A performance evaluation of the ejector refrigeration system based on thermo-economic criteria through multi-objective approach

This work investigates an exhaust heat-driven ejector refrigeration system with the thermo-economic considerations. The system is thermally modelled and is optimized considering the performance coefficient and the total annual cost as two objectives using heat transfer search algorithm. Generator temperature, evaporator temperature and condenser temperature are considered as design variables. A 2-D shock circle model is used to simulate the ejector component with R245fa refrigerant. The results of multi-objective optimization are discussed using the Pareto frontier obtained between both conflicting objective functions. The effect of varying the nozzle throat diameter and the ecological function on the thermo-economic objectives is presented and discussed. The sensitivity analysis of the objective functions to the decision variables is investigated. Further, the exergo-economic results at the optimal point are also presented and discussed. The results reveal that the ejector and the generator are the leading contributors to the exergy destruction and hence to the total annual cost. The coefficient of performance and total annual cost at the best optimal point are 0.3 and 25,903 $/year, respectively. The optimized product unit cost of the system is 53.8 $/GJ with 10.5% exergy efficiency. Graphic abstract