Krill-inspired solar shades could reduce energy bills by up to 30 percent
Researchers at the University of Toronto have learned a thing or two about adapting to their surroundings from krill, the tiny crustaceans found in the oceans. They now want to use this knowledge to build a greener, more adaptive buildings in the future, a university press release said.
The modern building is a static structure. It warms up with the sun's rays and cools down when it snows. To keep the temperatures inside habitable, we either need to use air-conditioning or heating in different parts of the world.
With changing climate conditions, we are now entering a stage where buildings need to be warmed up and cooled down during different parts of the year simply because the structure cannot regulate its own temperature.
In contrast, living beings constantly regulate their body temperature. Researchers at the University of Toronto were working on how such capabilities could be added to buildings when they cross the Atlantic krill.
Learnings from the krill
Krill are transparent organisms which means that the ultraviolet light from the sun can enter through their skin and damage their internal organs. Krill deploy a simple and effective shading system to protect themselves from the sun. During their time in the sun, the krill use a colorful pigment under their skin and darken themselves. When under dark conditions, they remove the pigment to become lighter in color again.
A similar method could be on buildings' facades and window panes to let light in or block it. Using window blinds could be described as a similar application of the concept. However, the researchers think for such a system to be highly efficient yet personalized to the needs of different building users, and it would have to be automated and optimized for various users, which would end up increasing the costs of deploying such a technology.
Using low-cost optofluidics
The researchers turned to the low-cost option of optofluidics to achieve better results. Their prototype optofluidic cells consisted of two sheets of transparent plastic and a layer of mineral oil sandwiched between them. A tube connected at the center of the cell was used to inject a small amount of water.
Like in the krill, the water contains a pigment or a dye that can darken the cell. The pump works two ways and can be used to remove the pigmented water when required.
To determine the efficiency of their method, the researcher built computer models and simulated how a fully automated and optimized system would work when compared to motorized blinds or windows that can be programmed to change color using electronics.
"We found that our system could reduce the energy required for heating, cooling, and lighting by up to 30 percent," said Raphael Kay, a master's student at the University, who works on the project. "The main reason for this is that we have much finer control over the extent and timing of solar shading. Our system is analogous to opening and closing hundreds of tiny blinds at different locations and times across a facade. We can achieve all this with simple, scalable, and inexpensive fluid flow."
Interestingly, the researchers also found that they could create pointillist-style artwork using this technique. During their research, they also created simulated images of Albert Einstein using this technique which could one day even adorn our buildings.
The research findings were published in the journal Nature Communications.
Typical buildings are static structures, unable to adjust to dynamic temperature and daylight fluctuations. Adaptive facades that are responsive to these unsteady solar conditions can substantially reduce operational energy inefficiencies, indoor heating, cooling, and lighting costs, as well as greenhouse-gas emissions. Inspired by marine organisms that disperse pigments within their skin, we propose an adaptive building interface that uses reversible fluid injections to tune optical transmission. Pigmented fluids with tunable morphologies are reversibly injected and withdrawn from confined layers, achieving locally-adjustable shading and interior solar exposure. Multicell arrays tiled across large areas enable differential and dynamic building responses, demonstrated using both experimental and simulated approaches. Fluidic reconfigurations can find optimal states over time to reduce heating, cooling, and lighting energy in our models by over 30% compared to current available electrochromic technologies.
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