High-performance subambient radiative cooling enabled by optically selective and thermally insulating polyethylene aerogel

• Main Authors: Leroy, A. (Author), Bhatia, Bikramjit S (Author), Kelsall, Colin Clancy (Author), Zhao, Lingling (Author), Zhang, L. (Author), Wang, Evelyn N. (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Mechanical Engineering (Contributor)
• Format: Article
• Language: English
• Published: American Association for the Advancement of Science (AAAS), 2020-03-30T14:32:36Z.
• Subjects: Article
• Online Access: Get fulltext

Recent progress in passive radiative cooling technologies has substantially improved cooling performance under direct sunlight. Yet, experimental demonstrations of daytime radiative cooling still severely underperform in comparison with the theoretical potential due to considerable solar absorption and poor thermal insulation at the emitter. In this work, we developed polyethylene aerogel (PEA)-a solar-reflecting (92.2% solar weighted reflectance at 6 mm thick), infrared-transparent (79.9% transmittance between 8 and 13 mm at 6 mm thick), and low-thermal-conductivity (kPEA = 28 mW/mK) material that can be integrated with existing emitters to address these challenges. Using an experimental setup that includes the custom-fabricated PEA, we demonstrate a daytime ambient temperature cooling power of 96 W/m2 and passive cooling up to 13°C below ambient temperature around solar noon. This work could greatly improve the performance of existing passive radiative coolers for air conditioning and portable refrigeration applications.
United States. Department of Energy. Office of Science. Basic Energy Sciences (award no. DE-FG02-09ER46577)