Scientists at the University of Utah have worked out a way of convert waste heat into sound and electricity.
Physicist Orest Symko and his research team has succeeded in building small devices that turn heat into sound and then into electricity. According to Symko,the heat-to-electricity acoustic devices are housed in cylinder-shaped "resonators". Each cylinder, or resonator, contains metal or plastic plates, or fibres made of glass, cotton or steel wool which are placed between a cold heat exchanger and a hot heat exchanger.
Heat builds up and moving air produces sound. This sound can be converted into electricity.