Butterfly and Solar: Wings Collect Warmth; Model for Solar

Design inspiration comes in a lot of forms. When it comes to solar panels, engineers sometimes look toward the butterfly. One may not think this little insect is a powerhouse for harnessing solar energy, but a butterfly's beautiful wings offer far more than flight.

Scientists from the Environment and Sustainability Institute (ESI) and the Centre for Ecology and Conservation of the University of Exeter employed biomimicry, or using patterns and techniques from nature in applied science, to help develop a more efficient way to turn light into power, also known as photovoltaic energy.

On cloudy days, a Cabbage White butterfly positions its wings in a v-shape and holds this stance for several moments before taking flight. This posture reflects heat downward, allowing the sun to warm up the insect's "flying muscles" before take off, thus utilizing and converting solar energy into kinetic energy.

Scientists assumed that if this unique positioning works for the butterfly, the same positioning might help solar panels soak up more energy from the sun. This theory proved to be right, as mimicking the Cabbage White butterfly's v-shaped pose increased the solar panel's energy production by 50 percent and making the power-to-weight ratio 17 times more efficient than other structures, according to the study published in Scientific Reports.

This is not the first time scientists have turned to the butterfly as inspiration for solar energy designs. In fact, scientists only recently discovered tht butterfly wings have microscopic, overlapping scales that collect solar energy. In 2009, researchers from Shanghai Jiao Tong University in China used this knowledge to create photoanode structures with butterfly wing scales as templates in order to determine whether the microstructures could harvest more solar energy when distributed in a pattern reminiscent of the scales on a butterfly's wings. And they did. Not only was light absorption increased in the butterfly pattern, surface reflections were reduced, making light harvesting more efficient.

Both of these findings produce more effective solar concentrators because they harvest more light and produce more energy at less weight -- which may help to expand the use of solar energy in businesses and homes in years to come.

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