Advances in nano-enhanced phase change materials and hybrid thermal energy storage systems: Paving the way for sustainable energy solutions

Thermal Energy Storage (TES) systems are integral for alleviating the fluctuations associated with renewable energy sources, thereby facilitating more dependable and efficient energy management strategies. Nevertheless, traditional TES systems are hindered by insufficient thermal conductivity, limited cycling stability, and challenges related to environmental sustainability. This work examines contemporary advancements in TES technologies, with a particular emphasis on nano-enhanced phase change materials (NEPCMs) and hybrid TES systems that amalgamate both sensible and latent heat storage methodologies. The integration of nanoparticles, such as carbon nanotubes, metal oxides, and graphene, into PCMs has resulted in enhancements in thermal conductivity of up to 60%, while concurrently preserving stable performance across more than 2500 cycles. Hybrid TES systems attain energy densities that surpass 350 MJ/m³ and operational efficiencies that exceed 90%, thereby significantly eclipsing traditional storage methodologies. Furthermore, the application of environmentally benign materials, artificial intelligence-driven optimization frameworks, and waste-derived nano-additives bolsters the ecological and economic feasibility of these systems. This work encompasses advancements in nano-encapsulation technologies, machine learning (ML) optimization techniques, and circular economy paradigms to outline a comprehensive trajectory for scalable, low-carbon TES implementation. The incorporation of these innovations addresses crucial technical, economic, and environmental issues, thereby positioning TES systems as essential facilitators for applications including solar thermal power facilities, intelligent grids, and sustainable industrial energy management.