Using light to transfer heat between objects

IEEE Spectrum : Besides conduction and convection, a third option for transferring thermal energy is light. Although once thought too weak to be useful, heat transfer via radiation works well when the two objects transferring energy are placed close together, say Michal Lipson of Columbia University and her colleagues. Despite the difficulty involved in maintaining large thermal gradients over nanometer-scale distances, the researchers have succeeded by using high-precision microelectromechanical systems to separate nano-sized beams of silicon carbide. When the SiC beams were spaced 42 nm apart, the researchers achieved a heat transfer almost 100 times as strong as that predicted by conventional thermal radiation laws. The technology could have many uses, including converting the waste heat in a car’s combustion engine to electricity and controlling the temperature of delicate nanodevices.