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TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method
Published on: April 26, 2017
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Bilayer-Structured Passive Radiative Cooling Coating with Thin Thickness, Highly Scattering, and Enhanced Thermal
Zhaoshen Yu1,2, Ji Xu2, Nengjie Zhu2
1College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
Summary
This study introduces a thin, bilayer porous coating for passive daytime radiative cooling (PDRC). The novel material achieves efficient energy-free cooling under various temperature conditions, demonstrating practical potential.
Area of Science:
- Materials Science
- Nanotechnology
- Thermal Engineering
Background:
- Passive daytime radiative cooling (PDRC) offers energy-free thermal management.
- Conventional PDRC materials are often too thick for widespread application.
- A need exists for thinner, high-performance PDRC solutions.
Purpose of the Study:
- To develop a novel, thin bilayer porous structure for enhanced PDRC.
- To overcome the limitations of traditional thick PDRC materials.
- To enable PDRC for both below-ambient and above-ambient temperature applications.
Main Methods:
- Synergistic assembly of inorganic dielectric particles via sedimentation and phase separation.
- Fabrication of a bilayer porous structure with optimized optical and thermal properties.
- Characterization of solar reflectance, atmospheric emissivity, thermal conductivity, and thickness.
Main Results:
- Achieved a thin coating (220 ± 15 μm) with high solar reflectance (98.59%) and emissivity (95.15%).
- Demonstrated significant cooling performance: 4.25 °C below-ambient and 15.67 °C above-ambient.
- Exhibited high thermal conductivity (1.203 W·m⁻¹·K⁻¹) and excellent durability.
Conclusions:
- The developed bilayer porous structure offers a viable strategy for high-performance, thin PDRC materials.
- This approach addresses the trade-off between cooling efficiency and material thickness.
- The PDRC coating shows strong potential for real-world energy-free cooling applications.
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