New 'impellers' -- modeled on natural spirals -- could help green the shipping industry
As geometric shapes go, the spiral is one of the world's most compelling. It has piqued the curiosity of the world's greatest thinkers, from Plato to Einstein -- and, according to Jay Harman, we've hardly begun to realize the spiral's usefulness. Nature, however, is way ahead of us.
Harman was a young boy swimming off the coast of Australia when he was first struck by nature's use of the spiral shape, writes Kathy Witkowsky in Horizon Air magazine (May 2004). Whenever he grabbed a stalk of kelp, Harman noticed, the seaweed would break easily in his hand. But when it was struck by a turbulent tide, the kelp leaves stayed intact. Harman realized that the leaves survived because rather than fight the current, they moved with it, in a pattern that he would later notice in seashells, weather systems, and even human cells: a spiral.
At 55, Harman is putting what he's learned about the spiral to use through his company, PAX Scientific, an industrial design firm that specializes in fluid movement technology. PAX's flagship design is the 'impeller' -- a new propeller design that just might revolutionize the shipping industry. The classic propellers used by today's freightliners do little to cut down on drag, causing cavitation (air bubbles) that reduces efficiency to around 50 percent. By contrast, Harman's impeller channels water in the spiraling pattern in which it naturally travels. As a result, one six-inch Lily Impeller (named for the flower that inspired its shape) in a municipal water treatment facility can move 1 million gallons of water in just 24 hours, using the same amount of energy as a single household lightbulb.
Early testing shows that the impeller design improves a ship engine's efficiency by up to 10 percent. While that might not sound too impressive, the actual implications are tremendous. According to the Encyclopedia of Energy, marine cargo ships burn 200 metric tons of diesel fuel every year. One freighter can go through 10,000 gallons in a single day. The industry as a whole spends $43 billion a year on fuel, and as a result, it considers a 1 percent increase in propulsion efficiency money in the bank. A 10 percent increase (meaning savings of more than $4 billion industrywide) is unheard of.
And the benefits extend further than the bottom line. Exhaust emissions from waterborne vessels are a primary source of the sulfur dioxides and nitrogen oxides that cause acid rain. Every year, ships belch five tons of each into the atmosphere. And global shipping traffic is expected to double by 2020. By reducing the industry's dependence on fuel, Harman's impeller could make the whole industry vastly greener.
If Harman has his way, his invention will transform not just ship propellers, but also fans, turbines, fuselages, air and water purifiers, industrial mixers -- any technology that requires the movement of fluid. According to Harman, that's 'most fields of human endeavor -- from architecture to engineering, from medical science to aerospace.' Implemented that way, this little seaweed-aping gadget really could change the world.
Harman's impeller is an example of biomimicry -- the idea that humans can learn a lot from nature's 4.5 billion years of design experience. Writer and naturalist Janine Benyus coined the term in her 1997 book Biomimicry: Innovation Inspired by Nature (William Morrow), but the idea is hardly new. People have been fashioning boat hulls after the shapes of fish for thousands of years. Solar panels were inspired by plant leaves, Velcro by cockleburs. With so many successful examples, you'd think modeling technology after nature would be the norm. But as Harman told an audience at the annual Bioneers conference in San Rafael, California, last October, it's more affordable for manufacturers to stamp out straight lines than curves. 'But,' he noted, 'nature never travels in straight lines.'
Today the technology exists to affordably mass-produce curved lines. That fact, combined with the increasing desire to reduce energy waste, is creating a sudden demand for Harman's ideas. Like the boats driven by his impellers, spirals are charging full steam ahead.
TELL ME MORE
You can hear an interview with Jay Harman on PRI's Studio 360 with Kurt Andersen, public radio's weekly program on creativity, pop culture and the arts, by going to www.wnyc.org/studio360
The Bioneers Conference is an annual gathering of those who seek 'visionary & practical solutions for restoring the earth and people' in San Rafael, California. To read about the work of other Bioneers, go to >