April 2001 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 english at adan.kingston.net Sun Apr 1 08:21:08 2001
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:50 2004
Subject: Webpage update
Message-ID: <200104011219.IAA30861@adan.kingston.net>

Dear Stovers,
You can view a picture of a Griddle type stove which Aprovecho is
developing, and promoting for use in Central America, buy going to
http://www.ikweb.com/enuff/public_html/Stoves.html
and clicking the link under 'NEW'.

Alex

From ronallarson at qwest.net Mon Apr 2 21:49:22 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:50 2004
Subject: Fw: new work at ARTI
Message-ID: <036001c0bbdd$cefe1b20$ee79e13f@computer>

Stovers:

The following message seems appropriate for the full list. A.D. has
given some very helpful additional information.

A.D.

Thank you for this addition.

Below, I ask a few questions and then I repeat the questions sent to Dr.
Priya. I am sure some will be difficult, but I believe many "stoves"
members.will find it useful to hear more on your experiences with the
modified ICMIC.

----- Original Message -----
From: A.D. Karve <adkarve@pn2.vsnl.net.in>
To: Ron Larson <ronallarson@qwest.net>
Sent: Sunday, April 01, 2001 12:27 AM
Subject: Re: new work at ARTI

> Dear Ron,
> here are some additional points about the ICMIC cooker:
> 1) The name of the cooker is ICMIC and not ICMIT. ICMIC is an acronym
based
> on the initials of the organisation (or the project) that developed the
> stove, but I do not know the full form. ICMIC was released for general use
> only after extensive tests. Even the Department of Science and
> Technology, Government of India, was involved in the effort. Somehow,
ICMIC
> became popular only in Bengal. One of the reasons could be that our
> chapati, roti and bhakri require roasting, whereas ICMIC only steam-cooks
> the food. Even today, one can buy an ICMIC cooker in Calcutta.
> 2) Because a lot of research effort had already gone into the ICMIC, we
did
> not do any experiments with its dimensions. The only modification that we
> did was to separate the cooker part from the stove part, so that the
cooker
> part can be carried separately as a food carrier.

(RWL): I believe the experimental data from the ICMIC developers could
be very valuable. If you or any other list reader knows how to contact the
developing group, I believe their experimental test results could be very
helpful (I know of no other such studies).

> 3) Grandma's cooker consisted of a cylindrical vessel, called the cooker,
> with a lid on the top. Before putting it on fire, it was filled with
water,
> to the height of about 2.5 cm from the bottom. An annular stand, about 2.5
> cm high, went into the water. The pots were stacked, one on top of
another,
> within the cooker vessel, with the lowest pot resting on the stand. The
> lowest pot contained the material that took the longest time to cook.
Then
> the lid was closed and the cooker was placed on fire. The water in the
> cooker boiled and filled the cooker with hot steam. The lid was not
> steam-tight. It allowed the steam to escape without blowing the lid off.
> Normally it took about 30 minutes to cook a vegetarian meal for 6 persons
in
> this cooker (the same is true of the icmic). The housewife learnt by
> experience, how much charcoal would be required to complete the cooking.
She
> therefore charged the stove with just that amount of charcoal, and went
> about doing other household chores. She could even go out for shopping and
> return after a couple of hours. I feel that the Chinese wok also functions
> in the same manner.

(RWL): My question # 7 below asked about time - so I deduce that maybe
the charcoal is giving about a 1.7 kW output. Can you estimate how much of a
charcoal saving the ICMIC provides (because it has a second wall)?

> 4) The Bachat cooker is basically grandma's cooker turned upside down. The
> lid, which fitted on top of the older design, forms the lower shallow dish
> of Bachat cooker, to act both as carrier for water from which steam is
> generated for cooking, and also as a water seal around the rim of the
> inverted cooker pot. The pots (with the food ingredients) stand in the
dish
> in a vertical stack, and the cooker vessel is inverted over this stack.
The
> rim of the inverted cover remains covered by the water in the bottom dish.
> When the steam generates enough pressure, it must be escaping from the
water
> seal at the bottom of the Bachat cooker. Just because there is a water
seal
> at the bottom, the Bachat cooker does not become steam-tight. Remember,
the
> Bachat cooker is not a pressure cooker. Its double wall, which acts as an
> insulator, is certainly an innovation, but an electrically operated rice
> cooker, that was introduced into the Indian market almost 30 years ago,
also
> has a double wall.

(RWL): Thank you for this additional information. I encourage any of
the developers (at the University of Mumbai, I believe) to add to this -
especially on why they chose to invert the traditional approach.

The electric rice cooker that we own has only a single outer wall. It
is about a 21 cm diameter with a 19 cm rice container (which is about 10 cm
high). The wattage is 450 watts

> 5) The elaborate design and the tooling required by both the Bachat and
> ICMIC make them costly. Pressure cookers are now available at a very
> moderate price in the Indian market. However, a pressure cooker requires
> the housewife to stay near the cooker for reducing the flame (when the
steam
> pressure has built itself up), and for extinguishing the fire (when the
> cooking is over). In the non-pressurised cookers, operated on a charcoal
> fire, one could place the cooker on a stove containing a certain amount of
> charcoal and do other chores, without having to stand next to the cooker
and
> watch it carefully. The rice cooker, mentioned above, offers this
> convenience to the housewife, becasue it is electrically operated. The
> cooker turns itself off, when the cooking is over, leaving a small heating
> coil on, which keeps the food warm. That the Indian housewife is willing
to
> pay an extra price for this convenience is shown by the fact that the
> electrically operated rice cookers are quite popular in urbam households.
> However, I doubt if a housewife would go back to charcoal stoves. Both
> Bachat and ICMIC can have only a niche market, among campers and
picnickers.
> Yours Nandu
>

1. My impression of the Bachat was that it was quite a good bargain (At
about $8 for 4.5 liter size - this shows the cost of living advantages of
living in India.)
2. I like your point about convenience. (I see this as one of the main
advantages of the charcoal-making stove - as it is quite controllable and
has relatively constant output.) Our rice cooker also turns off
automatically (not sure what the sensor and logic are). It also has a
weight-sensitive switch so that the power is only on when the rice container
is inside.
3. I feel we need more explanation of your last point on niche
markets. This sounds like a statement that could be made for the US. What
percentage of Indian cooking is now done with biomass materials? Should not
the greater efficiency (the Bacharat folk claim a fuel saving of 4X) make it
attractive to a majority of Indian cooking?

<snip>

(RWL): The following are repeat - which I hope you can give some insight
into as you are able. The topic is a great one, and thanks again for the
response above.

> >
> > Q1. I hope you can report to us on the gap width that has been used
> > traditionally in the icmit - and whether you have tried any variations
on
> > that width? Any experimental data on efficiencies with different gap
> > widths?
> >
> > Q2. To compare with the Bachat principal of reducing radiative wall
> > losses, I think it would be helpful to determine the fuel savings if you
> > added one more thin (foil?) wall outside your present outermost wall.
> >
> > Q3. I hope the bachat stove developers will comment on Dr. Priya's
> last
> > sentence. In the Bachat, the outer "can" is steam tight. In the ARTI
> > version, it is more open. I see the Bachat as focusing on radiation
> losses
> > and the Icmit as focusing on convective heat transfer. I presume there
> > should be some convective impact for the Icmit even with an electric
coil
> > heat source. Any experimental data on that?
> >
> > Q4. The Icmit cookpot design should also be a big help when used
with
> a
> > charcoal-making design.. I hav found a big difference when using an
outer
> > "convective" shield and even more when adding a third for radiative
> > purposes.
> >
> > Q5. I hope you can send a photo or two to Alex. I am particularly
> what
> > distance you have from charcoal upper surface to cookpot bottom? Any
> > special considerations for air flow? Was there only a single air inlet
at
> > the bottom? Controllable? Did the thin gap serve as a chimney with
draft
> > aiding in the air flow through the briquettes?
> >
> > (RWL): Certainly 100 gms is a very fine result. Congratulations.
> What
> > would be a "normal" charcoal consumption for the same cooking task?
> >
> > Q6. Could you give a bit more on the time required for this
cooking?
> > Have you done any tests with a "haybox" approach?
> > How many stacked containers and what total weight of rice, pulses, etc
was
> > used for this much charcoal? Was this done with a single charge of
> > charcoal, or was there addition of charcoal during the cooking?
> >
> > Q7 Does the following sound right? Energy input = 0.1 kg * 30
MJ/kG
> =
> > 3 MJ = 3 MJ / (3.6 MJ/kWh) = 5/6 kWh.
> > (the same as a kW for 50 minutes? - or 2 kW for 25 minutes?)
> >

From arecop at yogya.wasantara.net.id Tue Apr 3 06:31:10 2001
From: arecop at yogya.wasantara.net.id (arecop@yogya.wasantara.net.id)
Date: Tue Aug 31 21:36:50 2004
Subject: icmic cooker
Message-ID: <127D0905BC7@yogya.wasantara.net.id>

Dear Karve and all

I am one of the workers in Glow magazine, a publication dedicated
to stove published by the Asia Regional Cookstove program.

I came across the discussion on the icmic cooker and would be
very interested to feature it in Glow magazine, especially the
improved version.

Karve, would you be able to do us a favour and do a write up on
what you have done with the cooker at ARTI? We have a
readership coverage across Asia-so spread the word.

Regards, Erwan

mic'
> cooker.
> The icmic is actually a portable metallic stove. There is a fuel
> chamber at the bottom, in which one can burn any solid fuel.
> Traditionally it is operated on coal or charcoal. On top of the fuel
> chamber, there is a cylindrical vessel. One has to pour a small
quantity
> of water at the bottom of the vessel, and then load it with cooking
> pots, stacked one on top of the other. The cylindrical vessel is
double
> walled, and the heat from the fuel chamber passes through the
gap
> between the two walls. There are holes in the outer wall near the
top of
> the cylinder for the hot air to escape. There is a close fitting lid on
> the top. The cooking chamber gets heated by the heat flowing all
around
> it, as well as by the steam generated inside. There is a handle that
> allows the stove to be moved even during operation.
> We have modified the icmic design a bit, to increase its utility.
In
> the improved version, the fuel chamber at the bottom can be
detached
> from the cylindrical 'cooker'. The design of the fuel chamber too
has
> been modified, so that it can now be used efficiently with charcoal,
> pellets, briquettes, wood, etc., either as an attachment of the
> cylindrical cooker or as a stand-alone cookstove. One can use
the
> cylindrical cooker without the fuel chamber on an electic coil or a
gas
> or kerosene stove. This is basically the bachat cooker.
> Our modified icmic works well with the char briquettes that we
make
> from dried leaves of sugarcane. We have cooked rice, pulses,
vegetables,
> as well as meat in this stove. One can easily cook for 4-5 people
using
> just 100 gm of char briquettes.
> Regards,
> Priyadarshini Karve
>

From ronallarson at qwest.net Tue Apr 3 10:22:44 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:50 2004
Subject: Fw: Household Energy Review and HEDON
Message-ID: <002901c0bc49$851eda00$ddf2b4d1@computer>

Stovers:
This message from list-member Grant Ballard-Tremmer deserves our
immediate attention.

Grant:
Congratulations on being able to get the funds from the Shell Foundation
to carry out this work. It is only through such surveys that we can learn
what is working well in different parts of the world.

Whenever you think you have enough information to give us a brief report
on results of the survey, I hope you will do so.
Best of luck.

Ron

----- Original Message -----
From: Grant Ballard-Tremeer <grant@ecoharmony.com>
To: Ron Larson <ronallarson@qwest.net>
Sent: Tuesday, April 03, 2001 1:42 AM
Subject: Household Energy Review and HEDON

> Dear Ron
>
> I hope you are well - I'm lurking in the background on the stoves list
> as you know, and from that I gather that you are as enthusiastic and
> energetic as ever!
>
<snip>

> My main reason for writing is that I'm conducting a Global Review of
> Household Energy Activities on behalf of the Shell Foundation, a new
> and major funder of Sustainable Energy initiatives worldwide and I
> have recently started up with an online survey which those active in
> Household Energy are urged to complete. Would it be possible to send
> notice of this out through the stoves list? The original notice is as
> follows below.
>
> All the best
> Grant
>
>
> ------
> "The Shell Foundation Sustainable Energy Programme has recently
> started
> a Global Review of Household Energy and would like your input.
> Participation in the review gives you a unique opportunity to bring
> the work of your organization, no matter how small or big - to the
> attention of the Foundation, and to have an impact on future funding
> opportunities. You can participate by filling in the online survey
> about your organisation and activities at
> http://ecoharmony.net/hedon/survey - it should take no more than about
> 10 or 15 minutes in total.
>
> Don't delay! I feel that this is a great opportuntity and I urge you
> to participate.
>
> Those with limited web/online access may request a text version of the
> survey through the web page, or by emailing me at
> grant@ecoharmony.com. Online submission is, however, preferred.
>
> Best wishes
> Grant Ballard-Tremeer
>
> PS. I would be grateful if you would forward this email to others
> working in household energy who may not be on the HEDON email list.
> Thanks, Grant"
>

From ronallarson at qwest.net Tue Apr 3 10:58:02 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:50 2004
Subject: Fw: Boiling Point 46
Message-ID: <003e01c0bc4e$1f2281c0$ddf2b4d1@computer>

Stovers: -- A reminder again from list-member Liz Bates that Boiling Point
can help
get stoves information to many people not on our list.

Liz: -- Thanks for everything you are doing. It is great that you are
approaching 2000 readers!!

Ron

----- Original Message -----
From: Liz Bates <lizb@itdg.org.uk>
To: <larcon@sni.net>
Sent: Tuesday, April 03, 2001 4:53 AM
Subject: Boiling Point 46

>
>
> Dear Ron
> I am currently compiling the newspages for the next edition of Boiling
> Point. Could you please publicize the next edition of Boiling Point for
me,
> so that I can promote the work people are doing through the journal. If
> anyone has any information they would like to share - projects, dates of
> meetings or workshops, publications, etc., please could you let me, Liz
> Bates, have details as soon as possible. What is needed is a short
> paragraph with a name and full contact information, as not everyone has
> email etc., so that people can find out more if they are interested.
> Remember that our readership is fast approaching 2000 addresses, so
anything
> you provide will reach a large and interested audience.
> Thank you
> Liz
>
> Liz Bates
> lizb@itdg.org.uk
> Intermediate Technology Development Group
> Schumacher Centre for Technology Development
> Bourton Hall
> Bourton On Dunsmore
> Warwickshire
> CV23 9QZ
> Tel: +44 - 01788 661100
> Fax: +44 - 01788 661101
> http://www.oneworld.org/itdg
> http:/www.itdg.org.pe
>
> Company Reg. No 871954, England
> Charity No 247257
>
>
>
>
>
> This email and any files transmitted with it are confidential and intended
> solely for the use of the individuals or entity to whom they are
addressed.
> ITDG and its subsidiaries(ITC & ITDG Publishing) cannot accept liability
or
> contractual inferences for statements which are clearly the sender's own
and
> not made on behalf of ITDG or its subsidiaries(ITC & ITDG Publishing).
>
>
>

From ronallarson at qwest.net Tue Apr 3 23:54:34 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:50 2004
Subject: solar cooking
Message-ID: <00b901c0bcba$e1e9aaa0$77f4b4d1@computer>

Stovers:
I don't believe we have ever mentioned
solar cookers on our list - as we started as a biomass-oriented list and have
never varied. My own view of the difficulties of overcoming housewife
resistance has been recently brought into question after having continuing
e-mail conversations with list member S. Narayanaswamy who was the first to give
us authoritative information on the "bachat" cookpot. I have two requests
for members:
1. Is the following book review that I have been asked
to prepare for the journal "Solar Today" (magazine of the American Solar
Energy Society) answering the questions that you would want answered when
thinking about purchasing such a book? Any editorial suggestions to
make? (I have to probably cut some words out to meet the 300 word limit
imposed by the magazine.)
2. Any comments on the solar cooking topic that we
should hear as we pursue the biomass cookstove alternative on this list?
The remainder is my draft book review. (After a
few days to make chages I will also send this to a solar cooking e-mail list for
their views as well.)
Thanks in advance. Ron

<?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" />
An Interesting New Solar Book: “Making the Most of Sunshine – a
Handbook of Solar Energy for the Common Man”. By S. Narayanaswamy

Recently, a new authoritative voice was heard in an internet (woodburning) “stoves” discussion of a
new, efficient (steam heat, double wall) Indian cook pot (the “Bachat”). The interjector, S. Narayanaswamy, also
slowly revealed his authorship of this 200-page book, which is about two-thirds
on solar cookers. The solar
knowledge, passion, and book grew
out of his now-retired career as
one of the top administrators for Kerala - a densely-populated, highly-educated region, poor state in India.

Seeing too little Indian (or any other Government) attention to the
wide-spread introduction of solar energy and especially solar cooking,
Narayanaswamy researched the solar field thoroughly (mainly through the
internet). The resulting book is,
he says. his first and last. It is
obtainable at <A
href="http://www.gobookshopping.com/">www.gobookshopping.com with a price
that is dependent on the speed with which you need it.
Narayanaswamy’s message “for the
common man” is compelling. Hundreds
of interesting tidbits are offered on every form of renewables. One can learn, for instance, about three
forms of wave energy, or the Grtzel PV cell, or the single-axis tracking
“Scheffler” concentrator being used for solar cooking (with the “Bachat”), or
green certificates. Little with a
solar label is missing from this book

But the main value for most readers will be in the two-thirds of this
200-page book dealing with solar cooking.
More than a dozen different solar cooker designs are presented – mostly
without critique. As this author
practices what he preaches, most interesting are his sections on the best
day-to-day uses of any solar cooker.
His administrative and policy background makes Naryanaswamy’s final
chapter, “Promotion of Solar Cookers,” compelling reading for anyone introducing
solar hardware anywhere, but especially in developing countries.

