Performance Analysis of an Ejector Based Hybrid Air-Conditioning System Integrated with Solar Thermal Collector

Electricity saving potential of a residential air conditioning system based on a solar hybrid ejector-vapour compression refrigeration cycle operating with R245fa is investigated. The ejector refrigeration cycle of hybrid system is working with heat input from an integrated evacuated tube solar thermal collector which can produce temperature in the range of 60 to 100°C. Thermodynamic simulation of the vapour ejector flow is done using Engineering Equations Solver (EES) software to get its critical entrainment ratio and corresponding area ratio for various temperatures of evaporator and generator. The simulation results in terms of entrainment ratio is compared with published results to get maximum relative error within 3.1%. With evaporator temperature of 16°C and condenser temperature of 35°C, the critical entrainment ratio varies from 0.20 at 60°C generator temperature to 0.82 at 100°C generator temperature. The corresponding area ratio increases from 3.9 to 13.2. It is observed that for a given condenser temperature, and area ratio, the critical entrainment ratio increases with evaporator temperature but decreases with generator temperature. Analysis of the ejector refrigeration cycle with above range of operation shows that the refrigeration effect produced increases from 0.26 kW at generator heat input of 1.49 to 2.65 kW at heat input of 4.37 kW. Further, the analysis on one-ton hybrid air-conditioning system with ejector refrigeration producing its share of refrigeration system using solar heat input in the range of 60 to 90°C can lead to a compressor power saving in the range of 7.5 to 51.15% in comparison with standard vapour compression system of its kind.