Determining the Wind Rating for a DIY Solar Ground Mount

Hey Guys!

I'm constructing a ground mount for my solar panel that is similar to the one found in the video. While putting the system in pretty straightforward, I still live in Florida, so I want to be reasonably sure that the system can withstand some of the weather that we get here. The system is not a grid tie-in, nor does it need to signed off by PE; but I would still like to know what kind of wind rating my system will have (I would like for the system to be able to withstand at least 150 MPH winds). I have an undergraduate degree in Mechanical Engineering, but it's been awhile since I've worked with any structural equations. Do you guys have any recommendations on how to proceed?

Comments

  • mike95490mike95490 Solar Expert Posts: 9,089 ✭✭✭✭✭
    soil analysis to see how stable it is when wet. Then you size the anchors to hold the wind load in n soil You may need to hire an engineer to check or school you in the method. I'm an EE and don't know the mech side too well.
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  • Dave AngeliniDave Angelini Solar Expert Posts: 5,550 ✭✭✭✭✭
    A test commonly used is to calculate the wind force and then weigh the mount down and check the deflection. There should be very little. The 2 inch pipe should not have holes but clamps. At least I have never seen holes in a pipe on the mounts of Pro Solar, UniRac. DPW, or Array Technology.
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  • BB.BB. Super Moderators, Administrators Posts: 31,153 admin
    Unless you have a very large diameter vertical pipe--I would be wanting to see diagonal bracing.

    To give yourself an idea of what level of forces you are looking at:

    http://www.solar-electric.com/lib/wind-sun/SOLARWORLD_280_4.0_FRAME_%2833MM%29.pdf

    Design Loads*
    Two rail system
    113 psf downward
    64 psf upward
    Design Loads*
    Three rail system
    178 psf downward
    64 psf upward
    Design Loads*
    Edge mounting
    178 psf downward
    41 psf upward
    * Please refer to the Sunmodule installation instructions for the details associated with these load cases.

    That 280 Watt panel is about 11.85 square feet. A 64psf loading would be 758 lbs per panel. Put three of those on a rack and that is the equivalent of hanging your car the structure.

    And given that a typical design factor of 10x (the structure has to support ~10x more design load before failure)--You can see that this can add up really quickly (~20,000 lbs to "break" the mount for 3 panels).

    -Bill.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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