In the realm of high-temperature energy storage, a team of researchers from the Spanish National Research Council (CSIC) and the University of Birmingham has been exploring the potential of Al-Cu-Si alloys as phase change materials (PCMs). This group, led by Laura Teodorescu and including Ángel Serrano, Kyran Williamson, Cristina Luengo, Artem Nikulin, Elena Palomo del Barrio, and Grégory Largiller, has published their findings in the journal Applied Energy.
The team set out to investigate the suitability of Al-Cu-Si ternary alloys for thermal energy storage systems operating between 550°C and 850°C. Previous research in this area has largely focused on thermodynamic modeling or thermal property characterization below 600°C. This study, however, provides a comprehensive experimental assessment of selected invariant compositions within the Al-Cu-Si system.
The researchers began by performing CALPHAD calculations using FactSage 8.2 software to guide their alloy selection. They then synthesized and characterized the alloys, measuring their melting point, latent heat, specific heat, thermal diffusivity, and thermal conductivity. Notably, they also evaluated the thermal reliability of these materials under repeated solid-liquid cycling up to 100 cycles in oxidizing atmospheres. This provided valuable insights into the alloys’ stability and degradation profiles.
The team also conducted dilatometry and density analysis to gain a deeper understanding of the alloys’ practical properties. Their findings revealed that several of the tested alloys demonstrated high volumetric energy densities (over 500 kWh/m³ for a temperature difference of 300°C) and good thermal durability. This suggests that Al-Cu-Si alloys could be promising candidates for industrial-scale high-temperature energy storage applications.
The research fills a significant gap in the literature by combining phase selection, comprehensive thermophysical property evaluation, and long-term cycling analysis above 600°C. The practical applications of this work could be substantial for the energy sector, particularly in industries that require high-temperature energy storage solutions. The full study can be found in the journal Applied Energy, volume 333, published in February 2023.
This article is based on research available at arXiv.