Turning background room temperature heat into energy
(PHYSorg.com Physics)

Every time we convert energy from one form to another, part of that energy is lost in the form of heat. Trying to efficiently get that energy back is very difficult once it is lost to the environment. Thermoelectric devices can change heat energy into electricity, and vice versa. But to capture energy from heat efficiently, these devices typically need to work at high temperatures with a large temperature difference.