[RE-wrenches] ice accumulation

Sun Aug 17 05:44:50 PDT 2008

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