Rocket Mass Water Heater

[Jonathan Hall]

So I am putting together a Rocket Stove for my greenhouse and have dreamed up an idea and can't really seem to find any good answers out there. So hopefully someone has either done this or has some ideas why it would or would not work.

Here is the primary concept without the added modification just so you know what I am working with;

Rocket Stove, built inground (no above ground thermal mass save for the heat riser and barrel). The exhaust runs underground just below the surface and winds underneath my four IBC fish tanks. This essentially radiates up to heat the tanks as well as heating the ground as my "mass".

Now for the modification idea;

Place a stainless steel barrel (smaller) on top of the rocket stoves barrel. Place a stainless steel drain hose which will drain back into the fish tank.

Take a very small water pump and pump the water out and into the top of the stainless water heating barrel, and then the water should essentially get heated and drain back into the fish tanks.

I selected stainless because it appears to be the only material that doesn't seem to harm an Aquaponics system/fish.

I considered pex tubing as it would be more movable so I could take it down easier, but it has a max temperature of 200 degrees F. I would be afraid I might melt it, so I would have to put some sort of insulation between it and the top of the rocket stove otherwise it might get too hot. This could be another alternative if steel piping is to tricky.

The example piping I was looking at can be seen here; Stainless Steel Washing Machine Hose

Alternate Option;

Make the water heater, heat exchanger a closed loop. and just have the hoses lay in the water with no waterflow to the water, just let the water cycle naturally and radiate the heat.

What do you all think?

[Jon Nose]

consider running the thermal mass so that the fish tanks are sitting in between the rows, make sure you insulate where you do not want the heat to go, you can run your pipes in the thermal mass as opposed to all rock

[Jonathan Hall]

There will not be any thermal mass (cob) above ground to put the tanks between/around. The stove exhaust pipe will be coiled underground directly beneath the fish tanks, radiating up so they,the tanks, are essentially the thermal mass. 

However, I may be able to make pex work if I just loop it near the exhaust where there is not extreme heat. Perhaps I could even bury the barrel near the exit of the heat riser and pump out from that. Utilizing an out of water water pump so it is not subject to direct heat.

Jon Nose said:

consider running the thermal mass so that the fish tanks are sitting in between the rows, make sure you insulate where you do not want the heat to go, you can run your pipes in the thermal mass as opposed to all rock

[Jon Nose]

Jonathan Hall said:

There will not be any thermal mass (cob) above ground to put the tanks between/around. The stove exhaust pipe will be coiled underground directly beneath the fish tanks, radiating up so they,the tanks, are essentially the thermal mass. 

However, I may be able to make pex work if I just loop it near the exhaust where there is not extreme heat. Perhaps I could even bury the barrel near the exit of the heat riser and pump out from that. Utilizing an out of water water pump so it is not subject to direct heat.

Jon Nose said:

consider running the thermal mass so that the fish tanks are sitting in between the rows, make sure you insulate where you do not want the heat to go, you can run your pipes in the thermal mass as opposed to all rock

[Jon Nose]

Not sure what happened to my last reply .. check my pics as have already built a similar setup...

[Jonathan Hall]

Will check it out, thanks!