toaster slot briquette stove liner with grate
toaster slot briquette stove liner with door flaps
toaster slot briquette stove liner with door flaps front
toaster slot briquette stove front one door flap open
toaster slot briquette stove doors open

I have been designing some briquette burning stoves for El Fuego del Sol, which is making square fuel briquettes from paper, cardboard, and sawdust in Port au Prince, Haiti:
The stoves are loosely based on rocket stove principles. My latest stove is inspired by the toaster. Briquettes are like thick pieces of bread. For good combustion they need to be surrounded by air and slightly separated from each other and the liner wall. This design holds 4 briquettes in two vertical slots of expanded stainless steel. As they burn down, new briquettes are added through insulated swinging door flaps.
Wrapping new briquettes in a sheet of paper before insertion ensures quick ignition and minimal smoke production.
Air comes in the front and bottom and can get to all sides of the briquettes. The insulated doors block much of the radiant heat from the upper briquettes from escaping out the front and keep briquettes from rolling out of the stove.
The liner will be surrounded with insulating bricks and have a galvanized steel outer shell. There will be a pot support frame and sheet metal pot skirt at the top.
The concept should also work well with round briquettes and dung fuel.

Mike Mahowald,

An Efficient Cookstove with two burners, two heating surfaces and a small oven:

This stove is designed to work with Vetiver Grass, they also have plans to encourage small scale productions of Vetiver grass straw pellets for use by the wider Haitian community.

How they'd like to encourage grass straw pellet production

Dear all,

For over two years we have been telling people that in two weeks or so we hope to have the mud Rocket Stove website updated. It finally happened. Flip has worked countless hours on this. This morning she shouted out, "The baby is born!"

Thanks to Larry Winiarski for all the mentoring and watching over us. Without Larry and the Good Lord this would have never happened. http://www.rechoroket.com/Home.html

Happy New Year,
Jon and Flip

I was finally able to complete my tractor jack briquette press on a recent trip to Haiti. I started it in the spring but had to load it into a shipping container in May before I could complete and test it. It uses a 3 1/2 ton (3.2 tonne) 48" (122cm) tractor jack. About 30" (76cm) pressing cylinder, 3" (76mm) diameter PVC . Two 3/4" (19mm) threaded rods for tensile members. 4' x 6" (10cm x 15cm) rectangular steel tubing base. Shouldered hole in bottom to hold cylinder base while allowing briquette ejection. 4" x 4" (10cm x 10cm) square steel tubing top. Wood frame. Removable steel plate covers ejection hole for pressing.
The long stroke allows for production of multiple briquettes at once.
The current design produces pucks. Holey briquettes are possible with some modifications.

On a recent trip to Haiti I was finally able to construct my CharBowl(tm) charcoal stove. It uses two nested stainless steel bowls (5 quart and 8 quart (4.7 liters and 7.6 liters))for durability and reflectivity with castable insulating refractory between them to reduce conductive heat losses. It has a 6.5" (16.5cm) dia cast iron grate for durability. It has a secondary air pipe to reduce CO emissions and increase heat output. The secondary air outlet pipe is 3/8" (10 mm) nominal (ID 0.493" 12.5mm; OD 0.675", 17mm) black iron with a Tee fitting on top to keep charcoal from dropping into it. 3/4" NC 10 (19mm 2.5) machine threads were cut over the pipe threads. This allowed the use of a split nut and flat washer inside and outside the bowls to hold the bowls together. The elbow is 3/8" to 1/2" . The inlet pipe is nominal 1/2" iron (ID 0.622" 16mm; OD 0.84", 21mm). The bowls sit on a stock pot base for stability and primary air control. (I couldn't get my hands on the stainless pot I really wanted to use for the base. I'm planning to build another with such a base now that I'm back in the States.)
I hope to get some testing done on my second prototype.
It can be used as the base of a TChar stove.

Una reciente evaluación realizada por los refugiados de la Mujer de la Comisión en Haití constató que el precio del carbón ha aumentado en un 40% (CMR y el PMA 2010). Cómo ayudar a las poblaciones sujetas a desarrollar la capacidad de producción de biocombustibles líquidos puede ofrecer una importante solución a la pobreza energética en las comunidades desplazadas de Haití y contribuir a su desarrollo a largo plazo de la autosuficiencia energética.

Proyecto Gaia ha estado trabajando en Haití para promover el etanol y la Estufa CleanCook - una estufa a base de alcohol - como alternativa a las estufas que queman biomasa sólida (es decir, madera, carbón vegetal y briquetas.) El etanol es tan limpia como gas licuado de petróleo, más barata que el carbón, más seguro que el queroseno y tiene más potencial que las briquetas de basura. En África, el Proyecto Gaia ha acumulado más de 2 millones de días de cocinar con la estufa CleanCook sin un solo accidente de cierta importancia.

