placing solar panels on almost flat ribbed metal roof

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placing solar panels on almost flat ribbed metal roof

Postby dgassett on Mon Jan 10, 2011 12:46 pm

I would like to place solar panels on a almost flat ribbed metal roof. Compared to the correct angle for the DFW TX. , area which I think is about 30 degrees, how much power loss will there be? Thanks Doug
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Re: placing solar panels on almost flat ribbed metal roof

Postby tallgirl on Mon Jan 10, 2011 4:40 pm

It's the cosine of the amount that you're off by, more or less. In your case, you might be off by 10% or so.

HOWEVER, you'll gain at a time of year where when your electric consumption will be higher, so it tends towards evening out the electric bill more than if you go with 32* or 33* inclination.

My roof is 26* and I see a really nice pop in April and May.
Julie in Texas

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Re: placing solar panels on almost flat ribbed metal roof

Postby Jamie on Fri Jan 14, 2011 2:38 am

With the 10% loss you also need to factor loss due to crud build-up on the panels if you put them almost flat.
My panels are at 40deg for optimum winter sun and near gravel roads – lots of dust. Last summer I went on the roof a few times to do the job but it was not really required, I think the dust slides off.
Regards
Jamie.
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Re: placing solar panels on almost flat ribbed metal roof

Postby tallgirl on Fri Jan 14, 2011 4:21 pm

Jamie wrote:With the 10% loss you also need to factor loss due to crud build-up on the panels if you put them almost flat.
My panels are at 40deg for optimum winter sun and near gravel roads – lots of dust. Last summer I went on the roof a few times to do the job but it was not really required, I think the dust slides off.
Regards
Jamie.


Dust is mostly washed off by rain, which Dallas actually gets sometimes :wink:

The bigger problem with "flat" is very poor winter performance, but Dallas has plenty hot summers and A/C load support can be invaluable.
Julie in Texas

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