Low-cost and transparent cooling films with solar-selective nanoparticles for reducing the energy consumption of buildings†

Abstract

As a passive cooling technology with zero energy consumption and pollution, radiative cooling has shown huge energy saving potential. However, its application in building glass still faces great challenges due to the contradiction between transparency and cooling performance. In this work, we combined solar regulation and radiative cooling to develop promising solar selective films. Spectral analysis shows that the solar selective films presented an emissivity of 92.2% in the mid infrared band (8–13 μm), a blocking rate of 78% in the near-infrared band (780–2000 nm), and an average transmittance of 63.7% in the visible band (400–780 nm), resulting in a considerable indoor temperature drop of 11 °C in summer. Meanwhile, energy consumption analysis demonstrated that the solar selective films can reduce the energy consumption of air-conditioning by 11.5–25% in different regions and the corresponding payback periods are only 0.16–0.72 years. More strikingly, the developed films presented a facile preparation process and superior stability, indicating their great application potential in reducing the energy consumption of buildings.