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Good presentation on wind power systems.

Iron

Interesting... There's much more to wind power than a wind mill.
Thanks Jon, Ann, Design News and Digi-Key.

Iron

What can be used to offset variations in windspeed? some sort of storage system

Iron

How do modern windmills slow themselves down in high wind? Blade angle of attack.

Iron

How can you tell by looking at a windmill if it has a fixed axis? Use of a directional blade?

Iron

what percentage of the cross-sectional area do the blades represent? 8%?

Iron

Hello from Beaverton, Oregon. Catching up on some archived courses.

Iron

Thanks Jon and Digi-Key

Iron

electro-dynamic brakes, free spin

slowdown by changing blades configuration, electro-dynamic brakes

By the shape of blades and by the gear box under windmill body

Averaged historical data to calculate approximate capacity of windmill

I would think that the modern windmills would feather the blades to keep rotational speed from getting too high.

Gold

Thanks Jon for the informative presentation

Platinum

i think for residential purpose a comination of wind and solar enrgy harvesting can power the house through the year

Platinum

i think it can combain with other sources to form hybrid energy sources

Platinum

wind is one of the relible alternate source of energy

Platinum

Although I can't break the laws of physics,  I'll continue to do my best to bend a few now and then...

Iron

... disregard my previous question about the 3 blade geometry. I found my answer here.

http://en.wikipedia.org/wiki/Blade_element_momentum_theory

a good read.

 

Iron

Sorry, we have them here in the university.  You might consider service bureaus, unless IP is a concern.

Iron

I best get back to my day job... 

Thanks for the thoughts and comments.

 

Take care

Iron

I've been trying to convince my wife I need a 3D printer. Any suggestions Doug?

Platinum

All i have to work with is cardboard and paper clips... Lol   :-(

Iron

@78RPM  We have the printers, but not the funding for the materials :(

Iron

Yes i liked that one too but was thinking how to integrate it inot a smaller form.  somthing to perch on a pole mount.    I have a large pole avalible (wooden  telephone like pole) in my yard. I'd like ot put somehtign up there for wind. 

Iron

Hey, Joe_S and Doug Cook, maybe we could get a 3D printer and experiment with some designs.

Platinum

@Joe_S  That is the basis of the "wind sock" design in the slides.  They use a small turbine at the exit.  This is my favorite design so far.

Iron

Good to keep thinking. :)

Platinum

Turbines in a sense. yes.  If I am to assume the 59% area is the limitation, then i'd assume that woud be about the optimum surface areea to expose in the circle of th e blades to approch best harvest effecency...?

Turbines withiout the tube though.   But that does pose an intresgingvaiation as the tube would allow maniputaion of the pressures/velocities of air captured...  that too has me thinking...

Iron

@Joe_S Yes, like jet turbines and compressors.

Iron

I agree, Joe_S.  But who needs 100% efficiency when the wind is free? Just do it in the way that does not irritate your neighbors.

Platinum

I was not thinking on the grand scale of wind harvestign but more like the windmills of the old west used to pump water. Seems when applied to small home type implimentations it may be a simpler approch than the flapping vane approch of the vertical axsis type. ie. less movin parts and less noise generated.

 

Iron

On slide 19, you see the parabolic exit chamber. and parabolic entry chamber. The blades are probably in the waistline behind the sign.  The exit air has to expand.

Platinum

@Joe_S.  See the Wikipedia article on Betz's Law. There is a cartoon you can enlarge to see the concept when the first air molecule loses all its energy and the second molecule cannot get through because the blade is stopped and all the energy is sapped.  It's a cute intuitive explanation.

Platinum

@Joe_S I suspect weight and maintenance costs are the issues

Iron

Why limit the baldes to three.   can you improve cross sectional area by increasing the blade count and thus increase your harvest effiency?

 

Iron

? yes, I have one more... 

Iron

Thank you all -- Tomorrow we talk about geothermal -- Hope you will be there.  -- Jon

Iron

Thanks for all the kind words, Are there any questions I missed? If so - Please chime in now.

 

Iron

:)  Thanks on the heaven comment. Maybe I'm already there.  A very powerful WiFi link...

Iron

?? Jon, I like the idea of vertical axis because it is much easier to put up mesh and protect wildlife. Any studies on what mesh does to eddies in the wind flow that might affect efficiency?

I agree with Daniel I "Ur going to heaven for sure" :)

 

I haven;t seen any studies on mesh effects on micro eddy currents. Like the shape of the piano (pink noise curve), we humans will intuitively arrive at the optimum design by trial and error, even before we understand the math.

