Heat exchange characteristics of a gas-gas counterflow microchannel heat exchanger have been investigated experimentally. The microchannel has a rectangular cross section with 200 μm high and 300 μm wide. Working fluid is air. Reynolds number in the hot passage ranges from 127 to 381, and that in the cold passage ranges from 25 to 381. Temperatures and pressures at inlets and outlets of the heat exchanger have been measured to obtain heat transfer rates and pressure losses. The heat exchange and the pressure loss characteristics of the tested microchannel heat exchanger are discussed. Since the partition wall of the heat exchanger is thick comparing with the microchannel dimensions, a simple heat exchange model, the wall temperature of which is constant, is proposed to predict the heat transfer rate. The predicted heat transfer rates are compared with those of the experimental results and both results agree well.
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