Wind Turbine De-Icing.

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barkingmad
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Wind Turbine De-Icing.

#1 Post by barkingmad » Mon Dec 02, 2019 2:17 pm

December UK and freezing fog with a breeze is forecast for 03/12.

Does anyone know how the wind turbine ‘wings’ cope with icing conditions or do the assemblies have imbalance detectors which would cause auto-shutdown if vibes are excessive due asymmetric icing or structural failure?

I’ve also noticed strakes and winglets on these blades as I struggle past them on my ancient bike atop a local hill. (Idiot!)

Doubtless they accrete ice in freezing fog/low cloud conditions with breeze and then there may be some mechanical shedding of ice, a danger which has presumably been assessed as negligible to passing road users or farm workers.

Also rather strange that above certain wind velocities they have to be shut down. I would have thought that some element of partial “feathering”, full feathering being evident on most of them when they’re stationary, would prevent too much energy being absorbed by the generators and exceeding the specified output rating. I have wondered if it’s an orographic turbulence factor which might cause damage to the rotating assembly. :-\

Yes, I know, I really must get out more, but that’s where the query first swam into my idle brain as the CO2 built in the leg muscles! !

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Re: Wind Turbine De-Icing.

#2 Post by ribrash » Mon Dec 02, 2019 3:17 pm

My friends son works on the wind farms out in Liverpool Bay.They have teams of technicians who are dropped off each day to carry out maintainance etc. My mates son is part of an absailing team that checks the blades for damage,particularly lightening strikes.

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Re: Wind Turbine De-Icing.

#3 Post by Pontius Navigator » Mon Dec 02, 2019 8:54 pm

I have certainly heard of ice being flung off. Despite the length of each blade I don't think they throw very far.

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Re: Wind Turbine De-Icing.

#4 Post by Pontius Navigator » Mon Dec 02, 2019 8:58 pm

Answers here;

https://www.windpowerengineering.com/cr ... ne-blades/

Seems ice can get thrown a third of a mile.

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Re: Wind Turbine De-Icing.

#5 Post by Smeagol » Wed Dec 04, 2019 11:20 pm

barkingmad wrote:
Mon Dec 02, 2019 2:17 pm
December UK and freezing fog with a breeze is forecast for 03/12.

Does anyone know how the wind turbine ‘wings’ cope with icing conditions or do the assemblies have imbalance detectors which would cause auto-shutdown if vibes are excessive due asymmetric icing or structural failure?

I’ve also noticed strakes and winglets on these blades as I struggle past them on my ancient bike atop a local hill. (Idiot!)

Doubtless they accrete ice in freezing fog/low cloud conditions with breeze and then there may be some mechanical shedding of ice, a danger which has presumably been assessed as negligible to passing road users or farm workers.

Also rather strange that above certain wind velocities they have to be shut down. I would have thought that some element of partial “feathering”, full feathering being evident on most of them when they’re stationary, would prevent too much energy being absorbed by the generators and exceeding the specified output rating. I have wondered if it’s an orographic turbulence factor which might cause damage to the rotating assembly. :-\

Yes, I know, I really must get out more, but that’s where the query first swam into my idle brain as the CO2 built in the leg muscles! !
I have been involved in constructing wind farms for the last 15 years, but all of them offshore so on the last point ,'orographic turbulence', has never been a factor. I am not an expert in WTG design or maintenance, project management of the overall construction activities was my role.

Regarding icing, I am not aware of it being a specific problem requiring specialist monitoring to prevent imbalance issues being a problem. The blades of modern WTGs are VERY large and pretty heavy so ice formation may not make a sufficient difference to become problematical. I'm guessing here but will ask an expert and give some feedback if anyone is interested.

As for shutting down in high wind velocities, this is universal, with blades being gradually feathered as velocities increase to prevent overloading of the structure. From memory on earlier WTGs, power output ramps up from about 4m/s (below that nothing much is produced) up to when maximum power is generated at around 13m/s up to 25m/s after which the machine is shutdown. This may be different now as my knowledge was on machines about 10 years ago.
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Re: Wind Turbine De-Icing.