The negatives? First, too
many typos – but these are obviously due to the printer, not the author. Second, too few references - but there
are plenty of leads and especially for web sites (ex:
http://solarcooking.org).
This reviewer came away with a new
appreciation of the potential for solar cooking - and now ready on the type of
cooker and cooking to build and try first.

{Review by Ron Larson, Golden CO
ronallarson@qwest.net}
ew months
ago, when we had the first discussions on "stoves" about the

From Auke.Koopmans at fao.org Tue Apr 3 23:57:42 2001
From: Auke.Koopmans at fao.org (Koopmans, Auke (FAORAP))
Date: Tue Aug 31 21:36:50 2004
Subject: Smokey photo?
Message-ID: <3F078B30BD9FD21190830090273A70A901DD49A6@rapexch1.fao.org>

I should have pictures of smokey kitchens which I took in Nepal some time
ago. In fact the kitchens were sometimes so dark (no windows nor
ventilation) and smokey that I had to call out to my colleague so I could
turn the camera to where her voice came from. For a sample see
http://www.rwedp.org go to Newsletter (sidebar on the left) and select WEN
12.1 Wood Energy, Women and Health. On page 4 top left you will find one of
the pictures. Let me know if you need something like this.

Regards,

Auke Koopmans

> -----Original Message-----
> From: Jonathan Rouse [SMTP:J.R.Rouse@lboro.ac.uk]
> Sent: Friday, March 30, 2001 5:36 PM
> To: stoves@crest.org
> Subject: Smokey photo?
>
> Hi,
>
> I am looking for a photograph for the front cover of a publication on
> indoor air pollution (mostly relating to poor stoves, fuels and house
> design). Does anyone have any striking images which may be
> suitable and which they would be willing to share? I have lots of
> photos of stoves but none are very smokey (I have obviously
> imporved them all too much) ....
>
> Cheers
>
> Jon
> ---------
> Jonathan Rouse
> Research Assistant
> Water, Engineering and Development Centre
> www.lboro.ac.uk/wedc/
>
> The Stoves List is Sponsored by
> Pyromid Inc. http://www.pyromid.net
> Stoves Webpage, Charcoal, Activated Carbon
> http://www.ikweb.com/enuff/public_html/Stoves.html
> http://www.crest.org/renewables/biomass-info/carbon.shtml
> Other Sponsors, Archive and Information
> http://www.nrel.gov/bioam/
> http://solstice.crest.org/renewables/stoves-list-archive/
> http://www.crest.org/renewables/biomass-info/
> For information about CHAMBERS STOVES

From dstill at epud.net Wed Apr 4 03:35:53 2001
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:36:51 2004
Subject: solar cooking
Message-ID: <001601c1d76c$ff6c1e00$06acefd8@default>

Dear Ron,

I think that it would be very interesting to hear from our
STOVES list about solar cooking. Certainly cooking with the sun is theoretically
very attractive: no pollution, doesn't add to entropy, decreases fuel use, etc.
We are all probably aware of the history of solar uses and solar cooking going
back to Mouchot in the 1870's, probably even earlier. "A Golden
Thread" by Butti and Perlin is such a great read, as interesting as
"Direct Use of the Sun's Energy" by Daniels. I have often thought that
if Schumacher was the Merlin behind the AT movement, then Telkes and Daniels
were king and queen.

We use two really big Telkes designed solar cookers at
Aprovecho to cook a large proportion of food during the brief but hot Oregon
summer. The cookers intercept more than 30 square feet of sunlight reflected
down into a black box, well insulated and tight, aimed at the sun. The glass is
36" by 36" surrounded by reflectors at 120 degrees to the glass. These
cookers easily reach 400 degrees F during the middle of the day. Chickens brown,
french fries jump and bubble in oil. On a hot day we receive around 250 Btu's
per hour in each square foot of sunlight. Repeated experiments have shown that
between 25 to 35% of the total energy gets into the pot to cook food. So the big
Telkes generates a little less heat than is released from one pound of dry wood
burned over the time period of an hour. Something like 2,000 Btu's make it into
the pot to cook food. We find that thermal loads of more than 12 pounds start to
slow the cooking process compared to a wood stove. 24 pounds of pot, water, food
will more or less double the normal cooking time in our huge solar oven. Light
weight pots help. Very important to cut down as much as possible thermal mass in
the oven itself. Direct use ain't nearly as concentrated as the stored solar
energy in wood.

The Telkes design does not need to be reoriented
very often, maybe once in an hour. My opinion is that solar cookers need to be
powerful to win affection. Leaky, low powered cookers like the Solar Box Cooker
could not cook enough beans for a family in Baja California at 23 degrees N. in
a day of cooking. On the other hand, and this is contradictory, our experiments
with the CooKit panel cooker, with SHE, Int., showed both 3 cups of millet
and 3 cups of pinto beans cooking to completion in three hours in Oregon, 44
degrees N. I was impressed by the CooKit concept. We changed it to be waterproof
and added a glass, air tight enclosure around the pot which made something that
we found surprisingly serviceable. Very simple, cheap, great for rice,
etc. It's just a panel reflector surrounding a pot on bottom and three
sides. Costs less than 10 dollars complete.

My field experience with introducing solar cooking is limited
to Baja California, Mexico. Cardboard cookers became garbage in a week after a
heavy dew. Plywood models along the same lines were rejected as way too slow,
under powered. A big Telkes amazed everyone and was used frequently. It cost
fifty dollars though.

A truncated reflective cone at 45 degrees to the center line
(aimed at the sun) focuses to a line in the middle of the cone. Mouchot invented
this for the French army in the 1870's. My Mexican buddies liked it for making
coffee which we all drank as a social institution. ( Home roasted from green
beans and as soul satisfying as a sunrise.) A cone three feet in diameter would
boil a pint of water in 11 minutes which made a couple of cups. Much easier and
cleaner than starting the wood stove.

We continue to mess around with solar cooking every summer,
trying to find that magic design that will be attractive to folks. So far the
Telkes, waterproofed CooKit and Mouchot come closest. Each does particular
cooking tasks well. In a perfect world perhaps with a great, non polluting wood
stove would come a retained heat cooker ( Haybox) and a solar oven for baking
and a paraboliic or conical reflector for boiling water...Whole package might
cost $100 which is dinner and a movie for some folks.

Best,

Dean Still
Aprovecho
<BLOCKQUOTE
style="BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">

From ronallarson at qwest.net Wed Apr 4 13:28:56 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Fw: solar cooking
Message-ID: <001501c0bd2c$a9f52580$587ae13f@computer>

Stovers:
Dale (a list member) sent this
privately - but I think it is worth sharing as his web site (see below) is very
interesting. I will be writing Dale separately as I don't yet believe we
have enough support for talkng about solar cooking on this list unless it is
something already being done by our list members (as in this case).
Also there is a good solar cooking list
already.

Dale:
Thanks for your message.
Hope you don't mind my sending this on. Your web site is quite fascinating
- and it is clear you are doing some very interesting development work on your
own - of all types. I wish I had your talents tor putting things
together.

Ron

----- Original Message -----
From: <A
href="mailto:costich@pacifier.com" title=costich@pacifier.com>Dale Costich

To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Sent: Wednesday, April 04, 2001 7:07 AM
Subject: Re: solar cooking

Ron: I am glad to offer my expertise in solar
concentration cookery...it works great see:
<A
href="http://costich.tripod.com">http://costich.tripod.com
pictures of my 12 foot parabolic robotized
concentrator describe a successful method that will cook anything worth eating,
all from the comfort of your easy chair.
Dale Costich
Brush Prairie, Wa
<BLOCKQUOTE dir=ltr
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Ron
Larson
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Sent: Tuesday, April 03, 2001 8:53
PM
Subject: solar cooking

Stovers:
I don't believe we have ever mentioned
solar cookers on our list - as we started as a biomass-oriented list and have
never varied. My own view of the difficulties of overcoming housewife
resistance has been recently brought into question after having continuing
e-mail conversations with list member S. Narayanaswamy who was the first to
give us authoritative information on the "bachat" cookpot. I have two
requests for members:
1. Is the following book review that I have been
asked to prepare for the journal "Solar Today" (magazine of the American
Solar Energy Society) answering the questions that you would want answered
when thinking about purchasing such a book? Any editorial suggestions to
make? (I have to probably cut some words out to meet the 300 word limit
imposed by the magazine.)
2. Any comments on the solar cooking topic that we
should hear as we pursue the biomass cookstove alternative on this list?
The remainder is my draft book review. (After a
few days to make chages I will also send this to a solar cooking e-mail list
for their views as well.)
Thanks in advance. Ron

An Interesting New Solar Book: “Making the Most of Sunshine – a
Handbook of Solar Energy for the Common Man”. By S. Narayanaswamy

Recently, a new authoritative voice was heard in an internet (woodburning) “stoves” discussion of a
new, efficient (steam heat, double wall) Indian cook pot (the “Bachat”). The interjector, S. Narayanaswamy,
also slowly revealed his authorship of this 200-page book, which is about
two-thirds on solar cookers. The
solar knowledge, passion, and
book grew out of his
now-retired career as one of the top administrators for Kerala - a
densely-populated,
highly-educated region,
poor state in India.

Seeing too little Indian (or any other Government) attention to the
wide-spread introduction of solar energy and especially solar cooking,
Narayanaswamy researched the solar field thoroughly (mainly through the
internet). The resulting book is,
he says. his first and last. It
is obtainable at <A
href="http://www.gobookshopping.com/">www.gobookshopping.com with a price
that is dependent on the speed with which you need it.
Narayanaswamy’s message “for the
common man” is compelling.
Hundreds of interesting tidbits are offered on every form of
renewables. One can learn, for
instance, about three forms of wave energy, or the Grtzel PV cell, or the
single-axis tracking “Scheffler” concentrator being used for solar cooking
(with the “Bachat”), or green certificates. Little with a solar label is missing
from this book

But the main value for most readers will be in the two-thirds of this
200-page book dealing with solar cooking. More than a dozen different solar
cooker designs are presented – mostly without critique. As this author practices what he
preaches, most interesting are his sections on the best day-to-day uses of any
solar cooker. His administrative
and policy background makes Naryanaswamy’s final chapter, “Promotion of Solar
Cookers,” compelling reading for anyone introducing solar hardware anywhere,
but especially in developing countries.

The negatives? First, too
many typos – but these are obviously due to the printer, not the author. Second, too few references - but there
are plenty of leads and especially for web sites (ex:
http://solarcooking.org).
This reviewer came away with a
new appreciation of the potential for solar cooking - and now ready on the
type of cooker and cooking to build and try first.

{Review by Ron Larson, Golden CO
ronallarson@qwest.net}
ew months
ago, when we had the first discussions on "stoves" about the

From arecop at yogya.wasantara.net.id Wed Apr 4 21:50:13 2001
From: arecop at yogya.wasantara.net.id (arecop@yogya.wasantara.net.id)
Date: Tue Aug 31 21:36:51 2004
Subject: Call for conribution to Glow
Message-ID: <1521709091D@yogya.wasantara.net.id>

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From jpmanley at midcoast.com Thu Apr 5 07:02:09 2001
From: jpmanley at midcoast.com (Pat Manley)
Date: Tue Aug 31 21:36:51 2004
Subject: Masons on a Mission
Message-ID: <200104051101.HAA28738@dns.midcoast.com>

Hello everyone
We have returned from our mission, and my website has been updated with
results and new pictures. Please check it out if so inclined.
http://www.midcoast.com/masonsonamission
su amigo...Pat

<previous message...>
Hello stovers
On Thursday, Feb 1st, 2001, Tom Clarke (Guatemala Stove Project) and myself
(Patrick Manley- Masons on a Mission) will be flying to Guatemala for over a
month to lead over a dozen volunteer masons and helpers from the US and
Canada, and 3 or 4 local Maya masons to replace over 100 three stone fires
in the small village of el Rincon (near Xela) with hand built brick and
block cookstoves. This is a small village, and we may be able to build a new
cookstove in every dwelling in the village.
All the materials for this project will be bought in Guatemala with money
that Tom and I have raised over the past year.
Tom and I went to the relocated village of Santa Catarina Ixtahuacan last
year and managed to build 26 cookstoves.
Fellow Canadian stover Norbert Senf is one of our 6 volunteer masons this year.

If anyone is interested in learning more about our project, please visit my
web site at http://www.midcoast.com/masonsonamission

If anyone wants to be copied in on progress reports e-mailed out over the
course of the project, just reply to me and I will add you to my list.
Su Amigo
Pat Manley
J Patrick Manley
Brick Stove Works
15 Nelson Ridge South
Washington Maine 04574
207 845 2440

From Reedtb2 at cs.com Fri Apr 6 16:37:50 2001
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:51 2004
Subject: solar cooking
Message-ID: <a0.1289ebd0.27ff8281@cs.com>

(Don't forget that using biomass for cooking is "solar" in the larger sense.)

I have been aware of direct solar cooking for 30 years and have always viewed
it as interesting, but generally impractical for most people. For the
majority of us 6 billion people the sun shines only part of the time and we
tend to eat breakfast early in the day and dinner late.

Furthermore, the sun is a moving source, adding to its complications.

So, maybe direct solar cooking is good for some ... but a really good
woodgas stove with all the features of a propane stove will be generally more
applicable.

Thanks for the update...

TOM REED

Dear Ron,

I think that it would be very interesting to hear from our STOVES list
about solar cooking. Certainly cooking with the sun is theoretically very
attractive: no pollution, doesn't add to entropy, decreases fuel use, etc.
We are all probably aware of the history of solar uses and solar cooking
going back to Mouchot in the 1870's, probably even earlier. "A Golden
Thread" by Butti and Perlin is such a great read, as interesting as "Direct
Use of the Sun's Energy" by Daniels. I have often thought that if
Schumacher was the Merlin behind the AT movement, then Telkes and Daniels
were king and queen.

We use two really big Telkes designed solar cookers at Aprovecho to cook a
large proportion of food during the brief but hot Oregon summer. The
cookers intercept more than 30 square feet of sunlight reflected down into
a black box, well insulated and tight, aimed at the sun. The glass is 36"
by 36" surrounded by reflectors at 120 degrees to the glass. These cookers
easily reach 400 degrees F during the middle of the day. Chickens brown,
french fries jump and bubble in oil. On a hot day we receive around 250
Btu's per hour in each square foot of sunlight. Repeated experiments have
shown that between 25 to 35% of the total energy gets into the pot to cook
food. So the big Telkes generates a little less heat than is released from
one pound of dry wood burned over the time period of an hour. Something
like 2,000 Btu's make it into the pot to cook food. We find that thermal
loads of more than 12 pounds start to slow the cooking process compared to
a wood stove. 24 pounds of pot, water, food will more or less double the
normal cooking time in our huge solar oven. Light weight pots help. Very
important to cut down as much as possible thermal mass in the oven itself.
Direct use ain't nearly as concentrated as the stored solar energy in wood.

The Telkes design does not need to be reoriented very often, maybe once in
an hour. My opinion is that solar cookers need to be powerful to win
affection. Leaky, low powered cookers like the Solar Box Cooker could not
cook enough beans for a family in Baja California at 23 degrees N. in a day
of cooking. On the other hand, and this is contradictory, our experiments
with the CooKit panel cooker, with SHE, Int., showed both 3 cups of millet
and 3 cups of pinto beans cooking to completion in three hours in Oregon,
44 degrees N. I was impressed by the CooKit concept. We changed it to be
waterproof and added a glass, air tight enclosure around the pot which made
something that we found surprisingly serviceable. Very simple, cheap, great
for rice, etc. It's just a panel reflector surrounding a pot on bottom and
three sides. Costs less than 10 dollars complete.

My field experience with introducing solar cooking is limited to Baja
California, Mexico. Cardboard cookers became garbage in a week after a
heavy dew. Plywood models along the same lines were rejected as way too
slow, under powered. A big Telkes amazed everyone and was used frequently.
It cost fifty dollars though.

A truncated reflective cone at 45 degrees to the center line (aimed at the
sun) focuses to a line in the middle of the cone. Mouchot invented this for
the French army in the 1870's. My Mexican buddies liked it for making
coffee which we all drank as a social institution. ( Home roasted from
green beans and as soul satisfying as a sunrise.) A cone three feet in
diameter would boil a pint of water in 11 minutes which made a couple of
cups. Much easier and cleaner than starting the wood stove.

We continue to mess around with solar cooking every summer, trying to find
that magic design that will be attractive to folks. So far the Telkes,
waterproofed CooKit and Mouchot come closest. Each does particular cooking
tasks well. In a perfect world perhaps with a great, non polluting wood
stove would come a retained heat cooker ( Haybox) and a solar oven for
baking and a paraboliic or conical reflector for boiling water...Whole
package might cost $100 which is dinner and a movie for some folks.

Best,

Dean Still
Aprovecho

From ronallarson at qwest.net Sat Apr 7 12:38:12 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Masons on a Mission
In-Reply-To: <200104051101.HAA28738@dns.midcoast.com>
Message-ID: <02ec01c0bf81$03eca260$dc79e13f@computer>

Pat - Thanks for this update report. You and other members of
"masonsonmission" are to be greatly commended for doing this work. I didn't
pay enough attention to your February notice of leaving. When you get up
another trip, I'd like to be informed and would like to try to go along.

Since I'll bet that you (or Norbert Senf and/or others) will have some
valuable guidance to pass on to others, let me try some questions (which
came to me from a quick review of your web sites)

1. Could you break down the $150 stove cost into its different major parts.
I am particularly interested in the metal plate (thickness and dimensions)
the costs of concrete blocks (sizes, number, and transport cost), and the
stove pipe (guage, diameter, length). How much of the total was for
transport?

