High-performance subambient radiative cooling enabled by optically selective and thermally insulating polyethylene
A Leroy1, B Bhatia1, C C Kelsall1
1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science Advances
|November 7, 2019
Summary
Researchers developed a novel polyethylene aerogel (PEA) material to enhance passive radiative cooling. This innovative material significantly boosts cooling power and achieves substantial sub-ambient temperatures, improving efficiency for air conditioning and refrigeration.
Area of Science:
- Materials Science
- Thermodynamics
- Optics
Background:
- Passive radiative cooling technologies show promise but underperform due to solar absorption and poor thermal insulation.
- Existing daytime radiative cooling systems face limitations hindering their theoretical potential.
Purpose of the Study:
- To develop a novel material for enhancing passive radiative cooling performance.
- To address challenges of solar absorption and thermal insulation in radiative cooling emitters.
Main Methods:
- Fabrication of polyethylene aerogel (PEA) with specific optical and thermal properties.
- Integration of PEA with radiative cooling emitters.
- Experimental demonstration of cooling performance under direct sunlight.
Main Results:
- Developed PEA exhibits high solar reflectance (92.2%) and infrared transparency (79.9%).
- PEA demonstrates low thermal conductivity (28 mW/mK).
- Experimental setup achieved 96 W/m² cooling power and 13°C sub-ambient cooling.
Conclusions:
- Polyethylene aerogel effectively enhances passive radiative cooling performance.
- The developed material addresses key limitations of existing radiative cooling technologies.
- This advancement holds potential for improved air conditioning and portable refrigeration systems.
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