Iron

Thanks Jon, great presentation!

Iron

??? @jongabay and Doug Cook, Yes, that is the key -- something has to keep moving.  I something is still moving then you have not captured 100% of the kinetic energy of the wind.  The theoretical limit to efficiency is 59.3% by Betz's Law.  Jon's idea of retractable blades is a good one if they are arrayed as a front to the wind.  But if they are trapped in a tube, the very back blade will be getting very little velocity.  If we stop the wind at the back of the tube, not further air can flow. Force X Distance = 0 because of zero distance.


True, here will never be zero return force. It's kind of like phoencian blinds in the wind. When the wind blows one way, they open and present very little drag. When the wind blows the other way, they snap shut and take all the energy.

 

Iron

?? Jon, I like the idea of vertical axis because it is much easier to put up mesh and protect wildlife. Any studies on what mesh does to eddies in the wind flow that might affect efficiency?

I agree with Daniel I "Ur going to heaven for sure" :)

Platinum

??? Ur going to heaven for sure ;) ???

Iron

???too late to patent the idea... it's just now got into the public domain ... BUGGER... should hav kept my mouth shut :( ??? 

??? yup... it could be ferris type cups ... or much loger vanes. same as the verticallly oriented ones???

Interesting idea. Worth some investigating. Thanks --

 

I think that as long as the outcome is less toxins in the air and clean energy, being public domain is a good thing. Besides, by placing into the public domain in a published setting, no one can patent it. Consider it a possible gift to the world.

 

 

Iron

In northern climes (Canada/Alaska/Minnesota) you also have to feed power to wind turbines to warm and de-ice them before use -- allow for that in your budget for personal systems.

Iron

@jongabay and Doug Cook, Yes, that is the key -- something has to keep moving.  I something is still moving then you have not captured 100% of the kinetic energy of the wind.  The theoretical limit to efficiency is 59.3% by Betz's Law.  Jon's idea of retractable blades is a good one if they are arrayed as a front to the wind.  But if they are trapped in a tube, the very back blade will be getting very little velocity.  If we stop the wind at the back of the tube, not further air can flow. Force X Distance = 0 because of zero distance.

Platinum

Yes and consiering ... capitol investment is only part of the cost ... I saw a commercial wind farm with many of the windmills inoperable and after closer inspection they appeared to have been that way for quite sometime ... i presume beacuse cost and resources weren't availabel to maintain them and may not have beeen considered into projecct pre-planning ...

????Urban jungle (mounting wind mills on top of high risers) seems to be perfect for wind power generation.  I don't see that happening though.  Is it because of cost or these smaller wind turbine are just not worth doing it (ie, they can't produce enough energy to make it worth while)?  Thanks


It is possible to use wind generators on top of high rise buildings as long as they are very secure. Gusts at high altitude can dislodge pieces and fall on people below. This also puts a lot of strain on roof structures. But, it can be done, especially to keep things like emergyency lights going independantly.

 

Iron

Thw Industrial wind turbines (commercial large systems) definitely rotate into the wind -- new ones anyway.

Iron

???too late to patent the idea... it's just now got into the public domain ... BUGGER... should hav kept my mouth shut :( ??? 

??? yup... it could be ferris type cups ... or much loger vanes. same as the verticallly oriented ones???

Interesting idea. Worth some investigating. Thanks --

Iron

could u elaborate on AC over DC generation. advantages and disadvantages. thx

Iron

g'day from sydney, australia. i just want 2c my name in print :)

Iron

??? thx for ur answer... i was thinking in terms of dynamos v alternators???

 

Iron

???could u elaborate on AC over DC generation. advantages and disadvantages. thx

 

Iron

??? by using a horizontal axis but using a bucket type collector with the axis normal to the wind direction... could the difference in wind velocity due to ground drag be used. i.e the higher collectors would receive a faster wind flow than the lower ones???

Iron

But for some products which the company have gone out of buisness, repairing may be the best option.

Iron

@78RPM Yes, but this seems only to be a limitation with the 3-blade wind turbines.  For those like the vertical-axis turbines, they can move a distance in the direction of the flow.

Iron

??? ofcourse rotating them to face the wind would be impossible.... useful for fixed wind direction only???

Iron

??? yup... it could be ferris type cups ... or much loger vanes. same as the  verticallly oriented ones???