2. The $150 is cheap by US standards, but probably pretty expensive there.
Do you see any way to cut costs? Could the villagers make their own brick
that might work?

3. Is there any evidence on commercial extensions of your work by local
masons in other areas or villages? Is the cost perceived as being
worthwhile?

4. Can you describe the uniformity of heating of the metal plate? I
thought I saw both solid plates and plates with four circular cutouts. Did
you offer alternatives?

5. Any comments on whether wood use was more or less over the 3-stone
approach?

6. On this list, we don't say much about stove space heating, so your
comments on how this stove operated as a night-time heater would be helpful
to some. Were you striving for a lot of mass? Was there any insulation
used? Did people start sleeping closer to the stove?

7. Any way of estimating the completeness of combustion? (exhaust color
from the stove pipe?) Could the air flow be cut to zero?

8. Any other important messages for this list? When do you go again?

Thanks again for sending your report - I think many of us would like to hear
more.

Ron

----- Original Message -----
From: Pat Manley <jpmanley@midcoast.com>
To: <stoves@crest.org>
Sent: Thursday, April 05, 2001 5:01 AM
Subject: Masons on a Mission

> Hello everyone
> We have returned from our mission, and my website has been updated with
> results and new pictures. Please check it out if so inclined.
> http://www.midcoast.com/masonsonamission
> su amigo...Pat
>
>
>
> <previous message...>
> Hello stovers
> On Thursday, Feb 1st, 2001, Tom Clarke (Guatemala Stove Project) and
myself
> (Patrick Manley- Masons on a Mission) will be flying to Guatemala for over
a
> month to lead over a dozen volunteer masons and helpers from the US and
> Canada, and 3 or 4 local Maya masons to replace over 100 three stone fires
> in the small village of el Rincon (near Xela) with hand built brick and
> block cookstoves. This is a small village, and we may be able to build a
new
> cookstove in every dwelling in the village.
> All the materials for this project will be bought in Guatemala with money
> that Tom and I have raised over the past year.
> Tom and I went to the relocated village of Santa Catarina Ixtahuacan last
> year and managed to build 26 cookstoves.
> Fellow Canadian stover Norbert Senf is one of our 6 volunteer masons this
year.
>
> If anyone is interested in learning more about our project, please visit
my
> web site at http://www.midcoast.com/masonsonamission
>
> If anyone wants to be copied in on progress reports e-mailed out over the
> course of the project, just reply to me and I will add you to my list.
> Su Amigo
> Pat Manley
> J Patrick Manley
> Brick Stove Works
> 15 Nelson Ridge South
> Washington Maine 04574
> 207 845 2440
>
>
> The Stoves List is Sponsored by
> Pyromid Inc. http://www.pyromid.net
> Stoves Webpage, Charcoal, Activated Carbon
> http://www.ikweb.com/enuff/public_html/Stoves.html
> http://www.crest.org/renewables/biomass-info/carbon.shtml
> Other Sponsors, Archive and Information
> http://www.nrel.gov/bioam/
> http://solstice.crest.org/renewables/stoves-list-archive/
> http://www.crest.org/renewables/biomass-info/
> For information about CHAMBERS STOVES
>
>

From tmiles at teleport.com Sat Apr 7 16:54:32 2001
From: tmiles at teleport.com (Tom Miles)
Date: Tue Aug 31 21:36:51 2004
Subject: Asia Regional Cookstoves Program (ARECOP)
Message-ID: <4.3.2.7.2.20010406182709.022aec40@mail.teleport.com>

I've added a few links to the cookstoves section of the Bioenergy reference
page at:

http://solstice.crest.org/renewables/biomass-info/

New additions include:

Masons on a Mission and Guatemala Stove Project
ARECOP (Asia Regional Cookstoves Program), RWEP (Regional Wood Energy
Program in Asia)
Aprovecho Stoves page

I learn something new every time I look at the Stoves web page at:

http://www.ikweb.com/enuff/public_html/Stoves.html

regards,

Tom Miles

Thomas R Miles tmiles@trmiles.com
T R Miles, TCI Tel 503-292-0107
1470 SW Woodward Way Fax 503-292-2919
Portland, OR 97225 USA

From ronallarson at qwest.net Sun Apr 8 23:54:33 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Commenting on Cleveland and biomass/solar
Message-ID: <001801c0c0a8$bb37aa00$48afa0d8@computer>

Jerry:

Several thoughts come to
mind. There is a different <A
href="http://www.crest.org">http://www.crest.org list called
"digestion" that you should look at. China, India and Nepal all are doing
good work in the residential cooking areas, with stove burners that are slightly
modified to run better on the methane output from small digesters. My
understanding is that the "Indian" approach,which used to feature a floating
metal inverted "can" for gas capture is being dropped in favor of a "Chinese"
approach with a more or less spherical fixed underground cavity and gas capture
by forcing effluent out past a water seal. We have stayed away from this
subject on this list because of the presence of the other "sister" list.
It seems to work well only when there are a minimum number of livestock to
provide the input dung.

We have had some discussion on this list also, and a
paper at the Pune conference, on first converting the methane to methanol, with
much easier storeability and transportability, as well as a very lovely
controllable flame for cooking. It looks likely that better economics for
some time will result from methanol produced in large quantities at sites where
there is excess natural gas, with transport by boat to ports and then inland -
much as kerosene is traded. These proponents also recognize it can be done
in-country with large biomass-to-methane convertors. You might want to
look up this in our archives.

There are others of us on this
list interested in gasifying biomass for cooking through pyrolysis. The
gas is much like methane (and contains some) in burning characteristics.
Charcoal may or may not be a by-product. There is a lot of past material
on this topic in our archives. The advantage here is a very low cost means
of getting many of the characteristics we need in a stove besides low cost
- low emissions, controllable flame, high efficiency, etc. Let us know if
this is of interest instead.

Hope this provides useful leads. Good luck. Ron 

----- Original Message -----
From: <A
href="mailto:midwestmonolithic@hotmail.com"
title=midwestmonolithic@hotmail.com>Jerry Cleveland
To: <A href="mailto:Stoves@crest.org"
title=Stoves@crest.org>Stoves@crest.org
Sent: Friday, April 06, 2001 8:04 PM
Subject: biomass/solar

Stovers, Has anyone been working with biofuel in the form of
methane? I read about home built methane digestors built in India years
ago but was never able to get detailed instructions on how to do it though I am
still interested. Is the technologhy to complicated or expensive for you
purposes? If anyone has more information I would be happy to receive
it. I know they wee once featured in Mothers Earth News.
Thanks, Jerry

Get your FREE download of MSN Explorer at <A
href="http://explorer.msn.com">http://explorer.msn.com
The Stoves List is Sponsored by Pyromid Inc. http://www.pyromid.net
Stoves Webpage, Charcoal, Activated Carbon
http://www.ikweb.com/enuff/public_html/Stoves.html
http://www.crest.org/renewables/biomass-info/carbon.shtml Other Sponsors,
Archive and Information http://www.nrel.gov/bioam/
http://solstice.crest.org/renewables/stoves-list-archive/
http://www.crest.org/renewables/biomass-info/ For information about CHAMBERS
STOVES

From ronallarson at qwest.net Mon Apr 9 00:51:30 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Keith Addison and Journey to Forever
In-Reply-To: <F13Cekp8tg1zSarY6FD00002358@hotmail.com>
Message-ID: <007b01c0c0b0$ad3ce480$48afa0d8@computer>

Keith
You said about methane digesters:

<snip>
> You should find all you need here (Big page):
>
> http://www.webconx.com/methane.htm
> Methane Digesters
>
> Best
>
> Keith Addison
> Journey to Forever
> Handmade Projects
> Tokyo
> http://journeytoforever.org/

That really was a "BIG" page - lots of great leads on biodigestion. Thanks.

But I am also interested in hearing more about "Journey to Forever" - which
also was an interesting site. Can you tell us more about the trip to South
Africa, whether you personally are going to be on it, and you and the
organization's work on stoves. Does this trip have a connection to the
"Rio+10" climate change conference being in South Africa? Thanks in advance
for answers.

Ron

From keith at journeytoforever.org Mon Apr 9 21:43:58 2001
From: keith at journeytoforever.org (Keith Addison)
Date: Tue Aug 31 21:36:51 2004
Subject: Keith Addison and Journey to Forever
In-Reply-To: <F13Cekp8tg1zSarY6FD00002358@hotmail.com>
Message-ID: <v04210104b6f8058809ce@[61.121.38.68]>

"Ron Larson" <ronallarson@qwest.net> wrote:

>Keith
> You said about methane digesters:
>
> <snip>
> > You should find all you need here (Big page):
> >
> > http://www.webconx.com/methane.htm
> > Methane Digesters
> >
> > Best
> >
> > Keith Addison
> > Journey to Forever
> > Handmade Projects
> > Tokyo
> > http://journeytoforever.org/
>
>
>That really was a "BIG" page - lots of great leads on biodigestion. Thanks.

Hello Ron

You're welcome. Steve's site has excellent resources on bioenergy and
biofuels, and much besides, you can spend a lot of time there!

>But I am also interested in hearing more about "Journey to Forever" - which
>also was an interesting site. Can you tell us more about the trip to South
>Africa, whether you personally are going to be on it, and you and the
>organization's work on stoves. Does this trip have a connection to the
>"Rio+10" climate change conference being in South Africa? Thanks in advance
>for answers.

Thanks for your interest. I can't tell you much more about the trip
than is on the site (but that's quite a lot!). Yes, I'll be going. It
doesn't have a direct connection with Rio+10, though we do plan to
get involved in that in some way or another. We'll still be far away
by then - I think this journey will take 3-4 years, or maybe 10 or
20! Or forever. But the Internet's a big part of the project, so it
won't much matter where we are.

We're in Japan now, both as the final stage of project preparation
and the first part of the journey, though not at all a typical part.
We'll be here for a lot longer than other places, for one thing, we
have a lot of work to do here. I doubt we'll be leaving before the
end of the year.

Re stoves, there's a stoves page on our site, maybe you saw it:
http://journeytoforever.org/at_woodfire.html

But we're not stoves experts at all. We're hoping to develop working
relationships with some of the organisations and people referred to
on that page (who all seem to be members of this great list) when it
comes to finding good solutions at village level where appropriate
during our journey.

However, we have been working with stoves, but as one of our
education projects, and in fact it's ground to a halt because we're
baffled! I was about to ask the list for help. We've built four
smallish IDD stoves so far, each one better than the last, but still
far from good enough, and we don't know how to proceed.

Here's what it's about. Japan makes itself unpopular worldwide by
throwing away 130 million pairs of disposable wooden chopsticks per
DAY!!! - made, of course, with great waste, out of other people's
forests, not their own (which are in rather good condition). Some
countries are being seriously deforested because of Japan's throwaway
chopsticks. The Japanese are not unaware of the appallingness of it,
but not a lot gets done, beyond tokenism. At perhaps its worst is
this disposable chopsticks wrapper in front of me, from one of the
ubiquitous convenience stores, labelled "Ecology Earth Effort", with
a rationale that's quite beyond me.

It's something that needs a good push to get some action going with a
bit of will behind it. Maybe it doesn't need very much of a push,
it's sort of ready to happen. Some of the schools are aware enough -
some don't use them, some even collect them and do things with them -
one turns them into paper and makes postcards out of them. A local
organic farmer also collects them, grinds them up in his shredder and
puts them in his compost pile. And so on.

We think burning them is a good idea, in an IDD cookstove. Preferably
it should be an IDD cookstove that a school class could make in a few
hours, preferably out of cans (millions of waste cans here, they get
recycled but it's a good part of the lesson), and that would then
work without fail (also without gassing everybody) while cooking the
rice for one's school lunch. It's not that long ago that everyone
still cooked with charcoal, so to get TWO cooks out of a handful of
chopsticks, one with the chopsticks, the other with the charcoal, has
a lot of lesson potential. When you add in the lesson about how such
stoves can improve lives in the Third World, and the conditions
there, along with the obvious lesson of the disposable chopsticks
themselves, well, we think it's good stuff to learn. Not just for
Japan, but this is the place to start. (We'll do a publicity number
with it too, we're quite good at that.)

Anyway, between the idea and the reality... If I took some pictures
of our latest prototype stove and put them on our website somewhere,
explaining the problems we're having, do you think the list might be
able to help us get it right? If the advice turns out to be: "It's
misbegotten junk! Throw it away! Start again and do it right!" - we'd
very happily do just that!

Our education pages, by the way, are getting quite popular, with
about 8,000 visits a month now, growing quite fast. Still, that's the
least popular major section of our site and it's due for a push - we
were hoping to use a perfected stove as part of the push!

Well, Ron, you did ask - sorry if you got a bit more than you
bargained for! :-)

Incidentally, they still cook with charcoal here, but now it's more
of a luxury, for "special" dishes. However, there's an excellent
traditional charcoal cookstove that's still available, very
interesting, which I'll tell the list more about once I've made some
more inquiries.

Thanks again, and best wishes

Keith Addison
Journey to Forever
Handmade Projects
Tokyo
http://journeytoforever.org/

>Ron
>
>
>The Stoves List is Sponsored by
>Pyromid Inc. http://www.pyromid.net
>Stoves Webpage, Charcoal, Activated Carbon
>http://www.ikweb.com/enuff/public_html/Stoves.html
>http://www.crest.org/renewables/biomass-info/carbon.shtml
>Other Sponsors, Archive and Information
>http://www.nrel.gov/bioam/
>http://solstice.crest.org/renewables/stoves-list-archive/
>http://www.crest.org/renewables/biomass-info/
>For information about CHAMBERS STOVES

From ronallarson at qwest.net Wed Apr 11 16:24:50 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Fw: Bachat Cooker & ICMIC compared
Message-ID: <03fe01c0c2c5$39953700$9d7ee13f@computer>

Stovers: The following useful comparison of two interesting cookpots has
come in today from one of the developers (in Bombay) of the Bachat stove,
several descriptions of
which have appeared on this list. Note also the serch near the end for a
particular type of cook stove.

Shirish: Thank you very much for sending this message. I shall send
separately several messages from the two Dr. Karves in Pune. One of these
seems to describe a second shield outside the ICMIC - which I believe is
intended to add some insulation but has the more important (I guess) value
of increasing the convective heat transfer to the inner pot. Your
description does not seem to contain this added element.

After you have read these earlier communications, I hope you will write
again to let us know if there are any remaining misconceptions.

On behalf of all "stoves" list members, let me again congratulate you on
making such a large improvement in cooking efficiency.

With respect to the current work you describe below on coupling the
Bachat with a batch-loaded, constant-output, self-extinguishing,
biomass-fired cookstove, I hope that you will look closely at the
charcoal-making stove, about which this list has had extensive discussion.
It would seem to me to come closer than anything else I have seen to what
you want, although I have seen no version which is self-extinguishing.
Rather the cook would have to watch for the end of pyrolysis and then set
the Bachat into a "hay-box" and take steps to "suffocate" the remaining
charcoal. If one chooses to consume the charcoal, there has to be a
significant change of air flow as the charcoal will begin being consumed
from the bottom up.

Do any of those on the list who have tried the charcoal making approach
(top-down pyrolysis with separate primary and secondary air supplies) think
they know how to either change the air flow automatically to consume the
charcoal efficiently and cleanly, or know of a way to "snuff" the charcoal
production at the right time? I don't. But perhaps rural cook stove
operators will not mind too much making this one time intervention - in
order to save and later sell the manufacutred charcoal.
Although they cannot operate as with electricity (or gas or liquid fuels),
there could still be a substantial time saving.

Alternatively, perhaps there are others on the list who can suggest a good
biomass approach as is desired.

Should you find such a stove as you are looking for, all of us on this
list will be most anxious to hear about it.

(the remainder of this message is as received - and is identical to the
attachment.)

To: S Narayanaswamy ,<snswamy@md2.vsnl.net.in>; Ron Larson
<ronallarson@qwest.net>
Sent: Wednesday, April 11, 2001 2:02 AM
Subject: Bachat Cooker & ICMIC compared

> 11 April
>
> Dear Ron, SN,
>
> I understand there has been some discussion on the 'Stoves' site regarding
> Bachat and how it resembles the ICMIC cooker. I have not seen the
exchange,
> not being a member of the site. But we have prepared a note comparing the
> two cookers, and I thought you might be interested in seeing it. It's
> attached.
>
> Regards,
>
> Shirish
>

9 April 2001

Bachat and ICMIC Cookers compared

There is a superficial resemblance between the two cookers. If you are not
much concerned with fuel saving, then it does not much matter which one you
use. Both are steam cookers. Both cook several items simultaneously. Both
call for slow cooking, as a result of which many foods taste better. And
neither needs any attention during cooking. The Western "crock-pot" is also
similar, in that it is a slow steam cooker, needing no attention, which
produces enhanced flavours.

However, if fuel saving is a central concern, as it was during the
development of Bachat, then there are significant and critical differences
between Bachat and ICMIC. These differences must be respected, and
implemented, in order to obtain the maximum fuel saving.

Despite their apparent similarities, Bachat is not a derivative of the ICMIC
cooker. As explained on the website www.bachatcooker.com, Bachat started out
as a solar cooker. At some point, for reasons of marketing strategy, it was
decided to develop the solar cooker in two parts: (i) a cooking pot that
would save fuel on a normal flame, and (ii) a blurred-focus concentrator
requiring infrequent adjustments that would be used with the same cooking
pot. Research focussing exclusively on the cooking pot began 4 years ago. We
were looking for:

(a) the specific factors in the pot that made for fuel efficiency
(b) a simple design that could be easily manufactured, without sophisticated
or centralised manufacturing capability, and
(c) the lowest possible unit cost.

