The thermal resonator (black box) with its radiative cooling fins across the top. The device is filled with a phase-change material that allows it to capture energy from changing temperatures. (Image: Melanie Gonick)

Thermoelectric devices generate power when one side of the device is a different temperature from the other. Instead of requiring two different temperature inputs at the same time, a new thermal resonator system takes advantage of the swings in ambient temperature that occur during the day-night cycle.

The system could enable continuous, years-long operation of remote sensing systems, for example, without requiring other power sources or batteries. The system does not need direct sunlight; it generates energy from ambient temperature changes, even in the shade. That means it is unaffected by short-term changes in cloud cover, wind conditions, or other environmental conditions, and can be located anywhere that's convenient.