Experimental and Numerical Investigation of Stability of Packed Bed Thermal Energy Storage for CSP Power Plant

This paper is focused on experimental and numerical investigation of a dual-media rock bed thermal energy storage. An experimental test loop whose main component is a 1 m diameter and 3 m high storage tank has been built to carefully study the thermal behavior of rock bed thermocline thermal storage. Experimental results show constant outlet temperature during discharge process and confirm that thermocline is suitable for integration in a CSP power plant. The influences of mass flow rate, charge and discharge temperature difference and partial load have been tested without significant effect on dimensionless axial temperature profile. This indicates the robust and controllable nature of dual-media thermocline energy storage. Numerical 3D simulations have been performed using the commercial code Fluent. Results clearly illustrate that the piston-like behavior of thermocline can be strongly degraded by flow non-uniformities. First comparisons with experimental data show global good agreement even if some improvements of the model are needed.