At the end of the research work, the following 4 factors emerged as the most
important. It is not that there are no others. For example, pressurising the
cooking containers does help save fuel. It was discarded because the extra
cost and complexity of manufacture was not justified by the fuel savings
obtained. The most significant 4 factors are the following. Each of these in
isolation saves about 30% of the fuel:

(1) Use a small flame in relation to the base diameter of the cooker, so no
heat is lost up the sides.
(2) Switch off early, but do not open the cooker. Food continues to cook in
its own heat, as it does in a haybox cooker. A critical detail here is that
the water in the base MUST be in contact with the bottom cooking vessel when
cooking starts, but MUST NOT be in contact when the flame is switched off.
This is required so that the bottom vessel starts heating immediately, but
after the flame has been switched off, does not cool too fast-the air gap
below the bottom vessel at the end of heating is an important insulator.
(ICMIC does not require this air gap).
(3) Insulate the cooker. This can be done in a variety of ways. We found the
cheapest was an extra metal "top hat" over the lot, with insulation provided
by the air gap between the "top hat" and the steaming chamber. It was also
sturdy, flame-proof and easy to clean. Ideally, to avoid heat losses by
convection in the air gap, the air gap between the two hats should be not
much more than 5 or 6mm.
(4) Stack the cooking vessels fairly tightly over each other. This produces
the fuel-saving benefits of multi-stage evaporation.

Of these 4 principles, ICMIC makes use only of the last. As a result, ICMIC
does save fuel. According to our results, we would guess about 30%, because
of multi-stage evaporation. But even here, we would like to draw attention
to an apparently small detail. In Bachat, the cooking vessels fit fairly
snugly over the portion of the base that holds the water. There are steam
vents, which function also to allow condensing water above to trickle back
into the bottom, but these are limited. In an earlier version of Bachat, the
steam vents were too few. As a result, if the flame below was too strong,
the steam velocity through the vents was so forceful that condensing water
could not get back into the base, which dried out, resulting in the food not
being cooked. We had to revise the design to provide more steam vents. But
these are still minimal, so as to ensure that the effect of multi-stage
evaporation is maximised.

In ICMIC the cooking containers sit in a base of water which is open to the
annular space around the cooking containers. Steam moves freely around the
cooking containers, so the effect of side heating should be stronger, and
the effect of multi-stage evaporation weaker than in Bachat. The fuel
savings on account of multi-stage evaporation should therefore be less in
ICMIC than in Bachat. But we must emphasise that we have conducted no tests
on the ICMIC cooker (we have not been able to procure one, they are not
readily available in Bombay), and what is said above is based on the
theoretical considerations we have developed.

Nevertheless, the more important point is that multi-stage evaporation is
only one of 4 equally important fuel-saving principles discovered in our
research. To get the fullest possible fuel saving, of up to 75%, the
critical details set out in (1), (2) and (3) above must also be implemented
and incorporated in the finished design.

The final product, Bachat, happens to resemble ICMIC in its configuration,
except for one further detail: the ICMIC cooker consists of a deep container
that forms the base and is the steaming chamber. The stacked cooking vessels
are held in a cradle and are lowered into this chamber, which is then closed
with a tight-fitting shallow lid. In Bachat, this configuration is inverted:
the base is shallow, and the lid is a tall, inverted "top hat". For small
sized cookers, purely in terms of handling both configurations work equally
well, ICMIC or Bachat. For larger capacities, as might be used for community
cooking, where cooking containers need to total 20 or 50 litres in volume,
we believe the Bachat configuration will be more practical. The relatively
light hats can be more easily manipulated than a set of heavily loaded
cooking containers that have to be lifted and then lowered into a deep pot.

Further Development:

The development of a companion wood-burning stove for Bachat is now our
current preoccupation. Ideally, we need something that delivers a flame (or
heat) over a 7 cm diameter area. The stove once charged and set alight
should need no further attention. The fuel should burn out and the device in
effect self-extinguish after burning for the desired time. In developing
this stove we are working with Prof H S Mukunda (mukunda@cgpl.iisc.ernet.in)
and Dr S Dasappa (dasappa@cgpl.iisc.ernet.in) of the Indian Institute of
Science, Bangalore, as well as Prof P D Grover (pdg@del2.vsnl.net.in),
former Dean of IIT Delhi.

Work is also continuing on community cooking. With Bachat it may be possible
to use a domestic-sized wood stove, without modification, for a 20-litre
community cooker. This should produce worthwhile fuel savings in community
cooking.

If you have any questions, please email queries@bachatcooker.com.

G K Bhide
Prof J B Joshi
Kishore V Mariwala
Dr Aniruddha B Pandit
Shirish B Patel
R S Shah
Dr Rekha Singhal

Bachat&ICMICcompared080401.doc

The Stoves List is Sponsored by
Pyromid Inc. http://www.pyromid.net
Stoves Webpage, Charcoal, Activated Carbon
http://www.ikweb.com/enuff/public_html/Stoves.html
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From ronallarson at qwest.net Wed Apr 11 16:31:38 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Keith Addison and Journey to Forever
In-Reply-To: <F13Cekp8tg1zSarY6FD00002358@hotmail.com>
Message-ID: <046001c0c2c6$2a0bbf60$9d7ee13f@computer>

Hello Keith
Stovers:
This is my followup to a response a few days ago from Keith Anderson who
had given some good guidance on biodigestion and then I had some followup
questions based on having visited his web site, which is also mentioned
below.

This asks or answers a few more questions where appropriate:

<SNIP>
(Keith)

> We're in Japan now, both as the final stage of project preparation
> and the first part of the journey, though not at all a typical part.
> We'll be here for a lot longer than other places, for one thing, we
> have a lot of work to do here. I doubt we'll be leaving before the
> end of the year.
>
> Re stoves, there's a stoves page on our site, maybe you saw it:
> http://journeytoforever.org/at_woodfire.html
>

(RWL): Yes, I saw it and hope others on our list may let you now of
something special they are doing that should place them on your list as
well. I joined one group because you had it listed.

> But we're not stoves experts at all. We're hoping to develop working
> relationships with some of the organisations and people referred to
> on that page (who all seem to be members of this great list) when it
> comes to finding good solutions at village level where appropriate
> during our journey.
>
(RWL): I think you are the only list member writing from Japan. As you
run into others please ask them to join (Japan or whereever)

> However, we have been working with stoves, but as one of our
> education projects, and in fact it's ground to a halt because we're
> baffled! I was about to ask the list for help. We've built four
> smallish IDD stoves so far, each one better than the last, but still
> far from good enough, and we don't know how to proceed.
>
(RWL): Please define IDD.

> Here's what it's about. Japan makes itself unpopular worldwide by
> throwing away 130 million pairs of disposable wooden chopsticks per
> DAY!!! - made, of course, with great waste, out of other people's
> forests, not their own (which are in rather good condition). Some
> countries are being seriously deforested because of Japan's throwaway
> chopsticks. The Japanese are not unaware of the appallingness of it,
> but not a lot gets done, beyond tokenism. At perhaps its worst is
> this disposable chopsticks wrapper in front of me, from one of the
> ubiquitous convenience stores, labelled "Ecology Earth Effort", with
> a rationale that's quite beyond me.
>
> It's something that needs a good push to get some action going with a
> bit of will behind it. Maybe it doesn't need very much of a push,
> it's sort of ready to happen. Some of the schools are aware enough -
> some don't use them, some even collect them and do things with them -
> one turns them into paper and makes postcards out of them. A local
> organic farmer also collects them, grinds them up in his shredder and
> puts them in his compost pile. And so on.
>
> We think burning them is a good idea, in an IDD cookstove. Preferably
> it should be an IDD cookstove that a school class could make in a few
> hours, preferably out of cans (millions of waste cans here, they get
> recycled but it's a good part of the lesson), and that would then
> work without fail (also without gassing everybody) while cooking the
> rice for one's school lunch. It's not that long ago that everyone
> still cooked with charcoal, so to get TWO cooks out of a handful of
> chopsticks, one with the chopsticks, the other with the charcoal, has
> a lot of lesson potential. When you add in the lesson about how such
> stoves can improve lives in the Third World, and the conditions
> there, along with the obvious lesson of the disposable chopsticks
> themselves, well, we think it's good stuff to learn. Not just for
> Japan, but this is the place to start. (We'll do a publicity number
> with it too, we're quite good at that.)
>
(RWL): The person on our list with the greatest skill now in making
beautiful small charcoal making stoves out of waste cans is Richard Boyt.
As a retired potter, he probably has a special affinity also to Japan.
(Richard - I hope you will enter this discussion on this novel use of waste
chopsticks.)
Many of us will try to help with anything having to do with
charcoal-making stoves. Give us the questions.

> Anyway, between the idea and the reality... If I took some pictures
> of our latest prototype stove and put them on our website somewhere,
> explaining the problems we're having, do you think the list might be
> able to help us get it right? If the advice turns out to be: "It's
> misbegotten junk! Throw it away! Start again and do it right!" - we'd
> very happily do just that!
>
(RWL) I suggest sending the the photos directly to Alex
English.<english@adan.kingston.net>
who seems to be able to handle most everything.

> Our education pages, by the way, are getting quite popular, with
> about 8,000 visits a month now, growing quite fast. Still, that's the
> least popular major section of our site and it's due for a push - we
> were hoping to use a perfected stove as part of the push!
>
> Well, Ron, you did ask - sorry if you got a bit more than you
> bargained for! :-)
>
> Incidentally, they still cook with charcoal here, but now it's more
> of a luxury, for "special" dishes. However, there's an excellent
> traditional charcoal cookstove that's still available, very
> interesting, which I'll tell the list more about once I've made some
> more inquiries.
>
(RWL): We will look forward to it. And you didn't overload us.

> Thanks again, and best wishes
>
> Keith Addison
> Journey to Forever
> Handmade Projects
> Tokyo
> http://journeytoforever.org/
>
>
>

Best of luck on this incredible journey - still hope to join you on some
part of it..

Ron

From ronallarson at qwest.net Wed Apr 11 16:34:21 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Forwarding Narayanaswamy on solar and biomass cookers
Message-ID: <046501c0c2c6$8b25d740$9d7ee13f@computer>

Stovers:
The following message was sent privately to me but as we have had some
other communication today mentioning solar cookers, the following also seems
worth sending on (in part), and I do not believe that "SN" (the Inidan
author of the book whose review I sent a while ago) will mind my doing so

At the end, he describes some experience with the sawdust stove. I have
separately noted to hime that this stove has been mentioned several times in
this list and was the subject of Dr. P. Karve's Master's thesis.

Ron

SN: Thank you for sending this on. I trust you will not mind my
sending it further. I have one order for your book - a person who read my
copy, was very enthusiastic about it., and wants his own copy.

Ron

----- Original Message -----
From: S N <snswamy2@yahoo.com>
To: Ron Larson <ronallarson@qwest.net>
Sent: Sunday, April 08, 2001 12:39 PM
Subject: Your two letters

> Dear Ron,
>
> Thanks for your two letters.
>
> I cannot disagree with Tom Reed and Dean Still. If
> solar cookers were that smart they would already have
> been widely used. The proof of the pudding is in the
> eating. For those who " tend to eat breakfast early in
> the day and dinner late" - with no lunch I presume at
> home - the solar cookers wouldn't work. Solar cooking
> may not be found by every user to be very convenient
> or useful. But people should know about the potential
> of the solar cooker and not dismiss it out of hand. It
> will be nice if they can give it a fair and patient
> trial.
>
> Given the laws of physics which we know pretty well I
> really cannot think of major breakthrough in a solar
> cooking device, which will still remain cheap, and
> will have overcome all its handicaps of slow cooking
> and uncertain weather. I believe that the Best is the
> enemy of the Good, so let us use the solar cooker, in
> the form it is available today, if the individual user
> finds it reasonably OK. Equally important as the
> financial saving is the convenience of use - the
> 'load-and-forget' quality.
>
> We are bargain hunting all the time. Even a 15%
> discount at a sale entices us. Why shouldn't a solar
> cooker entice us when its cost spread over its
> lifetime is ridiculously low but the problem here is
> the upfront payment requirement of $40.
>
> No device is without its good and bad points. When the
> solar cooker can't be used because of bad weather it
> looms large as a major frailty. But the fossil fuels
> which are very convenient for quick cooking are not
> problem free. They pose environmental problems and
> global warming but this demerit is not seen as a
> user's problem - it is seen as someone else's
> problem. In India it is common sight to see households
> and eating establishments throw their rubbish on the
> public road. This remains the mentality even in
> developed countries though not practised in such a
> crude fashion.
>
> My purpose in writing the book was only to put down my
> experience so that people may know about the solar
> cooker's versatility and not to trod on someone else's
> sensibilities. Just before we left India we could not
> run down the kitchen inventories to zero and so we
> placed all the leftovers (grains,cereals, etc) in
> bottles in the solar cooker and heated them to
> appropriate levels. I am very hopeful they will
> survive our 6 month absence in the hot humid weather
> of Kerala - just one of the uses of the solar
> cooker.
>
> Now coming to your design ideas. Richard Wareham's
> Sunstove cooker is really a tetradedron type (somewhat
> asymmetrical) of cooker. Please see
> http://www.sungravity.com/molded.html. It sits on one
> side (not base) of the tetrahedron and the opposite
> side (on the top) is the glazing. It is very light to
> carry (only 2-3 kg as against the 12-14 kg of the
> conventional box cooker). This is made in Kolkata in
> India and I had a few pieces airlifted to Trivandrum
> and it seems to work pretty well.

<snip>
>
> Biomass is an important energy source in Kerala.
> Because of good rains most of Kerala is heavily wooded
> and even in the plains there is plenty of coconut
> trees. The fronds and other droppings from the coconut
> trees come very handy for the poor people. This is one
> reason why the poor in Kerala are not hit hard by the
> fuel problem. Even as late as 1966 when I was the
> chief govt. functionary in a district (the state of
> Kerala is divided into a dozen or so districts) I was
> using a biomass stove using saw dust. LPG had not
> entered Kerala then. One had to use either a kerosene
> stove or a firewood stove. The saw dust stove is a
> simple steel cylinder - say 12 inches tall and 9 in.
> diameter, open top, closed bottom, with a 3 or 4 in.
> hole toward the bottom on one side to let air in -
> into which saw dust is densely packed from the top
> after placing a 3in. dia.cylindrical wooden rod
> vertically down the centre of the cylinder. The wooden
> rod is gently withdrawn and friction holds the saw
> dust in place. The saw dust is gently taken out at the
> side hole at the bottom till the scooped out hole
> connects with the vertical central hole which ensures
> air passage. The saw dust is set fire to at the bottom
> hole and it burns at an even slow pace. But nowadays
> there is a shortage of not only saw dust but also
> firewood what with population also increasing.
> Government schools and Govt.-aided schools in Kerala
> provide free lunch up to class VII. While govt.
> provides the rice and lentil (whole green moong dal)
> cooking is to be arranged by the parent-teacher
> association with the help of only a small grant from
> the govt. I learnt only the other day that in some of
> the hill districts in Kerala they had to abandon the
> lunch programme because of shortage of wood fuel. I
> should imagine that in the other states of India which
> have much less rain availability of firewood should be
> a real problem. The World Bank aided scheme of Social
> Forestry under which all unused government lands
> including lands abutting highways are planted with
> fast growing speices like eucalyptus which can provide
> some wood material for the population is one measure
> to alleviate this problem but it is not adequate to
> meet the needs.
>
> I would indeed like to learn more about your biomass
> devices in due course.
>
> Shall write later.
>
> Narayanaswamy
>

From ronallarson at qwest.net Thu Apr 12 10:18:53 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Request for design assistance on a specific sized charcoal making stove
Message-ID: <073b01c0c35b$2fad4a20$9d7ee13f@computer>

Stovers -
As part of an off-line
dialog on the Bachat and ICMIC Indian steam cookers, I promised to ask
those on the list to report on any of their past, present, or future efforts to
achieve a small biomass-based charcoal-making cookstove with the properties that
the Bachat cooker people would like - 0.5 kW, 0.5 kWh, and a flame diameter of
about 7 cm (or less?).

We have been using 18 megajoules
per kG and with 3.6 megajoules per kWh, this says we get about 5kWh per kg - or
that about 100 gms of biomass is needed for this job. With a charcoal
maker giving 25% charcoal by weight (with a charcoal yield of about 30 MJ/kg or
about 40% by energy content), we should start with about 40% more weight - about
140 grams (or 150 to allow for some
unknown inefficiencies?)

Anyone able to report on such an
effort? I am sure that the Bachat stove developers would be delighted to
hear of any relatively constant output wood-burning stove that worked with
anything near 100 - 150 grams.

As an aside, my past expereince
with these stoves says that one can use a cap with the desired exit flame
diameter - and that the fuel diameter can be different from 7 cm - although this might not be too far off.
I am guessing that we need a fuel height that is twice as large - but haven't
had the time to think this through. One hour of pyrolysis time was
possible with a larger diameter fuel container of 15 cm diameter, but this
had much greater output than 0.5 kW.

Anyone?

Thanks in advance -
Ron

From Reedtb2 at cs.com Fri Apr 13 07:59:41 2001
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:51 2004
Subject: Keith Addison and Journey to Forever
Message-ID: <67.12878563.28084397@cs.com>

Dear Stovers:

Ron asked...
<<
(RWL): Please define IDD. >>

I don't think Keith answered Ron. I presume IDD stands for the inverted
downdraft gasifier. This was my name, descriptive of what I developed from
the conventional downdraft gasifier. The conventional downdraft gasifier
uses the internal combustion engine to draw gas DOWN through first the
biomass, burning the volatiles and then through the resulting charcoal,
cracking some more tars and gasifying much of the charcoal.

