Engineers are designing more efficient cooling systems inspired by physical processes in nature.
Nature-inspired engineering. I’m Bob Hirshon and this is Science Update.
[furnace fan] In our heating and cooling systems, [ventilation fan] ventilation, [computer fan] even in our computers, fans are everywhere. Inventor Jay Harman, CEO of PAX Scientific, says they account for over twenty percent of the world’s power use—a number that could be reduced significantly, if engineers paid more attention to the way Mother Nature moves fluids: in a vortex, or whirlpool.
When we reverse-engineered a whirlpool, and built a fan according to it, we can reduce the energy of fans by up to forty-seven percent.
He recently completed a project to cut the energy needed to cool banks of computer servers and has similar designs for other home and industrial uses. In fact, he claims many of the world’s energy problems could be reduced by turning to Mother Nature as chief engineer. I’m Bob Hirshon, for AAAS, the science society.
Making Sense of the Research
You may have never thought about how ubiquitous fans are in our daily lives. You are probably familiar with ceiling fans and standing fans. And, you've probably heard the fans that are in your heating and ventilation system at home. Did you know, though, that fans also are found in things like computers, exercise equipment like ellipticals, machines used in textile factories, welding machines, and more? The fans in these machines serve the same purpose as those we use to cool our homes: they are meant to help keep the machines from overheating.
Since fans are used in so many things and are responsible for approximately 20 percent of global electrical energy use, it is important to make sure that they are efficient and don't use too much energy. Traditionally, it has been generally assumed that the technology required to move gases and liquids—propellers and pumps—should be based on the idea that the path of least resistance is always a straight line. Liquids and gases, however, move in a swirling path. Attempts to move liquids and gases along a straight path create back-pressure, increase friction, reverse heat gain, and create cavitation (formation of cavities, or bubbles, in a liquid).
Jay Harman has been working on trying to make more energy-efficient fans by studying how these liquids and gases move or flow. Harman and his colleagues studied the geometries of the flow of liquids and found that it moves in a consistent pattern, a three-dimensional centripetal spiral. This shape is common throughout everything, from the spiraling galaxies to a whirlpool. It took Harman 20 years to freeze a whirlpool so that he could see all the movement of the liquids. What he discovered was that it could be described with one algorithm with four variables.
Harman and his team think that they should employ the flow of liquid to help develop the shapes of fans. That is, they want the fans to work with of flow of fluids rather than against it. In order to do this, they are turning to biomimicry, the process of looking to nature for solutions to problems facing humans. According to Harman, "Even though it was first coined by Janine Benyus about 15 years ago, it's hit the vernacular in the last year or two. People all over the world are waking up to this."
By reverse-engineering a whirlpool, Harman and his colleagues have developed fans that are 25 percent more efficient than conventional ones. But, Harman doesn't want to stop there. He and other scientists believe that this approach can be used to design more efficient versions of other machines and thereby help reduce the amount of energy needed to use them.
Now try and answer these questions:
- In what kinds of equipment are fans found?
- What percent of global electrical energy do fans use?
- What is biomimicry?
- What did Jay Harman study to help him develop a fan that would be more efficient?
- Can you think of other things in nature that could be studied to help design new machines or systems or to improve on the designs of existing ones?
You can learn more about how scientists study the natural world for inspiration with this Science Update Podcast from January 7, 2011, on the Nature of Invention. Topics covered in this podcast include how sea urchin teeth could inspire new nano-materials, hornet stripes could lead to better solar technology, and automatic transmissions could revolutionize electric wheelchairs, in addition to new research on the genetics of hair color and male pattern baldness.
In the Science Update, Sea Sponge Fibers, you can learn how scientists are finding the secrets to improving fiber optics from the ocean depths.
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You could extend the ideas in this Science Update by having students listen to Gecko Feet, which explains how scientists are trying to create artificial microfibers that act like gecko feet.
This Science Update would make an excellent addition to a high-school engineering class. You could use it to show students how scientists look to and study the natural world to help them solve technological challenges and devise new products. This Science Update also could be used to enhance any lessons or units you do on the nature of science.
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