| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 98 === An investigation of micro-channels fin-and-tube evaporator design using CO2 as working fluid is described and a design program is also developed. The design method is based on thermal balance design. Because there is neither fin-and-tube evaporator for CO2 nor the experimental results, apply water as working fluid in the program, and compare the design results with experimental results. Then using the same procedure design the micro-channels fin-and-tube evaporator for CO2. For CO2, after the dryout quality, the heat transfer coefficient decreases by quality increasing. And it can’t achieve thermal balance design. According to this reason, the heat transfer coefficient in the dryout region is not included in thermal balance. Moreover, CO2 heat transfer coefficient is high, and it makes the resistance between air side and refrigerant side unbalanced. The heat exchanger for water is not suitable for CO2.
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