Article ID: 24-33LG
In recent years, zeotropic mixed refrigerants have become a strong candidate for next-generation refrigerants due to restrictions on conventional refrigerants to reduce global warming. The refrigeration oil used in the compressor is selected for its compatibility with refrigerants to return to the compressor more easily. However, it is also known that the dissolution of refrigerants into refrigeration oil cause a change in the physical properties of the mixture, which affects the performance of the refrigerant compressor. Therefore, to realize early conversion to next-generation refrigerants, it is necessary to find out how refrigerants dissolve in refrigeration oil to ensure that compressors work well and are reliable. Especially for zeotropic mixed refrigerant, the dissolved composition may differ from the original composition. This study aimed to reveal the dissolution behavior of zeotropic mixed refrigerants into the refrigeration oil. The experiment was set to measure the dissolved composition at saturation condition and compare the dissolved composition at the initial dissolution state and at saturation condition. R454C, a mixture of R32 and R1234yf, was used as the zeotropic mixed refrigerant, and POE oil was used as the refrigeration oil. The measurement results showed that the refrigerant dissolved in the refrigeration oil had almost the same composition as the charged before mixing. However, when the dissolved composition was measured in the pressure range below the dew point at a liquid temperature of 80℃, the amount of R1234yf was approximately 4% higher than that of the charged composition. Furthermore, at a liquid temperature of 80℃, the liquid phase separation with different refrigerant mixture ratios was observed in the solubility range from 67% to 82%.
