Cooling systems consume 15% of electricity generated globally and account for 10% of global greenhouse gas emissions. With demand for cooling expected to grow tenfold by 2050, improving the efficiency of cooling systems is a critical part of the twenty-first-century energy challenge. Building upon recent demonstrations of daytime radiative sky cooling, here we demonstrate fluid cooling panels that harness radiative sky cooling to cool fluids below the air temperature with zero evaporative losses, and use almost no electricity. Over three days of testing, we show that the panels cool water up to 5 ^∘C below the ambient air temperature at water flow rates of 0.2 l min⁻¹ m⁻², corresponding to an effective heat rejection flux of up to 70 W m⁻². We further show through modelling that, when integrated on the condenser side of the cooling system of a two-storey office building in a hot dry climate (Las Vegas, USA), electricity consumption for cooling during the summer could be reduced by 21% (14.3 MWh).

冷却系统消耗了全球发电量的15％，占全球温室气体排放量的10％。预计到2050年，冷却需求将增长十倍，提高冷却系统的效率是21世纪能源挑战的关键部分。在最近的白天辐射式天空冷却示范的基础上，我们展示了利用辐射式天空冷却技术将流体冷却到低于空气温度且蒸发损失为零的流体冷却面板，并且几乎不使用电力。以上测试的三天，我们表明，板冷却水达5  ^∘以0.2L min的水流速下面C周围空气温度^-1 米^-2，对应于向上的有效排热通量70W的米⁻²。我们通过模型进一步表明，在炎热干燥的气候下（美国拉斯维加斯），将其集成到两层办公楼冷却系统的冷凝器侧时，夏季的冷却用电量可减少21％（ 14.3兆瓦时）。