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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.
And now for a really interesting renewable energy concept: kite gen. Would have made Newton smile :)
They who would give up an essential liberty for temporary security, deserve neither liberty or security - Ben Franklin
I recently was looking at microturbines for my urban house recently and decided it was a bad idea because of the noise they make when the wind isnt going fast and people are trying to sleep - woosh...woosh...woosh...woosh...
I wonder if this makes a noise. buzzzzzzzzzzzzzzzzzzzzzzzzz
I have decided to use these instead of microturbines and added a pivot and tail so it can turn with the wind direction, and put 20 up on my roof. Would be interesting to see how the buzz multiplies. Would I be living under a swarm of bees?
(In fiction at least) The Subways Of Tazoo, Colin Kapp, 1964. In the story, it was strings rather than ribbons. The story involves an alien race that killed themselves by climate change. Tsk, what science-fiction twaddle!
One line blog. I hear that they're called Twitters now.
Are you kidding? I could build one of those! Well, maybe. Anyways the cost is magnitudes different from what I saw, and it looks to be user-repairable. Probably doesn't kill birds, either. Regarding the claimed efficiencies, I am not a scientist, but I learned from Tesla that efficiency increases with frequency. That thing was humming.
The cost of that cleanup, of course, will be borne by taxpayers, not industry.
The only sure way to help countries of the third world is for countries like the US to open up their subsidized markets. The corn market in the US for example is subsidized to an extent of almost 10 billion dollars in 2005!
If third world countries got just half of that market, a lot of lives would be changed.
Not too dumb. He was designing it for use in Haiti. While I suspect there are places where nothing is tenable, a thin ribbon under tension is a whole lot simpler and cheaper to manufacture and maintain than a rotating wind turbine. It doesn't have to be mylar, you could use scrap cloth, although mylar may last longer and be easier to keep under tension. LED's were for the demo. You could use the thing to run any light; or better yet charge a small battery so you have power on demand.
He made another good point in the article: If you break this you have something that a local can fix. If you break a solar panel, your stuck with a broken panel (which is trash). What he didn't mention is that this would run at night too, as opposed to a solar panel that only works during the day.
while I agree with another poster's comment that the 30x improvement in efficiency over a microturbine is probably not real, I think it's fairly interesting. Enough so that, since IAAAP (I am an applied physicist), I'm thinking about building one myself to get some numbers and see how well it scales. I know some people in Africa who might be interested in something like this...
My guess is that generators in series can't easily be synchronized, but generators in parallel would tend to self-synchonize (assuming near-identical construction and side-by-side location).
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It's so Popular Mechanics. Another resonant oscillating generator.
This is an old idea, but the usual form is a free-piston engine. Popular Mechanics was hot about that one back in 2004. For something that will light two LEDs, that thing looks big and expensive. Note the machined aluminum frame. For comparison, here's a toy wind generator kit ("convert a plastic bottle to a wind generator!").
Notice how the guy with the vibrating ribbon generator demonstrates it in front of an electric fan. On high. That's probably because it only works in a strong wind. People generally don't live where winds are regularly that high. Wind speed in Port-au-Prince has been between 9 and 12MPH all day, so something that cuts in around 9MPH is needed for use in Haiti.
The classic cheapie generator is taking an oil drum, cutting it in half, and using that as a Savonius rotor. Then you get an alternator from a car, and there's your actual generator. The axle sticks up into the air, where the halves of the oil drum collect the wind and turn the alternator. Here's a smaller version.
Wind power is very well understood. The power in the wind is (1/2)*p*A*v^3. Where p is air density in units (kg/m^3), A is the swept area in units (m^2) and v is the velocity of the wind in units (m/s). This is intuitive from a physics perspective if the energy of a moving object is (1/2)*m*v^2 then p*A*v is mass. Albert Betz proved that the maximum efficiency of a wind generating device is 59%. Many small wind turbines can achieve an efficiency of over 30%. From the article it says "his device [is] 10 to 30 times as efficient as the best microturbines" That would put the efficiency of the device at at least 300%. Not only is that higher than the betz limit it is higher than the energy available. A quick example. Lets use an air density of 1 and a swept area of 1 (for a rotary turbine this would be a blade radius of .56m), a wind velocity of 10mph (4.47 m/s) and an efficiency of 30%. This will make 13.4 watts of power. That would be enough to power several small led light.
Well, the simplest way to build a wind generator, is to buy a 3 foot diameter 36V cooling fan for a large stationary diesel motor and mount that on a post. Add a big diode and hook it to a 12V battery. If you are a bit more careful, then add an over-voltage cut-out switch. To power a sea/lakeside cottage, this is all you need. A 36V fan will charge a 12V battery better in low wind (It won't ever get to 36V, not even in a storm with no load). The post bearing is just a pipe slid over the mast, it can be a loose fit, add some grease to eliminate squeaks, add a vane at the back and run the cable down loosely with a plug, so you can unwrap the wire once a month. KISS.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
One of the neater aspects about this project is that you can build it out of trash you have laying around. Salvage magnets from headphones or speakers, salvage magnet wire from a motor, build the frame out of whateverthehell you have laying around, and use a strip of waxed silk or something for the ribbon. You need a little bit more know-how to turn that into DC, but that's also very basic, and the components could also be salvaged from just about anything. Hell, same thing with LEDs. Let's face it, people in the third world are superb scavengers -- look at the sudden proliferation of satellite dishes made from hammered-out cans that popped up in Afghanistan after we toppled their regime.
A modern wind turbine can also be supplied in kit form and assembled with absolutely minimal tools... like nothing but a large hex wrench.
Yes, the parts are complex, but the interconnections between them are not.