I was at the hardware store this morning, and ran into four sections of 90* elbows fit together. They were still strapped together, so I assumed they were shipped that way. They were 9" diameter pipe, and fit together into a 24" diameter circle.
My thought (since I'm thinking a verticle mass) was a 24" diameter spiral set into a 36" x 36" square foot print (cob) about five or six feet high. Hot gasses coming down the barrel funneled into the spiral and then out the vent.
I guess this is to reduce the mass to the 3foot square ?? Only down side is that there wouldn't be much mass would there ?
I just found by accident that I was concentrating the ducted heat in one place which is what you're wanting right?
I'm just setting up the system (another thread) Temporary duct runs out of the barrel - through a small bench and for now out the wall (it will run through raised beds in the greenhouse. )
to temporarily join 2 pieces of 5" duct together I added a sleeve of 6" over the 2 ducts and taped them up - there's a 4-5 inch gap between the ends of the 5" duct.......... this would be easier if i drew it but hey
Just this small gap and expansion area increased and concentrated the heat dramatically. you can't touch the sleeve but the exit duct is "hot but you can touch it" (briefly !) - yeah I need a decent thermometer
I'm going to experiment a bit with the idea because i don't want too much heat in the growing beds - just a gentle warmth so concentrating the available heat in the cob seems like a plan
So rather than lose the mass to a complicated spiral duct work just vary the diameter of the duct along its length (height in your case) easier to clean out too... well ish
Hope this at least vaguely makes sense
posted 7 years ago
What I'm trying to do is set the mass up on end ..... my mass would be 3' x 3' where it sits on the floor, but it would be five or six feet tall. I have a space that measures about 6' x 4' (total) to put a stove on...... I cannot run the mass part of the Rocket Mass Heater lenght wise....no room, but I have a floor to ceiling height of just over eight feet. I'm wanting to modify the RMH to fit my space.
Don in the Mountains of West Virginia (We had ten inches of snow last weekend!)
Location: Southern alps, on the French side of the french /italian border 5000ft elevation
posted 7 years ago
Teacher, i think you should do a rocketrocketrocket
I mean, do something along the lines of mine, with tall gaz botle, or len's with the water heater tank. Then you exit the flue into another thingy like the heat riser, a central tube, and a radiator outside, if you could find gaz botles like mine, you could may be make four of theses in series. And dry stack bricks around. May be once a year you would have to dismantle all to clean thought.
Re thinking about your elbows, i think they would be somewhat easier to clean.
What type were they? Smoth inside? Or crimped metal? Crimped metal might not be too good. If i realy had to do something along the lines of a spiral, i would take double walled smooth flexable tube special for tubing chimneys.
I think, you could do the same kind of stuff, only taller. Let say, your heat riser goes to 15inch from the ceiling, and build the bricks around wide, so the downflow is slow, and there's some convection around the heat riser. Just an idea.