storms and solar panels

Dapdan
Dapdan Solar Expert Posts: 330 ✭✭
in General Solar Power Topics #1
Hi all,

I was just wondering how do you guys deal with storms and your roof mounted(or otherwise) solar panels. Of course those with insurance perhaps don't need to worry. However some off grid folks may not be so fortunate. I am in a different category. The local insurance ppl don't have a clue, subsequently I have not received a quote.

My plan is quite simple. In the event of a Hurricane I remove all panels and store them in my concrete basement until the event passes. I hope to have a more savy system where the panel are mounted on a garage concrete roof and then install plywood over them in case of a storm event.

Cheers...
Damani
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Comments

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #2
    Re: storms and solar panels

    That's a good plan, strip the array for hurricanes

    As for what I do, we can't put panels on a roof without an structural engineer approving ( and hence reviewing ) the mounting structure and the structure its attached to.

    In my part of Florida, we have to meet a 120mph wind code, the concern is uplift similar to a wing of a plane. As long as the structure and mounts can hold the panels to the roof, the home is already built to meet the 120mph code.

    My systems have gone thru 4 hurricanes and on tornado less than 1/2 mile from the house ... most I have lost is a few roof cap shingles, peak gust winds were about 90mph
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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #3
    Re: storms and solar panels

    Hey gup,

    I am actual a Civil and Structural Engineer, the structural integrity is not a problem for me nor is it a major concern. My major concern is fly debris which cannot be predicted since other ppl may not be as structurally safe as yourself. Example, when i went away to the states for 3wks last year hurricane season i put up the panels and shuttered my house-just in case. With my panels costing nearly $9000 I can take any chances with flying galvanise sheets or 2x4.

    Cheers...
    Damani
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Re: storms and solar panels

    i agree with you on covering them, but with hurricane force winds it can drive things right through plywood too. the plywood would most likely prevent most damages from occurring i think, but should not rest squarely on the pv surface as some flexing of the plywood would be needed. this would allow the plywood to absorb the impact better without transference to the pv. against the frame would be ok, but this doesn't afford much flex to the plywood so some kind of standoff is needed and can simply be a lining of narrow plywood strips around the edge of the frame as an example.
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #5
    Re: storms and solar panels

    If we had a CAT3 or greater heading for Lakeland, I'd strip the roof ... I can do it in about 1 day with a helper if need be, all the wiring is now MC connectors and I have built a removable platform for the truck to make access to the roof simple.
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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #6
    Re: storms and solar panels

    Hey niel,

    Let me outline my ultimate plan in a little more detail. It involves the erection of my panels on a concrete roof over a two bay garage. The roof will have at least 2' parapet wall all around with a 3x4 strip of pine on the inside face of the wall all the way around. The panell would not protrude beyond the horizontal edge of the wall and would be under the inside wood strip. Frame would be constructed to achieve the 13degree attitude and be below the top of the wood strip as necessary.

    Once a storm event requires protection the already prepared plywood would be screwed onto the internal wood strip so that the edge of the plywood sits on the top of the parapet with out overhanging. Of course there would be intermediate supports to carry the weight and hold down the plywood.

    Cheers...
    Damani
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #7
    Re: storms and solar panels

    In your location, I'd put the effort into making easy removal. Wood anything is no match for an island hit of an hurricane. I'm 70 Miles inland so I don't have the same concerns you have, also I would guess you have much more things flying around or trees crashing down ( no trees within falling distance of my home )
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #8
    Re: storms and solar panels

    dapdan,
    i am having trouble picturing this so if you have a photo you can upload that would be nice. sg is right that the full force of a hurricane will spell trouble and though the plywood may be better than nothing it may not stop the damages from occurring.
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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #9
    Re: storms and solar panels

    good plan guppy,

    The ultimate protection would be to remove them and store in a basement/bunker. Of course i was expection a major even CAT 3 and up i would remove mine and store in my concrete basement.

    Cheers...
    Damani
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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #10
    Re: storms and solar panels

    niel,

    I cant do that since my garage is not built yet. but essentially the panel would be mounted on the concrete roof of the garage that has a small parapet wall the(short wall built on perimeter of the concrete roof). so the panels would not be exposed on the side since the wall is there. the protection would consist of a plywood covering essentially on top of the parapet wall(not overhanging though) and structural fixed to the wall and the concrete roof so that you could even walk on it. the finish structure will not expose any part of the panels or even the concrete roof it self.

    I dont know if this is any clearer

    Cheers...
    Damani
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #11
    Re: storms and solar panels

    Sounds like you are building a little concrete bunker with a plywood top (below the parapet walls).

    Are you planning on making the panels so they can lay down flat, then cover with the wood?

    Sounds like a good solution. The question eventually becomes is the labor to remove, store, and re-install the panels easier than installing your plywood false cover over panels laid flat on the roof (and the possible damage from having to move plywood sheets around.

    My area has no such wind (or weather problems in general). Just earthquakes--which thankfully are few and far between (and always happen in nice weather :p ).

    I would be a bit concerned that the wind blowing over the parapet walls might be able to find an edge/seem to get under the plywood+panels and they just unzipper with lots of potential for damage.

    In various applications when you don't want "lift" from high speed air flow--so they install spoilers to "dirty up the airflow".

    They are used on aircraft to kill lift (such as gliders to have a steep approach to landing without gaining too much speed) or on roofs of NASCAR race cars so that if the car begins to spin--as it turns sideways to the wind flow, the stall strip rises and breaks up the airflow along the left and right door/ridge line--the roof then does not act like a wing and lift the car off of the ground and cause it to flip because the air is no longer flowing cleanly.

    Here is one video the clearly shows how they can work on a race car (youtube)

    I wonder if you installed some sort of spoiler panels (perhaps you only tilt&lock them up when a storm is due so you don't get shadows during normal operations) around your parapet if it would help breakup the airflow and lessen the possibility of the wind pulling up the plywood and panels? Perhaps--this is way to "out in left field" thinking for a hurricane.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #12
    Re: storms and solar panels

    Hey bb,

    I plan to install panel with a fall such that the highest panel is still under the top of the parapet wall.

    The open area of the roof should be approx 16'x16' which is 8 sheets of ply and would be store in the garage. So i dont expect labour to be to much since i can move them to the roof myself.

    Remember i plan not to have the sheets overhanging the parapet walls. I also plan installation with screw, lag bolts or even carriage nuts which should be pretty secure.

    I expect trubulence above the flat roof since the structure is squares and would have sharp edges so eddies would result and overall lift would be reduced.

    I had always planned on building a concrete roof for the garage so my additional cost would only be the ply which I would already have since I would have used them as formwork to form the underside of the concrete slab.

    Cheers...
    Damani
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