#6 Post by G~Man » Thu Dec 05, 2019 12:30 am

2vwe38.jpg
2vwe38.jpg (73.11 KiB) Viewed 7353 times
B-) Life may not be the party you hoped for, but while you're here, you may as well dance. B-)

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Re: Wind Turbine De-Icing.

#7 Post by llondel » Thu Dec 05, 2019 12:53 am

"wind turbine overspeed" is an interesting search term on YouTube.

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Re: Wind Turbine De-Icing.

#8 Post by Rwy in Sight » Thu Dec 05, 2019 6:25 am

Smeagol, we are looking forward to hear from your expert. To all why they don't put de-icing boots on the blades? And why they don't try to adjust the feathering to extend the wind speeds they operate?

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Re: Wind Turbine De-Icing.

#9 Post by G-CPTN » Thu Dec 05, 2019 7:15 am

G~Man wrote:
Thu Dec 05, 2019 12:30 am
2vwe38.jpg
Yes, indeed!

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Re: Wind Turbine De-Icing.

#10 Post by llondel » Thu Dec 05, 2019 5:24 pm

On a similar note, I'm wondering whether I need to get on a ladder and clean the solar panels on the roof. Can't quite justify using a helicopter to do it.

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Re: Wind Turbine De-Icing.

#11 Post by Rwy in Sight » Thu Dec 05, 2019 8:11 pm

I think there is the issue of distance. Most roofs are much lower than the blades.

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Re: Wind Turbine De-Icing.

#12 Post by barkingmad » Tue Dec 10, 2019 5:44 pm

Thanks to all so far for trying to answer my OP. Today Tue 10th Dec as the northern UK is blasted by gale force winds and rain, toppling HGVs on main roads and causing transport chaos, I managed to drive south along the (scenic sometimes) A68 from Edinburgh and past the Cheviots and observe numerous land sited wind turbines and apart from the odd one 'feathered', none had any evidence of 'coarse pitch' to reduce the energy input into blades and generators.

But over a year ago my local 4-turbine wind farm lost one for nearly a year with a shredded blade which resulted in major works to restore the assembly to working condition. Strangely this one turbine is sited at a lower altitude and behind it's 3 mates on the ridge and downwind of potential wind rotors coming off the ridge in gale winds. So that's what led me to ask about orographic turbulence possibly causing problems with asymmetric and transient loading of the blades.

I presume the land site owners carry insurance against ice shedding into the windscreen of the orphanage bus passing by on the adjacent public highway etc etc?

Re PV panels mine have been up for 8 years, never cleaned, the Northeast weather takes care of that.

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Re: Wind Turbine De-Icing.

#13 Post by barkingmad » Sat Feb 08, 2020 4:55 pm

What happens to all the old wind turbines? https://www.bbc.co.uk/news/business-51325101

Well hopefully that answers that question?

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Re: Wind Turbine De-Icing.

#14 Post by barkingmad » Thu Aug 27, 2020 8:48 am

“Though the mills of God grind slowly...”

I recall propellor aircraft going through the same evolution back mid-last century so it seems odd we get this far before the same possible solution to bird strikes is now being trialled with the wind turbine fraternity;

Black turbine blade can cut bird deaths' https://www.bbc.co.uk/news/science-environment-53909825

Of course the black blade will absorb more heat on a sunny day and therefore....(insert appropriate technical problem of your choice?)

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Re: Wind Turbine De-Icing.

#15 Post by TheGreenGoblin » Thu Aug 27, 2020 9:11 am

barkingmad wrote:
Thu Aug 27, 2020 8:48 am
“Though the mills of God grind slowly...”

Of course the black blade will absorb more heat on a sunny day and therefore....(insert appropriate technical problem of your choice?)
Will delaminate at high temperatures causing the turbine to fail. I made that up. I don't know if it is really a problem.

