Theoretical analysis of thermoelectric cooling performance enhancement via thermal and electrical pulsing

Abstract

This paper is an introduction and theoretical investigation of the fast-transient cooling characteristics of a TE module under applied high-current electrical pulses. A temperature-dependent, finite element model was developed to accurately model the fast-transient performance. Analysis of experimental data is presented to verify the accuracy and validity of the model and the conclusions derived therefrom. It has been shown that cold plate temperatures are achievable from a typical TE module beyond that obtainable by conventional, steady-state means. The cooling enhancement is by virtue of the fact that Peltier cooling is a surface effect and extremely concentrated at the cold junction, whereas, Joule heating is a volume effect and is distributed throughout the volume of the TE pellet. As such, most of the Joule heat takes a longer time to reach the cold plate than the Peltier cooling effect. This phenomenon is theoretically demonstrated by applying a high-current pulse after the minimum steady-state cold plate temperature has been established. Calculations have shown that cold plate temperatures can be reduced by 16 K below that via steady-state means. These transient enhancements are admittedly short-lived and have limited effectiveness. However, the results presented herein suggest that further exploitation of the fundamental differences between Peltier and Joule heat are possible. A concept is re-introduced which consists of thermally and electrically separating the cold electrode from the TE pellet.