Spectrally Selective Inorganic-Based Multilayer Emitter for Daytime Radiative Cooling

Dongwoo Chae, Mingeon Kim, Pil Hoon Jung, Soomin Son, Junyong Seo, Yuting Liu, Bong Jae Lee, Heon Lee

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Daytime radiative coolers are used to pump excess heat from a target object into a cold exterior space without energy consumption. Radiative coolers have become attractive cooling options. In this study, a daytime radiative cooler was designed to have a selective emissive property of electromagnetic waves in the atmospheric transparency window of 8-13 μm and preserve low solar absorption for enhancing radiative cooling performance. The proposed daytime radiative cooler has a simple multilayer structure of inorganic materials, namely, Al2O3, Si3N4, and SiO2, and exhibits high emission in the 8-13 μm region. Through a particle swarm optimization method, which is based on an evolutionary algorithm, the stacking sequence and thickness of each layer were optimized to maximize emissions in the 8-13 μm region and minimize the cooling temperature. The average value of emissivity of the fabricated inorganic radiative cooler in the 8-13 μm range was 87%, and its average absorptivity in the solar spectral region (0.3-2.5 μm) was 5.2%. The fabricated inorganic radiative cooler was experimentally applied for daytime radiative cooling. The inorganic radiative cooler can reduce the temperature by up to 8.2 °C compared to the inner ambient temperature during the daytime under direct sunlight.

Original languageEnglish
Pages (from-to)8073-8081
Number of pages9
JournalACS Applied Materials and Interfaces
Volume12
Issue number7
DOIs
Publication statusPublished - 2020 Feb 19

Keywords

  • atmospheric transparency window
  • daytime radiative cooling
  • inorganic radiative cooler
  • one dimensional matrix formulation
  • outdoor subambient cooling
  • particle swarm optimization

ASJC Scopus subject areas

  • Materials Science(all)

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