Hierarchically structured passive radiative cooling ceramic with high solar reflectivity

Area of Science:

• Materials Science
• Nanotechnology
• Thermodynamics

Background:

• Passive radiative cooling technologies face limitations in cost, compatibility, weather resistance, and solar reflection.
• Existing nanophotonic structures are expensive and difficult to integrate, while polymeric alternatives degrade and reflect poorly.

Purpose of the Study:

• To develop a novel passive radiative cooling material with enhanced performance and durability.
• To overcome the limitations of current radiative cooling technologies for practical applications.

Main Methods:

• Development of a cellular ceramic structure engineered for high light scattering.
• Characterization of the ceramic's solar reflectivity, thermal emissivity, and cooling performance.
• Evaluation of material properties including color, weather resistance, mechanical robustness, and Leidenfrost effect suppression.

Main Results:

• The developed cellular ceramic exhibits near-perfect solar reflectivity (99.6%) and high thermal emissivity.
• Achieved continuous subambient cooling with a cooling power exceeding 130 W/m² under direct sunlight.
• Demonstrated excellent weather resistance, mechanical robustness, and suppressed the Leidenfrost effect.

Conclusions:

• The cellular ceramic offers a durable and versatile solution for passive radiative cooling.
• The material's performance and properties facilitate commercialization, particularly for building construction.
• This technology presents significant global energy-saving potential through efficient cooling solutions.