Interesting idea. Worth some investigating. Thanks --

 

Iron

??@Doug Cook, Work = Force X Distance.  If you bring the wind to a stop, capturing all the energy in that column, not further air can flow.  Thus you would have Work = Force X 0 = 0 further work until you let the air start flowing again.  See the article in Wikipedia.

 

That is true, but as long as the wind is pressing on something that is moving, there is distance so work is done. The horizontal louvers rotate and move with the force of the wind.

 

 

Iron

??? yup... it could be ferris type cups ... or much loger vanes. same as the  verticallly oriented ones???

Iron

??f you are thinking of repairing "inverters" they are considered a "throw away" wear component. At least with people I know...

Thanks - It seems so much is throw away these days. I miss when anything could be rebuilt and repaired.... Sigh.

Iron

@Doug Cook, Work = Force X Distance.  If you bring the wind to a stop, capturing all the energy in that column, not further air can flow.  Thus you would have Work = Force X 0 = 0 further work until you let the air start flowing again.  See the article in Wikipedia.

Platinum

??? by using a horizontal axis but using a bucket type collector with the axis normal to the wind direction... could the difference in wind velocity due to ground drag be used. i.e the higher collectors would receive a faster wind flow than the lower ones???


I don't know. I think I understand what you are asking. You are talking about a ferris wheel type of architecture where the difference in pressures on top and at ground level causes rotation?

Iron

Answer to question 4 -- A flywheel can be used to help normalize wind energy. A centrifical clutch could deliver burst of rotational energy until it gets spinning. Then the clutch would continue to be engaged once it reaches speed and deliver steady energy to the flywheel and wind system whenever the wind was blowing.

 

 

Iron

??? by using a horizontal axis but using a bucket type collector with the axis normal to the wind direction... could the difference in wind velocity due to ground drag be used. i.e the higher collectors would receive a faster wind flow than the lower ones???

Iron

If you are thinking of repairing "inverters" they are considered a "throw away" wear component. At least with people I know...

Iron

Answer to question 3 -- Modern windmills slow themselves down by changing the blades pitch in very high wind speeds.

Iron

Question 2 most people answered -- The use of a tail centers it in the windstream

Iron

??Urban jungle (mounting wind mills on top of high risers) seems to be perfect for wind power generation.  I don't see that happening though.  Is it because of cost or these smaller wind turbine are just not worth doing it (ie, they can't produce enough energy to make it worth while)?  Thanks

Iron

Answer to question 1 -- Typically the blades only take up around 10% of the cross sectional area on a typical 3 blade windmill.

 

Iron

" Betz's law (1919) says that no turbine can capture more than 59.3% of available kinetic wind energy. That's becuase if we captured 100% of the wind's energy we would bring the air flow to a stop which would block any further flow of air into the turbine."

 

I am not familiar with this law; but, as Jon pointed out, stopping air flow with a blunt body will induce a force from the stagnation pressure generated.

 

Iron

??@ccrider  What is that company that repairs electronics for wind generators?


I only know of a company in PA called MATRIC who makes and repairs the blade pitch controls for protecting wind turbines in high wind conditions.

 

The wind turbine manufacturer hopefully has a repair chain as well.

Iron

??Could you expound on why you prefer a vertical axis system?


Because I can put more wind turbines on a single tower. Since the tower is such a big part of the cost, it is nice to maximize the return on its investment.

 

If I can double the power by adding half more cost, I'm ahead of the game.

 

Iron

Thank you for Today's lecture Jon

Iron

People interested in "Pumped Storage" might want to amuse themselves reading this..

http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/

It's by Dr. Tom Murphy of UCSD

 

Thank you -- Water is a vital resource and when emergyency situations occur, indepenant water systems are good to have.

 

Iron

?? Is your vertical axis system self starting? I understand that some of them need a motor to get  rotating again once they stop.

 

Yes, it uses a louver system so when enough wind hits them, they close and take all the wind, but when they return, they open and slice through the wind,

 

Iron

@DaveWR, ooh, thanks. I live on very hilly ground(64 acres) and might be able to use the ideas.

Platinum

?? I like your design on slide 20. I assume you monitor angular position to activily solenoid retract the blade on the return.
I'm not sure about your comment about putting two on the same slot (I'm trying to imagine the geometry). Referring to my previous post: Betz's law (1919) says that no turbine can capture more than 59.3% of available kinetic wind energy. That's becuase if we captured 100% of the wind's energy we would bring the air flow to a stop which would block any further flow of air into the turbine.

 

Interesting notion. But even if wind flow stopped, force would still be applied to a rotating and changing surface. That force moving a medium a distance is work. It may be semantics. We would have to check with an aeronautic engineer. Thanks for the interesting poin to ponder on.

