Transient supercooling behaviors of a novel two-stage Peltier cooler

A new design concept is proposed to enhance the transient supercooling performance, in which variable leg cross-sectional areas are introduced into two-stage TECs. Since the cross-sectional area ratios of hot end to cold end for the hot stage (gamma(h)) and the cold stage (gamma(c)) can be larger, smaller, or equals than/to 1, nine designs with various combinations of gamma(h) and gamma(c) are investigated. A three-dimensional multiphysics model is used to compare the transient supercooling performance of the nine designs at various pulse amplitudes and widths. The results show that as compared with the conventional TEC with a constant cross-sectional area, the new design significantly reduces the cold-end temperature (T-cc) and employing variable cross-sectional area in the cold stage is more effective for reducing T than that in the hot stage. Design with gamma(h) > 1 and gamma(c) > 1 yields the lowest T-cc among the nine designs. The reduced T-cc can be attributed to the fact that the variable cross-sectional area makes the current density and thermal resistance asymmetrical such that more Joule heat transports to the hot end due to its larger cross-sectional area. The cooling performance of the design with gamma(h) > 1 and gamma(c) > 1 is additionally enhanced by increasing yh and ye.