The invention of a “liquid” window to save up to 25% on heating and air conditioning

Building energy-efficient buildings is becoming a global challenge in the fight against global warming. We know that most old buildings are energy-intensive, but it’s impossible to rebuild them all. Researchers at the University of Toronto (Canada) have just developed a “Liquid windows” technology or multilayer liquid window which could provide a solution to energy saving in buildings. According to the inventors of this new concept, these innovative windows could be installed on existing buildings. They are said to be inexpensive and relatively easy to manufacture. Presentation.

Liquid windows, what are they?

“Smart” windows already exist, such as some that can be electronically switched to block sunlight or let it in. The new multi-layered window invented by the Canadian researchers could be set to different light filtering modes. Consequently, they would make it possible to achieve energy savings. On existing photochromic windows, it is possible to adjust the amount of light that passes through the window. The glass then partially blocks the visible spectrum to decrease the brightness, also blocking the infrared spectrum to limit the heat in the room. For the researchers, users might need light without heat in summer for example, but not in winter. However, the current windows do not allow this selection.

A window capable of adjusting the amount of light that passes through the glass. Photo credit: Video screenshot

What are the “Liquid windows” inspired by?

“Liquid windows” were developed by a team of scientists from the University of Toronto, led by Professor Ben Hatton. Like many current inventions, they are manufactured according to the principle of biomimicry. Remember that biomimicry is the act of transposing the essential properties of a plant or animal biological system to meet human needs. For the “Liquid windows”, it was squid, cuttlefish and krill that inspired the researchers. These marine animals have the ability to move pigments into the cells located under their skin, changing them from a transparent state to an opaque state. Transposed to a window, this faculty of calamari translates into a prototype that consists of several stacked sheets of transparent plastic. Each sheet being traversed by micro-channels a few millimeters thick.

How it works ?

By pumping liquids containing different pigments (or other molecules) in and out of the channels of each sheet, different combinations of optical qualities can be selected for the entire window. For example, by pumping pigments that block visible light in foil and pigments that block infrared light in another, the window can be adjusted to let in visible light while blocking infrared light. Also, pumping light diffusing paint in or out of the other sheet helps adjust the softness/intensity of the sunlight visible in the room.

The inventors explain that it is also possible to inject a colored aqueous solution into the glass.
The inventors explain that it is also possible to inject a colored aqueous solution into the glass. Photo credit: Video screenshot

The scientists behind this study believe that “Liquid windows” could helpsave about 25% on heating and air conditioning every year. If these windows were also used for visible light control, then the annual savings would be 50%. ” Buildings use a ton of energy to heat, cool and light the spaces they contain” explain Raphael Kay, lead author of an article on the study. If it becomes possible to control the type and direction of solar energy, in addition to the desired amount, then the reduction in consumption could be substantial! Find the full study in the journal PNAS.

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