Heating my pool with my house, or cooling my house with my pool?

xmorganx

There has to be a way to do this- I just don't know enough about AC, heat pumps or pools. I live downtown, my house is small (750 sq feet per floor, 2 floors, soon to be 3). Like most city dwellers, I don't actually have a pool or AC, but 2 record hot summers, combined with municipal pools being closed due to Covid are making me reconsider both. The question is this: there must be some relatively simple way to set up an exchange using the pool water to absorb the excess heat from the house, thereby heating the pool and cooling the house. All the commercially available systems I see use 2 separate heat pumps (1 to heat the pool and one to cool the house), but this seems wasteful and sort of pointless, the pool being such a lovely heatsink all by itself...
I don't quite understand how to dump one into the other using the same machine.
Any creative ideas?

Jamie Hall

Depends on what heating system your house has. If it's forced air, what you need is a water to air heat pump/AC system -- there are a number of them. Usually sold for "geothermal" heating (a misnomer, but commonly used). The idea for heating is that the pool water is the heat source, pumped through the heat pump's evaporator, and the house has a heating coil in the ducting which condenses the refrigerant and shoots it back to the heat pump. In the summer when you want cooling, the system reverses.

Quite common, really -- at least in some parts of the country.

You will heat the pool in the summer that way. And you may cool it -- perhaps too much -- in the winter, depending on where you live.

Now... if your home heating system is hot water, problem. Radiant floors work well enough with water to water heat pumps or air to water heat pumps for heating, but not for cooling. And conventional radiators or baseboards are truly problematic -- there are a very small number of heat pumps which can reach those temperatures, but... pricey.

EBEBRATT-Ed

I could see a Geo heat pump working well for a pool as pool water is about 80-82 degrees. Not sure the HP would run long enough to heat the pool on it's own.

The other issue is the hotter the outside temp the warmer the pool will be naturally so when the ac is running hard the pool needs the least heat

Joe_Dunham

So you mean a central air system with a water cooled condenser? (pool water to cool the condenser)

ChrisJ

From what I recall,
You'll rapidly overheat the pool and it'll be useless for both swimming and cooling the condenser.


There's certainly no easy, off the shelf way regardless.

hot_rod

What part of the country? I suspect the pool would not be a large enough "sink" with not enough volume to cover either heating or cooling load.

If you performed a load calc for the 1500 square feet of home you could easily determine what is needed for testing and cooling and what the pool could offer.

Starting about this time of year, folks around me are looking for ways to cool the pools down, not add additional heat.

Big Ed_4

I have a customer that has that set up with two AC condensers connected to pool heat exchanger . The. installer installed an switch with selonodes to bypass heat exchanger and go to fan cooled .. House was two zone cooling with a large pool .

xmorganx

Hmmm, I guess it won't work out after all. Thanks you all for your insights. I live in Montreal- the season is short and a pool without a heater is only useful a few weeks a year. The same reason stands for why we didn't install AC to begin with. I'm not really looking to keep the house at 18 when it's 40 out, just a little something to take the edge off. We were planning on installing a little mini split on the 2nd floor when we renovate it and calling that good for the rest of the house. The heating is radiant floor, so no way to tap into that really. I don't want to put an exchanger on the boiler, and the boiler would be too small anyways. It just seems such a waste to dump all that heat outside when it could do something useful.....
For the moment the pool remains theoretical anyways...
Thanks again

EdTheHeaterMan

The actual needs for your heating and cooling are not timed properly. Starting the heating for the pool in April when you don't need any air-conditioning at all would make the house too cold, so now you need to operate the boiler more to compensate for the overcooling of your home.

I have found a refrigerant to water condenser that you place on a water heater. As the summer calls for more air-conditioning, the heat from the compressor goes to the water heater heat exchanger first, then to the outdoor condenser. That way if the water heater is satisfied and does no take all the heat from the AC compressor, the standard refrigerant to air condenser is available. A guy in Florida actually manufacturers the product. Several years retired now but I called the phone number 2 years ago and HE ANSWERED THE PHONE. If you are interested in going into business and manufacturing the thing, maybe you can talk to him. If interested, i'll look for the number

xmorganx

Fascinating! I don't think I'm at a point in my life where starting a new manufacturing business is in the cards, but if ever you see a link with a schematic of sorts I'd love to take a look. I see a real application on light commercial. For a while (some time back) I was doing a whole lot of work for a building to management company that housed a lot of servers. They were using water cooled compressors and I was there to add more and more and more drains (the wastefulness of this is unbelievable...) I couldn't take the responsibility for doing it there, but I have a friend who also has a lot of servers in his house and as an experiment I set up a sort of cooling exchanger/ preheat for his dhw. It was rudimentary, but it worked. And I agree that the timing is off- I understand that I would require a dedicated heater for the theoretical pool, it was more a question of reusing the excess heat from the house (semi-passively cooling the house if you will) instead of contributing to the îlots de chaleur ( heat Islands? I'm not sure how to translate this expression, the effect of urban environments with a lot of paved surfaces?)
Thanks again

xmorganx

*building management

hot_rod

xmorganx said:

