Microwind Generator For Low Power Systems

An anonymous reader wrote in to say that "Shawn Frayne, has developed Windbelt, efficient, cheap lowpower wind generator built out of taut kite fabric." Everyone has seen the video where the suspension bridge is ripped apart by wind- his idea was to use the same thing to generate power. I doubt I'll be running my desktop off it any time soon, but it's a cool idea.

Sub-100W generators are very interesting...

[DamonHD]

...but it is not at all clear what their efficiency or $/Watt or manufacturing cost will be. Although absolute efficiency is maybe not critical for many applications given that the wind is free, cost is important in, for example, third-world deployments.

See the discussion here for example: http://www.fieldlines.com/story/2007/10/13/9445/4984 [fieldlines.com]

Much as I'm intrigued by this let's not get into perpetual motion machines nor "beating Betz" just yet! In particular the "30x as efficient as the best microturbines" claim in TFA is particularly suspect: I have a VAWT made from a cardboard cereal packet in my back garden that probably extracts 10% of the available energy.

Rgds

Damon

Dupe, sortof

[Snefru2]

This turbine was one of the items mentioned few days ago on Slashdot in another post. See: http://science.slashdot.org/article.pl?sid=07/10/11/212243 [slashdot.org]

A bit more detail

[AndroidCat]

Shawn Frayne's Windbelt Wins Popular Mechanics 2007 Breakthrough Award [scribemedia.org]

Re:Macro wind power: Kite Gen

[Futile Rhetoric]

It's an interesting concept, but it also seems utterly impractical to me. Kilometer-long lines zipping around at high speeds would mean that no aircraft can pass through the area under 1000m, it'll wreak havoc on any birds passing through, and it seems to me that if you're going to have several of these, they'll need to be far enough apart to keep the lines from getting entangled -- which of course means a drastic increase in the required area for the windfarm. And yes, I know of course that normal wind turbines aren't exactly bird-friendly either, but at least they don't reach to the same heights.

Not a Single Engineering Reply

[BoRegardless]

There was not any engineering detail to go on from the video, I agree. But trashing the idea without getting the numbers is bad science, more akin to the nightly news.

The whole concept is interesting, because it can work with wood and cloth instead of mylar and aluminum. The "first world" part would be the magnet, coils and the DC rectifier/converter to allow a user to likely charge a battery.

How many of these generators and how big they would be to extract a usable 10 watts of charging power in a 5-10 mph wind hasn't been defined, but with a couple models, that can be determined.

You never learn anything by bitching. Buckling up and testing is the way this & other ideas will be understood and improved. For the 3rd world, just a minimal LED lamp array can make the difference between studying at night or not.

Re:Macro wind power: Kite Gen

[Anonymous Coward]

Didn't read the linked web page, did we? Come on, admit it.
Seems to me vtcodger was not commenting on the article at all, but on the technology mentioned in SubZero992's post.

Re:Macro wind power: Kite Gen

[wvmarle]

Traditional wind farms (using wind turbines) are apparently not much of a problem for birds. I recall a study done years ago in The Netherlands, where some environmental protection group wanted to see how much damage the wind turbines were doing. The startling result: nearly nil! The explanaition: birds will not fly into the turbines because they are warned by the noise.

Now how that would hold up with the kites I don't know. My only experience is with kiting at the beach: we could sometimes see seagulls make sudden movements to avoid our line. I don't think they can see it, possibly they can hear it. I've never had a seagull or other bird actually hit my line when kiting.

Wouter.

Re:And how exactly does the science work?

[ashitaka]

The reference to the Tacoma Narrows bridge is very relevant. Galloping Gertie showed that even without hurricane-force winds a very heavy ribbon-shaped strip can me made to move in an extreme fashion due to mechanical resonance. Even a small strip would have the same kind of resonance so that large relative movement can be extracted from even light winds.

Haven't you ever made a blade of grass whistle between your thumbs?

Re:Not a Single Engineering Reply

[Bucc5062]

Fine, then make one and truly answer the parents post. He/she talks about how people were trashing the idea, but not by applying actual effort to prove or disprove, just unsubstantiated opinion.

I am not an engineer, I do not think I could build this, but were I capable I'd try it out and start to look at the numbers.

1 - It was said it would not work in low winds (5/10 mph) because the demo used a fan. Prove it I say. it may be a combination of material tension and mass of the magnet.

2 - It was said it would buzz. Prove it. Build one and measure the decibels produced. Can the sound be dampened without losing efficiency.

3 - It was said it was not 30x efficient. Prove it. Build one and compare it to other micro wind generators (though the video indicated there were few out there)

I know this is /. and most times we don't read the article, we have varying opinions, but it does surprise me that out of all the eggheads on this blog list, there are not some who could duplicate the experiment and show results. until proven differently, my opinion is that this device is a cool idea worthy of more review, and an example of genuine innovation.

Um, did you not read the article you linked to?

