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This has been an issue on some of our systems, but strangely not
most of them. I have not figured out a correlation yet. We have
dozens of pole mount and roof systems that shed snow as soon as the
sun comes out, and then some that ice up and are a real mess all
winter. The only difference I seem to see is wind speed. <br>
Has anyone ever tried insulating the backs of the modules in the
winter? (of course that would be removed in the Spring) Or what
about a black module backing that would pick up snow reflected light
in the winter, but not in the summer?<br>
<pre class="moz-signature" cols="72">R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760</pre>
<div class="moz-cite-prefix">On 3/27/2015 11:11 AM, Kristopher
Schmid wrote:<br>
</div>
<blockquote
cite="mid:CAJB-iS-BODbEm__E7XP_60+MSay_o--QcnhqUUwrzPawLZ2Kgg@mail.gmail.com"
type="cite">
<div dir="ltr">Ignoring the effect of roofing material friction
and tilt angle, i would surmise that the array being
"open-backed" would reduce heat build up and actually decrease
the snow shedding ability.<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Mar 27, 2015 at 11:36 AM, Dave
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:dave@independentpowerllc.com" target="_blank">dave@independentpowerllc.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div link="#000000" vlink="#000000" lang="EN-US">
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">BTW
Dan. I have designed and installed power sheds here
in the north with tilt up arrays using adjustable
leg sets that allow up to 80 degree tilt angles!
Pretty ugly if it's staring you in the face, but
quite effective when the bottom of the array is
directly over the eave of the roof. Allow 18" or so
distance from roof to bottom of modules to allow the
snow on the surface of the roof to be cleaned
occasionally with a roof rake. Adjustable legs will
allow experience to be your guide going forward on
how much of a tilt is needed (and tolerated
appearance wise). Of course the wind loads are
severe with a design like this and must be managed.</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dave</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p>
<div>
<div style="border:none;border-top:solid #b5c4df
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
RE-wrenches [mailto:<a moz-do-not-send="true"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org"
target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>]
<b>On Behalf Of </b><a moz-do-not-send="true"
href="mailto:dan@foxfire-energy.com"
target="_blank">dan@foxfire-energy.com</a><br>
<b>Sent:</b> Friday, March 27, 2015 12:00 PM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Tilt Racking
vs Roof Mount for Shedding snow</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black">My
customers neighbor has 1.1k of 110W panels on a
tilt up rack set at about 45° (Some 20° from the
roof). Her array pretty much stayed clear all
winter with minimal futzing. My customer has a
7.2k array (Four rows of six) in portrait, mounted
on unirack solar mount on an asphalt tile roof at
around 45° (Off Grid), on an unheated garage. My
customers panels got a thin coat of ice on the
array early on that held some 12'' of snow all
winter. We did set it up so the bottom two rows
were on their own CC and could be cleared from the
ground, but they never did totally clear. The
neighbor now wants to expand her system, is
willing to build a shed for the array, but wants
me to elevate the array as far off the roof as
possible (and minimize costs). I'm working on my
diplomacey here. I suggested it might be a
combination of factors that contributed to my
customers array not sheding, but the neighbor
insists it has something to do with the array
being open backed. I offered to put it out to the
group for opinions. Thanks db<br>
</span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"><br>
Dan Brown<br>
Foxfire Energy Corp.<br>
Renewable Energy Systems<br>
<a moz-do-not-send="true"
href="tel:%28802%29-483-2564"
value="+18024832564" target="_blank">(802)-483-2564</a><br>
<a moz-do-not-send="true"
href="http://www.Foxfire-Energy.com"
target="_blank"><span style="color:windowtext">www.Foxfire-Energy.com</span></a><br>
NABCEP #092907-44</span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"><img
src="cid:part6.00050704.02090403@solarray.com"
border="0" height="107" width="224"></span></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span></p>
</div>
<blockquote style="border:none;border-left:solid blue
1.5pt;padding:0in 0in 0in
6.0pt;margin-left:6.0pt;margin-top:5.0pt;margin-bottom:5.0pt">
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black">--------
Original Message --------<br>
Subject: Re: [RE-wrenches] Tilt Racking vs Roof
Mount for Shedding snow<br>
From: "Dave" <<a moz-do-not-send="true"
href="mailto:dave@independentpowerllc.com"
target="_blank"><span style="color:windowtext">dave@independentpowerllc.com</span></a>><br>
Date: Fri, March 27, 2015 10:32 am<br>
To: "'RE-wrenches'" <<a
moz-do-not-send="true"
href="mailto:re-wrenches@lists.re-wrenches.org"
target="_blank"><span style="color:windowtext">re-wrenches@lists.re-wrenches.org</span></a>></span></p>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dan,</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">What
do you mean by "tilt up racking". Would an
example be a rack that adds 15 degrees to a
5/12 roof? Good idea (as long as wind load
is taken care of) for cold snow country
(certainly for off grid) to get the tilt
angle higher which helps with snow shedding.
