Underground tank

[gimmeWood]

I am new to this site and am in the research phase for a gasification/storage project. I am currently leaning towards getting a tarm or EKO and building a storage tank of ~1000 gallons. For the storage I am thinking about busting through the slab in my basement. I would dig a roughly 6 by 6 by 6 foot hole and pour in a floor and walls with 4 inches of concrete. My initial idea was to use pink extruded polystyrene boards for the bulk of the insulation, but from looking at the specs, it only appears to be rated to 160 F. Has anybody ever used EPS for insulation? Any problems? The other thought would be to put in some sheets of EPS following by a layer of 2x4 stud framing with fiberglass bats to provide a buffer between the 180 F water and the 160 F EPS. Then I would do a layer of aluminum foil followed by epdm.

Has anybody here ever built an under the slab tank like this? Does it sound do-able?

 

[EForest]

I had planned a similar tank but was talked/posted out of it here. If you can find a used propane tank it would be a pressurized system with little head ache.
Many are available if you ask around. I was recently told of a guy with many up for grabs. If you're interested I'll follow up and foward the info to you.

 

[gimmeWood]

Thanks for the reply. I do like the idea of pressurized, mainly because it removes the need for heat exchanger. As I see it, here are the pros and cons for each:

Pressurized pros / Open cons:
- Pressurized is clean & tidy
- Heat exchangers required for open system are expensive, pressurized does not need them
- Open systems have the potential for evaporation issues

Pressurized cons / Open pros:
- Pressurized requires expensive expansion tank
- If I put an open tank in the ground a liner failure will not result in flooding. Pressurized tank failure would spill water in the basement
- With open system I can easily add an extra heat exchanger in the future so that I can add a driveway snow melt zone.

What did I miss?

 

[reaperman]

If your looking for 1000 gallons capacity. Your proposed hole of 6x6x6 is about 1615 gallons of water. If your not familiar with cubic feet to gallons conversion the formula is LxWxHx7.5 Sounds like an ambitious project to handle roughly 8 yards of dirt. If your in sandy soil, cave-ins will haunt you making your hole much larger than expected. Clay soil will keep you up to date on all of latest naughty words. Best of luck

 

[gimmeWood]

If your looking for 1000 gallons capacity. Your proposed hole of 6x6x6 is about 1615 gallons of water. If your not familiar with cubic feet to gallons conversion the formula is LxWxHx7.5 Sounds like an ambitious project to handle roughly 8 yards of dirt. If your in sandy soil, cave-ins will haunt you making your hole much larger than expected. Clay soil will keep you up to date on all of latest naughty words. Best of luck

ahh, very observant. My original calculation gave me 5 by 5 by 5 to get ~1000 gallons, but then I upped it to 6 by 6 by 6 to account for the concrete walls and insulation. The exact dimensions will be determined once i decide on the insulation.