A dual-selective thermal emitter with enhanced subambient radiative cooling performance

Area of Science:

• Materials Science
• Thermodynamics
• Sustainable Energy

Background:

• Radiative cooling leverages Earth's atmospheric transparent windows for passive heat emission to space.
• Current technologies often focus on a single atmospheric window (8-13 μm), limiting cooling potential.
• Another significant window (16-25 μm) remains under-exploited in existing radiative cooling designs.

Purpose of the Study:

• To develop a dual-selective radiative cooling design targeting both atmospheric transparent windows.
• To enhance subambient cooling capacity by utilizing a broader spectral range.
• To demonstrate a practical and scalable solution for sustainable thermal management.

Main Methods:

• Fabrication of a scalable thermal emitter with dual-selective emission properties.
• Characterization of spectral selectivity in both 8-13 μm and 16-25 μm atmospheric windows.
• Evaluation of cooling performance under strong sunlight and assessment of material durability and aesthetics.

Main Results:

• The dual-selective emitter achieved ultrahigh subambient cooling capacity (~9 °C) under direct sunlight.
• The design demonstrated superior cooling performance compared to existing single-window emitters and commercial materials.
• The material exhibited high weather resistance and color compatibility, indicating practical applicability.

Conclusions:

• The dual-selective radiative cooling design effectively utilizes both atmospheric transparent windows for enhanced cooling.
• This approach offers a scalable and practical solution for zero-energy sustainable thermal management.
• The developed technology surpasses current radiative cooling methods in performance and practicality.