From: Joel Davidson <[EMAIL PROTECTED]>
Subject: Re: [RE-wrenches] ice accumulation
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>
Date: Sunday, August 17, 2008, 11:55 AM
Greetings from ice-free southern California,
Interesting string. I have only heard of 2 ways to deal
with ice and snow on
PV arrays: manual removal and waiting for the ice to melt.
I think that sending current backwards through solar
modules probably voids
the warranty.
I had a Bertoia custom-made wind generator with three 8-ft
blades when I
lived in the Ozarks. During a windless night, ice
accumulated on the
downward pointing blade and on the manual brake. In the
morning the wind
started and I was awakened by the sound of the
out-of-balance blades.
Wrestling and tying down the icy blades was the
next-to-last time that I
climbed a wingcharger tower. The last time was to remove
that wind machine
and switch to PV. Nevertheless, wind machines are used in
icy locations.
See
http://farm3.static.flickr.com/2114/2152962376_2091c3d7da_o.jpg
and http://www.yara.ca/rhjbbwg.jpg
and
http://www.puddingbowl.org/iceblog/archives/108-0850_IMG-thumb.JPG
and
http://cache.daylife.com/imageserve/0dETgVrbG7cnz/610x.jpg
and http://simonc.f2o.org/south/images/wind_generator.jpg
and
http://www.bobzook.com/pix/Loading%20stuff%20ontop%20of%20the%20Ice%20Core%20frezer-%20next%20in%20line%20is%20the%20bunk%20house%20then%20the%20kitchen.jpg
and http://the.earth.li/~alex/halley/img/DSC_8611.JPG
Happy Summertime,
Joel Davidson
see nearby ice-free solar powered ferris wheel at
http://www.californiasolarcenter.org/photovoltaics_photogallery.html
----- Original Message -----
From: "roger dixon" <[EMAIL PROTECTED]>
To: "'RE-wrenches'"
<re-wrenches@lists.re-wrenches.org>
Sent: Sunday, August 17, 2008 8:02 AM
Subject: Re: [RE-wrenches] ice accumulation
> Happy to help Bill. When it comes to solar
installations I am equally
> inexperienced, but know enough to be dangerous....
>
> Too bad about the high profile wind turbines in St.
Louis. In my own
> opinion, there is nothing worse than a turbine that is
inappropriately
> sited
> and therefore doesn't work. Too much money has
been spent by a well
> intended client with disappointing results and folks
will drive by and
> say,
> "Ah, wind electric. Look, that doesn't
work." A black eye all around due
> to an inappropriate application of the technology.
The analogy I usually
> use is, "If you put a solar system in your
basement, would you expect it
> to
> work? Of course not. It needs to be in the
sun." The same goes for wind
> turbines. Too many people do not understand they need
to be properly
> sited
> in a good wind resource, not a breeze. Siting them is
a bit more
> complicated than siting for PV.
>
> Best regards,
>
> Roger Dixon
> Certified Wind Site Assessor
> Skylands Renewable Energy, LLC
> 908.337.2057
> [EMAIL PROTECTED]
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
Behalf Of Bill
> Loesch
> Sent: Sunday, August 17, 2008 10:41 AM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] ice accumulation
>
>
> Hi Roger, It looks like you and I are the only early
risers this morning.
> You are 100% correct, I have very limited exposure to
good wind
> applications. There are at least couple of high
profile installations here
> in Saint Louis that are textbook examples of how not
to do it. And to add
> insult to injury, LEED awarded a platinum rating to
one of these building
> based (at least in part) on the points this very
visible but almost
> ineffective wind application provided.
>
> My inappropriately applied experience regarding rotors
stems from the
> rotor
> being powered from the hub rather than extracting
power from the
> airstream.
> Two different situations that I will not knowingly
confuse in the future.
> Thanks for the time and effort in explaining the error
of my ways.
