This work presents a new simple equation for the thermal conductivity of liquid refrigerants as a function of the reduced temperature, molecular mass, reduced pressure, and the acentric factor. This model is applied for predicting the thermal conductivity of the refrigerants over the whole temperature and pressure ranges. A set of 915 data on the thermal conductivity for 30 refrigerants has been used. These refrigerants were divided into three categories on the basis of various chemical halogens forming the compounds and were investigated individually. For the data sets, the average error of the proposed model was 4.82%. The results show that the new equation can be used with confi dence in engineering calculations.Introduction. Thermal conductivity is evaluated primarily in terms of the Fourier law for heat conduction. It shows the capability of a substance to transfer heat by conduction. In fact, the higher the thermal conductivity, the higher the heat transfer coeffi cient. Knowledge of the thermal conductivity is required in numerous phenomena of scientifi c and practical interest, in particular, for refrigerants, though the values of their thermal conductivity are frequently not attainable with suffi cient reliability and are sometimes even unattainable.For computation of the thermal conductivity of liquids, a number of theories have been presented on the basis of the characteristic properties of materials, such as the heat capacity and/or density [1,2]. There are equations based on the theory of group contribution for calculating the thermal conductivity of liquids, such as those based on the intermolecular distances [3] or on the degree of association of liquids [4]. These equations are very often inappropriate for all compounds. Different correlations for the description of the thermal conductivity are proposed in [5][6][7][8][9][10][11][12][13].In the present research, the thermal conductivity is estimated from an empirical approach based on a number of fi xed physical parameters, and the results are tested on the large database for liquid refrigerants. The new equation is used for refrigerants over the whole ranges of temperatures and pressures, unlike previous equations that were applicable at atmospheric pressure.
Description of the Simple Equation.In this research, an attempt is made to present an approach to calculating the thermal conductivity of refrigerants with a high accuracy over the whole range of temperatures and pressures. A total of 915 experimental points for the proposed correlation has been considered.The proposed equation presents a simple correlation for estimating the thermal conductivity of refrigerants as a function of the reduced pressure, reduced temperature, acentric factor, and the molecular weight. This new equation includes fi ve independent variables A i :