Extreme urban heat causes serious climatic, environmental, and economic problems. Daytime radiative cooling technologies are the most promising cooling technology in recent years. Here, we report experimental and numerical analysis to assess the cooling performance of scalable broadband radiative coolers, evaluate their heat mitigation potential in cities, and investigate their impact on local climate and the atmospheric dynamics. We show that, when air temperature reached its peak, the sub-ambient surface temperature of 8.2°C was achievable for samples with a wind cover. The maximum reductions of peak ambient temperature, average daytime ambient temperature, and highest urban canopy temperature are 5.3°C, 3.6°C, and 13°C, respectively. Collectively, we show that broadband coolers can significantly mitigate urban heat, but the cooling island effect they generate would increase side effects such as a decrease in the mixing layer of the atmosphere and an increase in pollutant concentration.

城市极端高温会导致严重的气候、环境和经济问题。日间辐射冷却技术是近年来最具发展前景的冷却技术。在这里，我们报告了实验和数值分析，以评估可扩展宽带辐射冷却器的冷却性能，评估它们在城市中的散热潜力，并研究它们对当地气候和大气动力学的影响。我们表明，当空气温度达到峰值时，带有风罩的样品可以达到 8.2°C 的低于环境表面温度。最高环境温度、平均白天环境温度和最高城市冠层温度的最大降幅分别为 5.3°C、3.6°C 和 13°C。总的来说，我们表明宽带冷却器可以显着减轻城市热量，