New Method for Harvesting Electricity from Waste Heat

By Evan DickScientists at the Oak Ridge National Laboratory in Tennessee have successfully developed a new method for generating electricity from waste heat. The technology, which scientists believe could achieve efficiencies of 10% –30%, relies on pyroelectricity—the capacity of certain materials to generate temporary voltage when heated or cooled.

In this device, a pyroelectric polymer is sandwiched between two electrodes. One electrode is attached to the heat source, while the other is suspended. Electricity is generated as the polymer warms and cools as heat passes through the device.

Applications for this device—which measures only a few millimeters long—may be found in cooling and powering laptops or in converting solar heat absorbed by photovoltaic solar panels, but not used by them.

The Lawrence Livermore National Laboratory estimates that 55% of all the energy generated in the U.S. in 2009 was lost to waste heat, suggesting that a much wider range of applications is possible. Previous efforts to produce power from waste heat have achieved only 2% efficiency.