Enhancement of maximum temperature drop across thermoelectric cooler through two-stage design and transient supercooling effect

In this work, a new design concept which combines two-stage design with transient supercooling effect is proposed to enhance the maximum temperature drop across thermoelectric coolers (TECs). A three-dimensional, multiphysics, and transient model is used to examine the design effectiveness. Step current pulses with various amplitudes (P) and widths (tau) are supplied to the two stages of a two-stage TEC in series. The results show that, as compared with the single-stage counterpart, a significant improvement in the maximum cold-end temperature drop (Delta T-c,T-max) is observed for the two-stage TEC. Meanwhile, the new design also greatly reduces the temperature overshoot (T-c,T-max) and increases the holding time of supercooling state (Delta t(hold)). Subsequently, effects of the pulse amplitude, width, and shape are discussed and two important geometry parameters: the cross-sectional area ratio of p-type leg to n-type leg and the leg length ratio of cold stage to hot stage are investigated. These results confirm that Delta T-c,T-max, T-c,T-max, and Delta t(hold) can be further improved by optimizing the pulse and the geometry parameters. This work provides a feasible cooling approach for some specific cooling targets, such as mid-infrared laser gas sensors or any other semiconductor devices which require a temporary but large temperature drop. (C) 2016 Elsevier Ltd. All rights reserved.