OPTIMIZATION OF THE VARIABLE REFRIGERANT FLOW SYSTEMS BY USE OF GENETIC ALGORITHM AND ENERGY, EXERGY, AND ECONOMIC ANALYSIS FOR THREE COOLANT FLUIDS

Abstract

The current study aimed at investigation of the Variable Refrigerant Flow (VRF). Energy, exergy, and economic model for R11, R22, and R134a refrigerants. The genetic algorithm was used for optimization of the cycle. The objective functions in the current study were the second law efficiency and cooling cost. The cooling cost was a new economic function that was defined in this paper for the first time. Results showed that the highest Coefficient of Performance (COP) and second law’s efficiency as well as the lowest cooling cost and exergy loss belonged to the refrigerant R134a, and second and third to it were R11 and R22. The optimum values of condenser pressure and evaporators 1, 2, and 3 for the refrigerant R134a were 799.7, 706.2, 925.2, and 23122 (kPa), and the mass discharge of the evaporators 1 and 2, was 0.1 and 0.072 (kg/s).