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The replacement of HFCs using lower GWP refrigerants in the coming years is a priority to reduce the predicted climate change. The exergy analysis of vapor compression systems can help to identify the feasibility of alternative fluids in existing installations and the potential to improve them. In this sense, this paper presents an exergy analysis of an experimental setup which operates with R134a and the alternative HFO/HFC mixture R513A. The evaporating temperature is ranges between-15°C and 5°C, while the condensing temperature is set at 30°C and 35°C. In this analysis, the highest amount of exergy destruction rate is obtained at the compressor, followed by the evaporator. The maximum exergy efficiencies are observed at the condenser and the thermostatic expansion device. Finally, the average global exergy efficiency of R513A when replaced R134a in this refrigeration experimental setup is 0.4% higher (absolute difference), and with respect to the components, there is only slight reduction in efficiency in the condenser using R513A. Therefore, the R513A replacement is acceptable according to the second law of thermodynamics.

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ORC technology is one of the most promising technologies for the use of residual energy in the generation of electrical energy, offering simple and environmentally friendly alternatives. In this field, the selection of working fluids plays an important role in the operation of the cycle, whether in terms of the energy efficiency or the minimization of environmental impacts. Therefore, in this paper, a comprehensive review is presented on the use of R1234yf refrigerant and its mixtures as working fluids in ORC systems. These fluids are used in low- and medium-temperature applications for the use of residual energy generated from solar energy, geothermal energy, and internal combustion engines. It was concluded that R1234yf and its mixtures are competitive as compared with conventional refrigerants used in ORC.

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