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 <[EMAIL PROTECTED]> wrote: > From: Joel Davidson <[EMAIL PROTECTED]> > Subject: Re: [RE-wrenches] ice accumulation > To: "RE-wrenches" <[email protected]> > 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'" > <[email protected]> > 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'" > <[email protected]>; > > <[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" > <[email protected]> > >> 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" > <[email protected]> > >> > > 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" > >> > > > <[email protected]> > >> > > 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 > >> > > > > >> > > > [email protected] > >> > > > > >> > > > > >> > > > 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 > >> > > > >> > > [email protected] > >> > > > >> > > > 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 > >> > > >> > [email protected] > >> > > >> > > 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 > >> > >> [email protected] > >> > >> > 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 > >> > >> [email protected] > >> > >> > 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 > > > > [email protected] > > > > > 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 > > > > [email protected] > > > > > 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 > > [email protected] > > 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 [email protected] 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
