Advanced electronic microcoolers

We discuss the design issues in the development of thermoelectric microcoolers for sub-200 K spot cooling applications. We start with the scaling theory for conventional microcooler configurations, and describe the practical constraints placed by contact resistances, heat rejection methods, and entropy gradients at the interfaces. We also introduce the concepts of switched thermoelectric coolers that exploit the temporal differences in the slow evolution of Joule heat and instantaneous Peltier cooling, to attain large temperature differentials.