Simulations of air-blown thermal storage in a rock bed

This paper presents computer simulations of air-blown thermal storage in a loosely packed bed of rocks. An important application is storage of solar thermal energy for power generation or process heating. A new formulation is developed for one-dimensional flow of air through the rock bed, including the variation of density with temperature. The model equations are solved numerically and results given for the effect of important parameters such as particle size, depth of bed and air flow-rate. It is shown to be useful for the rock bed to be charged with downwards airflow and discharged with upwards airflow. This schedule is always superior – sometimes significantly so – to a schedule in which the bed is charged and discharged in the same (upwards) direction.

► We simulate air-blown thermal storage in a rock bed using a new methodology.
► Applications include solar power generation.
► A 2-way storage schedule is shown to be always superior to a 1-way schedule.
► Sensitivity to flowrate, depth of bed, particle size is explored.