Friday July 6th 2012

Bio Mimicry: How Solar Technologies are Copying Nature

You might think that solar energy is a relatively recent human invention; however, some form of solar energy has existed on earth for as long as microbes, plants and animals have existed. Without our sun, life as we know it on earth could not exist; life is completely dependent on solar energy. Current technological innovations that allow the use of the sun as a source of energy are actually little more than a copy of processes found already in nature.

The human race has always looked to nature to help improve its lot in the world, from the first man who found a sharp stone and used it as a knife; to the flint knappers who carved arrowheads from rock. Nature and the technological development of the human race have gone hand in hand for as long as the two have existed.

Humans are now beginning to attempt to transfer their power consumption to a more sustainable technology, and one of the most promising such options is solar power. Although solar power in some form has existed for some time, scientists are now attempting to learn from nature to improve current solar power collection and storage designs.

The “Golden Triangle”

Phyllotaxy refers to the arrangement of leaves on the stem of a plant. Scientists now realize that these arrangements were designed to maximize leaf exposure to the sun. For example, the florets (petals) of a sunflower are arranged in what is known as a Fermat spiral pattern. Within the Fermat spiral the sunflower also uses what is known in geometry as the “Golden Angle” of 137.5 degrees to space each petal. The golden angle allows maximum efficiency for the sunflower petals to gather sunlight. MIT researchers applied the combination of Fermat’s spiral and the golden angle to solar panel heliostats, which are the mirrors used to direct sunlight to man-made solar panels throughout the day. The altered arrangement led to a 10 percent increase in efficiency for the area studied.

The Wings of a Butterfly

Meanwhile, another improvement in the rate of solar collection and energy storage is being developed through the study of butterfly wings. The wings of butterflies are much more complex than originally thought. Scientists now know that butterfly wings, although they are extremely thin and light, are made up of a complex structure of overlapping rectangular scales. Throughout this structure are gaps leading to a lower layer of scales. The steep walls on the ridges of the upper scale absorb long wavelengths of light, while filtering the light to allow only the shorter wavelengths to reach the lower scales. This maximizes the use of all the light that reaches the wing. By treating a butterfly wing with a compound catalyst, it was found that hydrogen could be produced at double previous rates. As hydrogen can be stored and used in fuel cells, this could provide an answer to storing enough power for use at night and during other low light situations.

If the history of technological development has proven anything, it is that the design of natural systems often surpasses anything scientists can create. It will be intriguing to see what new developments in solar power remain to be discovered from the study of our planet.

Guest post contributed by Kris Rayner, on behalf of www.GeneralWasteCollection.co.uk



This article was originally posted on Natural Environment.