Almost every device that needs energy also wastes energy. Cars get their zip by burning gasoline, but that process heats up the car — and that heat is wasted energy. Computer batteries get hot when they’re in use; so do cell phones and kitchen appliances. All that hot air adds up: The U.S. Department of Energy estimates that more than half of the energy generated in America will be wasted, mainly as lost heat.
But where some see waste, Zhong Lin Wang sees opportunity. Wang is an engineer at the Georgia Institute of Technology in Atlanta. He thinks energy can be harvested from all that lost heat, and he’s built a device to prove it.