Started on Solar Heat Project

[WardL]

I'm planning to install solar heat to my pool now. I have the piping in the ground to the side hill area I plan to ground mount the 700 SF of panels. I got an estimate of $14,000 which I think is pretty good, but I want to save some money and do it myself. I was looking at the Vortex or the Techno-Solis panels. I think they are the same panels sold under different names. I want the 2" headers. Any suggestions for panels I can purchase without a contractor would be appreciated.

One issue I want help with is the operating pressure effect on life of the panels. Since it is a ground mount system, it will be about 15' below the pool at the bottom of the panels. This will produce a static pressure of about 7 psi. There is a 10-year warranty, but I don't want to mess with a warranty. I want the panels to work without leaks. Does anyone have experience with these brand panels on a ground mount system?

I was going to build the rack with aluminum and cement it into the ground. I've done searches looking for tips and ideas but many of the posts are old so I thought it would be worth an update. I live in a very moderate climate and don't expect any freezing. Thanks for any comments ahead of time.

 

[pooldv]

Yes, Vortex and Techno-Solis are the same panels. I bought my Vortex panels with 2" (edit: they are 1-1/2", not 2")) headers from solardirect.com and installed them myself. I don't know for sure but I can't imagine that 7psi will do anything to shorten the panel life.

Isaac-1 has techno-solis panels that he bought and installed but I don't know where he bought them.

 

[WardL]

Thank you for the info. Could you describe your experience with the Vortex panels? They seem to be pushing the 1.5" headers, but I'm going with 2". Did a contractor install your panels? Do you have any suggestions or traps to watch out for? I'm guessing you have it mounted on your roof?

 

[pooldv]

There are pics of my panels and pool equipment in the link in my sig. I did the install, it was very simple. I said above that mine were 2" but now I'm thinking they might be 1-1/2". It is cold and raining so I'm not going to go check right now. looking out the window it is plumbed with 2" pvc and the headers are obviously 1-1/2". Whatever it is works great. They've been installed for at least 3 years now. No issues and they have put a lot of heat in my pool. Giving us many extra swim days every year. I would install more panels if I could but I'm out of space.

 

[WardL]

I have finished mapping out the hillside for my ground mount panels. I was planning two 350 SF sections. They would not be lined up side by side, but at different elevations. One section of panels will be about 8' higher than the other section. For balanced flow to each section, it seems necessary to have the two bottom cold water supply headers at some point to be at the same elevation. Does that make sense? Appreciate any thoughts on how to position the two sections on the hillside so they have even flow to each section of panels. I could add valves to direct the flow, but would prefer not to do that.

Again, thanks for the info. Nice looking solar set up and pool!

 

[pooldv]

Thanks! I bought my panels from Solar Direct, they have quite a bit of info here, Vortex Solar Pool Heaters, solar heating your swimming pool

They cover double row installation here, http://shop.solardirect.com/pdf/pool-heaters/solar-pool-heaters/collectors/vortex/vortex-install-manual.pdf

 

[Isaac-1]

Sorry about being late to the party, have not had much time to spend on here the last couple of months. I bought my Techno-Solis panels with 2 inch headers from Pool Heat Pumps, Pool Heating Systems, Pool Heaters

As to installing at below pool level on a hill, you may want to read Hot Sun Industries Case Study Rigid Solar Pool Heating Panel Issues with Pressure and Variable Speed Pumps

p.s. note that HotSun does tend to slant statements in favor of their design, this does not make the underlying concern less valid.

 

[xyz]

Depending on your configuration, you may be able to connect the panels serially. This won't be quite as efficient. Also, the "make your own size" arrays from HotSun may provide you with an alternative that doesn't require as much plumbing or complexity. Also, the HotSun PVC will be more resilient to the higher pressure, and may provide you with the flexibility to make your install easier. It may be more expensive, but I would think a 700 sqft array, if it were simple would be 7-8k or so, if you are doing a self install.

What are you installing the arrays on?

 

[mas985]

As to installing at below pool level on a hill, you may want to read Hot Sun Industries Case Study Rigid Solar Pool Heating Panel Issues with Pressure and Variable Speed Pumps

p.s. note that HotSun does tend to slant statements in favor of their design, this does not make the underlying concern less valid.

They also leave out some critical information. For example:

The specification for a Fafco Sunsaver solar panel is a maximum intermittent pressure of 5 psi at 212F. Solar panels can get that hot although more typical high temperatures are more like 185F.

This can only happen when the panels are off for a while and then turned on while at that high temperature. When the panels are on, they never reach temperatures much more than a few degrees above the pool water and the pressure specifications are much higher at lower temperatures (e.g. 30 PSI at 80F). So you can avoid this situation by running the panels when the sun first hits them and if they shut off later in the day, have the pump shut off at the same time (e.g. using solar extend) and leave it off.

But really the biggest issue is that they are trying to run solar at the same time they are running the in-floor cleaners which require higher pressure. With a VS or even a two speed pump, you can run the panels at very low pressure without any issues. But you are right that you have 7 PSI of static head to deal with so not much margin:

Techno-Solis specs are +- 10 PSI, 35 PSI short term peak: Specs

Since you have a variable speed pump, you should be able to keep the panels below 10 PSI but that may affect your infinity edge because of the low flow rate. One option is to plumb in a separate return for the solar so you can bypass water around solar to keep the pressure down in the panels while still having higher flow rates for the edge.

However, 700 sq-ft is a really large area for a 15k pool so the panels will need to be shut off at times and possibly during the heat of the day. This is where you can have problems because the panels will not be self draining so the water will continue to heat up until it does reach high enough temperatures to cause issues.

So given all these things, I too think you may want to look at panels that can handle higher pressure at higher temperatures just avoid any issues.

 

[xyz]

Mark brings up good points here, and saw something I didn't see. I have a 28kgal pool that is approx 500 sq ft surface area. A very general rule of thumb is 1:1 for solar. I'd guess this means your pool is likely less than 350 sq ft. (Maybe you have high wind? Maybe you want a very long season? Maybe you have a lot of masking from trees?

If not, why not go with just a single array that is the higher one? You can always add the second array if you want more, yet if the single array works well, you have saved bucks and don't have as much pressure to deal with.

I'm also imagining a system where you add a pressure regulator on the bottom of the array, and then use a small circulating pump dedicated to the solar that just pumps the water up and into the pool. When the pump turns off, the array(s) drain (vacuum breaker at the top).

 

[WardL]

I am sorry I've been away from this post for so long! I have the panels now and am making the final plans for the aluminum ground support system. I was planning on using 2" angle bar in concrete for posts and a perimeter frame of 2" angle bar with 1.5" support bars. Two parallel sections will be about 28' x 12' each. I need to do some more work to feel comfortable with the 2" angle post's strength and how many posts. I might go with 2" square bar. I didn't want to use wood because I want to do this one time and never again. I've read where sheathing is recommended underneath the panels and I'm considering plastic corrugated sections available at Home Depot as sheathing under the panels. I do live in a pretty high wind area. The panels will be on a side hill facing south. The top of the panels will be a little below the level in the pool. I was worried about the pressure in the panels and felt I had to go with panels that had a 140 PSI pressure rating. I know this is an expensive way to go, but am OK with spending the extra $ to do it right. Ha, the big question is am I really doing it right? I have 2.5" supply and return headers put in when I built the pool.

As always, your comments and questions are appreciated.