Isegoria

Lesley Verbrugge came across references to rocket mass heaters while researching solar ovens, got sidetracked, bought a book on the subject, and ended up building one:

The Three T’s
In seeking a clean burn, think 3-Ts: Time, Temperature, Turbulence. The molecules of oxygen and of the combustion gases all need to be able to find each other as well as commingle. It’s like one of those huge country dances, where all the men line up on one wall, and all the women on the opposite one. When the music begins, everyone surges out onto the dance floor, looking for a partner of the opposite gender. For everyone to pair up, the tune needs to be prolonged (time), the music fast (temperature) and the dance rambunctious (that’s your turbulence).

So your combustion unit needs an insulated combustion chamber (in order to maintain the dancers at a high temperature), a tall enough heat riser that all the oxygen is used up (as the hot, lightweight dancers strut and spin their way up it), and a nonstreamlined profile to tumble the gases (shakin’ their boogilators, as they say). Hence the abrupt right-angle turns in a Rocket Stove’s interior.

Directing the Heat
There are variables which change where the heat is delivered. You can divide the heat that your stove generates according to your needs. There will be a trade-off between fast radiant heat and a long-lasting thermal battery. What heats up quickly — for example, a radiant barrel with little insulation around it — also cools down quickly. Conversely, what heats up slowly cools down slowly, so that the system with its pipe sunk several inches into a massive bed or couch provides warm comfort all night, hours after the fire has gone out. Decide well in advance what proportion you would like to have available for cooking, fast convective heat in your house, direct radiant heat that you can sit in front of, or contact heat that you sit, sprawl or lie on.

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