Recycled waste heat may light up your life

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Capital News Service
LANSING – It may soon be possible to use wasted heat from your vehicle’s tailpipe to power electronics in your car, thanks to a new thermoelectric material developed by researchers in Michigan.
That’s just one of many potential uses of the new material, which is based on tetrahedrites, natural minerals found in abundance.
Thermoelectric materials are chemical compounds capable of converting waste heat into usable electricity.

According to Donald Morelli, a professor of chemical engineering at Michigan State University and the lead researcher on the project, the material provides a cheaper way to turn heat energy that would have been wasted into something useful, like electricity.
“What we’ve managed to do is synthesize some compounds that have the same composition as natural minerals,” said Morelli, who also directs MSU’s Center for Revolutionary Materials for Solid State Energy Conversion. “By modifying composition in a very small way, we produced highly efficient thermoelectric materials.”
The development of such compounds was supported by a grant from the U.S. Department of Energy and Office of Science. Partners in the project include Wayne State University and the University of Michigan.
Scientists in Ohio, California and Iowa are also involved.
Although this isn’t the first time scientists have engineered such efficient materials, many aren’t effective for large-scale applications, such as energy savings in manufacturing or power plants, according to Morelli.
“Typically you’d mine minerals, purify them into individual elements and then recombine those elements into new compounds that you anticipate will have good thermoelectric properties,” he said. “But that process costs a lot of money and takes a lot of time. Our method bypasses much of that.”
Other factors preventing progress in the use of such materials include rare or even toxic elements, as well as complex, expensive synthesis procedures.
The researchers work with common materials, grind them to a powder and then use pressure and heat to compress them into useable sizes. That saves a considerable amount of money in processing costs.
Morelli said the discovery could pave the way for many new, low-cost thermoelectric generation opportunities.
Applications could include waste heat recovery from industrial power plants, conversion of vehicle exhaust gas heat into electricity and generation of electricity in home-heating furnaces, according to the university.
Stephanie Brock, a professor of chemistry at Wayne State, said that these new materials could be used wherever heat is a byproduct.
Before these developments, there wasn’t enough efficient thermoelectric energy generated from most earth-abundant materials to make it cost-effective, Brock said.
“If you have a plug-in cooler for your car, for example, that’s a thermoelectric material but it isn’t very efficient,” she said. “Automobile exhaust is a different story. General Motors is looking at ways to use waste heat from a car to run peripheral electronics.”
Brock also said that further development and use of thermoelectric energy will greatly benefit the environment.
“Let’s say you’re burning fossil fuels to produce energy. You could increase the efficiency because some of that waste heat can be reused.
“There are certain processes where you can use recycled thermoelectric energy instead of burning fossil fuels, and thermoelectric energy does not generate emissions,” Brock said.

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