On a travel forum I frequent, one of the posters mentioned he was using " evacuated tube solar panels" to supplement the natural gas heat he uses in his pool. I asked him about that type vs. the "normal" black plastic tube type and the advantages, etc. He didn't have much knowledge of the pros and cons, but said this:
To be honest I am not sure about the relative pros and cons of the two types. I think the ones that you have may be a bit cheaper and less fragile. With mine I can't direct the water flow to the panels during the day as if water is sitting still in the panels get super hot and if you push cooler water through them it can cause the glass tubes to shatter. So given these drawbacks I am guessing that the glass tubes must be a little more efficient at heating otherwise no one would use them.
Last year was the first year that we had them and the installer said that six panels said that six panels should be enough to keep the pool at 84 without using gas. It was a very cool summer so that didn't quite work - we still did use our gas heater to keep the temp in the mid 80s.
I asked him if he used a floating bubble cover and night and he said he didn't (!!!!), so maybe that's why he wasn't able to maintain the temp he wanted (although it might have been the cool weather).
Now here's the kicker - - - - He lives in TORONTO!!!
So my questions are:
1) Does anyone know anything about this type of solar heating? (it seems like it must pump out a lot more heat than the traditional ones)
2) What's the deal with the "can't direct the water flow to the panels during the day as if water is sitting still in the panels get super hot and if you push cooler water through them it can cause the glass tubes to shatter" statement? Does that just mean you have to run it all day instead of turning it on for the first time at noon when the tubes are super hot compared to the water temp?
3) Is it worth looking into replacing my current system with one of these?
My system works fine, but it doesn't do so great on the ends of the season when we need it most (especially for my wife who likes the pool WARM!). I'm just wondering if a guy in Toronto is getting good results (without a cover) then could I do much better being much further south with these evacuated tubes?