Organic and Inorganic Phase Change Materials in Thermal Energy Storage: A Review on Materials Perspectives and Insights with a Case Study

Abstract

Phase change materials (PCMs) are a significant class of contemporary materials that notably contribute to the effective use of solar energy and waste heat conversion and storage. PCMs are mainly utilized to collect thermal energy through phase transition of materials as latent heat. A high energy storage via latent heat capacity (i.e., accumulation and release thermal energy) in a narrow temperature variation is more efficient than many commonly used heat storage method. Throughout the technical development of PCMs, a wide range of materials have been investigated, including organic and inorganic PCMs. Organic PCMs include paraffin, fatty acids, and polymeric, while inorganic PCMs comprised of salts, salt hydrates, and their mixtures. In this comprehensive review, all classes of PCMs are studied with an emphasis on their thermophysical properties, thermal stability, chemical stability, and methodologies for further development of these energy materials. Overall, this review article presents recommendations for mapping suitable PCMs for thermal storage applications. To conclude, inorganic salts and eutectic mixtures of salts such as chlorides were reviewed and considered most appropriate for thermal energy storage (TES) applications operating at high temperatures. Inorganic salts have attracted increasing amounts of scientific interest due to their promising contribution of economic value in the sustainable and renewable environment.