【摘要】 辐射制冷技术通过8～13μm大气透明窗口向外层空间辐射散热，能够零能耗实现制冷效果。但现有被动辐射制冷(PRC)材料面临无机粒子折射率与带隙的矛盾和有机溶剂的大量使用等难题。本研究提出以六方氮化硼(h-BN)作为填料，其高折射率(约2.2)与宽带隙(约5.96 eV)可协同增强太阳反射率从而减少太阳能吸收，同时结合水性聚氨酯(WPU)基体避免有机溶剂的使用。基于COMSOL Multiphysics~?光学模拟，探究了无机粒子形态对光学性能的调控机制。实验制备的WPU/h-BN梯度复合薄膜光学性能优异，拥有高太阳光谱反射率(93.1%)与强中红外发射率(88.2%)。热管理实验结果显示辐射制冷膜可实现日间降温3.4℃,较商用涂层提升1.7℃。EnergyPlus模拟表明，该薄膜应用于建筑围护结构可降低18.5%年度制冷能耗。通过实验揭示了无机粒子的空间分布在光散射调控中的关键作用，为PRC材料设计提供了新范式，并通过环保水性工艺与显著节能效果，推动其在热管理领域的规模化应用。更多还原

【Abstract】 Radiative cooling technology achieves zero-energy cooling by dissipating heat to outer space through the 8-13 μm atmospheric transparency window.However, current passive radiative cooling(PRC)materials suffer from contradictory requirements between inorganic particles’ refractive index/bandgap and excessive organic solvent usage.The hexagonal boron nitride(h-BN)was proposed as the filler material, leveraging its high refractive index(about 2.2)and wide bandgap(about 5.96 eV)to synergistically enhance solar reflectance while minimizing solar absorption.A waterborne polyurethane(WPU)matrix was employed to eliminate organic solvents.The regulation mechanisms of inorganic particle morphologies on optical performances were investigated through COMSOL Multiphysics~? optical simulations.The fabricated WPU/h-BN gradient composite films demonstrate exceptional optical properties, achieving 93.1% solar reflectance and 88.2% mid-infrared emissivity.Thermal management tests reveal the radiative cooling films achieve 3.4 ℃ daytime temperature reduction, surpassing commercial coatings by 1.7 ℃.EnergyPlus simulations indicate 18.5% annual cooling energy savings when the films are applied to building envelopes.The experiments reveal the crucial role of the spatial distribution of inorganic particles in the regulation of light scattering, providing a new paradigm for the design of PRC materials.Moreover, through an environmentally friendly water-based process and significant energy-saving effects, it has promoted the large-scale applications of these materials in the thermal management field.更多还原