Alternative Energy Fusion, by R. Eady, QEF, G. Busch, ErgoDynamik, GmbH
Camping out at Earthdance this year? Forget pocketfuls of batteries. Forget needing to take an external plug in. And especially forget those nifty Faraday-effect survival flashlights—you know, the ones you shake back and forth until you have carpal tunnel syndrome and it starts to look vaguely obscene. The ultimate human-powered camping gadget is here: backpack generator. (That is, when you don’t have a Soldius Compact Solar charger -- courtesy of Earthdance, www.soldius.com or through the donation page of www.earthdance.org)
For years, researchers have tried to extract electricity out of motions that people make anyway. That’s a tall order, as most of the energy of walking or dancing is expended within the body itself. Barring surgery, the only ways to get at it have been through shoes or exoskeletons. Using an exoskeleton to capture energy from gross limb motion is cumbersome, to say the least—especially as extra effort is required to generate the electricity. So most researchers have turned to shoes.
Piezoelectric shoes and their more evolved kin haven’t performed too well. When the foot strikes the ground, it exerts force, but the foot stays planted. Since work = force X distance, essentially no work is performed between heel and ground. The shoes get around that by having a lot of give, but that makes dancing or walking rather unpleasant.
Enter Lawrence C. Rome, Taeseung Yoo, and others at the University of Pennsylvania. They reasoned that a backpack actually joggles up and down a lot, so why not try to suck energy out of that? Inspired by self-winding watches, they put together a backpack with the weight on springs. When a person walks, the weight bobs up and down, driving a generator. They stuck the rather heavy (20-38 kg, 44-84 lbs) backpacks on some volunteers, and folks started walking.
The result was magical
Prototype backpack devices generated a peak wattage three hundred times that of the best trick shoes (about 7.4 watts compared to 10 or 20 milliwatts). Seven watts isn’t bad—it’s enough to run three cell phones, two GPS devices, and your iPod. What’s more, when loaded with the springy backpacks, walkers were more efficient than those carrying equally heavy traditional backpacks. The researchers predicted the backpacks would cost an extra 48 watts of metabolic power, but the walkers only expended 19, resulting in power savings around 60%. Talk about your power walkers.
Twin Principles in Action: NIA and IHPM
The cause for the improved walking is just being teased out by the Quest Educational Foundation and the German Sports University in Cologne. Lead investigator and QEF Founder, Randy Eady and Professor Frank Sommers are uncovering some very interesting patterns regarding the body’s ability to harness neuro-muscular integration via the parasympathetic (voluntary, but unconscious ) nerve pathways used for helping the body maintain equilibrium (the researchers call this Neuromuscular Integrative Action, NIA). Initial findings show that it’s clear the volunteers changed their usual gait significantly. The hypothesis is that the walkers do two things to improve ergonomic efficiency (the researchers call this Intelligent Human Propulsion Movement, IHPM): first, they improve their structural posture to support the heavier load; second, they unconsciously time the up-bounce to happen right when switching legs. At this point, both legs have to use energy to jerk the body’s center of gravity into the next arc. If the backpack load is headed up right about then, the weight on the legs is less, and there’s less wasted energy. However, as the investigators in Germany are finding out, this is not always an easy, natural feat-- as age and prior muscle-memory coordination play a role in the response.
The Fusion Factors of Age and Muscle Memory
For example, scientists at the Manchester Metropolitan University found out that the human body is like a car that becomes more gas guzzling with age: it needs more energy the older it gets. The exercise scientists compared the walking abilities of a group of septuagenarians (average age 74) with those of people in their late 20s and found the former using more than 30% more energy to walk 100 yards at a set speed. Professor Marco Narici, research project coordinator said: "The elderly participants had too many muscles switched on at the same time and were seeping energy like an old car with its engine out of tune. They were quite inefficient and this is due in the main to muscles overcompensating for weak joints." He said the result was that the elderly tended to take smaller, more frequent steps, and tend to drag their feet; a walking pattern that makes them more vulnerable to trips and falls. Added Professor Narici: "Exercise can help build muscle mass and strength but the fitter people still consumed the same amount of energy. This, we believe, is because the main key is the way the muscles are controlled by the nervous system and not the size or bulk of the muscles per se." Besides, no difference was found between the walking efficiency loss between men and women.
Out to Lunch
A reviewer (Arthur Kuo) points out " there is no obvious reason why the backpack cannot be improved to reduce muscle work requirements even further." (ref 1, below) The authors also remark that the backpack could run an electric fan or coolant pump for hikers’ comfort. Who knows, future Earthdance campers may jossle over who gets to wear the heavy electric pack or create a "toss the backpack around circle" when spare juice is needed!
This is no perpetual motion scam. The body still pays for the energy put out, so one might have to eat more often. Since the most average of foods has an energy density 100 times that of the best batteries, the researchers suggest that folks bring food rather than batteries. So instead of a "free lunch", the motto is "pack a lunch".
Still, one aspect lacking is the issue of storing the energy. Touting the advantages of food over batteries is one thing, but being on the march (or moving your tush to the tunes of Earthdance) to keep talking on a cellphone is quite another. However, you’ve always got the Soldius to fall back on when you’re in a laidback mood. And both approaches eliminate the need for replacement batteries, as they could keep charging the ones hikers (or dancers) left with in the first place.
Ref 3: Eady, R., Sommers F, Evolution of the Spiral Line: A fusion of Alternative Organic Transportation Energy RehaCare Congress Duessledorf, GE Oct, 2007 Presentation
Ref 4: MEDICA.de Newletter, Nov, 2006 http://www.mmu.ac.uk http://www.mmu.ac.uk/
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