Shortwave emitters enable radiative cooling of above-ambient vertical surfaces

Area of Science:

• Materials Science
• Thermal Engineering
• Optics

Background:

• Radiative cooling is an energy-efficient heat dissipation method.
• Current materials are limited for vertical surfaces and above-ambient temperatures.
• Effective thermal management is crucial for data centers, power systems, and industrial equipment.

Purpose of the Study:

• To develop a novel thermal radiator for enhanced radiative cooling.
• To improve performance on vertical surfaces and for devices operating above ambient temperature.
• To address limitations of existing radiative cooling materials.

Main Methods:

• Design and fabrication of a thermal radiator with broadband mid-infrared emission.
• Characterization of shortwave emissivity (2.5-8 µm, 91.4%).
• Performance testing under direct sunlight with a 600 W m⁻² heat load on a vertical surface.

Main Results:

• The radiator demonstrated significantly enhanced radiative coupling.
• Achieved temperature reductions of 18.6 °C and 27.0 °C compared to selective emitters and uncoated surfaces, respectively.
• The material showed excellent mechanical robustness, thermal stability, and environmental durability.

Conclusions:

• The developed radiative cooler outperforms conventional selective emitters for vertical ambient cooling.
• This technology holds significant potential for real-world thermal management in vertically oriented, high-temperature systems.
• The material's properties enable efficient heat dissipation in challenging environments.