While it is convenient to draw the gas down and feed fuel on top, the hot gas
flows in opposition to natural convection which prefers hot gases to go up.
For this reason it is not possible to have a very slow rate of conversion,
since natural convection overcomes slow forced downward conrvection.

Facing this problem in 1985, I developed the "Inverted Downdraft Gasifier",
IDD, in which the biomass is lit on the top and works down through the fuel
mass, generating gases which rise by natural convection to the top where they
are burned.

The advantage is that the gas is generated very simply, suitable for stoves.

One characteristic is that because of the very slow pyolysis, the charoal
yield is quite high, typically 15-25% - and advantage if you want charcoal, a
disadvantage if you want to convert all the fuel to gas.

The disadvantage is that if you wish to extent the process it is necessary to
auger fuel in at the bottom of the pile rather than pouring it top. However,
since cooking is a batch process, the size of the container controls the
energy output and cooking rate.

~~~~~~~~~~~
The name may be too complicated for those not acquainted with gasification,
and so Ron calls it a "charcoal making stove" or a "top burning stove"
process.

IDD implies an understanding of why it works. Thanks Keith....

TOM REED

From ronallarson at qwest.net Fri Apr 13 23:48:33 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Fw: Bachat Stove by Shirish
Message-ID: <01d101c0c495$8d3e1080$6ff2b4d1@computer>

Stovers:

The following indicates that the Bachat developers are employing a
charcoal-making stove approach much like we have been discussing on this
list. I hope others will join in on the issues being discussed below, to
help speed up their development work.

Shirish:
Glad that we/you are making progress fast here. I am taking the liberty
of adding notes as I pass this on to the list.

Ron

----- Original Message -----
From: Shirish B. Patel <shirish@spacpl.com>
To: Ron Larson <ronallarson@qwest.net>
Cc: Aniruddha B Pandit <abp@udct.ernet.in>; J B Joshi <jbj@udct.ernet.in>;
Rekha Singhal <rekha@foodbio.udct.ernet.in>; R S Shah
<jaijui@bom8.vsnl.net.in>; G K Bhide <agb@vsnl.com>; kishore Mariwala
<kishorem@bom3.vsnl.net.in>
Sent: Friday, April 13, 2001 4:20 AM
Subject: Bachat Stove

> 13 April
> Dear Ron,
>
> Many thanks indeed for your comments, and for putting us on the Stoves
list
> (free!)

(RWL): Should have said this is free to all. Please let me know if I
should add more of your associates (same for anyone reading this.). Also
feel free to leave me out of the loop as you send messages to the list (You
run the great risk of me adding too much to your own comments)

> Let me describe the design we have from Prof HSMukunda. It burns
> wood chips top-down, air supply from below, with an auxiliary air supply
> from an annular chamber that surrounds the fuel chamber and has small
holes
> between the two chambers near the top.

(RWL): Not quite sure of this geometry. I presume that "auxiliary"
means secondary air (by far the largest amount) - and you are achieving some
added efficiency by preheating this air. Several of us have done this as
well - but also have used downward flowing air past the (upper) combustion
region (as opposed to the much cooler fuel region).

I have found that "chips" provide a considerable resistance to primary
air flow. I have mostly used vertically-oriented sticks (small branches -
maybe these can be thought of as long pellets)

> At the end, you are left with a
> useful amount of charcoal. The wood burns with a little smoke and soot,
> unless you attach a small blower to increase the air flow through the
> annular chamber. If you do that, the smoke miraculously disappears. I only
> saw the first quarter of an hour of the stove working, not what happens
when
> it finishes.
>
(RWL): It sounds like the combustion chamber might be a tad short
(Increasing the chimney height will bring more primary and secondary air).
Can you describe the geometry more completely (height and diameter of both
the fuel chamber and the combustion zone)?

> Prof HSM had a small battery-operated fan to do the blowing, but we feel
the
> cost of the battery cell is unacceptable, especially if it needs
replacement
> almost every day.
>
. (RWL): One argument is that a PV powered recharge system could be
affordable. One hundred or more recharges should be achievable and the
amount of PV is not excessive. But I am somewhat in agreement and have been
trying to achieve natural convection myself. The two ways to achieve this
are either taller chimneys or a "looser" fuel.

> What we had in mind for further development was the following:
>
> (1) Reduce the diameter of the fuel chamber to reduce the heat output. It
> should also be easier to light if the area is smaller. We found lighting
> from the top not as simple or quick as lighting from below, so reducing
the
> area to be lit should help. Incidentally (I may be wrong of course) I am
not
> enthusiastic about a larger diameter stove with a lid that has a small
> opening. Even if the lid is internally reflective, it will heat up, and
> there will be radiation losses from the lid and to that extent fuel
wasted.
>
(RWL): The heat output is also a strong function of the primary air
flow. I don't know what control you have assumed, but this is a most
important variable. We have tried many different mechanisms - my favorite
has become several ceramic plugs partially inserted in round holes (below
the fuel). I agree that it is moe difficult to light than when lighting
from the bottom, but I did become able to always light with a single match -
after some experimentation. Having dry fuel is very important.

Re lighting, I suppose we have all eventually found some satisfactory
approach. I have used long pine needles (Ponderosa pine). Today, in a
totally different venue, I learned from a "survival" specialist of his
preference for using vaseline-soaked cotton balls - with what he termed a
"metal-match". I think he also used a term like "pyrophoric-metal" - which
was claimed to be a mixture of 14 different materials. When "scraped" with
a "smoothed" hack saw blade, one gets a really impressive array of sparks -
much bigger than I have found with other "sparkers". My "instructor" easily
ignited a vaseline-imbedded cotton ball with these sparks. It looks like
it is potentially cheaper than matches, but the cost of the "metal match"
will have to be lower than I paid!! Does anyone have other experience with
this product?

Re the smaller opening, my experience has not been so negative - I
guess we/you need to do some more detailed experiments. In any case, as you
have said, it is not clear that it is necessary to have the smaller diameter
for your needs - a 7 cm diameter can might be about right..

> (2) Make the fuel chamber as tall as necessary to ensure burning for one
> hour. If the volume of the food to be cooked is reduced, fill the fuel
> chamber less than full.

(RWL): Yes.

>
> (3) Try natural draft for the annular chamber. To get a good draft, the
> annular space should not be too wide (our Dr Pandit is going to calculate
> the optimal width). On the other hand, we do need an adequate air supply.
In
> this, reducing the inner diameter (as we need to do to get a small flame
> size) helps: with a constant annular gap, the ratio of annular area to
core
> area increases as core diameter reduces.
>
(RWL): I am afraid I don't quite understand the problem. My experience
is that the draft for the secondary air supply is no problem at all with a
tall enough combustion chamber. (That is there is almost always a strong
negative pressure pushing the secondary air in. But there is certainly a
need for a wind shield. The flames are quite sensitive to a mild wind
without some wind shield. I suggest that a downward flowing source will
do more to improve efficiency than where I perceive this annular region to
be located. Again, it will help to have a more complete despcription.

Such drawings largely have appeared on a web site maintained by Alex
English <english@adan.kingston.net>. Just send him an attachment - he will
advise if he can't make sense of what you send.

> (4) If natural draft doesn't work--and we dearly hope it will--try a
> mechanical system, clockwork or a falling weight, to drive a small fan.
All
> mechanical systems are susceptible to breakdowns, so we will try hard to
> avoid them.
>
(RWL): Sounds like a good approach. I am not aware of anyone using
other than electrical powr, but perhaps someone can provide something to
speed your development process. I have heard of people using large old
inner tubes which were pumped full in advance of need. Can't remember where
I saw it mentioned, though.

> We have conducted no trials ourselves as yet: we are waiting for a
> fabricator to produce a version of Prof Mukunda's stove for us to try out.
> But have I understood you correctly, that is, after the wood has burnt
down,
> and charcoal remains, there is a sudden increase in the amount of smoke?
> Pardon my ignorance, but for me this is new terrain--some of my
colleagues,
> Prof Joshi and Dr Pandit may be more knowledgeable, but I find them
> unreachable for the next few days.
>
(RWL): Yes. The problem is that the initial pyrolysis phase only needs
a very small amount of primary air. After the pyrolysis phase is complete,
or as it nears completion, then there is not enough (now need both primary
and secondary) air for the clean combustion of the charcoal. The air inlet
being at the bottom is not where you would prefer it - the hot gases rising
are now not combustible.

> I would not worry about the required dryness of the fuel, as long as the
> required moisture level can be achieved by ordinary sun drying of wood
> chips. If drying the wood chips calls for something more than simple
> exposure to the sun for a day or two or three, then we need to think about
> it more carefully.

(RWL): Yes, I think this is normally enough. But one should not plan
on using the usual experience of fuel drying sufficiency.
>
> I think you are absolutely right, a charcoal producing stove is the way to
> go, because of the income-earning possibilities it offers. Would the same
> stove also burn charcoal, or does that call for a different design? If you
> can send us descriptions of stoves that produce charcoal as a byproduct we
> would be very pleased: we can decide then what to try out, and what kinds
of
> trials to run.
>
(RWL): I believe it is necessary to have a different stove for the
appropriate combustion of the charcoal. The plots I have seen for the
charcoal combustion show a temperature too low at the pot level for doing
much useful. The charcoal is too far away from the cookpot.

But I suppose that there could be some sort of auger or lift system, so
I don't want to say there is no hope. But the usual production of charcoal
is so poor that I hope charcoal production in this manner can be
encouraged - especially as the income can go to the cook. I believe the
cost of the stove should be recoverable within months from the value of the
charcoal.

(RWL): I will send somthing, but you will also find useful
descriptions on Alex's web site:
http://www.ikweb.com/enuff/public_html/Stoves.html

I hope that Alex, Tom Reed, Tom Duke, Elsen Karstad, Richard Boyt, and
several others with experience in this area will also chime in with their
own ideas.

> With Prof PDGrover in Delhi I saw wood-burning charcoal-producing stoves
of
> a much larger size, of a kind that might be used for community cooking or
> hot water. The charcoal was then blended with clay and made into
cylindrical
> briquettes with numerous through holes parallel to the axis of the
cylinder,
> of a size suited to a domestic stove. These burn beautifully. They were
too
> large in diameter for our needs, but Prof PDG saw no difficulty in making
> them of as small a diameter as desired, to deliver the reduced output we
> want.
>
> Regards,
>
> Shirish
>

(RWL): Yes, I have seen several excellent larger charcoal making stoves
designed by Professor Grover. I am not aware of whether he has tried the
design we have been discussing. Professor Grover has contributed much
knowledge to the world of charcoal making.

Although the charcoal should provide a good fuel, I don't believe it
will be possible to use charcoal to get the desired constant output with the
small diameter flame you desire. I gather that you have come to the same
conclusion. As an aside, I can say it has always amazed me that the
charcoal-making stove can provide such constant output over time. I am
equally amazed that the downward propagating pyrolysis front only very
rarely propagates non-uniformly. That is, all parts of the pyrolysis front
seem to arrive at the bottom at about the same time. I cannot point at a
physical law that suggests why this should be so.

The type of briquetting you are describing might also be possible to use
for the input to the charcoal-making stove - maybe starting with
agricultural waste. I believe the key will be finding a way of both getting
the required air flow through the fuel and preventing a cave in after the
pyrolysis has occured (which doesn't occur with charcoal from "twigs"
because there is sufficient structural integrity after pyrolysis)

Best of luck.

Ron

From ronallarson at qwest.net Sat Apr 14 23:34:52 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Forwarding AD Karve on the "Vivek" "sawdust" stove
Message-ID: <00d301c0c55c$eced1f40$e57ce13f@computer>

stovers:

The following is a useful
possible addition to the discussion of a possible approach for the
"Bachat"

I add some questions.

Ron
----- Original Message -----
From: <A
href="mailto:adkarve@pn2.vsnl.net.in" title=adkarve@pn2.vsnl.net.in>A.D.
Karve
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Sent: Friday, April 13, 2001 8:20 AM
Subject: Re: Request for design assistance on a specific sized
charcoal making stove
>Dear Ron,
>our light biomass stove, called "Vivek", is a
stove in which light biomass (sawdust, threshing floor debris, dried leaves
etc.) is first >packed, around a central vertical column, after
which the column is removed to leave a vertical lumen in the biomass.

(RWL): 1. I once
worked with a young Indian with a first name of "Vivek". What is the
meaning of "Vivek"?
2. This has certainly much to be said for it
in terms of using a low cost fuel. I was not aware that you have been
testing this design with other than sawdust.
3. Is this the same stove that your daughter
studied for her Master's thesis and did she study fuels other than
sawdust?

>Fire, started at the bottom of this
lumen, gasifies the biomass and the gas is burnt at an opening at the top
of the stove.

(RWL): 1. Do you know whether anyone has ever
tried to start the flame at the top? It would seem to me to have a better
chance of being a pyrolyzer with most of the air introduced above the
"lumen"? The hope would be that it could be a "charcoal-maker"
- It might have a more constant output.

>These stoves are being popularised in
Maharashtra State by the Department of Forests, in order to encourage people to
use the >leaf litter as fuel and not to cut down the trees. The opening at
the top of this stove can be as narrow as 5 cm and as wide as one >wants it
to be. It produces a near blue flame, because it is the gas that is being
burnt.

(RWL): 1. I believe that
your daughter's thesis gave an optimum height for a specific diameter - what was
that ratio?
2. I presume that this was
moderately uniform in power output - but perhaps some variability as the "lumen"
gets progressively larger through the burn. Could you quantify in any way
this power output variability? Do you think there is any simple way to
make it more constant output?
3. I cannot recall what your daughter
said about the problem of "char" falling out periodically. Is this a
problem, and if so how can it be minimized?
4. Are there any major down-sides to the
stove? What has been consumer reaction to the stove? What is the
cost?

Yours Nandu

Again thank you for your continuing contributions to this dialog.

Ron
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Ron
Larson
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Cc: <A href="mailto:shirish@spacpl.com"
title=shirish@spacpl.com>Shirish B. Patel
Sent: Thursday, April 12, 2001 7:44
PM
Subject: Request for design assistance on
a specific sized charcoal making stove

Stovers -
As part of an off-line
dialog on the Bachat and ICMIC Indian steam cookers, I promised to ask
those on the list to report on any of their past, present, or future efforts
to achieve a small biomass-based charcoal-making cookstove with the properties
that the Bachat cooker people would like - 0.5 kW, 0.5 kWh, and a flame
diameter of about 7 cm (or less?).

We have been using 18
megajoules per kG and with 3.6 megajoules per kWh, this says we get about 5kWh
per kg - or that about 100 gms of biomass is needed for this job. With a
charcoal maker giving 25% charcoal by weight (with a charcoal yield of about
30 MJ/kg or about 40% by energy content), we should start with about 40% more
weight - about 140 grams (or 150 to allow for some
unknown inefficiencies?)

Anyone able to report on such
an effort? I am sure that the Bachat stove developers would be delighted
to hear of any relatively constant output wood-burning stove that worked with
anything near 100 - 150 grams.

As an aside, my past
expereince with these stoves says that one can use a cap with the desired exit
flame diameter - and that the fuel diameter can be different from 7 cm - although this might not be too
far off. I am guessing that we need a fuel height that is twice as large
- but haven't had the time to think this through. One hour of pyrolysis
time was possible with a larger diameter fuel container of 15 cm
diameter, but this had much greater output than 0.5 kW.

Anyone?

Thanks in advance -
Ron

From tmiles at trmiles.com Sun Apr 15 16:11:45 2001
From: tmiles at trmiles.com (Tom Miles)
Date: Tue Aug 31 21:36:51 2004
Subject: Fwd: activated charcoal
Message-ID: <4.3.2.7.2.20010415130759.00cd2f00@mail.teleport.com>

>Date: Sun, 15 Apr 2001 22:54:17 +0700
>To: owen@africaonline.co.ke
>From: ENHOLCO THAILAND <enholco@cscoms.com>
>Subject: activated charcoal
>Cc: rwedp@fao.org, auke.koopmans@fao.org, "John Flottvik" <jovick@island.net>,
> owner-stoves@crest.org, antal@wiliki.eng.hawaii.edu
>
>Dear Matthew,
>I have read your message re: Charcoal in East Africa where you mentioned
>charcoal factories in Lampang and the problems around the bamboo charcoal
>making. I have been living in Lampang for more than 10 years, coming here
>as a consultant for a local power plant and later staying on my own. The
>factory what I am running now for wooden kitchenware was run before for
>production of bamboo chopsticks. That time the huge bamboo waste was not
>so easy to make use of. i.e, nobody from the vast surrounding was keen on
>it. The burning for the charcoal in a large scale with the legal Thai
>wages had not been viable, it could be done only in a small scale by
>villagers. As far as I know they had run mostly on wood sawdust or
>surprisingly, on charcoal dust brought in over 2,000 km from the south.
>One of the charcoal factory you mentioned belongs to an older gentleman, a
>good friend of mine who I incidently yesterday was visiting. Currently,
>the production of both of these charcoal factories is down to zero because
>of the low market.
>I am now considering to dust it off and manufacture activated carbon.
>I would appreciate any hint on the activation process, how to implement a
>simple system for about 1 ton/day of activated charcoal and any other info
>about market.
>thanks and regards
>
>
>
>
>
>
>
>In case you would be available this April in Bangkok, we would like to
>invite you to visit:
>Bangkok International Gift & Housewares Fair, April 19 - 23, 2001,
>at new venue IMPACT (Northern part of Bangkok near Airport).
>We will be happy to see you at our booth DD36 (ICC - 1st level). Please
>let us know when about you would be around and whether you need more info
>(hotels, map, etc).
>
>regards
>Jan Mrskos
>ENHOLCO INDUSTRIES CO., Ltd.
>Wangprao KhoKha 52130
>Lampang Province
>Thailand
>tel. +66 54 349104
>fax +66 54 349105
>
>
>http://www.cmth.com/enholco/index.htm

Thomas R Miles tmiles@trmiles.com
T R Miles, TCI Tel 503-292-0107
1470 SW Woodward Way Fax 503-292-2919
Portland, OR 97225 USA

From ronallarson at qwest.net Sun Apr 15 21:36:28 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Fw: Price in India of 5 litre pressure cooker
Message-ID: <00e901c0c614$f7d5bf80$e57ce13f@computer>

stovers:

The following is further information on the (low) prices of metal goods
in India. Without knowing enough - I would say tht the Bachat is larger and
involves more work. But it appears that the prices are relatively similar.
