While double-glazed windows do help save energy, Scientists in Singapore have adapted the concept to make it more effective. Instead of leaving an air gap between the two layers of glass, the researchers added a liquid that absorbs heat and blocks light. The experimental new “smart window”, developed by scientists at Nanyang Technological University in Singapore, consists of two ordinary pieces of glass filled with a solution of patented hydrogels, water and stable compounds.
During the day, when sunlight passes through the window, the liquid absorbs and stores the heat of the light. This keeps the room from heating up and reduces the need to operate air conditioning. In addition, when the liquid heats up, the hydrogel changes from transparent to opaque. Although this destroys the view from the window, it also reduces the visible light passing through the outside, further helping to keep the room cool.
When the sun d’on at night, the gel cools and becomes transparent again, releasing stored heat. Some of the energy enters the room through glass, reducing the need for a building heating system.
As an added bonus, the smart window reportedly absorbs 15% more external noise than traditional double-glazed windows.
Based on simulations and practical tests, scientists have determined that using such windows can reduce energy consumption in office buildings by 45%. The university is now looking for industry partners to help commercialize the technology. Scientists recently published a paper in the journal Joule describing the technique.
Scientists at Loughborough University in the UK have been working on similar systems, but their systems use ordinary water. Once the water is heated by the sun, it is pulled out of the window and stored in a water tank. In the evening, warm water is pumped out of the water tank, into pipes in the walls, and heated inside the building.