Sparks for Your Stride: Kinetic Energy Conversion News

by Julian Rollins

Whether it’s clubbers on the dance floor, soldiers on the go, or just lonely long-distance runners, energy harvested from toiling muscles is a hot topic. Until recently, prototypes have relied on high-impact movements to generate any current to speak of. But the race is on to harness power from the slightest swish of a skirt, twist of a wristwatch or shrug of a shoulder.

The US National Science Foundation has offered a $350,000 grant to researchers at the University of California-Berkeley, who are developing microscopic piezoelectric fibers that could be woven into any garment. The research team claims that a million fibers spun into a shirt would generate enough current to power an iPod. So far the team, led by Professor Liwei Lin, has succeeded in converting energy from small finger movements using fibers attached to a glove (see a video demonstration of this in Smart Planet’s “Future of Cloth” report here). The Pentagon is also backing the project, in the hope that it will put an end to heavy battery packs for soldiers.

Berkeley’s nano-sized generators (via Azo Materials)

The technical term for the conversion process is piezoelectricity – from the Greek piezo, meaning ‘to squeeze’. Mechanical stress is applied to a material, which generates an electric field in response. Maintaining the current depends on a continuous movement to and fro, like the swing of a foot.

Microfibres aren’t the only application for the science. Researchers at Princeton and the California Institute of Technology have embedded tiny chips into silicone sheets that, they claim, could be surgically implanted in the body, harnessing movements as slight as the rise and fall of the lungs.

Yi Qi, a postdoctoral researcher at Princeton University, holds a piece of silicone rubber imprinted with super-thin material that generates electricity when flexed. The technology could provide a source of power for mobile and medical devices. (Credit: Frank Wojciechowski via Science Daily)

Coming soon…

• A supple, six gram power generator created by an engineer at Louisiana Tech University that can be fitted into the heel of a trainer, offering added shock absorption while converting the runner’s energy into voltage for direct use or storage in batteries. Developer Ville Kaajakari claims that the generator is capable of producing up to 10 milliwatts – comparable to the laser of a DVD player – and costs less than a dollar to manufacture. (View a video of a prototype here.)
  
  
• Authorities in the French city of Toulouse are trialling kinetic energy pads set into pavements to power street lights. They use modules first developed by Dutch company Sustainable Dance Club, which converts the thud of clubbers’ dancing feet into electricity.
  

Editor’s Note: This post originally appeared on Green Futures. Images and links added by Worldchanging.

Image Credits:
Image of microgenerator in shoe heel via Ville Kaajakari’s website.
Bottom image of diagram of Sustainable Dance Club’s floor module via Rob Aid.

For more on kinetic energy news in the Worldchanging Archives, see:

• Kinetic Energy Cell?
  
• EnOcean’s Wireless Piezoelectrics
  
• Motion As Power
  
• Harnessing the Power of the People
  
• The Pavegen: Harvesting the Power of Footsteps

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(Posted by Green Futures in Energy at 5:00 PM)

View full post on Worldchanging: Bright Green