An Estimation Method for the Thermal Conductivity of the Refrigerants in the Liquid State

An estimation method is proposed for the thermal conductivity estimation of the refrigerant fluids in the liquid state along or near the saturation line.The proposed equation is empirical in nature and provides the thermal conductivity as function of the reduced temperature in the range 0.3 to 0.9, that is from near the normal freezing point to near the critical temperature.The equation contains three parameters: A, a and b; A is a factor depending on the particular compound and it is measured in [Watt/(mK)] as the thermal conductivity, a is an exponent equal to 0.40, a value characteristic of the investigated families (methane and ethane series) and b is the "golden ratio" (1+ 5 )/2 1.618034…a value which appears to be characteristic of the liquid state.The 29 investigated refrigerant fluids show mean and maximum absolute deviations between calculated and experimental thermal conductivity values usually less than 4% and 8% respectively.Other 7 refrigerant fluids are investigated for which reliable data of and of the critical temperature are not not available with acceptable accuracy.