Re: The Mayon Turbo Stove

["Paul S. Anderson" <psanders@ilstu.edu>]

Dear REAPers  (if that is an appropriate and respectful name.)

I have read all and have printed all of the site.  You have a great 
product.  Your manufacturing abilities are impressive.  Your pictures and 
descriptions are great and are a model for others to emulate.

There are several similarities of your Mayon stove with the gasifier but 
yet you are not actually a gasifier of the top-lighted, up-draft type that 
I am working on for the Juntos stove.   Your big advantage is the ability 
to load extra fuel from the top and continue your burn.  Second "advantage" 
(to some) is that you burn fully to ash, meaning you do NOT produce 
charcoal that could be removed; your stove consumes the char, yielding heat 
energy.  One disadvantage of that is that you metal will become hotter, and 
therefore your stove must be of "substantial" metal and not of "tincanium".

We must all congratulate you on bringing the cost of your stove down to the 
US$7 mark.

Via the Stoves list serve I will keep you informed of some ideas 
appropriate (?) for what you are doing.

Only if I am incorrect, please comment:  I believe that your outer cone 
(what you call the "main drum" in the list of Materials) is a hopper in 
which rice hulls are held and then scooped from there and placed into the 
inner-most circular opening.  (nice way to minimize spilling of a fine 
substance like rice hulls.)   But since it does not get hot (except for the 
lower part with the primary air holes), why not incorporate the air holes 
into the inner units, and then just have a thin sheet-metal cone to be the 
hopper for the rice hulls?  This would greatly reduce your materials costs.

Can you please comment further on your experiences with the "supplementary 
fuels" (in the "how2 use" document) in relation to your 
stove.  Specifically about coconut husks and corn cobs as being 
"longer,slower burning".  but please tell me (us) about heat generation and 
need to tend or not tend the fire more.

I for one look forward to working with you.  Are you willing to do 
experiments via e-mail?

