Question about solar panels

[farmgirl]

Ok. Here is the situation. We have a 24 foot above ground pool with four 2x20 foot solar panels for heat. The panels are set up side by side, (joined together on the short ends) with inlet on one end of the hose linking all four panels at one end, and outlet on opposite end.

(from pool)----panel1----panel2----panel3----panel4-----(to pool return)


Sorry about the rough "sketch"...but i hope it gives some idea of the setup we have. Now, the problem is this. The pool is heating, and it seems that the two OUTER panels (#1 & #4) are working OK....they feel almost COLD to the touch, even in very hot sun. The 2 center panels (#2 & #3) always feel hot, and are not as heavy as the out panels, indicating to me that there is little if any water running thru them. DH says that the way he has it set up, if ONE panel is getting water flow, then they ALL HAVE to be getting water flow. I say that makes sense, but why are the panels not all the same weight and temperature? Our pump is a 1.5 HP 2 speed pump, but stays on "low" when the solar is running. Any input will be appreciated, as we have been arguing about this for over a year!:eek:

[matt4x4]

OK, confused - pic shows a series setup, yet explanation sounds somewhat like a parallel setup.
Need to know which way it is.
What you describe with the heatup of the panels (and it sounds like you also have a mix of different panels) makes it seem like a parallel setup where water will take the path of least resistance (the cool panels) and the other panels stay stagnant and heat up.

The way you have to set it up is as follows:
water from skimmer to pump, from pump to filter, from filter to INPUT on SP1, from OUTPUT on SP1 to INPUT on SP2, From OUTPUT on SP2 to INPUT on SP3, from OUTPUT on SP3 to INPUT on SP4, from OUTPUT on SP4 to return jet.
This is the ONLY way you will get water moving ewenly through all panels.
If you run in parallel, there is no guarantee you will get the water moving through all panels.

[JohnT]

If the middle panels are hot, they aren't working. Here's a link to an image that shows how they should be plumbed.
http://www.sunpowersolutions.com/images/SolarPool/SolarSystem.jpg

[farmgirl]

I guess you would call it a parallell setup. The pic i did is not too descriptive. Let's see if i can put it into words. All solar panels laid out with long sides facing long sides. All connected at one end where water flows from pool to panels and back to pool.
============P <<<<<<<<Pool skimmer, etc
============P
============P
============P >>>>>>> Pool return

Hope this helps. DH STILL does not believe there is anything wrong with them! ARGH!

[NWMNMom]

Where/how are the individual panels connected to each other? And what brand are they? Some are molded/manufactured so that EACH panel will have a "loop" in them that forces the water from the INLET on the bottom of a labeled end (usually bottom right if label is facing up) across the bottom to the left, up and back acrossed the top to the right at an OUTLET on the top right of the labeled end - a connector hose runs from that OUTLET to the next panel's INLET and it repeats its path through each panel that way.

Then if that brand is manufactured/molded in that manner, would the panel not be able to be plumbed without some kind of modification to just run in all across one end and out all across the other end as shown in the diagram above? I know we just kind of went through this in an earlier post, with this attached diagram showing what was suggested there - the idea being that all panels receive the incoming cold water at the same time and all panels send their heated water to a shared outlet at the same time (probably with some better variation than shown here to equalize the pressure across all inlets and outlets). Dimensions for demonstration only, not meant to be exact or anything. Layout could probably be modified to better fit an area, so long as the plumbing path and end result are the same.

Ok guys, IS this what was suggested before for a more efficient use of multiple panels of this type (with internal loop)?

[farmgirl]

That is EXACTLY the setup we have, except there is only ONE hose connecting everything together. There is ONE line plumbed from filter, to panel one, panel two, panel three, and panel four, back to pool return. All 4 panels are plumbed at one end, and capped off at the other end. Maybe this makes more sense than my previous descriptions. Wish i knew how to post a photo! That would make it much simpler!!! :p

[matt4x4]

Farmgirl - go read my post above, I guarantee you that is your problem, to fix it, take the HOT panels, flip them on their long end (like a Mattress - place the head to the feet).
Move the caps to the opposite end and reconnect - problem fixed.....

[matt4x4]

Here's the pic I drew up to help explain....
I'm having real issues trying to EDIT a post - this happened last night too (I just noticed) so don't go looking above since my edit didn't take and I'm not telling you anything new up there!
NOW, I'm going to tyell you what I tried to post last night!
The panels you have are like what I drew, TWO of the black rectangles in my dwg are ONE panel, so my drawing contains two panels total.

Water comes in the input, fills the big input/output pipe to the half way mark (Because it is physically blocked half way), water then starts to travel down HALF the WIDTH of the panel to the far end, the pipe at that end is NOT blocked and directs the water to the OTHER HALF of the panel and back to the OUTPUT half of that blocked pipe. (essentially makes the water travel in a U
If you end to end reverse a panel, you will just pump water in and right back out the big pipe since it does NOT have a PHYSICAL block in the pipe - the water never even makes it into the panel.
Flip your warm panels end to end, move the caps to the opposite end and reconnect in line where you just removed the caps.
An easy test is to remove one cap from the far end, stick a wooden dowel or some type of stick into the tube as far as you can, mark it and see how far in it went, if it went in half way your panel needs flipping end to end., if it went all the way in your panel is installed correctly.

[farmgirl]

Ok Matt: What you say makes sense...BUT....All 4 of my panels have stickers on them that tell which end is supposed to go where, and which sides are "inlet" and "outlet". We have them set up as per manufacturer's directions, so we are a bit confused. This is a REAL SORE subject between DH and me, but he says he will try and help me figure it out over the weekend. I will have him read your posts tonight, and perhaps he will try a different setup with the soalr. Thank you so much for the tips! At this point, i will try anything!

[farmgirl]

AHA! I went home on lunch hour to see if the panels would do anything different with a few adjustments. I read earlier that if your flow from your pump was too strong, you may get incomplete flow thru the panels. So, I diverted the water flow by half, and guess what........with the water diverted, and the pump on the HI setting, ALL the panels turned cool (ie, they were working!) Weird, but i still do not understand why the 2 center panels do not work if the pump is on low. Any ideas? I did not think this was so complicated!!! :o

[matt4x4]

Question:
Are you feeding the panels on the lowest point or the highest point?
It's probably best to feed at the lowest so any air pockets can get pushed out.
I would still take one endcap on each of the suspect panels off and see if you can push a stick/rod through to the other end cap - who knows, maybe the labels are applied wrong - unscrewing the caps is not much work so it may be worth a try.
Another thing is that trapped air may then escape and alleviate this issue in the future.