The performance of steam ejector refrigeration system based on alternative analysis

Abstract

The performance of a steam ejector refrigerator was analyzed based on an “alternative analysis”. The alternative analysis reflects an actual operation of an ejector refrigerator. In this analysis, the evaporator saturation temperature associated with cooling load was varied while the boiler saturation temperature and the condenser pressure were fixed. Form this test, the critical evaporator temperature was determined. The critical evaporator temperature is the lowest point that ejector still operated under choked flow condition. A 1 kW experimental ejector refrigerator was constructed. Variation of operating conditions and primary nozzles were implemented. It was found that the variation in operating conditions and the nozzle throat diameters significantly affected the critical evaporator temperature. Variation of condenser pressure had a strong effect on critical evaporator temperature Meanwhile the entrainment ratio in the choked flow condition was independent of the condenser pressure. The critical evaporator temperature decreased with increasing the condenser pressure and vice versa. Variations of the boiler saturation temperature and the primary nozzle throat diameter affect the mass flow of primary fluid. Either increasing the boiler saturation temperature or the primary nozzle throat diameter, the mass flow of primary fluid increased. When the primary fluid mass flow was increased, the critical evaporator temperature was reduced. On the other hand, entrainment ratio in the choked flow condition decreased. However, if the primary fluid mass flow was increased to a certain value, evaporator temperature didn’t decrease as expected.