Solar Heater Efficiency

[curtisgillard]

Hello
I have an old solar heater setup on the roof of the garage to heat our pool water. The 6 panels are plastic, and each looks like a big manifold, with 2.5 inch pipes top and bottom, with maybe 20 1" pipes connecting the top & bottom pipes. It works, but even on the hottest, sunniest days the water coming out of the jets is lukewarm at best. I would like to increase the efficiency by rearranging the panels so they flow in series with each other. Currently they are connected in parallel. I am sure the temperature of the water at the jets would increase, possibly dramatically if the panels flowed in series, progressively heating the water to a much higher temperature.
Can anyone see a problem with my idea?
Thanks!

 

[CJadamec]

There's nothing wrong with your set up. Solar heaters are not ment to have large Temp rise across the panels.

Solar heat is a slow and steady wins the race type of heater.

What you are asking for is actually trying to decrease the efficiency of your panels.

 

[curtisgillard]

Thanks for your reply! I do appreciate it. I'm trying to get it up to a nice temp quicker for my wife to enjoy it.
If I understand correctly, you mean that higher temperature but lower flow (due to restriction) ends up taking just as long to actually warm up the pool.... Good point.
I initially felt the size of these manifolds would not present much restriction to flow, even in series....
But now you've got me thinking! Might not be worth the work.
If I do try it, and there is significantly more restriction, I suppose I should see that on my pressure gauge.
Hmmm....

 

[Donldson]

If I understand correctly, you mean that higher temperature but lower flow (due to restriction) ends up taking just as long to actually warm up the pool.... Good point.

No, it would take longer.

Try thinking of it this way: you aren't trying to warm the pool, you're trying to cool the panels. The cooler you keep the panels the more efficient they are. If any plan you put in to place causes the panels to get warmer (and as a result, the water at the return being warmer) then you are dropping the efficiency and causing your pool to heat more slowly.

 

[curtisgillard]

Ok, understood. Thanks for saving me a bunch of work.
Wife will have to be patient.

 

[Pool_Medic]

30,000 gallons is a lot of water to heat up. 6 panels might get you an 8-10 degree bump on a sunny 85 degree day provided your panels are properly aligned to the sun.

 

[sktn77a]

That setup would be fine in southern US states. In Canada, though.... sounds like it's working as well as can be expected.

 

[CJadamec]

No, it would take longer.

Try thinking of it this way: you aren't trying to warm the pool, you're trying to cool the panels. The cooler you keep the panels the more efficient they are. If any plan you put in to place causes the panels to get warmer (and as a result, the water at the return being warmer) then you are dropping the efficiency and causing your pool to heat more slowly.

What he said.

Next best thing you can do is add automation to the solar panels so that pool water only runs thru them when the sun is shining. Solar panels will cool your pool off just as well as they warm it up when run at night or on cloudy days.

Also if you don't already have one a solar cover for the pool will prevent heat gained during the day from being lost at night. If you want a warmer pool keeps it covered when you aren't swimming in it. In the early summer and fall my pool has a bubble cover on it 99% of the time.