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mnschu 04-27-2012 06:01 PM

Geothermal heat pump using pool as heat sink
I have a question about installation of a geothermal open loop system using a swimming pool as the heat sink. My web searches show sporadic results, not much info I can find.
I would like to install such a system if it is feasible.
Some info about my house:
Location: N. CA (San Jose, CA)
Pool: In ground, 26,000 - 30,000 gal (20x40 feet), salt water
House: Currently 1,800 square feet, single story, plan to expand to 2,300
Current HVAC: Just forced air NG furnace, no A/C

I was planning to replace all the duct works and install traditional A/C, but want to investigate possibility of geothermal.

Due to the termperate weather, the pool seems like a good candidate for a heat sink. Also, it would aid in heating the pool.

From what I have researched so far, I would want to install an open loop system, taking the water from my pool, then dumping it back in. Pool would get cooling effect from evaporation. Heating should not be a problem, as winters are quite mild, and I always have the gas furnace as backup.

Has anyone done this? If so, how was the plumbing done? Tie into the pool plumbing with check valves so pool pump and geothermal pump do to affect each other? Or use pool pump for everything? Any advice or suggestion from someone that has experience with geothermal?

Any recommendation for geothermal heat pump? I understand I need one with cupro-nickel heat exchanger due to salt water. Which is the best?


gregzoll 04-27-2012 06:26 PM

Maybe in Kentucky, if you were using it for your still. This just has wrong written over it in so many ways

carmon 04-27-2012 06:27 PM

I will be of zero help on this topic..... I thought pools were for swimming in...

beenthere 04-27-2012 10:06 PM

Don't believe your pool will cool from evaporation as much as you think. Does your pool water ever feel almost warm in the summer?

mnschu 05-09-2012 02:54 PM

heat recovery from AC to heat pool
My original question related to geothermal, however I found this product that uses traditional A/C.

This has a refrigerant to water heat exchanger, which seems the most efficient for an AC. In my search, I did come across some air to water heat exchangers that retrofit to A/C as well, but this seems better.

My question for this product is if it will be reliable.
This brochure shows more details:

Basically, there is a controller that will switch the refrigerant from going to your normal A/C condenser to the heat exchanger using your pool water. This will heat your pool. If your pool gets too hot, it will switch back to using your condenser.

Any issues with this setup?


beenthere 05-09-2012 04:14 PM

How long will it take to get a ROI on it.

mnschu 05-09-2012 04:55 PM

I don't think I can quantify ROI, since the reason is to give longer swim season and warmer, more enjoyably pool. The unit cost $1,800 plus installation.
Similar to the A/C, we can't quantify ROI, as we don't have one currently, so the purchase of A/C is to get a more comfortable home.

Can someone comment on how much it would cost to install such a unit in San Fran Bay Area? According to company it takes about 4-5 hours for an A/C repair tech to install. The pool plumbing part and electrical I can do myself.

beenthere 05-09-2012 05:14 PM

You'll need to get prices from companies in your area. The rates a company charges in one area, may not be remotely close to what they charge in your area.

jogr 05-12-2012 11:09 PM

If your pool is salt water then that complicates things. Most water source heat pumps aren't designed for salt water.

Earthwell 05-17-2012 08:10 PM

A few problems with the pool setup
Unfortunately, there are a few problems with the pool as a heat sink Idea for an open source geothermal system.

1. Amount of water. The amount of water required for a open source geothermal varies depending on the cooling load. But it can be quite significant. The pool would work for a while, but then it just wouldn't cool off fast enough. Also, when you need the cooling in your house the most is when you would have the toughest time getting the water in your pool to cool off. The reason geothermal works is because the water is down in the earth, where it's not baking in the sun.

2. Salt water in the pool will degrade the heat exchanger in the geothermal system quite quickly resulting in some major problems.

Innovative thinking though, I like it!

Jonathan Broscious
Earthwell Energies

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