Thermo-economic and environmental analysis of a refrigeration system operating with ecological refrigerants

This thesis presents a mathematical model of a vapor compression refrigeration system operating under steady-state conditions. This model was used to design an energy-efficient system, with low cost, that operates with the most appropriate ecological refrigerant in terms of overall environmental impact, focusing the refrigerants R290, R600a, R744, and R1234yf. The environmental analysis was performed based on Total Equivalent Warming Impact, while the thermo-economic analysis was performed based on Coefficient of Performance, Exergy Efficiency, and Total Plant Cost Rate. For the reference cooling capacities evaluated, the thermo-economic and environmental analysis indicated that the system with R290 has higher energy, exergy, environmental, and economic performance among the evaluated systems for the studied thermodynamic conditions. Therefore, the system operating with R290 is the most suitable to replace systems with R134a. Finally, analyzing the three cost rates related to Total Plant Cost Rate in each system for both reference cooling capacities analyzed, it was noted that the operational cost rate was the most relevant cost, while the penalty cost rate due to carbon dioxide emission was the least relevant cost.