Oscillating thermal switch using electrostatic forces

Abstract

Thermal control devices such as thermal switches, thermal diodes, thermal regulators and thermal capacitors can control the intensity and direction of heat flow, which has proven useful in various thermal management applications. Their operation is analogous to that of their electrical counterparts, where temperature differences correspond to voltage differences and heat flow corresponds to electric current. Here we design and fabricate a thermal switch that controls the heat flow from the heat source by changing the thermal conductance when switching ON and OFF. The thermal switch uses electrostatic forces for actuation and makes thermal contact between the heat source and the heat sink when in the ON state, and breaks contact when in the OFF state. The thermal switch is constructed using the commercially available materials. The heat sink and heat source are made of silicon, and the active part of the heat switch is a flexible gadolinium sheet with a thickness of 161 µm. The proof-of-concept device was evaluated for a magnetocaloric application; however, the proposed thermal switch can be used in any thermal circuit for fast thermal regulation and advanced thermal control.