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Heat to electricity to heat to …

September 22nd, 2010 by Gene

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If you sneer at science fiction, think again. Interchangeable electricity and heat. Today, on Engineering Works!

Science fiction has always been full of nifty gadgets that would almost work in real life. Almost, but not quite. Put away your skeptical hat. Engineers are turning some of these far-out gadgets into reality.

How about a jacket that uses your body heat to charge your cell phone? Or a tiny power plant that uses the heat from your apartment to light your living room?

These science fiction-sounding items are theoretically possible. They use something called the thermoelectric effect to turn heat into electricity and electricity into heat. In the past these gadgets have been too inefficient and too expensive to be worth developing. That’s changing as the cost of energy gets higher.

Now, engineers are using nanotechnology to pull off this heat-into-electricity-into-heat trick. They start with a high-tech alloy, bismuth antimony telluride, and crush it into really tiny particles. You could line up a-thousand of them across the end of a human hair. Then they press it into a wire or tape.

What’s important here is that these new wires conduct electricity with almost no heat. This is what makes thermoelectric devices practical.

The engineers working on this new generation of thermoelectric devices are looking ahead to a time when thermoelectric coolers will replace refrigerators and thermoelectric power generators will be standard equipment for any green house.

Thermoelectric or not, our effect is running down. See you next time.

EngineeringWorks! is made possible by Texas A&M Engineering and produced by KAMU-FM in College Station. Learn more about engineering. Visit us on the World Wide Web.

http://engineeringworks.tamu.edu

Start the discussion: Some things, like interchangeable heat and electricity, used to be something you’d only see in science fiction. Now, physicists understand that it does work that way, and soon you and I may be using it. What kinds of application might use this phenomenon?

For more:

http://en.wikipedia.org/wiki/Thermoelectric_effect

http://newenergyandfuel.com/http:/newenergyandfuel/com/2008/03/25/what%E2%80%99s-that-thermoelectric-effect-and-why-is-it-so-important-now/

http://technologywonk.com/2007/giant-thermoelectric-effect-in-graphene/