Experimental and Theoretical Assessment of Inverter-Operated Split Air Conditioner with Low GWP Alternative Refrigerants

This article presents experimental evaluation and comparative analysis of low GWP alternative refrigerants, namely HC-290 (propane), HC-1270 (propylene), HC/HC-1270 blend, and HFC-32 (difluoro methane) as drop-in replacements for HCFC-22 (Chloro difluoro methane) in a typical 1.5 TR capacity inverter operated split type air conditioner (SAC). The experimental setup consisted of retrofitting an original HCFC-22 test unit following the soft optimization of the SAC system for each alternative refrigerant, followed by testing under controlled operating conditions as per the IS 1391, Part-1 standard at the half capacity and the rated capacity of inverter SAC. The results obtained were compared against the baseline HCFC-22 test unit. The optimized SAC gave EERIS (Indian Seasonal Energy Efficiency Ratio) of 4.63 for HC-290, 4.71 for HC-1270 and 4.87 for HC-290/HC-1270 blend, respectively increased by 8.94 %, 10.82 % and 14.58 % compared to HCFC-22. HFC-32 delivered the maximum cooling capacity of 6.78 kW, 3.67 % higher than baseline unit at the rated capacity. HC-290/HC-1270 blend exhibited the lowest power consumption and discharge temperature amongst all the refrigerants considered. The charge of flammable refrigerants has been optimized below LFL satisfying EN378 standard for the safety of inverter SAC in domestic applications.