Solar Panel Install w/pcs Part 2 (dial-up beware)

[CarlD]

How many square feet of panels do you have???

I have 640 square feet of pool and heat them VERY nicely with 240 square feet of panels. During the heat wave my son forgot to turn them off and the water hit 98 degrees!

Why do you need so much? Are you in Northern Alaska and looking to extend your swimming season beyond the 4th of July?

[tphaggerty]

Two comments:

Drain back is NOT just for "winter freeze protection". It is designed to take a HUGE load off of the panels and your roof when the panels are not generating. If you took a 2 liter soda bottle, filled it with water, attached a hose filled with water, stuck the end in your pool and lifted the bottle, at some point, the bottle would collapse due to the pressure created by the water trying to go down! The same forces are present in a closed solar system - the higher you go (2nd story like mine), the more pressure. Letting the system drain back is like punching a small hole in that bottle, the water drains back, the pressure is relieved and your bottle (or in the real world, your expensive solar panels) DON'T collapse. So, as discussed above, your pump needs to be able to lift water to the highest point in your solar system, in my case that is about 35 or so feet.

As for more is better. I have 55% coverage (450 ft on an 800 ft pool) and would like more. Two reasons, my panels face slightly northeast (only place on the house they could be put), so they generate wonderfully when active, but they are active probably 2 hours a day less than if we had an optimum south/southeast exposure. The 2nd reason is recovery time. When we get a very cold night (we have had nights into the high 40s, low 50s here in lower NY), the pool loses a lot of heat (we don't cover it in during summer, I know that is a big part of it). We can recover about 4 to 5 degrees per day on most days. If we added 50% more panels (maybe on the garage, next year), we would get 6 to maybe 9 per day. That lets us recover from a really cold night or a cold rain storm in one day, instead of 2 or 3. That would be NICE.

Simons99, I think you are fine. You will have 80% coverage, so even on a north/west facing exposure, you should have great generation. That is about the percentage I hope to get to next year by adding a 2nd set of panels of the garage roof.

Don't get me wrong, I am THRILLED with our solar, we shut the system off when we were getting water at 90 consistently. Its just that with the weather so variable here in NY, I think quick recovery time is probably more important than in other areas of the country.