La pregunta más común que aparezcan durante nuestras conversaciones con los responsables políticos y los empresarios sociales es: ** "¿El suministro de etanol, sea sostenible? Y ¿dónde estaría la oferta provienen de donaciones después tocaban a su fin? "**

Esta es la pregunta clave de la sostenibilidad y la razón de por qué estamos tan interesados en Haití. No sólo fue Haití una vez al líder productor de azúcar y una destilería de etanol de bebidas para la exportación, así como el mercado local, pero también Haití existe en las rutas comerciales durante el cual miles de millones de litros de etanol cada año el flujo de camino a un mercado de combustibles en el los Estados Unidos. Este etanol, sobre todo de Brasil, generalmente el precio más competitivo en el mercado de materias primas, proporcionará una fuente de combustible para Haití-más barato que el petróleo-como Haití acumula su propia producción local (Etiopía Petróleo de datos empresariales). De hecho, el Gobierno brasileño se ha comprometido a donar más de 100.000 litros y un litros otros 400.000 en los próximos dos años.

Christa Roth and Christoph Messinger, August 2010

Existing Charcoal Stove

Existing Charcoal StoveImproved Charcoal Stove

Improved Charcoal Stove

Improving the Charcoal Stove for Haiti, Stove Camp 2010 (see the Stove Camp Summary for challenge details)

Main points mentioned at the end of the Stove Camp Workshop

  1. We need a high turn down ratio.

    To bring water and foods fast to the boil, we need high power in the heat-up phase.
    However, thereafter we commonly need low power for simmering. The stove
    therefore needs to offer the opportunity to turn down the power output drastically.

    1. Regulation of primary air supply (e.g. closing door)
    2. The gap between pot and charcoal is increasing over cooking time (shape of char container provides more depth = increased gap to the char)
    3. c) The amount of char available at the end of cooking is reducing (conical shape of char container = less char over time available)
  2. We need to reduce heat losses to the bottom and to the side of the stove.

    A char container radiates heat to all sides – not just to the pot. To reduce the amount
    of char used, it is important to reduce the heat losses to the other directions.

    1. Bottom of stove: rebounding plate (with holes) in between primary air supply
    2. intake and charcoal container. Thus primary air is channeled through the
    3. heated rebounding plate, taking some heat back into the char container.
    4. Side of the stove: double wall with air in between for insulation.
  3. We need to maximize heat harvest from a given amount of charcoal.

    Charcoal burning is mainly influenced by the amount of air available in the char

    1. A vertical spacer in the center of the charcoal container (Lanny Henson’s pig tail”) seemed to increase the availability of air for charcoal combustion.
    2. Additional draft (e.g. forced air) may increase heat generation per time unit. However, this may also increase CO emissions and reduce efficiency of char use.
    3. Secondary air to burn off the CO in a gap between the charcoal and the pot may provide additional heat. However, for this to be beneficial it may not impact on the surface area available for direct radiation from the charcoal to the pot and should not cool down the air in the gap (well preheated secondary air).
  4. We need to maximise heat transfer to the pot.

    Generating as much heat as possible out of a given amount of charcoal is one step.
    But another important step is to make sure that most of this heat actually is
    transferred into the cooking pot.

    1. “Sunken pot” concept seems to provide best results in terms of heat transfer (Henson stove). Unfortunately, in real life this might not be possible in many work environments.
    2. Best heat transfer is NOT achieved if the pot rests on the char. Optimum is about 1inch away from the char, not closer than that. For Simmer, this could increase to 2-3 inches.
    3. A skirt is highly important to shield the gap area between the pot and the char against the influence of wind. The gap between pot and skirt should bedetermined.

Christa’s Summary of the stove camp

Observation and necessary action Derived Design Principles
Charcoal radiates heat to all
sides: as much can radiate
towards the bottom of the stoves
as can radiate upwards towards
the pot.

Avoid loss of radiating and
conducting heat from charcoal
that is not directed towards the

  • Add space between the charcoal grate and other stove parts: Lift the charcoal grate slightly off the bottom of the stove and increase the space to the sides of the stove.
  • Limit the places where the hot grate can conduct heat to other stove parts.
  • Add a deflector plate between charcoal chamber and the stove bottom to radiate heat back upwards.
  • Insulate the stove bottom to prevent heat loss through the bottom.
  • Insulate sides of the stove.
  • Regain heat through air circulation (air cooling of stove) by passing air through heated stove parts thus preheating air entering the combustion system. This can be by passing primary air through the deflector plate below the grate and/or secondary air through a gap between double side walls of the stove.
Charcoal combusts in function of the available oxygen. Thus heat generation is a function of
air supply to the charcoal grate.

Action: get the right amount of air to the charcoal grate. To little will choke the combustion, too much will cool the flue gases.

If power of the stove is too low, increase air supply by

  • making more holes in the grate.
  • adding a ‘Henson pig-tail’ vertical air-pass through the charcoal bed.

Do not pile the charcoal up too high, as this will restrict air flow through the charcoal bed (this is influenced as well by the shape and particle size of the charcoal chunks).

The combustion of charcoal goes from oxidizing C to CO, then in
a subsequent step from CO to CO2.

