Conserving energy is an important factor in industry which could lead to reduce the operating costs of the system. Improving energy efficiency is a serious concern to many researchers and numerous studies have been conducted on this goal. A valuable method to locate the inefficient system components is the conventional exergy analysis. Furthermore, to estimate the cost efficiency of a thermodynamic system, exergo-economic analysis is indispensable. This study evaluates the ejector trans-critical [Math Processing Error] refrigeration cycle from exergo-economic viewpoint. The thermodynamic system was modeled using Engineering Equation Solver (EES) software. In order to utilize the waste heat of the gas cooler, a thermo-electric generator is introduced. Energy, exergy, and exergo-economic (3E) analysis has been performed. A parametric study was conducted of gas cooler pressure, low-pressure compressor outlet pressure, and evaporator pressure. Multi-criteria optimization has been conducted to optimize COP and refrigeration cost rate using NSGA-II (non-dominated sorting genetic algorithm). The results showed the system could provide a COP of 1.593 for the base case of the cycle operation. The high-priority components to improve were expansion valve, thermo-electric generator, and low-pressure compressor which had the highest exergy destruction ratio as 0.211, 0.180, and 0.158 respectively. The refrigeration cost rate was 2.898 $ h−1 for the base case of the system. Optimization results showed that the exergy efficiency and the exergy destruction ratio of the optimum design point are 0.284 and 0.574.
