January 2004 Gasification Archive

For more information to help people develop better stoves for cooking with biomass fuels in developing regions, please see our web site: http://www.bioenergylists.org

From Gavin at AA3GENERGI.FORCE9.CO.UK Thu Jan 1 12:57:13 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <1a96vv4i30fkf6s0019evqhu48kkgo16fs@4ax.com>
Message-ID: <THU.1.JAN.2004.175713.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

I kept my skirt off! However all the best to you too for '04 interesting
times ahead for biomass in the UK?

My little gasifier needs to reach 600(C to become stable and self supporting
with a stable flame in the offgas. Does this bear any relationship to the
thread? I doubt it!!

I have seen AJH burner in the flesh as it were- it's a roaring beast!
HNY
Gavin

[GGG] <snip>

From andrew.heggie at DTN.NTL.COM Thu Jan 1 16:17:22 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <MABBJLGAAFJBOBCKKPMGIEHGDDAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <THU.1.JAN.2004.211722.0000.>

On Thu, 1 Jan 2004 17:57:13 -0000, Gavin Gulliver-Goodall wrote:

>I kept my skirt off! However all the best to you too for '04 interesting
>times ahead for biomass in the UK?

Is that in the Chinese sense of "may you live in interesting times"?
My hatches are already battened down tight and I have to try to get
myself gainfully occupied this year.
>
>My little gasifier needs to reach 600(C to become stable and self supporting
>with a stable flame in the offgas. Does this bear any relationship to the
>thread? I doubt it!!

Maybe, because it suggests the flame is not supported at less, were
there a constant ignition source (gas pilot light for instance) would
it support a flame at lower temperature?

AJH

From Gavin at AA3GENERGI.FORCE9.CO.UK Thu Jan 1 18:32:53 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <9239vvkn1420813t9dll1j2d9irjd5r6cl@4ax.com>
Message-ID: <THU.1.JAN.2004.233253.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

<snip>>My little gasifier needs to reach 600(C to become stable and self
supporting
>with a stable flame in the offgas. Does this bear any relationship to the
>thread? I doubt it!!

Maybe, because it suggests the flame is not supported at less, were
there a constant ignition source (gas pilot light for instance) would
it support a flame at lower temperature?
[GGG] no idea it is in a heap in the garden although two of its successors
are in slightly better preserved status I doubt that we would get permission
to play with them in situ again so would have to remove and rebuild at great
expense. So I d suggest sticking with otehrpeoples proven technology.;-)
GGG

AJH

From lanny at ROMAN.NET Thu Jan 1 19:26:46 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:47 2004
Subject: The Henson BMHB Stove
Message-ID: <THU.1.JAN.2004.192646.0500.LANNY@ROMAN.NET>

Dear Stove Friends,
My new Two Pot Bain Marie With Oven Heart Burner Stove has 3 new features.
It uses two very efficient Bain Marie pots. It has a new low profile Heart
Burner. This burner is almost good but needs more work, and it has new, way
good, no weld, simple oven door hinges and catches.
It took 1000 grams of wood to cook 8 lb. 3.62 KG, 100 servings of pinto
beans (the package said a serving is 1/4 cup dry, 36 gr dry, 60 calories).
It takes 2 hours to cook soaked pinto beans but the stove stayed hot for.
That is 10 grams of wood per serving.
A 19.9kb photo http://www.lanny.us/bmhb1.jpg
More photos and details later.
Lanny Henson

From das at EAGLE-ACCESS.NET Fri Jan 2 16:29:32 2004
From: das at EAGLE-ACCESS.NET (Das)
Date: Tue Aug 10 18:30:47 2004
Subject: Chimneys
Message-ID: <FRI.2.JAN.2004.142932.0700.DAS@EAGLEACCESS.NET>

A recent Stovers posting made the most sound argument for flue pipe.
It gets the smoke and fumes of failure modes out of your living space.
As you have seen, I have put a flue on everything that I have here.

An aditional goal of improved combustion is to increase the fraction of the
operating time with secondary combustion lightoff. Ideally we aim to
eliminate all release of uncombusted gases. Small grain fuels sugh as
chips offer much more steady gas quality and combustion quality.

Larger fuel such as Cord wood goes through drastic cycles with fresh fuel
extinguishing secondary burn, then excessive heat output, then char burn,
then repeat the cycle.

You are doing good work. It is an hoonor to work with you.

A. Das
Original Sources/Biomass Energy Foundation
Box 7137, Boulder, CO 80306
das@eagle-access.net

----------
> From: Dean Still <dstill@EPUD.NET>
> To: STOVES@LISTSERV.REPP.ORG
> Subject: Re: [STOVES] Chimneys
> Date: Tuesday, December 16, 2003 12:37 AM
>
> Dear Alex,
>
> Our intention at Aprovecho is always to share all information and we hope
> that beginning this winter we can generate some accurate numbers for
various
> stoves. We received the $8,000 Enerac 3000E today! Should give us good
> readings of CO, CO2, O2, hydrocarbons...Thanks to the Murdock
Foundation...
>
> I look at chimneys in a very positive light because the cost is low and
the
> cure to indoor air pollution, for all practical purposes, complete. Here
in
> Oregon, we heat with wood, many folks use wood stoves as their only
heating
> source. Chimneys here need to be cleaned often, more often if the stove
> burns badly as most do, some monthly. It is important to make the chimney
> easy to clean. The metal chimney in my house is twenty years old. The 55
> gallon barrel stove that heats our lab is more than twenty years old.
> Chimneys are the answer to IAP; the only question is how to fund their
> installation.
>
> The best combustion chamber can be easily defeated by operator error.
> Although fans and 1,000F preheated primary air are much harder to defeat
> than stoves relying on natural draft. I love blast furnace heating stoves
> coupled to big heat exchangers! But simple cooking stoves without fans
are
> usually stuffed full of too much fuel, green as an apple. A chimney
guards
> the operator from their actions. Just have to clean it once in a while.
Buy
> good stuff...
>
> Larry wants us to make light weight chimneys out of ceramic. Ken Goyer
> extruded a beauty a while back...
>
> All Best,
>
> Dean

From Kanchan at KU.EDU.NP Sat Jan 3 10:05:19 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
Message-ID: <SAT.3.JAN.2004.205019.0545.KANCHAN@KU.EDU.NP>

Hello everybody
My name is Kanchan Rai. I am a research assistant at Research, Development
and Consultancy Unit in Kathmandu University in Nepal (I have Completed
Mechanical Engineering in 2002 from same university). I am working on
Development of an Improved Cooking Stoves in the Mountain Areas of Nepal.
At the same time I am also working on Waste management project in the
university. I am working on paper briquettes and thermal insulating bricks
(composed of paper, plastics, glass powder and some additional materials)
from waste materials.

I am a regular receiver of emails of stove discussion. This is my first
time writing on discussion lists.

There have been lots of discussion regarding EXCESS AIR last week. I like
to add my view on that though I am not specialist on combustion. I am just
a begineer.

What is stoichiometric air? Is this sufficient?
This is the theoritical amount of air required to burn the fuel
completely. For e.g. 1 kg of pinewood ( C 44.45%, O 33.96 %, H 5.93%, H2O
15 %, Ash 0.3% w.b.),(Relative humidity 40% ), needs 5.71 kg of air to
burn completely. Theoritically at this amount of air fuel produced maximum
of its energy but it practice it is not so.

The sad thing is all air entering the combustion chamber donot
participates in reaction. This greatly depends upon the stove design and
fuel loading pattern. Hence we need some more air to complete combustion
and the air is called EXCESS AIR. In small scale biomass combustion
applications, it is necessary to have excess air ratio well above one,
usually 1.5, to ensure a sufficient mixing of inlet air and fuel gas.

DOES EXCESS AIR ALWAYS HELPS COMBUSTION ?

OFCOURSE NOT, if excess air is very much it reduces the combustion
temperature. BUT HOw!!

Air is composed of 21 % oxygen and 79 % nitrogen (other gases are such as
Ar, CO2, H2, Xe, Kr etc but comparably neglegible), on which only oxgen
takes part in combustion. Only less than one third of air is useful for
combustion. Nitrogen, inspite of helping, absorbing energy from the
combustion zone, resulting lower combustion temperature and dilution which
effects on the reaction of oxygen and volatile matters. if 1 kg of
pinewood is burned with stoichiometric air only 1.2 kg of oxygen takes
parts in reaction and remaining 4.5 kg of Nitrogen absorbs energy from
combustion zone.

For 150 % excess air to burn 1 kg of firewood requires 14.3 kg of air, in
which only 2.98 kg of oxygen takes part in reaction. THINK!!!! what does
the remaining 11.32 kg Nitrogen contributes for the combustion (only
negative effect).
The specific heat of Oxygen and nitrogen is 0.795 kJ/kg and 1.04 kJ/kg
respectively. It is known that to burn out CO, CH4 we need preheated air
above 600 C. Assuming air is entering at room temp (no prehaeating) let 20
C. Nitrogen (11.32 kg) requires 6828 kJ of energy, when air is heated from
20 C to 600 C) and O2 (2.98 kg) requires 1375 kJ/kg of energy. The heating
value of pinewood with 15 % moisture is 17.6 MJ/kg. Hence heating air (20
C - 600C) consumes 46 % of fuel energy, and increase with increase in
excess air. Hence to much excess is always harmful for clean combustion.

Calcultions are based on Excel sheet of Combustion Analysis, developed by
myself and it works fine in my case.

Happy new year 2004 to all the stovers'.

kanchan

From dstill at EPUD.NET Sat Jan 3 03:07:24 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <27079.202.79.62.12.1073142319.squirrel@www.webmail.ku.edu.np>
Message-ID: <SAT.3.JAN.2004.000724.0800.DSTILL@EPUD.NET>

Dear Kanchan,

Thanks very much for your helpful contribution to the discussion of excess
air. Determining the amount of air flowing through the stove can be
difficult to determine. Measuring the flow can disturb it.

Damon Ogle at Aprovecho has discussed with me that measuring temperature, on
the other hand, is relatively simple. Raising the temperatures in the
combustion chamber and below the pot can indicate improved combustion.

The characteristics in the combustion chamber that have elevated
temperatures in our experiments are: 1.) Blocking air coming in on top of
the fuel raises temperatures about 50 to 75 C. 2.) Having primary air come
up through the burning coals elevates temperatures about twice that much 3.)
Creating friction above the fire, making a "permanent damper" in the post
combustion chamber spaces so that only a controlled amount of air enters the
combustion chamber seems promising 4.) Using really good insulation so that
the least amount of heat is diverted from the fire seems very important. 5.)
Using a 1.) long horizontal feed magazine or 2.) a downdraft/downfeed feed
magazine or 3.) a batch loader has the advantage that primary air can be
preheated. Preheating primary air is accomplished in all three cases by
removing the fire from easy sight. 6.) I don't know of any way to preheat
primary air in a side feed type stove without using a fan. But using a fan
certainly gets rid of smoke even when temperatures drop!

Normal temperatures in an insulated Rocket type combustion chamber are
around 850C but applications of these methods can raise temperatures to
around 1100 C.

All Best,

Dean

From crispin at NEWDAWN.SZ Sat Jan 3 08:19:13 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
Message-ID: <SAT.3.JAN.2004.081913.0500.CRISPIN@NEWDAWN.SZ>

Dear Kanchan

Your analysis looks very good to me, but like you I am not a 'specialist'
and in fact often list myself as a 'generalist' which you can think of
writing as a fraction: 1 divided by 'specialist'.

I contributed very little to that discussion other than to point out that
preheating the makes your equation change, and very favourably.

If you could add a couple cells into your spreadsheet in which you entered
the amount of pre-heating that the primary and (if you have it) secondary
air you will be quite surprised at the difference made to the heat output.

The trick is to get heat that would normally be lost from the stove and
chimney into the fire. There are lots of ways to do it so there remain many
still-unexplored avenues for stove layout.

For example, it you manage to get 1/2 the energy required for heating up the
'useless' parts of the air (to 300 of the needed 600 deg C) then instead of
46% of the fuel being use for that purpose, only 23 % would be used, and the
efficiency of the entire stove would be correspondingly higher - a LOT
higher because previously wasted heat is now being used to support
combustion deep inside.

In real life there are rainy days and the extra humidity in the air plays a
significant role in reducing fire temperatures. Preheating the air adds
heat to the airborne moisture and this heat is 'available' in the whole
equation. The presence of steam is of course going to interfere with
combustion but the principle remains: preheated 600 deg moist air has a lot
of energy in it and it is available to help support combustion as well as
being transferable (in some measure) to the pot.

Perhaps you can get the 'same heat' to pass by a pot several times. If you
were wondering whether or not you would get more total heat transferred to a
pot by passing the hot gasses past it many times or only once, there is a
paper by physicist Prof Bernhard Scheffler of the University of Pretoria
which he presented to the Solar '82 conference which many be relevant. He
showed conclusively that the highest total heat transferred from a solar
collecter to a hot water tank occurs when the all the water in the tank
passes through the collector exactly once during the heating cycle (perhaps
8 hours). To my knowledge it was the first mathematical proof of this, and
answered a long standing question about whether or not one got more heat by
speeding the water through a solar collector many times a day (or not) which
was a hot topic in the '70's.

He can be contacted at schefflr@postino.up.ac.za

Heat transfer is complicated and hot gas to cold pot transfer is also wide
open to experimentation. I am not sure if anyone has done much in the field
of heat recycling theory.

I would like to have a look at your spreadsheet to see if I can learn from
it. I have one to offer in return which calculates the draft produced (in
pascals) in various portions of a stove based on layout, air, gas and
reaction products and lab measurements (temperatures). It is primitive but
it is useful for predicting velocities in various places (up to 8 places).

Regards
Crispin

----- Original Message -----
From: "Kanchan Rai" <Kanchan@KU.EDU.NP>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, January 03, 2004 10:05 AM
Subject: [STOVES] AJH: excess air

I am a regular receiver of emails of stove discussion. This is my first
time writing on discussion lists.

There have been lots of discussion regarding EXCESS AIR last week. I like
to add my view on that though I am not specialist on combustion. I am just
a begineer.

DOES EXCESS AIR ALWAYS HELPS COMBUSTION ?

OFCOURSE NOT, if excess air is very much it reduces the combustion
temperature. BUT HOw!!

Calcultions are based on Excel sheet of Combustion Analysis, developed by
myself and it works fine in my case.

Happy new year 2004 to all the stovers'.

kanchan

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From lanny at ROMAN.NET Sat Jan 3 11:03:07 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:47 2004
Subject: The Henson BMHB Stove
Message-ID: <SAT.3.JAN.2004.110307.0500.LANNY@ROMAN.NET>

http://www.lanny.us/bmhb1.html about 100kb

Stove Friends,
I am very pleased with my new cook stove. After bringing 2-8QT pots to a
boil I shut down the stove and the retained heat continued to cook and will
hold safe temps (160 degF) for 5.5 hours!
The Henson BMHB1 has 4 new features: a low profile heart burner design;
simple to fab oven door hinge and catch; 2 very efficient and practical Bain
Marie pots, and improved heat retention.

BMHB test #1
I am still learning the best way to use the stove but I did a test on the
third firing. It took 1000 grams of wood to cook 8 lb. 3.62 KG, 100 servings
of dry pinto beans. (the package said a serving is 1/4 cup dry, 36 gr dry,
and 60 calories). That is 10 grams of wood per serving.

It takes 2 hours to cook soaked pinto beans but the pots stayed hot for 5.5
hours. After the pots came to a boil I shut down the stove (closed the air
intakes and capped the exhaust) and the pots boiled over for 25 min as the
internal temps inside the stove equalized. The pots continued to boil for
over an hour. At 2.5 hours the pot temps were 200 degF and at 5.5 hours the
pot temps were 160 degF. Next time I will shut the stove at 200 degF to see
if the retained heat will bring the pots to a boil.

A clean burning low profile burner would be handy to shorten the height of a
stove body and I am confident that it can be done but the Heart Burner did
not perform as well as the Rocket Burner at the low power. I was using low
power in this test (1000 grams of wood per hour). The exhaust was mostly
clear but did not smell right. I could see a little smoke occasionally and
the burner did turn red hot at low power. Next test I will try a faster
burn.

Please check the web page weekly for more details.
http://www.lanny.us/bmhb1.html

Lanny Henson

From ronallarson at QWEST.NET Sat Jan 3 11:30:26 2004
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:47 2004
Subject: Modeling Efforts
Message-ID: <SAT.3.JAN.2004.093026.0700.RONALLARSON@QWEST.NET>

Crispin:

1. Thanks very much for several great observations.

2. This is the first time I have heard of your modeling efforts - which
sounds like it may be available to our list. If so, I'd certainly like to
have a copy. Nothing to offer in return, but I am willing to work to
validate and extend yours and anyone's.

3. I won't respond separately to a nice message about 5 hours
before yours from Dean Still (reporting also for Damon Ogle) on the
measurement of (and especially ways to increase) temperature . I wonder if
your model can duplicate the various temperature improvements that they
found from controlling air. I think all of the ideas they suggested are
worth extensive additional work. I am most anxious to see if yours or any
model can duplicate the quantitative results they have reported.

4. I have started some similar ideas with Agua Das - and will report
soon on those. Much along the lines of Dean and Damon, but also with
preheat. No modeling behind any of this yet - but I sure would like to do
so.

Kanchan:

1. Like Crispin, I am impressed by your report and would like to
similarly request a copy of your spread sheet. Thanks for your
contribution.

Dale Andreatta (who I have seen doing the best prior modeling work):

1. I hope you will jump in on what you have and know to be available.

All stovers:

1. I hope anyone else having (or knowing of) any modeling spreadsheets
and/or programs will report on their availability and any successes they
have had with them.

Tom Miles:

1. Can you tell us the limits on "stoves" ability to handle a "library"
of such computer software.

Ron

----- Original Message -----
From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, January 03, 2004 6:19 AM
Subject: RE :AJH: excess air

> ---------------------- Information from the mail
header -----------------------
> Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
> Poster: Crispin Pemberton-Pigott <crispin@NEWDAWN.SZ>
> Subject: RE :AJH: excess air
> --------------------------------------------------------------------------
-----
>
> Dear Kanchan
>
<snip>

From ronallarson at QWEST.NET Sat Jan 3 11:46:10 2004
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:47 2004
Subject: The Henson BMHB Stove
Message-ID: <SAT.3.JAN.2004.094610.0700.RONALLARSON@QWEST.NET>

Lanny:

1. Congratulations on the results you just sent in. I wonder if we have a
record like yours - but you are using a very small amount of wood!

2. I'm glad I went to your site - I wasn't expecting to see the Bain Marie
pots inside an oven! Obviously a very efficient "Hay Box". Was the picture
you gave shown with a Rocket Burner?

3. I don't recall your describing what you mean by a Heart Burner. Could
you give a citation on "stoves" or your site - or tell us more.

Thansk in advance.

Ron

----- Original Message -----
From: Lanny Henson <lanny@ROMAN.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, January 03, 2004 9:03 AM
Subject: Re: The Henson BMHB Stove

> ---------------------- Information from the mail
header -----------------------
> Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
> Poster: Lanny Henson <lanny@ROMAN.NET>
> Subject: Re: The Henson BMHB Stove
> --------------------------------------------------------------------------
-----
>
> http://www.lanny.us/bmhb1.html about 100kb
>
> Stove Friends,
> I am very pleased with my new cook stove. After bringing 2-8QT pots to a

<skip>

From lanny at ROMAN.NET Sat Jan 3 13:00:01 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:47 2004
Subject: The Henson BMHB Stove
Message-ID: <SAT.3.JAN.2004.130001.0500.LANNY@ROMAN.NET>

Ron,
1. Perhaps cooking pinto beans could be used as a cooking efficiency
standard?
2. The two sunken pots can be transferred to the oven to cook while two more
pots are brought to a boil. Once the stove is up to temp it would take less
fuel for the second two pots.
3. The Heart Burner needs to work better first.
Lanny Henson

----- Original Message -----
From: Ron Larson <ronallarson@QWEST.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, January 03, 2004 11:46 AM
Subject: Re: [STOVES] The Henson BMHB Stove

> Lanny:
>
> 1. Congratulations on the results you just sent in. I wonder if we have
a
> record like yours - but you are using a very small amount of wood!
>
> 2. I'm glad I went to your site - I wasn't expecting to see the Bain
Marie
> pots inside an oven! Obviously a very efficient "Hay Box". Was the
picture
> you gave shown with a Rocket Burner?
>
> 3. I don't recall your describing what you mean by a Heart Burner. Could
> you give a citation on "stoves" or your site - or tell us more.
>
> Thansk in advance.
>
> Ron
>
> ----- Original Message -----
> From: Lanny Henson <lanny@ROMAN.NET>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Saturday, January 03, 2004 9:03 AM
> Subject: Re: The Henson BMHB Stove
>
>
> > ---------------------- Information from the mail
> header -----------------------
> > Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
> > Poster: Lanny Henson <lanny@ROMAN.NET>
> > Subject: Re: The Henson BMHB Stove
>
> --------------------------------------------------------------------------
> -----
> >
> > http://www.lanny.us/bmhb1.html about 100kb
> >
> > Stove Friends,
> > I am very pleased with my new cook stove. After bringing 2-8QT pots to a
>
> <skip>
>

From tmiles at TRMILES.COM Sat Jan 3 15:28:04 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:47 2004
Subject: Modeling Efforts
Message-ID: <SAT.3.JAN.2004.122804.0800.TMILES@TRMILES.COM>

Ron

Everything is welcome. We can figure out how to either run or distribute
most things.

Good topic for discussion at the ETHOS meeting. The web presentation of
models would be a good project for the students at U Dayton, or elsewhere,
since students now routinely learn java and visual basic as presentation and
modeling tools. The Java programming language makes it possible to do some
interesting things. (See
http://www.thermofluids.net/ )

Most models are developed in Excel spreadsheets. These can be run (if the
viewer has Excel running on their computer) or converted to something that
can be viewed. I''ve dreamed about putting up web based decision trees
and expert systems for stoves applications. Again, time and money are the
usual limits.

As a practical matter most people make models in which they use a lot of
shortcuts. These models are often useful to the maker but not to others. In
my case they are never quite "finished" because they are used as a
development or design tool. Probably the best way to use these models is to
present an example from the model with verification data from actual stove
tests. The plancha temperature profiles that Mark and his students presented
at the
ETHOS conference last year were a good example of this.

Tom Miles

----- Original Message -----
From: "Ron Larson" <ronallarson@qwest.net>
To: "Crispin Pemberton-Pigott" <crispin@newdawn.sz>;
<STOVES@LISTSERV.REPP.ORG>; <Kanchan@KU.EDU.NP>; "Andreatta, Dale A."
<dandreatta@sealimited.com>; "Tom Miles" <tmiles@trmiles.com>
Sent: Saturday, January 03, 2004 8:30 AM
Subject: Modeling Efforts
> Tom Miles:
>
> 1. Can you tell us the limits on "stoves" ability to handle a
"library"
> of such computer software.
>
>
> Ron
>
>
>
>
> ----- Original Message -----
> From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Saturday, January 03, 2004 6:19 AM
> Subject: RE :AJH: excess air
>
>
> > ---------------------- Information from the mail
> header -----------------------
> > Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
> > Poster: Crispin Pemberton-Pigott <crispin@NEWDAWN.SZ>
> > Subject: RE :AJH: excess air
>
> --------------------------------------------------------------------------
> -----
> >
> > Dear Kanchan
> >
> <snip>
>
>
>

From Gavin at AA3GENERGI.FORCE9.CO.UK Sat Jan 3 15:55:09 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:47 2004
Subject: Comparing paper with wood as fuel.
In-Reply-To: <gvq6uv45lola5t7pejjfeaqt8c8g3te477@4ax.com>
Message-ID: <SAT.3.JAN.2004.205509.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Remember the calcium and other minerals added to modify the performance of
the paper- add to ash content and density.

Paper is heavier than water- try density experiment with a ream- in fact you
can just do the sum as the paper has a g/m2 value-500sheets of A4 gives an
area hence weight and you measure the pack for volume.

ggg
H

From andrew.heggie at DTN.NTL.COM Sat Jan 3 16:31:10 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <27079.202.79.62.12.1073142319.squirrel@www.webmail.ku.edu.np>
Message-ID: <SAT.3.JAN.2004.213110.0000.>

On Sat, 3 Jan 2004 20:50:19 +0545, Kanchan Rai wrote:

>
>I am a regular receiver of emails of stove discussion. This is my first
>time writing on discussion lists.

Hi Kanchan, looks like you are at the front line in the deployment of
this technology, I am an amateur in a society profligate with cheap
energy seeing what I can offer.
>
>There have been lots of discussion regarding EXCESS AIR last week. I like
>to add my view on that though I am not specialist on combustion. I am just
>a begineer.
>
>What is stoichiometric air? Is this sufficient?
>This is the theoritical amount of air required to burn the fuel
>completely. For e.g. 1 kg of pinewood ( C 44.45%, O 33.96 %, H 5.93%, H2O
>15 %, Ash 0.3% w.b.),(Relative humidity 40% ), needs 5.71 kg of air to
>burn completely. Theoritically at this amount of air fuel produced maximum
>of its energy but it practice it is not so.

OK I'll differ from you a bit here, if you can burn something by
supplying just the stoichiometric amount of air, with complete
combustion you will liberate all the energy in the wood, you with also
maximise the temperature. Increase the excess air and, as long as you
do not cause incomplete combustion, and you liberate the same amount
of energy but reduce the temperature. The original point that Tami
made (and I butted in on for some clarification) was that over do the
excess air and you chill the combustion to the point that the reaction
does not go to completion, thus pics are formed.
>
>The sad thing is all air entering the combustion chamber donot
>participates in reaction.

I was asking for clarification on how this air was being defined, I
was looking to see how people were defining excess air, excess air
value, and equivalence ratio. In point of fact none of the combustion
scientists on the list have popped up with definitions.

>This greatly depends upon the stove design and
>fuel loading pattern. Hence we need some more air to complete combustion
>and the air is called EXCESS AIR.

OK but how are you rating that and a ratio of stoich air, as a % of
flue gas. I think combustion engineers use the term equivalence ratio,
which I believe is simply actual air / stoichiometric air. Given this
and an analysis of the flue gas for pics we can relate it to flue gas
oxygen content.

> In small scale biomass combustion
>applications, it is necessary to have excess air ratio well above one,
>usually 1.5, to ensure a sufficient mixing of inlet air and fuel gas.

This mixing is one of the problems with a natural draught stove, a lot
of the secondary flame is reacting by diffusion, the fuel gas is
leaving the fire bed hot and oxygen deficient, it meets air and
combines at the surface "lazily". If we can increase turbulence for
mixing we can reduce the need for excess air because we have increased
the chance of an oxygen molecule meeting a fuel molecule.
>
>DOES EXCESS AIR ALWAYS HELPS COMBUSTION ?
>
>OFCOURSE NOT, if excess air is very much it reduces the combustion
>temperature. BUT HOw!!

As I said excess air will always reduce the combustion temperature as
a whole, but supplied in the correct way I think it need not reduce
the peak flame temperature that the fuel gases pass through. The other
point is poorer fuels (especially wrt moisture content) tend to need
higher excess air to burn out completely. From Gav's posting it is
possible to reduce this, I can see how using fans to increase
turbulence and retention in the combustion chamber can help, not much
use to stoves that must run on natural draught. Often using dry fuel
maximising combustion chamber temperature will cause the materials to
fail, this is especially true of the agri waste fuels which ,
especially the grasses, have ash fusing temperatures much lower than
wood.
>
>Air is composed of 21 % oxygen and 79 % nitrogen (other gases are such as
>Ar, CO2, H2, Xe, Kr etc but comparably neglegible), on which only oxgen
>takes part in combustion. Only less than one third of air is useful for
>combustion. Nitrogen, inspite of helping, absorbing energy from the
>combustion zone, resulting lower combustion temperature and dilution which
>effects on the reaction of oxygen and volatile matters. if 1 kg of
>pinewood is burned with stoichiometric air only 1.2 kg of oxygen takes
>parts in reaction and remaining 4.5 kg of Nitrogen absorbs energy from
>combustion zone.
>
>For 150 % excess air to burn 1 kg of firewood requires 14.3 kg of air, in
>which only 2.98 kg of oxygen takes part in reaction. THINK!!!! what does
>the remaining 11.32 kg Nitrogen contributes for the combustion (only
>negative effect).

OK your excess air is 150% of stoichiometric air, an exav of 2.5?

>The specific heat of Oxygen and nitrogen is 0.795 kJ/kg and 1.04 kJ/kg
>respectively. It is known that to burn out CO, CH4 we need preheated air
>above 600 C.

Other species of pics are created which Tami posted a higher
temperature was necessary to burn out. The requirement is that all the
fuel flux must reach this temperature, this can be by raising the
total flux from cold to this "burn out" temperature (once defined) or
by using a technique like Crispin suggested (which does not increase
total energy released but recycles post combustion heat to increase
the enthalpy of the input air at the cost of a lower flue gas
temperature, which is returned as a result of better combustion,
having no negative impact downstream of where the heat exchange takes
place.

> Assuming air is entering at room temp (no prehaeating) let 20
>C. Nitrogen (11.32 kg) requires 6828 kJ of energy, when air is heated from
>20 C to 600 C) and O2 (2.98 kg) requires 1375 kJ/kg of energy. The heating
>value of pinewood with 15 % moisture is 17.6 MJ/kg. Hence heating air (20
>C - 600C) consumes 46 % of fuel energy, and increase with increase in
>excess air. Hence to much excess is always harmful for clean combustion.

Looks good but somewhere along the line someone needs to figure what
excess air is the optimum for the stove and fuel being used and then
figure a way of ensuring it is correctly supplied without any flue gas
analysis tools.

In point of fact I find using green wood and a fan I need 50% excess
air to give decent CO flue gas figures.

AJH

From andrew.heggie at DTN.NTL.COM Sat Jan 3 16:31:14 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <00ac01c3d1fd$1d2d8780$75cd3c43@MARGARET>
Message-ID: <SAT.3.JAN.2004.213114.0000.>

On Sat, 3 Jan 2004 08:19:13 -0500, Crispin Pemberton-Pigott wrote:

>The trick is to get heat that would normally be lost from the stove and
>chimney into the fire.

Crispin, I can see the benefit of preheating air as an aid to ensuring
complete combustion but if this heat is taken downstream of the pot
then it is heat that has been lost at post pot heat exchange
temperature, which should be in the low 100Cs, otherwise the pot is a
poor heat exchange surface ( OK I know that the pot is a poor heat
exchange surface). What temperatures are being found post pot?
Generally we aim to keep flue gases above 120C to avoid condensate in
the flue.

>Perhaps you can get the 'same heat' to pass by a pot several times. If you
>were wondering whether or not you would get more total heat transferred to a
>pot by passing the hot gasses past it many times or only once, there is a
>paper by physicist Prof Bernhard Scheffler of the University of Pretoria
>which he presented to the Solar '82 conference which many be relevant. He
>showed conclusively that the highest total heat transferred from a solar
>collecter to a hot water tank occurs when the all the water in the tank
>passes through the collector exactly once during the heating cycle

Is this not a special case because the delta T you are looking at on
the primary side is in fact radiant heat from 8 minute old photons and
the other interfaces are straightforward flow of a cold liquid over a
hot surface? If you recirculate the water you are reducing the delta T
between the surfaces. The corollary is in a wet central heating system
where you need to keep the primary water temperature high (say the
return will still be 80 and the output 90 C and recirculated to keep
the radiators functioning well.
AJH

From andrew.heggie at DTN.NTL.COM Sat Jan 3 16:31:17 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:47 2004
Subject: Comparing paper with wood as fuel.
In-Reply-To: <MABBJLGAAFJBOBCKKPMGGEIBDDAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <SAT.3.JAN.2004.213117.0000.>

On Sat, 3 Jan 2004 20:55:09 -0000, Gavin Gulliver-Goodall wrote:

>Remember the calcium and other minerals added to modify the performance of
>the paper- add to ash content and density.

The filler for posh paper is china clay, hydrated aluminium silicate,
from the decomposition of feldspar in granite (guess where I went on
my holiday in St Austell?). I think we had decided newsprint was
likely to be just mechanically pulped paper.
>
>Paper is heavier than water- try density experiment with a ream- in fact you
>can just do the sum as the paper has a g/m2 value-500sheets of A4 gives an
>area hence weight and you measure the pack for volume.

This is the experiment I did with a newspaper here, so either I
measured something wrong or my calculations were out. Anybody out
there got a bulk density for newsprint?

AJH

From andrew.heggie at DTN.NTL.COM Sat Jan 3 16:31:20 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <20040103080726.1496695@telchar.epud.net>
Message-ID: <SAT.3.JAN.2004.213120.0000.>

On Sat, 3 Jan 2004 00:07:24 -0800, Dean Still wrote:

>Dear Kanchan,
>
>Thanks very much for your helpful contribution to the discussion of excess
>air. Determining the amount of air flowing through the stove can be
>difficult to determine. Measuring the flow can disturb it.

Especially difficult as there is no way the user can do this
measurement.
>
>Damon Ogle at Aprovecho has discussed with me that measuring temperature, on
>the other hand, is relatively simple.

The old iron and glass workers were able to make good judgements of
temperature from experience of the materials they were handling.
AJH

From Gavin at AA3GENERGI.FORCE9.CO.UK Sat Jan 3 17:12:15 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <80devv4asian8iqsfh09dkai4ml1r49rpt@4ax.com>
Message-ID: <SAT.3.JAN.2004.221215.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Yep, optical measurement of temperature is pretty straightforward in the
400(C- 100(C range and with experience folk can guess to +-25(C or for
defining a process like glass making/Iron smelting

Airflow measurement will always interfere with flow unless measuring device
is permanently fitted to the burner

Slightly off topic and I know we have discussed this before, is it not
reasonable to make a simple controlled forced draft using bellows/wind up
fan, gravity fan or some such so that heat control and improved air mixing
can be combined? Like toms AA cell powered campstove?
GGG

Especially difficult as there is no way the user can do this
measurement.
>
>Damon Ogle at Aprovecho has discussed with me that measuring temperature,
on
>the other hand, is relatively simple.

The old iron and glass workers were able to make good judgements of
temperature from experience of the materials they were handling.
AJH

From tmiles at TRMILES.COM Sat Jan 3 18:11:12 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:47 2004
Subject: J stove
Message-ID: <SAT.3.JAN.2004.181112.0500.TMILES@TRMILES.COM>

Peter's stove can be found at:
http://www.repp.org/discussiongroups/resources/stoves/PVerhaart/DowndraftBa
rbecue/DDB.htm

I first saw it at a European biomass conference in Orleans, France in the
1980s where Peter discussed "Controlling the heat output rate of
woodburning cookstoves". I'm sure that work lead to some of the
information on http://www.cookstove.net

I can see that I need to add the "J" Stove to the "Stoves A-Z" pages along
with the references to the papers Mike has cited.

Searches on both the stoves website and on the web in general will turn up
many papers on cookstoves but I think it is probably time to start a
database of stoves references, unless someone knows of a particulary good
web database that is accessible to the public. Members of this group know
of many references that are not on the web and may notbe in current
indexes.

Tom Miles

From dstill at EPUD.NET Sat Jan 3 21:35:53 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <MABBJLGAAFJBOBCKKPMGMEIEDDAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <SAT.3.JAN.2004.183553.0800.DSTILL@EPUD.NET>

Gavin asks,

"is it not reasonable to make a simple controlled forced draft using
bellows/wind up fan, gravity fan or some such so that heat control and
improved air mixing can be combined? Like toms AA cell powered campstove?"

Dear Gavin,

We've made a handful of Rocket type sidefeed stoves with fans. Even when the
fan brings in a lot of excess air and temperatures in the combustion chamber
drop down to say 700C, smoke reduction is dramatic. I'm bringing a side feed
Rocket stove with preheated primary air powered by a fan to the
ETHOS/Partnership for Clean Indoor Air meeting, January 31 to Feb 3 in
Seattle.

Textbooks say that Time, Temperature and Turbulence are needed for a clean
burn. Our experiments so far we have only achieved effective Turbulence
(mixing) using a fan. One of the last Stove Seminars concentrated on passive
methods for creating mixing of fuel, air, and spark. But after three days of
trying many different approaches I did not see any substantive successes. We
saw gentle swirl but not a big reduction in smoke.

BUT, quickly blowing air up through the coals or in jets above the fire
reduces smoke more or less completely. A couple of years ago, Ken Goyer
hooked up a variable speed fan to a Rocket stove. As more wood was pushed
into the fire, creating smoke, he increased the airflow which immediately
cleared up the smoke.

I put a Rocket stove on top of a hand powered forge and blew air up through
the coals. No smoke.

I think that we can look to increasing Turbulence (mixing) as the "big gun"
solution to smoke. We know how to get sufficient Time (raise the height of
the combustion chamber). We get high enough temperatures relatively easily.
Jets of air causing mixing gets us very close to "complete combustion", I
think.

After we get all the new emission equipment set up, we can test this idea
and others. I hope that we'll know a lot more about how to successfully burn
wood by 2005. As tests are completed we'll post the data on the REPP and
ETHOS pages beginning this winter.

All Best,

Dean

From Gavin at AA3GENERGI.FORCE9.CO.UK Sun Jan 4 04:12:20 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <20040104023555.3E04BFB@telchar.epud.net>
Message-ID: <SUN.4.JAN.2004.091220.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Dean,
Cool!

So perhaps we need to focus on simple technology to supply the draft in a
convenient and controlled way for cooks to use?

gavin
Gavin asks,

Dear Gavin,

I put a Rocket stove on top of a hand powered forge and blew air up through
the coals. No smoke.

