Refrigeration Characteristics of R448A and R404A in High- and Low-Temperature Test Chambers

The refrigeration systems in high-and low-temperature test chambers face challenges of high energy consumption and low efficiency. This study developed an enhanced vapor injection system in a test chamber and conducted experiments using R448A and R404A refrigerants to improve the system efficiency and ensure its alignment with low-carbon environmental goals. The impact of refrigerant charge amounts and compressor frequencies on system performance was analyzed. The results demonstrated that the cooling capacity and coefficient of performance(COP) of the R404A and R448A systems initially increased and then decreased with increasing refrigerant charge amounts. The R448A system demonstrated an 11.3% higher maximum cooling capacity and a 10.4% higher COP than the R404A system. In addition, the compressor power consumption of the R448A system was lower than that of the R404A system. At a refrigerant charge amount of 2.0 kg, the R448A system consumed 7.5% less power than the R404A system. The refrigeration capacity of the R448A system exhibited a 7.7% higher increase compared with that of the R404A system, whereas the compressor power consumption increase was 1.9% lower than that of the R404A system.