Effect of aspect ratio and dispersed PCM balls on the charging performance of a latent heat thermal storage unit for solar thermal applications

A cylindrical latent heat thermal storage system having a phase change material, HS89, encased in spherical capsules and stacked in rows to form a packed bed phase change material containment was considered for the experimental investigation. The heat is stored at 89 degrees C which is very useful for many process industry applications using solar water heaters. Three different aspect ratios were considered for experimentation. The temperature profiles of the phase change material containment and the heat transfer fluid at various heights were measured and monitored continuously. These temperature values were used to determine the variation in charging efficiency, stratification number and Richardson number of the storage system which are very useful parameters to design a storage system. The results presented in this paper will be very useful to design a phase change material based thermal storage for solar thermal applications. (C) 2019 Elsevier Ltd. All rights reserved.