Experimental Study on Capacity Modulation by Variable Composition of Refrigerant Mixtur

摘要

A new capacity-controlled heat pump system was developed in this paper. An experimental study on capacity control of a heat pump system by variable composition has been performed using refrigerant mixture of R32/R134a. The experimental setup was made up of a refrigeration part and composition varying part. The composition varying part with a rectifier and a reservoir was connected to the junction between the condenser outlet and compressor outlet and to the throttle valve inlet. Part of the refrigerant mixture from the compressor and the condenser goes into the rectifier, as a heat source so that the heat energy to the rectifier supplied generally by external sources can be saved. When the modulation occurs, the reservoir was used to store the high volatile component of the refrigerant mixture separated from the rectifier, the low volatile component together with lubricant flows back to the main cycle. Heating capacity and coefficient of performance (COP) of the system were measured under the given conditions. The results show that about 28% of composition change was obtained. And the capacity of the system was improved by 33% as the composition of R32 increased.