'Thermal metamaterial' innovation could help bring waste-heat harvesting technology to power plants, factories

The thermal metamaterial represented in this graphic could make possible more efficient thermophotovoltaic devices that generate electricity from thermal radiation. Such a technology might be adapted to industrial pipes in factories and power plants, as well as on car engines and automotive exhaust systems, to recapture a portion of the energy wasted as heat. Credit: Purdue University image/ Gabriela Sincich and Matthew Bollinger

An international research team has used a "thermal metamaterial" to control the emission of radiation at high temperatures, an advance that could bring devices able to efficiently harvest waste heat from power plants and factories. Roughly 50 to 60 percent of the energy generated in coal and oil-based power plants is wasted as heat. However, thermophotovoltaic devices that generate electricity from thermal radiation might be adapted to industrial pipes in factories and power plants, as well as on car engines and automotive exhaust systems, to recapture much of the wasted energy.

In new findings, researchers demonstrated how to restrict emission of thermal radiation to a portion of the spectrum most needed for thermophotovoltaic technology.

"These devices require spectrally tailored thermal emission at high temperatures, and our research shows that intrinsic material properties can be controlled so that a very hot object glows only in certain colors," said Zubin Jacob, an assistant professor of electrical and computer engineering at Purdue University. "The main idea is to start controlling thermal emission at record high temperatures in ways that haven't been done before."

Read more at: http://phys.org/news/2016-09-thermal-metamaterial-waste-heat-harvesting-technology.html#jCp