Beau Davidson wrote:-If I build a single brick bell directly over the heat riser, and adhere to 57 square feet for my 6 inch tube as per the above material, is there a standard rule on how far the unit needs to be from the nearest wall?
-Can I vent cool exhaust using regular ducting, or do I need some heavier duty stuff?
-Do I need to seal the interior of the bell with cob or other to prevent gas leaks on startup?
Glenn Herbert wrote:"So it need to be (if I remember correctly) 2" from the nearest combustible wall."
Peter, I think you meant 2 feet, not 2 inches, correct?
Beau Davidson wrote:The burn tunnel included some leftover masonry cement and a hearty inclusion of vermiculite.
The heat riser is cob with sawdust, vermiculite, and perlite, mixed to a very lite and crumbly and packed down one run at a time.
I think I’ll feed this into a simple stratification bench packed in sand, then out the chimney in the rear. Considering a small oven on top as well.
As inspired by many of your comments, I’m building an addition in the front to house this. If it’s clean a reliable, I may knock out the wall between to bring it in to the rest of the cottage.
Gerry Parent wrote:
Do you know what temperature your masonry cement rated for? High heat rating is definitely needed in this area.
Gerry Parent wrote:By your picture, it looks like there is an inner of cob and sawdust layer and then surrounded by vermiculite and perlite. Cob is pretty dense as a material for a heat riser, unless you mean clay slip as the binding agent?
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