An investigation of the thermal transport properties of octadecane, a material used in thermal energy strorage systems

An investigation of the thermal transport properties of solid octadecane is presented. A literature search revealed that few data concerning those properties have been published, and that those that have been published were not consistent. An experimental program was developed to determine the value of the material's thermal properties and to find an explanation for the inconsistencies in the published data. The program included three different types of experiments; a freezing experiment which produced the ratio of the thermal conductivity to the product of latent heat and density, a conduction experiment which produced values of thermal diffusivity, and a series of "line source" measurements of thermal conductivity. The results indicated that, for the sample used, the thermal properties did indeed vary in a systematic way, and that the results depended on sample preparation and the method of measurement.

The probable causes of the variations in the reported data are shown to be failures to account for (1) voids which form in the solid and (2) natural convection in the liquid during freezing.