Much of that heat is less than 100 degrees Celsius and emanates from things like computers, cars or large industrial processes. Engineers at the University of California, Berkeley, have developed a thin-film system that can be applied to sources of waste heat like these to produce energy at levels unprecedented for this kind of technology.

This study reports new records for pyroelectric energy conversion energy density (1.06 Joules per cubic centimeter), power density (526 Watts per cubic centimeter) and efficiency (19 percent of Carnot efficiency, which is the standard unit of measurement for the efficiency of a heat engine).

The thin-film system uses a process called pyroelectric energy conversion, which the engineers' new study demonstrates is well suited for tapping into waste-heat energy supplies below 100 degrees Celsius, called low-quality waste heat.