Passive and Dynamic Phase-Change-Based Radiative Cooling in Outdoor Weather

Area of Science:

• Materials Science
• Thermodynamics
• Optics

Background:

• Radiative cooling offers significant potential for passive cooling by leveraging deep space as a cold reservoir.
• Conventional static radiative coolers suffer from overcooling due to continuous operation in both hot and cold conditions.
• Dynamic radiative cooling using phase-change materials is highly desirable but lacks experimental outdoor demonstration.

Purpose of the Study:

• To experimentally demonstrate practical outdoor phase-change-based dynamic radiative cooling.
• To develop a self-adaptive radiative cooling system that operates efficiently under varying weather conditions.
• To overcome the limitations of static radiative coolers through dynamic thermal management.

Main Methods:

• Engineered vanadium dioxide (VO2) phase-change material for room-temperature phase transition.
• Designed a reconfigurable cavity with a lossless spacer for enhanced thermal modulation and suppressed solar absorption.
• Implemented a selective-filtering method to block solar irradiance while allowing thermal emission.

Main Results:

• Demonstrated dynamic radiative cooling in actual outdoor weather conditions.
• Achieved a self-adaptive switch between ON-cooling (hot daytime) and OFF-cooling (cold nighttime) states.
• Validated the combined performance of engineered materials and photonic structures for intelligent thermal control.

Conclusions:

• The developed dynamic radiative cooler successfully operates in real-world conditions, adapting to ambient temperatures.
• This work provides a viable solution for intelligent thermal management and advances the multifunctionality of radiative cooling devices.
• Offers guidance for future phase-change-based radiative cooling system designs.