Thanks for the input so far on reducing heat issues. I have the two inch aluminum square tubing on hand and ready to install, but when I finally heard back from Renogy, they suggested placing some insulation between their 200 watt panels and the metal roof beneath. Does this make any sense? If so, can anyone recommend a type of insulation that would survive the sometimes harsh elements? Again I thank you.
Insulation under panels?
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Bluedog225
Texas
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I’m not familiar with your other post. But airflow under panels is helpful. Really depends on exactly what you are doing.
In general, foam insulation and anything similar outdoors can degrade and get picked away by birds and critters. And some foam has a metal face that may complicate the issue electrically.
In general, foam insulation and anything similar outdoors can degrade and get picked away by birds and critters. And some foam has a metal face that may complicate the issue electrically.
timselectric
If I can do it, you can do it.
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I agree.
Let the air flow freely, under the panels.
I guess that the square tubing is going to be your framing?
Let the air flow freely, under the panels.
I guess that the square tubing is going to be your framing?
BradCagle
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So I saw your other thread. You tested your panels on the ground propped up on a bucket, and they produced 160w. Now they are on your roof and you're getting 90w.
OK so it's very possible you had better control of the proper angle, and direction of the panels when testing on the ground. You put them on your roof, now they are fixed in the direction/angle of your roof, no fine tuning.
If you really think the large loss is due to heat. Well spray them down with the water hose, and see if you get back to 160w. I doubt it.
timselectric
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The panels will shade the roof. It will actually stay cooler, with the panels and air circulation.
Not using any framing. Panels are now screwed directly into the metal roof. Thanks for your response.
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efficientPV
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Doesn't make any sense to me unless they were talking about electrical insulation.
Lt.Dan
Solar Wizard
Yeah you definitely need to space them off the roof. They NEED airflow underneath them. Minimum 2", but the more the better, so long as your roof can sustain wind loads with a larger gap.
Thanks. Wish I had kept a better eye on this thread. They are installed on a metal roof. Total clearance would be 2" from the spacers, and 5/8" more from the mounting brackets. Should that be enough, or do I need another 3/8" or so? Also, what does NEC/NFPA stand for?
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Square tubing in 4" sections as a spacer for each bracket.
timselectric
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NEC - National Electrical Code
NFPA - National Fire Protection Association
Angle may have been off a little, but the panels faced the same direction as they would when mounted on the roof. Plus, it was late winter/early spring when I tested them.
I'm in North Carolina, not far from the coast, and we typically see one serious hurricane every other year or so.
Lt.Dan
Solar Wizard
This is why engineers get paid to make wind load calculations on different roof designs, to make calculated suggestions on how to mount the panels on a given roof. Another reason I did not do my roof solar myself.
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