Low Thermal Resistance Cold Plate for Thermal Management of High-Heat-Flux Electronics

In this study, a mechanically pump-assisted capillary-driven two-phase cold plate was fabricated to overcome limitations of conventional two-phase cooling technologies in high-heat-flux electronics applications. The cooling mechanism inside the cold plate was based on thin-film evaporation from wicks. The wicks were continuously supplied with liquid refrigerant R245fa using a mechanical pump. Eight heaters simulated the electronics’ heat load and were located on both sides of the cold plate. Eight wicks were positioned within the cold plate, with the thin film evaporation region located directly across from each heater. Each evaporator was a modulated porous wick structure consisting of thick regions responsible for low-pressure drop coolant supply and a thin layer for low thermal resistance evaporation. A phase separator separated the pumped liquid from the vapor space and, in turn, prevented flooding of the thin film evaporation region. The cold plate demonstrated the removal of heat fluxes exceeding 1.18 kW/cm2 over heater footprint areas less than 0.12 cm2 while operating with a low pumping power of 1.04 W. Highly uniform thermal resistances of less than 0.08 K/(W/cm2) were achieved, making the present cold plate attractive for the thermal management of high-heat-flux electronics. The excellent uniformity of thermal resistance indicates independent heat removal from individual heaters, enabling future electronic devices to operate at higher electrical power beyond the state-of-the-art by mounting more heat sources (i.e., chips) on the cold plate.