218101 Study on optimization of device structure in a high pressure microchannel heat exchanger

Development of a small and high efficient heat exchanger, which is utilized in a fuel battery and a heat pump system for CO_2 refrigerant and so on, is strongly required. In authors' previous study, the prototype of the stacked high pressure resistance microchannel heat exchanger manufactured with diffusing bond technique has been proposed. The objective of the present study is to reveal flow and heat-transfer properties of counter-flow microchannel heat exchangers which have rectangular cross-sectional channels with 250×250μm and 500×500μm. Pressure drop and heat transfer rate are measured as flow and heat-transfer properties, respectively. As the results, it is found that heat transfer rate increases with increasing of number of stacked layers of the device. Heat transfer rate of the present heat exchanger with high- and low-temperature water as working fluids is higher 2 kW than that of the existing heat exchangers.