All Best,

Dean

From dstill at EPUD.NET Sun Jan 4 12:05:31 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <MABBJLGAAFJBOBCKKPMGAEIIDDAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <SUN.4.JAN.2004.090531.0800.DSTILL@EPUD.NET>

Dear Gavin,

In my opinion, an easily operated gravity powered fan could help to clean up
smoke. I hope that A.)it lasts for years and B.)costs about one dollar so
that it can be used by the people who might benefit from it. And C.)built
from locally available materials...I'm very much looking forward to testing
whether it's better to 1.)have the air come up through the coals or 2.)mix
the flames from above. Also I guess that we want the fan to 3.)increase
velocity of hot gases contacting the pot but 4.)decrease combustion
temperatures as little as possible. I'd love to see 5.)preheated air coming
into the combustion chamber at really high temperatures although once
temperatures are high then a switch to ceramic from metal is probably
necessary. 6.) Wonder what is the best amount of air to add and 7.)the best
velocity for a stove burning say a kilo of wood per hour?

All Best,

Dean

From Gavin at AA3GENERGI.FORCE9.CO.UK Sun Jan 4 12:33:05 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:47 2004
Subject: AJH: excess air
In-Reply-To: <20040104170532.C281449D@telchar.epud.net>
Message-ID: <SUN.4.JAN.2004.173305.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Dean,
Sounds viable, some sort of brake on the shaft would effect draft control

We were working on 20kg/hr + burners so I doubt my experience is directly
relevant- also, as discussed, much data has been lost

My view is that pre-heated air should be the lowest priority , as my
(slightly empirical ) view is that the complexity does not warrant the extra
(very small heat benefit) VERY hot air might not quench the flame but would
be taking heat away from the combustion chamber area -pre pot and this
heat -stored in a cheap, simple ceramic chamber might be more useful than
transferred across a high temperature alloy heat exchanger. The radiant heat
from the ceramic having essentially the same effect. In larger furnaces a
ceramic arch is often used to help dry wet fuel by re-radiating heat into
the burner area. For wet fuels the primary/secondary air ratio has to be
changed in favour of the primary. With a resultant lowering of efficiency.

Good luck
gavin

From tmiles at TRMILES.COM Sun Jan 4 15:38:59 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:47 2004
Subject: 2004 Wish List
Message-ID: <SUN.4.JAN.2004.123859.0800.TMILES@TRMILES.COM>

Stovers,

It's time to make up a wish list for what you would like to see change on the Stoves list and website for 2004. Bear in mind that there is no budget for anything new but a volunteer group has been working to improve the listserv at REPP and so far REPP has been willing to support increased use of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web. This is in progress by the vounteer group. Archives prior to 2003 are searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone needs to organize the data on refractory and materials of construction, chimneys, etc.

What are your ideas? What would make it easier to find the information you need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

From tombreed at COMCAST.NET Sun Jan 4 09:33:30 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:47 2004
Subject: Chimneys
Message-ID: <SUN.4.JAN.2004.073330.0700.TOMBREED@COMCAST.NET>

Dear Das and All:

I second all of Das's comments, but would like to add a few more on
chimneys.

The chimney is a good solution to combustion, but often

"THE GOOD IS THE ENEMY OF THE BEST".

The need to discard the combustion gases at a high enough temperature to
maintain good draft (say 400 C? - comment?) Means that you are limiting
heat recovery to

(Tc-Td)/Tc

(where Tc is the combustion temperature, Td is the draft temperature)

This is like a Carnot law for Chimneys: It sets the upper bound of
efficiency. If the fuel is burned near stoichimetric, Tc~1600 C, so a draft
temperature of 400 C would limit top efficiency to 75% (neglecting high/low
heating value concerns). However, it is difficult to burn coal or wood at
that temperature, so this is an upper bound for efficiency.

Today it is relatively easy and inexpensive to put an oxygen (lambda) sensor
on a stack and monitor the stoichiometry which then controls combustion
temperature and efficiency.

~~~~~~~
This efficiency loss is a high penalty for using a thermal draft. You can
avoid it for biomass fuels by using a forced draft system and more precisely
controlling the combustin conditions.

When burning coal, it is inadvisable to condense any water in the stck
because it will contain sulfuric acid and eat up your pipes. However the
sulfur concentration in most biomass is such that you can condense the water
and take advantage of the Higher heating value of the biomass. This means
that in the US where we typically rate fuels on their Higher heating value
you can approach 100% of the HHV efficiency, while in Europe where they
usually use the LHV (no condensation) they are now achieving 110% efficiency
in many condensing biomass fuel installations!

~~~~~~~
So we will all continue to use chimneys as as a practical solution to draft,
but keeping in mind that there is much better technology available when the
price is right.

Onward,

TOM REED

----- Original Message -----
From: "Das" <das@EAGLE-ACCESS.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, January 02, 2004 2:29 PM
Subject: Re: [STOVES] Chimneys

> A recent Stovers posting made the most sound argument for flue pipe.
> It gets the smoke and fumes of failure modes out of your living space.
> As you have seen, I have put a flue on everything that I have here.
>
> An aditional goal of improved combustion is to increase the fraction of
the
> operating time with secondary combustion lightoff. Ideally we aim to
> eliminate all release of uncombusted gases. Small grain fuels sugh as
> chips offer much more steady gas quality and combustion quality.
>
> Larger fuel such as Cord wood goes through drastic cycles with fresh fuel
> extinguishing secondary burn, then excessive heat output, then char burn,
> then repeat the cycle.
>
> You are doing good work. It is an hoonor to work with you.
>
> A. Das
> Original Sources/Biomass Energy Foundation
> Box 7137, Boulder, CO 80306
> das@eagle-access.net
>
> ----------
> > From: Dean Still <dstill@EPUD.NET>
> > To: STOVES@LISTSERV.REPP.ORG
> > Subject: Re: [STOVES] Chimneys
> > Date: Tuesday, December 16, 2003 12:37 AM
> >
> > Dear Alex,
> >
> > Our intention at Aprovecho is always to share all information and we
hope
> > that beginning this winter we can generate some accurate numbers for
> various
> > stoves. We received the $8,000 Enerac 3000E today! Should give us good
> > readings of CO, CO2, O2, hydrocarbons...Thanks to the Murdock
> Foundation...
> >
> > I look at chimneys in a very positive light because the cost is low and
> the
> > cure to indoor air pollution, for all practical purposes, complete. Here
> in
> > Oregon, we heat with wood, many folks use wood stoves as their only
> heating
> > source. Chimneys here need to be cleaned often, more often if the stove
> > burns badly as most do, some monthly. It is important to make the
chimney
> > easy to clean. The metal chimney in my house is twenty years old. The 55
> > gallon barrel stove that heats our lab is more than twenty years old.
> > Chimneys are the answer to IAP; the only question is how to fund their
> > installation.
> >
> > The best combustion chamber can be easily defeated by operator error.
> > Although fans and 1,000F preheated primary air are much harder to defeat
> > than stoves relying on natural draft. I love blast furnace heating
stoves
> > coupled to big heat exchangers! But simple cooking stoves without fans
> are
> > usually stuffed full of too much fuel, green as an apple. A chimney
> guards
> > the operator from their actions. Just have to clean it once in a while.
> Buy
> > good stuff...
> >
> > Larry wants us to make light weight chimneys out of ceramic. Ken Goyer
> > extruded a beauty a while back...
> >
> > All Best,
> >
> > Dean

From adkarve at PN2.VSNL.NET.IN Sun Jan 4 19:28:20 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:47 2004
Subject: compact biogas plant
Message-ID: <MON.5.JAN.2004.055820.0530.ADKARVE@PN2.VSNL.NET.IN>

Several members asked me to provide more details about the compact
biogas plant being developed by us. I give below the latest status of
this technology.
The biogas plant consists of two cylindrical vessels telescoping into
one another. The larger vessel, called the fermenter, has a total
internal volume of about 500 lit. A drum having diameter of 85 cm and
height of 85 cm would have the desired volume. The smaller vessel, which
telescopes into the larger one, serves as the gas-holder. The diameter
of the gas holder is about 2 cm smaller than that of the fermenter. The
fermenter vessel is provided with appropriate inlet and outlet pipes for
introducing the feedstock into it and for removal of spent slurry from
it. The gas holder is provided with a gas tap, through which the gas is
led to the burner. This system uses starchy or sugary material as
feedstock. 1kg of sugar or starch yields about 400 litres of methane,
within a period of 6 to 8 hours. This quantity is enough for cooking one
meal for 5 to 6 persons. The biogas produced by this system contains
theoretically about equal volumes of carbondioxide and methane, but in
reality, it turned out to have less than 5% carbondioxide. This
phenomenon is explained by the fact that carbon dioxide dissolves in the
water in the fermenter vessel and diffuses out of it through the 1 cm
gap between the fermenter and the gas holder. The gas produced by this
system has thus almost the same calorific value as LPG. It burns without
smoke or soot, producing an almost invisible bluish flame similar to
that of LPG.

Several prototypes, in operation for more than a year, have been
successfully tested using various feedstocks. The potential candidate
feedstocks, namely rain damaged or insect damaged grain, flour spilled
on the floor of a flour mill, oilcake from non-edible oilseeds, seed of
various tree species, non-edible rhizomes (banana, arums, dioscoreas),
leftover food, spoiled and misshapen fruits, non-edible and wild fruits,
spoilt fruit juice, etc. are readily available in rural areas. This
system is much easier to operate than the dung based biogas plant,
because of the relatively small quantities of feedstock and effluent
slurry to be handled. The effluent slurry generated daily by the plant
is just a couple of litres. It can be used as manure for plants growing
around the house. The 500 litre biogas plant, mass produced from moulded
plastic drums, would cost about Rs. 3,500 (US$ 78). The smallest
cattle-dung based domestic biogas plant costs about Rs. 12,000 (US$267).
It requires daily 40kg dung, and owing to the retention period of almost
40 days, such plants have a minimum capacity of 2000 litres. They
generate daily 80 to 100 litres of effluent slurry. Daily handling of
such large quantities of feedstock and effluent is considered to be
arduous and bothersome by users.
Preliminary studies indicated that the amount of biogas produced and the
retention period varied from feedstock to feedstock and from season to
season. Also, when the feedstock was changed from one form to another,
the system took a few days to stabilise. Our studies also indicated that
the gas yield could be increased by using combinations of feedstock
materials. We are now looking at additives such as micronutrients,
nitrogen, phosphorous compounds etc., which might bacterial action and
yield more gas at a faster rate. Since the users would depend mainly
upon locally available feedstock, field trials are essential to
determine the retention periods and gas yield for different raw materials.
Many people in India, who read my article in a local neuspaper, copied
our design and have started to use this biogas plant in their
households. A schoolgirl submitted a working model of it in a statewide
science project competition and won the first prize in the state. A
company supplying science equipment to educational institute wants to
manufacture models (50 litre capacity) for supply to schools and colleges.
We have supplied 200 litre models to 10 voluntary agencies in different
regions for demonstrating this technology to villagers in their
respective areas. This model is meant for areas where the main diet is
rice. This model yields enough gas to operate a pressure cooker to cook
rice, beans, vegetables or meat for a family of five. In areas, where
the main diet of the people consists of unleavened flat bread, somewhat
like the tortilla, each piece of bread is made individually, and
therefore the stove has to be in operation for a longer time. In such
cases, we recommend the five hundred litre model.

A.D.Karve

From jeff.forssell at CFL.SE Mon Jan 5 05:48:22 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:30:47 2004
Subject: Chimneys = oldest environmental dumping in the common lap
Message-ID: <MON.5.JAN.2004.114822.0100.JEFF.FORSSELL@CFL.SE>

> When burning coal, it is inadvisable to condense any water in the stack
> because it will contain sulfuric acid and eat up your pipes.

So don't let it condense there, send it out to eat up the Earth! :-)

From adkarve at PN2.VSNL.NET.IN Mon Jan 5 09:59:19 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:47 2004
Subject: Green-Manures
Message-ID: <MON.5.JAN.2004.202919.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Ray,

Jackfruit seed is full of starch. The tree is highly productive, with
each tree producing upto 50 large fruits (for those of the readers not
knowing the tropical flora, the fruit of this plant is a composite
fruit, weighing 10 to 20 kg. The seeds are large, about 3 cm long and 2
cm across). So far we selected trees having fruits that gave more of the
sugary flesh and less of seed, but I am quite sure, that out there in
the forest, there are individual trees that have large seeds and less
flesh. In areas having less rainfall, tamarind trees can serve as an
arborescent source of starch. In this case too one can serch for
individual trees that have large seeds and less flesh in the fruit. If
such trees are discovered, one can easily clone them by simple process
of grafting. Jackfruit is also a source of good quality timber, which is
an additional benefit.
As to substituting urea with Gliricidia leaves, the organic farmers in
India believe, that by adding organic matter to the soil, one is not
feeding the plants but feeding the bacteria in the soil. The bacteria in
turn feed the plants. In fact, roots of almost all plant species store
starch, a part of which is converted into polysaccharides called
mucilage. This mucilaginous sheath around the roots harbour millions of
bacteria, that utilise the mucilage as food and do jobs like nitrogen
fixing, solubilisation of phosphorus, killing pathogenic fungi and
insect pests etc. Many farmers in India have nowdays given up using
chemical fertilizers. They provide their crops with 10 kg sugar per acre
instead of chemicals. I met many of them and saw their fields with my
own eyes. The vigour and health of their crops and the yield levels are
just unbelievable.
Yours
A.D.Karve

Ray Wijewardene wrote:

>My dear AD... Our congratulations on yet another brilliant item of simple
>and practical innovation... As Priya and you know, I construct and
>experiment with every item of innovation from your most enlightened
>establishment and pass them on to the farmers around our coconut plantation
>(as visited by Priya, too) to observe their reaction to them. The easy
>availability of waste fuel.. coconut branches etc.,.. is rather a deterent
>to innovation for alternatives!...
>
>However, I am now coming to the realisation that there needs to be TWO clear
>and distinct benefits ... the main-benefit and the 'spin-off' benefit... for
>such innovations to be accepted.
>
>For many years I urged the 'SALT' Sloping-Agricultural-Land-Technology or
>hedgerow-planting of NF trees in contoured avenues between crops (mostly
>arable) which were planted on sloping, rain-fed lands... Also termed
>'alley-cropping' or 'hedge-row-planting' at IITA where I
>served many years
>in the late 70s. But this never seemed REALLY to 'take-off' (the fertility
>aspect could not be 'seen' as well as the urea earlier imported and applied
>by hand.
>
>Now that we have found a way to make use of the fuel-wood of the branches
>for electricity generation and thermal-heat (a very profitable - 60%
>saving -substitute for the furnace oil used in factories for process-heat)
>These factories are happy to pay SL.Rs.2 (about 2 UScents)per kg for the
>fuel-wood which is then gasified) there is ready acceptance of the
>green-manure in place of the urea. The Coconut Research Institute has
>published a figure of '35 kg of the green manure from Gliricidia having the
>N equivalent of 800 gms of urea'... the latter costing some SLRs.13... This
>being the annual requirement of an average coconut palm. ...
>
>BTW. Dr. Karve How do these figures correlate with your own?
>
>In the more undulating 'humid/semi-humid-tropics' as is
> much of Sri Lanka,
>we find that the rain-fed uplands perform much better (more sustainably) for
>agriculture when growing tree-crops rather than the arable-crops which are
>somewhat more popular in India. As you know we are now trying to popularise
>Sustainably-Grown-Fuelwood (SGF) trees as source for domestically generated
>electricity, throughout the country, (as alternative to imported and far
>more costly fossil-fuelled generation). Gliricidia, Accacia, Leucaena,
>Calliandra being the most popular and even where coconut, tea- or rubber
>(our main export crops) might not be grown.
>
>AD... While looking for a 'tree-crop' that might produce the waste starches
>for your biogas plant, one thought has been 'cassava'. While having plenty
>of waste starchy material in the roots, we've not found the wood-branches
>much use as fuel-wood, nor the leaves as fodder/forage. Have you any other
>thoughts to suggest for fuel-wood-producing starch crops. Whi
>le maize has
>been a popular starch-food crop in tropical Africa, the associated problems
>of erosion of the tilled-land has been a major constraint to its sustainable
>production, and was one of the major reasons for the earlier introduction of
>the 'alley-cropping' and 'no-till' systems towards avoiding disturbance of
>the soil.... Rice, grown on levelled land, is far less prone to erosion of
>the soils... However on our undulating and rain-fed uplands, the growing of
>tree-crops (which require no disturbance of the soils round them) have
>proven a really sustainable agriculture. On tea lands the earlier practise
>of scraping the soils free of weeds is heavily discouraged in favour of the
>low-mammalian-toxicity herbicides.
>
>We are now trying to re-popularise the alley-cropping or hedge-row system
>into the more steep hill-country with the added income, now, (apart from the
>added fertility.. which although considerable, is not 'seen' as is 'ur
>ea')
>from sale of fuel-wood produced when the branches are lopped. .. Small
>industries in the country-side are converting from fuel-oil to gasified
>fuel-wood, and also generators.. plant sizes varying from 500 kW to 1
>MW...and also to one of 6 Mw!.. This has promoted a new rural industry which
>is environmentally VERY beneficial. We try to limit these to 1 MW so the
>generator remains a 'small-industry' and SGF transportation is no great
>problem.
>
>Our more popular gasifiers come from India (ANKUR) and the generating sets
>also from the Indian firms, Dipco and Kirloscar whose natural-gas engines
>(spark ignition) are in quantity production following the encouragement
>given by the GOI to manufacture gas (natural-gas) engines in place of diesel
>engines. Even though these engines are derated by about 50% when running off
>wood-gas, they are still more profitable than using diesel engines at the
>now escalating prices for diesel-oil.
>
>A
>t my coconut farm (where we are now 'plagued' with visitors who want to be
>shown the system in operation) all the palms receive an annual dose of 50 kg
>of green-manure (for the 1 kg urea earlier applied) with added potash and
>phosphates and magnesium ... buried in circles round the palm) while the
>fuel-wood loppings go into the gassifier which generates electricity for all
>farm cottages as well as for the water-pumps to supply our 'drip-irrigation'
>system feeding 50 litres of water per day per palm throughout our (approx.
>90-days) of drought-season.... The fact that our coconut farm is becoming
>known for having very high coconut yields has somewhat increased our influx
>of visitors... really a nuisance, now! (AD will know our Asian concerns for
>'evil-eye' and 'evil-mouth', and consequent need for 'ceremonies' to
>'ward-off' such!)... a group of 150 is coming next week much to my farm
>manager's VERY great concern!
>
>In recent months I hav
>e been plagued with the latest 'western' infection of
>SPAM... and had to incorporate a variety of 'spam-guards' which all cost
>money!... Like the virus-guards earlier. I have disconnected myself from all
>programs other than STOVES as my server swears that these are the source for
>my email address being used by spammers.. which reached about 75 a day!!
>
>With warm regards, also, to Mrs. AD and Priya.
>
>RAY WIJEWARDENE
>
>
>
>
>
>
>
>RAY Wijewardene.
>
>
>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of A.D. Karve
>Sent: Monday, January 05, 2004 6:28 AM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: [STOVES] compact biogas plant
>
>
> Several members asked me to provide more details about the compact
>biogas plan
>t being developed by us. I give below the latest status of
>this technology.
>The biogas plant consists of two cylindrical vessels telescoping into
>one another. The larger vessel, called the fermenter, has a total
>internal volume of about 500 lit. A drum having diameter of 85 cm and
>height of 85 cm would have the desired volume. The smaller vessel, which
>telescopes into the larger one, serves as the gas-holder. The diameter
>of the gas holder is about 2 cm smaller than that of the fermenter. The
>fermenter vessel is provided with appropriate inlet and outlet pipes for
>introducing the feedstock into it and for removal of spent slurry from
>it. The gas holder is provided with a gas tap, through which the gas is
>led to the burner. This system uses starchy or sugary material as
>feedstock. 1kg of sugar or starch yields about 400 litres of methane,
>within a period of 6 to 8 hours. This quantity is enough for cooking one
>meal for 5 to 6 persons.
>The biogas produced by this system contains
>theoretically about equal volumes of carbondioxide and methane, but in
>reality, it turned out to have less than 5% carbondioxide. This
>phenomenon is explained by the fact that carbon dioxide dissolves in the
>water in the fermenter vessel and diffuses out of it through the 1 cm
>gap between the fermenter and the gas holder. The gas produced by this
>system has thus almost the same calorific value as LPG. It burns without
>smoke or soot, producing an almost invisible bluish flame similar to
>that of LPG.
>
>Several prototypes, in operation for more than a year, have been
>successfully tested using various feedstocks. The potential candidate
>feedstocks, namely rain damaged or insect damaged grain, flour spilled
>on the floor of a flour mill, oilcake from non-edible oilseeds, seed of
>various tree species, non-edible rhizomes (banana, arums, dioscoreas),
>leftover food, spoiled and misshapen fruits, n
>on-edible and wild fruits,
>spoilt fruit juice, etc. are readily available in rural areas. This
>system is much easier to operate than the dung based biogas plant,
>because of the relatively small quantities of feedstock and effluent
>slurry to be handled. The effluent slurry generated daily by the plant
>is just a couple of litres. It can be used as manure for plants growing
>around the house. The 500 litre biogas plant, mass produced from moulded
>plastic drums, would cost about Rs. 3,500 (US$ 78). The smallest
>cattle-dung based domestic biogas plant costs about Rs. 12,000 (US$267).
>It requires daily 40kg dung, and owing to the retention period of almost
>40 days, such plants have a minimum capacity of 2000 litres. They
>generate daily 80 to 100 litres of effluent slurry. Daily handling of
>such large quantities of feedstock and effluent is considered to be
>arduous and bothersome by users.
>Preliminary studies indicated that the amount of bio
>gas produced and the
>retention period varied from feedstock to feedstock and from season to
>season. Also, when the feedstock was changed from one form to another,
>the system took a few days to stabilise. Our studies also indicated that
>the gas yield could be increased by using combinations of feedstock
>materials. We are now looking at additives such as micronutrients,
>nitrogen, phosphorous compounds etc., which might bacterial action and
>yield more gas at a faster rate. Since the users would depend mainly
>upon locally available feedstock, field trials are essential to
>determine the retention periods and gas yield for different raw materials.
>Many people in India, who read my article in a local neuspaper, copied
>our design and have started to use this biogas plant in their
>households. A schoolgirl submitted a working model of it in a statewide
>science project competition and won the first prize in the state. A
>company supplying scienc
>e equipment to educational institute wants to
>manufacture models (50 litre capacity) for supply to schools and colleges.
>We have supplied 200 litre models to 10 voluntary agencies in different
>regions for demonstrating this technology to villagers in their
>respective areas. This model is meant for areas where the main diet is
>rice. This model yields enough gas to operate a pressure cooker to cook
>rice, beans, vegetables or meat for a family of five. In areas, where
>the main diet of the people consists of unleavened flat bread, somewhat
>like the tortilla, each piece of bread is made individually, and
>therefore the stove has to be in operation for a longer time. In such
>cases, we recommend the five hundred litre model.
>
>A.D.Karve
>
>

From lanny at ROMAN.NET Mon Jan 5 18:17:55 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:47 2004
Subject: compact biogas plant
Message-ID: <MON.5.JAN.2004.181755.0500.LANNY@ROMAN.NET>

Dear Dr Karve,
I am always impressed with your work, the kilns and char briquettes, your
very efficient charcoal stove and now the simple biogas unit that uses sugar
and starch.
I have a few questions about your biogas unit.
1. How often do you have to remove the spent slurry?
2. Does the slurry have a consistency that would flow through a pipe? What
diameter?
3. Can the liquid be reused of does it take a complete flush?
4. Is it a continuous process where you just add some feed stock 2 or 3
times a day or is it a batch process?
5. How cold can the unit be and function well enough to cook twice a day?
6. Could you use yeast to produce gas and alcohol?
7. Is process just natural decomposition? Is there special strains of
bacteria that work better?
Your admirer,
Lanny Henson

----- Original Message -----
From: A.D. Karve <adkarve@PN2.VSNL.NET.IN>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 7:28 PM
Subject: [STOVES] compact biogas plant

> Several members asked me to provide more details about the compact
> biogas plant being developed by us. I give below the latest status of
> this technology.
> The biogas plant consists of two cylindrical vessels telescoping into
> one another. The larger vessel, called the fermenter, has a total
> internal volume of about 500 lit. A drum having diameter of 85 cm and
> height of 85 cm would have the desired volume. The smaller vessel, which
> telescopes into the larger one, serves as the gas-holder. The diameter
> of the gas holder is about 2 cm smaller than that of the fermenter. The
> fermenter vessel is provided with appropriate inlet and outlet pipes for
> introducing the feedstock into it and for removal of spent slurry from
> it. The gas holder is provided with a gas tap, through which the gas is
> led to the burner. This system uses starchy or sugary material as
> feedstock. 1kg of sugar or starch yields about 400 litres of methane,
> within a period of 6 to 8 hours. This quantity is enough for cooking one
> meal for 5 to 6 persons. The biogas produced by this system contains
> theoretically about equal volumes of carbondioxide and methane, but in
> reality, it turned out to have less than 5% carbondioxide. This
> phenomenon is explained by the fact that carbon dioxide dissolves in the
> water in the fermenter vessel and diffuses out of it through the 1 cm
> gap between the fermenter and the gas holder. The gas produced by this
> system has thus almost the same calorific value as LPG. It burns without
> smoke or soot, producing an almost invisible bluish flame similar to
> that of LPG.
>
> Several prototypes, in operation for more than a year, have been
> successfully tested using various feedstocks. The potential candidate
> feedstocks, namely rain damaged or insect damaged grain, flour spilled
> on the floor of a flour mill, oilcake from non-edible oilseeds, seed of
> various tree species, non-edible rhizomes (banana, arums, dioscoreas),
> leftover food, spoiled and misshapen fruits, non-edible and wild fruits,
> spoilt fruit juice, etc. are readily available in rural areas. This
> system is much easier to operate than the dung based biogas plant,
> because of the relatively small quantities of feedstock and effluent
> slurry to be handled. The effluent slurry generated daily by the plant
> is just a couple of litres. It can be used as manure for plants growing
> around the house. The 500 litre biogas plant, mass produced from moulded
> plastic drums, would cost about Rs. 3,500 (US$ 78). The smallest
> cattle-dung based domestic biogas plant costs about Rs. 12,000 (US$267).
> It requires daily 40kg dung, and owing to the retention period of almost
> 40 days, such plants have a minimum capacity of 2000 litres. They
> generate daily 80 to 100 litres of effluent slurry. Daily handling of
> such large quantities of feedstock and effluent is considered to be
> arduous and bothersome by users.
> Preliminary studies indicated that the amount of biogas produced and the
> retention period varied from feedstock to feedstock and from season to
> season. Also, when the feedstock was changed from one form to another,
> the system took a few days to stabilise. Our studies also indicated that
> the gas yield could be increased by using combinations of feedstock
> materials. We are now looking at additives such as micronutrients,
> nitrogen, phosphorous compounds etc., which might bacterial action and
> yield more gas at a faster rate. Since the users would depend mainly
> upon locally available feedstock, field trials are essential to
> determine the retention periods and gas yield for different raw materials.
> Many people in India, who read my article in a local neuspaper, copied
> our design and have started to use this biogas plant in their
> households. A schoolgirl submitted a working model of it in a statewide
> science project competition and won the first prize in the state. A
> company supplying science equipment to educational institute wants to
> manufacture models (50 litre capacity) for supply to schools and colleges.
> We have supplied 200 litre models to 10 voluntary agencies in different
> regions for demonstrating this technology to villagers in their
> respective areas. This model is meant for areas where the main diet is
> rice. This model yields enough gas to operate a pressure cooker to cook
> rice, beans, vegetables or meat for a family of five. In areas, where
> the main diet of the people consists of unleavened flat bread, somewhat
> like the tortilla, each piece of bread is made individually, and
> therefore the stove has to be in operation for a longer time. In such
> cases, we recommend the five hundred litre model.
>
> A.D.Karve
>

From adkarve at PN2.VSNL.NET.IN Mon Jan 5 21:36:52 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:47 2004
Subject: compact biogas plant
Message-ID: <TUE.6.JAN.2004.080652.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Mr. Henson,
The fermenter vessel contains almost 200 litres of liquid. When you
pour a few litres of feedstock slurry into the biogas plant, a
corresponding quantity comes out of the outlet pipe. Because the
material to be fed into the biogas plant consists mainly of starch and
sugary material like sugarcane juice or fruit pulp, the slurry consists
almost exclusively of water with a little suspended matter in it. In the
case of cattle dung or municipal soild waste, the slurry is thicker,
because the feedstock material contains a lot of cellulose and lignin,
which are not as easily digestible as starch or sugar. Because the
effluent also consists of bacteria, and because the quantum of the
effluent is very small (just a few litres), we mix the starch powder or
fruit pulp into the effluent slurry and recycle it. We are currently
advocating that the feedstock be fed into the biogas plant once in the
morning and once again in the evening. Because the reaction time is
short, one can theoretically have a continuous drip feed, but the
relatively high viscosity of the feedstock may cause mechanical problems
like clogging of the dripper. It may also be theoretically possible to
produce alcohol and methane simultaneously, but we haven't looked for
alcohol. The system however runs on vinegar, which is the oxidised
product of alcohol. The system is sensitive to temperature. Here in Pune
it is not as cold as in the US, but at present the night temperatures
touch 10 degrees C. This lowering of the night temperature has reduced
the gas outflow considerably. However, it would not be difficult to
cover the drums with an insulating material and conserve the heat
produced by the bacterial process. I t would however add to the cost of
the system. We do not use any special bacteria. To begin with we mix
about 10 kg cattle dung and water and pour the slurry into the
fermenter. However, to make the system more readily acceptable to the
users, we shall have to produce the culture ourselves and give it to the
users along with the biogas plant. Dung is a dirty and smelly material.
In the initial phase, we add daily just 200 grams of flour. When gas
starts emanating, we test it for its combustibility. We get combustible
gas in 7 to 15 days.After the methane production has started, we
increase the daily dose of 1 kg starch at each feeding. The inlet and
outlet pipes have a diameter of about 5 cm.
A.D.Karve

Lanny Henson wrote:

>Dear Dr Karve,
>I am always impressed with your work, the kilns and char briquettes, your
>very efficient charcoal stove and now the simple biogas unit that uses sugar
>and starch.
>I have a few questions about your biogas unit.
>1. How often do you have to remove the spent slurry?
>2. Does the slurry have a consistency that would flow through a pipe? What
>diameter?
>3. Can the liquid be reused of does it take a complete flush?
>4. Is it a continuous process where you just add some feed stock 2 or 3
>times a day or is it a batch process?
>5. How cold can the unit be and function well enough to cook twice a day?
>6. Could you use yeast to produce gas and alcohol?
>7. Is process just natural decomposition? Is there special strains of
>bacteria that work better?
>Your admirer,
>Lanny Henson
>
>----- Original Message -----
>From: A.D. Karve <adkarve@PN2
>.VSNL.NET.IN>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Sunday, January 04, 2004 7:28 PM
>Subject: [STOVES] compact biogas plant
>
>
>> Several members asked me to provide more details about the compact
>>biogas plant being developed by us. I give below the latest status of
>>this technology.
>>The biogas plant consists of two cylindrical vessels telescoping into
>>one another. The larger vessel, called the fermenter, has a total
>>internal volume of about 500 lit. A drum having diameter of 85 cm and
>>height of 85 cm would have the desired volume. The smaller vessel, which
>>telescopes into the larger one, serves as the gas-holder. The diameter
>>of the gas holder is about 2 cm smaller than that of the fermenter. The
>>fermenter vessel is provided with appropriate inlet and outlet pipes for
>>introducing the feedstock into it and for removal of spent slurry from
>>it. The gas holder is provided with a gas tap, through which the gas is
>>led to the burner. This system uses starchy or sugary material as
>>feedstock. 1kg of sugar or starch yields about 400 litres of methane,
>>
>>within a period of 6 to 8 hours. This quantity is enough for cooking one
>>meal for 5 to 6 persons. The biogas produced by this system contains
>>theoretically about equal volumes of carbondioxide and methane, but in
>>reality, it turned out to have less than 5% carbondioxide. This
>>phenomenon is explained by the fact that carbon dioxide dissolves in the
>>water in the fermenter vessel and diffuses out of it through the 1 cm
>>gap between the fermenter and the gas holder. The gas produced by this
>>system has thus almost the same calorific value as LPG. It burns without
>>smoke or soot, producing an almost invisible bluish flame similar to
>>that of LPG.
>>
>>Several prototypes, in operation for more than a year, have been
>>successfully tested using various feedstocks. The potential candidate
>>feedstocks, namely rain damaged or insect damaged grain, flour spilled
>>on the floor of a flour mill, oilcake from non-edible oilseeds, seed of
>>various tree specie
>>s, non-edible rhizomes (banana, arums, dioscoreas),
>>leftover food, spoiled and misshapen fruits, non-edible and wild fruits,
>>spoilt fruit juice, etc. are readily available in rural areas. This
>>system is much easier to operate than the dung based biogas plant,
>>because of the relatively small quantities of feedstock and effluent
>>slurry to be handled. The effluent slurry generated daily by the plant
>>is just a couple of litres. It can be used as manure for plants growing
>>around the house. The 500 litre biogas plant, mass produced from moulded
>>plastic drums, would cost about Rs. 3,500 (US$ 78). The smallest
>>cattle-dung based domestic biogas plant costs about Rs. 12,000 (US$267).
>>It requires daily 40kg dung, and owing to the retention period of almost
>>40 days, such plants have a minimum capacity of 2000 litres. They
>>generate daily 80 to 100 litres of effluent slurry. Daily handling of
>>such large quantities of feedstock and effluent is conside
>>red to be
>>arduous and bothersome by users.
>>Preliminary studies indicated that the amount of biogas produced and the
>>retention period varied from feedstock to feedstock and from season to
>>season. Also, when the feedstock was changed from one form to another,
>>the system took a few days to stabilise. Our studies also indicated that
>>the gas yield could be increased by using combinations of feedstock
>>materials. We are now looking at additives such as micronutrients,
>>nitrogen, phosphorous compounds etc., which might bacterial action and
>>yield more gas at a faster rate. Since the users would depend mainly
>>upon locally available feedstock, field trials are essential to
>>determine the retention periods and gas yield for different raw materials.
>>Many people in India, who read my article in a local neuspaper, copied
>>our design and have started to use this biogas plant in their
>>households. A schoolgirl submitted a working model of it in a statewi
>>de
>>science project competition and won the first prize in the state. A
>>company supplying science equipment to educational institute wants to
>>manufacture models (50 litre capacity) for supply to schools and colleges.
>>We have supplied 200 litre models to 10 voluntary agencies in different
>>regions for demonstrating this technology to villagers in their
>>respective areas. This model is meant for areas where the main diet is
>>rice. This model yields enough gas to operate a pressure cooker to cook
>>rice, beans, vegetables or meat for a family of five. In areas, where
>>the main diet of the people consists of unleavened flat bread, somewhat
>>like the tortilla, each piece of bread is made individually, and
>>therefore the stove has to be in operation for a longer time. In such
>>cases, we recommend the five hundred litre model.
>>
>>A.D.Karve
>>
>

From Kanchan at KU.EDU.NP Tue Jan 6 15:11:36 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:30:47 2004
Subject: Excess air
Message-ID: <WED.7.JAN.2004.015636.0545.KANCHAN@KU.EDU.NP>

Thank everyone for good response of my first email in stove discussion list.

Dean:
Thank you for your suggestions
YES it is true that it is difficult to measure air flowing through the
stove especially when the combustion chamber has no door (e.g. rocket
stove). In my view there is 2 methods of determining the amount of air
flowing through the stove

1. Measuring air velocity at the inlet

For this an Anemometer can be used. The cross section area from which area
is entering should be known. Knowing air velocity we can calculate air
flow rate. Since there is always change in air entering velocity, the
annemometer reading shows the fluctuation. I have tried this method during
my stove (a metal stove with a door) test. In my observation, the velocity
of air is less at start, but at steady state combustion, air velocity is
nearly constant and goes down at the end.

2. Measuring flue gas velocity at the exhaust (chimney)
This method requires a reliable instrument as we are dealing with high
temperature gases. For this we can use either a Pitot Tube or a Hot wire
anemometer.Measuring the gas velocity and fuel burn rate we can calculate
the amount of air used in combustion. For a known burn rate we can
calculate the stoichiometric amount of air, comparing that with the
measured value we can calculate the excess air. But complication comes
with the variable air velocity during the test in the chimney. For that we
have to measure the flue velocity through out the test and using some
mathematics we can come close to the actual value. But unfortunately I
haven't done this method, as I have very limited resources and equipements
especially dealing high temperatures.

Crispin:

Thank you for your suggestions. Yes I have been working on my spread sheet
on preheated secondary air.
But I think for preheating if the energy is used from the combustion
chamber it will lose the combustion energy from the primary combustion
area. But its OK, if we can achieve the air temperature required for
secondary combustion. I guess for the complete combustion it is not good
to take energy from fuel combustion zone. THEN WHY NOT use the energy
after the complete combustion of volatiles. I would like to develop a
secondary combustion zone using the energy from the flue gas after
complete combustion, to preheat the secondary air. In simple using the
secondary combustion energy to heat the secondary air.

I think knowledge is to be share, but at the time i am working on some
parts. As soon as I finish it i'll send it to you. I am also willing to
see your spread sheet too.

Ron:

Like Crispin as soon as I finish some parts of my spread sheet, I'll send
it to you too.

Andrew,
Thanks for your email. I am also agreed with your view that the excess air
doesnot affects the energy liberation as long as the FUEL IS COMPLETELY
COMBUSTED but the thing is when you get excess air you cannot acieve
desire temperature for complete combustion.

I appololise for defining excess air in different (sometime 1.5 and 150%),
I agree its best way to define it in equivalent ratio (excess air 150% is
equiv ratio 2.5). Yes we need to define the optimum excess air for the
stove for its best performance.

kanchan

From Gavin at AA3GENERGI.FORCE9.CO.UK Tue Jan 6 05:56:34 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:48 2004
Subject: Excess air
In-Reply-To: <36018.203.91.135.149.1073419896.squirrel@www.webmail.ku.edu.np>
Message-ID: <TUE.6.JAN.2004.105634.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Anemometer and pitot,/ hot wire techniques require very careful procedure to
be followed to get a reading with any level of reliability.
Temperature and gas composition have an effect as well as flow distribution
across the pipe . for anemometers you have the added complication of flow
obstruction.