Fascinating! I don't think I'm at a point in my life where starting a new manufacturing business is in the cards, but if ever you see a link with a schematic of sorts I'd love to take a look. I see a real application on light commercial. For a while (some time back) I was doing a whole lot of work for a building to management company that housed a lot of servers. They were using water cooled compressors and I was there to add more and more and more drains (the wastefulness of this is unbelievable...) I couldn't take the responsibility for doing it there, but I have a friend who also has a lot of servers in his house and as an experiment I set up a sort of cooling exchanger/ preheat for his dhw. It was rudimentary, but it worked. And I agree that the timing is off- I understand that I would require a dedicated heater for the theoretical pool, it was more a question of reusing the excess heat from the house (semi-passively cooling the house if you will) instead of contributing to the îlots de chaleur ( heat Islands? I'm not sure how to translate this expression, the effect of urban environments with a lot of paved surfaces?)

Thanks again

Plenty of unique way to move heat around.

I think Grundfos makes heat exchanger units for server farms to harvest that waste heat, or at least move it hydronically. I have seen some DIY computer cooling ideas on You Tube.

I have also seen restaurants with water tanks that refrigeration dumps heat into for energy recovery.

Same with driveway or parking lot heat recovery to DHW or pools heat, matching a dump load is always a challenge.

I think a driveway snowmelt to pool might work in an area like yours where the ambient is not overheating the pool. The driveway could be a basic unglazed solar collector

xmorganx

Thanks Bob ( hot rod). BTW you should know that you're a celebrity of sorts if you didn't already ( I, for one, have your book and read all your awkwardly translated articles in the French version of mechanical business. And the English ones too...) The driveway snowmelt would require a driveway, so not sure how well that would work in my application. Quoique, i see the logic- perhaps I could convince the city to allow me to cool the laneway pavement, in exchange for the laneway heat.
I've come up with lots of creative ideas for heat exchange through years of insomnia
It seems often the biggest challenge is budget, at least in my area, and whilst many fun ideas could make sense on commercial ( office buildings or apartment complexes, a number of industrial applications also) I hesitate to guarantee without giving it a try on somewhere safer. Home owners are more likely to let you try but less able to absorb the cost of an idea not working. So I try stuff out in my building, but there are limits to how much mechanical a triplex needs...

xmorganx

And I'll check the Grundfos units, if only to have a proposition the next time the MGT company calls. Their (Grundfos') modulating booster pumps are a lifesaver (sanity saver) in a different application for a similar type of building.

hot_rod

xmorganx said:

Thanks Bob ( hot rod). BTW you should know that you're a celebrity of sorts if you didn't already ( I, for one, have your book and read all your awkwardly translated articles in the French version of mechanical business. And the English ones too...) The driveway snowmelt would require a driveway, so not sure how well that would work in my application. Quoique, i see the logic- perhaps I could convince the city to allow me to cool the laneway pavement, in exchange for the laneway heat.

I've come up with lots of creative ideas for heat exchange through years of insomnia

It seems often the biggest challenge is budget, at least in my area, and whilst many fun ideas could make sense on commercial ( office buildings or apartment complexes, a number of industrial applications also) I hesitate to guarantee without giving it a try on somewhere safer. Home owners are more likely to let you try but less able to absorb the cost of an idea not working. So I try stuff out in my building, but there are limits to how much mechanical a triplex needs...

Thanks for reading my ramblings. I'm just an inquisitive plumber, been chasing free or cheap energy transfer my entire mechanical life

I'm always glad to share what I have learned, the wins and loses.

Here is a link to the Caleffi website, we do have a list of French language product videos if that helps.

https://www.youtube.com/user/CaleffiVideoProjects/playlists

jumper

ChrisJ said:

From what I recall,
You'll rapidly overheat the pool and it'll be useless for both swimming and cooling the condenser.

There's certainly no easy, off the shelf way regardless.

My experience in Mississauga,Canada was that outdoor pool got quite warm. A/C still managed. Circulated pool water directly through condenser located in basement while pool was above ground.

HDE_2

I did it no problem with a dual coil hot gas to water heat exchanger coil piped into hot gas discharge, between compressor and condenser coil and fitting it inside condenser. I installed a separate 3/4 HP pool pump activated with a dual aquastat, sidearm relay off of condenser contactor to complete heat loop exchange, drawing from pool return pipe and reinjecting downstream. I installed a head pressure control to operate the condenser fan. Added up similar to solar costs.

JUGHNE

Is the water side subject to freezing or can you drain/blow it out in the winter.....if you have winter?