Solar panel brands better for almost flat metal roofs?

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M

markw

0
Aug 22, 2012
25
Memphis
I am looking to do a DIY install of solar heating panels for my IG pool. We have an existing wooden pergola that has a metal roof with very little pitch. I don't have the exact pitch, but think of it as a few inches or just enough to keep the water flowing off the metal roof. I know the structure itself is strong enough to hold the panels containing water, and it would be much preferred to install them there for two reasons. One, they would be almost unseen, and two, I know this is not truly an issue but it would in fact keep me from putting holes in a perfectly good, new roof.
Are certain panels or brands better for this kind of application? Thanks!
 
Thank you both for the quick replies. I'll post a sq ft number tomorrow after I take real measurements tonight. It won't be huge coverage but should border on 50% of my pool surface area. I view this as phase 1. If I even experience moderate results with it, I'll expand if needed. It may suffice at that level of panel coverage given other posts I have read here. The location is perfect. Faces direct south with almost zero shade.
I do plan to drain them in the winter. I think most of the water would drain out. If not, is it a bad idea to pump some air through the system?
 
Yeah ... they are picky about that. I got mine used off Craigslist. Then there were very few places for me to buy the extra parts that I did not realize were missing.

My setup cost me about $1500 DIY ... Having Heliocol do it would have likely been $4000-$5000.
 
jblizzle said:
Yeah ... they are picky about that. I got mine used off Craigslist. Then there were very few places for me to buy the extra parts that I did not realize were missing.

My setup cost me about $1500 DIY ... Having Heliocol do it would have likely been $4000-$5000.
Click to expand...

You are right about the price. I have Heliocol and my install was about 5K. Mine is installed on a sheet metal rack on our hill.

Sent from my HTC One X using Tapatalk 2
 

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Actually they are really not that heavy. For reference, a 4x12.5' Heliocol weighs 22 lbs empty and 53 lbs full ... spread over 50 sqft, that is just over 1 lb/sqft which is not much. Just standing on the roof could easily be 200 lb/sqft ... depending on one's appetite and shoe size ;)

But if we are talking about a rickety pergola, then of course it could be an issue.
 
Thanks. It is a well built structure. I may add a couple more large anchors to the house ledger board just to be extra conservative, but it is probably fine as-is. According to one of the manuals I have seen online (fafco), a 4X12 panel filled with water weighs just under 70 lbs. Even if I can fit 5 panels up there the overall weight is not going to be that bad, and trust me individuals have point loaded parts of the rafters with good amounts of weight as the metal roof was installed while walking around.
 
Here's what I have to work with after getting the tape out tonight:
The useable roof area on top of the pergola is 12 ft 7 in deep by 25 ft wide.
There is about a 5 inch difference in roof height from house to edge so the pitch is at least there.
A couple questions I need to research, so if anyone already knows based on their own installations please chime in! The first one I can probably find in install manual details.
1) when it comes to roof mounted panels, can I plan to use up almost the entire depth and width or will I need to allow for some anchors/strap connectors in my calculations. It would be great if I could go with 12 ft panels given my dimensions above. Six 4X12's would provide 288 sq ft of panel area, which would equal about 62% of my 15X31 pool's surface area. Even five would put me over 50%.

2) how long of a run to the pump and filter is too long? For this to work and ultimately to end up with something that looks professional, I would plan to run the PVC in two rows directly under my house eaves/gutters and paint to match the trim. Doing that means about 80 feet to get water to the panels and then of course 80 feet back. Due to concrete, I cannot bury them if I locate the panels on the pergola roof. I am sure my pump can handle anything but can always add a secondary if needed. The pump I have now is one of the new pentair intelliflo models. I am wondering about heat loss through that return run, but guessing that in reality the water is there for such a short while that is is negligible. I could be wrong
 
1) Not sure about others, but the Heliocol do not need much room at all for mounting (maybe 3" above and below and nothing on the sides), but the panels are actually 12.5'. Also, it depends how you are going to plumb it. You may need room for pipe along 1 side and either the top or bottom. Plus they are supposed to be slightly tilted to better purge air and drain. I think 12' panels would be a tight fit.

2) I have pretty long runs to 10 panels using 1.5" pipe and a 1HP motor. You will not have a problem, but I would suggest using 2" pipe. The 1.5" was installed and buried by the previous owner of my house. I now step up to 2" every where I can to lower the head loss.
 
I just bought some Techno Solis 4x12 with 2 inch headers panels from poolheatpumps.com (they arrived 3 days ago), they also require 3 inches of spacing between the panels. Price with panel mounting kit only (already had a solar controller from my old panels) was right at $2,700 for 11 panels.

Ike

p.s. I agree 12 ft panels may be a tight fit, I have 14'4" and an concerned about having enough room to mount mine along with inlet and outlet pipes, plus a slight tilt (at 1 inch per panel I end up with almost a foot of rise corner to corner over 50 feet), etc

p.p.s. there are lots of different anchor styles used on the header pipes, ranging from as simple and relatively low profile as a U clamp, ranging up straps and mounting plates that may add 8+ inches to the required height. Side straps may add 3-6 inches or so, depending again on the mounting. For a contrast in installation look at these two sets of installation guides, along with the optional header clamps shown at the front of the first manaual:

http://www.altestore.com/mmsolar/others ... Manual.pdf

vs


www.techno-solis.com/pdfs/TS-Pool%20Solar-Manual.pdf
 
Fafco's require additional space on each end for straps, I can't recall the official distance but you'd probably need at least 4-6". I't also a good thing to have some room to walk around the panels, others may disagree but I don't like stepping on them if at all possible.

My own set up I had to run at least 50' of PVC, probably a bit more, to the far end of the panels and that is up on my garage. I have a 1hp pump and all in all there's no problem with pressure.
 
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