Thermal performance of packed bed heat storage system for solar air heaters

Thermal performance of the packed bed solar heat storage system was studied under varying solar and ambient conditions in different months. The insulated packed bed heat storage unit was filled with 8500 kg rock pebbles. The solar collection and heat retrieval efficiency of heat storage system ranged between 36–51% and 75–77%, respectively. Heat retrieval efficiency of the developed packed bed was found better as compared to the packed bed filled with phase change material (PCM). The experimental values were found in good conformity with predicted values of the packed bed temperature and hot air temperature retrieved from the bed.