Glenn Herbert wrote:I see no particular reason why you couldn't have the bell/barrel on the outside, as long as there is sufficient buffering of some sort to keep people from bumping into the hot surface. The feed near the wall is another matter; you will have significant heat there, both radiant from the top of the feed and conduction through the feed walls and surrounding mass. That would require serious insulation, plus a real air gap to any combustible walls, even with a metal heat shield and airspace on the wall.
If you pulled the feed out just enough to make the cleanout near it extend horizontally between the feed and the wall, that would make a separation that I would feel comfortable with.
I also notice the "outside door" which swings back close to the feed. You would have to make sure that door was noncombustible or shielded adequately.
Glenn Herbert wrote:The shape and size of your proposed bench leads me to recommend swapping the serpentine duct for a pair of half-barrel bells. Essentially, you cut a 55 gallon barrel in half lengthwise and put the cut edges down, with the duct from the manifold flowing into the bottom of the first barrel, out the bottom of the first into the bottom of the second, and out the bottom of the second to the chimney. This allows hot gases to rise to the top of each barrel and give up their heat, while the cooler gases drop and exit at the bottom. It would simplify construction and maintenance (fewer cleanouts to handle), and is reputed to be more efficient than just ducting. It would definitely reduce friction in the airflow.
Satamax Antone wrote:http://s65.photobucket.com/user/mremine/library/NYC%20Rocket%20Stove%20Build/#/user/mremine/library/NYC%20Rocket%20Stove%20Build/?page=1&_suid=1472511087968034593128232003633
But how did the elephant get like that? What did you do? I think all we can do now is read this tiny ad:
Rocket Mass Heater Plans: Annex 6https://permies.com/wiki/138231/Rocket-Mass-Heater-Plans-Annex