Wind Farms - Page 3 - PeachParts Mercedes-Benz Forum

cmac2012 · #31 02-22-2009, 11:40 PM

Quote:

Originally Posted by t walgamuth

The turbine blades are adjustable for angle of attack. I have timed the blades on the ones north of Lafayette. They turn at 18 RPM and it appears they always turn the same speed. I have heard they turn them parallel to the wind and don't operate when the wind is too high, but I have not heard what speed that might be.

At 18 RPM, with blades over 100' in length, I have heard that that equals to near 200 mph at the tip. I'd say birds would have a hard time dodging that kindof speed, even in the daylight, unless they were smart enough to fly around them.

Those pics look just like the windmills here.

I come up with about a third of that:

100' blade, scribes an arc of approx. 320'. At 18 rpm that's 5760' per minute or 345,600 per hour. About 65.5 mph.

Still nasty. I've heard many times that the newer bigger ones are supposed to be easier on birds than the altamont pass cuisanarts, the older, small, more rapid windmills. But I have no observational knowledge of that.

Chas H · #32 02-22-2009, 11:45 PM

A 100' blade is the radius, plus the hub. So the arc would be at least 628 feet. And the tip speed of over 130 mph.

mgburg · #33 02-23-2009, 12:36 AM

128.519 m.p.h. is more like it...

100' * 2 = 200' Diameter

Diameter * pi = ≈ 628.318' traveled by tip of blade in one revolution

628.318' * 18 r.p.m. = ≈ 11,309.733'/min.

11,309.733' * 60 min. = ≈ 678,584.013'/hour

678,584.013'/hr. / 5,280'/min. ≈ 128.519699 m.p.h.

That thar blade is wackin' birdies at about terminal velocity!

Obviously, near the center of the hub, they'll break their little necks like running into a glass window, but then...if that's the case, maybe we need to eliminate all glass windows 'cause I have actually seen birds smackin' windows and they suffer quite a bit before they finally spaz their last spaz...unless "Frisky" grabs and gobbles and grinds them up before they finish their little spazzin'...

mgburg · #34 02-23-2009, 12:38 AM

Quote:

Originally Posted by cmac2012

I come up with about a third of that:

100' blade, scribes an arc of approx. 320'. At 18 rpm that's 5760' per minute or 345,600 per hour. About 65.5 mph.

Still nasty. I've heard many times that the newer bigger ones are supposed to be easier on birds than the altamont pass cuisanarts, the older, small, more rapid windmills. But I have no observational knowledge of that.

You're the woodworker here...I can see why you measure twice before you cut once!!!

pawoSD · #35 02-23-2009, 02:31 AM

Yeah....birds smash into all kinds of stuff. I've had them hit the windows on our house (and at my parents house) numerous times....dumb birds. Never had one disabled or die because of it though, they just always fly away. One bird banged the window like 4-5 times (not very hard) then got the idea and turned around.

t walgamuth · #36 02-23-2009, 06:13 AM

I don't know the exact length of the blades, I have heard 120' plus maybe 5' of the hub.

Figure that in and you are at 150 mph blade speed at the tip.

Botnst · #37 02-23-2009, 07:36 AM

Quote:

Originally Posted by pawoSD

So....if windmills are out, then how do you propose we generate power without clouding up the atmosphere? Solar is an option, but for now one windmill can make the same amount of juice as MANY solar panels....not to mention they also work at night.

I don't believe that windmills are "out", I simply believe that all relevant factors should be taken into account.

I do have serious problems with solar panels because they rely on selenium, a highly toxic element. Mining and refining it is dangerous and can have serious environmental consequences. Disposing of it is a serious problem. Putting them on houses in "tornado alley" is asking for problems, IMO. Again, I'm not saying solar panel should not be used. I do advocate taking into account the full cost of implementation.

Same with Cd and Li batteries, etc.

cmac2012 · #38 02-23-2009, 09:07 PM

Quote:

Originally Posted by Chas H

A 100' blade is the radius, plus the hub. So the arc would be at least 628 feet. And the tip speed of over 130 mph.

