Spectrally engineered textile for radiative cooling against urban heat islands

TLDR

Radiative cooling textiles promise personal thermal comfort, but urban heat islands absorb emitted radiation, reducing their effectiveness. We developed a mid‑infrared spectrally selective hierarchical fabric (SSHF) with dominant emissivity in the atmospheric transmission window, minimizing net heat gain from surroundings. The SSHF reflects 97 % of solar radiation via Mie scattering and is 2.3 °C cooler than a broadband emitter in simulated urban outdoor conditions while maintaining wearable properties.

Abstract

Radiative cooling textiles hold promise for achieving personal thermal comfort under increasing global temperature. However, urban areas have heat island effects that largely diminish the effectiveness of cooling textiles as wearable fabrics because they absorb emitted radiation from the ground and nearby buildings. We developed a mid-infrared spectrally selective hierarchical fabric (SSHF) with emissivity greatly dominant in the atmospheric transmission window through molecular design, minimizing the net heat gain from the surroundings. The SSHF features a high solar spectrum reflectivity of 0.97 owing to strong Mie scattering from the nano-micro hybrid fibrous structure. The SSHF is 2.3°C cooler than a solar-reflecting broadband emitter when placed vertically in simulated outdoor urban scenarios during the day and also has excellent wearable properties.