Paul

At 05:48 PM 2/19/02 -0500, RSamson@reap-canada.com wrote:
>Dear Stovers
>
>You may be interested in an ongoing rice hull cooker stove improvement
>program REAP has been involved in with partner organizations in the
>Philippines.  Detailed information on how to use and build the Mayon
>Turbo Stove is now on our WEB site at:
>
>www.reap-canada.com
>
>Please fund below a summary of the projects background and development.
>
>Like many developing countries, the Philippines has a growing population
>and increasing rural poverty, and cooking fuels are becoming
>increasingly scarce. REAP recently completed a report for NREL on
>“Strategies for Enhancing Biomass Energy Utilization in the Philippines”
>and one of the most promising options identified was to utilize rice
>hulls as a low cost domestic cooking fuel source. There are more than
>1.5 million tonnes of recoverable rice hulls in the Philippines which
>could be used as cooking fuel by more than 1 million families. Using
>rice hull locally in low cost cookers seemed the ideal way to utilize
>the resource as it is widely dispersed and of a bulky nature.  Rice hull
>also has the natural advantage of being of a uniform and small size.
>These characteristics make it relatively easy to design an efficient
>combustion system for household cooking in comparison to burning with
>wood or other crop residues.
>
>In 2001, REAP acquired a 3 year funding program from the Canadian
>International Development Agency to introduce an improved rice hull
>stove into approximately 10,000 households in the Western Visayas region
>of the Philippines. To improve the stove, we accessed all the major rice
>hull stoves available in the Philippines including versions from the
>International Rice Research Institute (IRRI), Philrice, the Central
>Philippine University (CPU) and a version of the Lo-Trau model developed
>in Vietnam. Some of these stoves were superior to others but all
>suffered from  from one or several deficiencies including: incomplete
>combustion, excess air, uncontrollable fuelbed fires, high rice hull
>consumption and being overly expensive for rural peasants to purchase.
>We needed to build a stove for under (US) $7.50, as this  represented
>one weeks salary in rural areas of the Western Visayas. Peasants also
>were  used to buying charcoal and firewood stoves made from clay that
>sell for about (US)$ 0.50.
>
>We decided to work with the Lo-Trau model because of its relatively low
>cost and simple basic design. With our partner organizations, PDG and
>MASIPAG, we streamlined production improvements to manufacture the stove
>to get production costs down to  (US)$7 per stove. However, we observed
>that the stoves we were introducing to communities were experiencing
>problems of incomplete combustion and required constant maintenance and
>tapping.  We made some initial combustion improvements to the stove by
>lengthening the frustrum (the center cone) from 5 to 7 inches (which
>also shrank the cone top and concentrated the flame under the pot). We
>also drilled secondary air holes, 2 to 3 from the top of the cone. To
>minimize fuelbed fires, we eliminated one of four rows of holes at the
>base of the fuel bin to reduce upward airflow through the fuel bin.
>These changes improved the stove, but the flame remained excessively
>smoky and the stove required regular tapping (although this was reduced)
>to maintain combustion. The CPU stove we tested had a single air vent
>pipe through the bottom of the ashpan, which appeared to help reduce
>smoke events. We decided to experiment with different sized pipes to
>determine a level of air that would be adequate but not excessive. We
>noticed that the single pipe caused a blue flame in the center of the
>cone. However, surrounding this oxygen source, the flame was still an
>orange-yellow colour. We realized we needed more air mixing in the cone
>as we perceived there were still oxygen dead spots that led to
>incomplete combustion of the gases. One option we tested was twin air
>pipes of 1 inch diameter to increase turbulence inside the cone. They
>ended up creating vortexes in the flames and appeared to slow the rate
>of air flow out of the cone (which was excessive in the centre with the
>single large air pipe). The result of the twin air injectors was that
>after 3-5 minutes, a blue or nearly colourless flame was present
>throughout the cone. Maintenance of the stove also was reduced, tapping
>of the stove was only required after 10-12 minutes to maintain the stove
>flame.  However, we still experienced some smoke events after ten
>minutes of burning when the rice hull turned to ash and reduced airflow
>from the holes at the base of the fuel bin. We decided to increase the
>size of the 10 secondary air vents from ¼ to 3/8 inch. After this
>modification, we experienced no more smoke events due to oxygen
>problems. Smoke events only occurred when the flame was going out due to
>lack of fuel. This occurred generally when the fuel bed turned grey from
>the hulls being completely burnt out. Simply tapping to introduce more
>fuel, about every 10 minutes maintained the flame.  The new model also
>has been found to be easier to start, and produces less smoke upon
>termination. Essentially we believe now the stove has a near perfect air
>situation. There appears to be no excess air and no oxygen deficient
>areas of the cone, or oxygen deficient periods during the entire burn
>cycle. When new fuel is added, smoke infrequently occurs and a clean
>burning flame returns rapidly. Clean combustion occurs as the new design
>appears to increase the gases residence time in the inner cone and
>exposes them to higher temperatures. The rice hull ash falling out is
>now of a whitish grey colour. The changing nature of the airflow through
>the fuel bed (as the relatively porous hull turns to ash) is dealt with
>through the twin air pipes and secondary air at the top of the inner
>cone. The most important new design improvement appears to be the twin
>air injectors that create a swirling and mixing action. Older stoves in
>communities are now being retrofitting with the twin pipes.
>
>We have had favorable feedback thus far from communities using the
>stove. Households are experiencing reductions in rice hull fuel
>requirements, less maintenance and less smoke. The main activity we are
>now examining is to build a smaller stove with a 6 inch diameter
>fuelbed. The 7” diameter fuelbed model now appears to have excessive
>heat output for smaller pots of rice because of more complete combustion
>of the rice hulls and gases, and better control of the air flow. The
>project is still in its first year and we are currently producing and
>marketing approximately 350 stoves per month. Savings appear
>considerable for low income rural families purchasing firewood, charcoal
>and LPG. A user survey found cooking with the Mayon Turbo reduces the
>annualized cooking cost (annual stove and purchased fuel cost) to only
>(US) $5.20 per year in Negros, a  91-95% compared to purchasing the
>aforementioned fuels.
>
>A line drawing and instructions on how to build and use the Mayon Turbo
>Stove can be found at www.reap-canada.com. We would be most willing to
>work with other groups who are interested in building the improved stove
>in other rice producing nations.
>
>Good luck trying the stove and we look forward to your feedback.
>
>Trevor Helwig, Claudia Ho Lem and Roger Samson
>
>Resource Efficient Agricultural Production-Canada
>Box 125, Maison Glenaladale,
>Ste Anne de Bellevue,
>Quebec, CANADA
>H9X 3V9
>WWW.REAP-CANADA.COM
>Tel. (514) 398-7743
>Fax (514) 398-7972
>
>"Creating ecological energy, fibre and food production systems"
>
>
>
>
>
>
>-
>Stoves List Archives and Website:
>http://www.crest.org/discussion/stoves/200202/
>http://crest.org/discussiongroups/resources/stoves/ (Under construction)
>http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
>Stoves List Moderators:
>Ron Larson, ronallarson@qwest.net
>Alex English, english@adan.kingston.net
>Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
>List-Post: <mailto:stoves@crest.org>
>List-Help: <mailto:stoves-help@crest.org>
>List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
>List-Subscribe: <mailto:stoves-subscribe@crest.org>
>
>Sponsor the Stoves List: http://www.crest.org/discuss3.html
>-
>Other Biomass Stoves Events and Information:
>http://www.bioenergy2002.org
>http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
>http://www.crest.org/articles/static/1/1011975339_7.html Gasification
>http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
>For information about CHAMBERS STOVES
>http://www.ikweb.com/enuff/public_html/Chamber.htm

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


-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/200202/
http://crest.org/discussiongroups/resources/stoves/ (Under construction)
http://www.ikweb.com/enuff/public_html/Stoves.html (Original)

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com

List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>

Sponsor the Stoves List: http://www.crest.org/discuss3.html
-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm