Energy saving effect from squid skin

Inspired by the vibrant skin that changes color in organisms such as squid, researchers at the University of Toronto have developed a water-based system that can reduce energy costs for heating, cooling and lighting buildings.

The platform, which optimizes the wavelength, power and dispersion of light transmitted through windows, offers greater control than existing technologies while keeping costs low due to the use of simple materials, off-stage.

“Buildings use a lot of energy to heat, cool and light the spaces inside them,” says Raphael Kay, who recently earned a master’s degree in mechanical engineering in the Department of Applied Science & Engineering and is an author. the main thing in the new printed paper. in the newspaper PNAS.

“If we can systematically control the amount, type and direction of solar energy entering our buildings, we can greatly reduce the work we ask for heaters, coolers and lighting.”

Now, some “intelligent” technologies such as blinds or electrochromic windows – which change their opacity due to electric current – can be used to control the amount of sunlight that enters the room. But Kay says these systems have a limitation: they cannot distinguish between different wavelengths of light, nor control how that light is distributed in space.

“Sunlight contains visible light, which affects the brightness of a building – but it also contains other invisible wavelengths, such as infrared light, which we can think of as heat,” he says.

“In the middle of the day in the winter, you might want to allow both—but in the middle of the summer sun, you’ll want to allow visible light and not heat. And they do this—they block both or neither. They also do not have the power to direct or spread light in beneficial ways.”

Founded by Kay and a team led by Professor Ben Hatton, the system uses the power of microfluidics to provide an alternative. The team also included Ph.D. candidate Charlie Katrycz, both in the materials science and engineering department, and Alstan Jakubiec, assistant professor in the John H. Daniels Faculty of Architecture, Landscape, and Design.

These models are made of flat sheets of plastic that are filled with a thickness of several millimeters through which fluids can be pumped. Pigments, particles or other molecules can be incorporated into liquids to control how light passes through – such as visible versus near-infrared wavelengths – and how this light is distributed. where.

These papers can be combined in several stacks, and each part is responsible for a different type of optical function: control power, filtering length or correcting the dispersion of light which is transmitted in the house. By using small, digitally controlled pumps to add or remove fluids from each floor, the system can improve light transmission.

“It’s simple and cheap, but it also enables an amazing control of integration. We can create strong water level building facades that do anything you would like to do in track their optical properties,” Kay says.

The work builds on another system that uses embedded pigment, developed by the same team earlier this year. Although that study was inspired by the ability to change colors in marine arthropods, the current system is similar to the squid’s multi-colored skin.

Many types of squid have skin that contains layers of specialized organelles—including chromatophores, which control light absorption, and iridophores, which affect visibility and brightness. These individual resolvable factors work together to produce unique eye behaviors that are only possible through their combined action.

While U of T Engineering researchers focused on prototypes, Jakubiec built​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​a what is strong.

Models were introduced with physical properties measured from prototypes. The team also simulated different control algorithms for turning features on or off based on changing environmental conditions.

“If we had one layer focused on changing the transmission of near-infrared light – so that we don’t affect the visible part of the spectrum – we find that we can save about 25% a year and spring heating, cooling and lighting energy in a static. foundation,” says Kay.

“If we have two phases—infrared and visible—it’s almost like 50%. These are very important savings.”

In the latest study, the control algorithms were created by humans, but Hatton points out that the challenge of improving them will be a suitable task for artificial intelligence – a possible future direction for research.

“The idea of ​​a building that can learn – that can change this dynamic array on its own to improve for seasonal and day-to-day changes in solar conditions – really excites us,” says Hatton.

“We are also working on how to mount this effectively so you can cover the entire building. That will take work but since this can be done with simple, non-toxic, cheap materials, it is a challenge that can be solved.”

Hatton also hopes that the study will encourage other researchers to think creatively about new ways to manage energy in buildings.

He says: “Across the world, the energy that buildings use is very large – even greater than what we use to make products or transport.” “We think that making smart materials for buildings is a challenge that deserves a lot of attention.”