Researchers at Nanyang Technological University (NTU) in Singapore developed a smart ‘liquid window’ that can block sunlight to keep a building cool and also absorb heat to gradually release it to cut energy bills.

Windows are the least energy-efficient part of the building. While improvements can be made with double or triple glazing, windows still account for half the heating, ventilation, and air-conditioning energy consumption in buildings.

The liquid window uses a liquid consisting of micro-hydrogel, water, and a stabiliser that is poured between two glass panels. The liquid allows the wind two be more energy-efficient and respond to changes in temperature. When it is sunny out, in 30 minutes, the liquid turns opaque, thus modulating solar transmission. With less sunlight coming in, less energy is needed to cool the building. In addition, the liquid window also works as a sound insulator, 15 per cent more effective than double-glazed windows.

In simulations, it was found that the windows reduced the heating and cooling energy costs by up to 45 per cent. In addition, the new liquid window is 30 per cent more energy efficient than commercially available energy efficient glass, while being cheaper to make.

Images: NTU