Have you tried inverted panels?
(Most on this list have probably heard this story before.)
I had a mountain top site that lost about half of its power production after a
big storm. Flew over it and found that one set of panels had come loose at the
top and flopped over so they were facing the ground at an angle. Probably 30
degrees from horizontal.
The snow on the ground was reflecting the sunlight up into the panels and they
were actually putting out a surprising amount of power. Could always count on
them being alive the day after the storm. I figured if I ever had to do an
extreme high reliability site, I would build a white reflector on the ground
and use inverted panels over it. Have to work on the geometry of the reflector
and panels but it could be a useful emergency source of power in areas where
snow and ice cause problems. You normally have the clearest skies and
brightest sun the day after the storm.
From: Steve D
Sent: Monday, September 21, 2015 10:37 PM
To: af
Subject: Re: [AFMUG] The dreaded annual "how to keep snow and ice off my solar
panels" thread
Vertical panels is something we're experimenting with as well. Started
ignoring "optimum" angles years ago and pushed the panels as steep as they
would go with existing hardware (about 80-85) but it's amazing what will still
stick. Last winter we had a freezing rain that built up ice on the bottom
metal lip around the glass and the wet sticky snow that followed built up 4-5
inches on top of that, even at those angles. (Last year was honestly the worst
year for our solar sites in the last few years.)
We're in the process of beefing up and extending the angle brackets for the
racks at two sites so that we can go all the way vertical. I think snow will
be fine at one of the low elevation sites, but the high elevation I still half
expect to see them covered in hoar frost.
On Mon, Sep 21, 2015 at 1:17 PM, Eric Kuhnke <e...@kuhnke-international.com>
wrote:
If you're off grid and at latitude 35N or higher... The one thing you should
care about is cumulative kWh production in December and January.
Try putting the panels at an 85 or 90 degree tilt (yes, really) facing due
south. You will produce a lot less in June/July but your winter production will
be maximized. This also has the effect of ameliorating snow and ice buildup
thanks to gravity.
The US DoE NREL and other sources have a lot of research on latitude vs.
angle tilt of solar panels. Ignore everything intended for gridtie applications
and stuff like "tilt the solar panels at the same angle as your latitude".
There are some online calculators like pvwatts that will show you your December
and January production for a 45 degree tilt vs. an 85 degree tilt.
On 9/19/15 11:05 PM, Steve D wrote:
Maybe it's Saturday night exhaustion talking, but piping the exhaust from a
standby generator toward the back of solar panels a bad idea? I'd expect it to
not put heat on the panels in the summer except it's weekly exercise cycle but
that shouldn't be too bad? LP too so shouldn't be any soot. Or would this
just create one little hole of open panel and a pile of ice? Bad in general
for the panels?
If I did this again, I'd put the damn thing directly under the panels...
these Onan's get stinking hot. My little "cool running", comparatively
speaking, portable yamaha's will melt a two foot radius of snow around them if
they run for a good length of time, all this heat going to waste! The Onan
would probably clear the whole rack if it was sitting right below it.
Grumble grumble... snow... something, something, curse words...
Cheers,
Steve D
