Thermal Conductivity and Melting Point Measurements on Paraffin- Zeolite Mixtures

This paper presents measurements of the thermal conductivity of paraffins mixtured with zeolites of the type 5A and 13X. Because of their high enthalpy change at the phase transition paraffins are able to store more thermal energy at nearly isothermal conditions than sensible heat materials. The poor thermal conductivity of paraffins is a disadvantage, however. The zeolite provides a structure to support the solid and liquid paraffin and to enhance the thermal conductivity. The thermal conductivity of the mixture is increased by a factor of about 1.8 in dependence on the paraffin zeolite ratio. The determination of the thermal conductivity was performed with a heat flow meter apparatus on sample disks with a diameter of 85 mm. Also the laser flash method combined with the measurements of the mass density and the specific heat capacity was used to gain comparative data.