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  • Snow Tolerant PV Mounting

    PV owners who live with snow every winter, soon discover it is devastating
    to production. For roof mounted panels not much can be done, but
    ground mounts are another story.

    Snow often falls in the night, so clearing the panels at sunrise can promote
    production for the next few days. But the classic SW desert array design is
    not set up for convenient snow management. Below are some changes
    to remedy this, which I have tested in real snow. Sn6gap2.JPG





    The first change is to leave a gap between upper and lower panels, for snow
    to slide into and drop down. Experiments showed that a 4 inch gap was not
    wide enough for snow to drop through freely. A 6 inch gap was generally
    sufficient, but still a bit tight for a 6 inch snow fall. The decision was made to
    go for a nominal 8 inch gap. Sn6gap1.JPG
    Sn8gap.JPG





    The gap was found to greatly encourage snow to slide off on its own, since
    it only needed to slide half as far as before. The wider gap absorbed a greater
    fraction of the snow. When manually clearing remaining snow, the snow could
    be pushed or pulled to the nearest opening, only half as far away, and with
    much less physical effort to move half as much snow at a time. After a heavy
    storm my clearing time was reduced from 90 minutes to 40 minutes.

    In addition a greater amount of snow fell under the array instead of down to
    the front. This saved more snow moving, because a buildup at the base can
    block the bottom panel cells and kill production. A 20 inch ground clearance
    was found to require snow blower passes to move snow farther away.

    The next change is to mount panels in landscape orientation. This has been
    recommended before, so that blockage at the bottom would cause bypass
    operation of only 1/3 of a panel, instead of all of it. But my motivation is to
    reduce the distance and effort, and the vertical amount of snow, that must be
    moved to the nearest opening.

    My next change is an array for which the tilt can EASILY and QUICKLY be
    changed on a seasonable basis. Changes were POSSIBLE on my first array,
    but NOT PRACTICAL. The new design has placed the pivot near the array
    center of gravity, so very little force is needed to move even a 24 panel array.
    Use of 6061 aluminum held with 18-8 stainless hardware minimizes weight
    and avoids corrosion problems of a steel support. Actual machine roller
    bearings avoid friction, 6 used in this case to improve support.

    For snow months the panels would be set straight up, for a minimum of snow
    accumulation. This may not completely keep any snow from sticking, but
    experience is that just a TAP on a panel may be enough to clear it and even
    several others adjacent. For that period in the snow latitudes, the production
    is not much less than for the optimum tilt. And sun reflected off
    ground snow favors this position.

    Finally a lot of ground clearance is needed to keep the panels higher than
    accumulating snow. I have mounted panels 40 inches above the ground, hugely
    reducing the chance of needing to move snow farther away.

    With big ground clearance and a snow gap, 2 landscape panels are approaching
    10 feet in height. Stacking more rows than this makes wind stress much greater,
    a problem for any easily tiltable array. And more height is a problem to reach for
    clearing. So my design is only 2 panels high. This in general WILL NOT increase
    the ground space needed for an array, but more or longer rows may be needed.

    To steady the array during storm stress, I have added several adjustable braces.
    These are easily removed from the ground, while making a seasonable tilt change. SnBrace.JPG






    Bruce Roe
    Last edited by Mike90250; 04-18-2018, 11:08 AM. Reason: update title

  • #2
    I live in Phoenix what is this Snow you talk of ?? Seriously you have a nice set up and it looks like you have put a lot of thought into your Solar with the tilt and ground clearance and I think the 8 inch gap is a game changer so congrats.
    9.36 grid tied, Phoenix Arizona

    Comment


    • #3
      Originally posted by bcroe View Post
      PV owners who live with snow every winter, soon discover it is devastating
      to production. For roof mounted panels not much can be done, but
      ground mounts are another story.
      I live in Maine, we get some snow.

      'devastating' is a little over-exaggerating I think. On cloudy days and on snowing days production is down, that is why most systems in my area have battery-banks.

      I have found that Rain-X helps considerably.


      4400w, Midnite Classic 150 charge-controller.