>
> This leads to another issue with the new division of
the wrench list into
> solar and wind divisions. Unless someone is properly
versed in both those
> technologies, and accordingly subscribes to both those
lists, there might
> not be the very interface we are having now and the
opportunity to correct
> some "common misconceptions". Of course you
wind guys won't have to wade
> through the foibles of solar electric much less solar
thermal.
>
> Best,
>
> Bill Loesch
> Solar 1 - Saint Louis Solar
> 314 631 1094
>
> ----- Original Message -----
> From: "roger dixon"
<[EMAIL PROTECTED]>
> To: "'RE-wrenches'"
<re-wrenches@lists.re-wrenches.org>;
> <[EMAIL PROTECTED]>
> Sent: Sunday, August 17, 2008 7:44 AM
> Subject: Re: [RE-wrenches] ice accumulation
>
>
>> Hi Bill. I have to take issue with your comment,
"Certainly don't want
>> to
>> lose that shedding blade into the solar
array". Although you are in the
> RE
>> business, I have to admit, that sounds like a
NIMBY comment to me. I
>> surmise from your "Solar 1-St. Louis
Solar" sign off that you are a solar
>> guy, not a wind guy.
>>
>> Let me help you out here. What happens to a wind
turbine rotor assembly
>> when it starts to ice up? It loses its airfoil.
There is less flow
>> captured across the rotors due to the ice buildup
and the rotors will
>> slow
>> down. As the ice continues to build up, the
rotors continue to slow
>> down.
>> Eventually, and sooner than later, they will stop
rotating. What is it
> that
>> is going to shed and throw a rotor any distance?
These are two different
>> concepts anyway. Rotors very rarely get thrown
and I would submit the
> ones
>> that end up disengaged do so because of a lack of
proper maintenance over
>> time. Back to "ice shedding". Since we
now understand that as ice
>> builds
>> up rotors will slow down to the point of stopping,
what happens next?
>> Whenever it gets warm enough to melt the ice it
will drop straight down
>> as
>> it disengages from the rotor. Due to gravity the
heavier rotors will
> swing
>> toward the bottom and the lightest rotor will
swing toward the top.
>> Until
>> all the ice drops off those rotors the turbine it
will not operate.
>>
>> I'm not sure this is a wind turbine
application but only because it
> appears
>> from the pictures that once the ice arrives it may
take awhile to melt.
>> Will it melt any faster off the rotors than the PV
panels? Probably not,
> so
>> I am not sure a wind turbine will help resolve the
problem. However,
>> that
>> stems from the nature of the weather, not
anticipated damage to the
>> surrounding area due to flying ice, arcing rotors,
broken equipment, etc.
>>
>> Dogs shed, not wind turbines :-)
>>
>>
>> Roger Dixon
>> Certified Wind Site Assessor
>> Skylands Renewable Energy, LLC
>> 908.337.2057
>> [EMAIL PROTECTED]
>>
>> -----Original Message-----
>> From: [EMAIL PROTECTED]
>> [mailto:[EMAIL PROTECTED]
On Behalf Of Bill
> Loesch
>> Sent: Sunday, August 17, 2008 7:24 AM
>> To: [EMAIL PROTECTED]; RE-wrenches
>> Subject: Re: [RE-wrenches] ice accumulation
>>
>>
>> Hi Darryl, Mark, Ron, et al,
>>
>> Those are some terrific and inspiring photos. If
this is not an
> application
>> for RE, we might all go home.
>>
>> Special thanks to Mark for the good html
sleuthing. Had I seen the photo
>> I
>> would have never suggested to mount fluid
containers, Dole valves (and
> more
>> stuff) on the top of the rack.
>>
>> For the ice to accumulate as shown I am assuming
there must be some
>> really
>> strong winds. More problems with adding wind
machines than they solve?
>> Certainly don't want to loose that shedding
blade into the solar array.
