[RE-wrenches] Dealing with snow

Chris Daum chris at OasisMontana.com
Fri Aug 14 19:50:52 PDT 2009


Hi Matt:

I always figured that 'Solar Maid' stuff must be similar (but I have not
thoroughly investigated their 'hype'!).  Since Rain-X doesn't seem to
dissolve the rubber/silicon around car windows, it oughta work for modules.
But, I have only used it on my small array.  I live near a dusty road, and
around folks (including myself) with wood heat, so soot and ash in winter is
a factor too.

--Chris @ the Oasis Montana 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Friday, August 14, 2009 7:36 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Dealing with snow

Caution "recommending" RainX. Module manufacturers in the past have said it
"might invalidate warranty". Their stated reason: Product has not been
tested for use with the sealants on modules. May be incompatible or cause
degradation. 

Use at your own risk. 

My own non-scientific use of RainX on modules over 2 year period showed
noticeable performance improvement over "untreated" modules in the summer.
Soiling was significantly reduced on the treated modules. Treated modules 1x
per year. Late April. Sacramento. Tested 4 treated systems. 2 thin-film
frameless laminate sites and two framed poly sites.

I like it. Would use it on my own system (if the landlord would let us
install one!)

Matt Lafferty

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Chris Daum
Sent: Friday, August 14, 2009 2:08 PM
To: 'RE-wrenches'
Subject: [RE-wrenches] Dealing with snow

Here in western Montana, I have my modules mounted at about a 45 degree
angle (but they're hanging off of a south-facing soffit -- so there no roof
accumulation to worry about); annually I put that 'Rain-X' stuff on, and it
really helps keep the snow from sticking unless it's super icy.  A little
sun causes the snow to slip off rather easily.  

Chris Daum
Oasis Montana Inc. 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Darryl
Thayer
Sent: Friday, August 14, 2009 3:01 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Dealing with snow

Hi I have a large array that I mounted at 45 deg.  it mostly clears itself.
however two years ago it held ice and snow for 3 Weeks.  I wanted to try BoB
Gudgel's snow melt routine, but he was to busy to give me details, then the
snow melted.  I have never had problems with  the snow build up behind
modules.  But in Minnesota we have 40 to 50 lb snow load, and some places in
Main or Vermont have 100 or more.
Darryl  

--- On Fri, 8/14/09, penobscotsolar at midmaine.com
<penobscotsolar at midmaine.com> wrote:

> From: penobscotsolar at midmaine.com <penobscotsolar at midmaine.com>
> Subject: Re: [RE-wrenches] Dealing with snow
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Friday, August 14, 2009, 3:48 PM Hi August,
>    Here in Maine we get pretty decent
> amounts of snow. There isn't any
> foolproof way to keep your panels clear without doing it manually 
> because we sometimes get sticky, half ice, half snow type of 
> precipitation, but here's some of the things we do.
> >
> >
> >
> > 1. Do you typically mount arrays flush to the roof? If
> so, I'm assuming
> > that roof pitches are generally designed to handle the
> various snow load
> > and snow-shed scenarios depending on how much snow the
> area sees?
> 
>   We do typically flush mount, providing the roof pitch is the typical
> 10-12 pitch. If it is less we have used tilt up racks, but that 
> seriously cuts down the available usable array sq.footage.
> The roofs
> here are built to handle snow loads exceeding what we would normally 
> get, but you will still often see people on less than 10 pitched roofs 
> cleaning them off in the middle of Feb.
> 
> 
> >
> > 2. Does the height off the roof matter? In other
> words, is it better to
> > mount low to the roof or higher above the roof. Does
> snow wedge under the
> > array?
> 
> We have always mounted as close to the peak as possible. I have seen 
> arrays, not installed by my company, in which the snow has built up 
> over time on the top of an array mounted too far below the roof 
> line/peak. The snow melts and refreezes and quickly becomes a 
> liability to the effectiveness of the array, at least. We have moved 
> the entire array to the top of the roof line and the clients no longer 
> had that problem. Of course, for customers that rely on a roof rake to 
> remove snow from their array, moving the panels to the highest point 
> on the roof essentially removes that option.
> 
> 
> >
> > 3. Are there products out there designed to help shed
> snow?
> 
>    We have used Rain-X. It does seem to help. Occasional 
> re-application is necessary. Beside that, I haven't used any other 
> option.
> Maybe a solar
> powered electric heater :-) would work?
> 
> 
>    With pole or frame mounts that are
> adjustable we tend to tilt them up
> to 80 or 85 degrees to facilitate snow shedding.
> >
> 
>    I'm sure you'll hear a lot more from other NE wrenches, amongst, 
> geographically, others.
> 
> Daryl DeJoy
> NABCEP Certified PV installer
> Penobscot Solar Design
> 

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