You can use them for an indication but for combustion analysis calculations
you will need to do highly accurate , repeatable tests with the stove in a
steady state condition - as the tests will take at least 1/2 an hour to
complete.

Good luck
Gaivn

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On Behalf
Of Kanchan Rai
Sent: Tuesday, January 06, 2004 20:12
To: STOVES@LISTSERV.REPP.ORG
Subject: [STOVES] Excess air

Thank everyone for good response of my first email in stove discussion list.

1. Measuring air velocity at the inlet

Crispin:

I think knowledge is to be share, but at the time i am working on some
parts. As soon as I finish it i'll send it to you. I am also willing to
see your spread sheet too.

Ron:

Like Crispin as soon as I finish some parts of my spread sheet, I'll send
it to you too.

kanchan

From adkarve at PN2.VSNL.NET.IN Tue Jan 6 09:49:41 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: Pressure cookers
Message-ID: <TUE.6.JAN.2004.201941.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Peter,
Pressure cookers were introduced into India about 45 years ago and they
have been accepted by everybody. They are not used in conjunction with
a wood fire, because the flames of a wood fire can sometimes rise very
high, which may burn the plastic handle or damage the rubber gasket. But
practically all households using charcoal, kerosene or gas as fuel, use
a pressure cooker. The only bad part of a pressure cooker is that it
cooks under high temperature. The compounds that impart taste and
flavour to the food are volatile and they are volatilised to a greater
extent at the higher temperature of a pressure cooker. Our Sarai
cooker, which is a non-pressurised cooker, has become very popular in a
very short time, because the food cooked in it tastes much better.
Incidentally, we too use a Hawkins pressure cooker in our own household!
A.D.Karve

Peter Verhaart wrote:

> Dear Dr Karve,
>
> In a reply to Lany Henson (I think), you mention the use of
> pressure cookers.
> Personally I love pressure cookers, ideal for rice, 5 minutes under
> pressure, perfectly cooked rice.
> But! Around us here in Australia I discern great fear of pressure
> cookers, which begs the question: "How is that in India?"
> Also, most pressure cookers here are very expensive with one
> exception, Hawkins, made in India, simple and very good.
>
> Looking forward to meeting you and your daughter face to face in Seattle.
>
> Regards,
>
> Peter Verhaart
>
>

From solar1 at ZUPER.NET Tue Jan 6 11:13:46 2004
From: solar1 at ZUPER.NET (Sobre la Roca: Energ=?ISO-8859-1?B?7Q==?=a Solar para el
Desarrollo)
Date: Tue Aug 10 18:30:48 2004
Subject: Pressure cookers
In-Reply-To: <3FFACB05.6060402@pn2.vsnl.net.in>
Message-ID: <TUE.6.JAN.2004.121346.0400.SOLAR1@ZUPER.NET>

in a previous message, A.D. Karve on 1/6/04 10:49 at adkarve@PN2.VSNL.NET.IN
wrote:

>
> . Our Sarai
> cooker, which is a non-pressurised cooker, has become very popular in a
> very short time, because the food cooked in it tastes much better.
> Incidentally, we too use a Hawkins pressure cooker in our own household!
> A.D.Karve
Dear Dr. Karve
Your posts are always thought provoking. Thanks.
Could you provide details on what is your Sarai cooker, benefits, defects,
and how it is made?
I am looking at improved cooking vessels to be used in efficient wood,
retained heat and solar cookers.
Many thanks
--
David Whitfield
Director
CEDESOL
P.O. Box 4723
La Paz Bolivia South America
591-2-2414882 office 591 715 16356 cellular

solar1@zuper.net
aguaviva@zuper.net
dewv@yahoo.com
http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm

http://www.thehungersite.com

From andrew.heggie at DTN.NTL.COM Tue Jan 6 17:22:59 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:48 2004
Subject: Excess air
In-Reply-To: <36018.203.91.135.149.1073419896.squirrel@www.webmail.ku.edu.np>
Message-ID: <TUE.6.JAN.2004.222259.0000.>

On Wed, 7 Jan 2004 01:56:36 +0545, Kanchan Rai wrote:

>
>Thank you for your suggestions. Yes I have been working on my spread sheet
>on preheated secondary air.

I think I would advocate restricting heating to the secondary air,

>But I think for preheating if the energy is used from the combustion
>chamber it will lose the combustion energy from the primary combustion
>area.

One of the reasons I would be wary of preheating the primary air is
because the grate can easily be burned, often it is the cool primary
air that protects this region. Until someone pipes in with reasons I
assumed the heat exchange for heating the secondary air should come
post combustion, now I can see reasons for this being derived both
from before and after the pot. What I cannot see is how to do this
without some form of forced draught. Tom Reed has pointed out the
potential cost of achieving the draught and this is essentially a
"suck" through the fire, preheating the air not only requires it to be
sucked over a heat exchange surface and then down into the fire
(unless the heat exchange is a massive conductor, but also the power
necessary to suck a hot gas is more than the power required to blow a
cold one (the chimney is providing the power).

>But its OK, if we can achieve the air temperature required for
>secondary combustion. I guess for the complete combustion it is not good
>to take energy from fuel combustion zone. THEN WHY NOT use the energy
>after the complete combustion of volatiles. I would like to develop a
>secondary combustion zone using the energy from the flue gas after
>complete combustion, to preheat the secondary air. In simple using the
>secondary combustion energy to heat the secondary air.

I agree, but how do you propose to do it without a fan or chimney?

>Andrew,
>Thanks for your email. I am also agreed with your view that the excess air
>doesnot affects the energy liberation as long as the FUEL IS COMPLETELY
>COMBUSTED but the thing is when you get excess air you cannot acieve
>desire temperature for complete combustion.

Yes we need a few rules to decide what we can trade off between clean
combustion and heat exchange efficiency.
>
>I appololise for defining excess air in different (sometime 1.5 and 150%),
>I agree its best way to define it in equivalent ratio (excess air 150% is
>equiv ratio 2.5). Yes we need to define the optimum excess air for the
>stove for its best performance.

Certainly no need to apologise, indeed I don't believe you were at all
wrong, I just wanted a bit of clarification for my own thoughts.

AJH

From andrew.heggie at DTN.NTL.COM Tue Jan 6 17:23:02 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:48 2004
Subject: Chimneys
In-Reply-To: <000401c3d307$b4f17260$3b7d0818@cwcn7uspc42i87>
Message-ID: <TUE.6.JAN.2004.222302.0000.>

On Sun, 4 Jan 2004 07:33:30 -0700, TBReed wrote:

>
>The need to discard the combustion gases at a high enough temperature to
>maintain good draft (say 400 C? - comment?) Means that you are limiting
>heat recovery to
>
>(Tc-Td)/Tc

If the heat being rejected after the pot is seriously 400C then we
need to do something about it. I was assuming it was ~200C at worst.
Still shouldn't you equation be related to absolute temperature for
this equation to hold true?

In fact I suspect in the absence of an insulated combustion chamber
and lining up to the pot most metal stoves would be limited to 800C or
high losses away from the walls to protect them.

AJH

From andrew.heggie at DTN.NTL.COM Tue Jan 6 17:23:03 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:48 2004
Subject: AJH: excess air
In-Reply-To: <MABBJLGAAFJBOBCKKPMGKEIJDDAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <TUE.6.JAN.2004.222303.0000.>

On Sun, 4 Jan 2004 17:33:05 -0000, Gavin Gulliver-Goodall wrote:

>Dean,
>Sounds viable, some sort of brake on the shaft would effect draft control

When we talked about this before I suggested a simple fan could be
almost self regulating. Clockwork or falling weight are the only ones
that meet Dean's fabrication criteria, or a refined steam aspirator
;-).

>heat -stored in a cheap, simple ceramic chamber might be more useful than
>transferred across a high temperature alloy heat exchanger. The radiant heat
>from the ceramic having essentially the same effect. In larger furnaces a
>ceramic arch is often used to help dry wet fuel by re-radiating heat into
>the burner area.

I still like the idea of a hot high emissivity refractory radiating
heat to the pot, over the top for this application but consider a
coating of catalyst on this able to drop the spontaneous ignition
temperature of the offgas, a technique similar to this is being
discussed to enable the use of propane in compression ignition engines
( where currently the compression is unable to reach the 600C
required).

> For wet fuels the primary/secondary air ratio has to be
>changed in favour of the primary. With a resultant lowering of efficiency.

Essentially because a lot of the heat liberated from the C => CO2
reaction in the firebed is used up in drying the fuel.

AJH

From snkm at BTL.NET Tue Jan 6 17:21:58 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:48 2004
Subject: compact biogas plant
Message-ID: <TUE.6.JAN.2004.162158.0600.SNKM@BTL.NET>

At 05:58 AM 1/5/2004 +0530, A.D. Karve wrote:
> Several members asked me to provide more details about the compact
>biogas plant being developed by us. I give below the latest status of
>this technology.

Dear A.D.Karve;

I live in Belize, Central America, in a small village "Xaibe" -- that is
literally surrounded in cane fields.

I wonder if an optimized version of your design could be made to operate on
only fresh cane juice??

Have you tried this as of yet??

For the other stovers on the list -- sugar cane is a wonderfully productive
plant for any place in the tropics. Very easy to grow. For a large
percentage of the world's poorest populations it is feasible to have a
small plot of cane. This certainly would solve the "where do we find all
the biomass to burn" problem!

Certainly -- it would be of interest to me to pursue this topic further.

Mr. A.D.Karve -- it is commercially impossible to ship such devices around
the globe. But have you considered diversifying your operation to other
areas??

"Franchising" this gas producer -- based specifically on cane juice --
would be interesting and profitable.

One small cane crusher in each village would suffice for everyone's gas
generator.

Though this is about gas -- and is about small stoves -- there may be a few
on this list adverse to such a discussion being as it deals not with --
what to date -- is considered as standard "stove".

But then -- locking oneself into a rigid mind set is often counter
productive to innovation or eventual application.

By coincidence I happen to have that "one small cane crusher" --

Peter Singfield
Belize

>The biogas plant consists of two cylindrical vessels telescoping into
>one another. The larger vessel, called the fermenter, has a total
>internal volume of about 500 lit. A drum having diameter of 85 cm and
>height of 85 cm would have the desired volume. The smaller vessel, which
>telescopes into the larger one, serves as the gas-holder. The diameter
>of the gas holder is about 2 cm smaller than that of the fermenter. The
>fermenter vessel is provided with appropriate inlet and outlet pipes for
>introducing the feedstock into it and for removal of spent slurry from
>it. The gas holder is provided with a gas tap, through which the gas is
>led to the burner. This system uses starchy or sugary material as
>feedstock. 1kg of sugar or starch yields about 400 litres of methane,
>within a period of 6 to 8 hours. This quantity is enough for cooking one
>meal for 5 to 6 persons. The biogas produced by this system contains
>theoretically about equal volumes of carbondioxide and methane, but in
>reality, it turned out to have less than 5% carbondioxide. This
>phenomenon is explained by the fact that carbon dioxide dissolves in the
>water in the fermenter vessel and diffuses out of it through the 1 cm
>gap between the fermenter and the gas holder. The gas produced by this
>system has thus almost the same calorific value as LPG. It burns without
>smoke or soot, producing an almost invisible bluish flame similar to
>that of LPG.
>
>Several prototypes, in operation for more than a year, have been
>successfully tested using various feedstocks. The potential candidate
>feedstocks, namely rain damaged or insect damaged grain, flour spilled
>on the floor of a flour mill, oilcake from non-edible oilseeds, seed of
>various tree species, non-edible rhizomes (banana, arums, dioscoreas),
>leftover food, spoiled and misshapen fruits, non-edible and wild fruits,
>spoilt fruit juice, etc. are readily available in rural areas. This
>system is much easier to operate than the dung based biogas plant,
>because of the relatively small quantities of feedstock and effluent
>slurry to be handled. The effluent slurry generated daily by the plant
>is just a couple of litres. It can be used as manure for plants growing
>around the house. The 500 litre biogas plant, mass produced from moulded
>plastic drums, would cost about Rs. 3,500 (US$ 78). The smallest
>cattle-dung based domestic biogas plant costs about Rs. 12,000 (US$267).
>It requires daily 40kg dung, and owing to the retention period of almost
>40 days, such plants have a minimum capacity of 2000 litres. They
>generate daily 80 to 100 litres of effluent slurry. Daily handling of
>such large quantities of feedstock and effluent is considered to be
>arduous and bothersome by users.
>Preliminary studies indicated that the amount of biogas produced and the
>retention period varied from feedstock to feedstock and from season to
>season. Also, when the feedstock was changed from one form to another,
>the system took a few days to stabilise. Our studies also indicated that
>the gas yield could be increased by using combinations of feedstock
>materials. We are now looking at additives such as micronutrients,
>nitrogen, phosphorous compounds etc., which might bacterial action and
>yield more gas at a faster rate. Since the users would depend mainly
>upon locally available feedstock, field trials are essential to
>determine the retention periods and gas yield for different raw materials.
>Many people in India, who read my article in a local neuspaper, copied
>our design and have started to use this biogas plant in their
>households. A schoolgirl submitted a working model of it in a statewide
>science project competition and won the first prize in the state. A
>company supplying science equipment to educational institute wants to
>manufacture models (50 litre capacity) for supply to schools and colleges.
>We have supplied 200 litre models to 10 voluntary agencies in different
>regions for demonstrating this technology to villagers in their
>respective areas. This model is meant for areas where the main diet is
>rice. This model yields enough gas to operate a pressure cooker to cook
>rice, beans, vegetables or meat for a family of five. In areas, where
>the main diet of the people consists of unleavened flat bread, somewhat
>like the tortilla, each piece of bread is made individually, and
>therefore the stove has to be in operation for a longer time. In such
>cases, we recommend the five hundred litre model.
>
>A.D.Karve
>

From snkm at BTL.NET Tue Jan 6 17:22:04 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:48 2004
Subject: Green-Manures
Message-ID: <TUE.6.JAN.2004.162204.0600.SNKM@BTL.NET>

Dear A.D.Karve;

>They provide their crops with 10 kg sugar per acre
>instead of chemicals. I met many of them and saw their fields with my
>own eyes. The vigour and health of their crops and the yield levels are
>just unbelievable.
>Yours
>A.D.Karve

I suspect this is applied as a solution of sugar in water??

Saying that 30% of cane juice is sugar -- then 33 kg of cane juice is
sufficient to "fertilize" one acre.

Say -- one acre of sugar cane??

We suffer a terrible foreign exchange burden here to fertilize out cane
fields at present. One thta might not be sustainable.

Peter Singfield / Belize

From Gavin at AA3GENERGI.FORCE9.CO.UK Tue Jan 6 17:52:23 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:48 2004
Subject: Excess air
In-Reply-To: <vi8mvv4h4g8ht8u9kbfn0if141g8prj3bu@4ax.com>
Message-ID: <TUE.6.JAN.2004.225223.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Flue gas recirculation-also hot but not pre heated primary air will cool the
grate buy increasing gas mass flow rate = mixing while reducing oxygen input
= high temperature probably not practical on a stove without an ID fan but I
just thought Id mention it
Gavin

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On Behalf
Of Andrew Heggie
Sent: Tuesday, January 06, 2004 22:23
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Excess air

On Wed, 7 Jan 2004 01:56:36 +0545, Kanchan Rai wrote:

>
>Thank you for your suggestions. Yes I have been working on my spread sheet
>on preheated secondary air.

I think I would advocate restricting heating to the secondary air,

>But I think for preheating if the energy is used from the combustion
>chamber it will lose the combustion energy from the primary combustion
>area.

I agree, but how do you propose to do it without a fan or chimney?

Certainly no need to apologise, indeed I don't believe you were at all
wrong, I just wanted a bit of clarification for my own thoughts.

AJH

From das at EAGLE-ACCESS.NET Wed Jan 7 03:14:44 2004
From: das at EAGLE-ACCESS.NET (Das)
Date: Tue Aug 10 18:30:48 2004
Subject: Excess air simple measurements
Message-ID: <WED.7.JAN.2004.011444.0700.DAS@EAGLEACCESS.NET>

The simplest method of adjusting air fuel ratio with an enclosed secondary
combustion chamber is to observe the flame length. A tiny hole 1/8" for
observation can be plugged with a screw afterwards. This hole/ holes should
allow observation of the secondary burn area from the fuel to the flue
exit.
For this discussion:
Primary Air is the air which hits the char and produces heat which will
increase the rate of production of fuel gases and vapors from the solid
fuel.
Secondary air is the air available to burn the gases and vapors from the
solid fuel.
In an open campfire excess air is the combustion condition outside of the
visible flame.
If secondary combustion has not lit off, then you just have a typical smoky
smouldering stove/flame no matter what the air fuel ratio.

Once secondary combustion has lit off, secondary air can be adjusted.
Changes in secondary air affects the location and amount of heat release.

Starting too rich (no excess air)
Way too little secondary air, and the visible flame will be long and lazy
and enter the flue. The flue may actually glow since it is the point of
greatest heat release. This should be avoided. Un combusted fuel energy
goes up the stack. Visible smoke and CO (pollution) are being released.
Fuel is being wasted. The valley fills with haze. Lives are being
endangered.

Watch the flame shorten as secondary air supply is increased. When the
flame shortens to where it just barely does not enter the flue, then I
would consider this zero excess air. All the combustion is contained
inside the stove. The flue exit should look clearer, less smoke but
occasional puffs may be seen. The sound of the fire will be more vigorous
than with the too little secondary air. The stove may pulsate and puff
smoke out the stove. The flue pipe may still glow because the heat release
is beyond the pan.

Increase secondary air slightly more to shorten the flame and bring it back
to the pan. This is where we want the heat release for cooking. Heat
transfer is both radiant and convective. The flue should be smoke free and
it should not be glowing. The sound may be distinctive. Fuel economy is
best in this condition.

If secondary air is further increased, then the flame will retreat closer
to the fuel. The main heat release will be closer to the fuel away from
the pan. Heat may be lost on the way to the pan.
Tight pan/stove clearance is necessary to increase combustion gas velocity
to get heat into pan. Narrow passages may be more sensitive to creosote
deposits. Fuel economy will be better than open fire if heat losses are
not too high.

All of the above observations should be done without changing the primary
air.
The primary air supply controls the fuel burn rate and the rate of heat
release.
It is a nice convenience feature and important to acceptance that secondary
air should inherently follow changes in burn rate (primary air) or be
easily adjusted and understood.

For stove development purposes the excess air can be monitored using the
tailpipe sensor for gasoline vehicles since 1986 (Exhaust Gas Oxygen, EGO
sensor, Lambda Sensor etc one wire, four wire etc). They are available at
auto parts. These sensors typically give around 0.5 v at stochiometric 1%
O2 in the tailpipe at flue temperatures. It is nice and non linear, so I
will only specify this one point. Tom can fill you in.

Historically the Orstat apparatus has been used for combustion flue gas
analysis using absorbing solutions for CO2, O2, CO, H2, CH4.

A simpler combustion analyzer Bachrach measures only CO2 content using a
lye solution absorbent.
A handy person could probably rig up a method for doing this extremely in
the field using potash liquor extracted from wood ashes. Glassware made
from bottles worked in a blowpipe. Tubing from entrails. It would take a
special person to step up to this challenge. Send me a picture if you do.

I believe the simplest, most rapid and most accessible method of flue
analysis at present is the exhaust gas sensor above.

But when it all comes down to it I trust my eye and ear the most.

A. Das
Original Sources/Biomass Energy Foundation
Box 7137, Boulder, CO 80306
das@eagle-access.net

----------
> From: Gavin Gulliver-Goodall <Gavin@AA3GENERGI.FORCE9.CO.UK>
> To: STOVES@LISTSERV.REPP.ORG
> Subject: Re: [STOVES] Excess air
> Date: Tuesday, January 06, 2004 3:56 AM
>
> Anemometer and pitot,/ hot wire techniques require very careful procedure
to
> be followed to get a reading with any level of reliability.
> Temperature and gas composition have an effect as well as flow
distribution
> across the pipe . for anemometers you have the added complication of flow
> obstruction.
>
> You can use them for an indication but for combustion analysis
calculations
> you will need to do highly accurate , repeatable tests with the stove in
a
> steady state condition - as the tests will take at least 1/2 an hour to
> complete.
>
> Good luck
> Gaivn
>
> -----Original Message-----
> From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf
> Of Kanchan Rai
> Sent: Tuesday, January 06, 2004 20:12
> To: STOVES@LISTSERV.REPP.ORG
> Subject: [STOVES] Excess air
>
> Thank everyone for good response of my first email in stove discussion
list.
>
> Dean:
> Thank you for your suggestions
> YES it is true that it is difficult to measure air flowing through the
> stove especially when the combustion chamber has no door (e.g. rocket
> stove). In my view there is 2 methods of determining the amount of air
> flowing through the stove
>
> 1. Measuring air velocity at the inlet
>
> For this an Anemometer can be used. The cross section area from which
area
> is entering should be known. Knowing air velocity we can calculate air
> flow rate. Since there is always change in air entering velocity, the
> annemometer reading shows the fluctuation. I have tried this method
during
> my stove (a metal stove with a door) test. In my observation, the
velocity
> of air is less at start, but at steady state combustion, air velocity is
> nearly constant and goes down at the end.
>
>
> 2. Measuring flue gas velocity at the exhaust (chimney)
> This method requires a reliable instrument as we are dealing with high
> temperature gases. For this we can use either a Pitot Tube or a Hot wire
> anemometer.Measuring the gas velocity and fuel burn rate we can calculate
> the amount of air used in combustion. For a known burn rate we can
> calculate the stoichiometric amount of air, comparing that with the
> measured value we can calculate the excess air. But complication comes
> with the variable air velocity during the test in the chimney. For that
we
> have to measure the flue velocity through out the test and using some
> mathematics we can come close to the actual value. But unfortunately I
> haven't done this method, as I have very limited resources and
equipements
> especially dealing high temperatures.
>
>
> Crispin:
>
> Thank you for your suggestions. Yes I have been working on my spread
sheet
> on preheated secondary air.
> But I think for preheating if the energy is used from the combustion
> chamber it will lose the combustion energy from the primary combustion
> area. But its OK, if we can achieve the air temperature required for
> secondary combustion. I guess for the complete combustion it is not good
> to take energy from fuel combustion zone. THEN WHY NOT use the energy
> after the complete combustion of volatiles. I would like to develop a
> secondary combustion zone using the energy from the flue gas after
> complete combustion, to preheat the secondary air. In simple using the
> secondary combustion energy to heat the secondary air.
>
> I think knowledge is to be share, but at the time i am working on some
> parts. As soon as I finish it i'll send it to you. I am also willing to
> see your spread sheet too.
>
> Ron:
>
> Like Crispin as soon as I finish some parts of my spread sheet, I'll send
> it to you too.
>
> Andrew,
> Thanks for your email. I am also agreed with your view that the excess
air
> doesnot affects the energy liberation as long as the FUEL IS COMPLETELY
> COMBUSTED but the thing is when you get excess air you cannot acieve
> desire temperature for complete combustion.
>
> I appololise for defining excess air in different (sometime 1.5 and
150%),
> I agree its best way to define it in equivalent ratio (excess air 150% is
> equiv ratio 2.5). Yes we need to define the optimum excess air for the
> stove for its best performance.
>
>
> kanchan

From lanny at ROMAN.NET Wed Jan 7 05:52:55 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:48 2004
Subject: 2004 Wish List
Message-ID: <WED.7.JAN.2004.055255.0500.LANNY@ROMAN.NET>

Tom,
You are under appreciated. Thanks for doing an excellent job with the
website.
About #4, content by subject areas.
A section about the foods cooked, recipes and cooking methods would be
handy if anyone needed a research project.
How about "a cook book of foods eaten in developing areas"?
If we are building stoves we need to know about the foods to be cooked.
Lanny Henson

>4. Improved presentation of content in subject ares. For example, someone
>needs to organize the data on refractory and materials of construction,
>chimneys, etc.

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 3:38 PM
Subject: [STOVES] 2004 Wish List

Stovers,

It's time to make up a wish list for what you would like to see change on
the Stoves list and website for 2004. Bear in mind that there is no budget
for anything new but a volunteer group has been working to improve the
listserv at REPP and so far REPP has been willing to support increased use
of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web.
This is in progress by the vounteer group. Archives prior to 2003 are
searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files
or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone
needs to organize the data on refractory and materials of construction,
chimneys, etc.

What are your ideas? What would make it easier to find the information you
need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 3:38 PM
Subject: [STOVES] 2004 Wish List

Stovers,

It's time to make up a wish list for what you would like to see change on
the Stoves list and website for 2004. Bear in mind that there is no budget
for anything new but a volunteer group has been working to improve the
listserv at REPP and so far REPP has been willing to support increased use
of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web.
This is in progress by the vounteer group. Archives prior to 2003 are
searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files
or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone
needs to organize the data on refractory and materials of construction,
chimneys, etc.

What are your ideas? What would make it easier to find the information you
need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

From andrew.heggie at DTN.NTL.COM Wed Jan 7 07:15:40 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:48 2004
Subject: AJH: excess air
In-Reply-To: <20040104023555.3E04BFB@telchar.epud.net>
Message-ID: <WED.7.JAN.2004.121540.0000.>

On Sat, 3 Jan 2004 18:35:53 -0800, Dean Still wrote:

>I think that we can look to increasing Turbulence (mixing) as the "big gun"
>solution to smoke. We know how to get sufficient Time (raise the height of
>the combustion chamber).

Turbulence can also achieve the Time element by causing the flame path
to increase without extra height.

> We get high enough temperatures relatively easily.
>Jets of air causing mixing gets us very close to "complete combustion", I
>think.

Turbulence should also mean that sufficient mixing takes place without
adding excess air. The reason for the mixing is to increase the chance
of fuel and oxygen molecules meeting.

AJH back to slumber mode,

From adkarve at PN2.VSNL.NET.IN Wed Jan 7 08:56:58 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: Green-Manures
Message-ID: <WED.7.JAN.2004.192658.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Peter,
Using raw sugarcane juice is a good idea. However, my statement of 10
kg sugar per acre was a simplification. There is a lot of charlatanary
in the field of organic farming. Every Guru has his own recipe. None of
them openly advocates application of sugar, but they recommend honey,
jaggery (non-centrifuged raw sugar), butter fat, etc. We conducted a few
pot experiments both with starch and sugar, and got good results. I
however suspect, that in the long run, relying just on bacteria to feed
the plants would amount to minig the soil. The bacteria can fix nitrogen
from the air, but the other minerals like P, K, Ca, Fe, and all the
other micronutrients have to come from the soil. The bacteria decompose
the soil and make these minerals available to the crop plants. So if
they are not replaced, the soils would eventually get depleted.
Yours A.D.Karve

Peter Singfield wrote:

>Dear A.D.Karve;
>
>>They provide their crops with 10 kg sugar per acre
>>instead of chemicals. I met many of them and saw their fields with my
>>own eyes. The vigour and health of their crops and the yield levels are
>>just unbelievable.
>>Yours
>>A.D.Karve
>>
>
>I suspect this is applied as a solution of sugar in water??
>
>Saying that 30% of cane juice is sugar -- then 33 kg of cane juice is
>sufficient to "fertilize" one acre.
>
>Say -- one acre of sugar cane??
>
>We suffer a terrible foreign exchange burden here to fertilize out cane
>fields at present. One thta might not be sustainable.
>
>Peter Singfield / Belize
>

From adkarve at PN2.VSNL.NET.IN Wed Jan 7 08:57:25 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: compact biogas plant
Message-ID: <WED.7.JAN.2004.192725.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Peter,
our biogas plant accepts both sugarcane juice as also macerated whole
sugarcane. In the case of the latter, the advantage is that the
cellulose in the cane is also converted into gas, albeit after a
retention period of about 20 days. The maceration is done with the help
of a machine called the chaff cutter, which is used for chopping stems
of sorghum or maize into small pieces. One can set the machine to give
different sizes of the chopped up material. We use the setting for the
smallest pieces. Under Indian conditions, where we get rains only
during the four months of monsoon, sugarcane needs irrigation.
Therefore it is not such a simple crop to grow and it is also costly.
There are many crops that produce starchy material (e.g. sorghum, pearl
millet, sweet potato and several perennial tree species). Many of them
can be grown purely under rainfed situations, and therefore starchy
material is generally cheaper. It can also be stored more easily than
sugarcane juice or sirup.
I have not patented my biogas plant as I use the same standard design.
The fact that one can get methane from starch or sugar is also not my
invention. This is common information to everybody in the biogas game.
Many people have reported high biogas yields with oilcakes. There was
however a general tendency among all workers to use only waste material
such as animal dung, municipal solid waste, distillery effluent etc. as
the raw material for making methane. All that I did was to conduct some
experiments with starchy and sugary material. When I got good results,
I started to search for such material that could be used as feedstock
without competing with human or animal food, and found that farmers
generally have a lot of starchy and sugary material, which they
considered as waste. One can of course have commercial methane
production using commercially grown starchy material such as sorghum or
tapioka. The farmer does not care for what his produce is being used
for, after he has sold it.
In fact none of our technologies is patented, as we want them to reach
the people who are need of them.
As to diversifying our operation to other areas, would certainly like to
do it, if the money is made available for it.

Yours
A.D.Karve

Peter Singfield wrote:

>At 05:58 AM 1/5/2004 +0530, A.D. Karve wrote:
>
>> Several members asked me to provide more details about the compact
>>biogas plant being developed by us. I give below the latest status of
>>this technology.
>>
>
>Dear A.D.Karve;
>
>I live in Belize, Central America, in a small village "Xaibe" -- that is
>literally surrounded in cane fields.
>
>I wonder if an optimized version of your design could be made to operate on
>only fresh cane juice??
>
>Have you tried this as of yet??
>
>For the other stovers on the list -- sugar cane is a wonderfully productive
>plant for any place in the tropics. Very easy to grow. For a large
>percentage of the world's poorest populations it is feasible to have a
>small plot of cane. This certainly would solve the "where do we find all
>the biomass to burn" problem!
>
>Certainly -- it would be of interest to me to pursue this topic further.
>
>Mr. A.D.Karve -- it is commercially impossible to ship such devices around
>the globe. But have you considered diversifying your operation to other
>areas??
>
>"Franchising" this gas producer -- based specifically on cane juice --
>would be in
>teresting and profitable.
>
>One small cane crusher in each village would suffice for everyone's gas
>generator.
>
>Though this is about gas -- and is about small stoves -- there may be a few
>on this list adverse to such a discussion being as it deals not with --
>what to date -- is considered as standard "stove".
>
>But then -- locking oneself into a rigid mind set is often counter
>productive to innovation or eventual application.
>
>By coincidence I happen to have that "one small cane crusher" --
>
>Peter Singfield
>Belize
>
>
>>
>>
>

From adkarve at PN2.VSNL.NET.IN Wed Jan 7 08:57:47 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: Small biogas plant
Message-ID: <WED.7.JAN.2004.192747.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Mr. Krenzel,
I had not given a thought to this aspect. In India, biogas plants based
on human fecal matter are being advocated by the Government as a
solution to the problem of disposing of this form of waste. All the
propaganda material generated in this connection emphasizes that the
effluent slurry coming out of such plants was devoid of pathogens and
that it could safely be used as manure, even in the case of food crops.
A.D.Karve

Art Krenzel wrote:

> Dr Karve,
>
>
>
> In an effort to reduce the hazards presented by pathogens such as E.
> Coli when using manure slurry as the initiating inoculants, it would
> be good to suggest a "clean" source of anaerobic bacteria for the
> small biogas plant. Since anaerobic conditions are well suited to
> allow pathogens to reproduce, it would be nice to have none at the
> start since the feedstocks would be clean as well.
>
>
>
> It makes the system more "user friendly".
>
>
>
> I am looking forward to your thoughts.
>
>
>
> Art Krenzel, P.E.
> PHOENIX TECHNOLOGIES
> 10505 NE 285TH Street
> Battle Ground, WA 98604
> 360-666-1883 voice
> phoenix98604@earthlink.net <mailto:phoenix98604@earthlink.net>
>

From adkarve at PN2.VSNL.NET.IN Wed Jan 7 08:58:00 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: Publication on biogas plant
Message-ID: <WED.7.JAN.2004.192800.0530.ADKARVE@PN2.VSNL.NET.IN>

I had sent longer articles on this topic to two journals, both in
India. None of them has so far published them. (A typical case of
products not being purchased, where they are grown). A detailed paper
was presented by me at a conference on biofuels, that was conducted in
October 2003 at Yogyakarta, Indonesia. We would presenting a paper at
the ETHOS conference. We had a website, ARTI-INDIA.ORG. I do not know if
it was kept alive by our office or not.
Yours A.D.Karve

Rob Williams wrote:

> Dr. Karve;
> Tom Miles cross-posted your message regarding 'compact biogas plant'.
> I found this webpage ( http://www.littlehut.org/project1/profile.asp )
> which describes your organization. Do you have any publications
> regarding small scale biogas production or is there a more detailed
> website in operation?
>
> Kind Regards,
> Rob Williams
>
>> X-Mailer: Microsoft Outlook Express 6.00.2800.1158
>> Date: Mon, 5 Jan 2004 17:00:47 -0800
>> Reply-To: Tom Miles <tmiles@TRMILES.COM>
>> Sender: The Digestion Discussion List <DIGESTION@LISTSERV.REPP.ORG>
>> From: Tom Miles <tmiles@TRMILES.COM>
>> Subject: [DIG] Compact Biogas Plant
>> To: DIGESTION@LISTSERV.REPP.ORG
>> X-Scanned-By: MIMEDefang 2.36
>> X-MIME-Autoconverted: from quoted-printable to 8bit by
>> orvieto.ucdavis.edu id i061M9mV026305
>>
>> Digestion List:The following post to the REPP Stoves Discussion List
>> ( http://listserv.repp.org/archives/stoves.html ) should be of
>> interest to those on the Digestion list. Dr. Karve is President of
>> the Appropriate Rural Technology Institute in Pune, India. I have
>> added a list of some technologies they have developed and use.Tom
>> MilesDate: Mon, 5 Jan 2004 05:58:20 +0530
>> Reply-To: "A.D. Karve" <adkarve@PN2.VSNL.NET.IN>
>> Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
>> From: "A.D. Karve" <adkarve@PN2.VSNL.NET.IN>
>> Subject: compact biogas plant
>> Content-type: text/plain; charset=us-ascii; format=flowed
>>
>> Several members asked me to provide more details about the compact
>> biogas plant being developed by us. I give below the latest status of
>> this technology.
>> The biogas plant consists of two cylindrical vessels telescoping into
>> one another. The larger vessel, called the fermenter, has a total
>> internal volume of about 500 lit. A drum having diameter of 85 cm and
>> height of 85 cm would have the desired volume. The smaller vessel, which
>> telescopes into the larger one, serves as the gas-holder. The diameter
>> of the gas holder is about 2 cm smaller than that of the fermenter. The
>> fermenter vessel is provided with appropriate inlet and outlet pipes for
>> introducing the feedstock into it and for removal of spent slurry from
>> it.
>
>
> _______________________________
>
> Robert B. Williams, PE
> Development Engineer
> Biological and Agricultural Engineering
> University of California
> One Shields Ave., Davis, CA 95616
> voice 530 752 6623
> fax 530 752 2640
> rbwilliams@ucdavis.edu
>

From adkarve at PN2.VSNL.NET.IN Wed Jan 7 08:58:20 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: Pressure cookers
Message-ID: <WED.7.JAN.2004.192820.0530.ADKARVE@PN2.VSNL.NET.IN>

The Sarai cooker is a non-pressurised stainless steel container having
the total internal capacity of about 7.5 litres. It accommodates 3
cookpots, stacked one on top of the other. One pours about 100 ml water
into the pot and then stacks the vessels with food into it, after which
it is closed with a lid. The cooker is is then placed on a charcoal
stove, which can accommodate just 100 grams of briquettes and not more.
The entire cooker and the stove assembly is enclose in a stainless steel
sleeve, in such a way, that there is gap of about 5 mm between the
cooker and the sleeve. Thus the flue gases are forced through this small
gap and they heat the cooker from all sides. The beauty of this cooker
is that once the coal has burnt itself out, the fire extinguishes
itself. The housewives just love this advantage, because they can do
other things, even go out of the house, while the food is cooking. We
have so far sold 5000 such stoves without any advertisement, and the
demand is still there. We make practically no profit on the cooker, but
once somebody has purchased our cooker he is a permanent customer for
our char briquettes.
A.D.Karve

Sobre la Roca: Energ?a Solar para el Desarrollo wrote:

>in a previous message, A.D. Karve on 1/6/04 10:49 at adkarve@PN2.VSNL.NET.IN
>wrote:
>
>>. Our Sarai
>>cooker, which is a non-pressurised cooker, has become very popular in a
>>very short time, because the food cooked in it tastes much better.
>>Incidentally, we too use a Hawkins pressure cooker in our own household!
>>A.D.Karve
>>
>Dear Dr. Karve
>Your posts are always thought provoking. Thanks.
>Could you provide details on what is your Sarai cooker, benefits, defects,
>and how it is made?
>I am looking at improved cooking vessels to be used in efficient wood,
>retained heat and solar cookers.
>Many thanks
>

From tombreed at COMCAST.NET Wed Jan 7 12:37:10 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:48 2004
Subject: Green-Manures
Message-ID: <WED.7.JAN.2004.103710.0700.TOMBREED@COMCAST.NET>

Dear Nandu and All:

It is so nice to have top world experts here ready to comment on things I
know less about.

Prof. Karve rightly says that bacteria alone can't make for rich soils.

It is my impression from thermodynamics that the clays (montmorillonite,
bentonite, ....) "lock" up the precious minerals, being the bottom of the
energy chain.

It is also my impression that volcanoes play an active part in unlocking
these minerals by melting them into more biodegradable forms. Hence the
tremendous fertility of Indonesia, Italy and Hawaii among other volcanic
terrains. I infer from this that the tremendous fertility of volcanic soils
are do to this "thermal activation" of the clays and "dead" soils.

But inference is not as desirable as knowledge, so I'm looking for
confirmation or denial or detail.

Comments?

