Optimization of thermal energy storage in packed columns

We propose a method for optimizing the net economic income for thermal energy storage in a cylindrical column packed with solid spheres. The economic value of stored heat is maximized relative to equipment and operating costs for air-based solar energy storage systems packed with either rock or steel spheres. Variables optimized separately are bed length and diameter, air flow rate, spherical particle diameter and collection time. Simultaneous optimization of a subset of these variables is illustrated. The mathematical model for the transient temperature profile in the bed includes intraparticle heat conduction, axial dispersion and heat losses to the surroundings, as described in earlier papers.