Ken Jackson : I feel like a dummy, but I did a Due-diligence Google Search, ( English only ) before I came here and am still no wiser! What is a HAHAS?
Anyway, welcome to permies.com ( and our sister site richsoil.com ) and a Warm Welcome to the Rocket Stoves and
Wood Heater Forum Threads ! This is exactly the kind of out
of the box thinking that we really need to grow ! There are a few problems with your build but many people would like a simple outside building to contain their
wood stove so we
all look at new ideas carefully for adaptation, someone may see something I don't!
The newest innovations of the
Rocket Mass Heater R.M.H. burn freaky hot giving them their Great Efficiency, after the combustion chamber the hot Exhaust gases must travel up
the very well insulated Internal Chimney/ Heat Riser where the gases slam into the inside top of the 55 gal metal drum. Seen from the side the swirling gases would look like
Rams Horns. Seen from on top looking down if you could - the gases flow in a toroid or doughnut shape, here they start radiating off large amounts of heat
energy, cooling and
falling down the outside of the internal chimney / Heat Riser, still inside the skin of the barrel, and still radiating Gobs of heat !
It is important that there is a great difference in temperatures between the inside of the Heat Riser and the outside of the Heat Riser, this is only possible because of the insulation
and special positioning of the heat riser and the tremendous amount of heat that radiates off of the 55 gal drum / Heat Exchanger !
Because your building is so small, eventually your interior space will warm up to the point that the rooms temperature would equalize with the temperature of the skin of the Drum,
and No more heat could be radiated off of its skin ! At this point your R.M.H. will backdraft, filling your outside building with smoke !
It is interesting to note that as air is such a poor carrier of heat thru conduction or convection, that it would be the warming of the room through the re-radiation of heat energy off
of the interior walls that would mostly cause the Temperatures to Equalize !
However that being said, I have to admit that I don't know exactly what would happen if the R.M.H. had its own air supply and the room was a perfect vacuum ! as heat would still
radiate both ways I expect an equilibrium would be reached !
Even if you had an all metal outside building that would quickly radiate much of the Heat Energy through its exterior walls, I Think that sand, even wet sand would have problems
taking up the heat before your R.M.H. and its room reach Equalization !
It has been estimated that world wide there have been approximately 100,000 R.M.H.s built, almost all of them in the 6'', 7'', 8'', range, due to Friction loses and problems connected
to laminar Flow, for every working unit smaller than that, there are probably thousands of failed/abandoned builds, I would personally build a second R.M.H. before I would go big !
This is where I recommend going to
rocketstoves.com to pick up your PDF Copy $15.
oo of Evans' and Jackson's great book
Rocket Mass Heaters, there is
STILL No other book
in any language with as much
Rocket Mass Heater Information ! (and I don't make a nickel! )
Keep coming back to talk with your fellow members, with over 18,000 members you will always find someone that wants to talk about what you want to talk about ! Good Luck !
For the Good of the Craft, as always comments and questions are Solicited and Welcome! Think like fire, flow like gas, Don't be the Marshmallow ! PYRO - Magically Big AL !
)