Oh well, the post I responded to said "blades over 100' in length," but you're right, if that's the radius, the speed would be double.

cmac2012 · #39 02-23-2009, 09:09 PM

Quote:

Originally Posted by mgburg

You're the woodworker here...I can see why you measure twice before you cut once!!!

Please refer to post #24 and see if you can find the word "radius."

However, if I'd thought for a moment, I would have remembered that there are three blades, each of them extending only one direction. I was thinking of something like the older airplane propellers, one blade extending both directions from the center.

mgburg · #40 02-23-2009, 10:27 PM

Quote:

Originally Posted by cmac2012

Please refer to post #24 and see if you can find the word "radius."

However, if I'd thought for a moment, I would have remembered that there are three blades, each of them extending only one direction. I was thinking of something like the older airplane propellers, one blade extending both directions from the center.

I know...I was yanking your woodworkers' belt there!!!

I know...I'm a smartass!

kknudson · #41 02-23-2009, 10:28 PM

Quote:

Originally Posted by Botnst

I don't believe that windmills are "out", I simply believe that all relevant factors should be taken into account.

I do have serious problems with solar panels because they rely on selenium, a highly toxic element. Mining and refining it is dangerous and can have serious environmental consequences. Disposing of it is a serious problem. Putting them on houses in "tornado alley" is asking for problems, IMO. Again, I'm not saying solar panel should not be used. I do advocate taking into account the full cost of implementation.

Same with Cd and Li batteries, etc.

Solar panels, until recently, was not considered truly energy positive for general use (full life cycle).
There are some that say the Windmills are not that energy positive over their entire life (I can't believe that, but I have read references to it).
As mentioned earlier, dams screw up fish.
Ethanol (A real live government joke) isn't very "Net" energy positive.
Hy-Brid cars are not really an answer, most reading I have done says they are actually "Net" carbon negative compared to one of the hi mileage vehicles, for ex the Mercedes diesels that get better mileage.
Even fuel cells in their current vision, are not really all that energy positive.

Thats the problem with everything, there are tradeoffs, we have to hopefully get the most bang for the buck.
Probably via a mix of each, maybe in their appropriate location / use.

And yes, a full life cycle analysis needs to be done, and proven.

But there are some promising ideas, ideas
Safe Nukes
Fuel via Algae

And an article I read the other day made a great case for improving our efficiency.
We could easily reduce our overall energy needs by 20% by operating more efficiently, better lights, furnaces, tighter houses, fuel efficient vehicles etc etc. The article said we could push 50% reduction if we went all out at it.

Botnst · #42 02-23-2009, 11:24 PM

^^^^ I couldn't agree more.

cmac2012 · #43 02-23-2009, 11:47 PM

Quote:

Originally Posted by mgburg

I know...I was yanking your woodworkers' belt there!!!

I know...I'm a smartass!

You?? Nahhhh . . .

Emmerich · #44 02-23-2009, 11:54 PM

Quote:

Originally Posted by ForcedInduction

Wind farms are great for killing birds. Its also expensive and unreliable.

I read that on average the blades turn about 12% of the time. I was surprised at how low that number is. Not sure if they include down time for repairs or that is down time due to lack of wind.

cmac2012 · #45 02-23-2009, 11:55 PM

Quote:

Originally Posted by pawoSD

So....if windmills are out, then how do you propose we generate power without clouding up the atmosphere? Solar is an option, but for now one windmill can make the same amount of juice as MANY solar panels....not to mention they also work at night.

Solar panels are not nearly as cost efficient as concentrated heat solar power, such as with parabolic trough mirror systems, and better yet, the new Linear Fresnel Reflector:

http://jcwinnie.biz/wordpress/?p=2470

I say "cost efficient" because solar panels have other efficiencies, such as the advantage of being practical in small scale, say the size of the top of a house and they install and operate with much less work.

One of my fantasies is to secure $$ to research how small a Fresnel or similar system can be and still be cost effective. They don't spoil the horizon like wind mills and are silent, for the most part. You could have them close to neighborhoods, even.

One web bit I found stated that this method uses steam only as a transfer medium whereas the parabolic trough systems, the big ones now in use, instead heat some kind of oil to around 700, perhaps 900 degrees F, I forget, which makes some sense as you'd have some heat left after dark to continue to produce elec.