Numerical study of a Phase Change Material (PCM) embedded solar thermal energy operated cool store: A feasibility study

Abstract

Solar energy has proved to be an ideal alternative for fossil fuels, however, due to its intermittency in availability, systems operated by solar energy face serious limitations. In this study, a simplified dynamic model is developed to investigate the behavior of a PCM-embedded cool store. The main application of this type of cool store is to be operated with a solar thermal refrigeration system to compensate for the intermittency in energy availability. 8640 kg of crops (potatoes) is considered to be stored inside the cool store along with PCM cold thermal energy storage units. 9 h of active and 15 h of inactive period are considered for 24 h operation of the refrigeration system based on the solar energy availability data. During the active period, PCM units charge, and during the inactive period, they discharge and regulate the temperature inside the cool store. It was revealed that by choosing the right properties, PCM can keep the temperature of the crops in the desired range during the inactive period of the refrigeration system. Also, it was observed that the amount of PCM used and the phase change temperature of the PCM has a significant impact on the performance of the system. The lowest temperature obtained for the crops during the inactive period of the refrigeration system is for the case with PCM to crops amount ratio of 0.026 with PCM phase change temperature of 9 °C in which the discharge process finishes around the end of the inactive period of the refrigeration.