TOM REED

----- Original Message -----
From: "A.D. Karve" <adkarve@PN2.VSNL.NET.IN>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, January 07, 2004 6:56 AM
Subject: Re: [STOVES] Green-Manures

> Dear Peter,
> Using raw sugarcane juice is a good idea. However, my statement of 10
> kg sugar per acre was a simplification. There is a lot of charlatanary
> in the field of organic farming. Every Guru has his own recipe. None of
> them openly advocates application of sugar, but they recommend honey,
> jaggery (non-centrifuged raw sugar), butter fat, etc. We conducted a few
> pot experiments both with starch and sugar, and got good results. I
> however suspect, that in the long run, relying just on bacteria to feed
> the plants would amount to minig the soil. The bacteria can fix nitrogen
> from the air, but the other minerals like P, K, Ca, Fe, and all the
> other micronutrients have to come from the soil. The bacteria decompose
> the soil and make these minerals available to the crop plants. So if
> they are not replaced, the soils would eventually get depleted.
> Yours A.D.Karve
>
>
> Peter Singfield wrote:
>
> >Dear A.D.Karve;
> >
> >>They provide their crops with 10 kg sugar per acre
> >>instead of chemicals. I met many of them and saw their fields with my
> >>own eyes. The vigour and health of their crops and the yield levels are
> >>just unbelievable.
> >>Yours
> >>A.D.Karve
> >>
> >
> >I suspect this is applied as a solution of sugar in water??
> >
> >Saying that 30% of cane juice is sugar -- then 33 kg of cane juice is
> >sufficient to "fertilize" one acre.
> >
> >Say -- one acre of sugar cane??
> >
> >We suffer a terrible foreign exchange burden here to fertilize out cane
> >fields at present. One thta might not be sustainable.
> >
> >Peter Singfield / Belize
> >

From snkm at BTL.NET Wed Jan 7 14:29:07 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:48 2004
Subject: Green-Manures
Message-ID: <WED.7.JAN.2004.132907.0600.SNKM@BTL.NET>

At 07:26 PM 1/7/2004 +0530, A.D. Karve wrote:
>>>>
Dear Peter,
Using raw sugarcane juice is a good idea. However, my statement of 10 kg
sugar per acre was a simplification. There is a lot of charlatanary in the
field of organic farming. Every Guru has his own recipe. None of them
openly advocates application of sugar, but they recommend honey, jaggery
(non-centrifuged raw sugar), butter fat, etc. We conducted a few pot
experiments both with starch and sugar, and got good results. I however
suspect, that in the long run, relying just on bacteria to feed the plants
would amount to minig the soil. The bacteria can fix nitrogen from the
air, but the other minerals like P, K, Ca, Fe, and all the other
micronutrients have to come from the soil. The bacteria decompose the soil
and make these minerals available to the crop plants. So if they are not
replaced, the soils would eventually get depleted.
Yours A.D.Karve

************************

Abstract -- replacing micro nutrients using appropriate sea weeds

Dear A. D. Karve;

Micro mineral depletion in soil is of major concern for all forms oaf
agriculture. This is a topic of interest in the US these days -- in regards
to the ultimate health consequences for people eating foods lacking in such.

Modern fertilizations procedures do not replace micro nutrients.

Sea water is the ultimate collection reservoir of all land based
micro-nutrients -- as well as minerals that are not so good for agriculture
-- such as to much salt.

I often wonder if there might not be a means of separating salt from sea
water leaving an liquid effluent low in salt -- but rich in these same
required micro-nutrients so that a readily available method of replacing
micro nutrients economically and indefinitely could be established.

The ancient Maya in my immediate area had an interesting methology for
doing exactly this -- or so I have read.

It is called raised field agriculture and was practiced in our lowlands.
The ruins of one such operation -- quite large -- being about 10 miles
North of where I now type this not.

These extensive coastal marshes were extensively channeled with canals. A
certain kind of palm trunk found here in great numbers is very resistant to
rot when in this water. So small squared sections were fenced in the marsh
lands by driving proper sized lengths into the mud.

Channels/ditches/canals where then dug surrounding each such fenced in area
-- thus raising the soil above sea level. Ergo -- raise field agriculture.

The canals were all joined to make a very efficient transport system for
logistics.

Further -- the Maya developed a specialized water plant that would absorb
minerals. And these lived happily in great density in these same canals.

Each year they harvested these weeds with long "rakes" and piled such on
their raised patches. Ergo -- replenishing the mineral content as well as
adding green manure.

Another interesting point is that every year rainy season would flood these
areas completely -- with fresh water. And also deposit rich deltas style
effluents.

The system was so efficient and so durable -- as in continuously
sustainable without outside resources -- that great population levels of
humans was achieved for a many thousands of years period.

The Ancient City State of Chetumal (which I live in among the ruins) has a
population of over 2 million people 2000 years ago and represented about
one third of the total land area of modern Belize which had problems
feeding 250,000 people these days using modern industrialized -- mechanized
-- agricultural practices!!

Further -- should global economy collapse -- and we no longer can generate
foreign exchange -- then we can grow almost nothing -- as all our
fertilizers -- insecticides and herbicides are imported.

Anyway -- is not the use of specific sea weeds as green fertilizer one
method of replacing micronutrients in a sustainable manner??

By the way -- mechanized agriculture was introduced to Belize about 20
years back -- by the Greens. They wished to stop the Mayan system of
agriculture -- called "Milpa" -- which was producing 100% organic foods by
the slash and burn of small rotating plots of land. The Greens abhor
cutting down of bush or forest.

The Greens promised that we here in Belize would be shown much better --
much easier -- ways of growing our foods at much greater yields --
mechanized agriculture.

Thus we would not need all this land -- and could give it to them for Green
Parks -- which is what happened. They now own over 54% of our total land area.

Effluents from modern mechanized agriculture -- especially in the tropics
-- where more insecticides -- and more herbicides -- of increasing toxicity
-- must be applied every year one grows in the same position -- have
reached such levels that much of our natural wild life is sickening and
dying off -- frogs -- toads -- bats -- snakes -- the reefs are become
barren of life -- and the rates of liver and lower bowel cancers has shot
up to unbelievable levels in the human population here!!

Is not modern life so wonderful -- eh?

I believe the present situation for the human species is total hopelessness
-- due to complete ignorance.

However -- if the US can start the next world war fast enough -- their is
hope for us here in Belize that we still can return to traditional life
styles -- ergo -- these questions above are still valid.

For those on this list living in the modern industrialized nations -- there
is no hope whatever.

On the other hand -- being as the per capita use of petroleum products in
the US is 8000 gallons per person per year -- their self extermination
(along with the rest of industrialized human kind) could mean new life for
the planet.

So we pray America gets on quickly with bringing the entire globe to war of
the worse kind -- "bring them on" -- eh???

Peter -- in Belize -- in the twilight of this turn of the wheel.

From lanny at ROMAN.NET Wed Jan 7 18:49:59 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:48 2004
Subject: Pressure cookers
Message-ID: <WED.7.JAN.2004.184959.0500.LANNY@ROMAN.NET>

Dear Dr Karve,
Thanks for sharing the details of your Sarai Cooker. The outer container and
3 inner cook pots with steam conducting the heat is brilliant.
And only using only 100 grams of charcoal is amazing.
One thing that I do not understand is how do you get a clean burn with such
a thin layer of charcoal. I was thinking that in order to get charcoal hot
enough to burn CO to CO2 you had to stack it in a column or blast it with
high velocity supply air. So how is the CO output?
Only 100 grams of charcoal may not be enough to be a problem even in the
worst scenario. Are the stoves safe inside?
Lanny Henson

----- Original Message -----
From: A.D. Karve <adkarve@PN2.VSNL.NET.IN>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, January 07, 2004 8:58 AM
Subject: Re: [STOVES] Pressure cookers

> The Sarai cooker is a non-pressurised stainless steel container having
> the total internal capacity of about 7.5 litres. It accommodates 3
> cookpots, stacked one on top of the other. One pours about 100 ml water
> into the pot and then stacks the vessels with food into it, after which
> it is closed with a lid. The cooker is is then placed on a charcoal
> stove, which can accommodate just 100 grams of briquettes and not more.
> The entire cooker and the stove assembly is enclose in a stainless steel
> sleeve, in such a way, that there is gap of about 5 mm between the
> cooker and the sleeve. Thus the flue gases are forced through this small
> gap and they heat the cooker from all sides. The beauty of this cooker
> is that once the coal has burnt itself out, the fire extinguishes
> itself. The housewives just love this advantage, because they can do
> other things, even go out of the house, while the food is cooking. We
> have so far sold 5000 such stoves without any advertisement, and the
> demand is still there. We make practically no profit on the cooker, but
> once somebody has purchased our cooker he is a permanent customer for
> our char briquettes.
> A.D.Karve
>
> Sobre la Roca: Energ?a Solar para el Desarrollo wrote:
>
> >in a previous message, A.D. Karve on 1/6/04 10:49 at
adkarve@PN2.VSNL.NET.IN
> >wrote:
> >
> >>. Our Sarai
> >>cooker, which is a non-pressurised cooker, has become very popular in a
> >>very short time, because the food cooked in it tastes much better.
> >>Incidentally, we too use a Hawkins pressure cooker in our own household!
> >>A.D.Karve
> >>
> >Dear Dr. Karve
> >Your posts are always thought provoking. Thanks.
> >Could you provide details on what is your Sarai cooker, benefits,
defects,
> >and how it is made?
> >I am looking at improved cooking vessels to be used in efficient wood,
> >retained heat and solar cookers.
> >Many thanks
> >
>

From lanny at ROMAN.NET Wed Jan 7 19:04:29 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:48 2004
Subject: compact biogas plant
Message-ID: <WED.7.JAN.2004.190429.0500.LANNY@ROMAN.NET>

When using grain is the protein broken down or is it preserved in the
slurry?
Lanny Henson

> considered as waste. One can of course have commercial methane
> production using commercially grown starchy material such as sorghum or
> tapioka. The farmer does not care for what his produce is being used
> for, after he has sold it.

----- Original Message -----
From: A.D. Karve <adkarve@PN2.VSNL.NET.IN>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, January 07, 2004 8:57 AM
Subject: Re: [STOVES] compact biogas plant

> Dear Peter,
> our biogas plant accepts both sugarcane juice as also macerated whole
> sugarcane. In the case of the latter, the advantage is that the
> cellulose in the cane is also converted into gas, albeit after a
> retention period of about 20 days. The maceration is done with the help
> of a machine called the chaff cutter, which is used for chopping stems
> of sorghum or maize into small pieces. One can set the machine to give
> different sizes of the chopped up material. We use the setting for the
> smallest pieces. Under Indian conditions, where we get rains only
> during the four months of monsoon, sugarcane needs irrigation.
> Therefore it is not such a simple crop to grow and it is also costly.
> There are many crops that produce starchy material (e.g. sorghum, pearl
> millet, sweet potato and several perennial tree species). Many of them
> can be grown purely under rainfed situations, and therefore starchy
> material is generally cheaper. It can also be stored more easily than
> sugarcane juice or sirup.
> I have not patented my biogas plant as I use the same standard design.
> The fact that one can get methane from starch or sugar is also not my
> invention. This is common information to everybody in the biogas game.
> Many people have reported high biogas yields with oilcakes. There was
> however a general tendency among all workers to use only waste material
> such as animal dung, municipal solid waste, distillery effluent etc. as
> the raw material for making methane. All that I did was to conduct some
> experiments with starchy and sugary material. When I got good results,
> I started to search for such material that could be used as feedstock
> without competing with human or animal food, and found that farmers
> generally have a lot of starchy and sugary material, which they
> considered as waste. One can of course have commercial methane
> production using commercially grown starchy material such as sorghum or
> tapioka. The farmer does not care for what his produce is being used
> for, after he has sold it.
> In fact none of our technologies is patented, as we want them to reach
> the people who are need of them.
> As to diversifying our operation to other areas, would certainly like to
> do it, if the money is made available for it.
>
> Yours
> A.D.Karve
>
> Peter Singfield wrote:
>
> >At 05:58 AM 1/5/2004 +0530, A.D. Karve wrote:
> >
> >> Several members asked me to provide more details about the compact
> >>biogas plant being developed by us. I give below the latest status of
> >>this technology.
> >>
> >
> >Dear A.D.Karve;
> >
> >I live in Belize, Central America, in a small village "Xaibe" -- that is
> >literally surrounded in cane fields.
> >
> >I wonder if an optimized version of your design could be made to operate
on
> >only fresh cane juice??
> >
> >Have you tried this as of yet??
> >
> >For the other stovers on the list -- sugar cane is a wonderfully
productive
> >plant for any place in the tropics. Very easy to grow. For a large
> >percentage of the world's poorest populations it is feasible to have a
> >small plot of cane. This certainly would solve the "where do we find all
> >the biomass to burn" problem!
> >
> >Certainly -- it would be of interest to me to pursue this topic further.
> >
> >Mr. A.D.Karve -- it is commercially impossible to ship such devices
around
> >the globe. But have you considered diversifying your operation to other
> >areas??
> >
> >"Franchising" this gas producer -- based specifically on cane juice --
> >would be in
> >teresting and profitable.
> >
> >One small cane crusher in each village would suffice for everyone's gas
> >generator.
> >
> >Though this is about gas -- and is about small stoves -- there may be a
few
> >on this list adverse to such a discussion being as it deals not with --
> >what to date -- is considered as standard "stove".
> >
> >But then -- locking oneself into a rigid mind set is often counter
> >productive to innovation or eventual application.
> >
> >By coincidence I happen to have that "one small cane crusher" --
> >
> >Peter Singfield
> >Belize
> >
> >
> >>
> >>
> >
>

From tmiles at TRMILES.COM Thu Jan 8 23:49:44 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:48 2004
Subject: [ethos] tentative ethos 2004 conference schedule
Message-ID: <THU.8.JAN.2004.204944.0800.TMILES@TRMILES.COM>

Mark,

Quite a full program.

What are your thoughts about "Break Out Groups and Committee Meetings". Are
you thinking about the comittees that were defined last year or a new set of
groups/committees?

Thanks

Tom

----- Original Message -----
From: "Mark Bryden" <kmbryden@iastate.edu>
To: <ethos@vrac.iastate.edu>; <STOVES@LISTSERV.REPP.ORG>
Cc: "Amy Holland" <aholland@iastate.edu>; <gxo2@po.cwru.edu>
Sent: Thursday, January 08, 2004 6:13 PM
Subject: [ethos] tentative ethos 2004 conference schedule

> Friends,
>
> Attached is the tentative schedule for the upcoming ETHOS 2004 Conference
> in both .doc and acrobat .pdf format. Both documents are identical and so
> as long as you can read one you should be ok. In the next day or two this
> information will also be posted on the web at
> http://www.vrac.iastate.edu/~kmbryden/ethos.htm
> Also directions for travel to conference venue and other important
> information will be available at this web address.
>
> As you will note we have an exciting set of talks, workshops, a poster
> session, and a slide show. Following the conference there will be the
> Stoves Workshop sponsored by the US EPA and others. I am very impressed by
> the breadth of countries, organizations, and skills that will be
> represented and I am sure that you will be too.
>
> A couple of requests:
> 1) Please check to make sure that your talk is on the schedule and that
the
> title etc is correct. Any corrections or additions please let me know as
> soon as possible. If your talk is missing please let me know and if you
are
> no longer able to attend please let me know so that we can use that slot
> for another talk.
> 2) We will be running very close to the capacity of the room that we have
> scheduled for this event. Because of this we need you to preregister so
> that we can ensure that we are able to seat everyone who would like to
> attend. Prepayment of the $35 registration fee is not required only
> preregistration. I will be sending out the preregistration form in the
next
> day or two.
>
> I look forward to seeing many of you at the conference.
>
> Mark
>
> ___________________________________________________________
> Kenneth "Mark" Bryden, Ph.D. Assistant Professor
> kmbryden@iastate.edu Iowa State University
> ph: 515-294-3891 3030 Black Engineering Bldg
> fax: 515-294-3261 Ames, Iowa 50011-2161
>

From dstill at EPUD.NET Fri Jan 9 00:55:55 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:48 2004
Subject: Directions to ETHOS/PCIA Conference/Hotel
Message-ID: <THU.8.JAN.2004.215555.0800.DSTILL@EPUD.NET>

Dear ETHOS/PCIA Conference Attendees,

There is a block of rooms reserved under the name of ETHOS/PCIA at:

The BEST WESTERN KIRKLAND INN

12223NE 116th Street

Kirkland, Washington 98034

(425) 822-2300

For reservations please call:

1-800-332-4200

The cost is $68 plus tax for two per night. $64 plus tax for a single.

Shuttle Express provides shuttle service from the Seattle/Tacoma airport on
a scheduled basis many times per day. Reservations are necessary for the
shuttle service. The cost is $21 for the first adult, $10 for the second and
$6 for each additional passenger. Let?s travel together! Call
1-800-487-7433 or 425-981-7000.

A large private car with driver that accommodates 4 passengers is available
for $60. Call Express Car at 1-800-324-9277 0r 425-981-7077. Reservations
must be made in advance. Service from airport to hotel.

For those driving:

NORTHBOUND

Driving North on I-405

Exit 20A (116th Street)

Right at light.

Right at Brown Bag Caf?.

Inn is located behind the Caf?.

SOUTHBOUND

Driving South on I-405

Exit 20 (1234th Street)

Right at light. Immediate left at next light (120th)

Left on 116th through next light.

Right at Brown Bag Caf?.

Inn is located behind the Caf?.

From larryw at PROAXIS.COM Fri Jan 9 01:52:03 2004
From: larryw at PROAXIS.COM (larry winiarski)
Date: Tue Aug 10 18:30:48 2004
Subject: [ethos] tentative ethos 2004 conference schedule
Message-ID: <THU.8.JAN.2004.225203.0800.LARRYW@PROAXIS.COM>

Hi Mark.

I plan to present a talk on " Various Applications of the Rocket Stove
Priinciples"
Dean suggested that this could be done in the time slot listed for panel
discussion and talks.

I would also like to show more of my most recent applications including
a big coffee husk burner in Rwanda Africa during the evening slide show

God Bless

Larry

From adkarve at PN2.VSNL.NET.IN Fri Jan 9 08:28:40 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: compact biogas plant
Message-ID: <FRI.9.JAN.2004.185840.0530.ADKARVE@PN2.VSNL.NET.IN>

Everything that humans can digest is digested easily and within a
relatively short time by the biogas bacteria. Proteins are in fact
needed as nutrition by the bacteria. Oilseed cake, which is very rich
in proteins, yields much more methane than grain flour, but continuous
use of oilseed cake alone may poison the system, because under anaerobic
conditions the nitrogen gets converted into ammonia and sulphur into
hydrogen sulphide. The text books say that a certain C/N ratio is
required to get good gas generation. So one has to find the right
proportion of starch to protein. Whole seeds of most plants represent
complete nutrition for a living being.We have tested homogenised whole
kernels of two oilseeed species, namely Pongamia pinnata and castor, in
long term experiments, without any fouling up.
A.D.Karve

Lanny Henson wrote:

>When using grain is the protein broken down or is it preserved in the
>slurry?
>Lanny Henson
>
>>considered as waste. One can of course have commercial methane
>>production using commercially grown starchy material such as sorghum or
>>tapioka. The farmer does not care for what his produce is being used
>>for, after he has sold it.
>>
>
>----- Original Message -----
>From: A.D. Karve <adkarve@PN2.VSNL.NET.IN>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Wednesday, January 07, 2004 8:57 AM
>Subject: Re: [STOVES] compact biogas plant
>
>
>> Dear Peter,
>>our biogas plant accepts both sugarcane juice as also macerated whole
>>sugarcane. In the case of the latter, the advantage is that the
>>cellulose in the cane is also converted into gas, albeit after a
>>retention period of about 20 days. The maceration is done with the help
>>of a machine called the chaff cutter, which is used for chopping stems
>>of sorghum or maize into small pieces. One can set the machine to give
>>different sizes of the chopped up material. We use the setting for the
>>smallest pieces. Under Indian conditions, where we get rains only
>>during the four months of monsoon, sugarcane needs irrigation.
>> Therefore it is not such a simple crop to grow and it is also costly.
>>There are many crops that produce starchy material (e.g. sorghum, pearl
>>millet, sweet potato and several perennial tree species). Many of them
>>can be grown purely under rainfed situations, and therefore starchy
>>material is gen
>>erally cheaper. It can also be stored more easily than
>>sugarcane juice or sirup.
>>I have not patented my biogas plant as I use the same standard design.
>>The fact that one can get methane from starch or sugar is also not my
>>invention. This is common information to everybody in the biogas game.
>>Many people have reported high biogas yields with oilcakes. There was
>>however a general tendency among all workers to use only waste material
>>such as animal dung, municipal solid waste, distillery effluent etc. as
>>the raw material for making methane. All that I did was to conduct some
>>experiments with starchy and sugary material. When I got good results,
>>I started to search for such material that could be used as feedstock
>>without competing with human or animal food, and found that farmers
>>generally have a lot of starchy and sugary material, which they
>>considered as waste. One can of course have commercial methane
>>production using commercially
>> grown starchy material such as sorghum or
>>tapioka. The farmer does not care for what his produce is being used
>>for, after he has sold it.
>>In fact none of our technologies is patented, as we want them to reach
>>the people who are need of them.
>>As to diversifying our operation to other areas, would certainly like to
>>do it, if the money is made available for it.
>>
>>Yours
>>A.D.Karve
>>
>>Peter Singfield wrote:
>>
>>>At 05:58 AM 1/5/2004 +0530, A.D. Karve wrote:
>>>
>>>>Several members asked me to provide more details about the compact
>>>>biogas plant being developed by us. I give below the latest status of
>>>>this technology.
>>>>
>>>Dear A.D.Karve;
>>>
>>>I live in Belize, Central America, in a small village "Xaibe" -- that is
>>>literally surrounded in cane fields.
>>>
>>>I wonder if an optimized version of your design could be made to operate
>>>
>on
>
>>>only fresh cane juice??
>>>
>>>Have you tried this as of yet??
>>>
>>>For the other stovers on the list -- sugar cane is a wonderfully
>>>
>productive
>
>>>plant for any place in the tropics. Very easy to grow. For a large
>>>percentage of the world's poorest populations it is feasible to have a
>>>small plot of cane. This certainly would solve the "where do we find all
>>>the biomass to burn" problem!
>>>
>>>Certainly -- it would be of interest to me to pursue this topic further.
>>>
>>>Mr. A.D.Karve -- it is commercially impossible to ship such devices
>>>
>around
>
>>>the globe. But have you considered diversifying your operation to other
>>>areas??
>>>
>>>"Franchising" this gas producer -- based specifically on cane juice --
>>>would be in
>>>teresting and profitable.
>>>
>>>One small cane crusher in each village would suffice for everyone's gas
>>>generator.
>>>
>>>Though this is about gas -- and is about small stoves -- there may be a
>>>
>few
>
>>>on this list adverse to such a discussion being as it deals not with --
>>>what to date -- is considered as standard "stove".
>>>
>>>But then -- locking oneself into a rigid mind set is often counter
>>>productive to innovation or eventual application.
>>>
>>>By coincidence I happen to have that "one small cane crusher" --
>>>
>>>Peter Singfield
>>>Belize
>>>
>>>
>>>>
>
>
>

From adkarve at PN2.VSNL.NET.IN Fri Jan 9 08:34:35 2004
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:48 2004
Subject: Gasifier Charcoal and clean water
Message-ID: <FRI.9.JAN.2004.190435.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Tom, Ray and Darren,
bamboo charcoal, even when made in ordinary charcoal kilns, has
astonishing absorbant properties. Somebody gave us a specimen for
estimating its calorific value and we found that just while weighing the
powdered charcoal, its weight kept increasing due to absorption of
moisture from the atmosphere.
I am also a member of a discussion group on bamboo, and there are often
reports about bamboo charcoal being used as active charcoal. There was
a report that bamboo charcoal kept in a refrigerator, deodorized the
refrigerator. In our Institute we have a group of people working on
bamboo. They use bamboo for construction of various structures. Because
of this activity we have finished all the bamboo in our vicinity. Now
we are persuading farmers to grow bamboo as a regular crop. Active
charcoal sells at three times the cost of normal charcoal. Therefore,
if ordinary bamboo charcoal were to have the same properties as active
charcoal, farmers can earn a lot of money by converting their bamboo
into charcoal.
A.D.Karve

TBReed wrote:

>Dear Darren, Shelton and All:
>
>Glad to see Darren's numbers. We have also measured iodine numbers on
>gasifier carbon and find ~200, depending on intensity of operation of the
>gasifier. This is NOT a commercial grade of activated carbon, but might
>have some uses.
>
>To produce activated carbon it is necessary for the carbon to be made porous
>by reaction with CO2, Steam or chemicals in the temperature range 700-900C
>where the kinetics of carbon gasification . Lower than that there is no
>reaction, and at higher temperatures the reaction is controlled by mass flow
>rather than kinetically controlled.
>
>I have been interested in the possibility of using gasifiers for water
>purification in the poorer parts of the world. Electric power from gasifiers
>would give enough power to operate an ozone generator for killing
>pathogens - more desirable than chlorine treatment. And the char-dust from
>the gasifier could be used t
>o remove the large brown molecules that discolor
>slower moving water. Possibly the gasifier charcoal can fill this use,
>having 1/5 the absorbtion capacity of "activated" charcoal.
>
>Comments?
>
>TOM REED
>
>----- Original Message -----
>From: "Schmidt, Darren" <dschmidt@UNDEERC.ORG>
>To: <GASIFICATION@LISTSERV.REPP.ORG>
>Sent: Wednesday, January 07, 2004 7:21 AM
>Subject: Re: [GASL] AC
>
>
>>The most common method I am aware of is an Iodine # test. A good active
>>carbon will be about 1000. We have found that carbon from air fed
>>
>downdraft
>
>>gasification is about 250.
>>
>>D. Schmidt
>>EERC
>>University of North Dakota
>>
>>-----Original Message-----
>>From: shelton victor [mailto:sheltonvictor@YAHOO.CO.IN]
>>Sent: Wednesday, January 07, 2004 7:26 AM
>>To: GASIFICATION@LISTSERV.REPP.ORG
>>Subject: [GASL] AC
>>
>>
>>hello
>>
>>i have problem in evaluating the activated carbon that i have produced
>>using fluidized bed gasification is there a simple method to detemine its
>>quality.
>>
>>Yahoo! India Mobile: Ringtones, Wallpapers, Picture Messages and
>>more.Download now.
>>
>
>

From danacharron at YAHOO.COM Fri Jan 9 13:25:06 2004
From: danacharron at YAHOO.COM (Dana Harmon Charron)
Date: Tue Aug 10 18:30:48 2004
Subject: 2004 Wish List
In-Reply-To: <009c01c3d50c$7600e5c0$9b387f41@oemcomputer>
Message-ID: <FRI.9.JAN.2004.102506.0800.>

Tom,

I agree with Lanny that you are doing a wonderful job. The stoves list and
site are a wonderful resource. (I know you didn't post this to solicit
kudos, but that's what I have to contribute at the moment.)

--Dana

Dana Charron
CEIHD-Household Energy and Health
510-547-4036
dana@ceihd.com
http://ceihd.berkeley.edu

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG] On Behalf
Of Lanny Henson
Sent: Wednesday, January 07, 2004 2:53 AM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] 2004 Wish List

>4. Improved presentation of content in subject ares. For example,
>someone needs to organize the data on refractory and materials of
>construction, chimneys, etc.

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 3:38 PM
Subject: [STOVES] 2004 Wish List

Stovers,

It's time to make up a wish list for what you would like to see change on
the Stoves list and website for 2004. Bear in mind that there is no budget
for anything new but a volunteer group has been working to improve the
listserv at REPP and so far REPP has been willing to support increased use
of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web.
This is in progress by the vounteer group. Archives prior to 2003 are
searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files
or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone
needs to organize the data on refractory and materials of construction,
chimneys, etc.

What are your ideas? What would make it easier to find the information you
need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 3:38 PM
Subject: [STOVES] 2004 Wish List

Stovers,

It's time to make up a wish list for what you would like to see change on
the Stoves list and website for 2004. Bear in mind that there is no budget
for anything new but a volunteer group has been working to improve the
listserv at REPP and so far REPP has been willing to support increased use
of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web.
This is in progress by the vounteer group. Archives prior to 2003 are
searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files
or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone
needs to organize the data on refractory and materials of construction,
chimneys, etc.

What are your ideas? What would make it easier to find the information you
need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

---
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From tmiles at TRMILES.COM Sat Jan 10 01:28:48 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:48 2004
Subject: 2004 Wish List
Message-ID: <SAT.10.JAN.2004.012848.0500.TMILES@TRMILES.COM>

Dana,

Thank you for your kind comments.

One of our ETHOS goals last year was to find ways to fund more health
studies of operating stoves in household settings. Except for Rob Bailis'
ES&T article last Spring I'm afraid I haven't added much to the "Health
and Environmental Risks" section of the site toward this goal. I'd be
grateful for any links or papers that you may have to offer.

I look forward to seeing you in Seattle.

Kind regards,

Tom

On Fri, 9 Jan 2004 10:25:06 -0800, Dana Harmon Charron
<danacharron@YAHOO.COM> wrote:

>Tom,
>
>I agree with Lanny that you are doing a wonderful job. The stoves list
and
>site are a wonderful resource. (I know you didn't post this to solicit
>kudos, but that's what I have to contribute at the moment.)
>
>--Dana
>
>Dana Charron
>CEIHD-Household Energy and Health
>510-547-4036
>dana@ceihd.com
>http://ceihd.berkeley.edu

From kmbryden at IASTATE.EDU Sat Jan 10 12:08:37 2004
From: kmbryden at IASTATE.EDU (Mark Bryden)
Date: Tue Aug 10 18:30:48 2004
Subject: tentative Ethos 2004 conference schedule
Message-ID: <SAT.10.JAN.2004.110837.0600.KMBRYDEN@IASTATE.EDU>

Friends,

Given in text below is the tentative schedule for the upcoming ETHOS 2004
Conference in Seattle, Washington USA. This information is also be posted
on the web in .pdf and .doc format at
http://www.vrac.iastate.edu/~kmbryden/ethos.htm

As you will note we have an exciting set of talks, workshops, a poster
session, and a slide show. Following the conference there will be the
Stoves Workshop sponsored by the US EPA and others. I am very impressed by
the breadth of countries, organizations, and skills that will be
represented and I am sure that you will be too.

A couple of requests:
1) Please check to make sure that your talk is on the schedule and that the
title etc is correct. Any corrections or additions please let me know as
soon as possible. If your talk is missing please let me know and if you are
no longer able to attend please let me know so that we can use that slot
for another talk.
2) We will be running very close to the capacity of the room that we have
scheduled for this event. Because of this we need you to preregister so
that we can ensure that we are able to seat everyone who would like to
attend. Prepayment of the $35 registration fee is not required only
preregistration. I will be sending out the preregistration form in the next
day or two.

Also directions for travel to conference venue and other important
information will be available at this web address. The specific location of
the conference will be at Northwest College in Kirkland Washington on the
east side of Seattle. If you are flying, you will want to fly to Seatac
airport (SEA). From there you can rent a car or ground transportation to
the conference hotel is available. You should have received travel
directions from Dean Still yesterday. Directions from the hotel to the
conference venue will be available at the conference hotel.

I look forward to seeing many of you at the conference.

Mark

-------------------------------------------------------------------------------------------------------
ETHOS 2004 Conference Tentative Schedule

Saturday, January 31, 2004

7:30 - 8:00 Registration

8:00 - 8:15 Welcome and Introductions Mark Bryden and
Dean Still

8:15 - 9:15 ETHOS in the past year and Committee Reports (2
slides/committee)

9:15 - 10:00 Generating Global Results to Improve Stoves and Fuels

Brenda Doroski, US EPA, Join with the Partnership for Clean Indoor Air to
Eliminate Smoke in Homes

Karen Westley, Shell Foundation, Challenges and Lessons in
Commercialization of Improved Stoves and Fuels

Simone Lawaetz (not confirmed), USAID

10:00 - 10:15 Break

10:15 - 11:45 Improving Stove Testing and Design: Efficiency,
Effectiveness, Emissions and Safety

Dean Still and Damon Ogle, New Boiling Water Test

Mark Bryden, Stove Safety: Some Thoughts and Proposed Guidelines

Dale Andreatta, Thermal Properties of Insulative Brick

Dana Charron (not confirmed) Nicaragua IAP Testing

Tami Bond Monitoring Stove Emissions

Dan Kammen

11:45 - 1:00 Lunch (on your own - walk to the campus cafeteria)

1:00 - 1:45 Cooking Technologies: Thoughts, Ideas, and Proposed Solutions

Priya Karve - Design and Field Testing of a Compact Biogas Plant

Wilfred and Marie Pimentel Integrated Cooking

Tom Reed Gasification Stoves

Harry Stokes - The Promise of Alcohol Fuels in Africa: A New Rung on the
Energy Ladder

Rogerio de Miranda

1:45 - 3:15 Stove Design and Analysis: Talks and Panel Discussion

K. Prasad

Piet Visser

Peter Verhaart

Larry Winiarski Various Applications of the Rocket Stove Principles

3:15 - 3:30 Break

3:30 - 4:00 Poster Session Introductions (1 slide/3 minutes each)

4:00 - 5:30 Poster Session

Dar Curtis

Dale Andreatta, Cookstove Pollutant Output Measurement

Paul Anderson, Small Gasifier Stoves--Advances in Africa

Tom Miles , The Stove List

Dean Still

Mark Bryden and Doug McCorkle, Stove Design and Optimization

Susil Liyanarachchi, Energy and Street Food

Margie Pinnell

Lisa B?ttner

Others who have expressed interest but not yet committed

5:30 - 7:30 Dinner (at the college cafeteria if available)

7:30 - 9:30 Slide Shows

Peter Scott Uganda, S. Africa--bread oven, new designs

Rogerio Miranda, New Stove Enterprise, Designs in Brazil

Larry Winiarski Coffee Husk Burner in Rwanda, Africa

David Whitfield ,

Peter Verhart Down Draft Barbeque

Stuart Conway

Don O?Neal

Sambandam Sankar (not confirmed)

Swedi Elongo (not confirmed)

Rajan Thapa (not confirmed)

Sunday, February 1, 2004

8:00 -10:00 Implementing Stove Programs: Talks and Discussion Panel

A. D. Karve

Don O?Neal and Richard Grinnell Mass-production of the HELPS Stove in
Guatemala

Stuart Conway Honduras Micro-Enterprise Stove Project

Omar Masera

Lisa Buttner Exploring the integration of household energy into the
Alliance for Mindanao Off-grid Rural Electrification project

Ganesh Shrestha Experiences in the Promotion and Transfer of Improved
Cooking Stove Technologies in Nepal

Choppalli Venkata Krishna (not confirmed) Improved Cookstoves: Yet to be
a Success

10:00 -10:15 Break

10:15 -11:30 Break Out Groups and Committee Meetings

11:30 -12:30 Lunch (on your own - walk to the campus cafeteria)

12:30 - 1:00 Committee Reports

1:00 - 2:30 Outline plans for next year

2:30 - 5:00 Stoves Demonstration

___________________________________________________________
Kenneth "Mark" Bryden, Ph.D. Assistant Professor
kmbryden@iastate.edu Iowa State University
ph: 515-294-3891 3030 Black Engineering Bldg
fax: 515-294-3261 Ames, Iowa 50011-2161

From Kanchan at KU.EDU.NP Mon Jan 12 15:17:44 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:30:48 2004
Subject: Excess air
Message-ID: <TUE.13.JAN.2004.020244.0545.KANCHAN@KU.EDU.NP>

Dear Andrew, You wrote on 6th jan 04

>I agree, but how do you propose to do it without a fan or chimney?

My idea is pretty rough and may sound silly too. But what I think,
particularty for metal stove, pressure difference will make this possible.
For this, CHIMNEY is very essential. When volatiles (from primary
combustion) burns at the secondary combustion zone , the flue leaves
through chimney and there will be pressure drop inside combustion chamber.
If we possible to design such a way that all the primary air is completely
consumed at the primary combustion zone and there is no other way to
balance the pressure difference (in secondary combustion zone) apart from
secondary air, I guess it will work. My Idea is to use primary air only to
control the burning rate and rest (complete combustion) by secondary air.

I have an idea in which everything in my calculation looks fine but only
thing worried me is at one point secondary air have to flow downwwards. As
we know hot air will tend to move upward. Now its upon the pressure
difference inside secondary chamber and atmosphere and the hot air flowing
downward, I am very much like to see which will win but here with me is
very little equipements to work with. Do you ( all stovers) have any idea
to measure the negative pressure inside hot combustion chamber (above
800C)?

kanchan

From tombreed at COMCAST.NET Mon Jan 12 08:54:03 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:49 2004
Subject: compact biogas plant
Message-ID: <MON.12.JAN.2004.065403.0700.TOMBREED@COMCAST.NET>

Dear Nandu:

Congratulations on moving the digestor off of the farm and into the
home/basement. Methane is a marvelous fuel for cooking and the requirement
is not too large.

Is this your invention? Whether you invented it or not, you are in a
position to move it to those who ineed it faster than anyone I know. I
believe that there is a BIOGAS site here at REPP and you should post equally
to them.

Not all of us have 10 cows to generate the gas for our family, but starches
and sugars are widely available.

You said that 1 kg of sugar (or starch) yields 400 liters of methane. The
chemistry of this reaction is approximately

C6H12O6 (sugars) ===> 3CO2 + 3 CH4

a disproportionation reaction giving equal volumes of the two gases. ( I can
work out the heat of reaction if you wish, but it will be small.)

The other new twist you have added to the biogas producer is diffusion of
the CO2 out of the system. I presume this is time dependent, so relying on
it would give varying gas quality as diffusion is a slow process. You might
consider putting wood ash or another alkali into the water to absorb the CO2
to a carbonate ion. Or you might seal the system and keep the 50% CO2 which
doesn't hurt the combustion of heat generation.

Anyhow, whatever, its a major step toward renewable energy.

