Revolutionary Window Coating Could Turn Skyscrapers into Power Plants
NANJING, CHINA – A new technology developed by scientists at Nanjing University could dramatically change how buildings harness solar energy. Researchers have created a colorless coating,utilizing cholesteric liquid crystals (CLCs),that can be applied to windows to capture and concentrate sunlight,perhaps powering household devices and contributing to the renewable energy market.
CLCs, typically used in thermometers and color displays, possess a unique helical structure that allows them to reflect light. The team engineered a colorless and unidirectional solar concentrator (CUSC) by layering multiple CLCs onto glass. This CUSC redirects sunlight to the edge of the glass, were it’s captured by integrated silicon-photovoltaic cells.
The application process involves a meticulous cleaning procedure utilizing high-frequency sound waves to ensure a pristine surface. In initial tests, a prototype CUSC applied to a 1-inch (2.5 centimeter) diameter glass sample successfully powered a 10mW fan outdoors in Nanjing during the summer months.
Researchers believe the technology will be most effective in cities located near the equator, due to consistently higher levels of sunshine. The study acknowledges the potential impact on natural room heating from sunlight, but doesn’t currently address this effect.
The development arrives as architectural trends shift.While the proliferation of super high-rise buildings was previously a focus, China banned new buildings exceeding 1,640 feet (500 meters) in 2021, and now restricts structures over 820 feet (250 meters), with even tighter regulations in smaller cities.
Estimates suggest a typical 6.5 feet (2 m) wide window coated with the CUSC could increase solar energy capture by 50 times.However, further research is needed to determine performance with standard residential and commercial window sizes. Crucially, questions remain regarding the coating’s durability and resistance to environmental factors like rain, hail, snow, and bird droppings, as the study does not currently detail any protective layer. Adding such a layer could potentially impact energy capture efficiency.
Despite these challenges,the CUSC represents a significant advancement in building-integrated solar technology and holds promise as a key component of the global transition to renewable energy sources.