>>
>> Here is another carry over from the transport
category aircraft world -
> add
>> a shaker to the mount / module. Actuated by
whatever you deem appropriate
> to
>> sense the ice accumulation. The shaker is most
often a motor with a non
>> symmetric weight on its shaft. Not exactly high
tech. Hopefully less
> energy
>> intensive than the "clean" backflow
heating.
>>
>> Again, my apologies for opening my mouth before I
knew the scope of your
>> situation. Absolutely great photos!
>>
>> Bill Loesch
>> Solar 1 - Saint Louis Solar
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Darryl Thayer"
<[EMAIL PROTECTED]>
>> To: "RE-wrenches"
<re-wrenches@lists.re-wrenches.org>
>> Sent: Friday, August 15, 2008 8:24 PM
>> Subject: Re: [RE-wrenches] ice accumulation
>>
>>
>> > Hi all
>> > This is for the far out ideas. Most cooling
and icing occurs on
>> windshields and not on side windows, due to
radiation to the night sky.
>> What if a set of tempered glass were above the
modules, such that the sun
>> would pass underneath in the winter, and pass
through in the summer. The
>> glass would serve as a radition sheild.
>> >
>> > Darryl
>> >
>> >
>> > --- On Thu, 8/14/08, Bill Loesch
<[EMAIL PROTECTED]> wrote:
>> >
>> > > From: Bill Loesch
<[EMAIL PROTECTED]>
>> > > Subject: Re: [RE-wrenches] ice
accumulation
>> > > To: "RE-wrenches"
<re-wrenches@lists.re-wrenches.org>
>> > > Date: Thursday, August 14, 2008, 9:39 PM
>> > > Hi Ron,
>> > >
>> > > While you might put this into the same
category as the
>> > > RainX; I would
>> > > consider using some type of glycol mix
perhaps delivered by
>> > > a Dole style
>> > > (temperature sensing) valve. Glycol is
what the transport
>> > > aircraft community
>> > > uses before launching an aircraft into
current ice
>> > > conditions. The Dole
>> > > style valve only dispenses the gravity
fed glycol when near
>> > > freezing
>> > > conditions exist.
>> > >
>> > > Bill Loesch
>> > > Solar 1 - Saint Louis Solar
>> > >
>> > > ----- Original Message -----
>> > > From: "Ron Young"
>> > > <[EMAIL PROTECTED]>
>> > > To: "RE-wrenches"
>> > >
<re-wrenches@lists.re-wrenches.org>
>> > > Sent: Thursday, August 14, 2008 7:12 PM
>> > > Subject: [RE-wrenches] ice accumulation
>> > >
>> > >
>> > > > Hi Wrenches,
>> > > >
>> > > > I know this is a nice cool subject
for these
>> > > (hopefully) sun filled
>> > > > days. I am working on a telecom
system that has some
>> > > issues with ice
>> > > > accumulation on the panels that
essentially shut the
>> > > system down mid
>> > > > winter. Wondering if anyone has
suggestions to remedy
>> > > the ice
>> > > > buildup. It's an extreme
mountaintop environment
>> > > with very high winds
>> > > > at times and the ice cakes up to
2" - 3" on
>> > > surfaces. There are some
>> > > > pics here:
www.solareagle/temp/ice.html
>> > > >
>> > > > Access to the site in winter is
totally out of the
>> > > question so we are
>> > > > hoping to find some ideas that
might prevent or reduce
>> > > the ice
>> > > > accumulation. When the ice shuts
the panels down the
>> > > communications
>> > > > go down.
>> > > >
>> > > > Someone suggested a slippery spray
like RainX might
>> > > help to prevent
>> > > > accumulation but I think it would
quickly be washed
>> > > off/worn out and
>> > > > I don't know the uv issues that
might reduce power
>> > > output.
>> > > >
>> > > >
>> > > > Ron
>> > > > earthRight Solar
>> > > >
_______________________________________________
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