Yours truly, TOM REED THE BIOMASS ENERGY
FOUNDATION
----- Original Message -----
From: "A.D. Karve" <adkarve@PN2.VSNL.NET.IN>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 5:28 PM
Subject: [STOVES] compact biogas plant

From K.Prasad at TUE.NL Tue Jan 13 06:31:50 2004
From: K.Prasad at TUE.NL (Prasad, K.)
Date: Tue Aug 10 18:30:49 2004
Subject: 2004 Wish List
Message-ID: <TUE.13.JAN.2004.123150.0100.K.PRASAD@TUE.NL>

Dear Lanny and other stovers

A "cookbook of foods eaten in developing areas" is an excellent idea. I'm
sure my former colleagues Pete Verhaart and Piet Visser and myself could
contribute to such a book.
Needless to say, similar effort on refractories, materials of construction,
and chimneys would also be very useful. Pete Verhaart and Piet visser are
genuine Mechanical nengineers unlike me, the phoney one, could contribute to
this effort.

Sorry Pete and Piet dragging your names like this.

Yours
Prasad

-----Original Message-----
From: Lanny Henson [mailto:lanny@ROMAN.NET]
Sent: Wednesday, January 07, 2004 11:53 AM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] 2004 Wish List

>4. Improved presentation of content in subject ares. For example, someone
>needs to organize the data on refractory and materials of construction,
>chimneys, etc.

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 3:38 PM
Subject: [STOVES] 2004 Wish List

Stovers,

It's time to make up a wish list for what you would like to see change on
the Stoves list and website for 2004. Bear in mind that there is no budget
for anything new but a volunteer group has been working to improve the
listserv at REPP and so far REPP has been willing to support increased use
of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web.
This is in progress by the vounteer group. Archives prior to 2003 are
searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files
or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone
needs to organize the data on refractory and materials of construction,
chimneys, etc.

What are your ideas? What would make it easier to find the information you
need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

----- Original Message -----
From: Tom Miles <tmiles@TRMILES.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, January 04, 2004 3:38 PM
Subject: [STOVES] 2004 Wish List

Stovers,

It's time to make up a wish list for what you would like to see change on
the Stoves list and website for 2004. Bear in mind that there is no budget
for anything new but a volunteer group has been working to improve the
listserv at REPP and so far REPP has been willing to support increased use
of space on the website.

Ideas for the list:
http://listserv.repp.org/archives/stoves.html

1. Current stoves archives (since 2002) should be searchable on the web.
This is in progress by the vounteer group. Archives prior to 2003 are
searchable via Google and other search engines.

2. Improved listserver. This is also being worked on by the volunteer group.

Ideas for the Web site:
http://www.repp.org/discussiongroups/resources/stoves/

1. Easier navigation.
2. References or bibliography section.
3. Site for electronic pre-prints, where list member can post images, files
or papers for review by others.
4. Improved presentation of content in subject ares. For example, someone
needs to organize the data on refractory and materials of construction,
chimneys, etc.

What are your ideas? What would make it easier to find the information you
need or present your ideas? Or are we doing just fine?

Thanks for your help.

Tom Miles
tmiles@trmiles.com

From K.Prasad at TUE.NL Tue Jan 13 06:57:03 2004
From: K.Prasad at TUE.NL (Prasad, K.)
Date: Tue Aug 10 18:30:49 2004
Subject: Chimneys
Message-ID: <TUE.13.JAN.2004.125703.0100.K.PRASAD@TUE.NL>

Dear Tom

Should it not be "THE BEST IS THE ENEMY OF THE GOOD"

I always thought engineering was about compromises (mathematically speaking
"optimization")and the best quite often ignores the price one pays for
achieving it.

Yours
Prasad

-----Original Message-----
From: TBReed [mailto:tombreed@COMCAST.NET]
Sent: Sunday, January 04, 2004 3:34 PM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Chimneys

Dear Das and All:

I second all of Das's comments, but would like to add a few more on
chimneys.

The chimney is a good solution to combustion, but often

"THE GOOD IS THE ENEMY OF THE BEST".

The need to discard the combustion gases at a high enough temperature to
maintain good draft (say 400 C? - comment?) Means that you are limiting
heat recovery to

(Tc-Td)/Tc

(where Tc is the combustion temperature, Td is the draft temperature)

Today it is relatively easy and inexpensive to put an oxygen (lambda) sensor
on a stack and monitor the stoichiometry which then controls combustion
temperature and efficiency.

~~~~~~~
This efficiency loss is a high penalty for using a thermal draft. You can
avoid it for biomass fuels by using a forced draft system and more precisely
controlling the combustin conditions.

~~~~~~~
So we will all continue to use chimneys as as a practical solution to draft,
but keeping in mind that there is much better technology available when the
price is right.

Onward,

TOM REED

----- Original Message -----
From: "Das" <das@EAGLE-ACCESS.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, January 02, 2004 2:29 PM
Subject: Re: [STOVES] Chimneys

From kchisholm at CA.INTER.NET Tue Jan 13 08:59:03 2004
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:49 2004
Subject: Chimneys
Message-ID: <TUE.13.JAN.2004.095903.0400.KCHISHOLM@CA.INTER.NET>

Dear Prasad

I sympathize with your confusion!! :-) I heard the phrase from a friend in
the Food Trade, and in this context it means "If your food is "passably
good", it is difficult to desire to improve it. "

Conventional wisdom says that we should strive for perfection. I think that
this is totally wrong, for the simple reason that to attain perfection, one
must exactly define all parameters that are relevant to the task or project.

Lanny has asked what I feel is a profoundly important question: "What are we
supposed to cook?" Why wasn't this question asked before?

Expressed in different terms: "These stoves we are building.... what are we
supposed to do with them anyway?" It is very much like the dog chasing the
car... what does he do when he catches it?

There is another phrase "Good enough is good enough." This flies in the face
of perfection, but I feel it is a far better "real world standard" for stove
design.

Actually, to make the point a bit a bit more clearly " A perfect stove is a
stove that perfectly accomplishes the desired task." Thus, a 3 stone fire
can be as perfect a stove as a 5 can stove, a Jotul, a Rocket, a Henson,
etc. At the same time, all these stove systems can be perfect, or total
failures. It all depends on how well they do what you want them to do. For
example, if the criteria for a perfect stove is that wherever I go in a rock
filled forest, I can find the means to make a stove and somewhat control the
fire, then the 3 stone fire is perfect. As soon as I introduce the criteria
of being able to cook a meal for 10 with less than 100 grams of fuel per
meal, the three stone fire is a dismal failure.

Now, at the great risk of appearing trivial, I ask the question:
"What is a good stove?"

Or perhaps I should be asking the question: "What is a stove supposed to
do?"

Aside from technical considerations, there is an economic layer also. If I
built a "perfect" stove, and one of the "terms of perfection" was that it
cost less than $20.00, then if my costs escalated to $20.01, it ceases to be
a perfect stove. There is, by definition, no tolerance for imperfection in
perfection. We must be very careful what we call for in a stove.
Additionally, we must have a "weighting", tolerance, or "common sense"
input, so that somehow, we can accept stoves "that do a really good job in
areas #1 to #9, but are a bit weak in area #10"

Best Wishes to all,

Kevin

----- Original Message -----
From: "Prasad, K." <K.Prasad@TUE.NL>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, January 13, 2004 7:57 AM
Subject: Re: [STOVES] Chimneys

> Dear Tom
>
> Should it not be "THE BEST IS THE ENEMY OF THE GOOD"
>
> I always thought engineering was about compromises (mathematically
speaking
> "optimization")and the best quite often ignores the price one pays for
> achieving it.
>
> Yours
> Prasad
>
> -----Original Message-----
> From: TBReed [mailto:tombreed@COMCAST.NET]
> Sent: Sunday, January 04, 2004 3:34 PM
> To: STOVES@LISTSERV.REPP.ORG
> Subject: Re: [STOVES] Chimneys
>
>
> Dear Das and All:
>
> I second all of Das's comments, but would like to add a few more on
> chimneys.
>
> The chimney is a good solution to combustion, but often
>
> "THE GOOD IS THE ENEMY OF THE BEST".
>
> The need to discard the combustion gases at a high enough temperature to
> maintain good draft (say 400 C? - comment?) Means that you are limiting
> heat recovery to
>
> (Tc-Td)/Tc
>
> (where Tc is the combustion temperature, Td is the draft temperature)
>
> This is like a Carnot law for Chimneys: It sets the upper bound of
> efficiency. If the fuel is burned near stoichimetric, Tc~1600 C, so a
draft
> temperature of 400 C would limit top efficiency to 75% (neglecting
high/low
> heating value concerns). However, it is difficult to burn coal or wood at
> that temperature, so this is an upper bound for efficiency.
>
> Today it is relatively easy and inexpensive to put an oxygen (lambda)
sensor
> on a stack and monitor the stoichiometry which then controls combustion
> temperature and efficiency.
>
> ~~~~~~~
> This efficiency loss is a high penalty for using a thermal draft. You can
> avoid it for biomass fuels by using a forced draft system and more
precisely
> controlling the combustin conditions.
>
> When burning coal, it is inadvisable to condense any water in the stck
> because it will contain sulfuric acid and eat up your pipes. However the
> sulfur concentration in most biomass is such that you can condense the
water
> and take advantage of the Higher heating value of the biomass. This means
> that in the US where we typically rate fuels on their Higher heating value
> you can approach 100% of the HHV efficiency, while in Europe where they
> usually use the LHV (no condensation) they are now achieving 110%
efficiency
> in many condensing biomass fuel installations!
>
> ~~~~~~~
> So we will all continue to use chimneys as as a practical solution to
draft,
> but keeping in mind that there is much better technology available when
the
> price is right.
>
> Onward,
>
>
> TOM REED
>
>
> ----- Original Message -----
> From: "Das" <das@EAGLE-ACCESS.NET>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Friday, January 02, 2004 2:29 PM
> Subject: Re: [STOVES] Chimneys
>
>
> > A recent Stovers posting made the most sound argument for flue pipe.
> > It gets the smoke and fumes of failure modes out of your living space.
> > As you have seen, I have put a flue on everything that I have here.
> >
> > An aditional goal of improved combustion is to increase the fraction of
> the
> > operating time with secondary combustion lightoff. Ideally we aim to
> > eliminate all release of uncombusted gases. Small grain fuels sugh as
> > chips offer much more steady gas quality and combustion quality.
> >
> > Larger fuel such as Cord wood goes through drastic cycles with fresh
fuel
> > extinguishing secondary burn, then excessive heat output, then char
burn,
> > then repeat the cycle.
> >
> > You are doing good work. It is an hoonor to work with you.
> >
> > A. Das
> > Original Sources/Biomass Energy Foundation
> > Box 7137, Boulder, CO 80306
> > das@eagle-access.net
> >
> > ----------
> > > From: Dean Still <dstill@EPUD.NET>
> > > To: STOVES@LISTSERV.REPP.ORG
> > > Subject: Re: [STOVES] Chimneys
> > > Date: Tuesday, December 16, 2003 12:37 AM
> > >
> > > Dear Alex,
> > >
> > > Our intention at Aprovecho is always to share all information and we
> hope
> > > that beginning this winter we can generate some accurate numbers for
> > various
> > > stoves. We received the $8,000 Enerac 3000E today! Should give us good
> > > readings of CO, CO2, O2, hydrocarbons...Thanks to the Murdock
> > Foundation...
> > >
> > > I look at chimneys in a very positive light because the cost is low
and
> > the
> > > cure to indoor air pollution, for all practical purposes, complete.
Here
> > in
> > > Oregon, we heat with wood, many folks use wood stoves as their only
> > heating
> > > source. Chimneys here need to be cleaned often, more often if the
stove
> > > burns badly as most do, some monthly. It is important to make the
> chimney
> > > easy to clean. The metal chimney in my house is twenty years old. The
55
> > > gallon barrel stove that heats our lab is more than twenty years old.
> > > Chimneys are the answer to IAP; the only question is how to fund their
> > > installation.
> > >
> > > The best combustion chamber can be easily defeated by operator error.
> > > Although fans and 1,000F preheated primary air are much harder to
defeat
> > > than stoves relying on natural draft. I love blast furnace heating
> stoves
> > > coupled to big heat exchangers! But simple cooking stoves without fans
> > are
> > > usually stuffed full of too much fuel, green as an apple. A chimney
> > guards
> > > the operator from their actions. Just have to clean it once in a
while.
> > Buy
> > > good stuff...
> > >
> > > Larry wants us to make light weight chimneys out of ceramic. Ken Goyer
> > > extruded a beauty a while back...
> > >
> > > All Best,
> > >
> > > Dean

From tmiles at TRMILES.COM Tue Jan 13 12:02:31 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:49 2004
Subject: compact biogas plant
Message-ID: <TUE.13.JAN.2004.120231.0500.TMILES@TRMILES.COM>

Dr. Karve

Here's an observation from Mathias Effenberger on the
Digestion@listserv.repp.org list regarding the compact biogas plant.

Dear Tom:

I wanted to reply shortly to your article, because I find the simple
digester design you described very intriguing. Large-scale biogas
technology here in Germany is becoming increasingly elaborate but also
expensive.

Combining different feedstocks appears important to me as I expect
progressional subtle decreases of biogas production due to depletion of
essential micronutrients if only a single substrate is used ("unbalanced
diet").

Greetings from Germany,

Mathias Effenberger, MSc
Bavarian State Research Center for Agriculture
Institute for Agricultural Engineering, Farm Buildings and Environmental
Technology
mathias.effenberger@lfl.bayern.de

From lanny at ROMAN.NET Tue Jan 13 18:40:32 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:49 2004
Subject: Cook Book
Message-ID: <TUE.13.JAN.2004.184032.0500.LANNY@ROMAN.NET>

Dear Prasad,
Great! I would like to be the first to purchase 2 copies of the cook book,
autographed if possible.
I did not want to ask for too much at once but since you also mentioned
chimneys I also need a book about the arcutecture of homes (construction
methods, materials used, and dimensions) as it relates to chimneys. I am
confident that cheep simple and functional chimney systems can be designed,
as well as the equipment to fabricate them. But I need information about how
homes are built in developing areas.
And like you said a list of the materials available to build stoves and
chimneys would be very! helpful as we morph our efficient but too expensive
stoves in to practical designs for developing areas.
I thank you in advance for your work.
Lanny Henson

----- Original Message -----
From: Prasad, K. <K.Prasad@tue.nl>
To: 'Lanny Henson' <lanny@ROMAN.NET>
Cc: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, January 13, 2004 6:31 AM
Subject: RE: [STOVES] 2004 Wish List

> Dear Lanny and other stovers
>
> A "cookbook of foods eaten in developing areas" is an excellent idea. I'm
> sure my former colleagues Pete Verhaart and Piet Visser and myself could
> contribute to such a book.
> Needless to say, similar effort on refractories, materials of
construction,
> and chimneys would also be very useful. Pete Verhaart and Piet visser are
> genuine Mechanical nengineers unlike me, the phoney one, could contribute
to
> this effort.
>
> Sorry Pete and Piet dragging your names like this.
>
> Yours
> Prasad
>
> -----Original Message-----
> From: Lanny Henson [mailto:lanny@ROMAN.NET]
> Sent: Wednesday, January 07, 2004 11:53 AM
> To: STOVES@LISTSERV.REPP.ORG
> Subject: Re: [STOVES] 2004 Wish List
>
>
> Tom,
> You are under appreciated. Thanks for doing an excellent job with the
> website.
> About #4, content by subject areas.
> A section about the foods cooked, recipes and cooking methods would be
> handy if anyone needed a research project.
> How about "a cook book of foods eaten in developing areas"?
> If we are building stoves we need to know about the foods to be cooked.
> Lanny Henson
>
> >4. Improved presentation of content in subject ares. For example, someone
> >needs to organize the data on refractory and materials of construction,
> >chimneys, etc.
>
>
> ----- Original Message -----
> From: Tom Miles <tmiles@TRMILES.COM>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Sunday, January 04, 2004 3:38 PM
> Subject: [STOVES] 2004 Wish List
>
>
> Stovers,
>
> It's time to make up a wish list for what you would like to see change on
> the Stoves list and website for 2004. Bear in mind that there is no budget
> for anything new but a volunteer group has been working to improve the
> listserv at REPP and so far REPP has been willing to support increased use
> of space on the website.
>
> Ideas for the list:
> http://listserv.repp.org/archives/stoves.html
>
> 1. Current stoves archives (since 2002) should be searchable on the web.
> This is in progress by the vounteer group. Archives prior to 2003 are
> searchable via Google and other search engines.
>
> 2. Improved listserver. This is also being worked on by the volunteer
group.
>
> Ideas for the Web site:
> http://www.repp.org/discussiongroups/resources/stoves/
>
> 1. Easier navigation.
> 2. References or bibliography section.
> 3. Site for electronic pre-prints, where list member can post images,
files
> or papers for review by others.
> 4. Improved presentation of content in subject ares. For example, someone
> needs to organize the data on refractory and materials of construction,
> chimneys, etc.
>
> What are your ideas? What would make it easier to find the information you
> need or present your ideas? Or are we doing just fine?
>
> Thanks for your help.
>
> Tom Miles
> tmiles@trmiles.com
>
>
>
> ----- Original Message -----
> From: Tom Miles <tmiles@TRMILES.COM>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Sunday, January 04, 2004 3:38 PM
> Subject: [STOVES] 2004 Wish List
>
>
> Stovers,
>
> It's time to make up a wish list for what you would like to see change on
> the Stoves list and website for 2004. Bear in mind that there is no budget
> for anything new but a volunteer group has been working to improve the
> listserv at REPP and so far REPP has been willing to support increased use
> of space on the website.
>
> Ideas for the list:
> http://listserv.repp.org/archives/stoves.html
>
> 1. Current stoves archives (since 2002) should be searchable on the web.
> This is in progress by the vounteer group. Archives prior to 2003 are
> searchable via Google and other search engines.
>
> 2. Improved listserver. This is also being worked on by the volunteer
group.
>
> Ideas for the Web site:
> http://www.repp.org/discussiongroups/resources/stoves/
>
> 1. Easier navigation.
> 2. References or bibliography section.
> 3. Site for electronic pre-prints, where list member can post images,
files
> or papers for review by others.
> 4. Improved presentation of content in subject ares. For example, someone
> needs to organize the data on refractory and materials of construction,
> chimneys, etc.
>
> What are your ideas? What would make it easier to find the information you
> need or present your ideas? Or are we doing just fine?
>
> Thanks for your help.
>
> Tom Miles
> tmiles@trmiles.com
>
>
>
>

From kmbryden at IASTATE.EDU Wed Jan 14 15:34:15 2004
From: kmbryden at IASTATE.EDU (Mark Bryden)
Date: Tue Aug 10 18:30:49 2004
Subject: pre registration form
Message-ID: <WED.14.JAN.2004.143415.0600.KMBRYDEN@IASTATE.EDU>

All,

Attached is the pre registration form for the ETHOS 2004 conference the
Partnership for Clean Indoor Air Stove Design and Performance Guidelines
Workshop.

Due to the number of people we anticipate will be attending it is important
that you preregister to ensure that sufficient space for all participants.

Please email the form below to
aholland@iastate.edu

Alternately this form can be printed and faxed to
Amy Holland at
1-515-294-5530

Thanks

Mark

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

ETHOS 2004 Pre-Registration Form

Engineers in Technical and Humanitarian Opportunities of Service
January 31-February 1, 2004
Seattle, Washington

First Name ____________________________________

Last Name ____________________________________

Name (first and last) to be used on your badge

______________________________________________

Title __________________________________________

Company ______________________________________

Address _______________________________________

City ____________________ State _____ Zip _________

Country _______________________________________

Phone _________________________________________

Fax ___________________________________________

Email __________________________________________

Events you will attend:

__ Ethos meeting (Jan. 31 - Feb. 1)

__ Stove Design and Performance Guidelines Workshop (Feb. 2 - Feb. 3)

Will you be staying at the hotel? __ Yes __ No

Would you like assistance in making reservations with the shuttle express
from the airport to the hotel __ Yes __ No. If yes, what time and day
are you arriving? __ Yes __ No

If you are staying at the hotel, do you have transportation to the
meeting? __ Yes __ No

If yes, do you have room in your car for others? __ Yes ( __ # of
spaces) __ No

What aspects of the event are of most interest to you?

From jmdavies at TELKOMSA.NET Thu Jan 15 09:43:21 2004
From: jmdavies at TELKOMSA.NET (John Davies)
Date: Tue Aug 10 18:30:49 2004
Subject: Quality stoves
Message-ID: <THU.15.JAN.2004.164321.0200.JMDAVIES@TELKOMSA.NET>

Greetings all,

Some thoughts below on these issues.

----- Original Message -----
From: "Kevin Chisholm" <kchisholm@ca.inter.net>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, January 13, 2004 3:59 PM
Subject: Re: [STOVES] Chimneys

"SNIPPED"
> Conventional wisdom says that we should strive for perfection. I think
that
> this is totally wrong, for the simple reason that to attain perfection,
one
> must exactly define all parameters that are relevant to the task or
project.

Perfection sounds like an "OVERKILL" but the parameters are important.

> Expressed in different terms: "These stoves we are building.... what are
we
> supposed to do with them anyway?" It is very much like the dog chasing the
> car... what does he do when he catches it?

Are we building stoves just to have good combustion ? Or are we building
them to fulfil a specific requirement? The latter automatically answers the
question.

> There is another phrase "Good enough is good enough." This flies in the
face
> of perfection, but I feel it is a far better "real world standard" for
stove
> design.

Good enough, sounds like an inferior product, something that we don't want !

> Actually, to make the point a bit a bit more clearly " A perfect stove is
a
> stove that perfectly accomplishes the desired task." Thus, a 3 stone fire
> can be as perfect a stove as a 5 can stove, a Jotul, a Rocket, a Henson,
> etc. At the same time, all these stove systems can be perfect, or total
> failures. It all depends on how well they do what you want them to do. For
> example, if the criteria for a perfect stove is that wherever I go in a
rock
> filled forest, I can find the means to make a stove and somewhat control
the
> fire, then the 3 stone fire is perfect. As soon as I introduce the
criteria
> of being able to cook a meal for 10 with less than 100 grams of fuel per
> meal, the three stone fire is a dismal failure.

> Or perhaps I should be asking the question: "What is a stove supposed to
> do?"

Important, Meet the requirements.

> Now, at the great risk of appearing trivial, I ask the question:
> "What is a good stove?

OK for what it is worth here is my criteria.

1 A good stove is a "QUALITY" stove

2 A "QUALITY PRODUCT , is neither perfect, or Good enough, it might even be
downright terrible. But It must meet all the predefined requirements for
which it is designed, which may be many or few.

3 Some Typical requirements listed below.

Combustion requirement.

Pot efficiency.

Amount of heat radiated to surroundings. ( may be required or not, and
maybe at specific times )

Rate of heat generation.

Removal of combustion gasses from immediate area.

Lifetime of stove.

Replaceable components available.

Cost of stove.

Size of stove

Height of stove

User friendly

Fuel availability and cost.

Adaptability to other heat uses, i.e. water heaters, ovens etc.

So you make up your own list of requirements. If the stove meets all the
requirements, which should match the intended users requirements, it is a
QUALITY STOVE. and the user will be sure to agree, which will create a
demand for the product.

Wishing you all a prosperous 2004.
John Davies.

From kchisholm at CA.INTER.NET Fri Jan 16 06:54:12 2004
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:49 2004
Subject: Quality stoves
Message-ID: <FRI.16.JAN.2004.075412.0400.KCHISHOLM@CA.INTER.NET>

Dear John
Sent: Thursday, January 15, 2004 10:43 AM
Subject: [STOVES] Quality stoves

> Greetings all,
>
> Some thoughts below on these issues.
>
> ----- Original Message -----
> From: "Kevin Chisholm" <kchisholm@ca.inter.net>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Tuesday, January 13, 2004 3:59 PM
> Subject: Re: [STOVES] Chimneys
>
>
>
> "SNIPPED"
> > Conventional wisdom says that we should strive for perfection. I think
> that
> > this is totally wrong, for the simple reason that to attain perfection,
> one
> > must exactly define all parameters that are relevant to the task or
> project.
>
> Perfection sounds like an "OVERKILL" but the parameters are important.
>
If we define "Perfection" as "implementation of the attainable", then
clearly, perfection is not necessary. I would suggest that we must do is
define all relevant parameters, and then build the stoves to meet the
specified level of each parameter.

> > Expressed in different terms: "These stoves we are building.... what are
> we
> > supposed to do with them anyway?" It is very much like the dog chasing
the
> > car... what does he do when he catches it?
>
> Are we building stoves just to have good combustion ? Or are we building
> them to fulfil a specific requirement? The latter automatically answers
the
> question.
>
Exactly!! Lanny Hansen seems to be the first to focus on the question of "If
stoves are to be used for cooking, just what are we supposed to be cooking?"
Thats pretty fundamental, I would suggest.

There was a major concern about Indoor Air Pollution, and I suggested that
smoke stacks would vent polluting fume outside. I thought that was pretty
fundamental also.

> > There is another phrase "Good enough is good enough." This flies in the
> face
> > of perfection, but I feel it is a far better "real world standard" for
> stove
> > design.
>
> Good enough, sounds like an inferior product, something that we don't want
!
>
If the product is inferior, then it is not good enough!! :-) The trick is to
do the least and still meet the "requirements" The key question is: "What
are the requirements for a good stove?" We can ask the same basic question
in two different ways, we get two radically different approaches to the
problem. For example:
1: What standards must I meet if I want to design a good stove?
2: How should I desn a stove to meet the market requirements?

One can see the very different approaches that will be taken, depending on
the question that one is given. However, if I design a "good" stove that
does not meet the market requirements, it will not get very far.

> > Actually, to make the point a bit a bit more clearly " A perfect stove
is
> a
> > stove that perfectly accomplishes the desired task." Thus, a 3 stone
fire
> > can be as perfect a stove as a 5 can stove, a Jotul, a Rocket, a Henson,
> > etc. At the same time, all these stove systems can be perfect, or total
> > failures. It all depends on how well they do what you want them to do.
For
> > example, if the criteria for a perfect stove is that wherever I go in a
> rock
> > filled forest, I can find the means to make a stove and somewhat control
> the
> > fire, then the 3 stone fire is perfect. As soon as I introduce the
> criteria
> > of being able to cook a meal for 10 with less than 100 grams of fuel per
> > meal, the three stone fire is a dismal failure.
>
> > Or perhaps I should be asking the question: "What is a stove supposed to
> > do?"
>
>
> Important, Meet the requirements.
>
Exactly!! Meeting requirements does not require attainment of perfection.

> > Now, at the great risk of appearing trivial, I ask the question:
> > "What is a good stove?
>
> OK for what it is worth here is my criteria.
>
> 1 A good stove is a "QUALITY" stove
>
> 2 A "QUALITY PRODUCT , is neither perfect, or Good enough, it might even
be
> downright terrible. But It must meet all the predefined requirements for
> which it is designed, which may be many or few.
>
I would suggest that there are two very important but very different issues
here:
1: Stove Specification: This is a definition of the totality of what a stove
design must accomplish.
2: Quality: This is simply a measure of the consistency of manufacturing of
the specified product .

> 3 Some Typical requirements listed below.
>
> Combustion requirement.
>
> Pot efficiency.
>
> Amount of heat radiated to surroundings. ( may be required or not, and
> maybe at specific times )
>
> Rate of heat generation.
>
> Removal of combustion gasses from immediate area.
>
> Lifetime of stove.
>
> Replaceable components available.
>
> Cost of stove.
>
> Size of stove
>
> Height of stove
>
> User friendly
>
> Fuel availability and cost.
>
> Adaptability to other heat uses, i.e. water heaters, ovens etc.
>
These are indeed all very important parameters for designing a stove.
However, one cas easily see that one must narrow the focus and design a
stove for a specific market requirement. For example, if I want to buy a
"Parlour Stove", I don't care about pot efficiency, cooking capability, or
water heating capability; all I might want is something that looks nice, is
efficient so that I don't have to lug too much wood, vents outside, and has
surface temperatures that won't burn my Grandchildren.

> So you make up your own list of requirements. If the stove meets all the
> requirements, which should match the intended users requirements, it is a
> QUALITY STOVE. and the user will be sure to agree, which will create a
> demand for the product.

The key thing is to find out what the End User wants and needs, and then
design the stove to meet these needs. Quality comes from building it on a
consistent basis.

The wrong way is to come up with a clever design which does an excellent job
of doing something that the User does not want done. :-)
>
Best wishes to All

Kevin Chisholm

From tombreed at COMCAST.NET Fri Jan 16 09:03:47 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:49 2004
Subject: Quality stoves
Message-ID: <FRI.16.JAN.2004.070347.0700.TOMBREED@COMCAST.NET>

Dear Kev, Lanny and All;

"THE GOOD IS THE ENEMY OF THE BEST"

should also be inverted to

"THE BEST IS THE ENEMY OF THE GOOD ENOUGH".

It's all a manner of timing and requirements.
Three stone stoves were "good enough" for humanity for 100,000 years and are
still "good enough" for 1/3 of families today.

However, our requirements in terms of cooking, health and energy efficiency
continually improve and if the 1/2 of humanity wants to improve these they
will have to make the extra effor that has characterized the "developed"
world, but in the context of a shrinking fossil fuel base.

So, many of us are trying to make improved biomass stoves based on our
improved understanding of the pyrolysis, gasification and combustion
processes that make biomass so much more complicated than the electricity,
propane, gasoline and kerosene available in the developed countries.

It will take a long time to sort out the Best from the Good Enough, and it
is fortunate that we have had this discussion on the balance between the
two.

----- Original Message -----
From: "Kevin Chisholm" <kchisholm@ca.inter.net>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, January 16, 2004 4:54 AM
Subject: Re: [STOVES] Quality stoves

> Dear John
> Sent: Thursday, January 15, 2004 10:43 AM
> Subject: [STOVES] Quality stoves
>
>
> > Greetings all,
> >
> > Some thoughts below on these issues.
> >
> > ----- Original Message -----
> > From: "Kevin Chisholm" <kchisholm@ca.inter.net>
> > To: <STOVES@LISTSERV.REPP.ORG>
> > Sent: Tuesday, January 13, 2004 3:59 PM
> > Subject: Re: [STOVES] Chimneys
> >
> >
> >
> > "SNIPPED"
> > > Conventional wisdom says that we should strive for perfection. I think
> > that
> > > this is totally wrong, for the simple reason that to attain
perfection,
> > one
> > > must exactly define all parameters that are relevant to the task or
> > project.
> >
> > Perfection sounds like an "OVERKILL" but the parameters are important.
> >
> If we define "Perfection" as "implementation of the attainable", then
> clearly, perfection is not necessary. I would suggest that we must do is
> define all relevant parameters, and then build the stoves to meet the
> specified level of each parameter.
>
> > > Expressed in different terms: "These stoves we are building.... what
are
> > we
> > > supposed to do with them anyway?" It is very much like the dog chasing
> the
> > > car... what does he do when he catches it?
> >
> > Are we building stoves just to have good combustion ? Or are we
building
> > them to fulfil a specific requirement? The latter automatically answers
> the
> > question.
> >
> Exactly!! Lanny Hansen seems to be the first to focus on the question of
"If
> stoves are to be used for cooking, just what are we supposed to be
cooking?"
> Thats pretty fundamental, I would suggest.
>
> There was a major concern about Indoor Air Pollution, and I suggested that
> smoke stacks would vent polluting fume outside. I thought that was pretty
> fundamental also.
>
> > > There is another phrase "Good enough is good enough." This flies in
the
> > face
> > > of perfection, but I feel it is a far better "real world standard" for
> > stove
> > > design.
> >
> > Good enough, sounds like an inferior product, something that we don't
want
> !
> >
> If the product is inferior, then it is not good enough!! :-) The trick is
to
> do the least and still meet the "requirements" The key question is: "What
> are the requirements for a good stove?" We can ask the same basic question
> in two different ways, we get two radically different approaches to the
> problem. For example:
> 1: What standards must I meet if I want to design a good stove?
> 2: How should I desn a stove to meet the market requirements?
>
> One can see the very different approaches that will be taken, depending on
> the question that one is given. However, if I design a "good" stove that
> does not meet the market requirements, it will not get very far.
>
> > > Actually, to make the point a bit a bit more clearly " A perfect stove
> is
> > a
> > > stove that perfectly accomplishes the desired task." Thus, a 3 stone
> fire
> > > can be as perfect a stove as a 5 can stove, a Jotul, a Rocket, a
Henson,
> > > etc. At the same time, all these stove systems can be perfect, or
total
> > > failures. It all depends on how well they do what you want them to do.
> For
> > > example, if the criteria for a perfect stove is that wherever I go in
a
> > rock
> > > filled forest, I can find the means to make a stove and somewhat
control
> > the
> > > fire, then the 3 stone fire is perfect. As soon as I introduce the
> > criteria
> > > of being able to cook a meal for 10 with less than 100 grams of fuel
per
> > > meal, the three stone fire is a dismal failure.
> >
> > > Or perhaps I should be asking the question: "What is a stove supposed
to
> > > do?"
> >
> >
> > Important, Meet the requirements.
> >
> Exactly!! Meeting requirements does not require attainment of perfection.
>
> > > Now, at the great risk of appearing trivial, I ask the question:
> > > "What is a good stove?
> >
> > OK for what it is worth here is my criteria.
> >
> > 1 A good stove is a "QUALITY" stove
> >
> > 2 A "QUALITY PRODUCT , is neither perfect, or Good enough, it might
even
> be
> > downright terrible. But It must meet all the predefined requirements for
> > which it is designed, which may be many or few.
> >
> I would suggest that there are two very important but very different
issues
> here:
> 1: Stove Specification: This is a definition of the totality of what a
stove
> design must accomplish.
> 2: Quality: This is simply a measure of the consistency of manufacturing
of
> the specified product .
>
> > 3 Some Typical requirements listed below.
> >
> > Combustion requirement.
> >
> > Pot efficiency.
> >
> > Amount of heat radiated to surroundings. ( may be required or not, and
> > maybe at specific times )
> >
> > Rate of heat generation.
> >
> > Removal of combustion gasses from immediate area.
> >
> > Lifetime of stove.
> >
> > Replaceable components available.
> >
> > Cost of stove.
> >
> > Size of stove
> >
> > Height of stove
> >
> > User friendly
> >
> > Fuel availability and cost.
> >
> > Adaptability to other heat uses, i.e. water heaters, ovens etc.
> >
> These are indeed all very important parameters for designing a stove.
> However, one cas easily see that one must narrow the focus and design a
> stove for a specific market requirement. For example, if I want to buy a
> "Parlour Stove", I don't care about pot efficiency, cooking capability, or
> water heating capability; all I might want is something that looks nice,
is
> efficient so that I don't have to lug too much wood, vents outside, and
has
> surface temperatures that won't burn my Grandchildren.
>
>
> > So you make up your own list of requirements. If the stove meets all the
> > requirements, which should match the intended users requirements, it is
a
> > QUALITY STOVE. and the user will be sure to agree, which will create a
> > demand for the product.
>
> The key thing is to find out what the End User wants and needs, and then
> design the stove to meet these needs. Quality comes from building it on a
> consistent basis.
>
> The wrong way is to come up with a clever design which does an excellent
job
> of doing something that the User does not want done. :-)
> >
> Best wishes to All
>
> Kevin Chisholm

From kchisholm at CA.INTER.NET Fri Jan 16 09:32:30 2004
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:49 2004
Subject: Quality stoves
Message-ID: <FRI.16.JAN.2004.103230.0400.KCHISHOLM@CA.INTER.NET>

Dear Tom
----- Original Message -----
From: "TBReed" <tombreed@comcast.net>
To: "Kevin Chisholm" <kchisholm@ca.inter.net>; <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, January 16, 2004 10:03 AM
Subject: Re: [STOVES] Quality stoves

> Dear Kev, Lanny and All;
>
> "THE GOOD IS THE ENEMY OF THE BEST"
>
> should also be inverted to
>
> "THE BEST IS THE ENEMY OF THE GOOD ENOUGH".
>
I would suggest: "THE ENEMY OF THE GOOD ENOUGH AND THE BEST IS THOSE OF US
WHO SIT AROUND IN THE FRONT OFFICE PONDERING ON THE WONDERFUL COMPLEXITY OF
FIRE, RATHER THAN SEEING WHAT THE REAL WORLD REALLY NEEDS, AND THEN BUILDING
A SET OF PRODUCTS THAT MEET THE VARIOUS NEEDS."

> It's all a manner of timing and requirements.
> Three stone stoves were "good enough" for humanity for 100,000 years and
are
> still "good enough" for 1/3 of families today.

If we have to triage, we can help them later.
>
> However, our requirements

Should not that be THEIR requirements?

> in terms of cooking, health and energy efficiency
> continually improve and if the 1/2 of humanity wants to improve these they
> will have to make the extra effor that has characterized the "developed"
> world, but in the context of a shrinking fossil fuel base.

Who are we to impose our standards on "they?" Would it not be better to let
"them" tell us what would make their lives better?
>
> So, many of us are trying to make improved biomass stoves based on our
> improved understanding of the pyrolysis, gasification and combustion
> processes that make biomass so much more complicated than the electricity,
> propane, gasoline and kerosene available in the developed countries.

Thats all wonderfully interesting stuff, but what does it have to do ith
what the User wants and needs? I would suggest that it is impossible to
build a "good" or a "best" stove when we don't even know what the User is
going to do with the stove!!
>
> It will take a long time to sort out the Best from the Good Enough, and it
> is fortunate that we have had this discussion on the balance between the
> two.

I think Lanny made an embarrasingly important Giant Step forward when he
asked "What do they want to do with the stoves?"

"If you give an Engineer a problem, any problem, no matter how difficult and
complicated, if he looks at it long enough and in teh right light, he can
always find a way to make it more complicated."

Lanny asked a simple and piercing question, that will bring us toward a
solution.

Kevin Chisholm
>
>

From jmdavies at TELKOMSA.NET Fri Jan 16 01:34:01 2004
From: jmdavies at TELKOMSA.NET (John Davies)
Date: Tue Aug 10 18:30:49 2004
Subject: Excess air
Message-ID: <FRI.16.JAN.2004.083401.0200.JMDAVIES@TELKOMSA.NET>

Greetings,

Some responses on the subject.

