Eli led an informal rocket stove design and construction workshop at his Ancient Earth School of Natural Building in Freeland. The rocket stove was designed to warm the plaster-coated earthbag construction studio on his property, and the stove was about half completed over the weekend.
The primary advantages of rocket stoves: extremely high efficiency in generating heat for any given amount of wood fuel, and the wood is burned so hot and completely that smoke/pollutants are minimized considerably. They work well in cob and other natural buildings, but can really be used in any type of structure. There are numerous helpful books and online resources available describing the design and construction of rocket stoves.
Rocket stove combustion chamber base, with initial rough cob and brick thermal mass. Wood fuel is fed into the red elbow chamber protruding from the left top, the combustion chamber resides in the lower portion, and the exhaust and heat rises up through the opening on the right.
Hand mixing cob for the rocket stove; metal drum will be part of the stove heating surface
Cob, rocks, brick, and sand were all used to provide structure and thermal mass. This all later gets very smoothed out and organic looking, and is sealed with a nice plaster finish.
This chimney will be positioned inside the metal drum.
The rocket stove chimney was surrounded with wire mesh to hold vermiculite insulation.
The vermiculite insulation improves convection and air flow, which improves burning efficiency. Hot air rises up to the top through the chimney and then sinks down around its perimeter within an enclosing metal drum on all sides; it cools by radiating through the drum. From this point the exhaust will run through a warming bench (to be built on the right) and then vent outside the earth bag building.