Winiarski Rocket Stove
The Winiarski Rocket Stove (Estufa Rocky)
One pound of dry wood releases about 8,600 btu's of energy when burned. Gasoline is only about twice as concentrated. It took a long time for the tree to grow. The daily amount of sunlight was captured and changed into chemical energy.
In fact, trees are very much like batteries, storing energy.
Wood is like a battery that has been storing energy for decades. The energy is concentrated and ready for use at any rate, depending on need. Also, this "battery" does not lose its charge while sitting, cannot spill acid on your pants, and usually smells good!
Burning wood or any biomass also has a great advantage over burning petroleum products. Trees absorb carbon dioxide while growing and release the same amount when burned. The tree reduces the amount of C02 in the atmosphere and then replaces it. Burning fossil fuels, made from plants millions of years old, can only increase the amount of atmospheric C02, since absorption done by the plants happened so long ago. Burning biomass does not increase the amount of C02 in the atmosphere in the same way that burning petroleum can.
The 54" in diameter conical concentrator focuses about 10 square feet of sunlight at the pot. Each square foot of earth receives between 200 to 300 btu's per hour on a sunny day. So, the conical cooker delivers about two to three thousand btu's per hour to the pot. That's approximately equal to the amount of energy that's held in a small bit of2 by 4 lumber only four inches long! The wood is very concentrated and we can burn it as quickly as we want. Direct solar energy is available at a fixed rate and can disappear behind clouds. If you've got it, wood is a powerful, convenient source of fuel. By using wood efficiently, people can cook food using branches and twigs instead of split logs. Gathering fallen branches can bring people firewood without killing the trees, if the rate of use matches the resource. The branches are already a handy size so people can be spared the labor of splitting logs as well. The trees continue to grow while people cook with wood.
Dr. Larry Winiarski's low mass Rocket stove has proven itself to be the most efficient cooking stove that we have used so far. It is far more efficient than high mass cooking stoves like the Lorena. We use Rocket type stoves now to cook, bake, heat water, warm houses, etc.
The Rocket stoves are based on an ingenious combination of principles: The combustion chamber is insulated in order to keep the fire hot (above 1,100 F.) to burn the wood more completely, reducing smoke which is uncombusted fuel.
The cooking stoves are low mass, robbing less heat from the pot. An insulated chimney creates a very strong draft which helps the wood to burn fiercely. It also makes the stove easier to light and to us;c. An insulated chimney has significantly more draft than an uninsulated chimney. The wood is burned at the tips and is shoved in towards the fire which controls the rate of burn, reducing smoke. The air/fuel mixture is regulated. A small opening is provided for incoming air. Too much air just cools the fire.
The incoming air is preheated, especially in a downdraft stove, which helps to keep the fire above 1,100 F. for complete combustion. A skirt surrounds the pot on all sides. A small gap between the skirt and the pot allows hot flue gases to rise up near the pot, greatly increasing heat transfer.
The flame hits the sides of the pot as well as the bottom. An insulated skirt reduces heat loss. Since the stove operates at very high temperatures, there is almost no smoke and it is possible to cook directly on top of the chimney. The flame, in contact with the pot, assures efficient heat transfer.
The "Guatamalan" Rocket stove is made up of six parts. Two of them are cut out of any five gallon metal container. This makes the external body of the stove. We've used soy sauce containers, paint buckets, etc. A short chimney (10"-12" is optimal) is made, in this example, from stove pipe. It's also possible to make the chimney from tin cans or more sturdy scrap metal. (A longer chimney will smoke less and may be preferable for that reason.)
Rocket Stove Plans: File:39346203-How-to-Build-A-Rocket-Stove-DIY-AT-HOME (1).pdf