Investigation of storage rotation effect on phase change material charging process in latent heat thermal energy storage system

Abstract

Applying Phase Change Materials (PCMs) in Thermal Energy Storage (TES) systems is an appropriate method to utilize renewable energies, more efficiently. Due to the low thermal conductivity of the PCMs, the application of active and passive heat transfer enhancement techniques is increasing. In this study, a double-pipe Latent Heat Thermal Energy Storage (LHTES) System in which the annulus is filled with PCM is considered and storage rotation method is suggested as an active heat augmentation technique to accelerate the charging process of the systems. Different scenarios are considered for rotations, including constant speed and step-by-step rotation methods. The charging process of a LHTES system is simulated numerically considering 2-D model, and the effect of different scenarios of the storage rotation is investigated on charging time. The results show that rotating the storage with constant rotational speed has a slight positive effect on complete melting process time (maximum reduction of 3.45%), however 15.5% reduction in charging time can be achieved compared to the fixed mode by applying step-by-step rotation scenario which is related to the case with two opposite direction rotations and 180 angle difference between the stop steps.