Shape-Memory-Alloy Thermal-Conduction Switches

Variable-thermal-conduction devices containing shape-memory-alloy (SMA) actuators have been proposed for use in situations in which it is desired to switch on (or increase) thermal conduction when temperatures rise above specified values and to switch off (or decrease) thermal conduction when temperatures fall below those values. The proposed SMA thermal-conduction switches could be used, for example, to connect equipment to heat sinks to prevent overheating, and to disconnect the equipment from heat sinks to help maintain required operating temperatures when ambient temperatures become too low. In comparison with variable-conductance heat pipes and with thermostatic mechanisms that include such components as bimetallic strips, springs, linkages, and/or louvers, the proposed SMA thermal-conduction switches would be simple, cheap, and reliable.