Solar Adsorption Refrigeration: Materials, Cycles, and System Integration

Solar-driven adsorption refrigeration has emerged as a sustainable alternative to conventional vapor-compression cooling because it can utilize low-grade thermal energy and environmentally benign working fluids. Recent research has focused on improving adsorption materials, optimizing thermodynamic cycle configurations, and integrating systems into buildings and cold-chain applications to enhance overall coefficient of performance (COP), specific cooling power (SCP), and economic feasibility. Studies demonstrate that advanced adsorbents such as silica gel composites, activated carbon, zeolites, and metal–organic frameworks significantly improve adsorption capacity and heat–mass transfer characteristics, thereby enabling higher cooling efficiency under variable solar conditions. In parallel, innovations in cycle design—including multi-bed configurations, heat and mass recovery strategies, and hybrid solar-assisted layouts—have contributed to improved operational stability and reduced energy consumption. System-level investigations further highlight the importance of climatic suitability, thermal storage integration, and techno-economic optimization for real-world deployment in residential buildings and agricultural cold storage. Despite measurable progress, challenges remain in material durability, intermittency of solar input, and large-scale cost competitiveness. This review synthesizes recent advances in working-pair selection, cycle innovation, and integrated system design to provide a consolidated framework for future development of high-performance solar adsorption refrigeration technologies suitable for sustainable cooling and cold-chain preservation.