Solar Panel Heater Questions

[CarlD]

Hey folks,

I'm considering purchasing some Solar Panels to heat my pool. Got a bunch of simple questions for you guys:

1) I'd prefer not installing it on my roof just yet. Can I install these vertically (straight up and down) against my fence, or does it need to be tilted diagonally?

The issue is support. I'm a big fan of just laying the rollable panels on the ground. If you aim them well, you get as much sun as any other way. Plus, the ground absorbs heat and can extend your run time on the panels--be sure to be able to turn them off even if the pump is running.

2) Can this be left out in the winter time?

If you live in the Caribbean, sure. But if there's ANY chance of freezing, no. The rollable panels should be drained, rolled up and stored. Quick-release fittings near the panel connections make this more painless.

3) I would be installing it myself, however I am hearing that there is a lot of considerations relating to water pressure and something related to the pump head. Is it easy to figure all this out?

Since you are doing a simple A/G pool setup a lot of that can probably be gotten around without too much figuring. If you just Tee off your return, and put a valve there, you can control the flow to the panels, as long as the distances aren't too big. Generally, you can compensate by adjusting the valve. I know, I know, this is heresy, but I've done it 3 times on 3 different pools successfully. When you go to the roof, then you'll need to do the figuring properly.

4) I have an 18X36 foot pool (I believe). All I can really fit as far as the panels go would be 4X20 or 6X20 worth of panels. I know this is not ideal, but will it make enough of a difference to justify doing this?

More heresy from CarlD! The recommended amount of panels is IMHO, the MAXIMUM you should use. It can be amazing how much panels with 20-25% of the pool's surface area can accomplish...and if you place the panels to get something extreme like 12 hours of sun a day, you'll be delighted with the results. I keep citing the example of my parents' pool: I had 22% of the S/A, and only 6 hours of direct sun a day, yet the pool consistently was 6 degrees warmer than it ever had been. According to the experts it should have been ineffective, but my folks were delighted--the pool went from 78 to 84--a big difference.

Furthermore, if you plan for adding more panels in your plumbing scheme and just cap off fittings, you can always add them later. Aim for a parallel system rather than in series.

So you start with what you have, and see if you are satisfied with it. If so, end of story.


5) Until I do install this on my roof (a few years from now) I would have the PVC piping above ground. No issues with that, right?

You have an AG pool, right? You have PVC all over anyway. All it is, is ugly. I like to have lots of quick connects so it all pops off in minutes at the end of the season. Since I mostly have flexible PVC, it rolls up.

6) My estimate for pulling this off is in the neighborhood of $1,000 (give or take a few hundred). Would you agree?

On the ground? Easily. I did the system for my parents for $500--with a 4x20, a 4x10 and a 4-way valve to control the return on Dad's filter.

7) Is this truly as easy as it sounds to install this?

Be sure to use glue-on fittings to attach to flexible PVC. Internal fittings and hose clamps will leak. Other than that, with a little planning it's not too hard. If you want things to screw in, use glue-on tapped fittings. Only use Schedule 40 rated fittings, or higher (like Schedule 80). Non-sched 40 fittings are not for pressurized systems--they are for drains. Gluing PVC is a piece of cake.

Thanks a lot!

[NullQwerty]

Thanks CarlD!

This is actually an In-Ground vinyl pool. About 18X36 so I estimate about 24,000 gallons.

I'm all good on attaching the PVC fittings. That's definitly the easy part and have done that a few times. I am hesitant though on the whole water pressure part just because when I do it, I am concerned that I won't be aware if I don't have things adjusted properly. What should I be looking for exactly? Just nice flow on the return lines?


Thanks!

[mas985]

A few comments on panel size:

As Carl points out, if you only need a few degrees heat rise, then you probably don't need many panels.

However, the more panels you get, the faster the pool will heat and the higher the temp difference.

One advantage of a large solar panel is that it can extend your swim season if that is something you are looking for.

This is why I went with 85% area coverage. This year it really paid off. We had a few warm days in March and I was able to bring the water temp up very quickly to the high 80's. With a solar cover, I have been able to maintain 85-90 since then so when the air temp is warm we can swim right away instead of having to wait several days for the water to warm up.

I can get over 15 degrees of heat gain with my panels and I have easily extended our swim season a couple of months on each end. This is useful for where I live but may not be so important where you are.

So it really is all about what you are looking for in performance.

As for pump head, most in-ground pool pumps can easily handle solar panels even if they are on the roof. On the roof, the pump will temporarily experience static head which is the water lift to the top of the panels during the priming phase. So if the upper most part of the panel is 25 ft high, that is 25 ft of static head. After the panels are primed, the water falling on the other side cancels this out so you are left with only the dynamic head increase which is usually much less than 8 PSI (20 ft of head increase).

A decent rule of thumb is that the pump should be handle twice the height of the panel so the priming is fast and the vacuum release valve is closed quickly. For a 25 ft. high panel, at most only 50 ft of maximum head is need. Nearly all inground pumps provide this.

[CarlD]

Well, I have about 2/5 coverage ( 640sq ft pool, 240 sq ft panels==> 37.5%) and today, the Saturday of Memorial Day weekend, here in Northern New Jersey, my pool is 90 degrees! I can get 8-10 degrees of increase when I use them full blast.

That's despite having a nasty, rainy month of May. When we have a nice sunny 2nd half of April we'll be in the mid 80's by early May and swimming. We can only extend our swim season when the weather cooperates, but my opinion is that when the weather stinks, who wants to swim anyway?

As I said, I preach heresy on this!

[Watermom]

On my 24ft AG, I only have one 4x20 panel and it makes a big difference.

[NullQwerty]

Thanks so much everyone!!!