CO is a toxic gas and has still considerable energy value. Ensuring a complete combustion
will increase energy output and reduce toxic emissions.
Action: avoid CO emissions.

Charcoal radiates heat but there is also considerable convection of hot flue gases.
Optimize transfer of created heat into the pot.
Avoid obstructions between the radiating charcoal bed and the bottom of the pot (increase
the view factor of the charcoal seeing the pot).

Patrick Bringardner, Project Gaia, August, 2010

A recent assessment conducted by the Women’s Refugee Commission in Haiti found that the price of charcoal has risen by 40% (WRC and WFP 2010). Helping subject populations to develop the capacity to produce liquid biofuels may offer one important solution to energy poverty in Haiti’s displaced communities and contribute to its long term development of energy self-sufficiency.

Clean Cook StoveClean Cook Stove

Project Gaia has been working in Haiti to promote ethanol and the CleanCook Stove - an alcohol based stove - as an alternative to stoves that burn solid biomass (i.e. wood, charcoal, and briquettes.) Ethanol is as clean as LPG, cheaper than charcoal, safer than kerosene and has greater potential than trash briquettes. In Africa, Project Gaia has accumulated over 2 million days of cooking with the CleanCook Stove without a single accident of any significance.

The most common question which arises during our discussions with policy makers and social entrepreneurs is:** “Would the supply of ethanol be sustainable? And where would the supply come from after donations were at an end?” **

This is the key sustainability question and the reason why we are so interested in Haiti. Not only was Haiti once a leading sugar producer and a distiller of beverage ethanol for export as well as the local market, but also Haiti exists on trade routes over which billions of liters of ethanol flow each year on their way to a fuel market in the United States. This ethanol, mostly from Brazil, generally the most competitively priced in the commodity market, will provide a source of fuel for Haiti—cheaper than kerosene—as Haiti builds up its own local production (Ethiopian Petroleum Enterprise Data). In fact, the Brazilian Government has pledged to donate over 100,000 liters and an additional 400,000 liters over the next two years.

Haiti was once a powerful agricultural economy, producing for its own needs. In 1983 Haiti harvested 70,000 hectares of sugarcane. Today it harvests less than 17,000 hectares (Figure 1: Decline in Sugar Cane Production (UN Data World Statistics Pocketbook)). Haiti’s dependence on export markets has increased its vulnerability through its reliance on basic sustenance items it once produced locally. Today it supplements most of its own food staples with imports – a precarious equilibrium. Other than charcoal, most other fuels are imported.

In regards to domestic ethanol production, Haitians are no strangers to the distillation of alcohol. Thousands of small mills and distilleries make beverage-grade ethanol in Haiti. In Léogâne alone, over 200 small distilleries were in operation before the earthquake (ESMAP 2007). Many of the existing distilleries in Haiti, those shut down or still in operation, could be repaired and refurbished to produce fuel grade ethanol. Project Gaia has been in contact with an operating distillery in the vicinity of Léogâne that could upgrade to produce hydrous ethanol fuel and put this fuel into the market in a matter of months.

Many opportunities exist for small scale distilleries. In Haiti, some small ethanol enterprises are already active thus presenting the perfect opportunity for value chain development through the support of SMEs (small and medium enterprises). The number of sugarcane transformation workshops throughout the country is an estimated 5,612 (ESMAP 2007)

Haitians rightly believe that Haiti’s way back from dependency is through agriculture and a renewed attention to domestic needs and markets. Therefore, by developing ethanol as a household fuel, it will profoundly benefit Haiti because Haitians can produce biofuels from their own agricultural crops. Moreover, Haitian families will finally have access to cooking fuel that is safe, clean, affordable and sustainable. A way back to economic - and human - health for Haiti is to produce ethanol for its domestic energy market.

Nathaniel Mulcahy May, 2010

Nat Mulcahy and the World Stove Haiti project was nicely profiled on the web site The Charcoal Project. Read the full article A Man, a Stove, a Mission

From the Charcoal Project article:
"Mulcahy is the founder of WorldStove, a small Italy and U.S.-based company that manufactures a range of energy efficient, biomass-burning cookstoves. The company operates two business lines. One sells pricey cookstoves and barbeque grills for the outdoor/camping crowd in industrialized societies. The other line of stoves, the research of which is funded by the former, helps bring energy efficient cookstoves and locally owned businesses that produce them, to the oceans of energy poor people around the world who don’t have access to modern fuels like LPG and electricity.

"Mulcahy has recently returned from Haiti where he spent two months setting the foundations for a sustained long-term plan to alleviate the country’s heavy dependence on the inefficient combustion of the wood and charcoal. President Bill Clinton, the UN Special Envoy to Haiti, highlighted WorldStove’s remarkable and quick work in Haiti in a recent Earth Day address."

The World Stove has also been profiled (by Kelpie Wilson) on the Huffington Post, read WorldStove: Transforming Haiti and the World

And there are some great videos on YouTube, including this one:


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