Compact Condensers for Electronics Cooling

Multiphase heat transfer technology is one of the most efficient methods of waste heat removal in high power electronics cooling. It is especially advantageous where size, weight, and efficiency are the most important factors. A multiphase heat transfer system consists of evaporator, transport lines, condenser, and a mechanical pump in case of an active cooling system. Typically, the evaporative heat transfer coefficients are much higher than the condensation heat transfer coefficients. For example, microchannel refrigerant evaporators exhibit over a hundred thousand W/m2K, while microchannel condensers have refrigerant heat transfer coefficients on the order of several thousand W/m2K. Therefore, the condenser is the limiting component of the cooling system. Improvement of the condenser heat transfer coefficients would allow for reductions in cooling system size and weight. Military systems would especially benefit from cooling systems that are more compact and lightweight. Consequently, the objective of the proposed Phase I effort is to develop a compact and efficient condenser design with a heat transfer coefficients in excess of 50,000 W/m2K. The proposed approach is to utilize the drop wise condensation mechanism combined with a porous wick structure for condensate absorption. The Phase 1 effort begins with technical requirements definition. Based on these requirements, Thermacore will design a high efficiency compact condenser system based upon drop wise condensation and an innovative approach for removal of the condensate. The goal is to avoid film condensation as it is used in conventional condenser systems. In addition, the compact condenser design will be integrated with a loop heat pipe evaporator, processed and thermally tested. Feasibility of the condenser design will be also verified by modeling. The Phase I work will conclude with a demonstration of a 50,000 W/m2K heat transfer coefficient of the condenser system.