Mixing rules for the specific heat capacities of several HFC-mixtures

The specific heat capacity at constant pressure (c(p)) of some relevant HFCs as replacements for R12, R502 and R22 was measured. The liquids investigated are binary or ternary mixtures of R134a, R152a, R125, R32 and R143a. Empirical functional relations in polynomial forms between the temperature, specific heat capacity and concentration are established and the coefficients of the polynomial correlations are presented. These equations can be used to calculate the c(p)-values for the mixtures investigated over the whole concentration range and the predicted 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 degrees C. (C) 1997 Elsevier Science Ltd and IIR.