UV-Cured Robust and Transparent Double-Layer Membrane on Windows for Water Harvesting and Room Cooling

Area of Science:

• Materials Science
• Sustainable Architecture
• Energy Efficiency

Background:

• Global warming drives increased demand for cooling energy, straining conventional air conditioning systems and contributing to carbon emissions.
• Modern glass facades, while architecturally significant, trap solar radiation, leading to heat buildup and exacerbating the greenhouse effect.
• Existing cooling solutions often lack transparency or energy efficiency, posing challenges for sustainable building design.

Purpose of the Study:

• To develop an energy-saving, transparent cooling solution for glass buildings.
• To mitigate the heat-trapping effect of glass facades.
• To introduce a sustainable approach to building climate control with potential for water recycling.

Main Methods:

• Utilized roll-to-flat and light-curing technology to apply a hydrogel coating onto a glass substrate using ultraviolet (UV) adhesive.
• Engineered the hydrogel to selectively absorb ultraviolet (UV) and infrared (IR) light while permitting visible light transmission.
• Implemented a dual-mode cooling strategy: active cooling via UV/IR absorption and passive cooling through water's phase change enthalpy.

Main Results:

• The hydrogel coating significantly reduced room temperatures by up to 8.1 °C under 0.75 sun irradiation.
• Achieved a total room cooling power of approximately 192.6 W m^-2, demonstrating substantial cooling efficacy.
• Maintained glass transparency, ensuring aesthetic and functional integrity of building facades.

Conclusions:

• The developed hydrogel coating offers a novel, transparent, and energy-saving solution for cooling glass buildings.
• This technology effectively addresses the challenges of solar heat gain in buildings, contributing to reduced energy consumption.
• The approach presents opportunities for water resource recycling, further enhancing its sustainability profile.