A Liquid Window That Can Bring Down Energy Consumption of Buildings By Up to 45%

Researchers at the Nanyang Technological University claim that they have developed a liquid window panel that can reduce buildings’ energy consumption by up to 45%.

The researchers said that the liquid window is less expensive and 30% more energy-efficient than commercially available energy-efficient glasses. The liquid window is best suitable for use in office buildings.

According to the report, the researchers placed hydrogel-based liquid, a combination of micro-hydrogel, water, and stabilizer, between glass panels to develop the liquid window.

The researchers explained that a hydrogen-based liquid could respond to a change in temperature as it becomes non-transparent when exposed to heat and blocks the sunlight, while it returns to its clear state when cooled. Besides that, water’s high heat capacity enables the liquid window to store a large amount of thermal energy instead of getting transferred through the glass and into buildings during the day times. The heat will be cooled and released at night, they added.


“By using a hydrogen-based liquid, we simplify the fabrication process to pouring the mixture between two glass panels. This gives the window a unique advantage of high uniformity, which means the window can be created in any shape and size,” said Long Yi, lead author of the research and senior lecturer at the School of Materials Science & Engineering.

As part of the experiment, the researchers conducted outdoor tests in Singapore’s hot environment and the cold climate of Beijing, China.

The researchers stated that the smart liquid window registered a lower temperature (50°C) than a normal glass window (84°C) during the hottest time of the day in Singapore. While the Beijing test revealed that the room equipped with the smart liquid window utilized 11% less energy to keep the same temperature than the room with a normal glass window, the researchers added.

According to the report, the highest value of stored thermal energy peaked at 2 pm for the liquid window compared to 12 pm for the normal glass window.

“If this temperature peak shift is translated to a shift in the time that a building needs to draw on electrical power to cool or warm the building, it should result in lower energy tariff charges for users,” the researchers stated.

The researchers utilized actual building models and weather data from four different cities to demonstrate that the liquid window has a better energy-saving capacity than normal glass windows and low emissivity windows. They also stated that the liquid window could reduce noise pollution by 15% compared to double-glazed windows.

In August 2020, researchers at the University of Michigan said they set a new efficiency record for color-neutral, transparent solar cells. According to lead researcher Stephen Forest, these organic solar cells are compatible with windows that cover the face of most buildings.

Earlier this year, Australian scientists, led by members of the ARC Center of Excellence in Exciton Science, published a research paper stating that they had succeeded in producing semi-transparent perovskite solar cells that generate electricity. This breakthrough could allow for windows in buildings and automobiles to generate electricity.

Image credit: Nanyang Technological University