Sub-ambient radiative cooling under tropical climate using highly reflective polymeric coating

Di Han, Jipeng Fei, Jyotirmoy Mandal, Zhixin Liu, Hong Li, Aaswath P. Raman, Bing Feng Ng

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

While passive radiative cooling has shown great potential in temperate regions in lowering surface temperatures, its cooling performance under tropical climate that is characterised by high solar irradiance and humidity still lacks exploration. Herein, we adopt a highly reflective polymeric coating with BaSO4 particles dispersed in P(VdF-HFP) matrix for radiative cooling in the tropics. Through the strong Mie scattering of sunlight and intrinsic bond vibration, the substrate-independent average solar reflectance and infrared emittance within the 8–13 μm atmospheric window could reach 97% and 94.2%, respectively. For the first time, surfaces could maintain sub-ambient temperatures under direct exposure to the sky and surroundings even when the solar intensity was 1000 W/m2 and downwelling atmospheric radiation was 480 W/m2, while separately achieving 2 °C below ambient during night-time with an effective cooling power of 54.4 W/m2. With a scalable fabrication-process, our cost-effective single-layer coating can be easily applied to diverse substrates, which is suitable for real-world applications in the tropics.

Original languageEnglish (US)
Article number111723
JournalSolar Energy Materials and Solar Cells
Volume240
DOIs
StatePublished - Jun 15 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films

Keywords

  • Mie scattering
  • Polymeric coating
  • Solar reflectance
  • Sub-ambient radiative cooling
  • Tropical climate

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