The latent heat storage (LHS) is an promising method for storing thermal energy, where a phase-change material (PCM) stores or releases latent heat during a phase transition. This work presents a study on metallic PCMs properties for heat storage between 550 °C and 900 °C. Four PCMs have been selected from literature and CALPHAD calculations using Factsage 8.2 software (SGTE database). The ternary Al-Cu-Si diagram is covered by the selected points of interest, such as 88Al-12Si (%wt), 84Cu-16Si (%wt), 25Al-68Cu-7Si (%wt) and 4Al-84Cu-12Si (%wt).

The PCMs were synthetized with a high-frequency induction furnace under vacuum. The alloys were analysed by different techniques: DSC (STA 449 F3 Netzsch), pycnometry (Accupyc 1340 Micromeritics), XRD (D8 Bruker), SEM (LÉO 1530 VP Gemini), TMA (Setsys Evo Setaram). Several thermophysical properties of the materials have been measured to put into evidence the effect of the composition on the intrinsic and usage properties. These measured values are compared to the predicted ones and some previous work. While increasing the latent heat of fusion of alloys by interchanging Cu by Al, the density drops and the effect on the thermomechanical properties is underlined.

This research is part of a large European project, HEATERNAL, which its main ambition is to meet the industry needs of a constant high temperature (HT) heat in the face of climate and geopolitical urgencies. This document has been prepared within the framework of IEA ES TCP and has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101103921, HEATERNAL.