Research On Thermal Storage Cycle Stability Of Binary Eutectic Al-Si Alloy And Surface Treatment To Container

Because the 1980s energy crisis, the basic theory and application of technology of phase change thermal storage had been brought forward brought and continually developed in the developed country. Phase change thermal storage technique can solve the conflict between time and space, therefore, it is an important technique to improve its utilization efficiency and protect environment. Heat energy storage technique is a technique which Phase Change Materials (PCMs) storage energy. It has these virtues, such as: high thermal storage density, isothermal process in melting and freezing and so on. So it's an important way of energy storage. Obviously, PCM is the key of energy storage technique, thus, studying element composition, structure and heat storage property are hinges and bases of heat energy storage technique. The ideal PCM should have high latent heat, appropriate temperature accord with work conditions, better heat storage property and property stability after repeating melting and freezing.The melting temperatures of Al-Si alloy is 577℃(±1℃) , and the latent heats of Al-Si alloy is about 500 kJ/kg, Ai-Si alloy has these characteristics: high latent heat ,High-grade heat of storages, high thermal efficiency, big heat storage coefficient and moderate prices. In the field of middle-high temperature energy storage Al-Si alloy has great prospects for development.One necessarily property of middle and high temperature PCMs was excellent performance of high temperature resistance oxidation. The oxidation behavior of eutectic Al-Si alloy were studied in air in box electric furnace. After 600 hours, Al-Si alloy added weight 3.05mg per square centimeter at 600℃, and the weight of sample increase steadily and slowly.Accelerated thrmal cycle tests have been conducted to study the changes in melting temperatures (T_m) and the latent heats of fusion (ΔH_m) of eutectic Al-Si alloy as PCMs after repeated numbers of melt/freeze cycles in home-made thermal cycling furnace. Experimental results show that its melting point increased 2.4℃, the latent heats reduced 23.4KJ/Kg. There might appear liquid phase in phase change of metal PCM and it has some flow property, so it must be loaded in the container, container must be inert and do not react with Al-Si alloy to product low-melting-point alloy, it must be airproofed. All of these measures avoid liquid leak, otherwise, that would cause people hurt and environment pollution.The experimental study of Al-Si alloy rovide necessary experiment data and theory support for its application in the field of phase change energy storage.