Thermoeconomic Analysis of a Variable Refrigerant Flow System

Exergy and thermoeconomic analysis is an effective method for determining thermodynamic characteristics and optimizing thermodynamic-economic performance of refrigeration systems. The present study deals with exergy and thermoeconomic analysis of a variable refrigerant flow system with four evaporators used in the dairy industry. A computer code written in EEs software was used for system simulation. Impact of three refrigerants, R502, R1234ze and R134a, on thermodynamic-economic parameters of the system was investigated. In addition to calculation of exergy efficiency of refrigeration cycle for three mentioned refrigerants, effect of evaporation and distillation temperature on system exergy degradation and exergy efficiency of was also investigated. Results showed that R1234ze gas can be appropriate alternative for R502 and R134a gases. Results show that exergy destruction in compressor in reference temperature from 3.974kW for R134a refrigerant increases to 4.221 kW for refrigerant R502. Exergy destruction in the condenser in second level was calculated for all refrigerants. In thermoeconomic analysis, costs of components of variable refrigerant flow system were investigated and total costs for R134a-R502-R1234ze refrigerants were studied. It was observed that a lowest cost is related to R502 refrigerant and total annual cost for or R134a and R1234ze refrigerants are in the next ranks.