Domestic ejector air-conditioning system performance using different ejector and refrigerant type.

Abstract

Improvement in refrigeration system performance could be achieved by reducing compressor workload by using ejector. Hydro chlorofluorocarbons (HCFCs) refrigerant (R22) which contributes to heat global warming, and ozone depletion need to be replaced with eco-friendlier hydrocarbon (HC) refrigerant (R290). The system performance analyses were done using two ejector designs, constant area mixing (CAM) and constant pressure mixing (CPM) using both R22 and R290 refrigerant. Several air temperature were set ranging 18°C to 29°C. CAM resulted in better performance than CPM with R22 20% higher cooling compared to R290 at 23°C setting. Due to low requirement of mass flow rate in R290, it reduces the ejector performance in the secondary inlet and lowered cooling capacity with high compressor load. Thus, the entrainment ratio of the CAM with R290 is significantly lowered by 12.70%, 13.35%, 16.39%, 14.74%, and 7.93% compared to R22 at air temperature setting, respectively. The optimum performance was obtained at refrigerant temperature 12.67°C with air temperature setting 23°C. The coefficient of performance (COP) demonstrated the same trend accordingly. Higher COP is required because it equates better efficiency, hence reduced compressor energy. This is due to the saturated vapor entering compressor which increased cooling capacity in the evaporator.