Converting waste industrial heat into useful energyPublished On: Tue, May 17th, 2011 | Energy Science | By BioNews
Billions of dollars lost each year as waste heat from industrial processes can now be converted into energy, scientists say.
The high-efficiency thermal waste heat energy converter actively cools electronic devices, photovoltaic cells, computers and large waste heat-producing systems while generating power, says Scott Hunter, who leads the development team at the Oak Ridge National Lab.
“In the US, more than 50 percent of the energy generated annually from all sources is lost as waste heat,” Hunter said. “So this actually presents us with a great opportunity to save industry money through reduced fuel costs while reducing greenhouse gas emissions.”
Hunter’s technology uses structures that are about one mm square in size. About 1,000 of these energy converters can be attached to a one-inch square surface such as a computer chip, concentrated photovoltaic cell or other devices that generate heat, according to an Oak Ridge statement.
Although the amount of power each device can generate is small, ranging from one to 10 milliwatts, many arrays of these devices can be used to generate sizable amounts of electricity that can power remote sensor systems or assist in the active cooling of the heat generating device.
The underlying concept, pyroelectricity, is based on the use of pyroelectric materials(which generate a temporary voltage when heated or cooled), some of which have been known for centuries. But these studies have been plagued by low thermal to electricity conversion efficiencies – from about one to five percent.
However, Hunter’s team expects to achieve efficiencies of 10 to 30 percent.