Could this glass alternative regulate building heat?

A window film provides glare protection and radiative cooling, as well as self-cleaning properties

Spotted: Maximising natural light in buildings is one way of saving on energy costs. However, using glass for roofs and walls also comes with problems, including glare and lack of privacy, as well as overheating in warm weather. Researchers at the Karlsruhe Institute of Technology (KIT) have now developed a possible solution.

Researchers at KIT’s Institute for Microstructure Technology (IMT) and Light Technology Institute (LTI) have created a polymer-based film that could replace glass. The film is made up of microscopic silicone pyramids – each one about one-tenth the diameter of a hair. The design allows the film to provide light diffusion and radiative cooling while also maintaining a high level of transparency. Plus, the material is also hydrophobic and self-cleaning.

Bryce S. Richards, Professor at IMT and LTI, explains that a key feature of the film is its ability to efficiently radiate heat through the atmosphere’s “long-wave infrared transmission window”. This means that heat is not absorbed into the atmosphere, allowing for passive radiative cooling without electricity consumption.

Researchers tested the material in the lab and in real-world conditions and found that it achieved six degrees Celsius of cooling, compared to the ambient temperature. The micro-pyramids also gave the material a blurry appearance, making it perfect for use in areas where privacy and low glare are required.

Written By: Lisa Magloff