Exploring the role of phase change materials in low-temperature solar thermal applications: an extensive overview with challenges and opportunities

Solar energy is widely acknowledged as a renewable and environmentally friendly energy source. Efficient storage of heat energy is a crucial challenge in solar thermal applications. Phase change materials (PCMs) have gained prominence due to their unique ability to store and release thermal energy through phase transition. The advantageous characteristic of PCMs is their low melting point, facilitating efficient heat storage and retrieval through latent heat of vaporization. This comprehensive review focuses on selecting suitable PCMs for diverse applications, considering their melting point and thermal properties. PCMs with high heat capacity and excellent solar radiation absorption are favored in solar applications, especially for systems requiring large thermal energy storage capacities. This review article underscores the importance of PCMs in low-temperature (0-120 °C) solar thermal applications such as solar desalination, solar water heaters, solar cookers, solar dryers, solar air heaters, and solar chimneys, emphasizing their role in practical heat storage and release. By carefully selecting PCMs based on melting point and thermal properties, the performance and efficiency of solar thermal systems can be optimized, contributing to a greener and more sustainable future.