I can find no evidence to back up my wild claim about black turbine blade debonding or delamination!

https://www.windpowerengineering.com/wh ... d%20Energy.
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Re: Wind Turbine De-Icing.

#16 Post by Boac » Thu Aug 27, 2020 9:23 am

I'm a bit concerned about 'motion smear'.

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Re: Wind Turbine De-Icing.

#17 Post by TheGreenGoblin » Thu Aug 27, 2020 9:26 am

But look at this serendipitous discovery...
Spies and soldiers might soon be able to go behind enemy lines using a parachute or glider made from a polymer that vanishes on exposure to sunlight.

“This started off with building small sensors for the government — microphones, cameras, things that detect metal,” says Paul Kohl at the Georgia Institute of Technology, who presented the work at a meeting of the American Chemical Society in California this week.

The idea was that these sensors could be spread across a battlefield, say, and used to collect information for the army. “But you don’t want anyone to discover it and take it apart and see how it works,” says Kohl.

That’s why he and his team wanted to invent a self-destructing material. They began with polymers that have a low ceiling temperature, which is the point at which the key bonds holding the substance together begin to break.

They based their polymer on a chemical called an aldehyde and mixed in other chemical additives that can either make it rigid for use in a glider or sensor, or flexible to make a fabric for a parachute.

Sunlight or artificial light can trigger the material to go poof. Or, in true spy style, a small light emitting diode can be placed inside a device to trigger the self-destruct process on demand. All that’s left behind is a residue and a faint smell, which Kohl says are from the additives that control the rigidity of the material.


Lots of polymers break down slowly when they reach this temperature because many bonds have to be broken. But Kohl designed his material so that as soon as one bond breaks the whole thing rapidly unzips.
Read more: https://www.newscientist.com/article/22 ... z6WJEQVFWN
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Re: Wind Turbine De-Icing.

#18 Post by barkingmad » Thu Aug 27, 2020 9:29 am

Nice one, good try! But I was thinking more about different blade temperatures meaning differential expansion leading to an out of balance condition.

And presumably if one blade receives a retrospective mod consisting of another coat of black paint, does that not immediately introduce an imbalance, therefore all blades would need a repaint if done post-commissioning?

It’s the sort of rubbish which occupies what’s left of my brain as I pedal into wind past my local wind farm wondering WTF am I doing there in the first instance!

But I couldn’t help noticing the newest assembly which replaced the shredded blade victim has tiny winglets on the blade tips and appears to revolve at 10 rpm compared to the 12 rpm of the older turbines in the same brisk breeze.

For parents, motion-smear is that complicated manoeuvre performed attempting to clear the snot from under the child’s nostrils whilst balancing shopping and trying to get the car doors open whilst the child is trying to escape. Simples! =))

Edited to add: “But Kohl designed his material so that as soon as one bond breaks the whole thing rapidly unzips.“

Barbara Broccoli might be concerned at that news though the films were never the same after Ssshean Connery ceased starring!

Meanwhile, back to watching paint drying...

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Re: Wind Turbine De-Icing.

#19 Post by Boac » Thu Aug 27, 2020 9:30 am

"a parachute or glider made from a polymer that vanishes on exposure to sunlight." Hey - they have invented a snowflake machine!

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Re: Wind Turbine De-Icing.

#20 Post by TheGreenGoblin » Thu Aug 27, 2020 9:39 am

barkingmad wrote:
Thu Aug 27, 2020 9:29 am
Nice one, good try! But I was thinking more about different blade temperatures meaning differential expansion leading to an out of balance condition.
And presumably if one blade receives a retrospective mod consisting of another coat of black paint, does that not immediately introduce an imbalance, therefore all blades would need a repaint if done post-commissioning?

It’s the sort of rubbish which occupies what’s left of my brain as I pedal into wind past my local wind farm wondering WTF am I doing there in the first instance!
Meanwhile, back to watching paint drying...
I salute you as a kindred spirit! =))

Such mental detritus is carried down by the glacier that masquerades as my mind every day.
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