研究期間：10101~10112;This is a two years period research project. The thermal and flow characteristics of supercritical CO2 refrigerant in microchannel heat exchangers will be analyzed experimentally. The flow pressure drop and heat transfer performance of supercritical CO2 in a single microchannel have been tested and the fundamental data base of supercritical CO2 was established in the first year. In the second year, the microchannel heat exchanger will be designed and fabricated. It performance will also be tested. It is expected that the results of this project will be applied by the local research institutes and manufacturers for related air-condition and heat pump system design.