Handheld windmills serve as electric generators

admin » 14 March 2007 » In Uncategorized »

From a piece by Lisa Zyga on physorg.com:

As a clean, free, and natural option, harnessing wind power for use as a source of energy is appealing, although it’s usually considered on a large scale. Windmill farms with 100s of giant windmills have been built to supply partial power to towns, but wind power can also have simple applications on a small scale. For example, some bicycle lights work by wind power, but the electromagnetic converter they use requires large amounts of mechanical energy, which is not available for most applications

[S]cientists Robert Myers, Mike Vickers, Hyeoungwoo Kim, and Shashank Priya from the University of Texas Arlington have recently investigated other possible designs that might make a small-scale windmill feasible. To convert wind energy into electric energy, they use a piezoelectric structure, where bimorphs (thin plastic sheets) aligned in a row are caused to vibrate via a lever and crankshaft which is attached to the wind vanes.

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The scientists’ most promising design so far involves three 5-in. (13-cm.) fans mounted on a single shaft through an adjustable gear ratio. Attached to the shaft, a crank arm pulls a lever that is attached to two rows of nine bimorphs. The lever causes the bimorphs to vibrate, converting random wind flow into synchronous mechanical motion. The entire generator size, which is 3.5×4x5.5 in.3, is made of acrylonitrile butadiene styrene (ABS) plastic.

At an average wind speed of 10 mph, the windmill can generate 5 mW of continuous power at a rate of 12 volts. Although a fairly small amount of energy, the windmill can still power sensors, switches, alarms, and wirelessly transmit data, which would be especially useful in remote locations. Further, the generated power can be stored in a supercapacitor for delayed use, and minimally works at wind speeds as low as 5.4 mph.

- snip-  The scientists predict that small-scale windmills can supply energy for powering weather stations, lighting inside tunnels, and monitoring national borders.

“We have recently implemented a wind-powered wireless sensor network using this system,” said Priya. “We are currently working on a design which will enhance the power density by one order of magnitude. The challenge is in capturing the mechanical energy from wind effectively.”

Link via Futurismic

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