http://web.mit.edu/newsoffice/2009/thermoelectric.htmlYay SmartGeeks!!!!
snip:
...waste-energy harvesting might, for example, lead to cellphones with double the talk time, laptop computers that can operate twice as long before needing to be plugged in, or power plants that put out more electricity for a given amount of fuel, says Peter Hagelstein, co-author of a paper on the new concept appearing this month in the Journal of Applied Physics.
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Theory says that such energy conversion can never exceed a specific value called the Carnot Limit, based on a 19th-century formula for determining the maximum efficiency that any device can achieve in converting heat into work. But current commercial thermoelectric devices only achieve about one-tenth of that limit, Hagelstein says. In experiments involving a different new technology, thermal diodes, Hagelstein worked with Yan Kucherov, now a consultant for the Naval Research Laboratory, and coworkers to demonstrate efficiency as high as 40 percent of the Carnot Limit. Moreover, the calculations show that this new kind of system could ultimately reach as much as 90 percent of that ceiling.
Hagelstein, Wu and others started from scratch rather than trying to improve the performance of existing devices. They carried out their analysis using a very simple system in which power was generated by a single quantum-dot device — a type of semiconductor in which the electrons and holes, which carry the electrical charges in the device, are very tightly confined in all three dimensions. By controlling all aspects of the device, they hoped to better understand how to design the ideal thermal-to-electric converter.
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DiMatteo says he hopes eventually to commercialize Hagelstein’s new idea. In the meantime, he says the technology now being developed by his company, which he expects to have on the market next year, could produce a tenfold improvement in throughput power over existing photovoltaic devices, while the further advance described in this new paper could make an additional tenfold or greater improvement possible. The work described in this paper “is potentially a major finding,” he says.