[SIIHP]

"but now I see from the Wikipedia article that resonance has nothing to do with it"

Did you read the whole article, because you seem to have missed this part,

"The wind-induced collapse occurred on November 7, 1940 at 11:00 AM(Pacific time), due partially to a physical phenomenon known as mechanical resonance."

Re:Nah, this is dumb

[Artifakt]

You could use the thing to run any light; or better yet charge a small battery so you have power on demand.

I got a couple of battery re-chargers for AA - C and 9 volt, and started recharging for all my flashlights, MP3 players, and such a few years ago. Last year, I rigged them to a small solar array, so those apps are now completely off the grid. I cold probably have used a very small wind turbine just as well, or an adaptation of a widget like the one in the article. With a good supply of batteries, I can afford to wait a bit for a sunny day, so solar's what I went with. I doubt I'm saving the environment much, if at all, given manufacturing costs of the devices, but I keep seeing the whole idea dismissed on the basis of that one argument about ecological fitness, or related argeuments about scaling.

Meanwhile, if the local power grid goes down for a day or three, I have some things which will still run, including a bit of light and an emergency radio.

It's like another, 1,000 year older tech adaptation. I also have a fireplace in my house. I don't heat with it on any regular basis, but I have a hinge mounted, cast iron widget with a hook on the end that can swing over the fire, so I can cook over it pretty expediously. The fireplace is never going to be an energy efficient way of routine heating for millions of people now using gas or electric heat. It doesn't fix any of the current problems related to old infrastructure, global warming, and overpopulation. Scaling arguments are actually negative (if we all go back to burning wood, we'll screw up the environment more, not less), but my fireplace will keep a few people warm or a very cold night without power, and even give them some hot soup or cocoa. If we do have a lengthy outage in the winter, The chimney's clean, I have a couple of ricks of wood already cut, and an axe if I need more, and we'll probably not just manage for ourselves, but put up the little old lady across the street on our couch, take some hot soup to another neighbor or two, and so on. Plus the radios mean I'll know what sort of problem it is early, and can plan. I'll know if the problem is expected to last long enough that I'd better conserve the chainsaw for real emergencies, etc.

I'm not even sure but what that IS a potential huge net ecological savings. People who cope on their own if the big, gridded systems go down aren't as likely to be a drain on emergency services. What's the carbon footprint of a helicopter rescue operation?

I'm starting to think scaling arguments are mostly rubbish anyway. Whenever we start addressing scaling, we're talking about getting up to sizes where someone can centralize the production, and rent services to the common people. A stable, long term sustainable, ecologically sound system shouldn't assume centralized control is desirable, in fact, all other things being equal, it's a bad thing.

Re:Macro wind power: Kite Gen

[slim]

I find it hard to see how this "kite" technology works. At such a height, any movement from the air foil would be diminished to a few degrees or less at the generator on the ground.

Check this [susx.ac.uk] paper (PDF) about neural net / genetic algorithms for steering power kites.

"The common element between current proposed traction kites applications is that
the aerodynamic forces developed by the kite are transferred via the lines to perform
work at near-ground level. This could be either the direct acceleration of large masses
such as cargo ships, or the turning of a dynamo as the taut lines slowly spool out
from a reel."

For the reel dynamo, you'd have a power generating reeling out phase, and a power draining reeling in phase -- but for the latter phase you can depower the kite so you make an energy profit overall.

I find the idea of massive cargo ships towed by arrays of huge power kites much more thrilling, however.

Re:Macro wind power: Kite Gen

[0111 1110]

Birds are not noted for their advanced intelligence.

Au contraire mon ami [slashdot.org] Aussi. [edge.org] Convinced yet? [myspace.com]

Re:Wrong solution

[Jesus_666]

Doesn't change the fact that a lot of people would probably rather have access to a little bit of electricity without having to rely on fiendishly expensive solar cells than hope that at some point in the future industrialization will come and make their lives better.

If you can't make large improvements that doesn't mean you can't try to make small ones. Not everyone gets to save the world, but some people can make it a slightly better place. Even though this device won't make Tanzania export leader I'm pretty sure that, if deployed, it could improve the lives of a number of people.

Re:Wrong solution

[ibbey]

To the shown apparatus generates too little power to be of any use at all.

None, huh? So why does he show the device powering a radio and a clock in the video? You're right, 40mW isn't much power, but according to the video the device costs $2-$5. For that price, you can easily build a few of them & you start to get to a more useful amount of power. But even 40mW is enough to do things like maintain the charge on a cell phone or charge a flashlight. I'm sure someone with more knowledge of low power systems could come up with even more useful ideas. Is 40mW enough to power a small water filter? I bet it is if it's designed properly. And remember, the generator can run 24/7 (wind permitting, at least), so it can be used to charge a battery for times when you need more current for short periods of time. Seems like it might have some use after all...

Re:Macro wind power: Kite Gen

[Whiteox]

Australian pigeons have been known to hitch a ride on cars going through Sydney city tunnels. Sp I don't see why birds can't avoid windmills.