Dynamically Tunable All-Weather Daytime Cellulose Aerogel Radiative Supercooler for Energy-Saving Building

Area of Science:

• Materials Science
• Nanotechnology
• Sustainable Energy

Background:

• Passive cooling strategies are crucial for reducing global energy consumption.
• Designing tunable daytime radiative coolers for diverse weather conditions, especially hot and humid regions, remains a significant challenge.

Purpose of the Study:

• To develop a novel, tunable, thermally insulating, and compressible cellulose nanocrystal (CNC) aerogel cooler.
• To evaluate the cooling performance of the CNC aerogel in various environmental conditions.
• To assess the potential energy savings of using these aerogel coolers in buildings.

Main Methods:

• Preparation of CNC aerogel coolers using chemical cross-linking and unidirectional freeze casting.
• Tuning cooling performance by controlling the compression ratio of the shape-malleable aerogel.
• Experimental testing under direct sunlight and in hot, humid conditions.
• Energy consumption modeling for building applications in China.

Main Results:

• Achieved a subambient temperature drop of 9.2 °C under direct sunlight.
• Demonstrated a cooling effect of approximately 7.4 °C in hot, moist, and variable extreme environments.
• Showcased tunable cooling performance through adjustable compression ratios.
• Energy modeling indicated a potential 35.4% reduction in cooling energy consumption for buildings in China.

Conclusions:

• The developed CNC aerogel coolers offer a high-performance, tunable passive cooling solution.
• These materials are effective even in challenging hot and humid climates.
• The technology presents a promising pathway for significant energy savings in building cooling applications.