Passive daytime cooling could contribute to the reduction of our global energy consumption. It is capable of cooling materials down to below ambient temperatures without the necessity of any additional input energy. Yet, current devices and concepts all lack the possibility to switch the cooling properties on and off. Here, we introduce dynamic control for passive radiative cooling during daytime. Using an angle-selective solar filter on top of a nocturnal passive radiator allows tuning the surface temperature of the latter in a wide range by just tilting the filter from normal incidence up to around 23°. This angle-selective filter is based on optically engineered, one-dimensional photonic crystal structures. We use numerical simulations to investigate the feasibility of a switchable low-pass filter/emitter device.

中文翻译：

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基于宽带角度选择性低通滤波器的可调谐日间被动辐射冷却

被动式白天制冷有助于减少我们的全球能源消耗。它能够将材料冷却至低于环境温度，而无需任何额外的输入能量。然而，当前的设备和概念都缺乏打开和关闭冷却特性的可能性。在这里，我们介绍了白天被动辐射冷却的动态控制。在夜间无源辐射器顶部使用角度选择性太阳能滤光片，只需将滤光片从垂直入射角倾斜到大约 23°，就可以在很宽的范围内调节后者的表面温度。这种角度选择滤波器基于光学工程的一维光子晶体结构。我们使用数值模拟来研究可切换低通滤波器/发射器装置的可行性。