Dynamic response of a packed bed thermal storage system—a model for solar air heating

A mathematical model for simulating the dynamic temperature response of a packed column to an arbitrary time-dependent inlet air temperature is developed. The model includes axial thermal dispersion as well as intra-particle conduction, features that have usually been neglected but can be important in solar energy applications. Solutions, presented in terms of moments of the temperature response to an impulse of heat at the inlet, can be evaluated by simple numerical quadrature. Results of the model compare favorably with experimental data found in the literature. The model is used to optimize heat storage in a rock bin system subject to a realistic transient inlet temperature.