Using old rooftop solar water panels to heat pool.

[Paulk]

have a 13,500 gallon AG pool I installed last year. All has gone really well, with the advice from a member here. I’d now like to raise the temperature of the pool a few degrees. Last year, in the middle of the summer, from July thru August, the pool stayed in the mid to high 70’s on average. The high 70’s was fine, but it would be nice to get it a bit higher on average. I have older copper solar collectors, fully glazed that I’m not using. Each panel is about 4’ by 8’, (perhaps a little less) so in total I have reasonably high quality collectors available for free that have a surface area of about 120 square feet. My pool currently is not a salt pool, I use a chlorine injector. (I’m off the grid so opted to go this way to save power).
My question is, can I use these older copper collectors to heat, or help heat my pool, without experiencing problems with the copper metal in the system? I know I could get new “poly” or some synthetic panels that would have no reaction, but wondered if using the copper panels was bad? Any thoughts?

 

[ogdento]

The chlorine will eventually destroy the copper, but it may take some time depending on how thick the copper pipe is (an old house had some thin type "M" copper pipes that were badly corroded from the city water supply... the "L" type is thicker and just takes longer to corrode away)

 

[ogdento]

apologies, I may be wrong... i was just thinking about old water pipes, but it seems other chemicals in the pool water may prevent corrosion. see this tfp post:

Copper and Chlorine

Boy did I mess this up! in trying to delete the multiple posts, I managed to delete the whole thread! So Sorry! Here it is: Sat Sep 08, 2007 11:50 am I am looking for some info regarding chlorine levels and there effects on copper piping. I am going to install a fiberglass pool this...

www.troublefreepool.com

 

[Paulk]

Thanks for the reply. yes, the pipes too and from the panels would be PVC, but agreed, the gauge of the copper itself in the panel is fairly thin. But if destruction of the panels themselves is the only downside, then I think I might use them. They are not worth much to me otherwise. I was more concerned that they copper salts or whatever might make my system much harder to maintain PH or CL levels. If that were the case, I'd just opt for buying some new non-reactive panels.

 

[Paulk]

Ah, so you are saying that the copper and Chlorine might indeed make for problems. I'll read that.

 

[ogdento]

Yeah, at first I thought there wouldn't be any problem except possibly premature corrosion of the pipes in the collector, but after reading that other post I started wondering if it might foul up the water... but I'm not a chemist!

what about using your collectors to heat a water/antifreeze solution and run it and the pool water through a stainless steel heat exchanger of some sort... so the pool water is totally isolated from your collectors? i've always wanted to try something like that

 

[Paulk]

Yes, one can do that for sure. My neighbor on a ranch next to mine does that, but that is a considerably more expensive system. I think I should just go get some of the poly panels. Anyone have a good idea of which ones work best?

 

[swamprat69]

Copper is at over $2.50 a pound...it might help defray the cost of the new panels!

 

[Paulk]

True, copper has some value. But the bladder on a panel is pretty thin. I sort of doubt that there is more than 20 lbs per panel, maybe 1/2 that. Not to say worthless, but not a huge amount. I used to use these 4 panels to keep a hot tub hot. Worked very well, kept the water at about 125 in the summer, (too hot obviously, but I just added cold water when I wanted a tub, which I had plenty of from a spring) but it worked obviously when it was hot out, so in the summer. Not so well in the winter, when I liked a hot tub.
I'm not too concerned about destroying the panels, as I said. More, I was concerned about the effects on the pool chemistry. It seems that since I do use cyanuric acid, but do keep the PH up to mid 7.4 or so, that I might be fine using the panels for a few years. I'll have to consider it. Another good thing is that I have pretty much as much water as I want, for free, so if there was some bad chemistry, I can always empty the pool and refill it pretty quickly.
thanks a lot. Below is a picture of the pool. 24' across, deck is 42'x44'. Almost done, just have to add gates.
pk