Thermo-mechanics in packed beds: Modeling and design of high temperature heat storage

Abstract

Several novel power plant technologies, such as concentrating solar power (CSP) plants or adiabatic compressed air storage (ACAES), depend on heat storage systems as a central plant element. Where gaseous heat transfer media at elevated temperature levels are used, a regenerator-type heat storage is a particularly cost-effective solution. A large-scale design based on a packed bed inventory can further reduce investment costs, but is fraught with the risk of mechanical failures caused by the punctiform particle contacts. To be able to reduce such risks in a careful design, a simulation tool has been developed and successfully validated. It allows to predict the thermally induced mechanical loads during charge and discharge operation. As a calculation result, the model provides the time varying forces and displacements for each individual particle. The present paper outlines the underlying model equations and, by means of an illustrative example application, summarises the characteristic behaviour of such a setup.