[Stoves] A hypothesis for a more efficient stove

[David G. LeVine]

I have been a lurker here and on the gasification lists for a while, and there seems to be a potential win by combining both technologies.

A Rocket stove has been reported to give off excess CO.

Three stone fires tend to burn the excess CO and give better efficiency due to the small blue flames, but not any better than the Rocket.

Hypothesis:
A Rocket stove with a heated secondary air supply might be more efficient.

How to test this:
Make a steel can fuel container with limited air from below.  Put it in the Rocket chamber and light the fuel.  Restrict the air coming around the can until the gases do not fully burn, then increase slowly for best heat output.

Why would this work:
Volatile components of the burning biomass vaporize, by using a "tin" can the gasses can be contained and protected from dilution which would prevent it from burning.  Some heat will go to heating the can, this can be used to pull fresh air in and preheat it (cold air is NOT a way to enhance efficiency.)  When the gasses combine with the heated air near the pot bottom it will burn dumping its heat load closer to the pot, possibly at a point where the flame best intersects the pot  (again, lower losses due to a controlled burning zone.)  Since the losses to the can are not transferred to the outside world, they are 
reduced.  When all volatiles are gone, charcoal remains and can be used to keep the pot warm after the initial cook fire goes out.

This is a traditional TLUD burner except it has no fan and it preheats the secondary air.

Comments on this (obviously) more complex hypothesis?

Also, Lanny Henson has been promoting his TLSD (Top Lit Side Draft) and TLSS (Top Lit Side Supply) burners which may be a way to resolve the issue of the "inner" burner (i.e. "tin" can.)  His site http://www.lanny.us/popup.html is really quite interesting.

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David LeVine
Nashua, NH, USA