The Application Research For Substitude Refrigerant R407C In A Chilled-Water-Plant

Measures for the protection of the stratospheric ozone layer have led to the phase-out of all chlorinated compounds including hydrochlorofluorocarbons (HCFCs).Chlorine-free compounds, such as hydrofluorocarbons (HFCs) and their mixtures, have been proposed as substitutes for HCFCs.R22 has been widely replaced by zeotropic refrigerant mixtures like R407C.The special thermal characteristics of R407C are studied and a vapor compressing refrigerating plant using R407C is simulated in this paper.(1) To get detailed thermal parameters of R407C, programs based on the famous RKS equation are made. The programs can exactly calculate the parameters such as saturation temperature and pressure, enthalpy ,entropy ,specific volume, etc.(2) Thermal models of condenser, evaporator, compressor, expansion valve and the whole plant are developed in this paper. Simulation calculations are completed and some important operating parameters ,such as condensing pressure, evaporating pressure ,inlet and outlet conditions of compressor are confirmed.(3) As the phenomenon of concentration shift would occur in the refrigerating plant, the quantities and the concentrations of the three components of the refrigerant are calculated in this paper. The concept of void fraction is introduced when calculations in the evaporator are made. A newly developed model is built to calculate the conditions in the condenser. Quantities and concentrations of the refrigerant in other parts of the plant are estimated. At last, the circulation concentrations are calculated.Some new ideas in the areas of calculations of thermal parameters of the mixture refrigerant and circulation concentrations in the refrigerating plant using R407C are proposed in this paper.