Pool Solar

[jerryk1234]

So they're putting in a 400K BTU gas heater on our new 60x12 lap pool. I have a feeling that the heating bill could be immense, even with the autocover. So I had them stub in for a solar installation up the hill. They trenched and installed two PVC water pipes, and one PVC electrical conduit.

My poorly considered plan was to just lay some water heating panels up
there. The hill faces southwest and has full sun exposure. Just for fun, I called a local solar contractor. They gave me a bid of 12K for Fafco panels on ground-mount racks.

**** 12K! ****

Ouch.

Surely this is something I could DIY.

I've been cruising the web - it's a bit of a rabbit hole. Seems like every solar heater panel out there is ****. People say - yes, they work, but they develop leaks. In a few years, they develop enough leaks so you can't fix them, and you have to buy another one. But maybe in
the meantime, they save you enough $$ in natural gas so it's worth it. I could put together a complete system for maybe $1.5K - including
panels, a small pump, a Hayward solar controller, bypass valve etc.

There are "economy" Fafco panels you can buy for DIY. About twice the price of the no-name Chinese stuff. But they seem to be **** also...

One continuing theme is that the panels can't take the full pressure of a real pool pump. So I would get a small low-pressure pump and dedicate it to that. The water has to go uphill about 15 feet. That's 15 feet of rise from the equipment shed; the horizontal run is longer.

Comments?

 

[sktn77a]

My in-laws in Sacramento have 6 passive panels on their single level roof and haven't had any significant problems/leaks. They's had a couple of minor leaks over 25 years but nothing that would put me off installing one. It's a 30,000 gal pool with a 2hp pump.

I realize that the climate in Hayward is cooler than Sacto but you may find that you're only heating with gas at the beginning and end of the season and the middle is self-sufficient (particularly if you have a bubble wrap solar blanket).

 

[Dirk]

Yah, my solar estimate was in the 5-figures (though that included a new pump). I installed it myself for about $3K. You can do so, too, and for even less, but I used very high-quality panels: Heliocol. They have a unique mounting system, and a unique connection system, which uses o-rings, encased in PVC, and not the typical "radiator hose" connections that are exposed to sun and are very prone to leaking. You get what you pay for.

If you want to go cheap: expect to repair and replace as needed. Or spend some money and get 12- to 20-year warranty panels and enjoy a warmer pool without hassle.

My Heliocol's are optimized for max heat output at 40 gpm (gallons per minute), and the more panels you add, the more flow is required. Which translates to about 2200RPM on my 3HP pump (my main filter pump), so I'm not sure where you heard solar panels need a "low-pressure" pump or can't make use of your "real pump." That's not true for a decent panel, and I can't imagine that's true for even a low cost panel, as most people run solar using their only (main) pump.

The distance you spec to your preferred location will not likely be an issue. Yes, you gotta push uphill 15', but there's 15' coming down the hill, too, so once the panels are full, gravity is not an issue, you'll only need to overcome the friction of the water in the pipe. Typical roof installations can go even higher, and farther from the pump, so I doubt you'll have any problem (unless the location is 100' away, or something like that).

Google "pool solar panel installation" and you'll get plenty of step-by-step instructions. It's how I learned how to do it. If you get stuck, I'll help you as much as I can.

I may have compromised my manufacturer's warranty by installing myself, but it's relatively simple, with virtually no moving parts, so not much can go wrong. If I have a failure, it will likely be in something I can fix myself, or it'll be in just one panel, which I can buy from my supplier for $300. A lot would have to go wrong before I'd be sorry I saved myself $6K installing myself!

 

[Dirk]

I bought my panels from a local solar installer. For some crazy reason, they sold me a "kit" that included my Heliocol panels at a crazy low price, plus every single thing I needed for installation, down to the screws, some paint, even the rags to wipe up spilled glue!! Everything! Unheard of, but I jumped on it, and it worked out great. They even provided some advice when I needed it. And the day they delivered the panels, they even helped me hoist them up on the roof! So you might ask around your area for a similar deal, or if my guys are still offering that, it might be worth a trip down here. Their shop is probably less than four hours from you...

 

[Poolzzz]

My Heliocol's are optimized for max heat output at 40 gpm (gallons per minute), and the more panels you add, the more flow is required. Which translates to about 2200RPM on my 3HP pump (my main filter pump), so I'm not sure where you heard solar panels need a "low-pressure" pump or can't make use of your "real pump." That's not true for a decent panel, and I can't imagine that's true for even a low cost panel, as most people run solar using their only (main) pump.