The issue still remaining is which is the more efficient per kg of food
cooked. Hopefully at some point we will have definitive data.

Thank you, AD, for this additional data.

Ron

----- Original Message -----
From: A.D. Karve <adkarve@pn2.vsnl.net.in>
To: Ron Larson <ronallarson@qwest.net>
Cc: <abp@spaacpl.com>; Shirish B Patel <sbpatel@spacpl.com>; <agb@vsnl.com>;
<kishorem@bom3.vsnl.net.in>
Sent: Sunday, April 15, 2001 8:45 AM
Subject: Re: Price in India of 5 litre pressure cooker

> Dear Ron,
> I got this information from a local shop selling kitchen utensils. The
> price of pressure cookers of 5 litre capacity, manufactured by Indian
> manufacturers, ranges from Rs. 450 (US$ 10) to Rs. 500(US$ 11). These
> prices include profits of the manufacturer, wholeseller and retailer plus
> the costs of advertising, transport of material, sales tax, octroi (tax
> levied by the city administration) etc. The cost of Bachat (US$ 8 to9 on a
> no-profit basis) too would fall within the same range if profits and
> overhead expenses are added to it. The pressure cookers manufactured by
> internationally known manufacturers (e.g. Hawkins) cost more (around US$
> 20), but so would Bachat if it were manufactured by Hawkins.
> Yours Nandu
> ----- Original Message -----
> From: Ron Larson <ronallarson@qwest.net>
> To: Shirish B. Patel <shirish@spacpl.com>
> Cc: Aniruddha B Pandit <abp@udct.ernet.in>; J B Joshi <jbj@udct.ernet.in>;
> Rekha Singhal <rekha@foodbio.udct.ernet.in>; R S Shah
> <jaijui@bom8.vsnl.net.in>; G K Bhide <agb@vsnl.com>; kishore Mariwala
> <kishorem@bom3.vsnl.net.in>; Ray Wijewardene <raywije@eureka.lk>; A D
Karve
> <adkarve@pn2.vsnl.net.in>; Priyadarshini Karve <karve@wmi.co.in>
> Sent: Thursday, April 12, 2001 7:07 PM
> Subject: Re: Bachat and ICMIC cookers
>
>
> > ----- Original Message -----
> > From: Shirish B. Patel <shirish@spacpl.com>
> > To: Ron Larson <ronallarson@qwest.net>
> > Cc: Aniruddha B Pandit <abp@udct.ernet.in>; J B Joshi
<jbj@udct.ernet.in>;
> > Rekha Singhal <rekha@foodbio.udct.ernet.in>; R S Shah
> > <jaijui@bom8.vsnl.net.in>; G K Bhide <agb@vsnl.com>; kishore Mariwala
> > <kishorem@bom3.vsnl.net.in>; Ray Wijewardene <raywije@eureka.lk>; A D
> Karve
> > <adkarve@pn2.vsnl.net.in>; Priyadarshini Karve <karve@wmi.co.in>
> > Sent: Thursday, April 12, 2001 4:51 AM
> > Subject: Bachat and ICMIC cookers
> >
> >
> > > 12 April
> > > Dear Ron,
> > >
> > > >
> > > (2) Dr A D Karve says the tooling for Bachat is expensive, as it is
for
> > > pressure cookers. This is not correct. We get the Bachat parts made in
a
> > > small workshop in Bombay--there must be dozens of similar shops all
over
> > the
> > > city--the tooling has not cost us more than Rs 50,000 (about $ 1,000),
> and
> > > the finished cookers are offered by us on a no-profit, no-loss basis
for
> > Rs
> > > 350 ($ 8.00) for the 4.5 litre version and Rs 395 ($ 9.00) for the 6
> litre
> > > version. The price includes the inner stainless steel cooking vessels.
> > > Because Bachat is not pressurised, the aluminium walls are as thin as
> > > possible (any thinner and they tear during spinning) and the cost is a
> > > fraction of that of pressure cookers of similar capacity.
> > >
> >
>
>

From keith at journeytoforever.org Mon Apr 16 02:06:36 2001
From: keith at journeytoforever.org (Keith Addison)
Date: Tue Aug 31 21:36:51 2004
Subject: Keith Addison and Journey to Forever
In-Reply-To: <F13Cekp8tg1zSarY6FD00002358@hotmail.com>
Message-ID: <v0421010fb7003081c307@[61.121.36.47]>

"Ron Larson" <ronallarson@qwest.net> wrote:

>Hello Keith
>Stovers:
> This is my followup to a response a few days ago from Keith Anderson who
>had given some good guidance on biodigestion and then I had some followup
>questions based on having visited his web site, which is also mentioned
>below.

Hello Ron

Thanks very much for this - sorry it's taken me a few days to reply
(got swamped).

I've uploaded some photos and information on our problem charcoal
making stove. Thanks for the suggestion, Ron, but rather than trouble
Alex I put it on our website - also I don't think it'd merit a place
on Alex's site (great site!) until it works properly at least!
Anyway, it's here:
http://journeytoforever.org/teststove.html

Most grateful for any and all suggestions and comments, and not at
all sensitive about it - no need to be polite.

>This asks or answers a few more questions where appropriate:
>
> <SNIP>
>(Keith)
>
> > We're in Japan now, both as the final stage of project preparation
> > and the first part of the journey, though not at all a typical part.
> > We'll be here for a lot longer than other places, for one thing, we
> > have a lot of work to do here. I doubt we'll be leaving before the
> > end of the year.
> >
> > Re stoves, there's a stoves page on our site, maybe you saw it:
> > http://journeytoforever.org/at_woodfire.html
> >
>
> (RWL): Yes, I saw it and hope others on our list may let you now of
>something special they are doing that should place them on your list as
>well. I joined one group because you had it listed.

Please, yes - of course Alex's site is THE place to be, but I'm sure
all agree that these efforts need publicising, the more the merrier.
I know that some other quite big sites are pushing our stoves page,
so it could help.

> > But we're not stoves experts at all. We're hoping to develop working
> > relationships with some of the organisations and people referred to
> > on that page (who all seem to be members of this great list) when it
> > comes to finding good solutions at village level where appropriate
> > during our journey.
> >
> (RWL): I think you are the only list member writing from Japan. As you
>run into others please ask them to join (Japan or whereever)

Will do. I run the Biofuels list at Yahoo! Groups
(http://groups.yahoo.com/group/biofuel), which has about 600 members
now (mainly but not only biodiesel and ethanol), and I've referred
them to the Stoves list (and the GAS list) a few times, same with the
Homestead listers. I think some of them joined. I haven't met any
other stovers in Japan so far and our Japanese website hasn't got
that far yet (pending improvements to our stove), but when it does
I'm sure there'll be a response.

> > However, we have been working with stoves, but as one of our
> > education projects, and in fact it's ground to a halt because we're
> > baffled! I was about to ask the list for help. We've built four
> > smallish IDD stoves so far, each one better than the last, but still
> > far from good enough, and we don't know how to proceed.
> >
> (RWL): Please define IDD.

Tom answered you - Inverted Downdraft Gasifier, a charcoal making stove.

>(RWL): The person on our list with the greatest skill now in making
>beautiful small charcoal making stoves out of waste cans is Richard Boyt.
>As a retired potter, he probably has a special affinity also to Japan.
>(Richard - I hope you will enter this discussion on this novel use of waste
>chopsticks.)

Richard's 10-can stove looks wonderful, but I had great difficulty
following the drawings (so did a couple of Biofuels list members).

> Many of us will try to help with anything having to do with
>charcoal-making stoves. Give us the questions.

Many thanks.

> Best of luck on this incredible journey - still hope to join you on some
>part of it..
>
>Ron

Thankyou Ron. You'd be more than welcome to join us - plenty of time
still to plan something good. Wouldn't that be great?

Best wishes

Keith Addison
Journey to Forever
Handmade Projects
Tokyo
http://journeytoforever.org/

From keith at journeytoforever.org Mon Apr 16 02:07:41 2001
From: keith at journeytoforever.org (Keith Addison)
Date: Tue Aug 31 21:36:51 2004
Subject: Keith Addison and Journey to Forever
In-Reply-To: <67.12878563.28084397@cs.com>
Message-ID: <v04210110b7003916c762@[61.121.36.47]>

Tom Reed wrote:

>Dear Stovers:
>
>Ron asked...
><<
> (RWL): Please define IDD. >>
>
>I don't think Keith answered Ron. I presume IDD stands for the inverted
>downdraft gasifier.

Hello Tom

Now I've answered (bit tardily), and yes, that's what it stands for.
But you're too kind in thinking my using the term implied
understanding why it works - well, I do, sort of, but in fact I just
borrowed it from you. :-)

This is a nice, clear explanation, cleared up a few points - thanks very much!

Best wishes

Keith Addison

>This was my name, descriptive of what I developed from
>the conventional downdraft gasifier. The conventional downdraft gasifier
>uses the internal combustion engine to draw gas DOWN through first the
>biomass, burning the volatiles and then through the resulting charcoal,
>cracking some more tars and gasifying much of the charcoal.
>
>While it is convenient to draw the gas down and feed fuel on top, the hot gas
>flows in opposition to natural convection which prefers hot gases to go up.
>For this reason it is not possible to have a very slow rate of conversion,
>since natural convection overcomes slow forced downward conrvection.
>
>Facing this problem in 1985, I developed the "Inverted Downdraft Gasifier",
>IDD, in which the biomass is lit on the top and works down through the fuel
>mass, generating gases which rise by natural convection to the top where they
>are burned.
>
>The advantage is that the gas is generated very simply, suitable for stoves.
>
>One characteristic is that because of the very slow pyolysis, the charoal
>yield is quite high, typically 15-25% - and advantage if you want charcoal, a
>disadvantage if you want to convert all the fuel to gas.
>
>The disadvantage is that if you wish to extent the process it is necessary to
>auger fuel in at the bottom of the pile rather than pouring it top. However,
>since cooking is a batch process, the size of the container controls the
>energy output and cooking rate.
>
> ~~~~~~~~~~~
>The name may be too complicated for those not acquainted with gasification,
>and so Ron calls it a "charcoal making stove" or a "top burning stove"
>process.
>
>IDD implies an understanding of why it works. Thanks Keith....
>
>TOM REED

From ronallarson at qwest.net Tue Apr 17 00:35:09 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Fw: Forwarding AD Karve on the "Vivek" "sawdust" stove
Message-ID: <01d801c0c6f6$f15974c0$857de13f@computer>

Stovers:
The following contains further
good information on the "vivek". I have interspersed a few more
questions.

AD: Thanks again for very good new
information. This now sounds like a very good possible choice for the
Bachat. See a few more questions.

Ron

----- Original Message -----
From: <A
href="mailto:adkarve@pn2.vsnl.net.in" title=adkarve@pn2.vsnl.net.in>A.D.
Karve
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Cc: <A href="mailto:karve@wmi.co.in"
title=karve@wmi.co.in>karve@wmi.co.in
Sent: Monday, April 16, 2001 12:37 PM
Subject: Re: Forwarding AD Karve on the "Vivek" "sawdust"
stove

Dear Ron,
1. Vivek means, responsible and thoughtful
behaviour (the opposite of rash and thoughtless action).
2. As I stated, this stove works with any biomass
in the form of small particles or pieces, like paper waste from a printing
press, paper coming out of a shredding machine, dry leaves, groundnut
(peanut) shells, soybean shells, panicle debris of sorghum and pearl millet left
after threshing, cottonseed hulls, etc.
3. Vivek was the outcome of my daughter's
thesis. We never tested it with a top to down fire, but I have asked my
colleagues to try it.

(RWL): Unfortunately,
there will probably have to be a primary air control and additional height to
assure combustion of the (postulated) pyrolysis gases. This may be too
much extra to have good success. But I hope it works.

4. When the ratio of lumen diameter:lumen
height is 1:6, the biomass burns completely leaving only ash behind. In
Vivek, we adhered to this ratio and avoided the problem of leftover
char. In the domestic model of Vivek, the diameter of the lumenis 5
cm, and the stove height is 30 cm. The quantity of biomass that
is packed around the central lumen determines the period of
burning. The lumen does not become wider as the stove burns,
because when the biomass burns, its place is taken by ash. As long as the
stove is not shaken, the ash remains in place. That is why tight packing of the
biomass is so important in the first place. If the ash or the burning biomass
were to collapse, the lumen would be blocked and the stove would cease to
function properly.

(RWL): 1) A while ago we
had a discussion of burning paper - and someone noted the use of an internal
"screen" to prevent collapse of the "char/ash". Maybe something similar
here would help.
2) In your "domestic"
model, what is the OD of the fuel supply? What is the weight of the fuel
supply?

5. Char certainly poses a problem in this
stove as it is powdery and always mixed with ash. Our Vivek
stove has been designed to burn the fuel completely, without leaving any char
behind. A normal rural household does not use charcoal, becasue it
needs a special stove. Most rural households have a typical wood burning stove.
Wood always produces a tall flame. Therefore in a wood burning stove, the
pot rests about 10 to 12 cm above the burning wood. In a charcoal stove, the pot rests just 2 or 3 cm
above the glowing coals.

(rwl): The above is correct.
The generation of charcoal during cooking is certainly not the best choice
in every case. Having a big existing need for charcoal is one good reason
to promote charcoal-makings stoves - which was the case in Sudan. However,
there may be other local applications for charcoal (water purification?,
restaurants? , other users?) I know of no other way to make money
while cooking for the family.

6. Housewives have not accepted Vivek readily,
because it does not allow them any control over the flame
intensity. Stoves of this type were popular in the urban centres, about 60 years
ago, when kerosene was not available due to WW2. The villagers always used and
still use wood as fuel. In a typical wood burning stove, one can
regulate the intensity of the flame by controlling the quantity of wood
being burnt at a time. One can also easily extiguish the stove by removing
the wood from the stove and light it again whenever required. I suggested
Vivek for use with Bachat cooker, becasue in the case of Bachat cooker one
requires a steady flame for a particular period of time, after which the
fire should be automatically extinguished. This is possible with Vivek
stove having the desired fuel capacity, so that it would extinguish itself
after the fuel is burnt out.

(RWL): I agree with this
assessment. But the advantage in a charcoal-making stove
of controlling power output (a "turn-down" ratio) may still be a reason
for thinking pyrolysis. The addition of primary air control may still
be possible with the vivek as noted above.

7. Cost of Vivek would be about Rs. 100 if it is
fabricated from 16 or 18 guage iron sheet, and more if one were to use stainless
steel. But some of the potters that you met in Pune conference make
this stove by making a cylindrical hole into the cooking
platform. After packing the fuel into this hole, one places a
detachable terra cotta top plate with a central hole and three pot raisers
on this hole. Such stoves would be much cheaper. During WW2, people
made these stoves themselves from any old tin can.
Yours Nandu

(RWL): Do you have any
data on the relative efficiency of the sheet metal vs "pottery" (tamped earth?)
vivek versions? Is the Vivek always made with a horizontal hole - or can it work
with only a central vertical lumen? What is the reason that the "old tin
can" approach has (apparently) diappeared?

Again thank you for this further information.
I think the great thing about the vivek is the use of agricultural
residues!! We should all be doing as much as we can to promote the use of
these materials which are so often burned only in the fields. You in ARTI
are to be greatly congratulated on your efforts to promote this "waste"
resource.

Ron
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
-----

Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Ron
Larson
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Sent: Sunday, April 15, 2001 9:04
AM
Subject: Forwarding AD Karve on the
"Vivek" "sawdust" stove

stovers:

The following is a useful
possible addition to the discussion of a possible approach for the
"Bachat"

I add some questions.

Ron
----- Original Message -----
From: <A
href="mailto:adkarve@pn2.vsnl.net.in" title=adkarve@pn2.vsnl.net.in>A.D.
Karve
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Sent: Friday, April 13, 2001 8:20 AM
Subject: Re: Request for design assistance on a specific sized
charcoal making stove
>Dear Ron,
>our light biomass stove, called "Vivek", is a
stove in which light biomass (sawdust, threshing floor debris, dried leaves
etc.) is first >packed, around a central vertical column, after
which the column is removed to leave a vertical lumen in the biomass.

(RWL): 1. I once
worked with a young Indian with a first name of "Vivek". What is
the meaning of "Vivek"?
2. This has certainly much to be said for
it in terms of using a low cost fuel. I was not aware that you have been
testing this design with other than sawdust.
3. Is this the same stove that your
daughter studied for her Master's thesis and did she study fuels other than
sawdust?

>Fire, started at the bottom of this
lumen, gasifies the biomass and the gas is burnt at an opening at the top
of the stove.

(RWL): 1. Do you know whether anyone has
ever tried to start the flame at the top? It would seem to me to have a
better chance of being a pyrolyzer with most of the air introduced above the
"lumen"? The hope would be that it could be a "charcoal-maker"
- It might have a more constant output.

>These stoves are being popularised in
Maharashtra State by the Department of Forests, in order to encourage people
to use the >leaf litter as fuel and not to cut down the trees. The opening
at the top of this stove can be as narrow as 5 cm and as wide as one >wants
it to be. It produces a near blue flame, because it is the gas that is being
burnt.

(RWL): 1. I believe that
your daughter's thesis gave an optimum height for a specific diameter - what
was that ratio?
2. I presume that this
was moderately uniform in power output - but perhaps some variability as the
"lumen" gets progressively larger through the burn. Could you quantify
in any way this power output variability? Do you think there is any
simple way to make it more constant output?
3. I cannot recall what your
daughter said about the problem of "char" falling out periodically. Is
this a problem, and if so how can it be minimized?
4. Are there any major down-sides to the
stove? What has been consumer reaction to the stove? What is the
cost?

Yours Nandu

Again thank you for your continuing contributions to this dialog.

Ron
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Ron
Larson
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Cc: <A href="mailto:shirish@spacpl.com"
title=shirish@spacpl.com>Shirish B. Patel
Sent: Thursday, April 12, 2001 7:44
PM
Subject: Request for design assistance
on a specific sized charcoal making stove

Stovers -
As part of an off-line
dialog on the Bachat and ICMIC Indian steam cookers, I promised to ask
those on the list to report on any of their past, present, or future efforts
to achieve a small biomass-based charcoal-making cookstove with the
properties that the Bachat cooker people would like - 0.5 kW, 0.5 kWh, and a
flame diameter of about 7 cm (or less?).

We have been using 18
megajoules per kG and with 3.6 megajoules per kWh, this says we get about
5kWh per kg - or that about 100 gms of biomass is needed for this job.
With a charcoal maker giving 25% charcoal by weight (with a charcoal yield
of about 30 MJ/kg or about 40% by energy content), we should start with
about 40% more weight - about 140 grams (or 150 to allow for some
unknown inefficiencies?)

Anyone able to report on
such an effort? I am sure that the Bachat stove developers would be
delighted to hear of any relatively constant output wood-burning stove that
worked with anything near 100 - 150 grams.

As an aside, my past
expereince with these stoves says that one can use a cap with the desired
exit flame diameter - and that the fuel diameter can be different from 7 cm - although this might not be too
far off. I am guessing that we need a fuel height that is twice as
large - but haven't had the time to think this through. One hour of
pyrolysis time was possible with a larger diameter fuel container of 15
cm diameter, but this had much greater output than 0.5 kW.

Anyone?

Thanks in advance -
Ron

From ronallarson at qwest.net Thu Apr 19 00:47:29 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:51 2004
Subject: Fw: Your queries about Vivek stove, charcoal, etc.(from AD Karve - part 1)
Message-ID: <000401c0c88b$4d1b0680$46f2b4d1@computer>

Stovers - additional dialogue on the vivek stove
(from A.D. Karve)

