Converting Waste Heat Into Useful Electricity
November 28, 2012

Tetrahedrites Could Be The Next Big Thing In Thermoelectrics

April Flowers for - Your Universe Online

A team of Michigan State University researchers has developed a new thermoelectric material — a material which converts waste heat into useful electricity — by using common materials found pretty much anywhere dirt is present.

This is an important discovery, the team says, because the vast majority of heat that is generated in energy production is lost. Take for example a car engine, the vast majority of heat generated is lost through the tail pipe. The thermoelectric material would take that waste heat and turn it into something useful, like electricity.

Donald Morelli, a professor of chemical engineering and materials science, led the team in the development of the new material based on natural minerals known as tetrahedrites.

“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. “The mineral family that they mimic is one of the most abundant minerals of this type on Earth — tetrahedrites.

“By modifying its composition in a very small way, we produced highly efficient thermoelectric materials.”

The drive to develop new thermoelectric materials has been ongoing for some time. Some new, more efficient materials have been discovered recently, but Morelli says many of those are not suitable for large-scale applications because they were derived from rare or exotic materials, or the synthesis procedures are complex and cost prohibitive.

“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.”

The MSU team took a different approach, using very common materials and grinding them to a powder. These powders were then compressed into usable sizes with pressure and heat.

“It saves tremendously in terms of processing costs,” Morelli stated.

This discovery could pave the way to many new, low-cost thermoelectric generation opportunities, the team says. Applications of the new material 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.

The findings of this study were published in the online journal Advanced Energy Materials.