Spectrum-Selective Cooling Fabric for Urban Apparel
Summary
Improved personal thermal comfort in hot urban environments, with potential to reduce air-conditioning demand and heat-related health risks, is offered by a breathable textile that selectively radiates heat through the atmospheric transmission window while reflecting solar and surrounding infrared radiation.
The Unmet Need
Conventional clothing can absorb solar and urban heat, undermining outdoor thermal comfort
Conventional fabrics can absorb substantial solar radiation and provide limited cooling. Many radiative-cooling textiles are designed as broadband mid-infrared emitters and evaluated horizontally with an unobstructed view of the sky. In real urban use, clothing is predominantly vertical and faces heat-radiating pavement and buildings, which can compromise cooling performance.
Growing interest in passive cooling reflects efforts to maintain thermal comfort and protect health in a warming climate while reducing reliance on air conditioning. Advances in engineered textiles and spectrum-selective materials create an opportunity to adapt radiative cooling to the orientation and thermal conditions encountered in cities.
The Proposed Solution
A layered, spectrum-selective textile reflects sunlight and directs thermal emission through the atmospheric window
The textile combines an electrospun polymethylpentene (PMP) outer layer with a silver-nanowire infrared-reflective layer and a wool inner layer. Its nano–micro fiber structure scatters sunlight, while selective emission through the 8–13 μm atmospheric transmission window allows heat to radiate toward space and infrared reflection helps limit heat gain from nearby urban surfaces. Unlike broadband radiative-cooling fabrics designed around horizontal, open-sky conditions, this design is optimized for vertically oriented clothing. Reported measurements include approximately 95.9% solar reflectivity and 68.3% average atmospheric-window emissivity; outdoor testing showed cooling of about 6.2°C under peak sunlight, and vertically oriented fabric was about 3.1°C cooler than commercial cotton in a simulated urban setting. The textile is reported to be breathable, washable, mechanically robust, and resistant to UV aging, with optical properties retained after 25 washing cycles.
Key Advantages
- Enhanced cooling in urban environments
- Reduced solar radiation absorption
- Selective heat emission toward space
- Performance optimized for vertical wear
- Breathable and water-repellent construction
- Durability through washing and UV exposure
Applications
- Outdoor apparel for hot urban climates
- Sportswear for outdoor activity in heat
- Hot-climate clothing for heat-risk reduction