More questions and comments
below as well
----- Original Message -----
From: <A
href="mailto:adkarve@pn2.vsnl.net.in" title=adkarve@pn2.vsnl.net.in>A.D.
Karve
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Cc: <A href="mailto:karve@wmi.co.in"
title=karve@wmi.co.in>karve@wmi.co.in
Sent: Tuesday, April 17, 2001 7:41 PM
Subject: Re: Your queries about Vivek stove, charcoal,
etc.

Dear Ron,
1.What does OD stand for (oxygen demand? outer
diameter? )?

(RWL): Yes outer diameter
- to get at volumes

2.A big user of charcoal in the former days was the
traditional village blacksmith. But nowadays, at least in those parts of
India where I live, the traditional smithy has been replaced by fabrication
workshops with modern metalworking equipment. Restaurants have switched to
modern fuels like propane but they still use charcoal for specific jobs (making
a particular form of bread called Tandoori nan). Roadside vendors who roast
cobs or peanuts by the roadside and sell them, also use charcoal. But the
professional users always purchase their charcoal from traditional supliers, who
make charcoal on a commercial scale. A housewife making charcoal and
selling it in small lots, is absolutely a novel concept, at least as far as our
part of India is concerned. But as I mentioned in my previous communication, the
char coming out of a light biomass stove would be powdery and also mixed with
ash. In this form it is absolutely useless to anybody.

(RWL): 1. India is
way ahead of almost every country in Africa. I imagine a charcoal-making
stove will be less valuable in India - unless its other attributes (clean
cooking, controllability, etc) overcome the inconvenience of working with
charcoal at the end.
2. My interest in
charcoal making stoves largely rises from trying to do away with the traditional
("commercial") scale production methods which typically are quite awful.
Can you describe how most charcoal is produced in India?
3. One of the greatest
pleasures in my life has been eating tandoon (tandoor?) nan.
4. I believe all charcoal
making involves the careful control of air - usually a minimum of two air
supplies. The vivek will have to be modified to separate primary and
secondary air - as is being done in the Bachat pyrolysis stove - but they have
not yet been collecting charcoal.
5. Throughout Africa
you will see bags of charcoal lined up along rural roads for sale.
Someone will show up quickly to take your money if you stop to bargain.
Travelers never buy their charcoal in their home cities. But if the stove
is good enough and such roadside pickups don't find enough customers, the
superior combustion characteristics of charcoal will ensure that it will be
used. It won't be thrown away anywhere.
6. The charcoal
coming out of a true charcoal-making stove rarely has any ash associated with
it.
3.Light biomass (such as dried sugarcane leaves and
wheat stover) which is of no use as cattle feed and which is too light to be
burnt directly in a stove, can be successfully charred by using the retort
process. This process was demonstrated to the delegates of Pune conference
during their field visit to Phaltan. The char obtained through this process
contains no ash, because the pyrolysis of the biomass takes place under
exclusion of air. This char too has to be converted into briquettes in
order to make it into a useful product. This product has a good market,
because it is produced in larger quantities and available to the user as a
standard and reliable product. Also a ban introduced by our government on making
charcoal from wood (in order to save the forests) has indirectly helped us in
promoting our briquettes.

(RWL): 3-1. A somewhat
similar principal (air exclusion) is of course applied in all charcoal-making
stoves (with Dr. Grover especially having designed several stoves that work on
the retort principle). Stoves using the retort principle have much slower
response time compared to that in which primary air is flowing through the
pyrolysis region.
3-2. My objection to pyrolysis in the field is
that the majority of the available energy is lost. I have a "gut"
feeling that better economics will result from producing a better processed fuel
in the field and then pyrolyzing that "briquette" (a "cigar"?) in the
home

4. There is a valid reason for people not to make
the light biomass stoves out of old tin cans, because, as mentioned in my
previous communication, this concept itself has not been very popular with the
housewives as this stove denies control over flame intensity. Also,
when the first load is burnt out, it is quite an elaborate operation to remove
the ash and reload the stove. People now have better fuels such as propane and
kerosene, which offer the housewife the convenience of turning the flame
high or low at will. Therefore, those who can afford it have turned
to these fuels and those who cannot, still use wood or dung cakes, which
too offer better control of flame intensity than the sawdust
stove. Also turning the stove off and lighting it again at any time, are
conveniences, which Vivek does not offer. If one insists on biomass based fuels
and still wants the above conveniences, biogas, ethanol and methanol are the
better alternatives.

(RWL): 1. All your
rationales are appropriate. Controllability is a decided advantage - one
reason for promoting a charcoal-making stove. We regularly achieve a
turn-down ratio of about 3 (kWmax/kWmin).
2. I see three
questions -
a) can the existing Vivek add
some feature (a controllable air inlet) that allows an acceptable degree of
controllability - even if not rapid and not charcoal-making
b) can the existing Vivek be
turned into a controllable pyrolyzing or charcoal-making stove - using top
lighting, air control, a combustion/chimney, etc
c) can the existing
charcoal-making stoves be modified to allow the same "loose" fuels as used
in the Vivek? (I think already proven is that they can use pellets made
from such fuels)
3. Your point on the
problems of batch-loading is a good one. At least one of Dr. Grover's
retort stoves (a donut shape with internal combustion of the pyrolysis gases)
did allow for restarting. The answer to not being able to relight is not
yet clear - other than getting experience.

Yours Nandu

From ronallarson at qwest.net Thu Apr 19 00:48:59 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:52 2004
Subject: queries about the "Vivek" "sawdust" stove (forwarding from AD Karve, part 2)
In-Reply-To: <01d801c0c6f6$f15974c0$857de13f@computer>
Message-ID: <000701c0c88b$50517960$46f2b4d1@computer>

Stovers: Again more responses and
questions/comments

<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
A.D.
Karve
To: <A
href="mailto:ronallarson@qwest.net" title=ronallarson@qwest.net>Ron Larson

Cc: <A href="mailto:karve@wmi.co.in"
title=karve@wmi.co.in>karve@wmi.co.in
Sent: Wednesday, April 18, 2001 1:17
AM
Subject: Re: queries about the "Vivek"
"sawdust" stove

Dear Ron,
After having sent off answers to some of your
queries, I realised that some still remained to be answered.
You questioned the need for the horizontal part
of the lumen in the light biomass stove. Firstly, for those who have not
handled this stove, a small explanation. The stove consists of a
cylindrical vessel. It has a hole in the side wall near the bottom of
the vessel. Before filling this stove with biomass, one pushes a
wooden dowel through this hole, and holds with the left hand (or with the
right hand, if the user is left handed) a cylindrical wooden
pivertically in the centre of the vessel. The lower end of the wooden
vertical piece should touch the horizontal dowel. Using one's right
ece hand, powdered biomass is packed around the vertical wooden
piece. When the vertical and the horizontal pieces are removed, an "L"
shaped cavity is left in the biomass. You wanted to know if the horizontal
member of the cavity was necessary. The answer is that it serves as
a port of entry for tinder with which the biomass is
ignited.

(RWL): I asked partly
because with top-lighting (essential for a charcoal-making stove) one wouldn't
use this lower part of the "L". And I think performance would not be as
good as if the hole went allthe way to the bottom. But also I
asked because there may be some other advantages (in loading or air control or
something) to doing without the lower part of the L. Apparently
not investigated.

Another question of yours was about the weight of
the biomass. Our domestic model has 30 cm height and diameter of
about 20 cm. It is packed with powdered biomass, leaving in the biomass, the L
shaped cavity mentioned above. This particular model accepts between one and
two kg of biomass.The weight depends upon the density of the biomass and the
density of packing. Dried leaves generally weigh less, because the leaf
parenchyma has a lot of air spaces. Sawdust, paper shreds or peanut hulls
would weigh more.

(RWL): I deduce from
this since they (the Bachat developers) want about 10% of this weight or
energy output, they should reduce all dimensions by the cube root of 10 - or
about 2.15. This gives an inner (lumen) diameter of about 2.3
cm (maybe our one inch would work), a height of maybe 15 cm (6 inches), and an
outer diameter of maybe 8 to 9 cm (3 to 3.5 inches).

The third question of yours was about the
relative efficiency of the metalllic Vivek vs. the clay Vivek. I must confess
that we have not measured them. Intuitively I feel that the metallic
Vivek would be less efficient because of heat loss from the metallic body. But
Tom Reed may argue that in the clay model, which is incorporated in the
kitchen platform, the heat may not be lost to air, but is lost to the kitchen
platform.

(RWL): 1. I ask
because if you have two units of similar size, the efficiency answer would be
quite interesting. Placing equal (this may be difficult - but perhaps
achievable just by tamping differently) amounts of fuel and water (in the same
types of pan) and measuring the differences in water boiled away should be a
not too time-consuming a test.
2. Presumably the
ceramic version can be fired two different ways - in the air, or embedded in a
clay kitchen platform.
3. Presumably the metal
version lasts longer. What difference in costs?

Yours Nandu

(RWL): Thank you again
for such good answers. It would be nice if the Bachat could use this
approach.

From elk at wananchi.com Fri Apr 20 07:09:19 2001
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:36:52 2004
Subject: testing
Message-ID: <000e01c0c98a$2a3bb600$d540083e@default>

My apologies if this clutters up inboxes- I have
sent two messages to the list recently that have not been copied back to
me.

Ronal, Tom- are you getting 'bounced' messages from
my account?

This morning I asked the group for advice on the
best and least complex way of testing charcoal and raw biomass such as sawdust
for moisture content..... what are the standard temperatures and times for ovens
and if a microwave can work.

Also- and of some urgency- I would like to know if
charcoal from different sources- like hardwood VS softwood, rice husk,
bagasse and the like emit significantly different amounts of carbon
monoxide. Can one type of charcoal be potentially more toxic than another? Also,
any comparative info on CO emissions for popular domestic fuels used in
developing countries would be appreciated.

Thanks;

elk

--------------------------Elsen L.
Karstadelk@wananchi.com<A
href="http://www.chardust.com">www.chardust.comNairobi
Kenya

From ronallarson at qwest.net Fri Apr 20 09:23:31 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:52 2004
Subject: Fw: Your queries about Vivek stove, charcoal, etc.(from AD Karve)
Message-ID: <01cc01c0c99a$8f009320$907ee13f@computer>

Stovers: Another message from Dr. Karve,
Sr.

----- Original Message -----
From: <A
href="mailto:adkarve@pn2.vsnl.net.in" title=adkarve@pn2.vsnl.net.in>A.D.
Karve
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Sent: Thursday, April 19, 2001 9:28 PM
Subject: Re: Your queries about Vivek stove, charcoal, etc.(from AD
Karve)

Dear Ron,
Your comments and queries and my reactions are as
follows:
1. "My interest in charcoal making stoves
largely rises from trying to do away with the traditional ("commercial") scale
production methods which typically are quite awful. Can you describe how
most charcoal is produced in India?"

Unfortunately, charcoal
is still made in very crude kilns, which pollute the atmosphere. I
remember having seen a modern pilot plant in Pune, for destructive distillation
of wood. This plant produced high grade (activated) charcoal, tar, acetone
etc. It was later handed over to the Department of Forests, Maharashtra
Government, which serves as a burial ground for bright new ideas. And that
is exactly what happened to this plant. 

(RWL): Terrible
shame! Maybe the cooking industry can help.

2. "One of the greatest pleasures in my life
has been eating tandoon (tandoor?) nan."
Tandoor is the stove in which this bread is baked
and therefore the bread itself is called TANDOORI NAN. NAN or NUN (pronounced
noon) is the persian word for bread.

(RWL):
Thanks.

3. "My objection to pyrolysis in the
field is that the majority of the available energy is lost. I have a
"gut" feeling that better economics will result from producing a better
processed fuel in the field and then pyrolyzing that "briquette" (a "cigar"?) in
the home"

We have started working on the suggestion
made by Tom Reed to torrefy the biomass in order not to lose too much of the
volatile combustible matter in the biomass. Compressing light biomass into
briquettes requires too much energy to be spent to overcome the springy and
elastic nature of this material. Our preliminary experiments with
torrefication showed that light toasting of the biomass made the biomass
brittle, so that it could be very easily pulverised. This powder, mixed
with starch paste, could easily be extruded into briquettes.

(RWL): In Pune, you and I
talked about whether there might be a low energy means of producing a long
"rope" in the field. I hope anyone knowing of any such method will chime
in. This cold remove the need for both the torrefing step and the
briquetting step.

4. " 2. I
see three questions -
a) can the existing Vivek add
some feature (a controllable air inlet) that allows an acceptable degree of
controllability - even if not rapid and not charcoal-making
b) can the existing Vivek be
turned into a controllable pyrolyzing or charcoal-making stove - using top
lighting, air control, a combustion/chimney, etc
c) can the existing
charcoal-making stoves be modified to allow the same "loose" fuels as used
in the Vivek? (I think already proven is that they can use pellets made
from such fuels)"

I have asked my stove colleagues to see if Vivek
can be modifying along these lines. As far as (c) is concerned, we shall conduct
some trials to find out if Vivek would work with small sticks or wood chips.

(RWL): Thanks. We look forward to results -
which won't be easy, I know.

5. "I deduce from this since they (the Bachat developers) want about
10% of this weight or energy output, they should reduce all dimensions by the
cube root of 10 - or about 2.15.  This gives an inner (lumen)
diameter of about 2.3 cm (maybe our one inch would work), a height of maybe 15
cm (6 inches), and an outer diameter of maybe 8 to 9 cm (3 to 3.5
inches)."

Theoretically, the dimentions look all right, but
Shirish wanted a flame diameter of 7 cm. We too faced a similar problem
with our Vivek. Indian housewives use a griddle for roasting their
unleavened bread, which can a diameter of 40 cm. To heat such a broad utensil
uniformly, one needs a broad flame having a diameter of about 20 cm.
Following our diameter to height ratio, we would have required Vivek to be
120 cm (4 feet) tall! Priya solved this problem by fabricating a Vivek with
three vertical lumens of 5 cm each. The stove height of 30 cm sufficed in this
case.   The three flames together could heat the broad griddle
uniformly, which satisfied the users. But as I said, the concept of Vivek
itself was not very attractive to the housewifes, because they could not control
the flame intensity and because restarting the stove after extinguishing it was
too much of a bother.

(RWL): 1. I was hoping that
Shirish would settle for anything that was less than 7 cm diameter. As he
is boiling water, and not heating a griddle, perhaps the smaller diameter will
suffice. (Shirish - can you tell us?)
2. In Ethiopia, just before this
list started up in 1995, I worked for a month developing a charcoal-making stove
which was needed for making the national bread called enjira - done on ceramic
griddles of about 60 cm diameter. As in your case, a small flame was
totally unacceptable. I found that a conical chimney flaring from about 30
cm to 60 cm gave quite an acceptable uniformity and power output (theirs is a
very energy intensive form of cooking).   In traditional enjira
cookers (often three stones, or same with shielding), the women learn how to
bank the fire, add fuel judiciously, and use burning charcoal embers in
crucial spots.

Yours Nandu

(RWL) Thank you again. We
seem to be running out of questions!! Now back to Shirish (who has been
having some trouble with our "stoves" list.
Ron

From tmiles at teleport.com Fri Apr 20 14:32:47 2001
From: tmiles at teleport.com (Tom Miles)
Date: Tue Aug 31 21:36:52 2004
Subject: Stoves Archives
Message-ID: <4.3.2.7.2.20010420112735.0266cdb0@mail.teleport.com>

Stovers,

The Stoves list archives are now available again at the new crest site:

http://www.crest.org/discussion/stoves/current/

Regards,

Tom Miles
Thomas R Miles tmiles@trmiles.com
T R Miles, TCI Tel 503-292-0107
1470 SW Woodward Way Fax 503-292-2919
Portland, OR 97225 USA

From ronallarson at qwest.net Fri Apr 20 15:02:41 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:52 2004
Subject: Fw: testing
Message-ID: <021b01c0c9c8$294b0b40$907ee13f@computer>

Stovers:

I replied to Elsen off-line -
because his message was about "crest" somehow messing up his messages I
also sent the question to Kirk Smith who has done some of the few accurate
measurements for CO on rural stoves. Kirk responded as shown below.
I went to Kirk's impressive web site and recommend it to all.

I think the most pertinent of
the many pertinent papers shown there is a June 2000 report done for the US|EPA
(# 00-052) showing a lot of Indian stoves and quite a few fuels. On or
about page 30 was a statistic that the CO/CO2 ratio for charcoal combustion was
about 0.2 - much higher than I would like to see. I don't have time right
now to read it all (I leave in 18 hours for five days at our annual ASES meeting
in Washington DC), but think this is a good start at Elsen's question. It
doesn't seem to answer the more detailed question from Elsen - but maybe there
are details there. I promise to read it more carefully later.

Anyone able to answer
more? Anyone know of a better paper?

I noticed in the past week that
Kirk is soon giving a major presentation on rural stove issues before some UN
group. Rogerio Miranda is on the same panel. I
hope one or both (and/or others) will report on what happened at that
meeting.

Kirk - thanks for the
lead. You do good work.

Ron

----- Original Message -----
From: <A
href="mailto:krksmith@uclink4.berkeley.edu"
title=krksmith@uclink4.berkeley.edu>Kirk R. Smith
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson ; <A href="mailto:elk@wananchi.com"
title=elk@wananchi.com>elk
Cc: Tom
Miles
Sent: Friday, April 20, 2001 8:57 AM
Subject: Re: testing

See papers listed under "online pubs" in the website
below/K
<snip>
----------------------------------------------------------------------------Prof.
Kirk R.
Smith
Chair, Environmental Health
Sciences
SPH, 140 Warren #7360 University of
California Berkeley
CA
94720
Phone: 510-643-0793 Fax: 510-642-5815

Website: <A href="http://ehs.sph.berkeley.edu/krsmith/"
eudora="autourl">http://ehs.sph.berkeley.edu/krsmith/Email:
Krksmith@uclink4.berkeley.eduSenior Fellow, EnvironmentEast-West
Center, Honolulu HI

From Reedtb2 at cs.com Sun Apr 22 06:39:53 2001
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:52 2004
Subject: Modern Enjira Cooking
Message-ID: <4f.a861d0b.28140e62@cs.com>

Dear Nandu, Ron, Neway et al:

Nandu writes (or Ron?)

<< In Ethiopia, just before this list started up in 1995, I worked for a
month developing a charcoal-making stove which was needed for making the
national bread called enjira - done on ceramic griddles of about 60 cm
diameter. As in your case, a small flame was totally unacceptable. I found
that a conical chimney flaring from about 30 cm to 60 cm gave quite an
acceptable uniformity and power output (theirs is a very energy intensive
form of cooking). In traditional enjira cookers (often three stones, or
same with shielding), the women learn how to bank the fire, add fuel
judiciously, and use burning charcoal embers in crucial spots.
~~~~~~

