Abstract Radiative cooling is an energy-saving cooling technology and is achieved when the grating structure emits infrared radiant heat energy into outer space through an atmospheric window (8 ∼ 13 μ m ). The radiation cooling effect is low for the simple grating structure due to its low absorptivity, thus was a novel multilayered composite grating structure proposed in the paper, an aluminum substrate composite whose top layer is polycarbonate coating and intermediate layers are composed of SrTiO2, SiO and Al2O3. The influencing factors of the absorptivity of the simple grating structure were analyzed by rigorous coupled wave analysis (RCWA), which consider grating period (1 ∼ 5 μ m ), grating height (1 ∼ 20 μ m ), duty cycle (0.75 ∼ 1) and angle of incidence (0 ∼ 75°), it was found that grating height is the crucial factor and increasing grating height can improve the absorptivity of the grating structure Hence, the proposed composite grating structure was studied with 20 μ m grating height and 0.5 to 2 μ m thickness of the polycarbonate (PC) coating, 1 μ m thickness polycarbonate structure was found to have good absorptivity, most is over 0.9, and the net cooling power of this grating structure could reach 71.39 W/m2 at ambient temperature.

中文翻译：

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阳光下多层周期光栅的辐射冷却

摘要 辐射冷却是一种节能冷却技术，是光栅结构通过大气窗口（8 ∼ 13 μm ）向外空间发射红外辐射热能而实现的。简单的光栅结构由于其吸收率低，辐射冷却效果低，因此本文提出了一种新型的多层复合光栅结构，一种铝基复合材料，顶层为聚碳酸酯涂层，中间层由 SrTiO2、SiO2 和氧化铝。通过严格耦合波分析(RCWA)分析了简单光栅结构吸收率的影响因素，考虑了光栅周期(1 ∼ 5 μ m )、光栅高度(1 ∼ 20 μ m )、占空比(0.75 ∼ 1 ) 和入射角 (0 ∼ 75°)，