A previous question here was relating wind deflection to drag creation in vehicle solar panel installations. In a residential installation drag is not the issue, but uplift is a critical concern. Since the efficiency of solar panels is affected by temps there will need to be sufficient spacing above the roof. I'd like to know whether a solid or permeable windbreak could provide useful protection for the panels against damage from hurricane force winds or would it instead increase uplift?
1 Answer
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Regulatory requirements will usually stipulate a mounting that will meet uplift conditions.
Uplift is very approximately proportional to velocity-cubed normal to panel (eg under it facing up - so slower than through flow velocity BUT may be close. Halving peak velocity reduces max uplift by factor of V^3 = 8 times ! So a permeable windbreak can help muchly.
NB: All advice worth what you paid for it (or less).
Check regulations.
Ask an engineer qualified to certify installations in your area.
Drag ~~~~= 0.5 x density x Area x Drag_Coefficient x Velocity^3
Density at sea level = 1.2 kg/m^3.
For A in m^2, V in m/S, g = 9.8 ~= 10
Force in kg ~= 0.06 x A x V^3
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$\begingroup$ And hopefully :-( the requirements in hurricane-prone regions were written to withstand said wind speeds. $\endgroup$ Jan 13, 2016 at 15:13