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Prof. Vivien LU integrates green radiative cooling coating with photovoltaics for energy saving in buildings

21 Jan 2025

Research Results

The PolyU Carbon Neutrality Funding Scheme aims to support the application of university research outcomes and to take the campus as a testbed to apply research solutions, with a goal of achieving carbon neutrality on campus and supporting Hong Kong’s goal of reaching carbon neutrality by 2050. With support from the Scheme, Prof. Vivien LU Lin, Member of the Otto Poon Charitable Foundation Research Institute for Smart Energy (RISE), Research Institute for Sustainable Urban Development (RISUD) and Research Centre for Resources Engineering towards Carbon Neutrality (RCRE), and Professor of the Department of Building Environment and Energy Engineering, and her research team, has integrated the solar-driven adaptive radiative cooling (SARC) coating they developed, with bifacial solar photovoltaics (PV) to achieve synergistic enhancement in thermal management and power generation, transforming buildings from energy consumers into energy harvesters. The team is planning to install bifacial PV panels on the rooftops of the under-construction PolyU Kowloon Tong Student Hostel, with new coating applied on the corresponding area under the panels, to enhance power generation while radiatively cooling the buildings.

The carbon dots (CDs)-driven photoluminescent radiative cooling nanocoating can be applied to building rooftops and exterior walls. This novel coating can automatically adjust its absorption and emission of solar and thermal radiation in response to changes in environmental temperature or light conditions, helping to mitigate the heat island effect caused by building materials. It uses photoluminescence technology to convert ultraviolet light into visible light, thereby improving the absorption and utilisation of light by PV and increasing its conversion efficiency.

Compared to traditional coatings, this novel coating can effectively improve effective daytime solar reflectance from 92.5% to 95%, increase the cooling effect by 10% to 20%, and reduce the temperature by up to 25°C when applied to concrete rooftops. This nanocoating is environmentally friendly, water-soluble, volatile organic compounds (VOCs)-free, and can be produced in various colours, thus demonstrating significant application potential.

Press Release: https://www.polyu.edu.hk/media/media-releases/2024/0924_polyu-researchers-unveil-novel-carbon-dots-driven-green-radiative-cooling-coating/

Online coverage:

Sing Tao Headline - https://polyu.me/4hofXLG (Chinese only)


Research Units Otto Poon Charitable Foundation Research Institute for Smart Energy | Research Institute for Sustainable Urban Development | Research Centre for Resources Engineering towards Carbon Neutrality

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