Experimental comparison of the refrigeration performance of R32 and R410A in full and partially filled conditions

Abstract

This paper details an experimental investigation performed on an inverter driven air-conditioning laboratory setup that was tested with both R410a and R32 refrigerants. The experimental test rig is an evolved version of that reported in Grech that now uses a compressor from an inverter driven R410a air-conditioner and also incorporates a variable flow orifice from a Variable Refrigerant Flow (VRF) system. The performance of the new R32 refrigerant (lower Global Warming Potential (GWP)) is compared to the older R410a refrigerant that is being phased out (GWP of R32 is only one third of R410a). The effect of operation of the air-conditioner in partially filled conditions was experimentally tested to emulate unit operation under leak conditions. That is the partially filled condition was simulating partial loss of refrigerant from the system as happens when leaks develop and refrigerant mass is lost from the system. A high enough loss of refrigerant would of course result in a high enough degradation in refrigeration performance and therefore the user would eventually call for maintenance and repair. However the operation of the system under partially filled conditions might be over a prolonged period of time as typically refrigerant leaks are very slow and small. R32 is also a single component refrigerant and therefore it cannot be effected by variability in concentrations of its primary components as can be the case for R410a. When comparing the investigations carried out and the results obtained for R410a and R32, it was observed that R410a performed better at a higher refrigerant charge, while R32 was slightly superior when the system was running at lower refrigerant charge level. Nonetheless, the difference in the values obtained between the two were slight. Therefore, it results that R32 is an ideal candidate to replace R410a due to similar performance characteristics with the benefit of having a lower GWP.