Thermo-physical effect of solid filler on the performance of a packed-bed thermal storage

Abstract

This paper attempts to investigate the effect of the diameter of the solid filler and the porosity of the heat transfer fluid on the selection process of suitable material given best performance in terms of storage capacity of thermal energy storages coupled with parabolic trough concentrating solar power plants. In addition, an optimization model is proposed. The model is formulated as a constrained optimization problem to optimally design a rock-bed storage system. The main objective is to determine optimal values of the porosity and the solid filler diameter of appropriate materials maximizing the storage capacity. A comparative study is considered, where the operation of the thermocline storage is simulated taking into account two different materials, the concrete HT and the granite. The results show that the selection of suitable material depends strongly on the porosity and the solid filler diameter.