[RE-wrenches] ice accumulation

[Darryl Thayer]

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
> >> > > >
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