How long to heat pool?

[vimfuego]

Hi All,

First time pool owner here and the weather is starting to get hotter over here now so it's time to take the solar heater out of Winter mode (I think). The solar heater is currently reading about 40degC (100F) up on the roof and the pool is currently 16degC (60F). I don't know how much water the pool holds but it's about 10M (32ft) x 3M (9ft) and I'm guessing about 2M (7ft) at the deep end. The solar pump is rated at 280 Litres Per Minute (4438 GPH).

So I am just wondering, if we have a run of days with warmer weather, how long might it take before the pool gets up to say 22DegC (72F)? (The pool has no cover)

Thanks,
Ross

[PoolDoc]

Pool temperature rise = mass of water x (heat added by solar heater + heat added by sun on water - heat lost by evaporation - heat lost to conduction (dirt) - radiative heat loss at night) . The ONLY one of those 5 factors that can be easily determined is the mass of water in your pool (~94,000 lbs or ~43,000 kg).

That's a long-winded way of saying, I don't know the answer to your question, and can't calculate it -- even if you gave me all the relevant weather data, your latitude; the surface area of the solar collector; the circulation set up on your heater; your ground temperature, and more.

The BEST way to answer the question is to try it and see . . . if you keep some records, after a couple of years, you should be able to predict heat rise your self.

[Spensar]

The biggest step you can take is getting a cover for your pool. It will speed up the process considerably.

Taking a look at a weather map for Australia, it shows about a 10 degree celcius difference between daytime highs and night time lows. Without a cover, you are losing most, if not all, of your heat gain during the day. That will apply when your solar heater is active as well.

You have a good sized 32'x9' pool, and without a solar cover, when the air temperature is lower than the water temp it is a 288 sq. ft. evaporation pan. Wind will also accelerate the heat loss. Kinda like trying to heat a house without insulation, or even a roof.

Good link here on pool covers. http://energy.gov/energysaver/articl...ng-pool-covers

[PoolDoc]

Thanks, Spensar

[CarlD]

OK, I'm gonna shoot from the hip here: If your solar heater's surface area is at least 1/3 to 1/2 your pool's surface area (or equiv), you can count on a few days to get the water warm, anywhere from 3 to 7 days I'd guess.