Thermal Analysis of Molten Salt Thermocline Thermal Storage System with Packed Phase Change Bed

Energy storage performances of molten salt thermocline thermal storage system with packed phase change bed are numerically studied by using transport model of porous media and phase change model of thermocline bed. The results show that the packed phase change bed can remarkably increase the energy storage density and discharging efficiency. The thermocline with phase change material can be divided into three stages, or high temperature thermocline, low temperature thermocline and phase change layer. As the melting point of phase change material approaches to the outlet temperature, the effective discharging energy remarkably increases, so the optimal melting point should be equal to the outlet temperature for good heat storage performance. As the phase change material content increases, the phase change layer thickness and discharging time increases.