Need advices - 1st build rocket mass

Hi,

I am located in Laval, Quebec  45.29N, 73.30W
zone 5a

Well, it's almost complete.

Here are some facts:
- 8 inch system
- 13 foot pipe (8 inches)
- 12 foot isolated chimney (7inch diameter)

I built this small greenhouse "earthsip style" 2 years ago and this year after collecting all the materials i went ahead and started building this rocket mass.

I am at the point where i'm about to glue everything together. Here are some pics i'll then explain where are my problems.

i doug a whole about 30inch deep to lower the RMH since the greenhouse is so small (visualize a triangle 17ft x 14ft x 10ft). This allowed me to put 1.5 inch isolation all around my pipes with 2 inch of dirts and rock at the bottom and about 6 inch all around.

- 1st problem:
The cleaning outlets have their opening pointing upward. The one near the chimney is protuding from the ground so very accessible.
and the one near the manifold, i will have to add about a foot of lenght because my goal is to cover as much of the RMH in the ground. I though about screwing a piece of metal to continue the roundness of the pipe and not creating a pocket. I will add a door for when it will be time to clean, i'll uncap the outlet and the open that litte door. The problem is that i don,t know if it,l lwork

- Second problem
You will see on the pictures that my barrel has not much clearance on the 3 sides:
- one side about 7inch
- second side 16inch
- Third side 11 inch
i plan on putting a metal barrier (29 gauge steel) fixed by non-combustible fixations, all around the barrel to protect the 3 sides. I will also do the same to protect the ceiling (all with as much air gap i can from the wall)
Will that work??? Before i started i though without truly measuring that the RMH would be much deeper and clearance would not be a problem.

I can says that for a first project, i made it tough on myself. First everything is reclaimed materials, i don't think i spent more that a 100$. Without experience i went ahead figuring solutions for obstacles as i moved forward.

I am almost there, and maybe not if it turns out that the heat barrier is not sufficient.

If someone is kind enougn to give me some answers.

Thanks
Stephane

7 inches of clearance to wood seems risky. A heat shield which provides 1 inch of air gap between the shield and the wood is obviously needed I would say on all 3 sides, and there should be an air gap at the bottom of the shield to allow air flow. You can shift the barrel so it's off center of the internal heat riser, moving it away from the closest walls. That will reduce the exhaust flow inside the barrel on those sides which are then constricted, and less heat will radiate out from that side. You could also stack some bricks between the barrel and the heat shield on those 3 sides, to absorb that radiant heat and release it more slowly into the space. Combined with the heat shield I would think (in my non-professional, not a building inspector opinion) that the wood should then be safe from charring over time.

Hi Mark,

Thanks for your input.

indeed adding a brick wall all around would definitely help capturing some heat. When i thaught about it, i saw that as building the brick wall next to the wood wall and having the metal shield between the barrel and the brick wall?

You are suggesting the opposite, so it should be a brick wall all around the barrel covering the 3 walls and then the metal shield fixed on the wood walls (with special fixations).

That led me to think.

What would happen if i built a cove (not sure it's the right word) around the barrel and on top, leaving a good foot of space on top of the barrel. My understanding is that it would not alter any heat dispersion from the barrel, actually it would all be concentrated in front, where i would like to have it, and the bricks would also act as a form of heat sink, absorbing heat and releasing it more slowly.

I guess all that hypothetical solution will have to be built to know for sure.


I attached a drawing to illustrate my idea

Thanks
Stephane

I think your alcove idea will work well. Bricks near the barrel will absorb and store heat, and greatly reduce the heat getting to the metal heat shield on the walls so that does not have a hard job protecting the wood.

I agree, the brick surround adds more mass that can absorb heat and then release it slowly. Is that insulation sheet going around the foundation perimeter? If you can isolate the soil you'll be heating from the soil outside which will be getting cold and wet, it will slow the heat loss a lot. Perhaps a layer of insulation on the outside of the cinder blocks is possible? I would aim to get it down at least 2 feet, deeper if possible. Be sure to tape up the edges or add some waterproof material to keep water out if possible. That will help keep the soil inside dryer and warmer for longer.