Thermoelectrics Make A Comeback—New concepts and materials…power generation

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http://pubs.acs.org/cen/science/89/8925sci1.html

June 20, 2011 | Volume 89, Number 25 | pp. 33 - 35

Thermoelectrics Make A Comeback

New concepts and materials invigorate a commercially active but obscure field specializing in heating, cooling, and power generation

Mitch Jacoby

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In the early 1960s, long after the curious collection of properties that define thermoelectric materials was discovered, manufacturers began producing specialty cooling and power-supply devices largely based on the thermoelectric properties of bismuth telluride, Bi2Te3. This niche market, which mainly served the military and aerospace industry, didn’t disappear, but the next 30-plus years witnessed a steep drop in interest in the topic.

“In the mid-1990s, universities rarely taught thermoelectrics in physics courses,” Kanatzidis points out. He adds, “It was a forgotten concept. Now it’s finally coming of age.”

After years of sitting mostly unnoticed in a quiet corner of science, thermoelectrics is again drawing attention. In addition to supplying temperature management and power products to the military and aerospace industry—for example as miniature coolers that chill the infrared detectors central to the imaging electronics in heat-seeking missiles and night-vision systems—the few manufacturers in this area now make millions of units each year for down-to-earth civilian use. Their products are found in climate-control automobile seats offered by major automakers, thermal cyclers for polymerase chain reaction systems, and power generators for applications far from an electrical grid.

At the same time, researchers in industry and academia, motivated by recent fundamental materials advances, are focusing their synthesis, analytical, and engineering skills on discovering new thermoelectric materials and designing new ways to use them. They hope these advances will provide enhanced thermoelectric performance and lead to a broader range of products. Despite key advantages of thermoelectric power and cooling systems relative to conventional ones—for example, they have no moving parts, making them mechanically simpler, and they do not emit greenhouse gases or depend on environmentally harmful coolant fluids—only a narrow range of thermoelectric products has been commercialized. One of the field’s much talked about goals is to make thermoelectric devices that work well at high temperature and can generate electricity cost-effectively from waste heat recovered, for example, from industrial plants or automobile exhaust.

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