The purpose of this study was to clarify the performance difference factor between two sets of fin-and-tube heat exchangers, heat exchanger A and heat exchanger B, with the same specifications. The air-side and the refrigerant-side performance was experimentally investigated using R-410A and hot water to study the influence on the heat exchanger performance. The inner groove deformation of heat exchanger B in the mechanical tube-expanding process using bullets was greater than that of heat exchanger A. The capacity during condensation of heat exchanger B was 7 percent lower than that of heat exchanger A at a 1.0m/s frontal velocity. The air-side heat transfer coefficient of heat exchanger B evaluated using hot water was 8 percent lower than that of heat exchanger A at a 1.0m/s frontal velocity. Moreover, the condensation heat transfer coefficient in tube B removed from heat exchanger B was 20 percent higher than that in tube A removed from heat exchanger A at a 140kg/(m~2 centre dot s) refrigerant mass velocity. It was considered that the capacity during condensation of the heat exchanger decreased with a reduction in the contact conductance between the aluminum fin collars and the tubes. On the other hand, the capacity during evaporation of heat exchanger B was 1 percent lower than that of heat exchanger A at a 1.0m/s frontal velocity. Also, the evaporation heat transfer coefficient in tube B was 20 percent lower than that in tube A at a 200kg/ (m~2 centre dot s) refrigerant mass velocity. It was considered that the condensed water existing between the aluminum fin collars and the tube lead to the smaller performance difference between the two heat exchangers during evaporation than that during condensation.
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