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Continuously heating a pool can be expensive and the best ways to lower the cost are to have a cumbersome pool cover in addition to the equipment needed (solar or an AC-like heat pump). There must be a way to say, raise the temp of my pool 5-10 degrees using propane and a well crafted "heat exchanger". We don't go in the pool every day so if it cools off and we need to reheat we'll know the cost to do that is a tank of propane or so.

Does a propane heat exchanger exist? Can I make one myself? Can I use the same pump or should I set up a separate one just for heating?

Aarthi
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tooshel
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7 Answers7

9

When I was a kid, my much older brother heated the pool in his backyard by running a bunch of black painted pvc pipe to and fro on the fence, and then plumbed it into the filter system.

jeff
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Very late in answering here, but solar pool heating systems are great and pay themselves off in 1-1.5 years vs. propane and electric heaters. They are -- by a large margin -- the most cost-efficient renewable energy application that I know of.

I see that you said solar pool heating requires a pool cover. It does not. A pool cover helps greatly, especially in a cold or dry climate: almost all of the heat a pool loses is from evaporation. However, it isn't really needed for solar. Is an uncovered solar-heated pool going to be 95 degrees Fahrenheit pool in the Winter? No, but it is going to give you 8-20 (depending on the size of the array) degrees Fahrenheit for free, which would costs thousands each year if done with propane.

Also, solar pool heating and propane are not mutually exclusive. You can easily get a system that uses both, heating the pool at all times with solar (provided that the panels are hot enough -- properly installed solar pool-heating systems bypass the solar if the panels are cold,) but if that isn't adequate, you can turn the propane on. As stated earlier, this setup saves thousands a year vs. propane. The solar portion of the system will pay itself off in ~1 year vs. propane, and it will save you $10,000-$60,000 over the life of the panels.

T.J.L.
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Michael
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4

Is there something wrong a standard Propane Pool Heater?

http://search.intheswim.com/?q=propane%20pool%20heater

Some of the gas heaters linked above also have sizing guides and model info that can help you pick a heater large enough for your pool. Keep in mind that even with gas heat it usually takes 24h to warm the pool, so you don't turn on the heat and hop in.

For a pool that isn't used every day (or almost every day), an active heating system can be a waste of money.

If you don't use the pool all the time, I would consider something that is more "passive". Solar Heaters are pretty cheap, and the energy cost is basically zero. However, they don't provide a lot of heat (less so on a cloudy day), but it may be enough to enjoy the pool without shivering.

I'm not a fan of solar covers, unless you have a crank that allows you to easily cover/uncover the pool. The solar cover on our 27ft pool was so difficult to drag on and off (and keep it clean) that we gave up on it. We also ended up dragging a lot of crap into the pool.

Other options:

  • I had mixed results with a Solar Pill, but I also tried it late in the summer when the rains started.

  • Solar Rings look pretty cool. Might be easier to manage than the solar cover, and double as a pool toy. Expensive though.

myron-semack
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3

You could cool your attic and heat your pool with one device:

http://www.solarattic.com/PCS2docs/graphic.html

Costs about $5k installed.

richardtallent
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1

Answering a really old question... In the current season of Ask This Old House (aired during the 2012 Cambridge House TOH season), they used a heat exchanger to take waste heat from a heat pump (that the homeowner is already using to heat/cool his home) and use that to heat the pool. Something like on this site:

http://www.hotspotenergy.com/titanium-pool-heat-exchangers/

The output of the pool pump is plumbed to go through the heat exchanger.
The lineset serving the heat pump is spliced into the heat exchanger. There is a switch/controller that is part of the heat exchanger. When the heat pump runs, the controller detects if the pool needs to be heated (based on set temperature). If so, the refrigerant is routed through the heat exchanger, heating the water and getting dispersing the heat from inside the building. If the pool does not need to be heated, the refrigerant goes through heat pump as usual.

The heat exchanger was represented as using wasted heat (from inside the house) to heat the water, so the pool was heated for "free" without affecting the cooling of the house. Don't know if that is completely true or not, but that is what was said.

There is probably more to it, but that is what I remember from the Ask TOH show.

Note that in this segment of the show the homeowner already has a conventional heat pump that is used to heat/cool his home. The plumber/HVAC guy installed a heat exchanger that allows the transfer of the waste heat the heat pump generates during the cooling season into the pool water. This answer is not about having a dedicated heater for the pool. It is also not about heating the pool during the non-cooling season as the heat pump only generates waste heat when it is in cooling mode.

wageoghe
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If you definitely want to be able to use propane, or some artificial source, your best heat exchanger will be water, because it has such a high specific heat capacity, and in metal pipes, because metal conducts heat well. So essentially, you want a propane powered water boiler, with a set of pipes to circulate it through the pool. Of course the devil is in the details - how big should the boiler be, what burner and how hot, etc, etc.

For simplest setup, you could get a gas powered on-demand continuous water heater, then just run the pipes through the pool and back again. That takes care of all the details of boiler size, heat exchanger design, etc, but those continuous on-demand water heating systems are usually expensive. Hope this helps.

AWMoore
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I've always had an idea on how to more efficiently heat a pool:

For an in-ground pool made of concrete; attach radiant floor heating piping to the re-bar structure; connect this to a continous water heater and some sort of reservoir incase the water level gets to low and heat the pool from the inside out.

if laid out correctly, you could heat the pool from all sides - heat rises, transferring into the water.

I'm not a thermal engineer but I think it would work.

Could also use the water in the pool as the water that passes into the radiant floor piping and then dump the water back into the pool; not only would you heat the actual concrete and transfer into the water, but also heat the water going into the pool.

-Mario

lsiunsuex
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