[RE-wrenches] ice accumulation

Sun Aug 17 09:55:16 PDT 2008

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" <roger.dixon at att.net>
To: "'RE-wrenches'" <re-wrenches at 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
> roger.dixon at att.net
>
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] 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" <roger.dixon at att.net>
> To: "'RE-wrenches'" <re-wrenches at lists.re-wrenches.org>;
> <daryl_solar at yahoo.com>
> 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
>> roger.dixon at att.net
>>
>> -----Original Message-----
>> From: re-wrenches-bounces at lists.re-wrenches.org
>> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bill
> Loesch
>> Sent: Sunday, August 17, 2008 7:24 AM
>> To: daryl_solar at yahoo.com; 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" <daryl_solar at yahoo.com>
>> To: "RE-wrenches" <re-wrenches at 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 <solar1online at charter.net> wrote:
>> >
>> > > From: Bill Loesch <solar1online at charter.net>
>> > > Subject: Re: [RE-wrenches] ice accumulation
>> > > To: "RE-wrenches" <re-wrenches at 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"
>> > > <solareagle at solareagle.com>
>> > > To: "RE-wrenches"
>> > > <re-wrenches at 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
>> > > > _______________________________________________
>> > > > List sponsored by Home Power magazine
>> > > >
>> > > > RE-wrenches at lists.re-wrenches.org
>> > > >
>> > > >
>> > > http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>> > > >
>> > > > List rules & etiquette:
>> > > > http://www.re-wrenches.org/etiquette.htm
>> > > >
>> > > > Check out participant bios:
>> > > > www.members.re-wrenches.org
>> > > >
>> > > >
>> > > >
>> > > > -- 
>> > > > No virus found in this incoming message.
>> > > > Checked by AVG.
>> > > > Version: 7.5.524 / Virus Database: 270.6.3/1611 -
>> > > Release Date: 8/14/2008
>> > > 6:20 AM
>> > > >
>> > > >
>> > >
>> > > _______________________________________________
>> > > List sponsored by Home Power magazine
>> > >
>> > > RE-wrenches at lists.re-wrenches.org
>> > >
>> > > http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>> > >
>> > > List rules & etiquette:
>> > > http://www.re-wrenches.org/etiquette.htm
>> > >
>> > > Check out participant bios:
>> > > www.members.re-wrenches.org
>> >
>> >
>> >
>> > _______________________________________________
>> > List sponsored by Home Power magazine
>> >
>> > RE-wrenches at lists.re-wrenches.org
>> >
>> > http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>> >
>> > List rules & etiquette:
>> > http://www.re-wrenches.org/etiquette.htm
>> >
>> > Check out participant bios:
>> > www.members.re-wrenches.org
>> >
>> >
>> >
>> > -- 
>> > No virus found in this incoming message.
>> > Checked by AVG.
>> > Version: 7.5.524 / Virus Database: 270.6.3/1613 - Release Date:
> 8/15/2008
>> 5:58 AM
>> >
>> >
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> RE-wrenches at lists.re-wrenches.org
>>
>> http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm
>>
>> Check out participant bios:
>> www.members.re-wrenches.org
>>
>> No virus found in this incoming message.
>> Checked by AVG - http://www.avg.com
>> Version: 8.0.138 / Virus Database: 270.6.4/1616 - Release Date: 8/16/2008
>> 5:12 PM
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> RE-wrenches at lists.re-wrenches.org
>>
>> http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm
>>
>> Check out participant bios:
>> www.members.re-wrenches.org
>>
>>
>>
>> -- 
>> No virus found in this incoming message.
>> Checked by AVG.
>> Version: 7.5.524 / Virus Database: 270.6.4/1615 - Release Date: 8/16/2008
> 7:11 AM
>>
>>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> RE-wrenches at lists.re-wrenches.org
>
> http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com
> Version: 8.0.138 / Virus Database: 270.6.4/1616 - Release Date: 8/16/2008
> 5:12 PM
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> RE-wrenches at lists.re-wrenches.org
>
> http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
> 