Computational and Experimental Investigation of Thermal Coupling Between Superlattice Coolers

Thermal coupling between superlattice coolers (SLCs) in an array adversely affects performance of an each individual cooler compared with an isolated device. Here, we have developed an electrothermal model to study this coupling between SLCs and how it is affected by geometric parameters such as separation between the superlattice structure and a ground electrode, and operating parameters such as the convective heat transfer coefficient and the activation current applied for driving the SLC. Complementary to the modeling efforts, we have also experimentally studied thermal coupling between SLCs in a microfabricated array under various conditions. Simulation results are critically compared against the experimental data and yield the conclusions of importance for an optimized design of the hybrid microfluidic SLC cooling scheme for thermal management of multiple clustered hotspots in microprocessors. We have observed more than 60% reduction in cooler performance, when placed within the few characteristic diameters of the ground electrode, due to thermal coupling effect. Thermal properties of the working fluid have even more pronounced effect on the thermal coupling between the coolers.