Solar panel install

[Teald024]

Solar panel install

Aqua Leader Elegance AGP 15'x30'x 54", 12k gallons, vinyl liner ... Hayward/SwimPro Voyager pump SW159412STL, 2hp, 2spd, Hayward/Voyager 175sf element filter SW175MDDVPAKS, Installed August 2016 ... Liquid Chlorine, Stenner, Woods 50015 timer

In the begining of the year, my wife found a good deal on some solar panels on Amazon and bought them on a whim. They are Smartpool, Sunheater s220 2'x20' each for above ground pools. She got 2 of them. The actual panel model number is SCPNL220 and looks to be a standard panel from Smartpool that they package for different applications.
Sunheater SCPNL220 performance data


This particular setup for the s220 is a down & back with inlet & outlet connections on the same end.

There is a plug in the middle of the header to force the water into the proper direction. It is where the "Label" is on the right header. Unfortunatly I didn't want this setup as it is less efficient and in theory would only allow half flow through the panel.
I looked over the panel and it looked like I could pop out the plug (which is actually more like an orfice). I stuck a broom handle down the header and was able to pop out the plug fairly easily. It actually looks like those plug covers you can get, but with a hole in it.

Since I was able to knock the plug out, I redesigned the system to have both panels run in full parallel.

I actuallty laid out the panels like this

I wanted to layout the panels to get an idea how they would look. Hanging vertical, hanging at an angle. Then the same but doubled up. I originally wanted to go double wide and single length, but decided to go with the single width and double long. It made the rack too wide especially when I angled them. With the double wide, it came about 2 feet from the ground and would have been a hazard and possible damage with the kids and dogs. The single wide had it's own chalenges, but liked that solution better.

I started building the rack for the panels. I made it out of 1x6 pressure treated wood. It's not decking boards, but lumber I was able to get at Menards. I have them hanging from hinges on each fence post. The rack itself is about 30" x 40'. The rack is quite heavy, heavier than I was expecting.

I hung the panels on the rack and secured them. I didn't like that the screwhead would rub up against the panels so I had to modify the bracket slightly. The panels hand from the bracket on a slot in the panel. Then this webbing holds the pabel against the rack. I was considering changing how it was attached but I haven't yet. We'll see hown well this holds up.

Piping from the panels to the right side hinge point was next. This would give me a location to shoot for when I got to the pump pad.

On to the pad & piping. Here is the pump pad before I started.

I laid out the fittings to make sure I had the parts I needed. I effectivly replaced everything from downstream of the chlorinator to the union just left of the block valve

Oh, that first cut. I was a bit nervous taking a perfectly good setup and taking it out of commission. Here is how it ended up. I'm not 100% happy about the amount of piping hanging off the left side of the filter and return to the ground. But this is how the plumbing worked out and looks like a good arrangement. I did use compression couplers near the hinge point so that it will allow for twisting when I raise the panels at an angle.

Some notes:
I need to make a support to hold up the left side. I haven't decided if I'm going to hang it from the fence or support it from below.
I do need to go back and put a valve in the return line so I can isolate the solar totally instead of just being able to control the flow.
I still need to fabricate the brackets to hold the panels at an angle.
I didn't put a check valve in the system. We'll see how it goes without it.
I also didn't put a vacuum release valve in the system. The pool water level is actually above the bottom of the panels. The highest point in the solar lines are less than 2 feet above pool level. I feel confident that there is minimal risk in damaging the panels with this small negative pressure when shut down the system. I may end up putting it in since I did have an issue with air not purging properly on the left panel. Or maybe I'll install a Schrader valve in the cap to let me purge the air.

While I was doing the work, I did find some algae for the first time in about a year. I didn't feel a SLAM was necessary, just rinse & pray. lol...

 

[Dirk]

Is that a tab feeder? It should do its thing after the panels, not before. Actually, it should be on Craig's List, but that is a discussion for another thread!

You could use a second valve for isolation. My setup uses a check valve on the return instead. Which is the way to go if/when you add automation. You can (should) add an actuator and a solar controller to maximize efficiency, once you get tired of timing a visit to the manual valve twice a day. A controller does that for you, and many times a day when the air temp is right at the threshold of efficiency. If you have two valves, that'll be problematic for automation.

There are solar-specific three-way valves that allow the panels to drain when the pump shuts off, which is what you want for two reasons: to protect them from freezing on a cold night, and to allow them to fill each day with pool water, rather than pumping night-cooled water into your pool each day. Solar panels work in reverse at night, no point in starting your heating cycle each day with a blast of cool water. Which means you don't really want that return to go up and back down like you have there. The panels should be able to drain, not trap water.

There is also the issue of trapping air, which your system might do the way you have them mounted. The panels should be skewed slightly, not perfectly parallel to the ground. And the supply line should be skewed the other way, to allow it to drain. I think the return plumbing you have could also be a problem. This web page conveys what I'm describing, even though the panels are vertical. Give it a read and watch the animation:

http://www.h2otsun.com/PG5ht.html

Sorry, not what you wanted to hear. But it's pretty easy to build a solar system that is less efficient than it could be, because of some solar system plumbing principles that are not obvious to us DIYers...

 

[kimkats]

Awesome write up! I am going to share this thread with someone who is looking into solar!

Kim

 

[Teald024]

Dirk, you have made some good points and things to consider / incorporate into general solar builds. Some things like the slopes runs are built in as best as was possible. Vertical panels aren’t an option in this case.

