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Monday, December 05, 2005 Free Power for CarsAutomakers look to thermoelectrics to help power tomorrow's vehicles. By Kevin Bullis
Converting heat directly into electricity is nothing new; it has been possible since 1821. But thermoelectric materials have been too inefficient to make them practical for anything but a few niche uses, such as in deep space probes. Recent advances using nanotechnology, however, have revived this moribund field, and have car makers such as General Motors and BMW taking notice, hoping to increase fuel efficiency and eventually replace alternators and possibly even internal combustion engines with thermoelectric generators. "I think right now that thermoelectrics have a good chance of succeeding," General Motors senior analyst Francis Stabler reported last week at the Materials Research Society meeting in Boston. As much as 70 percent of the fuel energy burned up in car engines doesn't go toward moving the vehicle along or powering the CD player, he said. Instead, it's dissipated as waste heat. Stabler says a new generation of thermoelectric materials can convert heat to electricity well enough to be used for taking the burden of electricity generation off the engine, thereby saving fuel. Researchers still need to find ways to make these materials cheaply and consistently, however, before they can be widely deployed. But certain niche uses could help the technology get established. Already, Amerigon, a Deerborn, MI manufacturer, has sold well over a million car seat heating and cooling units that use an older version of the technology. When electricity is applied to thermoelectrics materials they transfer heat, cooling an area or heating it depending on the direction of the current. If the next generation of thermoelectric materials can be manufactured inexpensively, they could be used in more demanding applications. Wrapped around a car's exhaust pipe, for instance, they could harvest waste heat to produce electricity. Initially, this electricity might be used to supplement the electricity generated by the vehicle's alternator, making it possible to run more electrical devices without adding more strain to the engine. If the technology proves to be reliable, Stabler says, it could eventually replace alternators altogether and run electrical water and oil pumps, relieving the extra work for the engine, boosting performance, and saving fuel. John Fairbanks, technology development manager at the U.S. Department of Energy, suggests that if all GM cars alone used this technology, it would save roughly 100 million gallons of gas per year.
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Comments
Guest (Harold Wicks) on 12/05/2005 at 8:07 PM
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It should find uses in micro CHP (Combined Heat & Power) in homes & businesses to air-conditioning (cooling) and refrigeration without any wear prone moving parts the Seebeck and Peltier effects being complementary.
No effort should be spared if there is the remotest prospect of realizing such high efficiency devices.
Guest (Jeffrey Zucker) on 12/05/2005 at 9:06 PM
1
Guest (Harold Wicks) on 12/05/2005 at 8:07 PM
1
It should find uses in micro CHP (Combined Heat & Power) in homes & businesses to air-conditioning (cooling) and refrigeration without any wear prone moving parts the Seebeck and Peltier effects being complementary.
No effort should be spared if there is the remotest prospect of realizing such high efficiency devices.
Guest (Jeffrey Zucker) on 12/05/2005 at 9:06 PM
1
Don Stephens on 02/07/2007 at 3:05 PM
1
Does anyone have knowledge of the temps and temp differentials being utilized by this research... i.e., how hot does the heat-source surface have to be on that exhaust pipe (or engine block or catalytic converter)?
(I'm not really very interested in its application to ICEs, but if the differential is low enough, I see being able to tap heat in pvs, solar thermal collectors, not to mention wood and pellet stoves, to produce by-product at-site-of use electricity... : )