 

 

 

Iron

?? Is your vertical axis system self starting? I understand that some of them need a motor to get  rotating again once they stop.

Iron

People interested in "Pumped Storage" might want to amuse themselves reading this..

http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/

It's by Dr. Tom Murphy of UCSD

 

Tom Murphy is an associate professor of physics at the University of California, San Diego. - See more at: http://physics.ucsd.edu/do-the-math/tom-murphy-profile/#sthash.NdPH91PV.dpuf
Tom Murphy is an associate professor of physics at the University of California, San Diego. - See more at: http://physics.ucsd.edu/do-the-math/tom-murphy-profile/#sthash.NdPH91PV.dpuf
Tom Murphy is an associate professor of physics at the University of California, San Diego. - See more at: http://physics.ucsd.edu/do-the-math/tom-murphy-profile/#sthash.NdPH91PV.dpuf
Iron

??? thx for ur answer... i was thinking in terms of dynamos v alternators???

 

Iron

?????

With a tail on a horizontal system, does it generally orient itself perpelndicular or parellel? What is the main pupose of the tail?

Thanks very interesting talk.

 

This is the answer to question 2. A tail centers it in the windstream and is what identifies a windmill as being able to rotate to capture wind from different directions.

 

Iron

?? I like your design on slide 20. I assume you monitor angular position to activily solenoid retract the blade on the return.
I'm not sure about your comment about putting two on the same slot (I'm trying to imagine the geometry). Referring to my previous post: Betz's law (1919) says that no turbine can capture more than 59.3% of available kinetic wind energy. That's becuase if we captured 100% of the wind's energy we would bring the air flow to a stop which would block any further flow of air into the turbine.

Platinum

Could you expound on why you prefer a vertical axis system?

 

Iron

???could u elaborate on AC over DC generation. advantages and disadvantages. thx

 

DC systems can be used to charge batteries or drive a DC load. AC is the alternating current, like from the household sockets. Circuitry is needed to turn AC into DC for battery charging. Circuitry is also needed to turn DC into AC (an inverter) for household device use.


Both are OK as long as you have the right circuitry in place.

Iron

?? Is there any progress in minaturizing a wind system?

 

There are small wind systems, but power is limited. Energy attainable is dirctly proportional to the cross sectional area exposed to the wind so smaller isn't better here.

 

Iron

???could u elaborate on AC over DC generation. advantages and disadvantages. thx

 

Iron

could u elaborate on AC over DC generation. advantages and disadvantages. thx

Iron

?????

With a tail on a horizontal system, does it generally orient itself perpelndicular or parellel? What is the main pupose of the tail?

Thanks very interesting talk.

Iron

A Storage system such as a battery bank. Now we have to consider DC/AC conversion.

Iron

Staying with AC only, Governers and limiters would work fine.

 

Iron

With a tail on a horizontal system, does it generally orient itself perpelndicular or parellel? What is the main pupose of the tail?

Thanks very interesting talk.

Iron

With a tail on a horizontal system, does it generally orient itself perpelndicular or parellel? What is the main pupose of the tail?

Thanks very interesting talk.

Iron

Hello,  -- Please prefix any questions with a question mark or two so I can more easily pick them out....

 

Iron

good overview Thanks Jon.

Iron

Very interesting.  Thank you.

Iron

Thanks Jon, this is always an interesting topic.

Iron

?? Is there any progress in minaturizing a wind system?

 

Iron

@ccrider  What is that company that repairs electronics for wind generators?

Iron

Thank you Jon. Very interesting.

Iron

Jon, thank you.  Interesting overview. 

Vary the pitch according to wind speed.

Iron

use low demand high out periods to pump water up hill to a storage system and use potential energy of water to drive generators in high demand low out periods

Iron

Staying with AC only, Governers and limiters would work fine.

 

Iron

Windmill? Maybe "Indutrial Wind Turbines" these days -- at least the Grid-Tie systems.

AT 150Meters tall they are behemoths.

Iron

The system would have a certain amount of angular momentum, which will even out gust power inputs.

A Storage system such as a battery bank. Now we have to consider DC/AC conversion.

Iron

Change the pitch or angle of attack on the blades.

Iron

Jon's question was: What can be used to offset variations in windspeed?

Blogger

?? slide 12. Is this equation specific for only three bladed horizontal axis designs?

