Almost heat-amount of low temperature (less than 100 °C as hot spring heat and factory-waste-heat) heat-source has been thrown away without using. It is expected that effective utilizing of these heat-sources that have a large quantity of heat. The purpose of this research is phase change characteristic evaluation of the nanosuspension type latent heat storage material. Tetracosane (CH₃(CH₂)₂₂CH₃=338.66, purity>99%, melting point 50.0~53.0°C) is used for dispersion material as a latent heat storage material of nanosuspension. The nanosuspension consists of tetracosane as the dispersed latent heat storage material, the distilled water and the non-ion surfactant. The latent heat storage material is dispersed averaged diameter about 250 nanometers in continuous water phase by an ultrasonic homogenizer. This paper deals with the phase change characteristics that estimated by using differential scanning calorimeter. The heating or cooling rate of DSC and the mass composition ratio of tetracosane are chosen as experimental parameter. The useful thermopysical properties (specific heat, apparent melting or freezing point, latent heat) are obtained.

It is difficult to say that the low temperature heat (50-100 °C, e.g. factory exhaust heat or hot spring) is used effectively at present. Problems in use are unstableness of supply and low temperature, it is desirable to gather up by heat-storage and use it. The purpose of this study is the viscosity evaluation of nanosuspensiton type latent heat storage material. Tetracosane (CH₃(CH₂)₂₂CH₃ = 338.66, purity > 99%, melting point 50.6°C: Ref.) is used for dispersion material as a latent heat storage material of nanosuspension. The nanosuspension consists of tetracosane as the dispersed latent heat storage material, the distilled water and the non-ion surfactant. The latent heat storage material is dispersed averaged diameter about 250 nanometers in continuous water phase by an ultrasonic homogenizer. This paper deals with the viscosity including non-Newtonian characteristics that estimated by using a rotary viscosity meter (ThermoScientific, HAAKE Viscotester550). The measuring ranges are shear rate < 500 1/s and temperature 10-84 °C. Experimental data is adjusted by an exponential law, and useful experimental correlation equations are obtained.

Composite polymer material containing ceramic filler is often used for an electric power device because it has high thermal conductivity and good electric insulation simultaneously. However, the dielectric breakdown voltage of the composite material tends to be lowered by increasing the volume ratio of the ceramic fillers so as to improve the thermal conductivity. Therefore, understanding of the phenomena of dielectric breakdown in the composite material is important to obtain the knowledge for better material design. In this study, the dielectric breakdown voltage of the filler containing composite polymer material was numerically simulated and the obtained results were compared with the data of the sample containing Boron-Nitride and voids (inevitability included during the sample preparation). Microstructure of the composite material was analyzed by SEM and the obtained two dimensional images were used for the numerical simulation of the dielectric breakdown. The dielectric breakdown phenomena of the composite polymer film were successfully performed, and the propagation phenomena of the breakdown in the film thickness direction was simulated. The results showed that the voids in the composite was the initiation point of the breakdown. From the obtained results, it was indicated that the most influential factor of the dielectric breakdown in the used system was the void ratio in the thickness direction.