      Comment


      • #4
        Originally posted by organic farmer View Post

        I live in Maine, we get some snow.

        'devastating' is a little over-exaggerating I think. On cloudy days and on snowing days production is
        down, that is why most systems in my area have battery-banks.

        I have found that Rain-X helps considerably.
        Your comment noted, I am sticking to my opinion on this net metering setup. Rain-X might help, but I
        find it quite labor intensive to put on a windshield, and of very limited life. I have more than a thousand
        square feet to deal with. Bruce Roe

        Comment


        • #5
          Originally posted by bcroe View Post

          Your comment noted, I am sticking to my opinion on this net metering setup. Rain-X might help, but I
          find it quite labor intensive to put on a windshield, and of very limited life. I have more than a thousand
          square feet to deal with. Bruce Roe
          And besides, panel mfgs., at least some, and as Russ was told by a panel mgg. or two about four or so years ago, Rainex might damage the ARC coating or interfer with its effectiveness or purpose, and voiding the warranty.

          Anyone else who was around back then have any recollection of that ?

          Comment


          • #6
            Originally posted by organic farmer View Post

            I live in Maine, we get some snow.

            'devastating' is a little over-exaggerating I think. On cloudy days and on snowing days production is down, that is why most systems in my area have battery-banks.

            I have found that Rain-X helps considerably.

            It may also interfere considerably with the ARC coating on your panels and also conveniently void your panel warranty if the panel mfg. finds out about it.

            Comment


            • #7
              Where did all that white foam come from? I see that sometimes in Hawaii and here in Panama when kids soap a water fountain in people yards and public parks. Kind of pretty for a day but kills the grass and flowers. Does keep the damn monkeys away as they freak out a bit like the Park Attendant and home owner.
              MSEE, PE

              Comment


              • #8
                Originally posted by Sunking View Post
                Where did all that white foam come from? I see that sometimes in Hawaii and here in Panama when kids soap a water fountain in people yards and public parks. Kind of pretty for a day but kills the grass and flowers. Does keep the damn monkeys away as they freak out a bit like the Park Attendant and home owner.
                The white helped with contrast on the last picture. Sometimes I load up the array at 10GHZ as a phased array,
                to try and contact your dish. The white provides a ground plane to help focus the beam. K9MQG since 1958

                Comment


                • #9
                  Originally posted by bcroe View Post

                  The white helped with contrast on the last picture. Sometimes I load up the array at 10GHZ as a phased array,
                  to try and contact your dish. The white provides a ground plane to help focus the beam. K9MQG since 1958
                  Here is my QTH so you can aim your Dish at me:
                  38.8976, -77.0364
                  Vanity Call Sign = W3DT

                  73's
                  MSEE, PE

                  Comment


                  • #10
                    Originally posted by sdold

                    Did you get rid of the other callsign? I finally got my 80 and 40 meter dipoles up, we need to try 40 sometime.
                    Run the lon/lat. Then the vanity will make sense. No my callsign has not changed. W3 is a very specific area. You know how to find me. 40 has been pretty good after dark some evenings. Good sun cycle we are in right now.
                    Last edited by Sunking; 04-18-2018, 07:41 PM.
                    MSEE, PE

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                    • #11
                      I have 24 PV panels mounted 45 degrees from the ground with a 3' space in the front from the ground. I use a very soft push broom on the end of a extendable painters pole to clean off the snow. My latest panels are e panels which seem to shed everything better than my Canadian Solar panels.I live in the UP of Michigan

                      Comment


                      • #12
                        Originally posted by gunrackguy View Post
                        I have 24 PV panels mounted 45 degrees from the ground with a 3' space in the front from the ground. I use a very soft push broom on the end of a extendable painters pole to clean off the snow. My latest panels are e panels which seem to shed everything better than my Canadian Solar panels.I live in the UP of Michigan
                        If you're anywhere near Houghton, or some parts of Keweenaw county you've got a lot of experience with snow.

                        Comment


                        • #13
                          Originally posted by J.P.M. View Post

                          If you're anywhere near Houghton, or some parts of Keweenaw county you've got a lot of experience with snow.
                          I am about 80 south of there.

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