Search

This article establishes an experimental platform for study of the thermal storage characteristics of solid thermal storage materials in low pressure environments. The experimental results show that under the influence of the thermal inertia of the heating section in low pressure environments, the thermal storage rates of thermal storage materials first increase to the peak, and then gradually decrease with the increase or decrease of the temperature of the thermal storage bricks. Air pressure has a significant impact on the heat storage rate of thermal bricks: compared to a 101kPa atmospheric pressure environment, under the same heating temperature, the heat storage time of 80kPa and 40kPa is significantly increased, and the lower the air pressure, the longer the heat storage time required.

Thermal storage ceramics using metals as phase change materials (PCMs) have both high thermal conductivity and high heat storage density. However, in the process of use is very easy to occur in the metal phase change material leakage, will seriously affect the service life of the thermal storage ceramics. In this study, ceramic composite phase change heat storage materials with Al-12Si alloy as phase change material were prepared. Firstly, Al-12Si was pretreated by sol-gel method and high temperature heat treatment to obtain the pretreated Al-12Si alloy powder with dense alumina shell layer. Afterthat, the pretreated Al-12Si alloy powder was mixed and pressed with alumina, silicon dioxide, magnesium oxide, and mullite respectively, and sintered at 1,100°C, 1,200°C, or 1,300°C. The experimental results show that the metal phase change materials and the four ceramic materials show good chemical compatibility, and pretreated Al-12Si essentially retains its initial shape and is uniformly dispersed in the heat storage material. Among all the samples, the pre-treated Al-12Si/mullite ceramic thermal storage materials with a sintering temperature of 1,200°C showed the best thermal storage performance. The thermal conductivity of the samples was up to 17.94 W/(m-K). The latent heat storage value was 139.51 J/g before thermal cycling, 138.27 J/g after 100 thermal cycling, which was only decreased by 0.89%, and there was almost no alloy leakage. This study has successfully realized that the ceramic thermal storage material possesses high thermal conductivity, high thermal storage density and excellent thermal cycling performance at the same time, and provides a new method for the production and preparation of Al-12Si/ ceramic heat storage materials, which has great potential for application in heat storage systems. [ABSTRACT FROM AUTHOR]

In this paper, a new molten salt/ceramic composite phase change thermal storage material was prepared by sol-gel method and powder compacting method. The surface of molten salt particles was encapsulated with SiO2 or TiO2 by sol-gel method, then the molten salt particles were combined with MgO to prepare composite phase change thermal storage materials. By this method, the density of the composite increased by 8.74%, the thermal conductivity increased by 16.27%, after high-temperature heat. The decline of the heat loss rate was only 2.67%. [ABSTRACT FROM AUTHOR]