Abstract

Concentrating solar power (CSP) plants are seen as a key technology to achieve the needed energy transition since its use together with a thermal energy storage (TES) system ensures electricity dispatchability decreasing CSP plants environmental impact and life cycle costs. Latent TES using phase change materials (PCMs) has risen as a very interesting storage technology for such applications. Nevertheless, the selection of the adequate TES system and PCM, is one of the problems researchers and practitioners face to implement such technology. This paper presents a full characterization of fifteen PCMs suitable to work in the temperature range 400-600 degrees C. Melting temperature, melting enthalpy, degradation temperature, and solid-state thermal conductivity are presented, complemented with corrosion behaviour tests against stainless steel and Alloy 20. Moreover, the findings obtained in the characterization of the selected fifteen PCMs highlight the need of these analyses, as notable differences were observed compared to the available data, particularly in thermal stability and thermal conductivity. Furthermore, the compatibility test reveals that out of the fifteen selected PCMs, only two PCMs (binary mixtures of carbonates) are potentially compatible with stainless-steel 314 and Alloy 20 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.