Illustration showing how waste heat could be used to generate energy

From waste heat to energy

November 14, 2018
This article appeared in Berkeley Engineer magazine, Fall 2018

Nearly 70 percent of the energy produced in the United States each year is wasted as heat, much of it emanating from computers, cars or large industrial processes. But now, researchers led by Lane Martin, professor of materials science and engineering, have developed a thin-film device that converts waste heat from electronics into energy, using a process called pyroelectric energy conversion. The team synthesized thin-film versions of materials just 50 to 100 nanometers thick and then, together with the group of Chris Dames, associate professor of mechanical engineering, fabricated and tested the pyroelectric device structures based on these films. Accurately measuring the properties of thin-film versions of pyroelectric systems had been a challenge, but these structures allowed the engineers to simultaneously measure temperature, electrical currents and source heat to test the device’s power generation capabilities. The results suggest that, for fluctuating heat sources, the thin film can turn waste heat into useable energy with higher energy density, power density and efficiency levels than other forms of pyroelectric energy conversion, particularly from high-speed electronics.