Numerical investigation of sensible thermal energy storage in a packed porous bed

Thermal energy is stored as sensible heat, latent heat or chemical energy in thermal energy storage systems (TES). Energy is stored or extracted by heating or cooling a liquid or a solid without phase changing in a sensible heat storage system. TES in packed beds is used for efficient implementation of concentrated solar power. A sensible TES sysytem consists of packed solid material and fluid in voids. The type of porous medium and porosity are important for these systems. A sensible TES system is numerically investigated in this study. The system has air as heat transfer fluid and solid spheres as thermal storage material. Steel, cordierite and rock spheres are used as solid part of porous medium. These materials are convenient for thermal energy storage at high temperature. The governing equations are solved by using ANSYS fluent software. The local thermal non-equilibrium model is used in the porous medium. The problem is analyzed in transient time. The fluid thermo-physical properties are temperature dependent, the solid's properties assumed as constant. The results showed that the kind of material, the porosity of the packed bed, and the mass flow rate effect on the thermal energy storage and the storage time.