Daytime radiative cooling with clear epoxy resin

Radiative cooling (RC) technology without any energy input and any pollution produced has drawn intensive research efforts. However, the high cost and poor performance of RC materials seriously impeded the development of this cooling technology. Here, a facile and cost-effective RC material was proposed to achieve daytime cooling performance. The spectral profile revealed that the weighted average solar reflectivity and infrared emissivity in the atmospheric window reached 93% and 92%, respectively. And the proposed RC material can achieve sub-ambient cooling performance, even in high temperature and humidity areas, with an average maximum temperature drop (MTD) of about 2.75 °C in the daytime (10–14 o'clock) and an average MTD of about 8.1 °C at night. Further experiments with Nano PE wind cover indicated that the RC performance was boosted remarkably, with an average MTD of about 4.1 °C in the daytime. Additionally, the back-to-sun tilt strategy further improved the material's cooling performance, with a daytime MTD of about 5 °C. More intriguingly, the discussion on cooling potential demonstrated that the RC material was more competitive in arid areas and above-ambient RC fields. Our work opens up a new avenue for the application of facile and cost-effective RC materials.