Scalable, Recyclable, and Sustainable Daytime Radiative Cooling Materials Engineered by Cellulose-Based...

Area of Science:

• Materials Science
• Nanotechnology
• Sustainable Energy

Background:

• Passive daytime radiative cooling (PDRC) is a zero-energy technology for reducing temperatures under sunlight.
• Single-component cooling materials face limitations due to fixed properties, restricting performance under intense solar irradiance.

Purpose of the Study:

• To develop a composite material with enhanced broadband solar reflectance and mid-infrared emissivity for improved PDRC performance.
• To overcome the intrinsic limitations of single-component cooling materials.

Main Methods:

• Fabrication of a hybrid binary-particles cellulose acetate material (BCA) using BaSO4 and Al2O3 particles.
• Characterization of solar reflectance and mid-infrared emissivity.
• Experimental validation of cooling performance under simulated solar irradiance and outdoor conditions.

Main Results:

• The BCA composite achieved 96.0% broadband solar reflectance and 95.2% mid-infrared emissivity.
• Demonstrated subambient cooling of 5.5 °C under 1000 W·m⁻² solar irradiance.
• Reduced surface temperatures by over 13 °C on car exteriors, with potential energy savings > 138 kWh·m⁻² for buildings.

Conclusions:

• The developed BCA material shows significant potential for practical PDRC applications due to its high performance.
• The material exhibits favorable cost, scalability, and recyclability, supporting large-scale implementation.
• This composite approach offers a pathway to overcome limitations of single-component PDRC materials.