When Raphael Kay and his colleagues at the University of Toronto were considering ways to redesign windows to make them more energy efficient, they looked no further than the natural world. Specifically, they took inspiration from a tiny sea creature. Krill, perhaps best known as whale food, has an ingenious way of protecting itself and its organs from harsh sunlight. Kay explains, “they basically have a bunch of dots, of pigments, and they store them within cells along their skin.” When it is dark out, these dots of pigment are tucked away in the centre of the cell. But when the sun is bright, a signal is sent that rallies these dark pigments which spread across the surface of the krill and protect it from the ultraviolet light and radiation.
So, what does any of this have to do with windows? “When we think about shading buildings,” Kay explains, “we use bulky solid components.” Shutters, blinds, exterior shades. But the concept of biomimicry examines how nature performs its tasks, such as protecting the krill from sunlight. Kay and his colleagues considered that what they were trying to achieve—reduce how much sunlight got through windows, thereby reducing the heat in a building and boosting energy-efficiency—and mimicked how krill respond. The result? A window that uses a thin layer of liquid pigment between two glass panes to affect how much sunlight gets through.
Kay and his team are currently playing with prototypes, testing out different patterns and viscosities of pigment, as well as various ways to trigger the pigment. They’re also considering their prototypes’ thermal and optical properties, as well as using sophisticated energy modelling to determine how these windows might warm (or not) in a real building. The team is excited about the results, noting that early predictions show that these windows can achieve an energy savings of between 30 and 43 per cent.
While you won’t find these windows at your neighbourhood building store in the very near future, don’t be surprised if your future cottage is equipped with these energy-saving options. And such a future is only possible because a tiny sea creature long, long ago figured out how to protect itself from the sun—and some astute determined researchers took notice.