Geothermal heater

[addicted]

I am new to the pond thing but I was thinking about a geothermal pond heater. If took a posthole digger and drilled a 12" hole 4 feet deep, lined it with 10" pvc, filled it to 75% with 50/50antifreeze water mix, made a coiled heat exchanger and pumped water through it I should get about 45 to 50 degree water out depending on water flow and heat transfer to my heat exchanger. of cource the top would be insulated and capped.

Anybody tried this? Thoughts?

 

[DrDave]

Welcome to the forum.
I like the way you think. I'm not sure how the PVC will work with the ethylene glycol. You might want to do some long term soak tests and see if it reacts with the Poly Vinyl Chloride.

I think I would go deeper to avoid the frost line.

 

[Pondmaster]

I am new to the pond thing but I was thinking about a geothermal pond heater. If took a posthole digger and drilled a 12" hole 4 feet deep, lined it with 10" pvc, filled it to 75% with 50/50antifreeze water mix, made a coiled heat exchanger and pumped water through it I should get about 45 to 50 degree water out depending on water flow and heat transfer to my heat exchanger. of cource the top would be insulated and capped.

Anybody tried this? Thoughts?

I had thought about this also, trenching a much longer line would give you longer contact time which you would need for the GThermal to be effective. The following link might prove to be a better option. How deep is your frost line? In middle Tennessee it is 11-18" inches but I'm originally from Iowa where the frost line was 6 feet.

http://www.koifishponds.com/pond_heaters.htm

 

[stroppy]

any photes addicted ...admit to not even know what your talking about, but would love to learn !! :0)

 

[koiguy1969]

i toyed with a similiar idea to but for the opposite effect....a lengthy coil of 1' irrigation tubing buried deep with a small pump to cool water in the hot summer.

 

[addicted]

Wow, I am surprised at the intrest in this. Frost line is 32" in central Ohio. Code for water lines is 36". That is a 50 year worst case. Deeper would be better but that's how deep my post hole digger goes. Good point on the cooling factor, that would be a bonus. Steel or aluminum casing would hold up to the glycol better and give better heat transfer but I think cost would rise dramatically. I will have to see if I could salvage a piece of pipe and weld a cap on it. If I try it and it's a miserable failure all I have is a hole to fill. No harm done. I will keep noodling on a better casing idea. Sorry, Only pictures are the ones in my head.