<div dir="ltr"><div><div><div>Bill<br><br></div>Kids do not try this one at home! Which of course will make the kids want to do it even more. <br><br>I would say it is a bit risky to chance using hot water to clear snow. Every time you do this is putting stress on the components and increasing the risk of delamination issues down the road. Water working it's way into cavities and refreezing can lift sidewalks and destroy foundations. Delamination can cause a fire by allowing current leakage through the frame, so it can be worse than just having to replace your modules. Granted the modules already see a lot of thermal stresses and have been tested for it (UL listing is no indication of the ability to last 20 years in the field) , but there is no reason to place more stress than needed on them. IMHO modules still cost too much to use as a disposable science project, although I would love to have some donated for a long term study! <br>
<br></div>On another extreme note, I was once involved in a solar drag race using straight PV power to run a motor, no storage devices allowed. One of the crews used a fire extinguisher to cool off the modules to get more power out of them. I cringed because they were using very expensive modules with the maximum efficiency and I expected the glass to shatter. It did not, but who knows how the movement of different materials did for the longeviity of the project. By they way they lost the race to a high school team that engineered a better motor drive system! I wonder who is using those modules right now.....<br>
<br></div>Bill<br><div><div><br> <br></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Apr 18, 2013 at 10:23 PM, frenergy <span dir="ltr"><<a href="mailto:frenergy@psln.com" target="_blank">frenergy@psln.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div style="font-size:14px;font-family:Capitals,sans-serif;word-wrap:break-word" bgcolor="#ffffff">
<div><font face="Times New Roman" size="3">benn and interested
others,</font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<div><font face="Times New Roman" size="3">
Just a side note due to benn's comment about cold water on a hot panel possibly
resulting in cracked glass. </font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<div><font face="Times New Roman" size="3">
My 45 degree tilt, roof mounted shop array (5KW, Solarworlds) gets covered with
snow in the winter at times...when I need the power the most (off-grid).
Even at that tilt, there are times when it takes a few days to slide. I
have a 50 Gal tank of hot water in the shop heated from the woodstove often that
time of year. The temptation was great, should I do it??</font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<div><font face="Times New Roman" size="3"> I
just happen to have a failed Kyocera 80-85W mod so I covered it with a foot of
snow, air temp at about 15 degrees F, connected the hose to my hot water supply
bib, turned on the too-hot-to-touch hot water (got it running hot off to the
side of the mod first) and when the water started to steam I pointed it at the
snow covered module from about 4 feet. It took about 1-2 seconds for
that hot water to penetrate the snow and hit the glass...I spiraled out from
that point until most of the snow was gone. Result: glass
AOK.</font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<div><font face="Times New Roman" size="3">
Yes, I then proceeded to clear my entire array of snow to collect many
ground-covered-snow-reflected KWhrs that day. The array looks fine.
My only concern since, has been maybe having compromised the frame/glass
interface/seal in some way that may not show any visual impact, yet.
Though it was a different scenario in that I was squirting hot water from the
ground below the array resulting in a pretty diffuse spray with virtually no
force to it by the time it reached it's target.</font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<div><font face="Times New Roman" size="3">
Jeez, the things we do for a winter off-grid KW.</font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<div><font face="Times New Roman" size="3">Bill</font></div>
<div><font face="Times New Roman" size="3">Feather River Solar
Electric</font></div>
<div><font face="Times New Roman" size="3"></font> </div>
<blockquote style="PADDING-RIGHT:0px;PADDING-LEFT:5px;MARGIN-LEFT:5px;BORDER-LEFT:#000000 2px solid;MARGIN-RIGHT:0px"><div class="im">
<div style="FONT:10pt arial">----- Original Message ----- </div>
<div style="BACKGROUND:#e4e4e4;FONT:10pt arial"><b>From:</b>
<a title="benn@daystarsolar.ca" href="mailto:benn@daystarsolar.ca" target="_blank">Benn Kilburn
- DayStar Renewable Energy</a> </div>
</div><div class="im"><div style="FONT:10pt arial"><b>To:</b> <a title="re-wrenches@lists.re-wrenches.org" href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches</a> </div>
<div style="FONT:10pt arial"><b>Sent:</b> Thursday, April 18, 2013 10:05
AM</div>
<div style="FONT:10pt arial"><b>Subject:</b> Re: [RE-wrenches] Cleaning
Modules</div>
<div><br></div>
<div>
<div>
<div>Corey,</div>
<div>If rain water isn't doing good enough, which it usually does depending on
angle and other factors…..</div>
<div><br></div>
<div>-pick up a window washing squeegee (like at a gas station) that you can
add a longer, maybe telescopic handle. That works great.</div>
<div>-Just use water, it works fine. There is no need for additional
chemicals or cleaners. If bird crap or dirt is particularly stubborn
just wet it, scrub it, wet it again and let it soak a few minutes, then it
should wipe right off. Keep in mind most module mfgrs recommend nothing
more than a mild detergent added to water (read the specific module
instructions). </div>
<div>-Be wary of temp differences between water and module glass. Cold
water on hot glass can cause the glass to crack. Best to wash in the
morning before the glass heats up.</div>
<div><br></div>
<div>I've seen a few module washing products (automatic sprayers) advertised,
but have no first hand experience with any.</div>
<div><br></div>
<div>Good luck,</div>
<div>benn</div>
<div><br></div></div></div></div><span><div class="im">
<div style="padding-left:0in;padding-right:0in;border-right:medium none;padding-top:3pt;text-align:left;font-size:11pt;border-bottom:medium none;font-family:Calibri;border-top:#b5c4df 1pt solid;padding-bottom:0in;border-left:medium none">
<span style="FONT-WEIGHT:bold">From: </span>Corey Shalanski <<a href="mailto:cshalanski@joule-energy.com" target="_blank">cshalanski@joule-energy.com</a>><br><span style="FONT-WEIGHT:bold">Reply-To: </span>RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>
<span style="FONT-WEIGHT:bold">Date: </span>Wednesday, April 17, 2013 7:20
PM<br><span style="FONT-WEIGHT:bold">To: </span>RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br><span style="FONT-WEIGHT:bold">Subject: </span>[RE-wrenches] Cleaning
Modules<br></div>
<div><br></div>
</div><blockquote style="PADDING-RIGHT:0px;PADDING-LEFT:5px;PADDING-BOTTOM:0px;MARGIN:0px 0px 0px 5px;BORDER-LEFT:#b5c4df 5px solid;PADDING-TOP:0px"><div class="im">Greetings
Wrenches,
<div><br></div>
<div>I am wondering if anyone can offer tried-and-true tips for cleaning
modules: tools, materials, methods?</div>
<div><br></div>
<div>--</div>
<div>Corey Shalanski</div>
<div><a href="http://joule-energy.com/" target="_blank">Joule Energy</a></div>
<div>New Orleans, LA</div></div>_______________________________________________
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<br></blockquote></div><br><br clear="all"><br>-- <br><div dir="ltr">Bill Hoffer <br>P.O. Box 1823<br>White Salmon, WA 98672<br><a href="mailto:bhoffer@sunergyengineeringservices.com" target="_blank">sunengser@gmail.com</a><br>
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