H2ot Sun Ballasted Flat Roof Solar Install

[Telemachus]

My wife has been wanting solar pool heating for more than a decade, but our roof space is severely limited with PV panels occupying most of it.

During COVID we installed a free-standing insulated alumawood patio cover to give us an outdoor entertaining area.



I then got several opinions on installing pool solar on this patio cover. I found a few companies that would do it, but they said I effectivity waved and warranty by putting the panels on a flat surface. While it doesn't freeze often in sunny SoCal, once it's enough to destroy pool solar panels that aren't drained. Without a slope to the roof, draining is difficult and involves forced air.

After some searching I got in touch with Ken Wright with H2ot Sun industries. While he is in Canada, Ecosolar out of Upland California distributes for him in the U.S.

Of particular interest to me was his ballasted flat roof system:

Solar Pool Heating on Flat Roofs- Ballasted

No roof penetrations are required to mount Powerstrip solar collectors on sensitive flat roof surfaces

www.h2otsun.com

My initial call to Ken confirmed that his system was exactly what I needed for the following reasons:
1) Ballasted system means no roof penetrations.
2) Elevated headers with flexible fin tubing means only the headers have to be drained for the winter. Water left in the flexible tubes is fine since they can expand without breaking.
3) Custom lengths means I could fill the entire surface instead of sticking to premade sizes.
4) Ken offers full support for DIY systems. He provided almost everything I needed to install the system and has a complete manual that walks through the installation step-by-step. Plus he designed the system with ballast placement and cross bars for uplift support. The heavier/longer parts of the ballasted system are purchased locally at The Home Depot.

I went with 15 1'x30' panels. The panels were premade for me.
Here are some snaps of the install from beginning to end:








My pool was at 68' two weeks ago, and now with 450 square feet of h2ot sun pool heaters I am hitting 85' every day.

Overall Ken's customer support and DIY help aids are superb! Not to mention Austin in Upland's meticulous packaging of all the items.

I am quite pleased with the outcome. If you can plumb PVC sprinklers, you can plumb a pool solar system!

 

[ajw22]

Very nice.

I think @Dirk would be interested in reading about this.

 

[Dirk]

I'll have to come back to finish the read, I just had time to scan. Sounds like it's worked out for you. That's good to hear about H2ot Sun industries. I've been pilfering the knowledge on their website for years! And sharing it with others here, and sending folks to their site. Did you use them based on hearing about them from TFP, or is that just a coincidence?

 

[Telemachus]

I'll have to come back to finish the read, I just had time to scan. Sounds like it's worked out for you. That's good to hear about H2ot Sun industries. I've been pilfering the knowledge on their website for years! And sharing it with others here, and sending folks to their site. Did you use them based on hearing about them from TFP, or is that just a coincidence?

Coincidence.

In fact, I could find almost nothing about them on here... I asked, too.

H2otsun Solar Powerstrips

Ken at Hot2Sun has been great to talk with in regards to his unique ballasted power strip solar heaters to go on a flat patio cover. Freezing is not common in Socal, but it ruined my neighbors traditional panels the first year he installed them. Plus I don't want to penetrate my patio cover...

www.troublefreepool.com

Ken has an engineering background and has been at this for decades. I see material from him quoted all over the internet, but could find almost nothing about his actual product.

Some of what he suggests is contrary to the way that many solar systems are plumbed in.

For instance, he suggested plumbing in the solar AFTER the gas heater, since he has pressure tested systems at just about every point, and has found that the gas heater drops the pressure in the systems by about 5 PSI. That way, less barotrauma on the solar panels themselves. He also suggested plumbing it in AFTER the SWG, but the (miniscule) potential for hydrogen gas formation in the solar panels and the ease of plumbing in post gas heater deterred me from doing that.

 

[Dirk]

Looks good. Interesting about the "expanding tubes" to account for the possibility of a freeze. I hope that works. The only other thing to note is about the roof surface. My panels have a system that allows them to float over the roof. It was quite a pain to get it right, but my tubes don't actually touch my roof tiles. I felt this was important because the tiles are abrasive and the entire solar array, tubes and manifolds, all move in every direction due to expansion and contraction. Both length and width.

What is your roofing material? Was there any mention in Ken's doc's about the panels abrading on the roof? Tiles would be a bigger deal, I expect, because unsuspended the tubes would be draping over the edge of the end of the tile, sawing back and forth. Perhaps on a flat surface there's less of an issue.

I really like the notion that you could order custom lengths. That's great.

Not to keen on the notion of pumping super-chlorinated, hydrogen-gas-rich water through my panels. I'll take a pass on that idea. Before or after the heater? Interesting. My gas heater is after my panels. Just the way the plumber did it. I barely understand the bit about the pressure. I'll have to take Ken's word for that. He does seem to be worried about barotrauma. But I'd be more concerned about the heat loss of running the gas-heated water up onto the roof, especially during the cooler parts of the day. That makes no sense at all. You'd be running all that expensive warm water into a giant cooling radiator! Am I missing something? I suppose you wouldn't be running solar and gas at the same time, but why couldn't you? Especially if the gas heater was after the solar. You'd get a bump from the solar, and a second bump from the gas. Eking out every therm you could, and lowering the cost of gas heating by adding the heat from the solar. I don't know, I've never tried that. I've actually never turned on my gas heater. But I've always assumed I could run both at the same time if I wanted to. Is that not a thing?

 

[Telemachus]

The plumbing can shift in the sleeves of the balasts. The tubes themselves are a soft/flexible plastic. Very unabrasive. My surface is just painted aluminum.

