Capturing Waste Heat from Solid Oxide Fuel Cells
Among the new technologies designed to improve energy efficiency are solid oxide fuel cells. These devices can achieve 95% efficiency or even higher, when operating at 900 ºC, but much of that heat is lost as waste. Researchers at the Swiss Federal Laboratories for Materials Science and Technology (EMPA) are working to change that though by developing thermoelectric converters (TECs) to recapture some of that energy.
Thermoelectric devices have the ability to directly convert energy stored as heat into electricity. This is because an electric current is induced when there is a temperature differential between two regions of the device. Unfortunately typical TECs only operate at temperatures below 300 ºC so the researchers are working to develop new materials that can withstand the much higher temperatures. If they succeed in finding such materials though, they could potentially increase energy output of a solid oxide fuel cell by 10%.
The researchers' ambition is not limited to just developing new TECs though as they also have an interesting idea of where to use the converters. Instead of enveloping the fuel cell with the TEC, the researchers want the cell's electrodes to be thermoelectric and recapture energy at the site of the cell’s chemical reactions.