Electricity From Low-Level Heat

by Emil Morhardt

Low-level heat—temperatures 100­–200°C above ambient, the temperature range of a kitchen oven more-or-less—are abundant in the exhausts of all sorts of industrial processes from drying biomass to operating internal combustion engines. They are also much more common in geothermal fields than the higher temperatures needed for traditional geothermal steam power generation, although low-level heat can be used to vaporize high-volatility organic compounds such as propane, which can then power a turbine much as steam would. For the most part, though, this heat is wasted, just released into the environment; but it needn’t be. Researchers at the China University of Geosciences in Beijing and at Stanford University experimented with an array of commercially available thermoelectric power generators (TEGs) Continue reading