Too many solar panels?

[big_g]

Well, I finally got around to getting all my solar hooked up and running. I went up on the roof and felt my panels at the end of the run and they are still warm to the touch. Not hot, but not cool like the ones at the start of the run.
My question is, is there such a thing as having too many solar panels hooked up?

I have a 15,000-18,000 gallon pool. Pump motor is 1hp I think. PSI with solar and a little bit dirty filter is about 18 (usually runs ~10, 15 when filter is real dirty).
I have 8 4x8 Heliocol panels. They are 1.5" on the main headers, as is all the rest of my pool plumbing. Panels on single story, pump at ground level.
Water coming out of returns is definitely warmer, but not as warm as I expected it to be.

Thanks for any help!!

 

[chiefwej]

Ideal is solar panels equal to 80-100% of the surface area of the pool. At least that what Heliocol said when they designed my system.

 

[peterdaly]

If it's a parallel setup, your warmer panels are not getting as much flow as your cooler panels.

Water coming out should not be hot. Slightly warmer is actually ideal for heat transfer. You are probably heating 44 gallons per minute by that amount...which is actually a lot of heat if you are getting a few degree lift.

If you can balance flow better, that may help a bit. 8 is probably not to many panels, and is a fairly typical setup.

 

[jblizzle]

How are they plumbed? Can you add a picture?
I have an idea about how this could happen ... but really they should all have uniform flow.

 

[big_g]

How are they plumbed? Can you add a picture?
I have an idea about how this could happen ... but really they should all have uniform flow.

It's dark out now, but the panels are plumbed in two sets of 4. All in parallel. I suspect that there is not enough water coming in to fully fill all 8 panels, so I was wondering if turning off the second set would actually make more heat by causing the water to flow better through the first 4? (Seems totally counter-productive, but I just thought I'd ask).

 

[jblizzle]

Well, that still does not answer my question. How are they in parallel? Where are the fed and where does the water leave them?
I doubt only running half would be an improvement.

 

[PAGirl]

Where are you located?

 

[big_g]

I apologize. They are plumbed in series, not parallel. And the panels are 4x12, not 4x8. My house AC went out two days ago, so I'm half crazy from the heat...

I'm in Tucson, Arizona.

Here is a very high quality drawing...

 

[jblizzle]

Those are in parallel, but they are not plumbed correctly. I assume the ones on the left were cool to the touch and the ones on the right were the warmer ones ... right?

Who did the install? Because there is at least 3 problems I see.

1. Are you sure that the panels are fed on the top? They should be fed on the bottom and then the water travels up the panels.
2. The panels on the right will not drain completely automatically. If there a drain in the lower right corner for the winter?
3. The reason the panels are not balanced is because the water will take the path of least resistance. In this case it is easier for the water to go through the left panels than to travel further and go through the right panels.

If I were doing the install (or redoing it), I would feed the panels at the lower right corner (so you would have to add a pipe that travels all the way below the panels and then hooks in at the lower right. Then the warm water would leave the solar from the upper left corner (with the top pipes left as they are drawn). That way the water has to travel the same distance through every little tube in every panel.

 

[big_g]

Those are in parallel, but they are not plumbed correctly. I assume the ones on the left were cool to the touch and the ones on the right were the warmer ones ... right?

Who did the install? Because there is at least 3 problems I see.

1. Are you sure that the panels are fed on the top? They should be fed on the bottom and then the water travels up the panels.
2. The panels on the right will not drain completely automatically. If there a drain in the lower right corner for the winter?
3. The reason the panels are not balanced is because the water will take the path of least resistance. In this case it is easier for the water to go through the left panels than to travel further and go through the right panels.

If I were doing the install (or redoing it), I would feed the panels at the lower right corner (so you would have to add a pipe that travels all the way below the panels and then hooks in at the lower right. Then the warm water would leave the solar from the upper left corner (with the top pipes left as they are drawn). That way the water has to travel the same distance through every little tube in every panel.

Haha, I installed them. Just tried to match the way the guy I bought them from had them. But you make great points and now I feel dumb for not thinking of them before. The only thing I did think of was a drain for the winter.

I'll try and redeem myself by saying that I did a good job on the actual plumbing. It all looks very nice and orderly. It is just all wrong apparently, haha. But that is why I joined this forum...

Ok, how about this:

Should be a very easy fix.

 

[jblizzle]

No worries about the install ... did not mean to offend if I did, but I would be surprised that Helicol would have done them this way

I can hardly read that picture .... To post more/larger pictures, you either need to raise your storage allotment by Becoming a TFP Supporter or follow the How To Post Pictures tutorial.

That might be correct, nut not ideal. Hard to suggest without seeing how the roof is laid out. I would rather see the supply pipe run along the bottom past all the panels and the the highest point of the exit be at the upper left to ensure everything fills. This may require you switch the location of the 2 pipes running from the pump to the panels (I had to cross mine due to how the previous owner did their junk of a DIY system). Do you have a Vacuum Release Valve?

Here is how I did mine (without the "high loop" I show on the left) which is not perfectly balanced because the water path is shorter through the left panels, but I do not notice a temp difference. I think having the highest point above both panels makes the panels want to fill completely: http://www.troublefreepool.com/threads/51547-Solar-Plumbing-Layout-s?p=436641&viewfull=1#post436641

 

[big_g]

Haha, no no, not offended at all! I appreciate your help!

I'm going to run the input pipe over and around all the panels and connect it to the lower right corner. Then I'll connect the upper left to the outgoing pipe.
I don't have a vacuum release valve. Do I need one? (And where would I put it?)

 

[jblizzle]

I would recommend adding a VRV it allow air into the system when you turn off the pump so that the panels can drain without pulling a vacuum which can cause the panels to collapse in our hot climate.

You can see in the link that I provided that I put mine right where the water enters the panels, I also added a hose spigot there that I leave open in the winter to help everything drain. In reality it can go anywhere, but the higher it is the more pressure required from the pump to keep it closed. At the inlet is a good compromise between lower pressure required and keeping it high in the system.