R-32, Fin-and-Tube Heat Exchanger, Refrigerant Flow Distribution, Heat Pump
In this study, the refrigerant flow distribution characteristic of fin-and-tube heat exchanger used as outdoor and indoor heat exchanger of a residential heat pump air-conditioner was experimentally studied and analyzed. The outdoor heat exchanger included â€œn shapeâ€ 1 -circuit, 2-circuit and 3-circuit arrangements, and the indoor heat exchanger was only â€œn shapeâ€ 2â€“ciucuit arrangement. It showed that the refrigerant flow distribution of both outdoor and indoor heat exchanger as evaporator would give much more system performance change of the residential heat pump air-conditioner than that as condenser. The refrigerant flow distribution characteristic can be expressed with the difference value of each circuit exit superheat as evaporator. The maximum difference value with little effect on system performance had been obtained both under cooling mode and heating mode. The maximum difference value was nearly the same at various test conditions and can be considered as 3â„ƒ. According to the experimental results, the system performance under heating mode especially for rated heating mode had more sensitive with refrigerant flow distribution characteristic than that under cooling mode, therefore the adjustment of refrigerant distribution characteristic of both the outdoor and indoor heat exchanger should mainly base on the rated heating mode.