The energy systems we use in our daily lives are notorious for bleeding that energy in the form of heat, like radiators that heat buildings and vehicle exhaust systems. Researchers from Penn State and the National Renewable Energy Laboratory have developed a flexible thermoelectric generator that can wrap around pipes and other surfaces to reclaim that wasted energy more efficiently.
“A large amount of heat from the energy we consume is essentially being thrown away, often dispersed right into the atmosphere,” said associate VP (Penn State) of research Shashank Priya. “We haven’t had cost-effective ways with conformal shapes to trap and convert that heat to useable energy. This research opens that door.”
Thermoelectric devices are created using small couples, each resembling a table with two legs connected, typically forming a flat, square device with no flexibility. The team designed their thermoelectric device using six couples on a thin substrate. A flexible metal foil was then used to connect 12 strips together, creating a device with 72 couples. Liquid metal was then poured in between the layers of each strip to increase its efficiency.
Tests carried out using the new device on a gas flue exhibited a 150% higher power density over other thermoelectric units. A scaled-up version, measuring over 3-inches squared, maintained a 115% power density advantage. According to the scientists, that version produced a total power output of 56.6 W when placed on the hot surface. What’s more, the liquid metal placed between each layer of the device can be tailored for different heat sources, allowing for maximum efficiency.