[RE-wrenches] Solar World Wind Damage

[Chris Daum]

Makes you wonder if we just couldn't get a manufacturer to make beefier
modules for really harsh sites, eh?
 
--Chris @ the Oasis MT

  _____  

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
Behalf Of Ray Walters
Sent: Thursday, January 12, 2017 5:22 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Solar World Wind Damage


Chris & Dana;

Our site is a mountain in Wyoming and does have some focusing effects, so
maybe 170 mph is possible.  Are your arrays using top down clamps?  I think
that is apparently stronger, also possibly the 2011 Sanyos look to have
beefier frames.  However,  I looked at their spec sheet and they're only
rated at 60 PSF (less than the SWs).  From my measurements here of Solar
World 4.0 frames, I'm seeing a flange thickness of approx 1.3 mm, while an
old Siemens SP 75 has 1.8 mm thick metal.   
I'm coming up with a fix for the Solar Worlds: 3/4 x 3/4 Stainless steel
Angle fits just inside the lip of the module, and will distribute the forces
more evenly.  The question then is, are we just going to lose the glass
next?  Anyone have a currently available module that is beefier?  I may
recommend we swap the whole array out, if we are indeed exceeding the design
of the Solar Worlds. 

Thanks,

R.Ray Walters

CTO, Solarray, Inc

Nabcep Certified PV Installer, 

Licensed Master Electrician

Solar Design Engineer

303 505-8760
On 1/12/2017 2:39 PM, Chris @ The Oasis wrote:


Wrenches:  We have a  ~70KW ground mounted array on the Rocky Mountain front
near Choteau, MT.  Springs winds are not unusual with 150 to 175 MPH gusts.
The system was installed in 2011 (with Sanyo 215W modules).  No problems
yet; we certainly over-engineered the racks, knowing what high winds there
are!
 
Chris Daum
Oasis Montana Inc.
406-777-4309
406-777-0830 fax
www.oasismontana.com 
  


  _____  

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
Behalf Of Ray Walters
Sent: Thursday, January 12, 2017 2:16 PM
To: RE-wrenches
Cc: Sefchick, Steve
Subject: Re: [RE-wrenches] Solar World Wind Damage


Hi Bill;

Solar World customer support did come through yesterday with flying colors.
They got hit by a big storm in the North West.  Right now though, they are
saying that we exceeded the 64 PSF rated  loading to the back of the module.
I've pointed out that that would correspond to over 170 mph winds, so I'm
not quite ready to concede the warranty.   Their engineering team is
reviewing my information.  
As always, the Wrench list experience is invaluable.  Are 170 mph winds
possible, outside of a tornado or hurricane?

Whether or not Solar World stands by their product in this extreme
situation, I definitely stand by my installations. I'm taking a snow cat up
to replace and reinforce the modules next week, then hopefully get a little
help from my supply chain after.  My repair costs will be many times the
cost of one replacement module anyway. 

Yes, the 33 mm vs 31 mm refers to the module thickness.  I don't have a
version 2.5 frame to check the flange metal thickness, and it is
conspicuously absent from the specs.  I have a good micrometer, and I will
compare metal thicknesses of several module brands, because with all the
cost cutting, many module manus seems to be using thinner metal lately.  As
Jay pointed out, we're bolting much bigger modules down with much weaker
flanges, and the same hardware we used on a 75 w module, so its not entirely
surprising to start seeing high wind failures.

R.Ray Walters




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