The Heliocoil panels are rated for around 4 gpm each panel so whether a "real pump" will damage it depends on how many panels you have. 4 gpm is fairly typical for panels this size. Certainly a regular pump would be too much for a single panel for example.

Most panels have a fairly low PSI rating. Enersol for example is 17psi max and even less operating. Some of the plastic type panels are even less. So pressure can and does cause leaks. As i recall the helicoil are unique in that they can take a lot of pressure.

Edit: I just looked up the fafco specs. Rate max intermittent pressure at 100C is 5 psi, at 27C it's 45 psi and at 21C it's 300 psi. Notice how steep the curve is around typical panel operating temps. Only 6 deg below 27 and it's almost 10x. Going up 10 deg to my panel temps of 37C and it might be 10x less or only 5 psi depending where the knee of the curve is. I couldn't find an actual curve, it's probably higher but maybe not by much.

Anyway I wouldn't think the pressure limits would cause problems in a proprely designed system. But one can see why reviews might have problems if people didn't know what they were doing.

 

[atttech-2]

I did a DIY Powerstrip system, all in around 4K for 320sq ft. I would have gone with a less expensive system if my roof shape had allowed for a decent amount of coverage with standard rectangle panels. Powerstrip allowed me to cover almost every sqft.

I think people often confuse filter pressure and panel pressure. When I turn my system on my filter goes from almost no pressure at 1100 rpm to 15psi at 2400 rpm. I have a 2 story house and I get around 4psi on the roof entering the panel manifold when priming, once water starts to fall back to the pool the pressure at the panel drops to around 2 psi filter pressure drops to around 13. According the manufacture for their system if the panel pressure is 5psi or less there is no reason it should not last 20 years or more.

 

[Poolzzz]

If people thought about pressure and were confused about filter vs panel pressure then they'd probably be keeping the filter pressure within panel specs which would be safe.

I actually think the opposite happens, people don't realize how low rated panels are, don't think about pressure issues and happily apply too much flow/pressure. That ends up being the source for a lot of leaks.

 

[Pool_Medic]

8 - 4x12 panels on my roof for ten + years, not one drop of a leak. Done properly and using the right panels, you won’t either.

by the way, if you get a solar controller, it will come with a powered 3 way valve, you adjust this valve to get the proper flow. No need to mess with current pump.

 

[Dirk]

8 - 4x12 panels on my roof for ten + years, not one drop of a leak. Done properly and using the right panels, you won’t either.

by the way, if you get a solar controller, it will come with a powered 3 way valve, you adjust this valve to get the proper flow. No need to mess with current pump.

Right, I was going to add that (I think) plumbing can account for all these flow and plumbing issues. Whether by using the three way, or a bypass loop, etc., to adjust PSI and/or flow for the panels. In my research, I don't recall running across discussions about PSI, only flow. I didn't want to deal with calculating or guess-timating flow, so I decided early on to invest in a FlowVis,* which allows me to dial in the perfect RPM for my panels. A VS pump was always part of the upgrade equation, that, and the ET automation, so while I had more equipment to deal with, I had less to worry about, because between the VS and the FlowVis and the ET, getting everything dialed in was the easiest part of the project.

I do believe there are ways to accomplish a properly optimized solar system without all the gear, but I can't advise much about that, because I didn't research that since I didn't have to...

*I had originally planned that the FlowVis would be a one-time use, to adjust the flow for my panels, so would be a one-time, throw-away expense. I figured once I had the appropriate VS pump RPM, that would be it for the FlowVis. I rationalized the expense based on what I thought it would take to learn and perform all the calc's necessary otherwise. Since then I've used the FlowVis often, for additional things (optimizing and re-checking flow for the panels, my cleaner system, my SWG, etc), so it's turned out to be a welcome addition to my pad and a good overall investment, which I continue to use often.

 

[jerryk1234]

I bought my panels from a local solar installer. For some crazy reason, they sold me a "kit" that included my Heliocol panels at a crazy low price, plus every single thing I needed for installation, down to the screws, some paint, even the rags to wipe up spilled glue!! Everything!

