A revolutionary glass coating promises major energy savings by reducing heat loss during colder months. This innovative material forms a tough, transparent layer that outperforms existing low-emissivity coatings and has a broad range of potential applications.
Researchers from Rice University, the Chinese University of Hong Kong and their collaborators have developed an innovative glass coating that could significantly reduce energy bills by preventing heat loss during colder months.
The breakthrough, published in Advanced Materials, involves a transparent film made by weaving carbon into the atomic structure of boron nitride. This film forms a durable layer that reflects heat, resists scratches and remains unaffected by moisture, UV light and temperature changes.
In simulations, the new material improved energy savings by 2.9% compared to existing alternatives in cold-weather cities like New York, Beijing and Calgary.
With over 4 billion square feet of new windows installed annually in the United States, these savings could become substantial.
“Although pure boron nitride shows almost similar emissivity to glass, when you add a little amount of carbon into it, the emissivity lowers significantly ⎯ and this changes the game altogether,” corresponding author Pulickel Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor of Engineering and professor of materials science and nanoengineering, said in a news release.
Traditional low-emissivity (low-E) coatings must be placed on the interior side of windows because they degrade from humidity and temperature changes.
However, the new coating’s durability allows it to be applied on the exterior-facing side, providing a significant advantage.
To create the coating, the team used pulsed laser deposition, a technique using high-energy laser bursts to apply the coating at room temperature, avoiding the need for high heat.
“From the synthesis point of view, coating boron nitride on glass is truly amazing and very exciting,” added lead author Abhijit Biswas, a research scientist at Rice University.
Ajayan also highlighted the broad applicability of the low-temperature deposition technique to other materials such as polymers and textiles. This coating could potentially be produced commercially using scalable methods like roll-to-roll chemical vapor deposition, with optimization efforts underway.
“This broadens the application space for boron nitride coatings significantly,” Ajayan added, noting that boron nitride is less expensive than materials currently used in commercial low-E glass.
Testing in outdoor conditions revealed the coating’s high weatherability, a clear distinction from existing technologies.
“The high weatherability makes it the first outdoor-facing low-E window coating, with an energy-saving capacity that clearly outperforms the indoor-facing counterpart,” added co-corresponding author Yi Long from the Chinese University of Hong Kong. “It could be an excellent solution in densely built environments.”
As urban areas look for ways to reduce energy consumption, this new coating could offer an effective solution.
“The transparency level and promising low emissivity makes carbon-doped coated glass a competitive energy-saving option for cities like Beijing and New York,” added co-author Shancheng Wang from the Chinese University of Hong Kong, another significant contributor to the project.
The research also included contributions from Arizona State University, Cornell University and the University of Toronto.
Source: Rice University