Solar Panel Connection layout

[NWMNMom]

Ok, so the 4x20 solar panel was ordered, we come home with the box on the deck (UPS while we were at work) It contains 2 separate 2x20 panels with connectors. I was under the impression we were getting a single 4x20 panel because that is what it shows on the website, not 2 that needed connection. This means that with my existing panel, I have 3 of the 2x20 panels that need to be connected together - ARGHHHH! We HAD intended to connect them side by side (when we thought it was only 2 total panels) as Carl had instructed in another post. We were going to mount them elevated even with the pool top rail level and angled (35 degree) on a post system off the north side of our pool with a T going in and a T going out so that water is going through both at the same time.

Do I mount these as shown in the instructions AND put the T to go to the third panel side by side with it or ????? We do not have 60 feet of space to do side by side series with three panels! With the connections on the two in the box, its a bit more than 4 feet high. As someone said in an earlier post, the directions included for the panels show a parallel connection that heats the water in the first panel and then runs it to the second panel to do it all over again. I'm confused on what to do with these. If we put them on the ground on the south side, they may not get enough sun - we can't roof mount, its too far away. Any suggestions?

[rmeden]

I haven't seen any pictures on a 4x20... even when sold as a 4x20 it mentions 2x2x20.

BTW.. the panels I got from ebay were missing the internal diverter that forced water to go in a U shape in a 2x20 section. I suggest you test them on the ground first.

In the sun, the panels will get hot. When water is running through them, they will not be hot. It's easy to tell they're working (no hot spots)!

The physics says you'll get the most BTU transfer with the least delta-T(emp) (moving more water through it) .. that's why parallel is better than serial flow (you'll also have less head pressure)

Per instructions (at least for my panels)

   ||>>>>>>>>>>>>>>>>====return
   ||<<<<<<<<<<<<<<<<||
                     ||
   ||>>>>>>>>>>>>>>>>||
   ||<<<<<<<<<<<<<<<<====pump

Theoretical Best

   ||>>>>>>>>>>>>>>>>||
   ||>>>>>>>>>>>>>>>>||
   ||                ||
   ||>>>>>>>>>>>>>>>>||
   ||>>>>>>>>>>>>>>>>||
   ||                ||
   ====pump          ===return

I cabled it up like this (using parts that came with the kit.. I didn't have a second couple for the theoretical best

   ||>>>>>>>>>>>>>>>>====return
   ||>>>>>>>>>>>>>>>>||
   ||                                      
   ||<<<<<<<<<<<<<<<<||
   ||<<<<<<<<<<<<<<<<====pump

I don't recommend you knock yourself out trying to get the "best". The differences are probably negligable. Go for what's easiest to do. I adjust the flow through the panels to limit the temp rise to 10-15 degrees. Enough to make me feel the panels are working even thow the efficiency is lower than if I ran more water through it.

Robert

[tphaggerty]

I would go to powermat.com. There are some great diagrams of how these systems work and how they should be piped. The diagrams are for permanent installation, but the idea is basically the same. As rmeden said, the idea is high volume, low tempature rise. If you can put your hand on the panels when the system is running and they are hot, then you system is not running effectively.

Our panels have the input coming in at the bottom with all of the panels connected at the bottom, the last bottom tube is capped. All of the top panels are likewise connected, however the first panel is capped and the last panel feeds to return. The panels are also angle slightly with the highest point being at the return panel. This arrangement forces the water to go through all of the panels and prevents air from being trapped anywhere (bad, air doesn't conduct heat well).

[CarlD]

I would send them back and tell them to send you what you ordered, not what they wanted to sell you. Why use 2 2x20's in an application that a 4x20 will do? Lot more plumbing...

[NWMNMom]

I called this morning and he said they actually don't sell the 4x20 single and that they just use the photo from the mfg because they didn't have a photo of 2 of the 2x20s assembled. So, I guess we can make do if we have to. We have already had to send back a box that was damaged when it arrived.

Our thoughts on install - because of the limited sun (shadeless) area south of the pool area, we thought of mounting them on posts as shown in diagram attached just to the north of the pool (diagram shows distance between but will actually be about 2-3' north of pool in front of pine tree row) So, would this layout be efficient? We used a diverter on the single panel we had before for the 18' round, thought we should keep that in the loop. This setup gives us about 40 or so feet of panel area - the total space available is only 54' from east to west. I believe these all have the internal loop in the panels that force the water from the inlet at the bottom to the end then back to the front of the panel out the top. I know the single one does and it is the same brand as the new set.

Feedback? other suggestions?

[tphaggerty]

Nice diagram. I see 2 potential problems that might not really be problems but you should think about.

First, the pressure drop across the right set of panels is going to be twice what it is across the left panel. Not sure what the result might be, but "smooth flow" through a solar system makes it more efficient.

Second, the water entering the 2nd panel on the left (in series) is already heated, my guess is that the 2nd panel is not going to be as efficient. Any type of heater works best when the tempature differential is as great as possible.

Seems like it would add only a little to split your input into 3 streams to feed each panel, then join all three on the return side. I think it would balance the system a lot better and the pressure differential across all 3 panels would be the same.

[NWMNMom]

You mean make the T into a "Tree" so that all three panels get an input feed and all three go to output. This can be done, just will require a longer feed from the "Tree" to the third panel and longer output from Left bottom panel to output "Tree" - all due to layout and space limitations. White PVC schedule 40? or the gray PVC?

This setup could end up adding a 4th panel at some point if we don't get enough warm water from this, but I think with a normal summer, we should be able to do fine with the three panels.

The pool prep, planning and the maintc is my "baby" - the hubby just helps with the grunt work and relaxes in it when its ready. Thanks - getting this straight in my head by running it past others really helps.

[tphaggerty]

I think that is what I would do. But, the company you bought these from must have some plans, suggestions for multiple panels. What do they say?

[NWMNMom]

Its a pool supply, they don't really offer any help here. They suggested we roof mount, when I told them how far away and that it would have to cross a driving area, it was Hmmm, don't know. I like my post mount idea, just needed to have someone tell me I'm not crazy and to help me get efficiency tuned up. Thank you so much.