before anyone asks, yes i have read the book:) ( i have also done a cob building workshop, that is where i learned about rmh)
the house we are going to be heating is around 2000 square feet. we live in a colorado ski town, and our only form of heat is the very poorly placed fireplace/stove placed in the corner. it is a rental, but we have the permission of our landlord to build it as long as we abide by some rules he laid out. 1. it needs to be removable, as he is not completely sold on it working, and new tenants down the road might not want it. he has read some of the info and watched some videos, but he wants to see it in action, so it has to be semi removable. cob is, so i am alright with it, but see rule 2. 2. it has to be light enough that it does not hurt the foundation/ craw space we live on top of. 3. lastly it has to use the existing chimney. this leads me to the questions.
the pictures below are where i was going to build it. the barrel will go where the dog crate is and the chairs are stacked up, the bench will be where the couch is, then i was going to run the pipe just above the floor over to the fireplace. i was going to run stove pipe over the stone and cover it in cob and plaster to make it into thermal mass as well as the bench, then exhaust it up the existing chimney. i was also thinking about building a seat by the door and running some pipe through it to make a nice seat and increase the thermal battery. i am a bit worried about it being too much "movement" in the piping. i measured it all out, and with out the seat by the door it will be around 25' of exhaust, with the seat it will be around 32'. i should also note that i plan on using 8" ducting for the bench, and then moving into 6" for the floor crossing and fireplace/seat area.
questions i have:
1. is there a lighter thermal mass that i could use instead of cob or broken up concrete that will still function well for the bench/seat?
2. the ceiling clearance from the top of the barrel is going to be about 4', is that enough? if we use a hot water tank that is taller, can we incase most of it in cob to keep it cooler?
3. looking at the pictures, do you see a better placement for the rmh?
4. i am having a hard time tracking down a barrel up here in the mountains, there isn't a scrap yard for a few hours, and i haven't had any luck on finding one on criags list. can i use a metal trash can from home depot? any ideas?
5. where it crosses the floor part, it is 6 1/2 high, and i will be running 6" ducting, i was going to pack the wood floor with vermiculite and then just cob over it, then place a flagstone where it will be stepped on. any thoughts on this? its the best solution i could come up with to get the exhaust over to the fireplace. i was thinking about going down to 4", but it would create a bottleneck, but i could use 2 placed side by side...
6. thoughts on the extra seat by the door. it will add 4 45 degree turns to the overall design.
thanks for any input:)