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Thread: Solar Pool and Hot Water Heating

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    Solar Pool and Hot Water Heating

    Hello ALL:

    I just got back from a Trade Show, and there was one company that was attempting to sell Vacuated Tubes for both Solar Heating of a pool, and Solar Heating of Domestic Hot Water.

    Being the skeptic that I am, I am wondering if there is anyone out there who has such a system, or even has a system that just does their Domestic Hot Water. Are you happy with it, are you saving over 50% of your hot water usage? Can this system also be plumbed to use the excess hot water in the summer for your pool, rather then just plain dumping it?

    Look forward to seeing some replies, being an ower of a Hybrid I am always looking at ways to save and help the environment at the same time.

    Richard

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    JasonLion's Avatar
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    Re: Solar Pool and Hot Water Heating

    You should take a look at this topic on solar heating technology comparison.

    The quick summary is that evacuated tubes can be used to heat the pool but they tend to be about half as efficient as regular solar pool heating panels in typical usage.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Solar Pool and Hot Water Heating

    Hi Jason:

    Amazing how they dont tell you this, they gave me the impression that these tubes or flat black panels would provide twice the heat that the Fafco panels I have up now would.

    My pool is 14 X 28, with about 392 Sq Ft of Surface area, I have 240 Sq Ft of panels on roof. I am getting great heat during July/Aug, but in the spring and fall I cant get it much over 74. I live just above Maine, and am looking at trying to get this better.

    A friend has a heat pump and he spends 180 for each of those shoulder months to keep his pool over 80 degrees.

    What would you recommend?


    Richard

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    Re: Solar Pool and Hot Water Heating

    Given that the flat black mat panels such as those from Fafco are 80% efficient (i.e. absorb 80% of the sun's energy over the area of the panel on the roof) on a calm sunny day, I don't see how they could claim that any other technology could be twice as effective -- that's impossible. It is true that in conditions where the air temperature is cooler than the pool water temperature and there is wind, then the panel efficiency drops so there is a point when the glazed panel becomes more efficient than black mat, but the evacuated tube panel is not very efficient over it's area. It's main advantage is when the temperature difference between the air and the water is very large, such as with domestic hot water (120-140F) vs. a cold winter day (< 40F).

    Also, for domestic hot water, you'd only use one or two panels since the volume of water is very low while for the pool you need an area of panels that is large, usually at least half the surface area of the pool if you want reasonable heating.

    Since your concern is primarily about getting more heat during the cooler weather, then I'd suggest looking at the glazed panels since these will still be efficient during the summer peak but will also be more efficient for pool use (though not necessarily for domestic hot water) than evacuated tube during the spring and fall. The glazed panels are roughly 3 times as expensive as flat mat and evacuated tubes are roughly 2 times as expensive as glazed panels. If you wanted some domestic hot water heating, then you could get separate evacuated tube panels for that if you wanted to for that purpose. Just note that the efficiencies I listed in the link Jason gave were for direct heating and did not include losses from a heat exchanger which is often required for some panels to minimize corrosion.

    Richard
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Solar Pool and Hot Water Heating

    Hi Richard, thanks for your replies, trying to get this all figured out. In the East Coast of Canada, June and September can be nice during the day, then goes down to around 40 Degrees at nitem during days it can creep up to around 80. Those specific days are when I want to have the pool warm. I am thinking an electric supplemental heater or Natural Gas might be the correct route to go. I have also looked into building one of those redneck pool heaters, a buddy of mine did one, and he can get a 20 Degree jump in pool temp over a 32 hour period an it costs him $22 worth of propane.

    NOt really sure what route I want to go.

    Hate to see that water there and not being used, and know it would be if the water was warmer.

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