The Stoves Discussion list has been sharing information to improve cooking stoves since 1996. We use this site, to keep track of the many types of stoves, their designs, and the progress that has been made to improve them, and spread efficient cooking stoves in world wide.

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  • Kevin Chisholm, December 2005

    Dear All,

    Would you think it would be helpful if the Stoves List posed a "General Specification" for stoves?

    What is the maximum cost of the stove delivered to the "Customer", in $US equivalent?
    What is the maximum allowable cost for installation?

    Boiling water? Stewing? Frying? Baking?

  • AID Uganda April-May 2005, 10,000 Stoves Project, Ken Goyer June 2005

  • Dale Andreatta November 14, 2004, Updated January 17, 2005

    Executive Summary

  • Cookstove Efficiency Report, Dale Andreatta, January 2005

  • Juan Carlos Guzmán, Proleña Bolivia, July 7, 2004

    News from the alliance "Energy for the People" launched by Energética and ProLeña - Bolivia

  • Ceramics, Clay and Insulating Brick
    Biomass Cooking Stoves Discussions 2003

    Richard Boyt (May - September 2003)

    Ceramics for Stoves Part 1- Finding Clay
    Ceramics for Cookstoves 2: Testing Unfired (green) Clay Richard Boyt (May 2003)
    Ceramics for Cookstoves 3A: Test firing local clays- primitive kilns May 2003
    Ceramics for Cookstoves 3b: Test Firing Local Clays- Re-discovery of a "Natural" Kiln (June 2003)
    Ceramic for Stoves 4- Drying Formed Clay Shapes (September 2003)
    Ceramic for Stoves Part 5a- Making Samples for Testing

    Roberto Escardo (May 2003)
    Specific Thermal Resistance of Various Materials

    Dale Andreatta (April 2003)

    Heat loss from stoves: Thermal properties of insulative bricks Overall heat losses

    Dean Still Aprovecho (Mar 2003)

    Making Insulative Clay Combustion Chambers slide show
    The Effect of Material Choice on the Combustion Chamber of a Rocket Cooking Stove: Adobe, Common Brick, Vernacular Insulative Ceramic, and Guatemalan Floor Tile (Baldosa) Dean Still and Brad van Appel January 1, 2002

    Don O'Neal HELPS International (Feb 3 2003)
    Making Baldosa (Tile) for HELPS Stoves in Guatemala
    Damon Ogle Aprovecho Research Center (Jan 13 2003)
    Using Pumice to Make Lightweight Ceramics in El Salvador Damon Ogle, March 31, 2003

    Christa Roth and Christoph Messinger, Integrated Food Security Programme Mulanje, Malawi (2003)
    How to Make a Portable Clay Stove IFPS Malawi/GTZ ProBEC (Hedon)
    How to construct a kiln for clay stove firing Christa Roth, IFPS Malawi/GTZ ProBEC (February 2003)


    January 2003

    50% pumice

    Surface Coating Combustion Chamber Assembly

    Cutting HELPS Baldosa Assembly Malawi Portable Clay Stove

    Crispin Pemberton-Pigott

    There is an urgent need to find out how to make fire grates from clay in places like Ethiopia, Malawi and Rwanda where absolute cost is an issue.
    The easiest way to improve air quality and complete combustion is to provide preheated primary or secondary air the to the fire. Using clay/porcelain/ceramic materials would be best. There are some interesting things going on in ceramics. My son's ceramics instructor at Queen's U (Kingston Ont) had managed to make a ceramic material that was flexible like rubber. We want cheap, strong and thin and 'local' where possible.
    I would love to have a ceramic fire grate that would go into our all metal cooking stoves.

    Ron Larson

    1. I talked with Damon Ogle at the Seattle meeting (Jan 2003) about a materials problem that I would love to see several people work on beside myself (I'm in because my wife is a potter). That is adding a "best" glaze to the light weight ceramic blocks that Damon and others have been preparing.. We discussed one that would be reflective - but it should also have the right strength and shrinkage properties so as to add to the overall strength of the brick. (And fuse at the right temperature.) There are certain coating materials in the solar collector business that are typically high absorptance and low emittance - we want just the opposite.

    2. One can buy (at a pretty high price) refractory cements - that look like they might be manufacturable in developing countries - and offer nice patching and construction alternatives.