> On Mon, 29 Dec 2003 00:05:19 -0600, Tami Bond wrote:
>
> >
> >Okay, my comment was very loose, and written in *complete* absence of
> >formal learning. I just meant to say that excess air that came in the
inlet
> >and went through the combustion lowers the temperature;
>
> I am uneasy with this as it assumes that you can achieve
> stoichiometric combustion. Now I think this is near enough true with a
> good fuel like natural gas, I suspect it is not with a biomass fuel
> with realistic moisture content. I would like to hear of practical or
> measured experiments. To my mind the highest temperature is achieved
> at
however I wonder if there are cases were
> combustion cannot ensure enough oxygen molecules react with fuel
> molecules. In this case the loss of calorific value in pics may be
> sufficient to reduce temperatures, I cite the example of a glowing
> log, it never attains enough heat to ignite the pyrolysis gas until
> you blow on it and it bursts into flame.
>

An example that comes to mind is that of the Gasifier combustion system in a
steam locomotive of the railway type. Whether coal or biomass is being used
as a fuel, the same principles apply.

In the case of the Red Devil locomotive, the requirement was to achieve
maximum heat output from the bituminous coal fuel. The gasses leaving the
gasifier bed was a combination of Hydrogen, Carbon Monoxide and various
Hydrocarbon gasses and some steam, as well as small suspended coal particles
lifted from the bed due to the high velocity of the gas. at a temperature of
about 800 C. Cold secondary air was jetted into the gas flow horizontally
and vertically downward from many positions around and above the combustion
chamber.creating the maximum possible turbulent mixing of air and gas. To
some of the air flows a steam jet was added to ensure complete coverage over
the fuel bed and best possible turbulence. A brick arch (Ceramic heat
reflector )covered most of the combustion area. The result was that the
gasses burned with a bright white/yellow flame which filled the entire
combustion area.
The Ceramic reflector was white hot.

Now for the combustion facts.

25% excess air was used ( 125% of stoichiometric air )
flame temperatures in the region of 1200C were achieved.
Combustion efficiency was 85%
Combustion losses were reported to be in the form of unburned Carbon
monoxide 15%

Increasing the excess air would have resulted in better combustion
efficiency at the cost of a lower flue gas temperature and larger volume,
which was contra indicated in this particular application.

As somebody mentioned, it is a case of temperature, turbulence, and
retention time.
The Gas mixture and steam content will also have an effect, as different
combustible gasses have different flame speeds and reactance with oxygen at
different temperatures.

I come to the conclusion that the excess air required in any application in
order to achieve the desired result will depend on the combination of
physical factors dealt with above, and that it will be different for each
application.

PERFECT COMBUSTION
The closest to total combustion that can be reached with stoichiometric air
is achieved by surface combustion as discovered by Sir Humphrey Davey.in
1817 and applied to a steam boiler by Professor W A Bone and Mr C D McCourt
shortly after 1902.

A mixture of gas and air is passed through a porous medium at incandescent
temperature. the combustion takes place without flame producing the highest
possible temperature which maintains the incandescent temperature of the
medium. ( ref. Heat Engines D A Low, London 1920 ) ( has been revised and
reprinted many times )

I see great opportunities with this method for gasifier stoves. Adding a
catalyst to the medium would allow a very thin bed to be used, totally
eliminate soot formation and increase the efficiency of the stove as no
excess air would be needed.

Has anybody done experiments along these lines with stoves. ?

----- Original Message -----
From: "Kanchan Rai" <Kanchan@KU.EDU.NP>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, January 12, 2004 10:17 PM
Subject: Re: [STOVES] Excess air

> I have an idea in which everything in my calculation looks fine but only
> thing worried me is at one point secondary air have to flow downwwards. As
> we know hot air will tend to move upward. Now its upon the pressure
> difference inside secondary chamber and atmosphere and the hot air flowing
> downward, I am very much like to see which will win but here with me is
> very little equipements to work with. Do you ( all stovers) have any idea
> to measure the negative pressure inside hot combustion chamber (above
> 800C)?

Air flow is determined by pressure gradient, and the hot air will flow
downward provided that the negative pressure in the combustion zone is lower
than the negative pressure formed by the hot air. this applies to all flows
within the stove system. sufficient chimney height will achieve this. The
relative flows of secondary air to primary air are achieved by the relative
resistance to flow in each section. While this is usually achieved by
dampers, the internal flow resistance of the unit can also be used which
includes the flow resistance of the fuel bed.

Measuring the negative pressure at any point in the system can be achieved
by using a water manometer. As the pressures are only likely to be a few mm
of water gauge , the manometer will have to be tilted at an angle close to
horizontal in order to read fractions of a millimeter.

Keep them Burning,
John Davies.

From pverhaart at OPTUSNET.COM.AU Sun Jan 18 01:11:12 2004
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:49 2004
Subject: It ain't Rocket Science
In-Reply-To: <007f01c3dc3e$40958650$799a0a40@kevin>
Message-ID: <SUN.18.JAN.2004.161112.1000.PVERHAART@OPTUSNET.COM.AU>

"After all, it ain't rocket science"
For quite a while now I have been thinking about this remark, made on the
List some time ago.
I think the implication was "You don't need first class brains to solve the
problems of woodburning cookstoves, 2nd or 3rd class grey matter will do
quite well."
It also made me think about the other side of the question: "How would a
rocket scientist tackle the problem?"
Now I know.
A rocket scientist would look into the combustion properties of wood and
compare it to properties of the more researched fuels, oils, coal and gases
and come to the conclusion that what is needed is wood in a finely divided
form. In that case it can be metered properly and immediately respond to
the needs. Next he or she will realise that this will only work on a fairly
large scale.
Then (s)he thinks of the high temperatures reached in combustion and think
of an efficient way to utilize it. Sadi Carnot and James Watt come to mind
as well as Thomas A. Edison and Freiherr von Siemens.
To cut the story short, what the rocket scientist comes up with is an
integral energy system. Wood is pulverised and entrained by a current of
air and injected into the combustion chamber of a boiler. The steam is
superheated and led through a turbine which drives a generator. The
generator powers an electric grid and those needing cookstoves can use mass
produced electric stovetops and ovens. The efficiency well above 30 %
That is why what we do ain't Rocket Science.

Peter Verhaart

From Gavin at AA3GENERGI.FORCE9.CO.UK Sun Jan 18 04:41:48 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:49 2004
Subject: It ain't Rocket Science
In-Reply-To: <5.2.0.9.2.20040118155235.00b5f268@mail.optusnet.com.au>
Message-ID: <SUN.18.JAN.2004.094148.0000.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Quite so,
We should be able to achieve higher overall efficiencies,
Only use fuel when we need heat
And produce a controllable heat source for a fraction of the cost per user.

What would the rocket scientist do given the correct brief and conditions?
gavin
"After all, it ain't rocket science"
For quite a while now I have been thinking about this remark, made on the
List some time ago.
I think the implication was "You don't need first class brains to solve the
problems of woodburning cookstoves, 2nd or 3rd class grey matter will do
quite well."
It also made me think about the other side of the question: "How would a
rocket scientist tackle the problem?"
Now I know.
A rocket scientist would look into the combustion properties of wood and
compare it to properties of the more researched fuels, oils, coal and gases
and come to the conclusion that what is needed is wood in a finely divided
form. In that case it can be metered properly and immediately respond to
the needs. Next he or she will realise that this will only work on a fairly
large scale.
Then (s)he thinks of the high temperatures reached in combustion and think
of an efficient way to utilize it. Sadi Carnot and James Watt come to mind
as well as Thomas A. Edison and Freiherr von Siemens.
To cut the story short, what the rocket scientist comes up with is an
integral energy system. Wood is pulverised and entrained by a current of
air and injected into the combustion chamber of a boiler. The steam is
superheated and led through a turbine which drives a generator. The
generator powers an electric grid and those needing cookstoves can use mass
produced electric stovetops and ovens. The efficiency well above 30 %
That is why what we do ain't Rocket Science.

Peter Verhaart

From pverhaart at OPTUSNET.COM.AU Sun Jan 18 06:06:32 2004
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:49 2004
Subject: It ain't Rocket Science
In-Reply-To: <MABBJLGAAFJBOBCKKPMGEECLDEAA.Gavin@aa3genergi.force9.co.uk >
Message-ID: <SUN.18.JAN.2004.210632.1000.PVERHAART@OPTUSNET.COM.AU>

At 09:41 18/01/2004 +0000, you wrote:
>Quite so,
>We should be able to achieve higher overall efficiencies,
>Only use fuel when we need heat
>And produce a controllable heat source for a fraction of the cost per user.
>
>What would the rocket scientist do given the correct brief and conditions?
>gavin

I don't know, after all, I ain't a rocket scientist.

Peter Verhaart

From andrew.heggie at DTN.NTL.COM Sun Jan 18 17:03:55 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:49 2004
Subject: It ain't Rocket Science
In-Reply-To: <5.2.0.9.2.20040118155235.00b5f268@mail.optusnet.com.au>
Message-ID: <SUN.18.JAN.2004.220355.0000.>

On Sun, 18 Jan 2004 16:11:12 +1000, Peter Verhaart wrote:

>That is why what we do ain't Rocket Science.
>
>Peter Verhaart

And its because what we do doesn't attract rocket science budgets,
innit?

AJH

From andrew.heggie at DTN.NTL.COM Sun Jan 18 17:03:58 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:49 2004
Subject: Excess air
In-Reply-To: <43011.203.91.135.149.1073938664.squirrel@www.webmail.ku.edu.np>
Message-ID: <SUN.18.JAN.2004.220358.0000.>

On Tue, 13 Jan 2004 02:02:44 +0545, Kanchan Rai wrote:

>My idea is pretty rough and may sound silly too. But what I think,
>particularty for metal stove, pressure difference will make this possible.
>For this, CHIMNEY is very essential. When volatiles (from primary
>combustion) burns at the secondary combustion zone , the flue leaves
>through chimney and there will be pressure drop inside combustion chamber.

Firstly I would point out that in the past this list seemed to lean to
the feeling that chimneys were culturally not acceptable. Not being in
the field I cannot comment, Tom Reed has shown there can be a high
energy cost of using a chimney. In the past I have tried to see if non
electrical means of providing a powered draught might be feasible.
There are benefits in powered draught over a chimney, there are large
benefits in exhausting combustion products from a room.

>If we possible to design such a way that all the primary air is completely
>consumed at the primary combustion zone

This is normally guaranteed by a high firebed temperature (1100C) and
an adequate firebed depth (defined in the past by Tom Reed as >20
fuelbed particle diameters to gasify the char to CO, intuitively less
would be adequate to mop up the O2 to a mixture of CO and CO2).

> and there is no other way to
>balance the pressure difference (in secondary combustion zone) apart from
>secondary air, I guess it will work. My Idea is to use primary air only to
>control the burning rate and rest (complete combustion) by secondary air.

Yes this is normal method of power control.
>
>I have an idea in which everything in my calculation looks fine but only
>thing worried me is at one point secondary air have to flow downwwards. As
>we know hot air will tend to move upward. Now its upon the pressure
>difference inside secondary chamber and atmosphere and the hot air flowing
>downward, I am very much like to see which will win but here with me is
>very little equipements to work with.

As John Davies has pointed out you only need to look at the overall
difference between inlet and flue outlet, if there is a pressure
difference the air will flow. If you make the path too tortuous then
the drag may prevent enough flow. Chimneys are an interesting and
complex subject, Alex English posted some numbers on chimney draught
way back. In effect you are considering two columns of gases, one is
the atmospheric gas and the other is the gas in the chimney length. As
the gas in the chimney is hotter than the atmospheric it expands (by
1/273 per deg C) and occupies more space in the chimney. This change
in density means the buoyancy of the gas in the chimney causes the
pressure difference between inlet and outlet. The pressure difference
over a cross section of the airflow has dimensions of force, so it can
accelerate a mass of air. Set against this is the drag on the air,
which is related to its velocity^2. So the condition where the
pressure can sustain an air velocity is determined by the drag and the
velocity for any pressure difference. Worse than this is that the
velocity varies over a given cross section as the gas temperature
varies, so it takes more force to push a hot gas than a cold one. Even
mass flow varies through the system depending on rate of burning. It
would be interesting to work in a laboratory where the power in inlet
air flow could be compared with the power in the flue gas (power
having dimensions of pressure time volume flow and only related to
massflow indirectly depending on temperature and molecular weights of
the components).

> Do you ( all stovers) have any idea
>to measure the negative pressure inside hot combustion chamber (above
>800C)?

Again as John Davies said, as long as the manometer is kept away from
the hot gases by a length of thin metal pipe (to conduct heat away)
there is no problem, except the pressure differences are tiny and not
only will the scale need to be on a shallow inclined tube but also the
tube contents are usually a died organic liquid that does not have
some of the disadvantages of water with respect to meniscus and
capillary attraction.

AJH

From anilrajvanshi at VSNL.COM Mon Jan 19 01:20:30 2004
From: anilrajvanshi at VSNL.COM (Anil K Rajvanshi)
Date: Tue Aug 10 18:30:49 2004
Subject: Rocket Science
Message-ID: <MON.19.JAN.2004.012030.0500.ANILRAJVANSHI@VSNL.COM>

I agree with Peter Veinhart. We need very good scientific thinking in
stoves research. The simpler the system is the more sophisticated thought
is required to make it that way. The rocket science research in stoves
could be on the lines proposed in my recent paper.
http://pune.sancharnet.in/nariphaltan/housenergy.pdf

Cheers.

Anil K Rajvanshi

From wsb at LAVA.NET Tue Jan 20 17:58:29 2004
From: wsb at LAVA.NET (Warren Bollmeier)
Date: Tue Aug 10 18:30:49 2004
Subject: Rocket Science, Rocket Engineering and Cookstove Design
Message-ID: <TUE.20.JAN.2004.125829.1000.WSB@LAVA.NET>

Aloha,

Let me preface my comments on Rocket Science and Cookstove Design and also
date myself in the process:

? On the front-end of my career, which was served in the United States
Air Force, I worked on rocket motor designs and thus considered myself a
Rocket Engineer, which to some would appear to be the application of Rocket
Science (However, that was also 30 years ago),

? Since then, I have spent most of my time on renewable energy sources of
electricity, and

? As an avid listener on the Stover List, I am clearly not a stove
designer and certainly not a combustion expert.

Notwithstanding the above, I have this to say about ?It Ain?t Rocket Science?:

Overall: It is quite likely that the combustion processes in cookstoves is
more complex and gaining an understanding of the Science of Cookstoves is
more difficult than Rocket Science, so many of you are right ? ?It Ain?t
Rocket Science? ? it is more difficult, in my opinion.

In support of this argument:

Point #1: Designing Solid Rocket Motors vs. Cookstoves. Solid Rocket
Motors (not to be confused with Liquid Rocket Engines) are, in concept,
relatively simple devices integrating a case and a nozzle. The case, made
of exotic, light-weight materials, holds highly-energetic solid
propellants, which when ignited, create a stream of combustion gases that
reach supersonic velocity at the throat of the nozzle and then expand to
much higher velocities at the exit of the nozzle. While simple in concept,
the application is indeed complex. However, the Rocket Engineers are able
to model rocket motor design in sufficient detail to effect reliable
operation. So, Point #1: I don?t believe we have a comparable modeling
capability for cookstoves.

Note: Liquid Rocket engines are more complex than Solid Rocket Motors, and
have more flexibility. Specifically, the fuels, such as liquid hydrogen
and liquid oxygen, are uniform and controllable via metering
systems. Thus, the performance is more controllable than for Solid Rocket
Motor, which essentially build up to a peak amount of thrust for a
specified period of time and then taper off. Also, Liquid Rocket Engines
have the capability of starting up and shutting down several times, while
the ignition of the Solid Rocket Motor is a one-shot deal.

Point #2: The design parameters for cookstoves are perhaps more complex and
certainly more variable. For example, comparing a Solid Rocket Motor vs. a
Cookstove, a Solid Rocket Motor has:

(1) one capability ? one firing profile and it only has to do it one time
(not multiple capabilities for cookstoves to boil water vs. simmer rice or
beans, etc., and be able to do this day after day),

(2) one batch load of fuel (with rocket engines, the fuels such as liquid
hydrogen and oxygen are metered, and thus controllable) with the same
characteristics (as opposed to biomass fuels of multiple sizes, types of
fuels, varying amounts of moisture in the fuels, etc.), and

(3) a precise amount of oxygen embedded in the fuels (while the oxygen in
biomass fuels is more limited and designing primary and secondary airflow
into airflow out of cookstoves appears to be quite challenging).

Point #3: The design process is evolving in a non-Aerospace environment
(i.e., lacks sufficient funding). Perhaps someday, there will be a model
powerful enough to optimize cookstove design details (go get ?em
Mark). However, in the meantime, it occurs to me to attempt to discern
what might be transferred from Rocket (no pun intended for you Rocket Stove
guys out there) Engineering to the cookstove design process: Here are my
first thoughts, some of which can be confirmed from my listening to you
guys already:

(1) cookstoves design is application specific (in this case, what type of
food is being cooked an how), and that trade-offs are necessary if one
wants to boil water rapidly and also be able to simmer rice or beans,
etc. Assessment: I believe cookstove designers are already a ways down
this path;

(2) consistency (OK, quality control) is needed in cookstove fabrication
(or manufacturing) and fuel preparation. I believe Quality Control is
already being addressed in terms of utilizing templates or molds for
fabrication of certain stoves, combustion chamber inserts, etc., and also
in biomass briquetting (ala Richard Stanley) and better methods for
production of charcoal (ala A. D. Karve, Elk Karsted and others); and

(3) innovations in air flow and control. Certainly, this can be
accomplished, e.g., Tom Reed?s gasifying stove. But what about control for
the input and exhaust of Rocket and other stoves? Here is my impression
based on listening (so please correct me if I am wrong): Assume first that
the Stove Operator (or Attendant) monitors the addition of fuel (let?s say
wood) into the combustion chamber, once the cookstove is lit and cooking is
underway. The Stove might achieve a pretty constant internal temperature
and pressure, based on the design of the input and output flow
channels. While an internal or external chimney helps facilitate the air
flow in and out, I am wondering if we have given enough thought to the
design of input channel? Here is why I think this might be one area to
investigate further. It has been suggested that combustion will be
enhanced by mixing and that got me to thinking maybe if we increased the
turbulence in the input channel? Thus might be done by roughening the
surface of the input channel, much like is done to increase the turbulence
on the top of airplane wings to keep the flow attached.

Well, I have said my piece, and perhaps this will help fan some discussion
at the Seattle meetings. CU there!

Cheers,

Warren

From tombreed at COMCAST.NET Wed Jan 21 07:49:20 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:49 2004
Subject: It ain't Rocket Science
Message-ID: <WED.21.JAN.2004.054920.0700.TOMBREED@COMCAST.NET>

Dear Pete:

Good description of how we developed the WoodGas CookStove. See new
pictures at www.woodgasllc.com...

TOM REED

----- Original Message -----
From: "Peter Verhaart" <pverhaart@OPTUSNET.COM.AU>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, January 17, 2004 11:11 PM
Subject: [STOVES] It ain't Rocket Science

> "After all, it ain't rocket science"
> For quite a while now I have been thinking about this remark, made on the
> List some time ago.
> I think the implication was "You don't need first class brains to solve
the
> problems of woodburning cookstoves, 2nd or 3rd class grey matter will do
> quite well."
> It also made me think about the other side of the question: "How would a
> rocket scientist tackle the problem?"
> Now I know.
> A rocket scientist would look into the combustion properties of wood and
> compare it to properties of the more researched fuels, oils, coal and
gases
> and come to the conclusion that what is needed is wood in a finely divided
> form. In that case it can be metered properly and immediately respond to
> the needs. Next he or she will realise that this will only work on a
fairly
> large scale.
> Then (s)he thinks of the high temperatures reached in combustion and think
> of an efficient way to utilize it. Sadi Carnot and James Watt come to mind
> as well as Thomas A. Edison and Freiherr von Siemens.
> To cut the story short, what the rocket scientist comes up with is an
> integral energy system. Wood is pulverised and entrained by a current of
> air and injected into the combustion chamber of a boiler. The steam is
> superheated and led through a turbine which drives a generator. The
> generator powers an electric grid and those needing cookstoves can use
mass
> produced electric stovetops and ovens. The efficiency well above 30 %
> That is why what we do ain't Rocket Science.
>
> Peter Verhaart

From jmdavies at TELKOMSA.NET Wed Jan 21 15:25:48 2004
From: jmdavies at TELKOMSA.NET (John Davies)
Date: Tue Aug 10 18:30:49 2004
Subject: Chimneys
Message-ID: <WED.21.JAN.2004.222548.0200.JMDAVIES@TELKOMSA.NET>

Greetings,

A late contribution to the chimney discussion, and a point that I do not
think was considered.

No matter how well a stove burns it will produce some smoke at start up,
which deposites a sooty layer inside the chimney, together with this soot is
bound to be some cresote and tars.

Now I wish to debate whether this layer protects the metal chimney from acid
or just straight oxidation attack.

My thoughts tend to believe that this layer is of a protective nature, right
or wrong, your thoughts will be welcome.

John Davies.

From crispin at NEWDAWN.SZ Thu Jan 22 09:40:16 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:49 2004
Subject: Chimneys
Message-ID: <THU.22.JAN.2004.164016.0200.CRISPIN@NEWDAWN.SZ>

Dear John

I think that top lighting a wood stove carefully (well... not even all that
carefully) results in virtually no smoke at all, at least none that can be
seen.

I have a feeling that lighting a coal stove might be done 'cleanly' if
alcohol was used instead of paraffin. Have you tried that and was there a
noticeable difference?

WOuld it be possible to conclude that a _really_ clean chimney wouldn't last
as long as a dirty one if the combustion wasn't all that good (i.e.
'ordinary'?

Regards
Crispin

----- Original Message -----
From: "John Davies" <jmdavies@TELKOMSA.NET>
Subject: Re: [STOVES] Chimneys

Greetings,

A late contribution to the chimney discussion, and a point that I do not
think was considered.

No matter how well a stove burns it will produce some smoke at start up,
which deposites a sooty layer inside the chimney, together with this soot is
bound to be some cresote and tars.
[snip]

From jmdavies at TELKOMSA.NET Fri Jan 23 16:27:08 2004
From: jmdavies at TELKOMSA.NET (John Davies)
Date: Tue Aug 10 18:30:49 2004
Subject: Chimneys
Message-ID: <FRI.23.JAN.2004.232708.0200.JMDAVIES@TELKOMSA.NET>

----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, January 22, 2004 4:40 PM
Subject: Re: [STOVES] Chimneys

> Dear John

> I have a feeling that lighting a coal stove might be done 'cleanly' if
> alcohol was used instead of paraffin. Have you tried that and was there a
> noticeable difference?

As you have seen the stove in action, you will agree that the initial
combustion of the paraffin ( illiminating Kerosene ) is far from complete.
the same applies to a lesser extent, to the firewood used as a starter, with
the combustion running away at this point, and producing smoke for the first
minute or so. This extremely high combustion rate is necessary to heat the
top layer of coal to combustion temperature. We have here the problem of
burning wood and kerosene in a stove that is not designed for it.

Now taking the target user into consideration, paraffin is a familiar fuel
and does not form an explosive mixture in the stove. It is also freely
available and a cheaper fuel. I have not tried using alcohol for this very
reason, but am sure that it would reduce that initial smoke.

In terms of deviating from the current standard lighting method, I would be
more inclined to do some tests using paper instead of the paraffin, as this
is more likely to be tried out by the user.

> WOuld it be possible to conclude that a _really_ clean chimney wouldn't
last
> as long as a dirty one if the combustion wasn't all that good (i.e.
> 'ordinary'?

Would it not ? This is what I am trying to find out. Each lighting of my
stove starts ordinary and then goes onto good soot free combustion, no
chance of blocking the chimney but a very light soot coating at each start
up.

Keep them burning, Clean and hot.

John Davies.

From tmiles at TRMILES.COM Sat Jan 24 13:27:56 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:49 2004
Subject: Postdoctoral Researcher Position in Air Pollution and Health
Message-ID: <SAT.24.JAN.2004.102756.0800.TMILES@TRMILES.COM>

> *** Postdoctoral Researcher Position ***

> Air Pollution and Health in Developing Countries
> School of Public Health, University of California, Berkeley
>
> A two-year research position with possible extension is available at
> the School of Public Health, University of California Berkeley, to
> work on health and environmental aspects of indoor and outdoor air
> pollution in developing countries. Working with colleagues at UCB and
> in Guatemala, India, China, and elsewhere, the researcher will conduct
> analyses of exposure, health, and other field data being gathered in
> rural areas of developing countries. In addition, the researcher will
> assist in the design, funding, and implementation of new field studies
> and policy analyses. Information about some of the ongoing research in
> the group can be found at the website:
> http://ehs.sph.berkeley.edu/krsmith/
>
> Qualifications:
>
> Ph.D. or other equivalent degree in a relevant field but not to be
> more than 5 years past receipt of the degree. Strength in at least
> two of the following topics as demonstrated through training and/or
> research:
> * Statistical analysis of large datasets;
> * Exposure assessment for indoor air pollution;
> * Health impacts of air pollution;
> * Small-scale combustion technology;
> * Environmental epidemiology;
> * Air pollution monitoring technology.
>
> A speaking and reading knowledge of Spanish is highly desirable, but
> not required. Developing-country research experience is desirable.
> Required is the ability to undertake international travel and to live
> for short periods in simple conditions in rural areas.
>
> Specific tasks: Conduct analysis of epidemiologic, exposure, and
> laboratory data; develop ongoing quality control measures for field
> data collection; assist in developing systematic documentation of
> study procedures and documentation of databases; deploy and evaluate
> new pollution and exposure monitoring technologies. Play an active
> role in data analysis, report writing, development of manuscripts, and
> preparation of grant applications. Participate as a member of study
> management teams. Assist graduate students with data analysis.
>
> Salary range: commensurate with experience.
> Approximate start date: 4/1/04 or until filled
>
> Please send a complete resume, two examples of writing (no more than
> 30 pages total), and the names and contact information for 3
> references. Included should be a detailed cover letter explaining how
> you meet the requirements of the position and how the position fits
> into your career plans. (Please send all items for consideration)
>
> Send to: Kacy Hone
> Payroll/Personnel Coordinator
> Division of Environmental Health Sciences
> 140 Warren Hall #7360
> Berkeley, CA 94720-7360
> email: kacyhone@berkeley.edu

From jmdavies at TELKOMSA.NET Sun Jan 25 03:25:32 2004
From: jmdavies at TELKOMSA.NET (John Davies)
Date: Tue Aug 10 18:30:49 2004
Subject: Fw: Chimneys
Message-ID: <SUN.25.JAN.2004.102532.0200.JMDAVIES@TELKOMSA.NET>

> Hi Ron,
>
> Good to hear from you,
>
> I presume that you meant this message to go to stoves and not direct to
me.
> I post it to stoves as well.
>
> See below.
>
> ----- Original Message -----
> From: "Ron Larson" <ronallarson@qwest.net>
> To: "John Davies" <jmdavies@TELKOMSA.NET>
> Sent: Saturday, January 24, 2004 2:30 AM
> Subject: Re: Chimneys
>
>
> > John, Crispin, et al
> >
> > I'd be interesting in hearing of the results of starting your pile
of
> > coal with either charcoal or coke on the top layer (which is either
dumped
> > in hot or lit with paraffin, alcohol, etc). The theory being that the
> > charcoal is pretty much gas-free and smoky off-gasing from the coal that
> is
> > traveling upward through the charcoal or coke should be well combusted.
> >
> > Ron
>
> Lighting with hot coals.
> As the target user is usually starting a fire from scratch, this method
has
> not been tried. I should imagine that your assumption of no smoke will be
> correct. After all the post lighting condition is instantly achieved, with
> hot gasses above the hot coals ( including CO ) being burned by secondary
> air, with the hot coals being the ignition source.
>
> Lighting with paraffin soaked charcoal.
> I initially used this method, before realizing that the target user does
not
> use charcoal, being 2 1/2 times the price of firewood and about 5 times
the
> cost of coal ( per unit mass ), and marginally more expensive than
> electricity per unit of
> heat. ( South African Costs )
>
> Smoke was produced during the first minute but slightly less than with
wood
> and of a shorter time duration. This is attributed to the fact that the
> stove is not receiving enough secondary air to consume all the gasses.
> ( originating from paraffin and wood ) This was the lighting method that
> Crispin observed,
>
> Conclusion.
> One could add another secondary air system to handle the light up
condition
> and achieve perfection, but this will add to the stove cost and complexity
> of operating it. Where a simple control system is called for This is not
> considered necessary as the initial smoke is of a relatively small volume
> and of short time duration, compared to the total burn time of up to 8
> hours.
>
> Taken against the background of the brazier or "embaula" ( 20 Li tin
punched
> full of holes ) which produces heavy acrid smoke for about an hour or
> more,and used twice as much coal for the same heating applications, the
> little smoke produced is of little consequence, relatively speaking. I
> estimate that the smoke produced is less than 1% of that of the brazier,
> and CO production being a very small fraction. One item that cannot be
> addressed by any stove is the Sulfur fumes, but the stove will reduce this
> by about half due to the lower coal consumption.
>
> The bottom line is that such a stove will clean up the terrible pollution
> problem experienced in the townships during the winter, when a low
inversion
> layer traps all the pollution being produced.
>
> The coal used is of a high bitumen content.
> The fumes produced from partially combusted bitumen in the coal are
> Carcinogenic as well as causing physical respiratory problems.
>
> Keep them burning,
> Bright and clean.
>
> John Davies.
>
>
>
>
>
>
>
>
>
>
>
>

From Kanchan at KU.EDU.NP Fri Jan 23 15:24:30 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:30:49 2004
Subject: Insulative ceramics
Message-ID: <SAT.24.JAN.2004.020930.0545.KANCHAN@KU.EDU.NP>

Dear Dean and Damon Ogle,
I have got an opportunity to read a recent edition of Boiling point
(Forest, fuel and food) where I found a paper on "Insulattive ceramics
for improved cooking stoves". That is very good one and useful for me as
I am doing similar kind of work in Nepal.

It gave ideas of insulative filler material like Perlite, Vermiculite,
pumice but unfortunately these are not available here. I tried with
clay(mud) and charcoal, mud porous (using wax) and only mud. I did some
tests with my limited equipements and some comparitive data. I didn't
used these things in stoves but on a electric heater to see its
insulative effect.

If you like I can share with you, I have a short Powerpoint file on
this. If you like I can send it to you. I will greatly appreciate your
commments and advice on it. I feel I can learn much from you on these
things.

Thanks for working on stove and sharing all your experiences, it is very
much beneficial for the countries like Nepal.

I look forward for yours' response

Regards,
Kanchan

From rdboyt at YAHOO.COM Sun Jan 25 15:39:13 2004
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:49 2004
Subject: Ten Can Stove Improvements
Message-ID: <SUN.25.JAN.2004.123913.0800.RDBOYT@YAHOO.COM>

Greetings Stovers,

I’m having some success improving the old tin can
stove (Feb 16, 1998), particularly the combustion
chamber. I’m aiming at the same goals of no cost,
small (18 cm by 16 cm dia., [7” by 6” dia]), light
weight (680 grams [1.5 pound]), portable, made from
found materials (tin cans, wood ash, native clay),
buildable by semi-skilled craftsmen using hand tools,
fueled by a small (40 gram [1.5 oz]) batch load of
naturally shed twigs.

The stove is top lit with controlable pre-heated
primary and secondary air that picks up heat as it
cools the stove body by traveling down, up, down, then
finally up through the fuel. Add a glass window to
monitor flame and/or provide light. Natural draft is
augmented by a lightweight adustable-height shrouded
exterior tin can chimney (July, 2003). Flue gas exit
temperature of 95 degrees C (200 degrees F) is great
for warming hands on a cold day.

The tin can combustion chamber is lined with a wood
ash/ clay mix which is resistant to high temperature
thermal shock. The cooking pot is a 1/2 liter (3 cup)
lidded and shrouded tin can. Cooking is pretty much
“set it and forget it” until final flame-out when the
chimney is removed, the food can lowered to just above
the coals, and the entire stove placed into an
insulated 5-gallon plastic pail where cooking can
continue. This extinguishes the coals which can then
be saved as char containing roughly 1/2 the energy of
the original fuel.

This design is intended for refugee camps, disaster
victims, and people too poor to be ashamed to be seen
cooking with tin cans. So far, it all works some of
the time, and some of it works all of the time. It’s
not rocket science, pursuit of perfection, or striving
to be best. Maybe its quality, good, or at least good
enough. Maybe it hits the mark, but maybe the wrong
mark. Maybe someone can use some part of this to
reach their goals.

Respectfuly,

Dick Boyt

__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free web site building tool. Try it!
http://webhosting.yahoo.com/ps/sb/

From tmiles at TRMILES.COM Sun Jan 25 16:43:52 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:49 2004
Subject: Tiled Stove with wateraccumulator
Message-ID: <SUN.25.JAN.2004.134352.0800.TMILES@TRMILES.COM>

This heat exchanger may be of interest to the list.

Tom Miles

----- Original Message -----
From: "Sven Westerlund" <sven_westerlund@hotmail.com>
Sent: Sunday, January 25, 2004 1:07 PM
Subject: Tiled Stove with wateraccumulator

> Wanted
>
> An serious American / Canadian manufacturer and distributor, including
> marketing, of our US Patent no 6145500 (date of patent Nov 14 2000) which
is
> a home boiler, welded in steel, furniture designed and known in Sweden as
> Kakelugn Gripsholm. This model has a large inbuilt water accumulator as
well
> as an inbuilt heat exchanging which can provide all household waterborne
> heating and hot water supply. The boiler can also be used as a detached
> stove. Separate from heating/hot water systems, providing 24 hour heating.
>
> The boiler comes complete with exterior tiling, Swedish style, which can
be
> replaced by slate or simply painted. It has been passed by the Swedish
> boards of safety and environment.
>
> Swedish customers praise the product very highly mainly because everything
> is inbuilt in a furniture designed construction with a high efficiency
> allowing in to be placed in one of the larger rooms of the house. The
boiler
> is very easy to install, no extra room is needed. And extremely economize
on
> wood heating by high efficiency, with adjustable outgoing
> smokegastemperature. And also the fact that water is one of the most
> effective medium to store heat into, further also give the most pleasant
> warming to your house. This boiler could also give hot air fast for quick
> warm up.
>
> It's also a reward to the person/persons who can provide genuine contact
> with a serious American/Canadian manufacturer and distributor of this
> product
>
> If you have any tip or question about this, contact me by mail
>
> Pictures and more information visit www.pckart.se/wemek
> Sven_Westerlund@hotmail.com

From ventfory at IAFRICA.COM Mon Jan 26 04:48:13 2004
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:49 2004
Subject: Chimneys - cleaner top-lighting start-ups
Message-ID: <MON.26.JAN.2004.114813.0200.VENTFORY@IAFRICA.COM>

John, Crispin, Ron,

John, even though we are practically neighbours, we have never communicated. I think due to the fact that we stood nothing to gain from each other apart from what was posted already and we are quite happy to learn from others across the seas.

I think your stove has the potential to revolutionize indoor cooking on the Reef, one day, not so far away.

If I could just comment on some of your points, unfortunately not relating much to chimneys but more on cleaner ways of top lighting gasifiiers, but especially, stubborn coal and charcoal gasifiers:

> Smoke was produced during the first minute but slightly less than with
wood
> and of a shorter time duration. This is attributed to the fact that the
> stove is not receiving enough secondary air to consume all the gasses.
> ( originating from paraffin and wood ) This was the lighting method that
> Crispin observed,
>

As with your coal stove I also find paraffin (liquid) is the best way to get the top layer of my charcoal stove to glow, before it takes off. Achieving only one minute of heavier smoke release is quite unbelievable, perhaps due to your high induced draft (high chimney). Mine takes 3 - 4 minutes, with a 40 cm high internal chimney. I am also attempting to reduce the smoke released at start-up (see idea below), athough current emissions appears to be within acceptable comfort limits of peri-urban users. Even though my stove weighs less than 10 kg and is portable (no external chimney), the users don't seem to mind the slightly hazy smoke at start-up at all, but do open doors and windows in the kitchen during start-up.

As Crispin rightly said, Alcohol (I would recommend ethanol gel in S.Africa), produces significantly less visible smoke, but having a heating value of 30 MJ/kg compared to the 46 MJ/kg for paraffin, it does take longer to light the 'coals'. Even though ethanol gel is considered expensive it does give remarkably long burns and will be more cost-effective in the long run, compared to paraffin, but availability is a problem at the moment. If one considers that _methanol_ gel has been available for ages, and is much sought after in poor areas, ethanol could easily do the same and being non-toxic...

I learned in the SA version of Popular Mechanics of a unique and inexpensive way of igniting charcoal. Take used tea bags (just get into the habit of placing them to one side after use), leave them to dry outside and then soak them in paraffin. Each tea bag burns for up to 5 minutes and two or so are all that is needed to top light a charcoal fire. Try them in a barbeque, they really work well! I use them all the time, and lately also to top light Richards' non-woody paper/sawdust briquettes.

> Conclusion.
> One could add another secondary air system to handle the light up
condition
> and achieve perfection, but this will add to the stove cost and complexity
> of operating it. Where a simple control system is called for This is not
> considered necessary as the initial smoke is of a relatively small volume
> and of short time duration, compared to the total burn time of up to 8
> hours.

Even having only a short burst of smoke at start-up, I still think you might benefit from a new design I have been working on, especially since your stove is immovable. I supply secondary air to multiple inlets and it does not cost much extra, nor does it need a control system.

It consists of a metal sleeve which is designed to fit around the combustion chamber, with at least a 1cm gap for air to travel up into. Secondary air is channelled in through holes on the outer perimeter, and passes below a single dividing plate which supports the insulation above and then enters into the base of the metal sleeve, adjacent to the fuel bed.

