The thermal performance analyses of the solar energy-powered thermal energy storage system with MgCl2·6H2O as PCM

Abstract

This work analyzes the thermal performance of the solar energy-powered thermal energy storage (TES) system with MgCl2·6H2O as a phase change material (PCM). The PCMs are encapsulated in the copper cylindrical containers which have longitudinally extended surfaces on the outer periphery. The encapsulated cylindrical containers are arranged vertically in the TES tank. The experiments are conducted to find the energy gained by the heat transfer fluid (HTF) from the collector and the energy storage capacity in the TES tank during the charging process of PCM. It is seen that the temperature variation of PCM between 8:00 and 9:00 h is very slow due to the low thermal response of the components in the experimental setup. The HTF temperature rise is at a faster rate till 12:00 h due to increase in solar radiation value which is raised from 380 to 930 W m−2. Also, the maximum energy gained by the HTF from the collector is 14,330 kJ at 13:30 h which has 6109 kJ energy difference than the energy accumulation in the TES tank due to the lower thermal behavior of the devices in the system. The maximum efficiency of the collector is 72.53% between 13:00 and 14:00 h, after that the efficiency decreases with the increase in time due to the decrease in the solar intensity value. The performance of the system could be improved by using high-reflective material in the solar collectors and also by the use of higher thermal conductivity heat exchange materials.