions, but it is intuitive to me that dry
briquettes should burn basically the same, holes or not.

The reason for this feeling is that generally, briquettes are a generally a
"dry" fuel, with large surface area, and even greater surface area is, I
feel, not an advantage to combustion.

If there are differences in performances between holey and unholey
briquettes, I would suggest that this is because factors other than an
incremental increase in the fuel surface area were at play.

The problem with dry biomass is that it is very easy to gasify and very
difficult to burn to completion. Dry wood is a radically different fuel from
wet wood. One can make a case that contrary to making briquettes with more
surface area, one should be making briquettes with a combustion retardant,
to slow the primary combustion process to the point that the secondary
combustion process has a fighting chance of being brought to completion.

I have some questions as follows:

1: Under what conditions is it good to be holey?
2: Where conditions are such that an increase in fuel surface area are
advantageous, is there a better way to address these conditions than by
making briquettes with holes?

Kindest regards,

Kevin

----- Original Message -----
From: "elk" <elk@WANANCHI.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, February 28, 2003 12:59 AM
Subject: Re: [STOVES] Charcoal Briquetting Machinery

> Hi Ron;
>
> Intuitively, I think the lengthier 'holey' fuel log would be most
> appropriate for use in charcoal making stoves.
>
> We have ordered the roller-type of briquetter, which makes 35 gm
> pillow-shaped briquettes from char powder- vendor's waste in our case. As
> far as I know, this type of machine cannot process sawdust or any type of
> uncarbonised biomass. You need a very high pressure ram or screw extruder
to
> effectively melt cellulose and 'glue' particles together into pellets,
> briquettes or fuel logs.
>
> From my experience, the biomass briquettes- in whatever shape- should be
> denser that the original material it is derived from. Reduce the heat &
> pressures and hence final product density too much & the briquette will
fall
> apart & expand on burning- which is characterised by much smoke and little
> flame. There are not many applications for this type of fuel.
>
...del...

From cree at DOWCO.COM Fri Feb 28 10:27:08 2003
From: cree at DOWCO.COM (JOHN OLSEN)
Date: Tue Aug 10 18:30:16 2004
Subject: Is it Good to be Holey?? Re: [STOVES] Charcoal Briquetting
Machinery
In-Reply-To: <001601c2df13$f1c753a0$819a0a40@kevin>
Message-ID: <FRI.28.FEB.2003.072708.0800.CREE@DOWCO.COM>

Kevin wrote,,

,,,,,The problem with dry biomass is that it is very easy to gasify and very
difficult to burn to completion,,,,
I disagree, if the biomass is dried, as in our process to 8% moisture
content, we achieve total burn.

,,,,Under what conditions is it good to be holey?,,,,
A single hole we have found is optimum and produces a high BTU radiant heat.

,,,, Where conditions are such that an increase in fuel surface area are
advantageous, is there a better way to address these conditions than by
making briquettes with holes?,,,
The "simple is better" tradition seems to apply here.

John Olsen

From rstanley at LEGACYFOUND.ORG Fri Feb 28 16:49:09 2003
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:16 2004
Subject: Is it Good to be Holey?? Re: [STOVES] Charcoal Briquetting
Machinery
Message-ID: <SAT.1.MAR.2003.004909.0300.>

The hole has certain very specific advantages or no advantages at all:
The hole in the vertically aligned burnign briquette provides
1) a draft
2) an insulated combustion chamber similar to Dean & Larry's rocket
principles
which means far faster ignition and less smoke "getting to temperature"
3) a far more rapid drying product (this applies obviously only to the wet low
pressure ambient temp process.

