Ahmad Shakeel, Siddiqui Abdul Rahim, Yang Kaijie, Zhou Ming, Ali Hafiz Muhammad, Hardian Rifan, Szekely Gyorgy, Daniel Dan, Yang Shu, Gan Qiaoqiang
Sustainable Photonics Energy Research Laboratory, Material Science Engineering, Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA.
Adv Mater. 2024 Dec;36(51):e2404037. doi: 10.1002/adma.202404037. Epub 2024 Sep 6.
Radiative cooling significantly lowers condenser temperatures below ambient levels, enabling atmospheric water harvesting (AWH) without additional energy. However, traditional sky-facing condensers have low cooling power density, and water droplets remain pinned on surface, requiring active condensate collection. To overcome these challenges, a lubricated surface (LS) coating-consisting of highly scalable polydimethylsiloxane elastomer lubricated with silicone oil-is introduced on the condenser side in a vertical double-sided architecture. The design not only effectively doubles the local cooling power, but also eliminates contact-line pinning, enabling passive, gravity-driven collection of water. Robust AWH is demonstrated from a 30 × 30 cm sample in outdoor environments (of varying humidity levels and wind speeds in different months) and with no artificial flow of humidified air. In one outdoor test, the passive water collection rate of LS coating reaches 21 g m h double that on superhydrophobic surface, 10 g m h. In indoor testing (20 °C and 80% relative humidity), this system achieves a condensation rate ≈87% of the theoretical limit with up to 90% of the total condensate passively collected. this approach achieves effective AWH in a decentralized approach that removes the need for piping infrastructure and external energy input.
辐射冷却可将冷凝器温度显著降低至环境温度以下，从而无需额外能源即可实现大气水收集（AWH）。然而，传统的面向天空的冷凝器冷却功率密度较低，且水滴会滞留在表面，需要主动收集冷凝水。为克服这些挑战，在垂直双面结构的冷凝器一侧引入了一种润滑表面（LS）涂层，该涂层由用硅油润滑的高度可扩展的聚二甲基硅氧烷弹性体制成。这种设计不仅有效地使局部冷却功率翻倍，还消除了接触线钉扎现象，实现了水的被动重力驱动收集。在室外环境（不同月份湿度水平和风速各异）且无人工加湿空气流动的情况下，通过一个30×30厘米的样本展示了强大的大气水收集能力。在一次室外测试中，LS涂层的被动集水率达到21克/平方米·小时，是超疏水表面10克/平方米·小时的两倍。在室内测试（20°C和80%相对湿度）中，该系统的冷凝率约为理论极限的87%，高达90%的总冷凝水可被动收集。这种方法以分散方式实现了有效的大气水收集，无需管道基础设施和外部能源输入。
