Recent advances on the applications of phase change materials for solar collectors, practical limitations, and challenges: A critical review

Global warming is the most serious problem humanity faces in the twenty-first century. To avoid additional global warming, the world must transition away from fossil fuels and toward carbon-free energy sources such as solar energy. However, the current generation of solar collectors is incapable of fulfilling the worldwide need for energy supply, and new creative technologies are required to close the gap between solar energy production and demand. Phase change materials (PCM) are among the most effective and active fields of research in terms of long-term heat energy storage and thermal management. Due to their excellent properties, they can be coupled with solar collectors to conserve surplus solar energy and regulate the temperature of photovoltaic solar collectors. However, PCM's actual applications are limited due to their poor thermal conductivity, availability, cost, and various challenges. This review focuses on recent advancements in integrating PCMs into different types of solar collectors. Furthermore, it aims to detail numerous strategies as well as diverse improvement approaches and modifications that have been developed to improve the performance of PCMs incorporated into solar collectors. Finally, based on the thorough results of this analysis, future suggestions have been made to offer the researcher ideas and feasible concepts for future research into PCM/Solar collectors' system development.