Phase Change Thermal Energy Storage Materials Hydrated Salt Determination Of Thermal Conductivity,

The research here and overseas on the phase change materials for thermal energy storage is introduced. The principles and several methods usually applied for thermal conductivity measurement are described. The construction of the apparatus, equipped with a thermistor, used in the study is described in detail. Basically, the method is a transient method. This method is proved to be accurate, easy and quick operation. It can be applied in both liquid and solid having low melting point. The thermal conductivities for ten salt hydrates in temperature range from 100C to 800C are measured successfully first time with the apparatus. The difficulty due to the existence of the convection and the heat radiation in the solutions was solved. In the experiment, the apparatus was calibrated using four reference substances whose thermal conductivities are known. The relative deviations of the reference thermal conductivities were evaluated to be ? 2.0%. The thermal conductivities of 10 salt hydrates at 5K intervals and the temperatures of fusion are reported in the experimental results. In the results, the measured temperatures of fusion agreed with the literature values on whole. The experimental precision and accuracy of the thermal conductivities obtained in this study are discussed. The results are satisfactory. Salt hydrates are very suitable materials for thermal energy storage under lOOt with respect to the high heat value of fusion and the low cost of the materials. The thermal conductivity of materials for thermal storage is one of the critical thermal data for application. The thermal conductivities of the salt hydrates we measured can be applied in the temperature range from 100C to 800C.