Contact info for the installer? I'm guessing that they supplied the complete kit so they could reasonably say that they were the "installing contractor".
Heliocol does seem to be a cut above pretty much everything else out there.

My plan was to lay the panels out on the hill above the swimming pool. Heliocol advises strenuously against ground mounting unless you do racks. I'm not sure exactly why. I can see problems if you lay it on the ground under an above ground pool, because then the water won't drain out of the panels,
and in the winter.... But I propose an uphill location, so no problem with drainage. I would have to cover the area with something so weeds wouldn't grow through the panels. I was thinking black landscaping plastic. Alternatively, I could contract for a thin concrete pad.

 

[Dirk]

The Heliocol panels are hundreds of little tubes fused at each end into top and bottom 1.5" PVC manifolds. About every foot or so the tubes are held in place with a horizontal member that snaps on under the tubes. It holds all the tubes in parallel, and it acts like a spacer on which the tubes lay, so they don't actually touch the roof surface. I don't know if these guides are needed for air circulation or what, but one of their purposes is to keep the tubes from scraping across the roof surface (which in my case is highly abrasive concrete tile), which would eventually wear them out. The manifolds are held to the roof with these unique mounting brackets that allow the entire array to expand and contract both in height and width. This heat expansion is what would cause the panels to move across the roof surface, and since the manifolds are not really held in place, so they are free to move, without the roof underneath supporting everything, the tubes would sag, pull on the stress point (where they are fused into the manifolds), made worse by expansion, and probably eventually start tearing themselves apart.

Point was, I expect Heliocol had problems of DIYers installing on ground mounts that didn't properly support both the mounting brackets and all the tubing in between the manifolds. I think if you basically built a roof on the ground, complete with rafters and underlayment and even composite roofing material, Heliocol couldn't complain about that. And it would last a good long time as long as you used decent roofing materials. If you're going with some sort of metal frame, you'll need to provide support for the manifolds and all the tube guides.

Contact info PM'd...

 

[domct203]

I have Fafco Sungrabber panels on a ground rack. I put them away for the winter, stored in the house.

I'm into my third season with zero issues.

As mentioned, you can control flow with the position of the 3-way valve, and/or a bypass loop. A solar controller is a must, as well as a solar blanket, or some type of cover, to reduce overnight heat loss.

 

[santacruzpool]

As an alternative I looked seriously into installing a locally made system using essentially UV stable irrigation tubing (gasp).

The company just happens to be in Willow Glen area of San Jose - Gull Industries - they make big coils with a special hub system that holds it all together so it should be a bit nicer than the DIY systems you see all over the internet...

I am sure they aren't as nice as the Helicol and Fafco panels - but they might be something for you to look at.

I had a installer quote a system and he wanted $4K - but with your system it might be a bit easier to DIY. There are several photos on their site with ground mounted coils - looks like they put it over gravel and rock in some of the photos.

I have a tall second story flat roof and it was a bit involved getting the pipes to the right location. So far I haven't pulled the trigger - our pool with a cover is sitting at 86° right now over here in Santa Cruz, so solar isn't on my need list at the moment.

 

[jerryk1234]

I have Fafco Sungrabber panels on a ground rack. I put them away for the winter, stored in the house.

I'm into my third season with zero issues.

As mentioned, you can control flow with the position of the 3-way valve, and/or a bypass loop. A solar controller is a must, as well as a solar blanket, or some type of cover

*** We will have a motorized autocover. That's $14K of the pool cost.

 

[jerryk1234]

As an alternative I looked seriously into installing a locally made system using essentially UV stable irrigation tubing (gasp).

The company just happens to be in Willow Glen area of San Jose - Gull Industries - they make big coils

** Yes, indeed! I had forgotten about Gull. Somebody gave me a quote with their coils way back early in the pool planning phase.
I think I'll call them on Monday.

 

[Rossterman]

In the west used solar panels are pretty cheap as lots of electical solar is being installed due to high electricity cost out here. Bought my last set that way 6ea 4 x 12 fafcos for $400.

- - - Updated - - -

In the west used solar panels are pretty cheap as lots of electical solar is being installed due to high electricity cost out here. Bought my last set that way 6ea 4 x 12 fafcos for $400. Check craigslist perodically. Be sure to check panel mfg dates before buying though. Some I looked at were end of life and brittle. Eventually I found some 3 years old that looked brand new.