Underground Solar Heating

[RiCoda]

Hi
Thought i'd let you know about my new pool installation.

I just installed a 8metre x 4metre fibreglass inground pool with about 50square metres of concrete around it. Into this concrete i've installed over 200 metres of poly pipe in 4 seperate loops all tied to the concrete reo mesh.

The plan is the sun heats the concrete, water pumped thru the tubes, gets heated and circulates to the pool.

Initial testing with a water hose hooked to one line at about 18deg C inlet temp saw a constant 28deg C outlet about 5pm in the afternoon on a 30deg C day. flow rate was about 40 l/min (only holding hose on pipe), but final setup can take 4 times that flow with the 4 seperate loops of tube, each seperate loop will feed water in the oposite direction to the adjacent one to maximise heat gain. It "should have the added benifit of cooling the concrete underfoot as well.

The concrete is standard grey at the moment, but is too be pattern sprayed to a sandstone/bluestone shade, so this should increase heat output slightly.

Sounds promising so far for zero cost outlay, tubing was given to me and i already had a small pump to use, so should have it connected in the next week or so and see if it actually does work, there is provision on the pump setup to run a few loops of poly on the roof of the shed as well, but for this season i'll just try my "underground" solar heating.

cheers from downunder Dee.

[Pool Owner]

RiCoda, this sounds interesting. Let me know how it goes as the seasons change.