Metasurfaces for Future Applications to Passive Radiative Cooling

The increasing global demand for cooling solutions due to rising temperatures and rapid urbanization highlights the need for energy-efficient and sustainable technologies. Passive daytime radiative cooling emerges as a transformative approach, utilizing the Earth’s natural thermal radiation to effectively dissipate heat. This thesis explores the critical role of metasurfaces in enhancing Passive radiative cooling efficiency through their unique ability to control spectral selectivity and thermal emission. This research delves deeply into the principles of Passive Radiative Cooling, emphasizing how metasurfaces leverage the atmospheric window (8-13 μm) for selective thermal radiation. Key design strategies that allow metasurfaces to manipulate electromagnetic waves are thoroughly analyzed, highlighting the role of nanostructures in optimizing performance. By controlling the emission properties of materials, metasurfaces enable effective cooling while maintaining high solar reflectance. The thesis also provides a comprehensive review of recent advancements in metasurface technology. Innovations in material selection, photonic crystals, and metamaterials are examined, showcasing how these advances contribute to high solar reflectance and efficient infrared emission. Furthermore, the thesis identifies the practical challenges of implementing metasurfaces, such as durability, scalability, and aesthetic considerations, which are crucial for their broader adoption in sky-cooling systems. In addition to the technical analysis, this thesis assesses the environmental impact of Passive Radiative Cooling (PRC) through the reduction of energy consumption and the mitigation of urban heat islands. Practical implementations of metasurfaces in architecture, agricultural applications, and space technologies are explored, demonstrating their potential to significantly contribute to sustainable cooling solutions. The integration of metasurfaces into existing systems, including renewable energy technologies, is discussed to highlight their versatility and applicability. Finally, the thesis outlines a roadmap for future research and development in this field. By evaluating the current challenges and proposing innovative solutions, this thesis aims to provide a framework for developing scalable, durable, and efficient metasurface-based Passive radiative cooling systems. The findings underscore the transformative potential of metasurfaces in addressing global energy challenges and advancing sustainable cooling technologies.