Experimental study of phase change material (PCM) embedded in 3D periodic structures realized via additive manufacturing

The interest in Phase Change Materials (PCMs) has been continuously growing, since they were identified as a suitable way to store large quantities of thermal energy. Despite many PCMs being available on the market, almost all present a relatively low thermal conductivity, which limits the efficiency and the convenience of their use inside Latent Thermal Energy Storage (LTES) units. This paper proposes a novel method to overcome the low thermal conductivity drawback: additive manufacturing was used to realize three innovative 3D metallic periodic structures, with different base pore sizes (10, 20, and 40 mm) and constant porosity, to be filled with a suitable PCM. The samples were experimentally tested by analyzing the temperature field in a paraffin wax, which has a melting temperature of around 55 °C. Furthermore, several videos and images were taken during the charging (i.e. heating and melting) process, obtained by electrical heating (three heat fluxes corresponding to 10, 20, and 30 W were applied) and the discharging (i.e. solidification and cooling) process, where the heat was only rejected by natural convection with ambient still air. The coupling of PCMs and aluminum structures was demonstrated to enhance both the charging and the discharging processes.