Design and optimization of solid thermal energy storage modules for solar thermal power plant applications

Abstract : Solid sensible heat storage is an attractive option for high-temperature storage applications in terms of investment and maintenance costs. Typical solid thermal energy storage systems use a heat transfer fluid to exchange heat as the fluid flows through a tubular heat exchanger embedded in the solid storage material. The modified lumped capacitance method is used with an effective heat transfer coefficient in a simplified analysis of the heat transfer in solid thermal energy storage systems for a solid cylindrical heat storage unit. The analytical solution was found using the Laplace transform method. The solution was then used to develop an optimization method for designing solid storage modules which uses the system requirements (released energy and fluid outlet temperature) as the constraint conditions and the storage module cost as the objective function for the optimization. Optimized results are then given for many kinds of system configurations.