Thermal optimization of an air-cooling heat exchanger utilizing manifold-microchannels

Over the past few years there has been a steep upward trend in power consumption in electronic equipment, which in turn has led to more dissipation of heat. The current air-cooling technology has started to show limitations for high heat flux cooling. On the other hand, there are still barriers to the adoption of liquid-cooling technology such as higher procurement and operational costs, reliability issues, and also danger of coolant leakage. In this paper, a new approach in air-cooling utilizing a manifold-microchannel is discussed. Manifold-microchannel heat exchangers have demonstrated the potential to provide very high heat transfer capacity for significantly less pumping power and volume compared to conventional heat exchangers. In order to fully utilize the potential of manifold-microchannel technology, a multi-objective optimization was performed to calculate the optimum design variables with the objective of maximizing heat transfer density (Q/VΔT) and coefficient of performance (COP/ΔT). For the optimization process, an approximation-based optimization was utilized. In addition, a hybrid method was employed for the numerical modeling. The method is based on combining computational fluid dynamic (CFD) simulation in the microchannel and 1-D momentum and mass balance equations in manifolds. The optimization results indicate that the optimized air-cooling manifold-microchannel heat exchanger can provide significant improvement compared to the state-of-the-art air-cooled technology for the case of base area of 1cm² or larger.