I have a Stenner chlorine pump for daily dosing, so the tab feeder is only there for emergencies. I agree the best place to put the feeder is downstream of all other equipment. The chlorine injection point is downstream of the panels.
Solar automation may be in my future, but not in the budget at this time.

I agree on the benefits of draining the panels. Since I typically run the pump LS almost 24/7, it’s just another step to stop the pump to let them drain, then restart it. Running the pump that way is a compromise I’ve made to the wife’s wishes. It’s not a worthwhile debate to have with her. The bottom of the panels are below the waterline anyway so it would be difficult to gravity drain without dumping water on the ground.

The slug of colder water at panel startup, while reducing efficiency a smidge, really doesn’t have a measurable effect on temp. It really is only 10-15 degrees colder than bulk water temp. Just as adding 10 gallons of boiling doesn’t measurably raise the temp.

If I don’t drain, the risk of trapping air is minimized. When I do want to drain, there is a threaded cap on the bottom of 2 of the headers. I can remove these to drain when freezing is a risk. I agree that a couple more valves are needed and that is still on the to-do list.

The return loop is needed because in the final layout, the panels will be angled to better face the sun. I may end up putting a tee/valve/plug on the right end of the feed line near the cap in order to be able to fully drain.

 

[G.K.W.H.inthatorder]

Suuuuweeeeet!!
how cool is that!! The rack is probably how a contracted installer would’ve put them up considering liability and such like you said. 1 thought, and definitely not the perfect solution but...if you doubled them up you could potentially increase there efficiency, they’d use each other to increase they’re thermal “return”. Problem is like you said, that means they’d hang out too far. You’d have to enclose them AND worry about their heat damaging your liner as well. I’m in the beginning stages of the same type of project-yours gives me some ideas!!��
Awesome setup! The things we do for the poolwater.

 

[pooldv]

Nice work! Warm pools are great!

 

[Teald024]

GKWH, When you are choosing the layout and equipment, you want the water move fast enough to only heat a very little. Having very hot water at low flow is less efficient overall since some of that heat is lost to the environment. What counts is the BTU's that you add, not the water outlet temp.

 

[Dirk]

Dirk, you have made some good points and things to consider / incorporate into general solar builds. Some things like the slopes runs are built in as best as was possible. Vertical panels aren’t an option in this case.

I have a Stenner chlorine pump for daily dosing, so the tab feeder is only there for emergencies. I agree the best place to put the feeder is downstream of all other equipment. The chlorine injection point is downstream of the panels.
Solar automation may be in my future, but not in the budget at this time.

I agree on the benefits of draining the panels. Since I typically run the pump LS almost 24/7, it’s just another step to stop the pump to let them drain, then restart it. Running the pump that way is a compromise I’ve made to the wife’s wishes. It’s not a worthwhile debate to have with her. The bottom of the panels are below the waterline anyway so it would be difficult to gravity drain without dumping water on the ground.

The slug of colder water at panel startup, while reducing efficiency a smidge, really doesn’t have a measurable effect on temp. It really is only 10-15 degrees colder than bulk water temp. Just as adding 10 gallons of boiling doesn’t measurably raise the temp.

If I don’t drain, the risk of trapping air is minimized. When I do want to drain, there is a threaded cap on the bottom of 2 of the headers. I can remove these to drain when freezing is a risk. I agree that a couple more valves are needed and that is still on the to-do list.

The return loop is needed because in the final layout, the panels will be angled to better face the sun. I may end up putting a tee/valve/plug on the right end of the feed line near the cap in order to be able to fully drain.

I see the injector now. If you only run tabs while away, presumably you'll leave the panels bypassed, then that'll work. But I think you'll need to clean out the feeder after each use.

I missed that the panels are partially below water level. Yes, that inhibits draining unless they're fully bypassed. I'm wondering if you have the panels bypassed, if the expansion and contraction are going to be an issue.

I see now why you routed the return like that, with the unions, so the whole thing can pivot.

Regarding the air trapping and skewing the panels: it's not just about the air getting trapped, but also about the flow pattern. Water will seek the path of least resistance, so a properly tuned solar system accommodates for that. If the water flows through the tubes better in one area of the array than another, then you're getting robbed a bit. You'll get warm water out of your system even if its not setup for max efficiency, but you won't know what you're not getting. And those efficiencies I mention are slight, and cumulative. It's true dumping a couple panels full of cooler water won't affect temp to a great degree, just as tweaking the water path won't make a huge difference, just as a controller vs manual valves (if you're diligent), won't make a huge difference, just as the flow rate will only make a slight difference. But pool solar installation is about squeezing everything you can out of what you got. The difference between warm and a bit warmer.

Either way... enjoy the extra heat. My system doesn't add as much heat as I'd like all the time, but it does make for a more comfortable pool, for sure. Have a great summer!

 

[G.K.W.H.inthatorder]

GKWH, When you are choosing the layout and equipment, you want the water move fast enough to only heat a very little. Having very hot water at low flow is less efficient overall since some of that heat is lost to the environment. What counts is the BTU's that you add, not the water outlet temp.

I didn’t consider that thought. I guess I figured the loss/inefficiency would be so small since the system would not operate all year, even then, only during the day. I was thinking maaaybe...4 months, 5 tops (even that’s pushing it) —> If this then my thoughts were leaning towards “turbo boost”; I’d try to squeeze every Joule I could out of her over the limited run time. Also thought about making the system semi-disposable. Not to mention the later in the year we get the more Work she’ll be expected to produce. I’m not expecting much from this “heat engine” since constraints will overwhelmingly dictate my criteria...materials quality will be a big barricade for me. What do you think?