Water Temp

[CarlD]

Running solar panels at night is nice and simple. They act like a car radiator.

[rdietman]

wouldnt pushing the water through all that small diameter pipe cause some pump head problems??????

[duraleigh]

wouldnt pushing the water through all that small diameter pipe cause some pump head problems??????

If you don't use enough of them, yes. The seven 3/4" pipes is slightly more cubic volume than the 2" pipe feeding them.

I need the multiple pipes for the increased soil contact for heat dissapation and am willing to trade off a little TDH to get it. I'm thinking it will add about 2-4psi max to my pressure.

Dave S.

[jcpbnp]

Thanks for all the information. I'm not sure I understand how solar panels work but was is the approximate cost of having them installed?

[CarlD]

Thanks for all the information. I'm not sure I understand how solar panels work but was is the approximate cost of having them installed?

It's very simple....A large flat black plastic panel has lots of little tubes running through it. Pool water is pumped in one side, cools the panel, and is pumped out the other side, back into the pool, carrying the heat it leached from the panel with it. Think of how hot a black, asphalt road gets--it will burn your hand. The panel would get that hot too, but all the water flowing through bleeds off the heat and keeps it cool enough to touch, sometimes even cool, even on the hottest days.

The more water you can flow through that panel, the more heat you can bleed off into your pool. It's a matter of transferring BTUs, not temperature. A BTU (British Thermal Unit) is the amount of heat energy necessary to raise one pound of water 1 degree Farenheit.

Its metric equivalent is the calorie (actually kilo-calorie) and, yes, it's EXACTLY the same calorie as used in food and dieting. A (Kilo-) calorie is the amount of heat energy needed to raise one kilogram of water 1 degree Celsius. They actually burn the food to measure the caloric output...

A solar panel works EXACTLY like your car radiator works, only backwards. Your radiator takes the hot water from the engine and exposes it to cool air, cooling the water and keeping the engine from melting. So if you run your solar panel at night, when it's cool, it will cool your pool (if the pool's too warm) in EXACTLY the same way.

I don't know the cost of installation. I've only installed them myself, or had them as part of the pool's installation (FantaSea pools). I suppose it depends on how fancy you want to get. A roof-top system that's winter-proof, with bleed valves and computations of how much pump pressure is needed is going to cost a heck of a lot more than having a guy just set up roll-up panels on the ground and plumb them in.

[prh129]

I don't know how effective this would be but should be inexpensive enough to try. Suppose you get a large white tarp, cut it to size and use it as an anti-solar cover? It should reflect most of the sunlight when its in place. If it works, you could market it! (unless someone already has).

Peter

[PoolDoc]

Suppose you get a large white tarp, cut it to size and use it as an anti-solar cover?

The problem, as with solar covers, is the need to wrestle them on and off 2x daily. From what I've seen, about 75% of cover purchasers end up parking them in a corner for a year or so, before they give it up, and toss them.

A thin white poly cover would be harder to handle than a solar cover. A yet more effective silver Mylar cover would be even worse to handle, and all but impossible in even a slight breeze. An aluminized automatic cover might be cool, though.

Ben
PoolDoc

[WagonPilot]

A solar panel works EXACTLY like your car radiator works, only backwards. Your radiator takes the hot water from the engine and exposes it to cool air, cooling the water and keeping the engine from melting. So if you run your solar panel at night, when it's cool, it will cool your pool (if the pool's too warm) in EXACTLY the same way.

Not to pick a nit, but it's not EXACTLY the same. The car radiator (dispite its name) is actually utilizing convective heat transfer, while running the solar panels at night is primarily a blackbody radiation transfer.


James

[CarlD]

Yup, that's a nit. The car radiator uses radiation--and the fan moves it away when the car is idling.

Still, it DOES function at night in a similar fashion...

[dalparadise]

I live in Houston and have similar water temp issues, as you might imagine.

The best thing I've found is to avoid running your pump at the hottest point of the day (or at least when the sun is directly overhead) -- 12-3pm, or so. Note that radiant heat from the sun is much more effective in heating your pool water than air temp. So, even though it's usually hottest here in Texas around 5pm, or so, the sun is not directly overhead.

My pool is on the north side of my house, so the sun tracks across it all day long in summer. I got 94 degrees every day in July.

Toward the end of summer, I planted some 8' Mexican fan palms on the western edge of the pool to cast long shadows after 5pm. That has helped.

With night filtering and some shade, I'm thinking I'll get 91 degrees this summer -- which is enjoyable for me.

Good luck!