Experimental Investigation of the Refrigerant Flow Distribution Characteristic of Heat Exchangers on the Residential Heat Pump Air Conditioner System Performance

摘要

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 "n shape" 1-circuit, 2-circuit and 3-circuit arrangements, and the indoor heat exchangers were only "n shape" 2-cirucuit arrangement. It showed that the refrigerant flow distribution of both outdoor and indoor heat exchanger had greatly influenced the system performance change of the residential heat pump air conditioner. The refrigerant flow distribution which was be expressed with the temperature difference value of each circuit exit superheat as evaporator with no significant effect on system performance had been obtained both under cooling mode and heating mode. The temperature difference value was nearly the same at various test conditions and can be considered as 2K. According to the experimental results, the system performance under heating mode especially for rated heating mode was the most sensitive with refrigerant flow distribution characteristic. The degradation of rating heating capacity and COP reached 26% and 14% due to refrigerant flow mal-distribution of indoor and outdoor heat exchanger. On the basis of discussion, the adjustment of refrigerant distribution characteristic of both the outdoor and indoor heat exchanger should mainly be operated on the rated heating mode.