The effect of the inlet temperature of the heat transfer fluid in a rectangular latent heat energy storage

Abstract

Solar energy is available during the day only. The excess heat energy collected during sunshine hours can be stored in the thermal energy storage and it can be reused during off sunshine hours. Latent heat energy storage systems by using phase change materials (PCMs) can be used effectively for storing thermal energy. It has high-energy storage density and the constant temperature storage process. In this paper, the performance of the latent heat storage system and phase change characteristics of PCM inside a rectangular latent heat energy storage unit will be presented. In this study, purified water is used heat transfer fluid (HTF) which is passed through the copper tubes inside the test unit and commercial-grade paraffin wax is used as PCM and indirect contact heat transfer method is used to heat exchange from the HTF to PCM. It was found that the PCM at the upper layer of the test section first melted during the melting process. Moreover, the effects of inlet temperature of HTF on the charging process was investigated. It can be concluded that increasing the inlet temperature of HTF effectively decreases the total charging time of the melting process. The amounts of heat storage for the inlet temperature of HTF 70 °C and 80 °C are 7400 kJ and 6555 kJ respectively during the melting process.