Mass per mass, holey briquetes will far out preform wood or charcoal in a rural
or urban poor family cooking environment, where the local family stove is un
insulated or simply three stones, using only two or three briquettes at a
time. Put them in an improved stove of most any kind and their preformance,
while still improved, is no where near as improved as that of wood. The ~6%
loss in volume/mass due to the 2.5 cm dia center hole of our standard 10 cm dia
x 7.5 cm tall briquette is more or less insignificant when compared to the
advanteges mentioned above. You can't do much more with the holey briquette as
it stands . You can do a lot more to improve the burning efficiency of wood

We are observing use of 2 to 2.5, of the 125 gram holey briquetes is
sufficient to replace 1.2 kg of fuel wood in the above domestic basic cooking
situation. This is based on a field observations in the same areas by the same
populations at the same times in east and central Africa over the past 9 years.
In the upper Andees where the fuelwood consumption figures are 3 to 4 kg per
person per day the briquette consumption increases proportionately to between 4
and 6 a day, same population same time of year as obsedrved over the past two
years. The open burning wood is commonly quoted to be between 6 and 10 %
efficient. Two briquettes weighing in at a total of 250 grams with 75% the
calorific value of wood obviously have to be preforming at far greater
efficiency. As deducted by simple comparison of the given values, (viz 1.2 kg
wood @ 8% = 250 grams of holey briquette @ X efficiency), the holey briquette
in the open burn situation would seem to be about 38% efficient. We have not
yet done absolute tests of heat values but have published comparative tests
between wood charcoal and the holey briquettes in hte american chemical
societies' Journal of chemical innovation. (Feb 2001). The link is
http://pubs.acs.org/subscribe/journals/ci/31/i02/toc/toc_i02.html
which gets you to our cover article titled "A Unique Approach to Conservation"

The other advantage to the hole is seen in accelerating the drying the
briquette. The above briquette comes out of the mold of the basic hand press at
about 500 grams. It dries unassisted, under ambient conditions in the tropics
and temperate latitudes (ex winter season) in 4 to 5 days, down to 120 to 140
grams. A solid briquette of same blend same porosity and permeability without
the hole will take about 75 to 100 percent longer to dry . This amounts to a
lot of space for the micro entrepreneur, working as they often do, out of their
doorstep. While the center hole only increases surface area by about 10%, it
has the effect of creating a slight draft and an exposure just where the
briquette moisture is most entrapped, in the center of the cylinder. Sure other
than one center hole can be used star shapes or the chinese multiport holes as
well but for us the basic engineering "KISS" principle (keep it simple stupid)
applies best.

As to heat and pressure processes, this is One most widely recognised form of
briquette making and surely as noted the lower pressure and lower temperature
would have q negative effec on the integrity of the briquette as both contibute
to its binding strength. In the wet process however we are relying upon the
random alignment of natural fibers to do that job in a water slurry. We use 150
to 225 psi ambient temperature higher press ure and we generate heat which
would tend to destropy the fibers. We start with a water slurry and wind up
with a product which is between .25 and .4 grams per cc. Density is important
but more important is the hardness and strength of the briquette. The whole
trick with these briquettes is in knowing when to the biomass has decomposed
sufficiently without creating a briquete which will be too spongy or too muddy
. Its a different process entirely than the high pressure high temperature
approach. Still one does not want a loose or even too tight a cake as either
gives nothing much more than smoke.

For many stovers who want to test , or have tested holey briquettes in their
various improved stoves, I hope this clarifies a few issues raised.

wholey yours,
Richard Stanley

From kchisholm at CA.INTER.NET Fri Feb 28 11:42:42 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:16 2004
Subject: Is it Good to be Holey?? Re: [STOVES] Charcoal Briquetting
Machinery
Message-ID: <FRI.28.FEB.2003.124242.0400.KCHISHOLM@CA.INTER.NET>

Dear John
----- Original Message -----
From: "JOHN OLSEN" <cree@dowco.com>
To: "Kevin Chisholm" <kchisholm@ca.inter.net>; <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, February 28, 2003 11:27 AM
Subject: RE: [STOVES] Is it Good to be Holey?? Re: [STOVES] Charcoal
Briquetting Machinery

>
> Kevin wrote,,
>
> ,,,,,The problem with dry biomass is that it is very easy to gasify and
very
> difficult to burn to completion,,,,
> I disagree, if the biomass is dried, as in our process to 8% moisture
> content, we achieve total burn.