    3. We have had differences of opinion on using hoods vs. chimneys. The former would only have to satisfy quite minimal temperatures - but need to be appreciably larger than chimneys. Perhaps there are some foil products that your class/student(s) could work on - with light frames.

    4. On the other side is the chimney material problem. Maybe cast concrete? (over a wire mesh?) certain steels? ceramics? The key problem is cost (but lifetime has to be good as well). Can we do this out of used coca cola cans?

    5. There has been a lot of discussion about the thermal flexing and durability of the plancha (top cooking surface). Getting a better handle on this would be a big help in Central America and Ethiopia - thickness, best material, ways to economically strengthen/support, etc. I wonder if there is a coating that would help? A composite material? (cost-prohibitive?)

    Dean Still

    The most important thing that we now need to do is to determine how to make best bricks (insulative, refractory, durable) from pumice and 15% clay. Can we make pumice bricks that are as good as the perlite bricks? Pumice changes color( to red)and shrinks around 900 to 950C or so. The bricks need to be fired lower than this so that the pumice remains full of air.

    If you can find light weight pumice this would be valuable work with immediate applications in Central America. I hope that your students can make pumice bricks and compare them to perlite and sawdust bricks.

    See: Rocket Stove Design Guide

    Tom Miles

    Do we have a listing of materials and their characteristics? Dean was using Thermal Ceramics TR 19
    for the prototypes he was demonstrating. I don't remember the thickness. How does that compare with the 50% pumice, 50% clay-organic or other materials? Can Rogerio, GTZ or others supply samples of materials they have fired for their stoves in mass production?

    A question for the group: what about thermal cycling - would a test of accelerated aging of the ceramic or insulating materials be useful?

  • Dean Still, Lanny Hensen, Peter Scott June 2002

  • Dean Still and Brad van Appel, Aprovecho Research Center, January 1, 2002

    The Effect of Material Choice on the Combustion Chamber of a Rocket Cooking Stove: Adobe, Common Brick, Vernacular Insulative Ceramic, and Guatemalan Floor Tile (Baldosa)

    The Search for Vernacular Refractory Materials

    Multiple tests of the Lorena stove beginning in 1983 at the Aprovecho Research Center have shown that placing thermal mass near the fire has a negative effect on the responsiveness and fuel efficiency of a cooking stove. In 1996, Leoni Mvungi built a Rocket stove from earth, sand, and clay that was a replica of a low mass Rocket consisting of metal chimney parts. His version weighed hundreds of pounds even though the Rocket internal chimney was only eleven inches high. Tests of a low mass sheet metal version scored around 30% fuel efficiency. But the best result achieved by the Mvungi stove was around 15%.

    Building Rocket stoves from sand and clay showed little promise of improving on the three stone fire which was scoring around 18% in repeated boiling tests performed by Jim Kness and Dean Still (1994). Unfortunately, metal stove parts also have a major drawback in that the high heat in the combustion chamber quickly destroys thin metal. Consultants were in agreement that a good stove should last for years without requiring maintenance. Replacing metal parts as they wear out was not considered a viable solution.

    A women's co-operative in Honduras (Nueva Esperansa) makes ceramic stove parts that have a reputation for working well in stoves. Aprovecho consultants Mike Hatfield and Peter Scott contracted with this group to produce combustion chambers for the Dona Justa plancha stoves that they helped to design. This material seemed to work well and, in fact, the Rocket elbow made by Nueva Esperansa has been successful in Honduras and Nicaragua. It is difficult, however, to deliver the fragile combustion chambers without breaking them. Also they are relatively expensive, costing about eight dollars each.

    Don O'Neal (HELPS International) and Dr. Larry Winiarski have shown that cast iron combustion chambers, which do last, also have problems. Tests showed that the very conductive cast iron made the fire hard to start. In fact, a group of indigenous Guatemalan women stove testers living in Santa Avelina were unhappy with the expensive cast iron combustion chamber and asked for it to be replaced. They wanted a more responsive stove that started quickly, and quickly cooked food in the morning. Don and Larry eventually found an alternative material: an inexpensive Guatemalan ceramic floor tile (called a baldosa in Spanish) which seemed to function well when cut up to make the walls of the Rocket combustion chamber. The baldosa was about an inch thick so the combustion chamber only weighed eighteen and a half pounds. Like all Rocket combustion chambers it is surrounded by insulation, either wood ash or pumice rock.

