Silicon Heat Switches for Electrocaloric Cooling

This paper presents two versions of a silicon mechanical heat switch designed for electrocaloric cooling. The first design, which consists of two 10-mm-by-12.8-mm micromachined silicon parts, allows investigation of the performance of a reciprocating solid thermal shunt device. This heat switch has a measured thermal contrast ratio in the range of 34-59. The second design adds self-alignment features that constrain the motion of the switch to facilitate fabrication and integration. The self-aligned heat switch has a thermal contrast ratio >28. It has been successfully operated for >18 000 cycles and employed in an electrocaloric cooler. Design, fabrication, and characterization of both heat switches are reported.