Advice needed on Pool Pump with Solar Panels Installed

[amardesai]

Hello Experts -
I need some advice.
I have an Inground pool that was built in 1968. The plumbing is all original, and believe it is 1 1/2" copper. This is from the skimmer and the bottom drain at the pool. There are two returns.
The piping where the filter and pumps are is 2 inches.
I have just installed the coil ring Solar Pool heater system. I have about 20 of those coils (Gull Brand). They are mounted on the roof. Roof is about 25 Foot and 45 degree pitch.

The Problem I have is that when I have Solar Diverter Closed (water is not being sent to Solar Panels) the pressure on the filter is 10 PSI. With the Solar Diverter on it will jump to about 20-21 PSI.
Reading on the blogs I see that it could be my pump; my pump is 1 HP currently

I'm considering getting a Intelliflo pump. That is variable and hoping should be powerful to achieve the flow rates.
Also, my SOLAR piping is about 2" and 2 1/2" (in some lengths).

The reason I want to get a better pump is to see if I can get my pool heated faster or efficiently. After a full day of running I'm getting a 12 Degree increase and that is on a 90 degree weather. I can't achieve 90 degree pool. Max I have gotten it is 85-87 degrees. I feel I should get more. My Sisters place which is about 10 miles away gets about taht much and has to limit it from getting hotter; (he has the ribbed/mat solar panels).

So the question I guess is what can I do to get the best performance out of my pool in regards to heating with Solar, and if my current plumbing setup is a limiting factor.

Thanks in Advance.

 

[kevinskii]

Hello. I think you're correct that a 3HP pump like the Intelliflo is likely needed to maintain recommended flow rates on an adequately sized solar array.

However, even with a more powerful pump I am somewhat doubtful that your solar coils will be able to deliver the heat you expect. The Gull Sun Coil website recommends 5gpm per panel. With your 20 panels that's 100gpm, which is probably not attainable with most residential pumps. For reference, my Intelliflo pump has to run at around 2400rpm to maintain the recommended 45gpm through my array of nine 4'x12.5' mat-style panels. Judging from the Gull Solar pictures I've seen, the mats are also almost certainly able to facilitate a much higher flow rate per unit of pressure than the coils could.

This TFP thread has some good discussion on the mat versus coil solar arrays. It's from 2013 but the basic principles haven't changed. Hopefully I'm wrong about this, and your coils will end up working just fine. I'll keep an eye on this thread to learn what the real experts on here have to say.

 

[Pool_Medic]

Interesting solar system for sure, id love to see a side by side comparison with traditional panels. Less sq footage to me says not as efficient at drawing the heat.

 

[amardesai]

Hello. I think you're correct that a 3HP pump like the Intelliflo is likely needed to maintain recommended flow rates on an adequately sized solar array.

However, even with a more powerful pump I am somewhat doubtful that your solar coils will be able to deliver the heat you expect. The Gull Sun Coil website recommends 5gpm per panel. With your 20 panels that's 100gpm, which is probably not attainable with most residential pumps. For reference, my Intelliflo pump has to run at around 2400rpm to maintain the recommended 45gpm through my array of nine 4'x12.5' mat-style panels. Judging from the Gull Solar pictures I've seen, the mats are also almost certainly able to facilitate a much higher flow rate per unit of pressure than the coils could.

This TFP thread has some good discussion on the mat versus coil solar arrays. It's from 2013 but the basic principles haven't changed. Hopefully I'm wrong about this, and your coils will end up working just fine. I'll keep an eye on this thread to learn what the real experts on here have to say.

Hi Kevin -
Thanks for the Input. I'll take a look at the thread you mentioned. In hindsight I wish I stuck with the mat style; however, I have all these vents on my roof and SoloTubes(sun tunnels) so the coils seemed like a good choice, but I wish I had come to TFP before making that decision.

I think with with the current 1HP single speed pump I have now; it may be better, but a huge investment just to see if it helps get the temps up.

Thanks again. I'll send an update on what I ended up doing.

 

[amardesai]

Interesting solar system for sure, id love to see a side by side comparison with traditional panels. Less sq footage to me says not as efficient at drawing the heat.

Yeah. I had bought this system thinking that I can get them installed with more sq ft. I have about 580 sq ft of pool surface. I think I have about 30 sq ft per coil X 20 coils is about 600 sq ft.
which I thought would be more than sufficient;
I have this sun tunnels and vent pipes that make it hard to put the mat style. Although I was reading that I could have some different sizes and put them as seperate systems.

 

[dschlic1]

I have a 1 1/2 Hp two speed motor with solar panels. It does fine. With a string of 7 sunny days, my pool temp is about 10 F higher than the highest avg temp during those seven days. I do not try an force the full discharge of the pump through the panels, rather I adjusted the solar heater control valve so that the increase in filter pressure was close to the recommended pressure across the panels.