BUT if it's super cold like this winter here
in northern New England nothing helps as
much as a snow rake. </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">On
a side note. I had a couple of monitored
grid tied systems with second story roof top
arrays that produced very little power from
January through second week of March. 80%
less kWh than similar first story roof top
arrays where the homeowner raked off snow.
It was so cold that in one period this
winter that it did not get over 30 degrees F
for 48 consecutive days here, with many
nights at 15 to 30 below zero. February was
the coldest on record (since 1886) with
temps that were 15 degrees below average for
the month. No snow shedding going on at all.
</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">On
another type of array. My adjustable ground
mount here set at 90 degrees had a great
winter as I regularly saw 1,750 to 1,950W
out of my Apollo CC from a 1,440W array on
sunny days because of MPPT and the
reflective bounce of sunlight off the snow
in front of the array. I never have to touch
those modules from mid November, when I tilt
them to 90 degrees, until after it stops
snowing significantly (mid April usually).</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Best,</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dave</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">David
Palumbo </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Independent
Power LLC</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">462
Solar Way Drive</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hyde
Park, VT 05655</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a
moz-do-not-send="true"
href="tel:802-888-7194"
value="+18028887194" target="_blank">802-888-7194</a></span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
<div>
<div style="border:none;border-top:solid #b5c4df
1.0pt;padding:3.0pt 0in 0in 0in">
<div>
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">
RE-wrenches [<a moz-do-not-send="true"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org"
target="_blank"><u><span
style="color:blue">mailto:re-wrenches-bounces@lists.re-wrenches.org</span></u></a>]
<b>On Behalf Of </b><a
moz-do-not-send="true"
href="mailto:dan@foxfire-energy.com"
target="_blank"><u><span
style="color:blue">dan@foxfire-energy.com</span></u></a><br>
<b>Sent:</b> Friday, March 27, 2015 8:19
AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> [RE-wrenches] Tilt
Racking vs Roof Mount for Shedding snow</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
</div>
<div>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:black"> </span></p>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black">Hi
Guys, I have a customer who seems
convinced that tilt up racking sheds snow
better than conventional roof mounted
arrays (irregardless of angle or panel
manufacturer). Anyone else find this is
true? Thanks db</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black">Dan
Brown<br>
Foxfire Energy Corp.<br>
Renewable Energy Systems<br>
<a moz-do-not-send="true"
href="tel:%28802%29-483-2564"
value="+18024832564" target="_blank">(802)-483-2564</a><br>
<a moz-do-not-send="true"
href="http://www.Foxfire-Energy.com"
target="_blank"><u><span
style="color:blue">www.Foxfire-Energy.com</span></u></a><br>
NABCEP #092907-44</span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"><img
src="cid:part6.00050704.02090403@solarray.com" border="0" height="107"
width="224"></span><span
style="font-family:"Verdana","sans-serif";color:black"></span></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:black"> </span><span
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<br>
-- <br>
<div class="gmail_signature">
<div dir="ltr">Shine On!<br>
<br>
Kris Schmid<br>
Legacy Solar, LLC<br>
864 Clam Falls Trail<br>
Frederic, WI 54837<br>
<a moz-do-not-send="true" href="http://www.legacysolar.com/"
target="_blank">www.legacysolar.com</a><br>
715-653-4295<br>
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Licensed Wisconsin Master Electrician<br>
BSEE</div>
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