Let the Sun Shine In: Redirecting
Sunlight to Urban Alleyways
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In
dense, urban centers around the world, many people live and work in dim and
narrow streets surrounded by tall buildings that block sunlight. And as the
global population continues to rise and buildings are jammed closer together,
the darkness will only spread.
To
alleviate the problem, researchers have developed a corrugated, translucent
panel that redirects sunlight onto narrow streets and alleyways. The panel is
mounted on rooftops and hung over the edge at an angle, where it spreads
sunlight onto the street below.
Researchers
expect the device to provide illumination to perform everyday tasks, and
improve the quality of light and health conditions in dark areas. These dimly
lit areas specifically include narrow streets, but the new panel could be used
as a greener, cheaper, and more pleasant alternative to fluorescent and other
artificial light.
While
other commercially available window-like devices can redirect light, they are
designed for shade and redirecting glare or for brightening a room-not a narrow
street. So the researchers decided to create their own design. They wanted a
simple way to redistribute natural light without the need for a tracking device
that follows the rising and setting sun.
What
they came up with is a panel made of polymethyl methacrylate (PMMA), the same
acrylic plastic of which Plexiglas is made. The bottom of the panel is smooth
while the top is covered in ridges that are based on a sine wave, the
mathematical function that describes everything from light to pendulums.
The
researchers used computer simulations to find the size and shape of the grooves
that distribute the most amount of sunlight in a wide range of sun positions
all year round, whether it's high or low in the sky. A sine-wave pattern is
also easy to manufacture.
Using
simulations of sunlight shining on an alleyway, the researchers found that
their panels increased illumination by 200 percent and 400 percent in autumn
and winter, respectively, when sunlight is most limited. They also tested a
small prototype and found that it lit up the area as designed.
The
next step will be to build a full-scale model 10 times bigger to validate their
calculations and to test it in a real alleyway. The team then plans to market
and commercialize the panel.
And
that may be a small price to pay for the benefits of sunlight. The lack of sun
in urban areas doesn't just make life gloomy; it can be harmful to your health.
Research has shown that lack of natural lighting can cause severe physiological
problems, such as serious mood changes, excessive sleeping, loss of energy and
depression.
