Application of the multi-current transient hot-wire technique for absolute measurements of the thermal conductivity of glycols

Experimental measurements of the thermal conductivity of mono-, di-, tri-, and tetra-ethylene glycol are presented. The experiments were carried out at atmospheric pressure and at temperatures ranging from 25 to 65 degrees C. The multi-current transient hot-wire technique has been used with a platinum wire of 25 mu m diameter; the electrical current varied from 25 to 75 mA. For all studied glycols, it was found that the thermal conductivity increases with temperature and decreases with the glycol molar mass. The random uncertainty of the reported experimental thermal conductivity data is less than 0.9%. The estimated systematic errors affecting the obtained data are at most 2%. The values obtained in this study were compared with previously published results for the four glycols, finding deviations of the order of 2%.