MODERN ENJIRA COOKING

The Enjira is a "pancake like bread that is used to pick up other foods. It
is made from fermented grain, so is mildly risen (leavened).

The traditional 60 cm diameter Ejira (Injira?) is cooked on a ceramic
griddle, about 2 cm thick, no doubt evolved over 5000 years (soon after
leavening was invented?).

Since this ceramic is a poor heat conductor and a great heat sink, it is
necessary to have a heat source approximately this large - a campfire, a
barbecue etc. Any flame or charcoal this size is going to waste incredible
amounts of heat.

How much heat is required for efficient Enjira cooking?

In Denver the Ethiopian community is satisfied to eat 40 cm Enjias - not what
mother cooked, but close enough. They are cooked on a Teflon coated
aluminum griddle that is electrically heated with a single calrod at about
the 10 cm radius (20 cm diameter). Only copper has better heat conduction
than aluminum. (About 0.5 W/cm-C). The test of uniformity is to look at the
resulting "pancake" and see if it is uniformly brown. It is. I have both
videos and stills of the commercial operation in Denver.

We have such a cooker in our lab. It is rated at 1300 Watts when on. It has
a thermostat so that when it reaches about 250C it cycles to maintain this
temperature, probably consuming about 900 Watts. (Neway could test this.)
We have measured the variation in temperatue in the surface with a radiation
thermometer and there is less than 20 C difference between the hot spot at 20
cm diameter and the center and edges. (I am on the road, so don't have exact
figures with me.)

If we promote an aluminum substitute for the ceramic disk in the city, the
problem will be to have a low enough intensity heat source. Our Turbo stove
operates at 3 kW full on, about 1300 Watts at maximum turndown. One can move
the Metad farther from the flame to get even lower temperatures. It iwill be
necessary for the housewife to make these final adjustments.

If this is sucessful it should result in a great deal of fuel saving, more
convenient cooking on the tefon surface and faster meal preparation.

Comments?

Yours truly, TOM REED, BEF/CPC

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From Reedtb2 at cs.com Sun Apr 22 06:41:29 2001
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:52 2004
Subject: Fw: Price in India of 5 litre pressure cooker
Message-ID: <9c.dbcd1b3.28140e6a@cs.com>

Dear Nandu, Ron and all:

I too have been impressed at how inexpensive well manufactured goods are in
India. While you were admiring mud stoves in villages we went into Pune and
I bought eight nesting stainless steel canisters to use for making stoves
here. Cost about $20. I also bought a kerosene cooker for about $10 that
works very well and that I have studied and demonstrated..

India could well be the economic engine for stove development. I would love
to be able to take an improved stove design to India for mass production and
sales around the world.
~~~~~~~~~
Unfortunatately, I also get the impression that it is hard to work with
commercial groups in India. They don't recognize intellectual property
rights and have a different view of business ethics than we do.

I would be happy to hear from Nandu that my impression is wrong.

Yours truly, TOM REED

In a message dated 4/15/01 6:34:57 PM Pacific Daylight Time,
ronallarson@qwest.net writes:

<<
stovers:

The following is further information on the (low) prices of metal goods
in India. Without knowing enough - I would say tht the Bachat is larger and
involves more work. But it appears that the prices are relatively similar.
The issue still remaining is which is the more efficient per kg of food
cooked. Hopefully at some point we will have definitive data.

Thank you, AD, for this additional data.

Ron

----- Original Message -----
From: A.D. Karve <adkarve@pn2.vsnl.net.in>
To: Ron Larson <ronallarson@qwest.net>
Cc: <abp@spaacpl.com>; Shirish B Patel <sbpatel@spacpl.com>; <agb@vsnl.com>;
<kishorem@bom3.vsnl.net.in>
Sent: Sunday, April 15, 2001 8:45 AM
Subject: Re: Price in India of 5 litre pressure cooker

> Dear Ron,
> I got this information from a local shop selling kitchen utensils. The
> price of pressure cookers of 5 litre capacity, manufactured by Indian
> manufacturers, ranges from Rs. 450 (US$ 10) to Rs. 500(US$ 11). These
> prices include profits of the manufacturer, wholeseller and retailer plus
> the costs of advertising, transport of material, sales tax, octroi (tax
> levied by the city administration) etc. The cost of Bachat (US$ 8 to9 on a
> no-profit basis) too would fall within the same range if profits and
> overhead expenses are added to it. The pressure cookers manufactured by
> internationally known manufacturers (e.g. Hawkins) cost more (around US$
> 20), but so would Bachat if it were manufactured by Hawkins.
> Yours Nandu >>

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From ronallarson at qwest.net Sun Apr 22 22:45:51 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:52 2004
Subject: Forwarding Shirish on Bachat or REDI stove
In-Reply-To: <006101c0cae9$c4f11ae0$f326fea9@sbplaptop>
Message-ID: <00cc01c0cb9f$4dc3f3a0$1eedc0d8@computer>

Stovers: The following message gives a bit more information on work going
on in India on at stove being developed for the Bachat Cooker.

----- Original Message -----
From: Shirish B. Patel <shirish@spacpl.com>
To: Ron Larson <ronallarson@qwest.net>
Cc: Aniruddha B Pandit <abp@udct.ernet.in>; kishore Mariwala
<kishorem@bom3.vsnl.net.in>; G K Bhide <agb@vsnl.com>; R S Shah
<jaijui@bom8.vsnl.net.in>
Sent: Saturday, April 21, 2001 9:53 PM

> 22 April
>
> Dear Ron,
>
>
<snip a paragraph on a list reception problem>
>
> We expect to soon receive a specimen of the stove developed by Prof H S
> Mukunda. They call it the REDI stove. RED stands for Reverse Downdraft and
> RED was what the stove was initially called. The 'I' for the Indian
> Institute of Science was then added to make the name 'REDI', which had the
> merit of sounding like "Ready". Once we have that stove we will be
> starting trials. I did not describe the arrangement they have for
> controlling primary air flow. Let me see if I can explain that in words,
> without a diagram. Between the floor of the stove (a solid disk) and the
> grating that supports the wood chips is an air space about 4 cm high. The
> wall of this cylindrical air space is continuous with the wall of the fuel
> chamber above, but is punctured at one place with a hole about 3 cm dia.
> Projecting outside from this hole is a short stub of pipe, open at both
> ends, with a number of radially drilled holes around the pipe. The pipe
has
> a cap, consisting of a sleeve that fits closely (but not tightly) over the
> pipe, with the outer end closed. The sleeve of the cap has similar
radially
> drilled holes which match the holes in the stub of pipe projecting from
the
> stove. By rotating the cap one can regulate the primary air flow, from
zero
> to the full aperture of all the holes combined. The cap is put on after
the
> stove has been lit and got properly going. Lighting is from below in this
> case, not from the top as in the case of wood chips and pyrolisis.
>
(RWL) : This sounds like a unique and fine means of primary air
control. I do not recall any quite like this.
I believe it can be used for top lighting (charcoal making) as well.

I do not have any experience with the combination of controllable air
and bottom lighting - as I have only been interested in the making of
charcoal - which requires top lighting. If it works and you are not
interested in the process of making charcoal there is certanly no reason
not to do this. Please let us know more about the success you have with
controlling power output by controlling air supply. I have been assuming
that there would not be enough uniformity in power output - which somehow
miraculously occurs with the charcoal-making, top-lighting approach.

> Prof Mukunda showed me another stove, very similar to the description of
the
> Vivek stove, for burning any kind of pulverised fuel--he showed me the
stove
> working when packed with sawdust. I said sawdust was an uncommon and
> unlikely fuel, to which Prof Mukunda's response was that any pulverised
fuel
> would do, and up to 50% of it could be wood chips or other pieces mixed
in,
> as long as the mass could be properly compacted and would not collapse
when
> the dowels that form the L-shaped draft hole are removed after compaction.
> At the start of the L, near the base of the stove, he had the same kind of
> air regulator control as described above.

(rwl): I hope your team is aware of the master's thesis work of Dr.
Priyadarshini Karve in Pune on this stove.

>
> One of our problems is going to be the variety of biomass fuels that
people
> want to use. No doubt there will be a different optimal design for each
such
> fuel: wood chips, wood sticks as you suggest, sawdust, dried leaves or
> groundnut shells, perhaps even briquettes as Prof Grover suggests. From
the
> amount of work that is going on around the world on the design of stoves I
> would guess it is hard enough designing a cheap and efficient stove that
is
> acceptable to the housewife for any one fuel: are we asking for too much
if
> we say that the same design, with minor adjustments, should work for more
> than one fuel? If we start with Prof Mukunda's basic design of stove for
> burning wood chips, could we not just remove the grating and use the same
> stove shell for compacted pulverised fuel with an L-shaped draft hole? Or
> replace the grating and burn a briquette which is placed on the grating?
The
> air supply regulation mechanism would be common to all.
>
(RWL): This is a great question - and I do not have a great answer. I
think that with a power source and controllable blower, one will have better
success with a range of fuel types - as one cannot have too much resistance
in the primary air path. One inserts a lot of resistance (pressure drop)
with any air flow controller, so one can't have too much in the fuel
container.

If you or Professor Grover or anyone know of any charcoal-making with
large briquettes with unusual air flow holes (as in some coal and charcoal
briquettes, I think this list would like to hear about that work.

When I have tried a deep layer of small wood pellets - no success (too
much resistance for a relatively short "chimney/combustion region", but
could get the right action with a thinner layer of bigger pellets. I have
tried cow dung without charcoaling success ever. Don't know the reason for
failure.

> We do realise that we are asking the housewife to have one stove for use
> with the Bachat cooker, and another for her other, regular cooking needs,
> such as frying or baking, for which the Bachat stove may be too small. All
> the more reason to have just the one design of Bachat stove, able to
> accommodate a range of biomass fuel types.
>
Perhaps you can still have two stoves if they are not too expensive. We
in the US feel cheated if we don't have at least four burners (plus many
other cooking devices).

> Incidentally, the flame size can be as small as you like. 7 cm dia we
would
> think is the outer limit. But the output needs to 0.5Kw. And on gas at
least
> we have found efficiencies improve if the tip of the flame just touches
the
> base of the cooker. On wood burning stoves I have no idea what would
happen
> as the flame level drops.
>
(rwl): This is my observation as well. On your last comment, I presume that
we agree that efficiency drops as the flame tip moves away from the cook
pot.

> If you have any further thoughts concerning any of this please let me know
> as we would like to discuss this in our next regular Research Team meeting
> scheduled for Wed 25 morning. And many thanks for getting us on the stoves
> list, the enlarged discussion is extremely useful. For example, we now
begin
> our work with an awareness of the range of fuels for which we should
> provide. We expect that as we progress the continuing dialogue with a
wider
> group will help us evaluate options that others have already explored and
> which we would otherwise waste time going into. We will keep you regularly
> posted as to what we are doing, and look forward to everyone's comments. I
> hope this 0.5Kw stove development can be an example of how progress can be
> speeded up by a process of wider invovlement and participation (is
mentoring
> a good word to describe that process?).
>
(rwl): Yours is a good example of what those of us in the
industrial world (unfortunately still a majority of the "stoves" list
membership) are looking for - as a way to both share our knowledge and to
learn from you. The whole sharing process is dependent on having the rapid
and cheap communication possible with the Internet.

Mentoring is not quite the right word since we all learn from each
other. Everyone can contribute with their own special knowledge. Being
able to do any big cooking job with only 0.5 kW is really remarkable

Please say good morning to all on your research team on the 25th.

Ron

> Regards,
>
> Shirish

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From Reedtb2 at cs.com Wed Apr 25 05:33:19 2001
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:52 2004
Subject: Forwarding Shirish on Bachat or REDI stove
Message-ID: <5f.143fb6ad.2817f3b0@cs.com>

Dear Ron and all:

In a message dated 4/22/01 7:44:09 PM Pacific Daylight Time,
ronallarson@qwest.net writes:

> think is the outer limit. But the output needs to 0.5Kw.

I think O.5 kW is much too small. Electric stoves in the U.S. have an
efficiency of about 60% and use a 2.5 or a 1.6 kW burner. Gas is less
efficient and is probably a 2 and 3 kW flame.

Reduced power extends the cooking time proportionally and results in much
greater heat loss from the pot during the cooking process.

I use a digital balance with a 5 g resolution to test various stoves. A
consumption of 10 g/min corresponds to 3 kW cooking power and will boil a
liter of water in 5-10 minutes, depending on the pot.

Comments?

TOM REED

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From Reedtb2 at cs.com Wed Apr 25 05:34:56 2001
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:52 2004
Subject: Gasification air flow for charcoal burning
Message-ID: <3d.ab16234.2817f3b5@cs.com>

Dear Jim and all

The air/fuel ratio of 6/1 by weight for charcoal comes from

C + 1/2 (O2 + 3.67 N2) ===> CO

In a message dated 4/22/01 5:27:24 PM Pacific Daylight Time,
enecon@ozemail.com.au writes:

<<
I have spent Easter making my first wood-fired gasifier, based on Tom
Reed's turbo stove (inverted downdraft gasifier), as posted on 1st March.
John Davies' work has also been helpful.

I can make nice flames burning the volatiles in the first phase, but am
having difficulty establishing a flame during the second phase when charcoal
is converted to CO. Probably I'm not getting enough primary air in.

My question to Tom is, what is the basis of your 6/1 air/fuel ratio to
convert charcoal to CO, when the charcoal is not flowing? I mean, if I put
in 6 parts of air to one of charcoal, what is to stop half the charcoal in
the gasifier converting to CO2, with no formation of CO? Surely there are
some other factors at work.

Regards,

Jim Bland >>

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BioEnergy Lists: Improved Biomass Cooking Stoves

April 2001 Biomass Cooking Stoves Archive