Reducing energy consumption related to heating, ventilation and air conditioning is a fundamental priority today. Air conditioners and heat pumps are known to be energy intensive, and limiting their demand is a decisive step towards decarbonizing the residential sector. Thanks to recent research into passive cooling, a significant discovery has been made that promises to transform the energy efficiency of buildings.
A team of scientists from Pohang University of Technology (POSTECH) and Korea University in South Korea presented a new study published in Advanced Functional Materials. Their innovation could represent a turning point in the design of windows capable of reducing energy consumption and improving the sustainability of buildings.
The importance of windows in the climate regulation of internal environments
Windows are not just architectural elements, but essential parts for the internal comfort of buildings. Their design and location directly influence air circulation and the entry of natural light into the rooms. However, they also constitute a major source of heat loss: during the winter, around 25% of internal heat is lost through them, while in the warm months, up to 75% of penetrating sunlight can significantly increase internal temperatures.
To solve these problems, Professor Junsuk Rhoauthor of the study, and his team have developed an innovative coating designed for window glass. This solution aims to optimize the control of heat and light, while improving the energy efficiency of buildings.
How the new glass coating works: three layers for optimal efficiency
The coating is made up of three distinct layers:
- Polydimethylsiloxane (PDMS) top layer: This material emits far infrared radiation, perceived as heat, and helps keep the temperature balanced.
- Intermediate layer of silver: thin and transparent to visible light, it reflects much of the remaining solar spectrum, reducing internal heating.
- Bottom layer, a Bragg mirror: made up of alternating layers of titanium dioxide and magnesium fluoride, it reflects wavelengths of the near-infrared spectrum.
This multi-layer configuration allows the glass to effectively control the entry of heat and light, optimizing internal comfort and reducing the load on air conditioning systems.
Revolutionary, commercial-ready passive cooling
During tests, the new coating demonstrated a significant impact: the surface of the treated glass was well 22.1°C colder compared to a glass coated only with PDMS. This result represents a first in passive cooling technology.
According to Professor Rho, this technology is already ready for mass production and could be applied on a large scale in architecture and environmental contexts. This is a concrete step towards creating more sustainable buildings that are less dependent on traditional energy systems.
