Performance optimization and experimental analysis of a novel low-temperature latent heat thermal energy storage device

Abstract

Due to the continuous penetration of renewable energy in the building sector, its instability increases the importance of energy storage in balancing energy demand and supply. However, the low thermal conductivity of phase change materials limits its application. This paper proposes a shell-tube latent heat thermal energy storage device with fins to enhance heat transfer. The ANSYS software is used to establish a three-dimensional simulation model of the device, considering of the nature convection. Furthermore, for this study, an experimental platform is built, and the influence of factors on the device during the charging and discharging period is analyzed. Simulation results show that the melting effects of the device vary with the fin and tube pitch; their optimization results are 40 mm and 90 mm, respectively. Experimental results exhibit that the inlet temperature influences the storage effect of the device, but as long as the phase change material is completely melted, pursuing excessively high temperature is not necessary. The same pattern was observed with the flow rate when the heat exchange fluid reached a turbulent state. After optimization, the effective energy release efficiency of the device reaches 77%, and the corresponding inlet temperature, heat storage flow, and heat release flow are 60 °C, 0.144 m3/h, 0.288 m3/h, respectively.