Engineering-Oriented Framework for Efficient Sensible Heat Storage Material Screening in Packed-Bed TES Systems

Packed-bed thermal energy storage (TES) offers a promising solution for large-scale, high-temperature sensible-heat applications. However, the pre-selection of storage materials remains a persistent challenge, owing to the wide diversity of candidate solids and the computational intensity of detailed simulations. In this study, a simplified, physics-informed framework was developed for engineering-oriented screening of sensible-heat storage materials in packed-bed TES systems. An application-driven performance metric— q v ,ave , the average volumetric heat-transfer rate per unit temperature difference—is introduced. The analysis revealed that enhancing the thermal conductivity ( λ s ) of the storage material improves q v ,ave , but only up to a distinct critical threshold. Beyond this critical λ s value, further thermal conductivity enhancement yields diminishing returns with negligible improvement in q v ,ave . This crucial observation underpins the development of a practical engineering matching diagram, which delineates the optimal (or necessary) λ s ranges for storage materials compatible with different heat transfer fluids. Additionally, to further enhance the heat transfer performance of the sensible heat storage sphere while accounting for the pressure drop and practical constraints, a three-step engineering selection framework was proposed. This framework integrates the application requirement definition, candidate material screening (leveraging the matching diagram), and particle size design, thereby facilitating rapid and efficient material selection for packed-bed TES engineering applications.