Numerical Simulation of Heat Charging Process for Solar Heating Units with Metal Phase Change Thermal Storage

Phase change thermal storage is an important mode of solar thermal energy storage. In the paper, the heat charging processes of solar heating units were simulated under three kinds of heat flux (400,600 and 800kW/m2) at the bottom face respectively. Al-Si alloy was selected as phase change materials used in the cylindrical body of the units which were in 3 sizes with the length to diameter ratio of 1 and 2. The change of temperature and solid-liquid phase change interface of Al-Si alloy were analyzed to find out the suitable structure of thermal energy storage units which can run safety under the condition of temperature 700~910K and heat flux 400~ 800kW/m2, such as the application of solar thermal energy storage unit in high temperature solar thermal power stations.