A multiparameter thermal conductivity equation for R134a with an optimized functional form

A new multiparameter equation λ = λ(T, ρ) for the thermal conductivity of R134a has been developed from the available experimental data using a technique for the optimization of the functional form. The equation is valid in the temperature range from 200 to 540 K and for pressure up to 70 MPa, including also the near-critical region. The satisfactory performances of the equation are summarized by an average absolute deviation of 2.04% for the selected 5102 primary data points, with a significant improvement with respect to the present reference equation from the literature. The conversion of the independent variables of the experimental data into those of the equation, i.e. (T, P) into (T, ρ), is performed with a high accuracy equation of state for the fluid.