While studying fundamental properties of matter in the course of their day-to-day research, a team of scientists have discovered a novel approach to crafting higher thermoelectric efficiencies, which can help develop electricity from waste heat, such as that emitted by internal combustion engines, known as the Seebeck effect.

University of Johannesburg Department of Physics Professor André Strydom collaborated with researchers from the Chinese Academy of Sciences, in Beijing, the Institute of Solid State Physics, in Vienna, the Max Planck Institute, in Dresden, and the University of Aarhus, in Denmark, on the discovery.

“The Seebeck effect has in recent years found its way into everyday life. Refrigerators [with] no electric motor or compressor and no moving parts have already started becoming available commercially. There are also sustainable cooling technologies such as portable cooling boxes,” he said, adding that the phenomenon described the generation of an electric potential in a conducting material when exposed to a temperature gradient.

“Equally fascinating is the reverse effect, namely the spontaneous cooling down that one end of a thermoelectric material experiences when an electric potential is applied across its two end points,” Strydom added.

However, turning waste heat into electricity was an equally compelling challenge for scientists, he advised.

“As an example, motor vehicles in cities across the planet expel copious amounts of waste heat from their internal combustion engines. That heat can be useful if it is turned into electricity.”

In the authors’ work to understand certain unusual features in their fundamental studies of strongly correlated electron systems, an obscure relation was found between the mobility of charge carriers in metal and its Seebeck effect. It is this relation that paved the way for a new route to develop electricity from sources such as waste heat from vehicle engines.