Dirt buildup along solar modules' bottom rail is a real problem in locations
that have a lot of airborne dust and dirt and do not get regular rainfall.
Los Angeles gets very little rain from April to November. This year I let
dirt build up on my old array from January until August. One group of
modules is at 10 degrees tilt. The other group is at 18 degrees tilt. Both
groups of modules had the same amount of bottom rail dirt buildup. There was
about 1 inch of sun-blocking dirt at the bottom rail, but not up to the cell
tabs, and then uniform dirt on the rest of the modules. See
http://www.solarsolar.com/ I sprayed the array with a very weak solution of
Turtle brand ZipWax car wash, wiped it with a sponge mop, and then rinsed
it. Total time spent cleaning the array was less than 10 minutes. Power
increased 10%. Next summer when I clean the array, I will just dry wipe the
dirt at the module bottom rail and report the difference.
----- Original Message -----
From: "August Goers" <[EMAIL PROTECTED]>
To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org>
Sent: Tuesday, November 04, 2008 6:43 AM
Subject: [RE-wrenches] Flat Panels
Wrenches -
Lately we've been called out to repair or upgrade several ~5 year old PV
installations in the Bay Area. It is always interesting to see how they're
holding up. Apparently it was common to mount panels completely flat
(horizontal) on flat roofs back then. This poses a serious problem because
the module frame lip catches water and dirt and prevents the panel from
washing off in the rain. See a photo here:
http://luminalt.com/temp/flatpanel.JPG
Note that two of those panels were broken by a baseball, but you can still
see the dirt buildup on the adjacent panels right across all three rows of
bypass diodes.
Any ideas on what percentage loss that dried dirt is causing?
Lesson learned: never tilt panels below 5 degrees, preferably 10 degrees.
Cheers,
August Goers
Luminalt Energy Corporation
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