??? Where do we disagree? I am saying that dry biomass is easy to burn and
you are saying that dry biomass is easy to burn.
>
> ,,,,Under what conditions is it good to be holey?,,,,
> A single hole we have found is optimum and produces a high BTU radiant
heat.

1: What parameters did you consider in your testing, to arrive t the
conclusion that a one hole briquette was optimal?
2: Could you please explain what you mean by "high BTU Radiant Heat?"
3: Will "no hole" or "multi hole" briquettes produce results that are better
or worse for your situation?
>
> ,,,, Where conditions are such that an increase in fuel surface area are
> advantageous, is there a better way to address these conditions than by
> making briquettes with holes?,,,
> The "simple is better" tradition seems to apply here.
>
But it doesn't!! It is simpler to make briquettes with no holes. It is
simpler still to use adequately dry fuel of the right size.

Kindest regards,

Kevin

> John Olsen
>
>
>

From ronallarson at QWEST.NET Fri Feb 28 23:57:43 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:16 2004
Subject: FW: [STOVES] Combustion, shape of sticks - Sjoerd
Message-ID: <FRI.28.FEB.2003.215743.0700.RONALLARSON@QWEST.NET>

Stovers: I am quite sure that Ray Wijewardene will not mind my
passing this on to the full stoves. Ray speaks from authority on these
matters.

Ray: 1. I have a dictionary with > 2000 pages, but nothing there
between secant and secco. I presume that secateurs are big two bladed
"snips". Why are these used rather than machetes? Is it mainly to cut
longer branches or stems into the short sections of25 MM?

2. We have not heard from Sri Lanka on your "wood-gas"
stove development in some time. What is the price now and sales history?
Consumer satisfaction?

3. I don't understand "down-flow". By this do you mean the
downward propagating pyrolysis zone? Have you a means of automatic feeding
of fuel?

4. Are you now working with C-4 plants and can you
recommend any specific species yet? I can't remember world record yields
but think you are proposing something exceptionally good. Can you convert
this into an efficiency number? When you convert this into local
produduction at local labor and land rates - what price per kilo for "dry"
material?

Thanks so much for this addition to the question of saws vs ?? (and on
several other tantalizing pieces of information.

Ron

> -----Original Message-----
> From: Ray Wijewardene [mailto:raywije@eureka.lk]
> Sent: Friday, February 28, 2003 7:07 AM
> To: Ron Larson
> Subject: RE: [STOVES] Combustion, shape of sticks - Sjoerd
>
> Our experience from the 'real world' (the under-developed world, if you
> like) is towards the most sustainable way of growing that fuel-wood. Our
> 'druthers' now are for coppicing of wood diameters no larger than 25 to
> 50 mm ( 2 inches...at the most) in diameter. Should anything larger be
> coming to the gasifier or stove...(it would mean that the tree itself was
> being cut down, and that would truly horrrify us!) We now coppice-harvest
> only the (1" to 2" ) branches ... while leaving the smaller branches to
> mature in a few months. As for length we find the 100 mm long 'chunks'
> handle best (both for flow-through the gasifier as well as for convenience
> of transport from field to burner/gasifier/ whatever.... and also for
> quick drying in the field even in a hot-humid climate. The 25mm diameter
> chunks also work fine in our wood-gas stoves but lengths are reduced to 25
> cm for eas of 'down-flow' through the stove.
>
> Here we are also looking for convenience in manual harvesting as the 25-50
> mm branches are the largest that can conveniently be lopped with
> long-handled secateurs... In the tropics (year-round sunshine) we are
> looking at harvests of the coppices at 2 to 3 to 4 times a year depending
> on rainfall. We are looking at harvests of the coppices between 20-40
> tonnes per hectare per year on a continuous basis.. with prospects for
> VERY much higher (two to three times!) yields if our trials with C-4
> plants work out. Here we are happy to go along with the advice and
> guidance from Dr AD in Pune.
>
> Ray Wijewardene.
>
>