Experimentation for the evaluation of aluminum foams for improving heat transfer in PCM thermal storages.

The latent heat absorption phenomenon associated with melting of a suitable Phase Change Material (PCM) can be an effective way to improve Thermal Energy Storage (TES) behaviour in many applications. However the most suitable PCMs to be used in HVAC systems find intrinsic limitations due to poor heat transfer capability. This work investigates the use of Aluminum foams as heat transfer medium to improve the overall heat transfer of paraffin waxes that can be possible PCMs to be implemented in hybrid sensible-latent water TESs. The design of a new experimental testing rig is here presented together with some preliminary simulation results obtained during the phase change process of paraffin waxes with melting temperatures around 45 °C, with and without metal foams, in a water thermal storage unit. The simulation results are presented in terms of loading and unloading times of the PCM with and without Al-foam so as to assess the effects of the porous medium on the overall heat transfer performance.