Thermoelectrics could harvest car's heat
R Colin Johnson
12/21/2010 11:48 PM EST
PORTLAND, Ore.—Today's state-of-the-art thermoelectrics are only about 5 percent efficient, but new research indicates that a class of material called skutterudites—plus a new technque for aligning their atoms—could improve thermoelectric efficiencies to as much as 20-percent, enough for commercialization.
Such high-efficiency thermoelectric converters on the exhaust pipe of an automobile, for instance, could convert enough heat into electricity to charge the batteries of a hybrid vehicle.
Sutterudites conduct electricity well, but conduct heat poorly. However, University of Michigan professor Ctirad Uher recently discovered that certain configurations of a barium alloy in the compound could drastically increase the materials' efficiency. The technique effectively lowers the thermal conductivity of skutterudites, thus drastically increasing their conversion efficiency. Uher performed the work with fellow professor Massoud Kaviany.
The researchers claim that automobile manufacturers could use their new material to harvest the heat from the exhaust pipe of an automobile to generate electricity. "That's a big source of heat that you paid for already," said Uher.
The research was funded by the U.S. Department of Energy's Office of Basic Energy Sciences and the University of Michigan's Center for Solar and Thermal Energy Conversion.
The conversion of energy between light and electricity (LEDs/solar cells) and between light and heat (light bulb/greenhouse) is complemented by thermoelectric conversion between electricity and heat.