Experimental characterization of phase change materials for thermal energy storage in the temperature range between 270 °C and 400 °C

Thermal energy storage (TES) with phase change materials (PCM) is an interesting technology to be used to improve the energy efficiency of industrial processes, contributing to their decarbonization and the integration of renewable energy sources. Even though literature lists many materials that can be used as PCM in the temperature range between 270 °C and 400 °C, most of them lack a full characterisation, jeopardising their potential implementation by practitioners and scientists. Therefore, this paper presents a complete experimental characterisation of 24 PCMs, with melting temperature, melting enthalpy, degradation temperature, and thermal conductivity in the solid state (at room temperature) determination. Moreover, corrosion tests with two different stainless-steel fibres and with Alloy 20 fibres is presented. The findings obtained in the characterization highlight the necessity of these analyses, as notable differences were observed compared to the available data, particularly in thermal stability and thermal conductivity. Moreover, the findings obtained in the compatibility test reveals that out of the 24 selected PCMs, 11 are potentially compatible with Alloy 20, and 8 with both stainless-steel fibres under environmental conditions (air atmosphere). Finally, the results presented will allow researchers and practitioners to have very detailed data on the characterisation of those PCMs.