MIXING RULES FOR THE SPECIFIC-HEAT CAPACITIES OF SEVERAL HFC-MIXTURES

The specific heat capacity at constant pressure (c(p)) of some relevan t HFCs as replacements for R12, R502 and R22 was measured. The liquids investigated are binary or ternary mixtures of R134a, R152a, R125, R3 2 and R143a. Empirical functional relations in polynomial forms betwee n the temperature, specific heat capacity and concentration are establ ished and the coefficients of the polynomial correlations are presente d. These equations can be used to calculate the c(p)-values for the mi xtures investigated over the whole concentration range and the predict ed properties generally agree with the source data to ca +/- 0.1% for the pure substances. The accuracy of the measurements is better than < 1% for the pure fluids and <1.5% for the mixtures. Differences between 1 and 2% can occur only at temperatures >40 degrees C and <-50 degree s C. (C) 1997 Elsevier Science Ltd and IIR.