Performance Characteristics according to the Change in Operating Pressure of the SMR Refrigerator

Demand for low temperatures below -60℃ is increasing in various places. Accordingly, SMR refrigerators are attracting attention as a way to supply them. we recognized the limitation that the study of SMR refrigerators is focused on selecting the composition ratio of mixed refrigerants. However, operating pressure is also an important factor that greatly affects the performance of the refrigerator. In this study, we attempted to understand the performance characteristics of the refrigerator according to the change in operating pressure. The experiment was conducted by changing the compressor discharge pressure to 15bar and 20bar while the compressor suction pressure was fixed to 2.5bar, and the compressor discharge temperature, power consumption, cooling time, refrigeration capacity, and COP were calculated and compared. As a result of the experiment, it was confirmed that when the compressor discharge pressure was high, the compressor discharge temperature increased due to the increase in the compression ratio, and larger power consumption was required. It was confirmed that the cooling time was faster due to a decrease in the heat exchange amount of the intermediate heat exchanger when the compressor discharge pressure was high. It was confirmed that the refrigeration capacity and COP also increased when the compressor discharge pressure was high.