Session: 03-02: Innovative Building Material and Technologies

Paper Number: 169796

169796 - Precipitation-Powered Radiative Cooling Windows: Multi-Junction Triboelectric Nanogrid for Dual-Function Energy Autonomy 

Abstract: 

Buildings face significant energy challenges due to the inefficiency of conventional windows, which account for over 60% of energy loss through heat exchange, leading to increased cooling demands and higher electricity consumption. Additionally, frequent rainfall in many regions represents an untapped renewable energy source, highlighting the need for innovative solutions that address both energy efficiency and sustainable power generation.

Our innovative window design integrates a rain energy harvester with transparent radiative cooling glass, inspired by the wrinkled photonic structures found in Rhyothemis resplendens wing membrane. The radiative cooling component employs a multilayered photonic structure composed of TiO₂, SiO₂, and Ag, engineered to selectively reflect solar radiation while emitting mid-infrared thermal radiation to the cold universe. This design achieves a cooling effect of up to 14°C at glass surface compared to conventional windows and reduces indoor temperatures by 1.8°C below ambient conditions, while maintaining an apparent visible transmittance (AVT) of 34%, exceeding the industry standard of 25%. To seamlessly integrate the radiative cooling and rain energy harvesting functionalities, the system incorporates a transparent, conductive layer that serves as both a structural adhesive and an electrode for collecting electricity generated via triboelectric effects. This rain energy harvesting system generates impressive electrical outputs for impact droplet over 0.5 mA correspond to power density of 92 W m⁻² at a low matching impedance of 60 kΩ. By reducing cooling loads and simultaneously harnessing renewable energy from precipitation, this advanced window technology offers a sustainable pathway toward energy-autonomous buildings that combine passive cooling with renewable power generation.

Presenting Author: Irum Firdous City University of Hong Kong

Presenting Author Biography: Dr. Irum Firdous is a Postdoctoral Fellow at City University of Hong Kong's School of Energy and Environment, specializing in sustainable energy technologies. She completed her PhD in Energy and Environment Engineering at the same institution in 2022, where she now conducts cutting-edge research under the guidance of Professor Edwin Chi Yan Tso. Her work focuses on passive radiative cooling and energy-efficient smart window technologies, leveraging her expertise in nanogenerators and perovskite solar cells. With a notable portfolio of 15 peer-reviewed publications and a U.S.-filed patent, Dr. Firdous is recognized for her contributions to energy science. Her interdisciplinary research bridges materials science with building energy optimization, positioning her at the forefront of sustainable urban development initiatives.