Windows in buildings are vital components in its design, but they are also the least energy-efficient part because heat can easily transfer through the glass, which significantly impacts heating and cooling costs.
Buildings account for 40% of global energy use, and windows play a big part in that energy consumption, based on the 2009 report by the United Nations. That is why various energy-efficient windows were invented in the past years to address that problem. Scientists all over the world continue to innovate to address these problems.
Recently, Singaporean scientists at Nanyang Technological University (NTU) announced that they had developed a liquid-filled window inspired by double-glazed windows that also saves energy. They tweaked a little bit of the technology to make it a little more effective.
The liquid-filled widow can block solar heat and traps it that can be released at night, therefore regulating solar transmission. This new technology can help save energy since using an air conditioner or heater will be lessened.
Liquid-Filled Window Regulates Solar Transmission
The new 'smart window' from NTU consists of two panes of glass filled with hydrogel-based liquid, water, and stabilizing compound in between. This can reduce up to 45% of energy consumption in buildings compared to those who have ordinary windows. Also, it is cheaper and 30% more efficient than the low-emissivity windows available in the market.
Furthermore, it is the first energy-saving window that uses liquid components and supports the vision of NTU Smart Campus to develop technologically advanced solutions for a sustainable future, according to Science Daily.
The window works both during daytime and nighttime. The liquid inside it absorbs solar heat during the day and stores the thermal energy to keep the room temperature from rising and reduce the use of air conditioning appliances. As the liquid warms up, it becomes opaque that blocks the light from the outside to help further cool the room.
When nighttime comes, the liquid cools down, and the window becomes clear again. It releases the stored thermal energy wherein some of it passes through the glass and into the room, which reduces the demand for the building's heating system.
Increases Sound Insulation Between Glass Panels
Not only does the liquid-filled window regulate solar transmission, but soundproof tests have also shown that it can reduce noise by up to 15% more effectively than the double-glazed windows.
According to Wang Shancheng, the study's first author and Project Officer at the School of Materials Science & Engineering, the double-glazed window and the smart window are similar in the sense that both consist of two glass panels.
The only difference between the two is that the former is filled with air, while the latter is filled with hydrogel-based liquid that increases its efficiency in soundproofing between the glasses. Therefore, the smart liquid window offers an additional benefit not found in energy-saving windows.
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