[RE-wrenches] ice accumulation

Sun Aug 17 17:34:16 PDT 2008

Ice falling from antennas is a real problem. I had a repeat customer who 
replaced 6 to 12 broken solar modules every year in an array next to an 
antenna located at 9600 feet in the San Gorgonio mountains in California. In 
addition to the modules and labor, the station owner had to pay for a half 
day helicopter travel. The same array was originally installed on a 
piston-driven tracker that kept coming apart in the wind. The tracker 
problem was solved by adding more modules and locking the array to face 
south. After several years, the owner eventually moved the array.

Another customer with a PV powered radio repeater on the western slope of 
the Cascade mountains had a problem with the first snowfall in September 
staying on the array for 3 weeks. The first snow usually started as freezing 
rain that coated the array and then snow. The solution was to add enough 
battery storage for 3 weeks of autonomy.

No rocket science or complicated gadgets are needed. Just good system design 
avoids most problems or deals with most conditions.

The nature of a problem is that it has solutions. If there are no solutions, 
then it is a condition, not a problem.

Joel Davidson

----- Original Message ----- 
From: "Darryl Thayer" <daryl_solar at yahoo.com>
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Sent: Sunday, August 17, 2008 10:19 AM
Subject: Re: [RE-wrenches] ice accumulation

> Thanks for all the Icing information.  In minnesota a person (at least 
> one) was killed by ice falling from roof.  Further there have been several 
> posts (not here) on Ice damage from ice sheading from turbine blades.  I 
> always try to warn turbine owners of potentical Ice sheading and damage. 
> I remember a fellow at a university who presented a paper on Ice sheading 
> from turbine blades.\  Sorry I do not remember more.
> Darryl
>
>
> --- On Sun, 8/17/08, Joel Davidson <joel.davidson at sbcglobal.net> wrote:
>
>> From: Joel Davidson <joel.davidson at sbcglobal.net>
>> Subject: Re: [RE-wrenches] ice accumulation
>> To: "RE-wrenches" <re-wrenches at 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" <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
>> >
>>
>> _______________________________________________
>> 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
> 