[RE-wrenches] Cleaning Modules

Bill Hoffer sunengser at gmail.com
Fri Apr 19 09:16:13 PDT 2013


Bill

Kids do not try this one at home!  Which of course will make the kids want
to do it even more.

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!

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.....

Bill




On Thu, Apr 18, 2013 at 10:23 PM, frenergy <frenergy at psln.com> wrote:

> **
> benn and interested others,
>
>         Just a side note due to benn's comment about cold water on a hot
> panel possibly resulting in cracked glass.
>
>         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??
>
>         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.
>
>         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.
>
>         Jeez, the things we do for a winter off-grid KW.
>
> Bill
> Feather River Solar Electric
>
>
> ----- Original Message -----
> *From:* Benn Kilburn - DayStar Renewable Energy <benn at daystarsolar.ca>
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Sent:* Thursday, April 18, 2013 10:05 AM
> *Subject:* Re: [RE-wrenches] Cleaning Modules
>
>  Corey,
> If rain water isn't doing good enough, which it usually does depending on
> angle and other factors…..
>
> -pick up a window washing squeegee (like at a gas station) that you can
> add a longer, maybe telescopic handle.  That works great.
> -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).
> -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.
>
> I've seen a few module washing products (automatic sprayers) advertised,
> but have no first hand experience with any.
>
> Good luck,
> benn
>
> From: Corey Shalanski <cshalanski at joule-energy.com>
> Reply-To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Date: Wednesday, April 17, 2013 7:20 PM
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Subject: [RE-wrenches] Cleaning Modules
>
> Greetings Wrenches,
>
> I am wondering if anyone can offer tried-and-true tips for cleaning
> modules: tools, materials, methods?
>
> --
> Corey Shalanski
> Joule Energy <http://joule-energy.com/>
> New Orleans, LA
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-- 
Bill Hoffer
P.O. Box 1823
White Salmon, WA 98672
sunengser at gmail.com <bhoffer at sunergyengineeringservices.com>
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