benn,
yes, this has happened to me on two sites (until i learned this type of mount does not work). one had mitsubishi modules and another evergreen modules. other colleagues here have had these painful "learning opportunities" too. both of these jobs were for customers who insisted on roof, rather than my suggestion of pole mounts. after the damage, the the pictured system was changed to a problem free pole mount. there was no warranty coverage as this was a installation design error, not a module manufacturing defect.
this is nothing other than snow, which sits on a shallow angle mounted module. compression, and the daily freeze/thaw cycles change the bottom layer to ice. subsequent snows add weight, and the downhill creep tears the bottom edge off the module. then the unsupported glass breaks.
shallow angle mounts, 6/12 and below are usually problematic. steep angle mounts (steep angles shed the snow) 12/12 and above are usually not a problem. between 6/12 and 12/12 is a grey area depending on specific conditions.
these are not "massive" snow events, just normal winter conditions. i live in the mount shasta area of northern california.
todd
On Wednesday, December 9, 2015 2:11pm, "Benn Kilburn" <b...@skyfireenergy.com> said:
So was this a result of some snow accumulation, then melt/freeze cycles then more snow accumulation which forced the ice build-up down onto the lower frame edge? Are you aware/can you clarify what led up to this?
I am aware of massive amounts of snow fall in mountain regions (not exclusively). Is that where this was?
except, "let it melt" on shallow angle roof mounts often yields this:
todd
On Wednesday, December 9, 2015 1:48pm, "Benn Kilburn" <b...@skyfireenergy.com> said:Dana,SESA (Solar Energy Society of Alberta) has been providing a great service to anyone interested in Solar Energy for many years. One project touches on what a PV system will produce at various angles here in Edmonton and the result of snow removal, or not, in particular.
I've been meaning to reply to this with a link... here it is...
http://solaralberta.ca/content/alberta-solar-performance-dataNow, assuming we are talking grid connected systems rather than off-grid when the energy is 'really' needed.The rational that this reference array system supports is that during the 'snow months' while the days (and sun hours) are short and there is little potential energy to harvest anyway, there is not a huge, if any, benefit to pay anyone or risk safety to bother clearing snow off of modules in the winter.Of course your site will have its own variables, but if you make some estimations on days of snow cover and peak sun-hours you are missing out on then you can calculate the potential loss in kwh and dollar value that you are loosing due to snow cover.If someone's time is being paid to remove the snow then it is most likely not worth the cost considering the $ value of the potential kwh lost.Our general consensus is that if removing the snow presents any challenge, especially to safety, then it is best to just leave it to melt.Not really an answer to your question... but another perspective to consider.
Benn KilburnCSA Certified Solar Photovoltaic Systems Electrician, SkyFire Energy Inc6706 – 82 Ave NW | Edmonton, AB | T6B 0E7![email]()
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On Thu, Dec 3, 2015 at 3:05 PM, Dana <d...@solarwork.com> wrote:
For a flat roof, 35° rack mounted large array in snow country what have people done for snow removal other than hand shovel it out?
We thought of a dark roof material to start, & we can’t snow blow as there will be sidewalks & people below on all 4 sides.
We are trying think this out in advance!
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Dana Orzel
Great Solar Works, Inc - NABCEP # 051112-136
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