Generating electrical power from waste heat

Directly converting electrical power to heat is easy. It regularly happens in your toaster, that is, if you make toast regularly. The opposite, converting heat into electrical power, isn't so easy.

Researchers from Sandia National Laboratories have developed a tiny silicon-based device that can harness what was previously called waste heat and turn it into DC power. Their advance was recently published in Physical Review Applied.

"We have developed a new method for essentially recovering energy from waste heat. Car engines produce a lot of heat and that heat is just waste, right? So imagine if you could convert that engine heat into electrical power for a hybrid car. This is the first step in that direction, but much more work needs to be done," said Paul Davids, a physicist and the principal investigator for the study.

"In theshortterm we're looking to make a compact infrared power supply, perhaps to replace radioisotope thermoelectric generators." Called RTGs, the generators are used for such tasks as powering sensors for space missions that don't get enough direct sunlight to power solar panels.

Davids' device is made of common and abundant materials, such as aluminum, silicon and silicon dioxide—or glass—combined in very uncommon ways.