Epic-greenhouse-rocket-mass-heater

Greenhouse heater


4 hour burn time, this just looks like an excellent idea in so many ways.

Damper, stainless riser, long burn times,  all of these things suggest a relatively low temperature ,smouldering fire with incomplete combustion.
It's still an innovative and useful build.

Interesting build, seems to be working well for them.   I foresee future issues, but for now whoo hoo !

It is essentially a batch box without the precise dimensional configuration which makes a batch box efficient/effective. They may have lucked out and gotten close enough for it to work well enough. Building one of these as an 8" or even 9" or 10" batch box could be an optimal solution. The bigger sizes may be able to support a down-and-back layout with the chimney next to the core for better draft. This could allow a full load of wood which would burn seriously hot and heat up the huge mass well. I would go with a masonry bell with access plate instead of the steel drum, so as not to give off too much instant radiated heat.