Like an Electric Motor Vehicle

Iron

governer and/or blade pitch

Iron

There is no single "braking system" -- feathering, eletromagnetic and mechanical (rotor) brakes.

Iron

By vatying the pitch of the blades

Iron

To slow down with wind, change the blade pitch.

Iron

By changing the pitch

 

Iron

Brakes? Feathering of blades?

By varying the pitch of the blades

Iron

Jon's question was: How do modern windmills slow themselves down in high wind?

Blogger

@MazianLab: See here: http://www.mnr.gov.on.ca/en/Business/Renewable/2ColumnSubPage/276957.html

just don't believe everything you read there.

Iron

plane orientation of the blades aligns to the direction of rotation

Iron

MazianLab:

Yes ontario publishes a wind atlas on the MOE site.

Iron

Does it have a weather station on it?  Usually they have a small wind vane on top to measure the wind direction.

The company I work for repairs turbine electronics.  It's a big business for us.

Iron

I think rotating axis windmills have a weathervane tail.

Platinum

Is there any website that we can see average wind speed in our area?

Iron

Jon's question was: How can you tell by looking at a windmill if it has a fixed
axis?

Blogger

New wind turbine installations are being installed all over the state. Last year a wind farm began operation on Fire island near Anchorage

Don't know but Betz's law (1919) says that no turbine can capture more than 59.3% of available kinetic wind energy. That's becuase if we captured 100% of the wind's energy we would bring the air flow to a stop which would block any further flow of air into the turbine.

Platinum

I think most wind turbines are in the 1.5MW to 2.5MW these days -- land based -- typically 400' to 550' high.

Iron

Jon's question was: Approximately what percentage of the cross-sectional area do the blades represent?

Blogger

Question: Which one of Vertical or Horizontal wind Turbine has more efficiency?  

Iron

Good afternoon, everyone

Iron

Hello from Toronto, Ontario!!

Iron

Hi all -Audio is live! If you don't see the audio bar at the top of the screen, please refresh your browser. It may take a couple tries. When you see the audio bar, hit the play button. If you experience audio interruptions and are using IE, try using FF or Chrome as your browser. Many people experience issues with IE. Also, make sure your flash player is updated with the current version. Some companies block live audio streams, so if that is the case for your company, the class will be archived on this page immediately following the class and you can listen then. People don't experience any issues with the audio for the archived version.

Hello from West Point, PA, USA.

Iron

good afternoon from Ontario

 

Iron

g'day from sydney, australia. i just want 2c my name in print :)

Iron

Greetings from sunny California

Iron

Please use ?? at the start of your questions for Jon so he can find them.

Iron

Good afternoon from partly rainy FL

 

Iron

hello from Edmonton, Alberta

Iron

Hello from Henderson Nevada

Iron

S. Fosty fr Ontario Canada

Iron

Good Morning from wet sloppy Valdez. It's the Monsoon season

Hello from Summerville, South Carolina. How's everyone doing?

Iron

Aloha from Montana with a sunny cool 70s

Platinum

Greetings from Boston Metro West. A steamy 93 degrees F today!

Iron

Greetings from Midland, Tx

Iron

Be sure to follow @designnews and @DigiKeyCEC on Twitter for the latest class information. We encourage you to tweet about today's class using the hashtag #CEC.

Blogger

Steamy Baltimore Maryland USA here

Iron

Howday from Ft Worth, TX

Iron

Good evening from Valladolid, Castilla y Leon, Spain

Iron

Please join our Digi-Key Continuing Education Center LinkedIn Group at http://linkd.in/yoNGeY

Blogger

The streaming audio player will appear on this web page when the show starts at 2 PM Eastern time today. Note however that some companies block live audio streams. If when the show starts you don't hear any audio, try refreshing your browser. If that doesn't work, try using Firefox or Google Chrome as your browser. Some users experience audio interruptions with IE. If that doesn't work, the class will be archived immediately following our live taping.

Blogger

Good afternoon, everyone

Iron

Hello from sunny SE Lake Simcoe Ontario Canada. Hot and muggy!

Iron

Be sure to click 'Today's Slide Deck' under Special Educational Materials above right to download the PowerPoint for today's session.

Blogger

Good morning from Huntsville, Al.

Iron

schap1, good morning I'am from upstate NY whats your location?

Good morning from Scottsdale,AZ

Iron

Good morning from sunny Edmonton, AB

Iron

Good morning from upstate New York.

Iron

Morning from Portland Oregon

Iron

Good morning from Mobile, AL

Had to replace my DSL modem. Bummer. Got caught up from archives.



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