High albedo daytime radiative cooling for enhanced bifacial PV performance.

Area of Science:

• Materials Science
• Nanotechnology
• Sustainable Energy

Background:

• Bifacial solar panels can benefit from improved thermal management and light reflection.
• Radiative cooling materials offer a passive method for reducing surface temperatures.

Purpose of the Study:

• To develop and evaluate a novel radiative cooling material for enhancing albedo and reducing ground surface temperatures.
• To assess the material's performance under fielded bifacial solar panels.

Main Methods:

• Electrospinning polyacrylonitrile nanofibers (nanoPAN) onto a polymer-coated silver mirror.
• Characterizing total solar reflectance, albedo, and thermal emittance.
• Outdoor testing to measure radiative cooling power and impact on solar cell photocurrent.

Main Results:

• The nanoPAN material achieved a total solar reflectance of 99%, albedo of 0.96, and thermal emittance of 0.80.
• Demonstrated radiative cooling power exceeding a state-of-the-art control by ~20 W/m².
• Increased photocurrent in a commercial silicon cell by up to 6.4 mA/cm² compared to sand.

Conclusions:

• The developed material exhibits high albedo and high emittance, suitable for radiative cooling applications.
• The material shows significant potential for improving the efficiency and performance of bifacial solar panels.
• Validated essential characteristics for a high-albedo radiative-cooling reflector for thermal and light management.