Saturday, August 18, 2012

Bleg: Thin Film Solar Modules on Aging Barn Roof

A quick question: I'm starting to research installing solar at our place near Ithaca (always my intention from when we bought it, but other projects had to happen first).

It seems to me appealing to put the solar power on the barn rather than the house:
  • It has a much larger area (ie more power)
  • The cosmetic impact from the road will be lower
Since the barn roof structure is not that heavy, it probably makes a lot more sense to apply flexible CIGs modules (eg like these Global Solar modules) than to use conventional modules.  These flexible modules are generally glued to a metal roof (eg with mastic).  So one question is whether folks have experience with these modules and prefer one brand to another?

Secondly - the sheet metal on the barn roof is a few decades old.  While the roof isn't in imminent danger of failing, about 50% of the roof area now looks rusty and about 50% still has the galvanized surface.  I've already had a contractor offer to cover the roof with an aluminized asphalt product to extend the life of the metal.  Clearly, it's not desirable to attach solar modules to metal with a noticeably shorter life than the modules.

One idea that occurs to me is to use an aluminized asphalt product to adhere the modules to the metal, and cover the whole roof at the same time in the interests of preserving it.

Does anyone have any experience with a similar situation?
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11 comments:

  1. sunbeamAugust 18, 2012 at 9:12 PM

    No experience here, but a comment.

    It is possible you are concerned about the look of your property, or even that zoning laws somehow (or more probably your wife) could object.

    But you live in a rural area from what I understand.

    You can put them anywhere you wish at ground level. Me personally I wouldn't put there anywhere it was hard to access or install in the first place. I'd put them up on poles facing south at whatever angle is best (45 degrees?).

    Then build a little shed right by it to put my batteries and inverter (think that is what it is called) in. Probably make the shed a little oversize to hold other junk (I'm a hoarder). Run a big line to the house and your well pump.

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  2. QuadriviumAugust 19, 2012 at 6:34 AM

    Have you considered ground-mounted PV? If you have the space, a system like First Solar's might be worthwhile. That way, you can have somewhat easier maintenance and installation (usually, the metal posts are sufficient - no need for concrete). Shading and aesthetics are important, too.

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  3. trojanhorseAugust 19, 2012 at 7:36 AM

    My first concern would be to make sure that it was (the sheet metal) weere securly screwed or rescrewed to the rafters. After decades in the sun and cold one should expect loosening. A good penetrating rust paint and then your aliminized asphalt.

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  4. Dan ArguellesAugust 21, 2012 at 4:37 AM

    I have plenty of experience! You can stick those modules on a new sheet of metal and fasten them to the old metal of the barn roof structure with polyurethane adhesive or you can fasten the new sheet metal with bolts. That way you can remove them for maintenance or salvage if needed.

    A likn is provided showing similar use with roof tile:

    http://issuu.com/artezanos/docs/hybrid_tipv_goodman


    Dan

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  5. Dan ArguellesAugust 21, 2012 at 4:38 AM

    Sorry, I'm not sure if I posted the link earlier:


    http://issuu.com/artezanos/docs/hybrid_tipv_goodman


    Dan

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  6. Stuart StanifordAugust 21, 2012 at 11:30 AM

    Dan - thanks, that's a very interesting suggestion.

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  7. Keystone Contracting Corp.August 24, 2012 at 1:02 PM

    I would go with what Dan posted, it seems reliable and on point.

    -Adam Ahmed
    Roofing Brooklyn

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  8. Rodney OrtonOctober 8, 2012 at 8:25 AM

    It’s very alarming to know that 50% of your roof is already close to structural failure. Actually, using aluminized asphalt products goes way beyond just cosmetics. The asphaltic oils in the base coating are protected from the sun’s rays, which are reflected by the aluminum, preventing the base oils from “cooking”, and then cracking. The aluminum coating will also reduce indoor temperature by as much as 15-20 degrees Fahrenheit.

    Rodney Orton

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  9. Stuart StanifordOctober 8, 2012 at 5:29 PM

    Rodney - my barn looks pretty good by the standards of barns round here!

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  10. AnonymousNovember 6, 2012 at 3:18 PM

    Always wanted a barn.

    -Sharone Tal
    Solar New Jersey

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  11. AnonymousApril 18, 2013 at 1:53 PM

    So... what did you go with? Did you try Dan’s suggestion? Myself, I would go with the other’s suggestion and have a ground-mounted one, if not for the convenience of repairs and maintenance. But if you were planning to repair the barn roof as well as add the solar modules in, I would go with Dan’s. It’ll be easier to replace afterwards if you have a separate layer for metal between the barn roof and the modules.

    Cody Charlebois

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