My father-in-law is interested in a propane pool heater and I talked to my boss about it to see if we could get one at a cheaper price and he told me to make a heat pump pool heater out of an old AC system. Does anyone know any good designs for this for running the water through the coil?
Heat Pump pool heater
jperigo
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My father-in-law is interested in a propane pool heater and I talked to my boss about it to see if we could get one at a cheaper price and he told me to make a heat pump pool heater out of an old AC system. Does anyone know any good designs for this for running the water through the coil?
Sounds like a fun project. Get a coaxial or plate heat exchanger. Use your regular air conditioner condenser and heat the pool anytime you are calling for cooling in the house. You will most likely need a three way valve so yo can select if your condenser is the air coil or coaxial/plate heat exchanger so you dont overheat your pool.
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Yes; I do.
BTW: I like your boss already. <g>
Bear in mind that a propane fired pool heater will be about 300-500K BTU's. And even a five ton heat pump pool heater will only be about 75K BTU's.
How big is the pool?
PHM
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BTW: I like your boss already. <g>
Bear in mind that a propane fired pool heater will be about 300-500K BTU's. And even a five ton heat pump pool heater will only be about 75K BTU's.
How big is the pool?
PHM
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You can just pipe them in series - you will never overheat the pool. <g>
PHM
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PHM
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OK; let's talk about some general numbers.
Assuming an in ground pool - the water temperature will stabilize at somewhere between ground temperature in that area and any solar heat gain - Less all the night time heat losses.
Whew! Let's just call it 70º water in the unheated pool. <g>
6000 gallons of water weighs about 50,000 lbs. The specific heat of water is 1.0 So each degree of temperature increase will require adding 50,000 BTU's of heat to the water. So if you want the water to be 80º (ten degrees warmer) you will have to add 500,000 BTU's. If you are adding 50,000 BTU's per hour - it will take ten hours of continuous heat pump operation to accomplish.
But . . . . you also have to add all the BTU's which are being lost during the time you are heating the water. The BTU's you add don't just accumulate - they immediately start to escape. This is why you cannot add BTU's too slowly - the BTU's will escape faster than you can add them. And this is why fueled pool heaters are 300-700K BTU's - so the pool can be heated quickly enough to overcome all the heat losses.
Using the building's AC to heat the pool water is even worse - because any time you need to be heating the pool - the AC is not going to be running 100% of the time. <g>
PHM
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Assuming an in ground pool - the water temperature will stabilize at somewhere between ground temperature in that area and any solar heat gain - Less all the night time heat losses.
Whew! Let's just call it 70º water in the unheated pool. <g>
6000 gallons of water weighs about 50,000 lbs. The specific heat of water is 1.0 So each degree of temperature increase will require adding 50,000 BTU's of heat to the water. So if you want the water to be 80º (ten degrees warmer) you will have to add 500,000 BTU's. If you are adding 50,000 BTU's per hour - it will take ten hours of continuous heat pump operation to accomplish.
But . . . . you also have to add all the BTU's which are being lost during the time you are heating the water. The BTU's you add don't just accumulate - they immediately start to escape. This is why you cannot add BTU's too slowly - the BTU's will escape faster than you can add them. And this is why fueled pool heaters are 300-700K BTU's - so the pool can be heated quickly enough to overcome all the heat losses.
Using the building's AC to heat the pool water is even worse - because any time you need to be heating the pool - the AC is not going to be running 100% of the time. <g>
PHM
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I'd imagine it is very dependent on where the pool is. 99* in Florida vs 99* in Nevada. Towards the end of summer you may need a pool chiller in Florida and not in Nevada. Do to the Psychometrics. Or am I off track. Solar covers work magic also
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The pool is an above ground pool and it is in the Pacific Northwest. are average temp during the summer time is usually in the mid-70s during the day and low 60s high 50s at night. We tried a solar heater last year by putting a bunch of spiral black plastic pipe onto a black painted board and letting the water flow through that in the sun and it would heat the pool a couple of degrees during the course of an entire day but not enough to make a difference. As for the AC system idea it would be just for the pool and not for the building AC as there is no ductwork in this home so there is no AC system for this home. My boss's idea was to use a heat pump to draw the heat out of the outside air and I believe the condenser coil with the high discharge temperature to heat the water that flows around the coil. I think it was his idea that it would be cheaper than purchasing and running a propane heater because most all the parts would be free.
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I believe someone, maybe Rheem makes such an animal. Don't they have sort of a heat pump domestic water heater thing-of-a-bob? What PHM is sayin', I believe, is get a real heater and get the job done! if you're gonna do it. I'm no pool guy but 6,000 gal. doesn't sound like a very large pool. May not need a real big heater. Heat pumps only raise air temps 25 degrees or so, but dense water??? At 50-60 degrees to get heat at night and heat water? By the way what's the electric rates like?
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As far as using a solar heater the surface area of the solar collector would need to be at minimum 1/2 of the surface area of the pool. Another important tidbit is you will significantly reduce your heat loss if you cover the pool when you are not using it as most of the heat loss is due to evaporation.
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Reverse cycle chiller.
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That is exactly what he has been asking about all along. <g>
PHM
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PHM
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In a way but he wants to frankenstein it. There are better products on the market to handle this project. Products tested and proven. But I know you PHM, you live for this stuff. Lol.
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Well; i do like to have some fun with it all if I can. <g>
And the OP's original post at least seemed to imply that he wanted to do it with 'free' AC parts. It was his boss's suggestion that he build it himself.
I do like the idea and the project but I wanted to caution that a large residential-type system - say; five tons - will not heat the pool especially well. And certainly not quickly.
Yes; it will do Something - but it will be about 20% of typical pool heater capacity.
PHM
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And the OP's original post at least seemed to imply that he wanted to do it with 'free' AC parts. It was his boss's suggestion that he build it himself.
I do like the idea and the project but I wanted to caution that a large residential-type system - say; five tons - will not heat the pool especially well. And certainly not quickly.
Yes; it will do Something - but it will be about 20% of typical pool heater capacity.
PHM
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