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Thread: Solar heater or no heater at all?

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    Join Date
    Nov 2013
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    Solar heater or no heater at all?

    I've read so many threads on this topic! I would appreciate confirmation of the information I have collected so far...

    At this point, I have narrowed my options to purchasing a solar bubble cover and maybe adding a solar heating system.

    I put together the following information based on the format and links posted by others (Chemgeek?) on this forum.

    location: Miami

    Jan Feb Mar Apr May June Jul Aug Sept Oct Nov Dec
    Avg High 74 76 78 81 85 87 88 89 87 84 80 76
    Avg Low 55 57 59 62 68 72 73 73 73 69 63 78
    Avg Rain (inches) 2.14 2.45 2.91 3.01 5.34 10.07 6.8 9.7 8.99 6.69 2.97 1.62
    Solar panel tilt (Kwh/m2/day) 3.5 3.5 3.5 3.5 3.5 2.5 2.5 2.5 2.5 2.5 3.5 3.5
    Gallons in Pool Pounds target temp Total BTUs FPL cost heat pump output hours to heat
    19152 158,962 85 F 2,384,424 .09 - .11 per Kw 133,000 / 140,000 18 hrs / 17 hrs.


    As I understand it:
    1. With only a bubble cover, I can expect to achieve and maintain a pool temperature that is equal to the High temperature for the day. If I want to swim in 85 degree weather, I can swim from May - October. Is this correct?

    2. To swim in the other months, I will need to use a heater. To calculate how long it would take to raise my water to the temperature I want, I calculated the number of BTUs I will need to raise my water 15 degrees (the greatest increase needed during the months outside my range). How does this relate to the solar panels? Do they have BTU output equivalents?

    Am I on the right track here? My PB is suggesting a 140,000 BTU heat pump for ~$5,000. For solar panels, I'm told it will be roughly the same cost. Seems like solar panels would be the better option.
    Swimming!: 19x32 IG rectangular pool, 22,500 gallons; 3' - 6.5'; open spa w/ 6 jets; raised wall w/ 1 sheer descent and 2 minijets, 2 color-changing LED pool lights, 1 spa light; Jandy 2 1/2 HP 2 speed Pump, Jandy cartridge filter (320 SQFT), Diamondbrite Cool Blue

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    Mod Squad jblizzle's Avatar
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    Re: Solar heater or no heater at all?

    1. I am not sure about getting the water to the high temp of the day. Solar covers are generally more about heat retention (especially at night). If you do not have a lot of wind, then you will actually increase the pool temp more without a cover when the sun is shining on it. If it is a hot cloudy day, you may not be adding much in the way of heat at all and just hoping to reduce losses.

    2. Solar panels (in optimum orientation and full sun) generate about 1000 BTUs per sqft per day. You need about 160k BTUs to raise the temperature by 1 degree. So if you have a 320 sqft solar array, you should add about 2 degrees per day from the panels. My pool is a little smaller and I have 500 sqft and have seen the pool rise 5 degrees in a day (that includes the solar panels and sun hitting to pool etc). Right now my solar is only running a few hours per day to maintain temp in the upper 80s.

    Solar is nice because the heat is free (after install), but have realistic expectations. You are not going to get a lot of heat quickly, clouds and rain mean no heat added that day. An automatic controller is a VERY good idea so you do not cool water when a storm rolls in.
    Jason, TFP Moderator
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    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    Isaac-1's Avatar
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    Re: Solar heater or no heater at all?

    Like Jason said, you must have realistic expectations of solar performance, this means you can't decide that you suddenly want a warmer pool tonight, it is much more realistic to decide you want to pool to be warmer in 3 or 4 days. The same holds true of desiring an exact temperature instead of a temperature range. Also as you noted up front cost for solar is similar to a heat pump, but operating cost will be much less, another nice benefit of solar is it can be used as a pool cooler by running at night and during rain storms during those hot summer days when your pool may be uncomfortably warm.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    Re: Solar heater or no heater at all?

    Thanks for your responses. I need to read it through again to absorb this information.

    For the solar bubble cover, if I only cover the pool at night, I am preventing heat loss and maintaining the temperature of the pool that is achieved during the day. With this method alone, the water will never be much warmer than the outside temperature?

    With the solar panels (thank you for the BTU number!), I need to calculate the square feet of the installed panels to determine the degree of rise in temperature I can hope to achieve in any given day. For a pool with 648 SF (mine) and 500 SF of panels, I can estimate about a 5 degree rise in temperature in ideal conditions.

    In contrast, with the heat pumps, I can achieve a more rapid rise in temperature, but at a greater expense. If I use the heat pump to reach my ideal temperature and then place the solar bubble cover at night, will I be able to maintain the pool temperature?

    Am I understanding this correctly?

    It's a good advice that I should consider how I want to use the pool. If I don't plan ahead (by 3-4 days), I won't have the pool heated to temperature I want with solar panels. Even a heat pump requires planning ahead by at least 1-2 days...
    Swimming!: 19x32 IG rectangular pool, 22,500 gallons; 3' - 6.5'; open spa w/ 6 jets; raised wall w/ 1 sheer descent and 2 minijets, 2 color-changing LED pool lights, 1 spa light; Jandy 2 1/2 HP 2 speed Pump, Jandy cartridge filter (320 SQFT), Diamondbrite Cool Blue

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    Isaac-1's Avatar
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    Re: Solar heater or no heater at all?

    Generally with solar panels you set your desired temperature and leave it there, you don't turn it down when not in use, as during marginal conditions they can take weeks to reach their desired temperature goal. Think 3 steps forward during the day then 2 steps back each night. Having said that in your climate it is possible to manage 12 moth pool operation with solar heat alone. For some good general solar advice I suggest doing some reading at http://h2otsun.com/ while it is slanted towards there products, there is still a LOT of good generic information mixed in.

    Ike
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

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