    The baldosa tile has done well in test stoves. It seems to be durable, lasting a year so far, and the group of testers from Santa Avelina reported that their stoves are much improved. The ceramic material made the stove much quicker to heat up. The women approved the improved stove for general dissemination to neighbors and other villages. The HELPS molded griddle stove now uses a preformed ceramic combustion chamber made by a local baldosa manufacturer. Unfortunately, all baldosa are not equally resistant to heat and it's important to test tiles before using them in stoves.

    Appreciating that ceramic seemed a promising material for Rocket combustion chambers, Ken Goyer, an Aprovecho Board Member and consultant, spent a year, 2000-2001, testing ceramic mixes. His research resulted in a vernacular insulative ceramic material (VIC) that is refractory, insulative and can be home made. Six bricks made from this material combine to make a complete Rocket combustion chamber. Making the chamber from separate bricks has resulted in a greatly reduced tendency to crack. The bricks have held up so far in durability tests and they seem to create a very active fire.

    The purpose of this paper is to describe the results of experiments involving same sized brick combustion chambers made from adobe, the insulative ceramic mix and common ceramic brick material. All bricks shared the same dimensions. Six bricks (11 ½" high by 2 ½" thick) made up a hexagonal cylinder surrounding a four inch in diameter chimney. Sticks of wood entered the bottom of the chimney through a hole sawn in the bricks. A combustion chamber made to similar dimensions was constructed using baldosa tile bought in Guatemala. Vermiculite filled in around the baldosa creating a combustion chamber with approximately the same dimensions as the brick stoves.

    Protocols for Standard Stove Tests Using PICO Software

  • High Performance Combustion with a Simple Technology

    Nov.15 2000

    Presented to the International Conference on Biomass-based Fuels and Cooking Systems 2000
    Nov 20-24, 2000 Pune, India
    Pictures from the conference.

  • Alex English, Sept 27, 2000

    Bigtop Gasifier

  • This afternoon I tested a scaled up version of the venturi burner.
    The idea being to produce charcoal on a "viable" scale without the
    high production of polluting gasses.

    Much of this chimney flare was built out of heavy steel because that is what was available. There is no reason why the whole chimney couldn't be made out of sheet metal stove pipe.

  • T. B. Reed and Ron Larson

    *Presented at the "Developments in Thermochemical Biomass Conversion" Conference, Banff, Canada, 20-24 May, 1996.

    Introduction -

    A.The Problem

    Since the beginning of civilization wood and biomass have been used for cooking. Over 2 billion people cook badly on inefficient wood stoves that waste wood, cause health problems and destroy the forest. Electricity, gas or liquid fuels are preferred for cooking - when they can be obtained, but they depend on having a suitable infrastructure and are often not available in developing countries. In the last few decades, many improved wood stoves have been developed (the Chula, the Hiko, the Maendeleo, the Kuni Mbili, etc.), but the new wood stoves are often more difficult to manufacture, often more heat goes to the stove than to the food, and they do not offer good control of cooking rate. They are not always accepted by the cooks for whom they are developed.[1] Because of the problems of wood cooking, people often cook over charcoal. However, charcoal manufacture is very wasteful of energy and very polluting, so the problems of the wood stove are externalized but not solved.


    Gas is preferred for cooking wherever it is available. Gas can be made from wood and biomass in gasifiers developed in this century, but these gasifiers are generally too big for home use. A downdraft stove for domestic cooking is now being manufactured in China.[2] We have developed a new "inverted downdraft gasifier" stove shown in Fig. 1. It operates using only natural convection. The rate of gas production and heating is controlled by the primary air supply to the gasifier. As an option, the gasifier can make charcoal with a 20-25% yield. The wood-gas stove consists of an "inverted downdraft gasifier" (shown in Fig. 2) plus a burner to mix air and gas and burn cleanly (Fig. 3). These sections are discussed below. The stove has been started and operated indoors with no exhaust fans and no odor of burning wood. However, we believe that there is still much work to be done in optimizing the stove for various fuels, adapting it to various cooking situations and developing other uses. For that reason we are publishing our preliminary results and hope that others will help adapt these principles to improve world cooking and wood conservation.

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