Natural and forced convection in high temperature PCM embedded in a 3D periodic structure realized via additive manufacturing

The interest in Phase Change Materials (PCMs) is continuously growing, since they have been identified as a suitable way of storing large quantities of thermal energy. There are many PCMs available on the market, nevertheless almost all present a relatively low thermal conductivity, which limits the efficiency and the convenience of their use inside Latent Thermal Energy Storages (LTES). This work proposes a novel method to overcome the low thermal conductivity drawback, the additive manufacturing was used to realize innovative 3D metallic periodic structures to be filled with a suitable PCM. The samples were experimentally tested by analyzing the temperature field in a paraffin wax having a melting temperature of around 70 °C and by collecting several videos and images during the charging (i.e. heating and melting) process, obtained by electrical heating (power from 30 W to 60 W were applied) and the discharging (i.e. solidification and cooling) one where the heat was rejected by natural or by forced convection with ambient air. The coupling of PCMs and aluminum structures was demonstrated to enhance both the charging and the discharging processes