Thermal performance and optimisation of a granular-bed heat recuperator

Abstract

This paper presents a performance analysis and optimisation of a granular bed heat recuperator for thermal energy storage and recovery. Simulating the flow processes in the bed, the study develops a transient three-dimensional turbulent numerical formulation with non-equilibrium porous medium model, where by thermal and fluid characteristics are appraised and examined. In this, Ergun equation is applied for resistance source terms of momentum while the well-regarded Ranz-Marshal and Wakao models are used for interfacial heat transfer. In ascertaining prediction accuracy, the model is initially validated for flow hydrodynamics against experimental pressure drop data. Transient thermal behaviour is then verified against experimental thermal measurements to achieve the most accurate and robust simulation of thermal and fluid characteristics. The simulation model is applied to establish passive optimisation techniques based on thermal storage saturation for a given granular heat recuperator.