A sprawling international collaboration between scientists at government and university laboratories has resulted in a breakthrough discovery that could lead to more efficient ways of generating electricity from waste heat. The phenomenon, called the thermoelectric effect, can be applied to car exhaust, factory emissions, and other operations to capture the large amount of human-manufactured energy that is currently lost to the atmosphere.

The Trick to Thermoelectricity

A thermoelectric charge can occur when certain materials of different temperatures are adjacent to each other. It sounds simple enough, but the tricky part is to identify the most efficient materials, and to keep the difference in temperatures within an efficient range. Until recently, conventional research techniques enabled scientists to study materials based on their average atomic structure, but new nano-scale methods make it possible to study structural changes among individual atoms as materials heat and cool.

Heads Together for a Thermoelectric Breakthrough

The scientists pulled together from the federal Brookhaven, Argonne, and Los Alamos national laboratories and from Columbia University, Northwestern University and the Swiss Federal Institute of Technology. Using new modeling and experimental techniques, they were able to observe and verify a random “flipping” behavior, in which the atomic structure of certain materials rearranged to block the transfer of heat. This blocking phenomenon  is the key to thermoelectric efficiency, and the new finding will enable researchers to identify new, low cost materials to do the job.

Everyday Thermoelectricity

GM is working on new thermoelectric generators to capture waste heat from car exhaust, and at Virginia Tech, researchers are synthesizing new low-cost thermoelectric materials.  Aside from thermoelectric conversion, waste heat can also be recycled through more conventional means, for example by piping it through water tanks to create steam. Waste heat can also be vented directly to a point of use, as illustrated by the recycling of data center heat to warm an adjacent conservatory. It appears that the recycling of waste heat is on the verge of entering everyday life, and all together it could prove to be an important new energy source that enables us to reduce our use of high risk fossil fuels.

cleantechnica.com