Here is a video for anyone interested in the actual installation:

Yes I opted against the post SWG idea.

My Pentair Easy Touch 8 doesn't give me the option to run gas and solar together. I can't imagine a scenario where I would actually do that... The plumbing was easiest in that spot so it was an easy sale.

Longevity of the panels from less pressure trumps the gas heat loss scenario.

 

[Dirk]

EasyTouch 8 here, too. The three heat options are solar only, heater, solar preferred. No heater and solar together. I guess it's not done. You could manually move the solar valve while the heater was on, I suppose. Must be some safety or system reason for Pentair to leave out that option.

There's are solar and heater buttons on the ET. I've yet to figure out what they do. I only engage the solar through scheduling with ScreenLogic. Or turning it on via ScreenLogic if I want it to come on outside of the schedule. It's academic, as I don't plan on ever turning on the gas heater. I don't even know if it works. Or what happens to it if you don't use it for 7 years!

Is that a heater bypass mixed in there? I wish I had one.

 

[Telemachus]

EasyTouch 8 here, too. The three heat options are solar only, heater, solar preferred. No heater and solar together. I guess it's not done. You could manually move the solar valve while the heater was on, I suppose. Must be some safety or system reason for Pentair to leave out that option.

There's are solar and heater buttons on the ET. I've yet to figure out what they do. I only engage the solar through scheduling with ScreenLogic. Or turning it on via ScreenLogic if I want it to come on outside of the schedule. It's academic, as I don't plan on ever turning on the gas heater. I don't even know if it works. Or what happens to it if you don't use it for 7 years!

Is that a heater bypass mixed in there? I wish I had one.

The heater and solar buttons only work in SERVICE or TIME-OUT mode.

I don't have a heater bypass. There's just an emergency solar bypass that I plan to paint bright red so the wife (and fire department) can easily find it if needed.

I thought a great deal about how I wanted the plumbing before I made my first cut. I'm pleased with how it turned out.

I have not yet plumbed in the check valve that is supposed to go right after the filter. It seems to be working without it, so I'm debating saving the $60 and returning it.

You should fire up the heater. If nothing else it will burn up all the spider webs in there.

 

[Dirk]

The heater and solar buttons only work in SERVICE or TIME-OUT mode.

Ah, of course. Thanks.

 

[Ahultin]

Can I ask where you put the vacuum breaker? I thought it went on the panels at the high side but was told today that it should go at the equipment pad on the supply side. My brain can't seem to wrap around how this will work. My panels will be ground mount, approximately 6ft below pool level so I have to put a Manual drain on the low point of the supply for use in the event of freeze (I'll also program the intellicenter for antifreeze)

 

[Telemachus]

Can I ask where you put the vacuum breaker? I thought it went on the panels at the high side but was told today that it should go at the equipment pad on the supply side. My brain can't seem to wrap around how this will work. My panels will be ground mount, approximately 6ft below pool level so I have to put a Manual drain on the low point of the supply for use in the event of freeze (I'll also program the intellicenter for antifreeze)

Mine is at the highest point on the panels, on the return side.

But I plumbed in a tee in another spot on the supply side that has a pressure Guage in it for testing.

You could just put a tee in both places and move the vacuum breaker to whichever one works best.

My guess is you want it at the highest point (by the equipment in your case) so that when the water falls down to the panels the vacuum breaker gets pulled down and releaves negative pressure.

 

[Dirk]

You stumped me with the ground mount. Mine is on the supply side, just under the eves, not up on the roof (I wanted it in the shade, and it doesn't have to be at the highest point, contrary to logic). There is a science to its placement. Where it goes can affect how low you can run your pump. My uneducated guess is that with the panels below the pool, it's not going to matter. Except for the winterizing, your panels will always hold water, and so the breaker would only kick in when you drain 'em once a year.

I always lean on @mas985 when solar plumbing stumps me...

 

[Telemachus]

There is no harm in plumbing in several potential places for it. Like Dirk said, where isn't as important as how low you can run your pump without it sucking (and constant pool bubbling). You might end up moving it and plugging the original spot.

Not that I am any expert... just my 2 cents

 

[Ahultin]

There is no harm in plumbing in several potential places for it. Like Dirk said, where isn't as important as how low you can run your pump without it sucking (and constant pool bubbling). You might end up moving it and plugging the original spot.

Not that I am any expert... just my 2 cents

Makes sense to me, ill put a tee and threaded bushing where I think it goes and another where I'm told it goes, what's another 6 bucks in the scheme of things

 

[Ahultin]

You stumped me with the ground mount. Mine is on the supply side, just under the eves, not up on the roof (I wanted it in the shade, and it doesn't have to be at the highest point, contrary to logic). There is a science to its placement. Where it goes can affect how low you can run your pump. My uneducated guess is that with the panels below the pool, it's not going to matter. Except for the winterizing, your panels will always hold water, and so the breaker would only kick in when you drain 'em once a year.

I always lean on @mas985 when solar plumbing stumps me...

We had to ground mount as our roof is mostly 12/16 pitch facing the wrong ways. The one spot they could go on the roof is over a porch on the west side of the house that's shaded 2/3 of the day.

 

[Dirk]

We had to ground mount as our roof is mostly 12/16 pitch facing the wrong ways. The one spot they could go on the roof is over a porch on the west side of the house that's shaded 2/3 of the day.

I think ground-mount is fine if you have the room. Heck, I'd cover my panels for six months of the year if they were on the ground. Might get a few more years out of 'em. I just don't know the physics as well as I do for roof-mount, so I can't be of much help.