The air is then sucked up into the sleeve, pre-heated and then distributed to any number of air inlets higher up. The holes are drilled into the chamber, I use ceramic, but metal will also do, at set intervals. During start-up, air will travel directly to the air holes adjacent to the burning paraffin layer. This should result in less CO and unburned carbon particles being released. As the burn continues downward the other inlet holes lower down will eventually supply the air where needed.

Since thinking up this latest design I have moved away from having several dividing plates, as can be seen in my first briquette stove I built for Richard Stanley, to feed in air at set intervals. All in all, stoves using these sleeves are easier to assemble, less costly, and are perfect for ever changing prototypes. Before, adding dividing plates also caused breaks in the surrounding insulation, leading to hot spots forming on the outside of the stove. Replacing the combustion chamber now is a dream, having no contact with the insulation. I have a JPEG drawing.

Regards

Kobus
ventfory@iafrica.com

From takeda at SONIC.NET Mon Jan 26 05:16:02 2004
From: takeda at SONIC.NET (Matthew Takeda)
Date: Tue Aug 10 18:30:49 2004
Subject: Rocket Science, Rocket Engineering and Cookstove Design
In-Reply-To: <200401210500.i0L50Ov25823@ns1.repp.org>
Message-ID: <MON.26.JAN.2004.021602.0800.TAKEDA@SONIC.NET>

Warren Bollmeier wrote:
>I am wondering if we have given enough thought to the
>design of input channel? Here is why I think this might be one area to
>investigate further. It has been suggested that combustion will be
>enhanced by mixing and that got me to thinking maybe if we increased the
>turbulence in the input channel? Thus might be done by roughening the
>surface of the input channel, much like is done to increase the turbulence
>on the top of airplane wings to keep the flow attached.

I've been working on a very small gasifier stove and have been thinking of
using vortex generators to increase turbulence where the secondary air is
introduced.

Matthew Takeda
the JOAT
From crispin at NEWDAWN.SZ Mon Jan 26 12:18:48 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:49 2004
Subject: Rocket Science, Rocket Engineering and Cookstove Design
Message-ID: <MON.26.JAN.2004.191848.0200.CRISPIN@NEWDAWN.SZ>

Dear Matthew

>I've been working on a very small gasifier stove and have
>been thinking of using vortex generators to increase
>turbulence where the secondary air is introduced.

I agree with this approach. I will be discussing that during my brief
presentation at the ETHOS meeting. Some very agreeable things happen when
you induce and maintain a vortex.

After the initial scramble to get going, the fire settles down and can be
made by various means to keep spinning in the centre of a round chamber.

Sincerely
Crispin

From monogle at OREGONCOAST.COM Mon Jan 26 14:13:51 2004
From: monogle at OREGONCOAST.COM (Damon Ogle)
Date: Tue Aug 10 18:30:49 2004
Subject: Insulative Ceramics
Message-ID: <MON.26.JAN.2004.111351.0800.MONOGLE@OREGONCOAST.COM>

Dear Kanchan,
I am glad to hear that you are finding our article useful. We would
be very interested in all the information you might have on the
insulative bricks you have made.
How were the "porous mud/wax" bricks made? Were they successful?
Did you determine densities? I find that the density of the brick
(weight in grams / volume in cubic centimeters ) is one of the best
indicators of the suitability of the material. As was mentioned in the
article, we try to achieve a density between 0.8 and 0.4 grams/cc.
Local brickmakers and potters (especially the older folks) can be a
treasure trove of information about how to use local materials to make
good ceramics. Often they alter the local muds by processing them and
adding small amounts of other materials to form a good clay "body". The
additives may include special sands, ashes, and even stranger things
like dung or molasses. They won't be able to explain why things work,
but they will know what does work. I have had good luck using their
clay bodies and adding my own fillers to make lightweight bricks.
I can't resist adding a bit of historical trivia. The Hagia Sophia
church/mosque in Istanbul was built in the middle of the first millenium
and had the largest dome in the world for many centuries. It was built
using special light-weight bricks from the island of Rhodes. It was
said that 5 of the bricks from Rhodes weighed the same a one regular
brick. I wish I had that recipe for making bricks!
Good luck with your project.

Damon Ogle

From andrew.heggie at DTN.NTL.COM Mon Jan 26 15:09:42 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:50 2004
Subject: Rocket Science, Rocket Engineering and Cookstove Design
In-Reply-To: <005201c3e430$a4d213a0$2a47fea9@md>
Message-ID: <MON.26.JAN.2004.200942.0000.>

On Mon, 26 Jan 2004 19:18:48 +0200, Crispin wrote:

>Dear Matthew
>
>>I've been working on a very small gasifier stove and have
>>been thinking of using vortex generators to increase
>>turbulence where the secondary air is introduced.
>
>I agree with this approach. I will be discussing that during my brief
>presentation at the ETHOS meeting. Some very agreeable things happen when
>you induce and maintain a vortex.

As you know I have been using a cyclone type burner for some time,
Ronal saw an early version. This ability to "hold" a flame in mid
space so that it can burn out without impinging on surfaces is useful.
There are many effects happening here but I feel it is inherently a
high excess air device. Now this does not matter in industrial type
applications but it may have two disadvantages in a small cook stove,
one is the cost of powering the air flow (especially bearing in mind
the need to supply an excess). The other is interesting to me. Both
Alex English and I experimented with powered secondary air, I believe
we both used compressed air jets initially. Now these are expensive
overkill but they do allow a hugh energy low volume jet of air.

I was keen to force the flame into a flat "swirl" in order to burn it
out in a low height, before it reached the pot. The funny thing is the
vortex was maintained to the point where the "dilution" air spilled
out of the side of the stove. When I added my kelly kettle ( whereby
the flue gases pass up inside the kettle) this effectively entrained
this dilution air, which in turn entrained the flame up the middle of
the kettle. I am sure this severely reduced the ability of the
internal heat exchange surface to gain heat from the flame, which also
continued burning past the top of the kettle. So I think there is a
need to break the vortex or drastically reduce the excess air by some
sort of pre mixing.
>
>After the initial scramble to get going, the fire settles down and can be
>made by various means to keep spinning in the centre of a round chamber.

Are any of these various means non powered?

AJH

From hseaver at CYBERSHAMANIX.COM Mon Jan 26 17:46:11 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex (was Rocket Science,
Rocket Engineering and Cookstove Design)
In-Reply-To: <7tpa10daab2lpsvfhk2iiin3lcpe14vb36@4ax.com>
Message-ID: <MON.26.JAN.2004.164611.0600.HSEAVER@CYBERSHAMANIX.COM>

Have any of you read any of the works of Viktor Shauberger, more or less the
father of vortex technology? Fascinating stuff. I'd think from what little I've
read that it would be fairly simple to induce a vortex with the use of properly
designed nozzles that wouldn't need power other than the natural draft.
Do a google on "viktor schauberger" vortex air

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

From dstill at EPUD.NET Mon Jan 26 18:53:52 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex
In-Reply-To: <20040126224611.GA11847@cybershamanix.com>
Message-ID: <MON.26.JAN.2004.155352.0800.DSTILL@EPUD.NET>

Dear Harmon,

We spent three days at an ETHOS stove seminar trying to improve mixing using
only natural draft but with no great success. It is possible to induce swirl
in the flame but in our experiments the gentle swirl was not enough to
significantly clean up smoke. Larry Winiarski points out that we want is
good mixing where fuel, air, spark are thoroughly and evenly distributed. I
figure that the air in a Rocket combustion chamber is rising at around three
to four miles per hour. This very gentle wind doesn't give us much of an
engine to passively create mixing. But I think that mixing is the key to
improved emissions and hope that someone figures out a practical method
applicable to 3rd world stoves.

All Best,

Dean

From ronallarson at QWEST.NET Mon Jan 26 19:32:43 2004
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:50 2004
Subject: Fw: ETHOS conference--shuttle ride from airport
Message-ID: <MON.26.JAN.2004.173243.0700.RONALLARSON@QWEST.NET>

Stovers:

Apologies to all for a message that may only be of interest to a few.

Anyone coming in at the Sea-Tac airport at about 7:00 PM this coming
Friday night - and interested in sharing a ride?

Ron

----- Original Message -----
From: Amy Holland <aholland@iastate.edu>
To: <ronallarson@qwest.net>
Sent: Monday, January 26, 2004 10:35 AM
Subject: ETHOS conference--shuttle ride from airport

> Hello,
>
> This is to provide you with instructions for getting a shuttle from the
> airport to the hotel. The shuttle service is located on the third floor
> of the parking garage at the Seattle-Tacoma airport. There are red and
> black ground transportation signs throughout the airport--follow these.
> The cost is $21 for a single rider. If you have others riding with you,
> the cost for a second rider is $10 and every passenger after that is $6
> each. You may pay the driver with cash, check, or credit card.
>
> If you have any further questions, please let me know.
>
> Thanks, and see you in Seattle!
>
> Amy
>
>
>

From tombreed at COMCAST.NET Mon Jan 26 19:41:29 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:50 2004
Subject: Natural vs forced convection
Message-ID: <MON.26.JAN.2004.174129.0700.TOMBREED@COMCAST.NET>

Dear Dean and All:

We first developed the top lit updraft gasifier stove in 1986 with forced
(lab air) convection. I spent the next twelve years trying to achieve good
air/fuel mixing with natural draft. Maybe you can solve it, but I decided
to get on with the job. (Sometimes the "best" 9ie cheapest is the enemy of
the good, more expensive but works much better).

In 1998 I tried forced convection (~ 1 watt of blower or fan) and within a
week had the beginnings of our woodgas campstove.

Good luck in getting hot pyrolysis vapors to mix with hot or cold lazy air.

Yours truly, TOM REED
----- Original Message -----
From: "Dean Still" <dstill@EPUD.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, January 26, 2004 4:53 PM
Subject: Re: [STOVES] Vortex

> Dear Harmon,
>
> We spent three days at an ETHOS stove seminar trying to improve mixing
using
> only natural draft but with no great success. It is possible to induce
swirl
> in the flame but in our experiments the gentle swirl was not enough to
> significantly clean up smoke. Larry Winiarski points out that we want is
> good mixing where fuel, air, spark are thoroughly and evenly distributed.
I
> figure that the air in a Rocket combustion chamber is rising at around
three
> to four miles per hour. This very gentle wind doesn't give us much of an
> engine to passively create mixing. But I think that mixing is the key to
> improved emissions and hope that someone figures out a practical method
> applicable to 3rd world stoves.
>
> All Best,
>
> Dean

From elk at WANANCHI.COM Mon Jan 26 23:50:31 2004
From: elk at WANANCHI.COM (Elsen Karstad)
Date: Tue Aug 10 18:30:50 2004
Subject: Cookstove Design- vortex
Message-ID: <TUE.27.JAN.2004.075031.0300.ELK@WANANCHI.COM>

While designing the large combustion chamber for my down-draught open-pit
carboniser, I experimented with different air/gas mixing strategies in order
to most efficiently burn off the volatiles- the white smoke- produced from
the carbonisation of particulate biomass (sawdust at the time). Following
the rule that most efficient combustion occurs when you maximise 1) dwell
time 2) mixing and 3) temperature, I started off with a vortex but soon
found that totally random mixing worked very much better.

I concluded that a while vortex forces air/gas into a more horizontal spiral
path, which should prolong the dwell-time as opposed to a more direct
vertical path through the combustion zone, it also increases air/gas speed
and reduces mixing due to the more orderly laminar flow arrangement.

A spiral flame may be attractive pyrotechnics, but it has it's drawbacks.

elk

From jeff.forssell at CFL.SE Tue Jan 27 06:50:22 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
Message-ID: <TUE.27.JAN.2004.125022.0100.JEFF.FORSSELL@CFL.SE>

I read something called (in swedish) "Living water" that was interesting, but I wasn't sure how much was true and how much was wishful thinking. At the end they talked about American military sneaking away with his stuff after WWII, but if it were all it was said to be, they wouldn't need to be so keen on controlling the worlds oil supply.

There's an amusing anecdote about how Shauberger took a doubting scientist and waded out in a stream to measure the temperature behind a stone that water swirled around and, I believe, he said that it would be lower and the scientist said it wopuld be higher. Shauberger was according to the book right. When I suggested to an enthusiastic "vortexite" that we go down to the stream behind my house and try ourselves, he wasn't interested. A good story (=scientists don't know it all) is better than a good experiment for most people.

(I suspect the temperatur difference would be extremely difficult to measure at all. I think I tried a quicky myself to make sure, but because I didn't expect much I didn't try very hard. Any other experience?)

> -----Original Message-----
> From: Harmon Seaver [mailto:hseaver@CYBERSHAMANIX.COM]
> Sent: Monday, January 26, 2004 11:46 PM
> To: STOVES@LISTSERV.REPP.ORG
> Subject: [STOVES] Vortex (was Rocket Science, Rocket Engineering and
> Cookstove Design)
>
>
> Have any of you read any of the works of Viktor
> Shauberger, more or less the
> father of vortex technology? Fascinating stuff. I'd think
> from what little I've
> read that it would be fairly simple to induce a vortex with
> the use of properly
> designed nozzles that wouldn't need power other than the
> natural draft.
> Do a google on "viktor schauberger" vortex air
>
>
> --
> Harmon Seaver
> CyberShamanix
> http://www.cybershamanix.com
>

From krishnakumar_07 at YAHOO.CO.UK Tue Jan 27 09:11:32 2004
From: krishnakumar_07 at YAHOO.CO.UK (=?iso-8859-1?q?krishna=20kumar?=)
Date: Tue Aug 10 18:30:50 2004
Subject: NDG
Message-ID: <TUE.27.JAN.2004.141132.0000.KRISHNAKUMAR07@YAHOO.CO.UK>

I would like to know how to calculate the
final mass of ash in the water boiling test.

=====
krish

________________________________________________________________________
BT Yahoo! Broadband - Free modem offer, sign up online today and save ?80 http://btyahoo.yahoo.co.uk

From tombreed at COMCAST.NET Tue Jan 27 09:30:08 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
Message-ID: <TUE.27.JAN.2004.073008.0700.TOMBREED@COMCAST.NET>

Dear Jeff and All:

I don't know if a water vortex cools or heats, but James Prescott Joule
(1816-1889) connected a water bath with paddles to a falling weight with
pulleys and measured the mechanical equivalent of heat - 4.186 Joules/cal.
He thereby made himself immortal and freed us from guessing.

Previously Benjamin Thompson of Woburn Mass., later Count Rumford had
observed (but not measured accurately) this equivalence in the boring of
cannons.

We stand on the shoulders of giants.

A well planned experiment can open the eyes of civilization for all times.
"Patch on patch" thinking ultimately slows you down.

Onward...

TOM REED

----- Original Message -----
From: "Jeff Forssell" <jeff.forssell@CFL.SE>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, January 27, 2004 4:50 AM
Subject: Re: [STOVES] Vortex "believer" or experiement

> I read something called (in swedish) "Living water" that was interesting,
but I wasn't sure how much was true and how much was wishful thinking. At
the end they talked about American military sneaking away with his stuff
after WWII, but if it were all it was said to be, they wouldn't need to be
so keen on controlling the worlds oil supply.
>
> There's an amusing anecdote about how Shauberger took a doubting scientist
and waded out in a stream to measure the temperature behind a stone that
water swirled around and, I believe, he said that it would be lower and the
scientist said it wopuld be higher. Shauberger was according to the book
right. When I suggested to an enthusiastic "vortexite" that we go down to
the stream behind my house and try ourselves, he wasn't interested. A good
story (=scientists don't know it all) is better than a good experiment for
most people.
>
> (I suspect the temperatur difference would be extremely difficult to
measure at all. I think I tried a quicky myself to make sure, but because I
didn't expect much I didn't try very hard. Any other experience?)
>
>
> > -----Original Message-----
> > From: Harmon Seaver [mailto:hseaver@CYBERSHAMANIX.COM]
> > Sent: Monday, January 26, 2004 11:46 PM
> > To: STOVES@LISTSERV.REPP.ORG
> > Subject: [STOVES] Vortex (was Rocket Science, Rocket Engineering and
> > Cookstove Design)
> >
> >
> > Have any of you read any of the works of Viktor
> > Shauberger, more or less the
> > father of vortex technology? Fascinating stuff. I'd think
> > from what little I've
> > read that it would be fairly simple to induce a vortex with
> > the use of properly
> > designed nozzles that wouldn't need power other than the
> > natural draft.
> > Do a google on "viktor schauberger" vortex air
> >
> >
> > --
> > Harmon Seaver
> > CyberShamanix
> > http://www.cybershamanix.com
> >

From kchisholm at CA.INTER.NET Tue Jan 27 09:24:13 2004
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
Message-ID: <TUE.27.JAN.2004.102413.0400.KCHISHOLM@CA.INTER.NET>

Dear Jeff
----- Original Message -----
From: "Jeff Forssell" <jeff.forssell@CFL.SE>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, January 27, 2004 7:50 AM
Subject: Re: [STOVES] Vortex "believer" or experiement

>
> There's an amusing anecdote about how Shauberger took a doubting scientist
and waded out in a stream to measure the temperature behind a stone that
water swirled around and, I believe, he said that it would be lower and the
scientist said it wopuld be higher. Shauberger was according to the book
right. When I suggested to an enthusiastic "vortexite" that we go down to
the stream behind my house and try ourselves, he wasn't interested. A good
story (=scientists don't know it all) is better than a good experiment for
most people.
>
> (I suspect the temperatur difference would be extremely difficult to
measure at all. I think I tried a quicky myself to make sure, but because I
didn't expect much I didn't try very hard. Any other experience?)
>
It is hard to go wrong if you "believe" the Laws of Thermodynamics. The
First and Second Laws stare, in effect:
First Law: You can't get something for nothing.
Second Law: As a matter of fact, you can't break even.

The case of the water swirling behind a rock is very simple as presented:
the water temperature behind the rock would be higher, in that mechanical
energy would be converted into heat as a result of turbulence. In Imperial
Units, it takes 778 ft-lbs of energy to make 1 BTU. The temperature rise
would be relatively small in the turbulence zone behind the rock, and it
would be very difficult to measure water temperature differences.

Best wishes,

Kevin

From a31ford at INETLINK.CA Tue Jan 27 09:37:17 2004
From: a31ford at INETLINK.CA (a31ford)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiment (From stoves side)
In-Reply-To: <D11530EDCDC91E4DA22CDD64EEDE0F726860FC@TOR.cfl.local>
Message-ID: <TUE.27.JAN.2004.083717.0600.A31FORD@INETLINK.CA>

Hello all,

This message, was on the stoves side of things, but applies to gasifiers as
well
(sorry to those that subscribe to both), so I've posted my reply,
and started it on GASL also,
(might be interesting to see the two "sides" of things, so to speak).

The post below, I believe, for one simple fact, anything that has to move
faster "air
over a plane's wing", "wind around a round building (like a grainery)",
"the old science class "blowing out a candle on the far side of a glass,
thing", etc.
as the air has to move (or water it the case below) faster to get around, I
can see
that it would give up some of it's heat in the process to the surface it's
moving on,
and the other medium around it, when reaching the "far" side it would be
cooler, not
that we want any of this side of the effect, but simply agreeing with the
comment below.

On gasifiers, my thoughts are in agreement to vortex style air, BUT, note
the following:

Elk, had a test where air vortex in a charcoal maker, (see post > Stoves,
cookstove-vortex < )
his/her?? (assuming his) notes are that the vortex causes the velocity of
the air to speed up,
thereby making the residence time shorter (I agree with this also).

However, in gasification (downdraft in particular) the air is "injected"
above
the pyrolysis area and in this case, the flow is "PRE", therefore,
retention
time is not a factor, however, once the air IS in the pyrolysis
zone/reduction zone,
retention time DOES become a factor (are we, in using a throat, "cutting
our noses off" ??)
I have a smaller test gasifier, sitting on a bench in my shop, I think I
will try running
the unit un-throated "so to speak", rather, I'll simply place the vortex
nozzles higher up
the gasifier (this unit is in ring sections, bolted together, and is quite
easy to reconfigure)
causing a longer retention time of air before the ash (leaving the current
throat & ash area the same).
I can see a problem in this, simply that it will most likely "slag" simply
because the unit is not
designed to run with the nozzles that high, but I simply want to try it
anyhow, just "because" (yes I'm board).

I think the difference here (between Elk's findings, and gasifiers) is that
in the world of gasifiers,
the vortex is "wanted" BEFORE, the area where pyrolysis becomes reduction,
and once we enter the reduction zone, we want retention time,
after that I would assume that speed is the preferred air flow, in the
final stages.

Greg Manning,
Brandon, Manitoba, Canada

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf Of Jeff Forssell
Sent: Tuesday, January 27, 2004 5:50 AM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Vortex "believer" or experiement

I read something called (in swedish) "Living water" that was interesting,
but I wasn't sure how much was true and how much was wishful thinking. At
the end they talked about American military sneaking away with his stuff
after WWII, but if it were all it was said to be, they wouldn't need to be
so keen on controlling the worlds oil supply.

There's an amusing anecdote about how Shauberger took a doubting scientist
and waded out in a stream to measure the temperature behind a stone that
water swirled around and, I believe, he said that it would be lower and the
scientist said it wopuld be higher. Shauberger was according to the book
right. When I suggested to an enthusiastic "vortexite" that we go down to
the stream behind my house and try ourselves, he wasn't interested. A good
story (=scientists don't know it all) is better than a good experiment for
most people.

(I suspect the temperatur difference would be extremely difficult to measure
at all. I think I tried a quicky myself to make sure, but because I didn't
expect much I didn't try very hard. Any other experience?)

From a31ford at INETLINK.CA Tue Jan 27 09:54:52 2004
From: a31ford at INETLINK.CA (a31ford)
Date: Tue Aug 10 18:30:50 2004
Subject: FW: [STOVES] Vortex "believer" or experiment (From stoves side)
Message-ID: <TUE.27.JAN.2004.085452.0600.A31FORD@INETLINK.CA>

My first post when where ??
Greg

-----Original Message-----
From: a31ford [mailto:a31ford@inetlink.ca]
Sent: Tuesday, January 27, 2004 8:37 AM
To: 'Jeff Forssell'; A Gasification List (E-mail);
'stoves@listserv.repp.org'
Subject: RE: [STOVES] Vortex "believer" or experiment (From stoves side)

Hello all,

This message, was on the stoves side of things, but applies to gasifiers
as well(sorry to those that subscribe to both), so I've posted my reply,
and started it on GASL also,
(might be interesting to see the two "sides" of things, so to speak).

The post below, I believe, for one simple fact, anything that has to
move faster "air over a plane's wing", "wind around a round building
(like a grainery)", "the old science class "blowing out a candle on
the far side of a glass, thing", etc. as the air has to move (or water in
the case below) faster to get around, I can see that it would give up
some of it's heat in the process to the surface it's moving on, and the
other medium around it, when reaching the "far" side it would be cooler, not
that we want any of this side of the effect, but simply agreeing with the
comment below.

On gasifiers, my thoughts are in agreement to vortex style air,
BUT, note the following:

Elk, had a test where air vortex in a charcoal maker,
(see post > Stoves, cookstove-vortex < )
his/her?? (assuming his) notes are that the vortex causes the velocity
of the air to speed up, thereby making the residence time shorter.
(I agree with this also).

However, in gasification (downdraft in particular) the air is "injected"
above the pyrolysis area and in this case, the flow is "PRE", therefore,
retention time is not a factor, however, once the air IS in the
pyrolysis zone/reduction zone, retention time DOES become a factor
(are we, in using a throat, "cutting our noses off" ??) I have a smaller
test gasifier, sitting on a bench in my shop, I think I will try running
the unit un-throated "so to speak", rather, I'll simply place the vortex
nozzles higher up the gasifier (this unit is in ring sections,
bolted together, and is quite easy to reconfigure) causing a longer
retention time of air before the ash.
(leaving the current throat & ash area the same).

I can see a problem in this, simply that it will most likely "slag"
simply because the unit is not designed to run with the nozzles that high,
but I simply want to try it anyhow, just "because" (yes I'm board).

I think the difference here (between Elk's findings, and gasifiers)
is that in the world of gasifiers, the vortex is "wanted" BEFORE, the area
where pyrolysis becomes reduction, and once we enter the reduction zone,
we want retention time, after that I would assume that speed is the
preferred air flow, in the final stages.

Greg Manning,
Brandon, Manitoba, Canada

I read something called (in swedish) "Living water" that was interesting,
but I wasn't sure how much was true and how much was wishful thinking. At
the end they talked about American military sneaking away with his stuff
after WWII, but if it were all it was said to be, they wouldn't need to be
so keen on controlling the worlds oil supply.

There's an amusing anecdote about how Shauberger took a doubting scientist
and waded out in a stream to measure the temperature behind a stone that
water swirled around and, I believe, he said that it would be lower and the
scientist said it wopuld be higher. Shauberger was according to the book
right. When I suggested to an enthusiastic "vortexite" that we go down to
the stream behind my house and try ourselves, he wasn't interested. A good
story (=scientists don't know it all) is better than a good experiment for
most people.

(I suspect the temperatur difference would be extremely difficult to measure
at all. I think I tried a quicky myself to make sure, but because I didn't
expect much I didn't try very hard. Any other experience?)

From a31ford at INETLINK.CA Tue Jan 27 09:56:57 2004
From: a31ford at INETLINK.CA (a31ford)
Date: Tue Aug 10 18:30:50 2004
Subject: Double post
Message-ID: <TUE.27.JAN.2004.085657.0600.A31FORD@INETLINK.CA>

Sorry all, I thought my post was "Wind in the wind"
didn't mean to post twice.

Greg Manning

From michelandi at GMX.DE Tue Jan 27 10:11:08 2004
From: michelandi at GMX.DE (Andreas MICHEL)
Date: Tue Aug 10 18:30:50 2004
Subject: Controlled Cooking Test - measurement devices/experience
Message-ID: <TUE.27.JAN.2004.161108.0100.MICHELANDI@GMX.DE>

Hi,

I'm Andi, student at University of Oldenburg/Germany (Renewable Enegies).

Soon I will be in Lesotho to do some controlled cooking tests on ICS in
schools. By preparing these tests I wonder about the measurement devices that I
will need, espacially about the needed accuracy.
- What about the weight measuring? Which should be the smallest unit of my
balance to measure
1. wood consumption and
2. weight of the food (before and after cooking)?
- How to measure moisture content of the fuelwood? So far, I think that I
will use some hygrometer ( eg Protimeter mini). Here the accuracy is the
question again? Any favorit devices from your side? What if there are different
moisture contents due to different wood types?

Thank you very much for assistance!

Andi

--
*********************
CARPE DIEM

ANDREAS MICHEL
Brommystr. 3
26121 Oldenburg
0441-8852751
michelandi@gmx.de
*********************

+++ GMX - die erste Adresse f?r Mail, Message, More +++
Bis 31.1.: TopMail + Digicam f?r nur 29 EUR http://www.gmx.net/topmail

From psanders at ILSTU.EDU Tue Jan 27 10:45:00 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:50 2004
Subject: Natural vs forced convection
In-Reply-To: <016d01c3e46f$1f3362f0$6401a8c0@TOM>
Message-ID: <TUE.27.JAN.2004.094500.0600.PSANDERS@ILSTU.EDU>

Stovers,

After meeting Tom Reed in 2001, I started work on natural convection in the
small gasifiers. My natural-draft "Juntos stoves" have been shown and will
be at the ETHOS meeting. I claim "reasonable success" with natural
convection. And most recently I have been working with Agua Das on natural
convection of his "Dasifier", again with noteworthy success.

Although I am also a believer in the great power of forced convection, the
realities of many (not all) Third World countries do justify further
efforts on natural convection.

Paul

At 05:41 PM 1/26/04 -0700, TBReed wrote:
>Dear Dean and All:
>
>We first developed the top lit updraft gasifier stove in 1986 with forced
>(lab air) convection. I spent the next twelve years trying to achieve good
>air/fuel mixing with natural draft. Maybe you can solve it, but I decided
>to get on with the job. (Sometimes the "best" 9ie cheapest is the enemy of
>the good, more expensive but works much better).
>
>In 1998 I tried forced convection (~ 1 watt of blower or fan) and within a
>week had the beginnings of our woodgas campstove.
>
>Good luck in getting hot pyrolysis vapors to mix with hot or cold lazy air.
>
>Yours truly, TOM REED
>----- Original Message -----
>From: "Dean Still" <dstill@EPUD.NET>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Monday, January 26, 2004 4:53 PM
>Subject: Re: [STOVES] Vortex
>
>
> > Dear Harmon,
> >
> > We spent three days at an ETHOS stove seminar trying to improve mixing
>using
> > only natural draft but with no great success. It is possible to induce
>swirl
> > in the flame but in our experiments the gentle swirl was not enough to
> > significantly clean up smoke. Larry Winiarski points out that we want is
> > good mixing where fuel, air, spark are thoroughly and evenly distributed.
>I
> > figure that the air in a Rocket combustion chamber is rising at around
>three
> > to four miles per hour. This very gentle wind doesn't give us much of an
> > engine to passively create mixing. But I think that mixing is the key to
> > improved emissions and hope that someone figures out a practical method
> > applicable to 3rd world stoves.
> >
> > All Best,
> >
> > Dean

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 Jan 27 11:27:54 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:50 2004
Subject: Chimneys
In-Reply-To: <003001c3e1f8$10cb3e00$d75afea9@net>
Message-ID: <TUE.27.JAN.2004.102754.0600.PSANDERS@ILSTU.EDU>

John,

Try this to start your stove:

Get some of that "gel-fuel" made from sugar cane and now being promoted in
Africa and elsewhere.

For the first time, yesterday, I use it to start my small wood gasifier and
it was truly VERY good. Even better than the citronella fluid that I have
used to soak the starter fuel (chips or corn cobs.)

Paul

At 11:27 PM 1/23/04 +0200, John Davies wrote:
>----- Original Message -----
>From: "Crispin" <crispin@newdawn.sz>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Thursday, January 22, 2004 4:40 PM
>Subject: Re: [STOVES] Chimneys
>
>
> > Dear John
>
> > I have a feeling that lighting a coal stove might be done 'cleanly' if
> > alcohol was used instead of paraffin. Have you tried that and was there a
> > noticeable difference?
>
>As you have seen the stove in action, you will agree that the initial
>combustion of the paraffin ( illiminating Kerosene ) is far from complete.
>the same applies to a lesser extent, to the firewood used as a starter, with
>the combustion running away at this point, and producing smoke for the first
>minute or so. This extremely high combustion rate is necessary to heat the
>top layer of coal to combustion temperature. We have here the problem of
>burning wood and kerosene in a stove that is not designed for it.
>
>Now taking the target user into consideration, paraffin is a familiar fuel
>and does not form an explosive mixture in the stove. It is also freely
>available and a cheaper fuel. I have not tried using alcohol for this very
>reason, but am sure that it would reduce that initial smoke.
>
>In terms of deviating from the current standard lighting method, I would be
>more inclined to do some tests using paper instead of the paraffin, as this
>is more likely to be tried out by the user.
>
> > WOuld it be possible to conclude that a _really_ clean chimney wouldn't
>last
> > as long as a dirty one if the combustion wasn't all that good (i.e.
> > 'ordinary'?
>
>Would it not ? This is what I am trying to find out. Each lighting of my
>stove starts ordinary and then goes onto good soot free combustion, no
>chance of blocking the chimney but a very light soot coating at each start
>up.
>
>Keep them burning, Clean and hot.
>
>John Davies.

From Kanchan at KU.EDU.NP Tue Jan 27 22:46:24 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:30:50 2004
Subject: insulative ceramics
Message-ID: <WED.28.JAN.2004.093124.0545.KANCHAN@KU.EDU.NP>

Dear Damon and Dan,
Thanks for your response. I have had these files put on following
webpage. You can download from there. I'll appreciate your comments ,
suggestions and advice.

www.geocities.com/kanresearch2004
Then click on "Ppt" folder
There are 2 Ppt files, they are same file due to large in size divided
into 2. Before reading merge into one.

kanchan

From crispin at NEWDAWN.SZ Tue Jan 27 15:24:07 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
Message-ID: <TUE.27.JAN.2004.222407.0200.CRISPIN@NEWDAWN.SZ>

Dear Jeff

The US military reportedly did a lot of experimenting on vortexes around
ship after WWII. There is a guy selling snake-oil air conditioning
retro-fit devices that are suppose to make money with a vortex. I met him
in Barbados at the UN conference for Small Island Developing States. (SIDS).
We both had technology booths at the airport. You can store/entrain energy
in a vortex at a lower forward speed than in laminar flow which is why they
tend to form and self-perpetuate (I think!). Somehow it is a 'lower energy
condition' while retaining the same total momentum - can't remember the
correct phrase. Spinning skaters crossed with hanging pendulums or
something.

A low velocity chimney vortex is more turbulent than a low velocity
quasi-laminar flow in the same chimney and has a lower forward pressure drop
(flow resistance). I inherited a book on this from my father - perhaps I
should read it again.

As for your stream temperature measuring non-event, remember that contrary
popular opinion, much of science is founded on belief, not evidence!

Regards
Crispin

From crispin at NEWDAWN.SZ Tue Jan 27 15:34:08 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:50 2004
Subject: Controlled Cooking Test - measurement devices/experience
Message-ID: <TUE.27.JAN.2004.223408.0200.CRISPIN@NEWDAWN.SZ>

Dear Andi

I suggest a scale of 2gm accuracy, about 12 to 20 kg capacity to test the
whole stove and pot together.

It is useful to have battery operated scales. You can buy them in
Johannesburg at Dick King Lab Supplies if you want. They have small battery
powered scales (for example 400gm +-1) which are about the size and shape of
a paperback book. Good for weighing food and wood.

I would not trust a meter for water content of wood. I would simply cut out
a sample and weigh it, dry it in a small oven overnight and weigh it again.
That is easy and accurate.

Good luck on your journey
Crispin

From andrew.heggie at DTN.NTL.COM Tue Jan 27 16:35:24 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:50 2004
Subject: Natural vs forced convection
In-Reply-To: <4.3.1.2.20040127093703.01f8b730@mail.ilstu.edu>
Message-ID: <TUE.27.JAN.2004.213524.0000.>

>
>At 05:41 PM 1/26/04 -0700, TBReed wrote:
>>Dear Dean and All:
>>
>>We first developed the top lit updraft gasifier stove in 1986 with forced
>>(lab air) convection. I spent the next twelve years trying to achieve good
>>air/fuel mixing with natural draft. Maybe you can solve it, but I decided
>>to get on with the job. (Sometimes the "best" 9ie cheapest is the enemy of
>>the good, more expensive but works much better).
>>
>>In 1998 I tried forced convection (~ 1 watt of blower or fan) and within a
>>week had the beginnings of our woodgas campstove.
>>

This looks like 1W(e) to cleanly produce ~3kW(t), it's a better figure
than I achieve on the larger scale, I am in the order of 90W(e) for
100kW(t) *but* my wood is 50%mc wwb.

On Tue, 27 Jan 2004 09:45:00 -0600, Paul S. Anderson wrote:

>Stovers,
>
>After meeting Tom Reed in 2001, I started work on natural convection in the
>small gasifiers. My natural-draft "Juntos stoves" have been shown and will
>be at the ETHOS meeting. I claim "reasonable success" with natural
>convection. And most recently I have been working with Agua Das on natural
>convection of his "Dasifier", again with noteworthy success.
>
>Although I am also a believer in the great power of forced convection, the
>realities of many (not all) Third World countries do justify further
>efforts on natural convection.

I'm with you Paul, just because I couldn't manage without a bit of fan
power doesn't mean its not a good goal.

In the event that fan power does have a overwhelming benefit the quest
may be for a heat engine (a chimney is a heat engine with low thermal
to motion conversion) that is acceptable. I've a hankering to try some
sort of seebeck effect device (thermopile). As you can see we only
need 1W(e) per ~3kW(t) and if the "heat engine" can dump its heat at a
higher temperature than the boiling pot there may be little loss.

AJH

From andrew.heggie at DTN.NTL.COM Tue Jan 27 16:35:45 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:50 2004
Subject: Cookstove Design- vortex
In-Reply-To: <000001c3e495$19162e90$304a31d4@toshibauser>
Message-ID: <TUE.27.JAN.2004.213545.0000.>

On Tue, 27 Jan 2004 07:50:31 +0300, Elsen Karstad wrote:

>While designing the large combustion chamber for my down-draught open-pit
>carboniser, I experimented with different air/gas mixing strategies in order
>to most efficiently burn off the volatiles- the white smoke- produced from
>the carbonisation of particulate biomass (sawdust at the time). Following
>the rule that most efficient combustion occurs when you maximise 1) dwell
>time 2) mixing and 3) temperature, I started off with a vortex but soon
>found that totally random mixing worked very much better.

Was this using only the chimney as draught?

I think I agree with you, but the cyclone effect has other benefits
and many other things are happening, not least that cold dense air
stays away from hot combining gases. I also found there was a need to
break the vortex. I know from work done at Cardiff University that the
flame must be forced to fold back on itself, both to keep temperature
up and increase mixing. I have a sneaking feeling, never having access
to the data or equipment, that in the low cv gas burner the air and
low cv gas enters the chamber at different levels and rotating counter
to each other, the turbulence then being at the shear face of the two
gases.

AJH

From hseaver at CYBERSHAMANIX.COM Tue Jan 27 17:12:36 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:30:50 2004
Subject: Natural vs forced convection
In-Reply-To: <eldd109hmcprdbuh8uvf4qiqof837tpvj6@4ax.com>
Message-ID: <TUE.27.JAN.2004.161236.0600.HSEAVER@CYBERSHAMANIX.COM>

On Tue, Jan 27, 2004 at 09:35:24PM +0000, Andrew Heggie wrote:

(much snipped)
>
> In the event that fan power does have a overwhelming benefit the quest
> may be for a heat engine (a chimney is a heat engine with low thermal
> to motion conversion) that is acceptable. I've a hankering to try some
> sort of seebeck effect device (thermopile). As you can see we only
> need 1W(e) per ~3kW(t) and if the "heat engine" can dump its heat at a
> higher temperature than the boiling pot there may be little loss.
>

I wonder if it would be possible to use a capacitor in conjuction with the
thermoelectric generator to provide a jump start to the fan, since the fan is
needed most when lighting the fire and not as much later when the fire is
blazing hot and providing the most electric power from the TEG -- which is when
the capacitor could be recharged, perhaps with a temp or voltage operated
switch.
I've read something awhile back about VW experimenting with large capacitors
in a hybrid car to provide extra acceleration without draining the batteries so
much.
The capacitor would be better than a battery since it doesn't wear out and
need replacement, or at least not nearly so fast.

