Yeah, their solar panel was a thin film rolled into a tube.  They slid that 
into a glass tube and injected some kind of oil in between.  The modules were 
arrays of tubes with a gap between tubes.  

They were better at constant out put, but they were really bad on watts per 
square foot and dollars per watt.  My son bought truckloads of them when they 
went bankrupt.  

From: Cameron Crum 
Sent: Tuesday, September 22, 2015 8:01 AM
To: [email protected] 
Subject: Re: [AFMUG] The dreaded annual "how to keep snow and ice off my solar 
panels" thread

Wasn't this sort of Solindra's idea? Tube shaped solar "panels" with a white 
reflective surface underneath so that no matter the angle some part of the 
panel was always getting light. It took more "tubes" but removed the hassle of 
having to worry about angles and time of day.  



On Tue, Sep 22, 2015 at 8:23 AM, Chuck McCown <[email protected]> wrote:

  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 <[email protected]> 
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





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