Solar panels plumbing efficiency

[chazalicious]

I've got a pair of above ground solar panels, and I'm trying to figure out the most efficient way to plumb them. I have hard pipe running from the pump to where the panels are set up on a frame on the lawn. They're the kind of panel where the water flow is out and back within the same panel. Last year, I used flexible hose to connect them in parallel. That was a massive pain because of the t-junctions, and I fought with all the hose connections all summer.

This year, I want to hard plumb them. The complication is that I want to be able to take the panels down during the off season, so I need to be able to take the whole thing apart. The only way I can figure out to do that involves including something like 4-6 unions, in addition to all the elbows and t connections, but that would let me keep running them in parallel, which I know is more efficient. On the other hand, if I plumbed them in serial, the plumbing would be much simpler, with far fewer turns involved.

So is it actually worth continuing to run them in parallel, with the more complex plumbing, or would the simpler plumbing from running them in serial cancel out the advantage of running in parallel?

Equipment-wise, it's 1.5" PVC plumbing all through the system, and the panels are a pair of 2'x20's that have the inlet and outlet on the same edge, and they can't (as far as I can see) be configured so that it runs one direction only, rather than going out and back. Running them in series would have to send the water out and back through both panels before returning to the pool.

 

[mas985]

So you are really comparing an effective panel of 4'x40' vs an effective panel of 2'x80'. You will lose some in both thermal and electrical efficiency but I suspect it won't be that much. I would just run an experiment and see if the series installation creates much of a thermal non-uniformity over the panel. Do you have a IR thermometer you can use? Otherwise you can do it by touch.

But in some of those types of panels, you can remove the center diverter (i.e. a plug) so that water won't do a round trip in the panels. Does yours not have that? If you remove the plug, then the effective panel is 8'x20'.

 

[chazalicious]

From what I can tell, the diverter is permanently fixed in the ends. The only way to get it out would be to get a long bit and try to drill it out, but that'd be dicey as all get out. For clarity, it's two panels that are 2'x20'. I'm guessing that with a setup that small, the difference between the two setups is actually negligible.

Maybe one of these days we'll think about getting a properly-sized solar heater setup installed on the roof, but these two panels were free, so that's what I'm using for now.

 

[mas985]

What is the make/model of the panels?

 

[chazalicious]

If I remember right, it's a SunHeater S421 kit, single box.