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

From a31ford at INETLINK.CA Tue Jan 27 18:56:25 2004
From: a31ford at INETLINK.CA (a31ford)
Date: Tue Aug 10 18:30:50 2004
Subject: Natural vs forced convection
In-Reply-To: <20040127221236.GA15062@cybershamanix.com>
Message-ID: <TUE.27.JAN.2004.175625.0600.A31FORD@INETLINK.CA>

Harmon and all,

I don't know if anyone on the list is aware, there is an item called a
"peltiere" device, which converts heat to electricity.

Here in Canada, there are a lot of wood stoves (for heating) and most people
that I know that have a wood stove, also have at least one of these devices.
http://www.survivalunlimited.com/fans.htm or
http://www.northlineexpress.com/detail.asp?PRODUCT_ID=5CF-800

I am NOT supporting any of these links, simply listing them if,
a person wants to see what I'm talking about.

I realize that the units at these websites would not work "existing" but the
methodology is what is important.

Greg Manning
Brandon, Manitoba, Canada

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf Of Harmon Seaver
Sent: Tuesday, January 27, 2004 4:13 PM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Natural vs forced convection

On Tue, Jan 27, 2004 at 09:35:24PM +0000, Andrew Heggie wrote:

I wonder if it would be possible to use a capacitor in conjuction with
the
thermoelectric generator to provide a jump start to the fan, since the fan
is
needed most when lighting the fire and not as much later when the fire is
blazing hot and providing the most electric power from the TEG -- which is
when
the capacitor could be recharged, perhaps with a temp or voltage operated
switch.
I've read something awhile back about VW experimenting with large
capacitors
in a hybrid car to provide extra acceleration without draining the batteries
so
much.
The capacitor would be better than a battery since it doesn't wear out
and
need replacement, or at least not nearly so fast.

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

From takeda at SONIC.NET Wed Jan 28 01:02:47 2004
From: takeda at SONIC.NET (Matthew Takeda)
Date: Tue Aug 10 18:30:50 2004
Subject: Cookstove Design- vortex
In-Reply-To: <200401280500.i0S500v08347@ns1.repp.org>
Message-ID: <TUE.27.JAN.2004.220247.0800.TAKEDA@SONIC.NET>

My message seems to have elicited quite a few discussions of vortex
combustion. While that may be of interest to some, I feel that I must
clarify my original message. I am in no way trying to make the combustion
or combustion products in my stove vortical. The vortex generators I
mentioned are vanes in the secondary air input which produce mutually
interfering small vortices in order to increase turbulence in the
combustion area. I haven't implemented them yet, so I don't yet know if the
secondary air velocity is sufficient to make them worthwhile.

Matthew Takeda
the JOAT
From messinger.roth at AFRICA-ONLINE.NET Tue Jan 27 11:58:22 2004
From: messinger.roth at AFRICA-ONLINE.NET (Christa)
Date: Tue Aug 10 18:30:50 2004
Subject: Chimneys
Message-ID: <TUE.27.JAN.2004.185822.0200.MESSINGER.ROTH@AFRICAONLINE.NET>

I agree with Paul on the recommendation of gel-fuel as a starter, although I am not a great believer in gelfuel as the best way to use ethanol for cooking, but it really does a good job for lighting fires:
no risk to convert your stove into a glaring flame thrower because of the rather slow and steady burning of the jelly-like substance, no smell, no additional smoke. Easy to carry, no big risk of leakages from a container and spoiling everything else you are carrying (Who hasn't enjoyed food with a diesel or paraffin flavour so far, might not truly appreciate that advantage).
I use it to light my barbecue as well...

Christa Roth
Advisor for Food Processing and Household Energy
Integrated Food Security Programme Mulanje
P.O. Box 438, Mulanje, Malawi, Phone +265-1-466 279, Fax -466 435
----- Original Message -----
From: Paul S. Anderson
To: STOVES@LISTSERV.REPP.ORG
Sent: Tuesday, January 27, 2004 6:27 PM
Subject: Re: [STOVES] Chimneys

John,

Try this to start your stove:

Get some of that "gel-fuel" made from sugar cane and now being promoted in
Africa and elsewhere.

Paul

From pverhaart at OPTUSNET.COM.AU Wed Jan 28 01:07:09 2004
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:50 2004
Subject: NDG
In-Reply-To: <20040127141132.63994.qmail@web25103.mail.ukl.yahoo.com>
Message-ID: <WED.28.JAN.2004.160709.1000.PVERHAART@OPTUSNET.COM.AU>

Why?

Peter Verhaart

At 14:11 27/01/2004 +0000, you wrote:
> I would like to know how to calculate the
>final mass of ash in the water boiling test.
>
>=====
>krish

From pverhaart at OPTUSNET.COM.AU Wed Jan 28 01:10:56 2004
From: pverhaart at OPTUSNET.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
In-Reply-To: <026901c3e4e2$10d98ae0$6401a8c0@TOM>
Message-ID: <WED.28.JAN.2004.161056.1000.PVERHAART@OPTUSNET.COM.AU>

As far as I know a vortex is theoretically frictionless. What James P. did
was dissipate work in water. Later cynics said all it did was determine the
specific enthalpy of water to an absurd number of decimals.

Peter (see you on Saturday) Verhaart

At 07:30 27/01/2004 -0700, you wrote:
>Dear Jeff and All:
>
>I don't know if a water vortex cools or heats, but James Prescott Joule
>(1816-1889) connected a water bath with paddles to a falling weight with
>pulleys and measured the mechanical equivalent of heat - 4.186 Joules/cal.
>He thereby made himself immortal and freed us from guessing.
>
>Previously Benjamin Thompson of Woburn Mass., later Count Rumford had
>observed (but not measured accurately) this equivalence in the boring of
>cannons.
>
>We stand on the shoulders of giants.
>
>A well planned experiment can open the eyes of civilization for all times.
>"Patch on patch" thinking ultimately slows you down.
>
>Onward...
>
>TOM REED
>
>
>
>----- Original Message -----
>From: "Jeff Forssell" <jeff.forssell@CFL.SE>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Tuesday, January 27, 2004 4:50 AM
>Subject: Re: [STOVES] Vortex "believer" or experiement
>
>
> > I read something called (in swedish) "Living water" that was interesting,
>but I wasn't sure how much was true and how much was wishful thinking. At
>the end they talked about American military sneaking away with his stuff
>after WWII, but if it were all it was said to be, they wouldn't need to be
>so keen on controlling the worlds oil supply.
> >
> > There's an amusing anecdote about how Shauberger took a doubting scientist
>and waded out in a stream to measure the temperature behind a stone that
>water swirled around and, I believe, he said that it would be lower and the
>scientist said it wopuld be higher. Shauberger was according to the book
>right. When I suggested to an enthusiastic "vortexite" that we go down to
>the stream behind my house and try ourselves, he wasn't interested. A good
>story (=scientists don't know it all) is better than a good experiment for
>most people.
> >
> > (I suspect the temperatur difference would be extremely difficult to
>measure at all. I think I tried a quicky myself to make sure, but because I
>didn't expect much I didn't try very hard. Any other experience?)
> >
> >
> > > -----Original Message-----
> > > From: Harmon Seaver [mailto:hseaver@CYBERSHAMANIX.COM]
> > > Sent: Monday, January 26, 2004 11:46 PM
> > > To: STOVES@LISTSERV.REPP.ORG
> > > Subject: [STOVES] Vortex (was Rocket Science, Rocket Engineering and
> > > Cookstove Design)
> > >
> > >
> > > Have any of you read any of the works of Viktor
> > > Shauberger, more or less the
> > > father of vortex technology? Fascinating stuff. I'd think
> > > from what little I've
> > > read that it would be fairly simple to induce a vortex with
> > > the use of properly
> > > designed nozzles that wouldn't need power other than the
> > > natural draft.
> > > Do a google on "viktor schauberger" vortex air
> > >
> > >
> > > --
> > > Harmon Seaver
> > > CyberShamanix
> > > http://www.cybershamanix.com
> > >

From jeff.forssell at CFL.SE Wed Jan 28 02:20:23 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
Message-ID: <WED.28.JAN.2004.082023.0100.JEFF.FORSSELL@CFL.SE>

> ship after WWII. There is a guy selling snake-oil air conditioning
> retro-fit devices that are suppose to make money with a
> vortex.

???? Is my imagination seriously handicapped? I can't imagine what that means.

> Spinning skaters crossed with hanging pendulums or

Spinnning skaters are beautiful to watch but the phenomenon is just conservation of angular momentum. (Tho that is of course easy said than done. My skating experience is mainly stored in my "tail bone".)

> As for your stream temperature measuring non-event, remember
> that contrary
> popular opinion, much of science is founded on belief, not evidence!

I fear this is especially true in the medical business in spite of the white coats.
I would rather call the belief stuff "so-called science"

>
> Regards
> Crispin
>

From adkarve at PN2.VSNL.NET.IN Tue Jan 27 22:12:09 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:30:50 2004
Subject: Charcoal Oven
Message-ID: <WED.28.JAN.2004.084209.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Raphael,
The chimney of our own kiln is about 15 cm wide and about 180 cm tall. The entire kiln and the chimney are made from sheet metal taken from used steel barrels. Our present model takes 7 retorts, and it is meant for commercial production of charcoal. We are now working on a smaller kiln that makes use of a single 200 litre steel barrel as the oven. This unit would be used by people who want to char leaves, paper or other dry combustible household waste and convert it into briquettes for their own use. Small land holders, having just 2000 to 4000 sq.m. of land, would not find it difficult to lay their hands on such light biomass to make char briquettes for their own personal use. Our Sarai cooker requires only 100g briquettes per meal. Therefore, a family using the Sarai cooker would need only about 75 to 80 kg briquettes in a year. They can produce them by using the smaller kiln.
A.D.Karve

----- Original Message -----
From: Raphael Moras de Vasconcellos
To: A.D. Karve
Sent: Tuesday, January 27, 2004 6:53 AM
Subject: Charcoal Oven

Dear Dr Karve,

we built the charcoal oven, but a question remains: does the chimney have a specific size, diameter or shape?

Hope to send you some pictures of the oven soon.

best wishes,

Raphael Moras de Vasconcellos
raphael@bambubrasileiro.com
www.bambubrasileiro.com

From hseaver at CYBERSHAMANIX.COM Wed Jan 28 10:06:11 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:30:50 2004
Subject: Natural vs forced convection
In-Reply-To: <000801c3e531$2d09c8c0$0200a8c0@a31server>
Message-ID: <WED.28.JAN.2004.090611.0600.HSEAVER@CYBERSHAMANIX.COM>

Yes, a peltier device is a thermoelectric generator, or at least one
form. We've discussed these before, and they keep getting better and
cheaper. Since capacitors are fairly easy to make, I'd think a fairly large one
could be made in the bottom of a "tin-can" type stove fairly easily, although
I'm not sure how heat affects them. You'd probably have to have a fairly good
insulating layer between it and the actual fire pot.

There are quite a few websites with info on TEGs:
http://www.peltier-info.com/generators.html
http://www.hi-z.com/websit07.htm

And also quite a few on home-brewing capacitors, easily made from aluminum or
copper sheet with polyethelene in between.

http://deepfriedneon.com/tesla_cap1.html
http://www.hills2.u-net.com/tesla/tccap.htm

for instance. I'm not at all sure this would really work, just an idea, but it
could possibly solve the battery problem for 3rd world use, since only the TEG
and fan motor would have to be bought. Obviously very powerful capacitors can be
made at home, what I'm not sure of is whether the TEGs would provide enough
power to recharge it enough to actually run the fan before the fire got hot
enough to energize the TEG.

On Tue, Jan 27, 2004 at 05:56:25PM -0600, a31ford wrote:
> Harmon and all,
>
> I don't know if anyone on the list is aware, there is an item called a
> "peltiere" device, which converts heat to electricity.
>
> Here in Canada, there are a lot of wood stoves (for heating) and most people
> that I know that have a wood stove, also have at least one of these devices.
> http://www.survivalunlimited.com/fans.htm or
> http://www.northlineexpress.com/detail.asp?PRODUCT_ID=5CF-800
>
> I am NOT supporting any of these links, simply listing them if,
> a person wants to see what I'm talking about.
>
> I realize that the units at these websites would not work "existing" but the
> methodology is what is important.
>
> Greg Manning
> Brandon, Manitoba, Canada

From rstanley at LEGACYFOUND.ORG Wed Jan 28 08:38:06 2004
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:50 2004
Subject: Cookstove Design- vortex
Message-ID: <WED.28.JAN.2004.173806.0400.>

On the vortex issue: For the physical chemists out there: what are the effects
of a centrifuge on composition and thermal separation of presumably, pre
gasification / post pyrolosis gasses off burning biomass ?

Does the centrifugal force generated at the rotary velocities of the vortex
factor in at all ??
Strange enough a hollow core Brq will tend to generate its own vortex with no
promoting, and a stream tends not to flow straight but will curve to dump its
sediment. Something worth looking into ??

Just finished a training up in Northern Uganda where its all about basic
survival and war driven markets for alternative fuel in the face of an active
and vicious rebel gurrilla army that prevents any local activity in the field.

Investigation of the effects of vortexes--a pleasent respite !

Richard Stanley

From a31ford at INETLINK.CA Wed Jan 28 11:41:39 2004
From: a31ford at INETLINK.CA (a31ford)
Date: Tue Aug 10 18:30:50 2004
Subject: FW: [STOVES] Natural vs forced convection
Message-ID: <WED.28.JAN.2004.104139.0600.A31FORD@INETLINK.CA>

Hi Harmon & all,

I was getting at the fact that a peltier device would make a simple and cost
effective method? of forced convection of one wanted to go that route.

Can I ask why one would want a capacitor ? they are simply a storage medium.

I guess, if one stored some electricity, one could use it on a fan at the
initial stages of a burn, before the peltier device was capable of producing
enough electricity to operate the convection fan.

Is this getting to the point of a "runaway" situation of cost?

Oh well, it's a nice thought.

Greg Manning,
Brandon, Manitoba, Canada

P.S. it is VERY cold here this morning, even in the sunshine, it's still
minus 37c at 10:00am CST (non-windchill measurement),
hope the heating gasifier doesn't act up.

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf Of Harmon Seaver
Sent: Wednesday, January 28, 2004 9:06 AM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Natural vs forced convection

Yes, a peltier device is a thermoelectric generator, or at least one
form. We've discussed these before, and they keep getting better and
cheaper. Since capacitors are fairly easy to make, I'd think a fairly large
one
could be made in the bottom of a "tin-can" type stove fairly easily,
although
I'm not sure how heat affects them. You'd probably have to have a fairly
good
insulating layer between it and the actual fire pot.

There are quite a few websites with info on TEGs:
http://www.peltier-info.com/generators.html
http://www.hi-z.com/websit07.htm

And also quite a few on home-brewing capacitors, easily made from aluminum
or
copper sheet with polyethelene in between.

http://deepfriedneon.com/tesla_cap1.html
http://www.hills2.u-net.com/tesla/tccap.htm

for instance. I'm not at all sure this would really work, just an idea,
but it
could possibly solve the battery problem for 3rd world use, since only the
TEG
and fan motor would have to be bought. Obviously very powerful capacitors
can be
made at home, what I'm not sure of is whether the TEGs would provide enough
power to recharge it enough to actually run the fan before the fire got hot
enough to energize the TEG.

On Tue, Jan 27, 2004 at 05:56:25PM -0600, a31ford wrote:
> Harmon and all,
>
> I don't know if anyone on the list is aware, there is an item called a
> "peltiere" device, which converts heat to electricity.
>
> Here in Canada, there are a lot of wood stoves (for heating) and most
people
> that I know that have a wood stove, also have at least one of these
devices.
> http://www.survivalunlimited.com/fans.htm or
> http://www.northlineexpress.com/detail.asp?PRODUCT_ID=5CF-800
>
> I am NOT supporting any of these links, simply listing them if,
> a person wants to see what I'm talking about.
>
> I realize that the units at these websites would not work "existing" but
the
> methodology is what is important.
>
> Greg Manning
> Brandon, Manitoba, Canada

From Sam at V21MAIL.CO.UK Wed Jan 28 12:18:49 2004
From: Sam at V21MAIL.CO.UK (Sam)
Date: Tue Aug 10 18:30:50 2004
Subject: Shauberger
Message-ID: <WED.28.JAN.2004.171849.0000.SAM@V21MAIL.CO.UK>

Jeff Forssell says "I read something called (in swedish) "Living water" that was interesting, but I wasn't sure how much was true and how much was wishful thinking. At the end they talked about American military sneaking away with his stuff after WWII, but if it were all it was said to be, they wouldn't need to be so keen on controlling the worlds oil supply."
As far as I understand, Shaubergers apparatus was making very efficient use of the temperature differential between (in the case of post war experiments in Texas) hot air and cold groundwater, and if developed would have produced a power source which , unlike oil, could not be controlled by one country or power group.
The books (including "living Water ") by Callum Coats are probably the best source for Shauberger info.

Sam
(new to the list)

From aholland at IASTATE.EDU Wed Jan 28 12:48:50 2004
From: aholland at IASTATE.EDU (Amy Holland)
Date: Tue Aug 10 18:30:50 2004
Subject: agenda and directions for ETHOS conference
Message-ID: <WED.28.JAN.2004.114850.0600.AHOLLAND@IASTATE.EDU>

Hello,

In case we missed anyone with our first email, I am including the agenda
for the conference as well as hotel information and directions to the
hotel and the conference.

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

ETHOS 2004 Conference Schedule

Saturday, January 31, 2004

7:30 8:00 Registration coffee, tea, and sweet rolls

8:00 8:15 Welcome and Introductions Mark Bryden and Dean Still

8:15 9:15 ETHOS in the past year and Committee Reports (2 slides/committee)

9:15 10:00 Generating Global Results to Improve Stoves and Fuels

Brenda Doroski, US EPA Join with the Partnership for Clean Indoor Air to
Eliminate Smoke in Homes

Karen Westley, Shell Foundation Challenges and Lessons in
Commercialization of Improved Stoves and Fuels

Simone Lawaetz, USAID

10:00 10:15 Break coffee and tea

10:15 11:45 Improving Stove Testing and Design: Efficiency,
Effectiveness, Emissions and Safety

Dean Still and Damon Ogle

Mark Bryden Stove Safety: Some Thoughts and Proposed Guidelines

Dale Andreatta Thermal Properties of Insulative Brick

Dana Charron Nicaragua IAP Testing

Tami Bond Monitoring Stove Emissions

Dan Kammen New Boiling Water Test

11:45 1:00 Lunch (campus cafeteria cost $6.00)

1:00 2:15 Cooking Technologies: Thoughts, Ideas, and Proposed Solutions

Priya Karve - Design and Field Testing of a Compact Biogas Plant

Wilfred Pimentel Integrated Cooking

Tom Reed Gasification Stoves

Harry Stokes - The Promise of Alcohol Fuels in Africa: A New Rung on the
Energy Ladder

Rogerio de Miranda Adapting the Ecostove to the Brazilian market

Crispin Pemberton-Piggott Vesto Gasifier

2:15 3:30 Stove Design and Analysis: Talks and Panel Discussion

K. Prasad

Piet Visser

Peter Verhaart Practical applications of downdraft firing

Larry Winiarski Various Applications of the Rocket Stove Principles

3:30 3:45 Break coffee and tea

3:45 4:00 Poster Session Introductions (1 slide/3 minutes each)

4:00 5:30 Poster Session

Dar Curtis Commercialization of solar hot pots

Dale Andreatta Cookstove Pollutant Output Measurement

Paul Anderson Small Gasifier Stoves--Advances in Africa

Tom Miles The Stove List

Dean Still

Mark Bryden and Doug McCorkle Stove Design and Optimization

Margie Pinnell (not confirmed)

Lisa B?ttner

John Mitchell Partnership for Clean Indoor Air

5:30 7:30 Dinner (at the college cafeteria cost $7.50)

7:30 9:30 Slide Shows

Peter Scott Uganda, S. Africa--bread oven, new designs

Rogerio Miranda Video, Earth Report by BBC. "Environmental hazards to
children health: water/sanitation and air pollution" (the role of the
Ecostove in Nicaragua)

Larry Winiarski Coffee Husk Burner in Rwanda, Africa

Peter Verhart Down Draft Barbeque

Stuart Conway National Geographic on TWP's project to save the Magdalena
Forest in El Salvador and slides of other TWP projects in Central America

Don O?Neal

Patrick Flynn ?Insulated bricks in El Salvador Notes from the Field?

Grant Ballard-Tremeer - HEDON

Sunday, February 1, 2004

7:30 Doors open Coffee, tea, and sweet rolls

8:00 10:00 Implementing Stove Programs: Talks and Discussion Panel

A. D. Karve Case study of popularising a modern fuel through the
introduction of a modern cooking device

Don O?Neal and Richard Grinnell Mass-production of the HELPS Stove in
Guatemala

Stuart Conway Honduras Micro-Enterprise Stove Project

Omar Masera and Rodolfo D?az Jim?nez Promoting Clean Multiple-Fuel
Cooking for Improved Rural Livelihood in Latin America

Lisa B?ttner Exploring the integration of household energy into the
Alliance for Mindanao Off-grid Rural Electrification project

Jiwan Acharya ?Biogas for household energy in Nepal?

Patrick Flynn Justa Stoves in El Salvador

10:00 10:15 Break coffee and tea

10:15 11:30 Break Out Groups and Committee Meetings

12:00 1:00 Lunch (campus cafeteria cost $6.00)

1:00 1:30 Committee Reports

1:30 3:00 Outline plans for next year

3:00 5:00 Stoves Demonstration, coffee and tea

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

Hotel info: the hotel has booked more than 30 rooms in our block has
opened additional space.for us. If you are planning on staying at the
hotel and do not yet have reservations, you should make reservations
immediately.

There is a block of rooms reserved under the name of ETHOS/PCIA at:

The BEST WESTERN KIRKLAND INN
12223NE 116th Street
Kirkland, Washington 98034
(425) 822-2300

For reservations please call:

1-800-332-4200

The cost is $68 plus tax for two per night. $64 plus tax for a single.

Direction to the hotel for those driving:

NORTHBOUND
Driving North on I-405
Exit 20A (116th Street)
Right at light.
Right at Brown Bag Caf?.
Inn is located behind the Caf?.

SOUTHBOUND
Driving South on I-405
Exit 20 (124th Street)
Right at light. Immediate left at next light (120th)
Left on 116th through next light.
Right at Brown Bag Caf?.
Inn is located behind the Caf?.
------------------------------------------------------------------------------------------------------
Directions on how to get to Northwest College:

From I-405 Southbound: Take Exit 17, turn left at the light. Turn left
again at the next stoplight onto 108th Ave. N.E. and proceed for about a
half mile. Northwest College will be on your left at 5520 108th Ave. N.E.

From I-405 Northbound: Take Exit 17, turn left at the light. Turn left
again at the next light and cross over the freeway. Turn left once more
at the second stoplight onto 108th Ave. N.E. and proceed for about a
half mile. Northwest College will be on your left at 5520 108th Ave. N.E.

additional information is available at
http://www.nwcollege.edu/about/directions.html
---------------------------------------------------------------------------------------------------------

Amy

From andrew.heggie at DTN.NTL.COM Wed Jan 28 16:24:41 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:50 2004
Subject: FW: [STOVES] Natural vs forced convection
In-Reply-To: <000b01c3e5bd$9b09db80$0200a8c0@a31server>
Message-ID: <WED.28.JAN.2004.212441.0000.>

On Wed, 28 Jan 2004 10:41:39 -0600, a31ford wrote:

>Hi Harmon & all,
>
>I was getting at the fact that a peltier device would make a simple and cost
>effective method? of forced convection of one wanted to go that route.

IIRC the Peltier effect is the cooling of one junction when
electricity is passed through it, the Seebeck effect is its inverse,
the production of electricity when heat flows from a hot junction to a
cold one. The high yielding ones are based on semiconductors (I think)
however they seem to require a maximum 200C and in the order of a 100C
drop to the cool junction. So any heat passing through it is lost to
the cooking process, though OK for space heating. Metal alloy
junctions have lower effects but work at higher temperatures, so it
may be feasible to still utilise heat at the cold junction. I wonder
if anyone has a list of the peltier/seebeck effect for some common
alloys?

>Can I ask why one would want a capacitor ? they are simply a storage medium.

Harmon has covered this also.
I guess they are a storage medium with low short term losses and low
environmental impact compared with a dry cell or rechargeable cell.

>I guess, if one stored some electricity, one could use it on a fan at the
>initial stages of a burn, before the peltier device was capable of producing
>enough electricity to operate the convection fan.

IMO this start up phase should be short and could use a hand cranked
fan. This is how the Tangye coal gasified IC gensets were started.
Kevin Chisholm once posted about finding a chinese manufacturer of a
modern hand cranked fan.
>
>Is this getting to the point of a "runaway" situation of cost?

This is always the killer.

AJH

From andrew.heggie at DTN.NTL.COM Wed Jan 28 16:24:48 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:50 2004
Subject: Cookstove Design- vortex
In-Reply-To: <6.0.1.1.2.20040127215625.02798c38@pop.sonic.net>
Message-ID: <WED.28.JAN.2004.212448.0000.>

On Tue, 27 Jan 2004 22:02:47 -0800, Matthew Takeda wrote:

>My message seems to have elicited quite a few discussions of vortex
>combustion. While that may be of interest to some, I feel that I must
>clarify my original message. I am in no way trying to make the combustion
>or combustion products in my stove vortical. The vortex generators I
>mentioned are vanes in the secondary air input which produce mutually
>interfering small vortices in order to increase turbulence in the
>combustion area.

Ahh, like the vortex shedding that occurs at the tip of a wing, makes
sense but will still consume power, I imagine by making the system
look like it has a higher resistance, nice one.

Even though you were not referring to a cyclonic type system it raised
an interesting discussion.

AJH

From andrew.heggie at DTN.NTL.COM Wed Jan 28 16:50:19 2004
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:50 2004
Subject: agenda and directions for ETHOS conference
In-Reply-To: <4017F602.1060002@iastate.edu>
Message-ID: <WED.28.JAN.2004.215019.0000.>

On Wed, 28 Jan 2004 11:48:50 -0600, Amy Holland wrote:

>Hello,
>
>In case we missed anyone with our first email, I am including the agenda
>for the conference as well as hotel information and directions to the
>hotel and the conference.

I hadn't missed it but each reference to it makes me go green :-)

Have a good conference

AJH

From dstill at EPUD.NET Wed Jan 28 21:02:20 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:50 2004
Subject: FW: requesting stove contacts
Message-ID: <WED.28.JAN.2004.180220.0800.DSTILL@EPUD.NET>

Dear STOVES and ETHOS,

Ms. Fiorella Ceruti is helping to organize a conference in Santiago, Chile
from March 22 to 26 to launch the Latin American Network for School Feeding
sponsored by the World Food Program. If you are interested, please contact
her at

Fiorella.Ceruti@wfp.org

Here is her description of the activity:

"WFP is organizing a Conference in Santiago, Chile from 22 -
26 of March to launch the Latin American Network for School Feeding. One
of the topics to be developed in the series of workshops offered at this
Conference will be "environmental interventions within school feeding".
Evidently, Fuel Efficient Cooking Stoves will be the "protagonista"and for
this I would like to ask for the assistance of Aprovecho and ETHOS for two
purposes:
1. I would like to invite individuals and organizations, members of your
Centre and ETHOS network who might be interested in joining the Latin
American Network for School Feeding. Invitations to the Conference are
open to all interested parties.
2. I would like to start exploring potential names of expert(s) on fuel
efficient stoves within/for school feeding programmes in Latin America who
could be a guest speaker(s) on one of the workshops offered at the
conference. This expert should be fluent in Spanish since this will be the
official language at the conference."

WFP is a great organization. I hope that we can help them to make great
stoves! I urge all interested stovers to contact Ms. Ceruti.

Best,

Dean

From ken at BASTERFIELD.COM Thu Jan 29 14:04:10 2004
From: ken at BASTERFIELD.COM (Ken Basterfield)
Date: Tue Aug 10 18:30:50 2004
Subject: FW: [STOVES] Natural vs forced convection
In-Reply-To: <eu9g10tal1k8a9as0go3m10a1c0h38qr5p@4ax.com>
Message-ID: <THU.29.JAN.2004.190410.0000.KEN@BASTERFIELD.COM>

Can someone clarify for me please?
Is the Seebeck simply a thermocouple junction and the Peltier the
reverse effect or are they something different?
Sincerely
ken

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG] On
Behalf Of Andrew Heggie
Sent: 28 January 2004 21:25
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] FW: [STOVES] Natural vs forced convection

On Wed, 28 Jan 2004 10:41:39 -0600, a31ford wrote:

>Hi Harmon & all,
>
>I was getting at the fact that a peltier device would make a simple and
cost
>effective method? of forced convection of one wanted to go that route.

>Can I ask why one would want a capacitor ? they are simply a storage
medium.

Harmon has covered this also.
I guess they are a storage medium with low short term losses and low
environmental impact compared with a dry cell or rechargeable cell.

>I guess, if one stored some electricity, one could use it on a fan at
the
>initial stages of a burn, before the peltier device was capable of
producing
>enough electricity to operate the convection fan.

This is always the killer.

AJH

From english at KINGSTON.NET Thu Jan 29 21:14:09 2004
From: english at KINGSTON.NET (english@KINGSTON.NET)
Date: Tue Aug 10 18:30:50 2004
Subject: Vortex "believer" or experiement
Message-ID: <THU.29.JAN.2004.211409.0500.>

Hello all,
While many members of this list gather for perfect mixing at the Ethos
conference... I thought that everyone might enjoy pondering the
following; quoted without permission from the North American
Combustion Handbook, volume II
( For South America you may have to reverse the direction of swirl:)
Alex

"Swirl improves flame stability by forming toroidal recirculation zones
that recirculate heat and active chemical species to the base of the
flame and thereby broaden the range of velocity in which flame
stabilization is possible.These toroidal zones form when the swirl
number is geater than about 0.6 Swirl number ,S, is defined as the ratio
(axial flux of angular momentum)/(axial flux of the linear
momentum)x(radius) which is dimensionless. Swirl has two added
benefits: it shortens combustion time by causing high rates of
entrainment of ambient fluids, and it provides quick mixing in the
vicinity of the burner nose and along the boundaries of recirculation
zones."

From takeda at SONIC.NET Fri Jan 30 03:51:19 2004
From: takeda at SONIC.NET (Matthew Takeda)
Date: Tue Aug 10 18:30:50 2004
Subject: FW: [STOVES] Natural vs forced convection
In-Reply-To: <200401300501.i0U51rv01518@ns1.repp.org>
Message-ID: <FRI.30.JAN.2004.005119.0800.TAKEDA@SONIC.NET>

Ken Basterfield wrote:
>Can someone clarify for me please?
>Is the Seebeck simply a thermocouple junction and the Peltier the
>reverse effect or are they something different?

In 1821, Thomas Seebeck, found that an electric current would flow
continuously in a closed circuit made up of two dissimilar metals provided
that the junctions of the metals were maintained at two different
temperatures. Seebeck did not actually comprehend the scientific basis for
his discovery, however, and falsely assumed that flowing heat produced the
same effect as flowing electric current. In 1834, a French watchmaker and
part time physicist, Jean Peltier, while investigating the "Seebeck
Effect," found that there was an opposite phenomenon whereby thermal energy
could be absorbed at one dissimilar metal junction and discharged at the
other junction when an electric current flowed within the closed circuit.
Twenty years later, William Thomson (eventually known as Lord Kelvin)
issued a comprehensive explanation of the Seebeck and Peltier Effects and
described their interrelationship.

When an electric current is passed through a conductor having a temperature
gradient over its length, heat will be either absorbed by or expelled from
the conductor. Whether heat is absorbed or expelled depends upon the
direction of both the electric current and temperature gradient. This
phenomenon, known as the Thomson Effect, is of interest in respect to the
principles involved but plays a negligible role in the operation of
practical thermoelectric modules.

In the 1930's Russian scientists began studying some of the earlier
thermoelectric work in an effort to construct power generators for use at
remote locations. This Russian interest in thermoelectricity eventually
caught the attention of the rest of the world and inspired the development
of practical thermoelectric modules. Today's thermoelectric coolers make
use of modern semiconductor technology whereby doped semiconductor material
takes the place of dissimilar metals.

Matthew Takeda
the JOAT
From ventfory at IAFRICA.COM Fri Jan 30 08:29:14 2004
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:51 2004
Subject: Chimneys - cleaner top-lighting start-ups
Message-ID: <FRI.30.JAN.2004.152914.0200.VENTFORY@IAFRICA.COM>

John,

You said,

> I think that it is a case of horses for courses. Each stove and each fuel
> type will need a different configuration, with a multiple of possible
> permutations, I have tried many permutations before deciding on my final
> design.
[snipped]
> As an engineer once said to me, there are three important steps to a
successful
> design,
>
> 1 Know and understand the process.
> 2. The same as 1.
> 3 Your turn to guess ????

Thanks for the advice, and I do agree with your statement above. I am not an
engineer by trade so I have had to do a heck of a lot of research on the topic and
self-teaching to "know and understand" charcoal gasification. I still have
a lot to learn though.

You are right about each fuel type needing a different configuration.
What will happen if you were to test fire charcoal in your coal gasifier?
because when gasifying anthracite (coal) in my charcoal gasifier, I am left
with buckets of ash (I think it was 35%), which is not easy to remove
afterwards. You have obviously solved the ash problem, something I never had to contend with as charcoal only leaves approximately 10 to 40 grams of ash (2 - 10%) after the completion of the burn, depending on the fuel load.

Kind regards

Kobus

> Hi Kobus,
>
> I think that it is a case of horses for courses. Each stove and each fuel
> type will need a different configuration, with a multiple of possible
> permutations, I have tried many permutations before deciding on my final
> design.

> What works well in one stove is a failure in another, so without the
perfect
> computer model being available, it is a case of the empirical approach.
With
> luck you move in the right direction fairly quickly. The most important
> aspect is to understand the combustion qualities of the fuel and the
gasses
> needing secondary combustion, and then figuring out a way to achieve this
in
> the best manner, taking into account the constraints of the materials, and
> basic stove set up.
>
> A lot of non specific advice here, but the foundation to stove design, As
an
> engineer once said to me, there are three important steps to a successful
> design,
>
> 1 Know and understand the process.
> 2. The same as 1.
> 3 Your turn to guess ????
>
> Happy stoving,
> John.
>
> SEE BELOW.
> .
> ----- Original Message -----
> From: "Kobus" <ventfory@IAFRICA.COM>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Monday, January 26, 2004 11:48 AM
> Subject: [STOVES] Chimneys - cleaner top-lighting start-ups
>
>
> John, Crispin, Ron,
>
> John, even though we are practically neighbours, we have never
communicated.
> I think due to the fact that we stood nothing to gain from each other
apart
> from what was posted already and we are quite happy to learn from others
> across the seas.
>
> I think your stove has the potential to revolutionize indoor cooking on
the
> Reef, one day, not so far away.
>
> If I could just comment on some of your points, unfortunately not relating
> much to chimneys but more on cleaner ways of top lighting gasifiiers, but
> especially, stubborn coal and charcoal gasifiers:
>
> (snipped )
>
>
>

From ken at BASTERFIELD.COM Sat Jan 31 10:32:55 2004
From: ken at BASTERFIELD.COM (Ken Basterfield)
Date: Tue Aug 10 18:30:51 2004
Subject: FW: [STOVES] Natural vs forced convection
In-Reply-To: <6.0.1.1.2.20040130004517.02b53dd0@pop.sonic.net>
Message-ID: <SAT.31.JAN.2004.153255.0000.KEN@BASTERFIELD.COM>

Matthew,
Thank you kindly for the history
ken

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG] On
Behalf Of Matthew Takeda
Sent: 30 January 2004 08:51
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] FW: [STOVES] Natural vs forced convection

Ken Basterfield wrote:
>Can someone clarify for me please?
>Is the Seebeck simply a thermocouple junction and the Peltier the
>reverse effect or are they something different?

In 1821, Thomas Seebeck, found that an electric current would flow
continuously in a closed circuit made up of two dissimilar metals
provided
that the junctions of the metals were maintained at two different
temperatures. Seebeck did not actually comprehend the scientific basis
for
his discovery, however, and falsely assumed that flowing heat produced
the
same effect as flowing electric current. In 1834, a French watchmaker
and
part time physicist, Jean Peltier, while investigating the "Seebeck
Effect," found that there was an opposite phenomenon whereby thermal
energy
could be absorbed at one dissimilar metal junction and discharged at the
other junction when an electric current flowed within the closed
circuit.
Twenty years later, William Thomson (eventually known as Lord Kelvin)
issued a comprehensive explanation of the Seebeck and Peltier Effects
and
described their interrelationship.

When an electric current is passed through a conductor having a
temperature
gradient over its length, heat will be either absorbed by or expelled
from
the conductor. Whether heat is absorbed or expelled depends upon the
direction of both the electric current and temperature gradient. This
phenomenon, known as the Thomson Effect, is of interest in respect to
the
principles involved but plays a negligible role in the operation of
practical thermoelectric modules.

In the 1930's Russian scientists began studying some of the earlier
thermoelectric work in an effort to construct power generators for use
at
remote locations. This Russian interest in thermoelectricity eventually
caught the attention of the rest of the world and inspired the
development
of practical thermoelectric modules. Today's thermoelectric coolers make
use of modern semiconductor technology whereby doped semiconductor
material
takes the place of dissimilar metals.

Matthew Takeda
the JOAT

BioEnergy Lists: Improved Biomass Cooking Stoves

January 2004 Biomass Cooking Stoves Archive