Sunheater Solar Panels in parallel?

Jul 29, 2016
20
South Jersey
I have a set of 2 2'x20' panels on my garage roof. I have another set of 2, but would like to plumb them in parallel to increase flow.

I talked to someone at smartpool and they didn't grasp my theory that parallel would increase my flow back to the return instead he said I'll lose heat because each panel builds temperature. I know that but each panel is metered to control the flow rate, so it doesn't make much difference if they are gathering heat at the same rate.

Well the 2 panels in series work well now, just low flow, so if I double the loop I should get about 8gpm instead of 4gpm, correct? Here's the layout. Will I have issues with even dispersion to the top and bottom loop or will it be close once it's running? I also am not sure how to cross over on the bottom hot return. 4 90 degree elbows and go over?
c279cf0b869a66dbdda4d74568d3833d.jpg
 
What you propose will work fine. In fact it will work better than if you plumbed them in series.

As long as you have sufficient pressure to the panels, they will all balance out in respect to flow.

If it were me, I'd parallel all four panels to get the most flow and therefore the most increase in heat.
 
This confuses my simple mind. How does this increase the flow rate (gpm) through the line?
And if it does then it does. I'd really just like to understand this better.
It is certainly counter intuitive to think that adding additional panels, with the same 4 gpm restrictions, will increase the overall flow rate.
Can you help me understand this?

44,000 gal. IG, Hayward Maxflo vs, Tagelus T60 sand filter, Taylor test kit 2006C, diy solar panels for heating pool water, full size solar blanket (to keep the heat we get), a Pentair Easy Touch 4 & the Pentair IC60 swcg
 
Ok. I understand reduced resistance. 2 years ago I re-plumbed all lines leading from the pool to the pump. Could not find our leak anywhere else so i rented a trencher and dug up the back yard and cut the concrete to the skimmers. I replaced all 90 deg elbows with 45's and saw an increase in flow through the system. Much for the same reason, less resistance. I hadn't considered the reduced travel (and less resistance) in scootchu's system.
Thanks for the help!


44,000 gal. IG, Hayward Maxflo vs, Tagelus T60 sand filter, Taylor test kit 2006C, diy solar panels for heating pool water, full size solar blanket (to keep the heat we get), a Pentair Easy Touch 4 & the Pentair IC60 swcg
 
Actually two 45 degree PVC turns add more resistance to the flow than one 90-degree turn, although the difference is fairly negligible. So there must have been something else that resulted in your higher flow rates.
 
I added 1 45 degree fitting at the cross over. I tilted the T and spun the 90 coming out of the panel. Worked great.

My theory is your flow is limited to your weakest link, before the panels it was the 1.5" pvc. When diverted there was your normal heavy filter flow.

I added 2 panels in series, both rated for 4 4gpm. Now my weakest link was the panel. No matter what I'd get no better than 4gpm. Now add a second loop onto the same 1.5" which is capable of a higher flow rate and now you have 2 sets of 2 panels each rated for 4gpm, theoretically passing a total of 8gpm. I may try to plumb each on their own loop.
 

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Plumbing does not work like that where there is a "weakest link". There really is no maximum flow based on a single restriction. If you add more pressure you will get more flow.
 
This is the way I would do it, implementing a reverse return loop, eliminating any need for a balancing valve.

panels1.jpg
And of course there is this option as well, also incorporating the reverse return loop.

panels2.jpg

Boyle's law states p1 X v1 = p2 X v2. So as your pressure goes up your volume will go down and visa versa. But removing any bottleneck will reduce internal friction and improve flow.
 
What I was trying to say is that you are not limited to 4 gallons per minute through one panel. If you add more pressure you will get more flow than that.

In your example of draining a pool with one hose or two hoses the pressure is constant and yes you will get more flow through two hoses. But if you added enough pressure you could get the same amount of flow through one hose.
 

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