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Crowd Farm II: Piezoelectricity Potential

| Friday November 16th, 2007 | 3 Comments

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The article on Crowd Farms has generating a stirring debate and a lot of interest so I figured I would follow up with a piece that highlights some more applications of this concept of people and motion creating power. The problem with the Crowd Farm plan is it only exists on paper and could be too costly for production, but that is how many great ideas begin in my opinion. Take solar for example, solar panels used to cost some $20 per watt to produce in the early 80’s and now Nanosolar has reduced this cost to below that of coal energy at 30 cents per watt. Some great ideas take time, money and significant effort to produce real-world applications. Finding a balance of how much to leech off a person’s movement is the most difficult problem for human-powered technology. All energy has to come from somewhere which means that if you are the one producing the power then, to some degree, you’re the one feeling the drain.


A prototype of the crowd farm has already been tested in a railway station in Turin, Italy. Also, a select number of Japanese train stations are currently generating small quantities of electricity by capturing the motion through turn-styles at the ticket hub as commuters pass through them. The developers of the crowd farm hope to not just draw power from people, they want to also raise people’s awareness of the vast quantities of electricity that they consume each day in various forms: “We want people to understand the direct relationship between their movement and the energy produced,” stated Thaddeus Jusczyk, co-creator of the MIT’s crowd farm. The idea has many large obstacles to overcome for it is not possible to install the technology in existing buildings which have traditional floorings. As such, crowd farms need to be developed much further before they can become economically viable. James Graham is quoted as saying that “only through experimentation, which can be expensive, can this technology become practical.”
In both of these cases, as in the case of solar energy, the overriding question might be, “that’s great, but how much money do you have to spend to capture the energy, so that you can calculate the cost per watt.” If it’s inexpensive, then projects like these move ahead at great speed.
The concept of people providing power is being explored in various ways. The keyword here is piezoelectricity or the science of harnessing power from mechanical stress, including motion.
Although the crowd-farm concept is generating a lot of critics I personally support new and inventive ideas because it can spin itself into something else entirely that can be very practical and useful in the end. Some ideas begin with a seed that is believed it will grow to be just another weed when in reality it develops into a plant that changes its surrounding environment for the better. The discipline of the concept of people providing power is growing and the corporate world is jumping on board.
“This is a really exciting time because there’s been a lot of growth all of a sudden,” says Steve Anton, whose review article on recent piezoelectric advances ran in the June issue of the journal Smart Materials and Structures. “For a long time the research was confined to the lab, but a number of real applications have started coming out.”
Gym Power Plants
Human powered Gyms in Hong Kong. The research indicates that one person has the capacity to produce 50 watts of electricity per hour when exercising at a moderate pace. A dedicated gym rat running one hour per day on a power generating treadmill could generate 18.2 kilowatts of electricity and prevent 4,380 liters of CO2 released per year.
POWERLeap
An example is POWERLeap created by a sustainable designer Elizabeth Redmond. It is essentially a scaled-down version of the crowd farm concept. When pedestrians walk across a sidewalk in Ann Arbor, Michigan, four decorated glass tiles containing LED lights light-up beneath their feet. The power is generated by the movement and pressure of the people’s feet on the tiles. Redmond is now working on a more in depth design for POWERLeap thanks in part to a grant from the flooring behemoth Mohawk Industries.
Micro Body Generators
Some piezoelectric engineers have found promising ways to feed off human motion. A consortium of companies is scheduled to release an in-body microgenerator that will convert energy from joint movements, heartbeats, and breathing by the end of the year. The tiny power generator will help both decrease the size and extend the life of batteries attached to pacemakers and other critical medical instruments in turn saving patients from costly invasive replacements.
Powered Backpacks
Human energy can also be harnessed to power your electronics or charge a battery. Henry Sodano, an engineering professor at ASU in Tempe, Arizona, has developed a backpack that can power up your cell phone or gadgets. He has created piezoelectric straps that draw power from the backpack’s natural rising and falling cadence when in motion. At a normal stride, the stress on the bands can produce 45.6 milliwatts (mW). This is just a short of the required energy to perpetually power an iPod nano but more than enough to keep a Motorola Razr mobile phone charged.
“We could power a Razr in standby using 9mW of power and store the remaining 36.6mW of power, allowing us to talk for one minute for every 10 minutes walked,” he says. “Or you could charge an LED headlamp while you walk in the day and use it at night while you camp.”
The big downside to this early model is for the straps to collect the full 45.6mW, they need to support a 100-pound backpack. That is far too heavy compared to the average load of the average highschool or college student. But the straps have been designed for the US military to use. Since some soldiers find themselves carrying heavy loads, the special straps in their packs will capture the energy that their duties produce.
Powered Shoes
Mr. Anton, a graduate student at Virginia Tech, plans to unveil a new shoe design in October that places a piezoelectric charger in a box above the heel. This will add weight, he says, but eliminate the deflating feel and additional energy spent from the taxing sole-based prototypes.
Watches
“Automatic” watches have been around for some time and work because they are so light to begin with that the added weight of the self-winding mechanism is not enough to deter consumers. However, watches also require very little power.
“To get anything substantial out of these devices, they would have to weigh a ton, and that’s something few consumers will agree to,” says Peter Glas¬¨kowsky, a technology analyst for Envisioneering. “The energy you’re saving by not using batteries is actually coming from you, and therefore it’s coming from food. If you add up the energy used to grow, package, ship, and eat, food is an extremely inefficient energy source.”
Self-Powered Laptop
Another worthy note, the “One Laptop per Child Foundation” scrapped their plan to yield power via an auxiliary hand crank on the side of its “$100 laptops,” realizing the effort was not worth the power it provided. They then turned their eye to a “yo-yo” pull-cord charger which also failed to be practical in the end and have instead leaned toward using solar for power.


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  • Anonymous

    Looks like someone in the Netherlands is on to this! LINK HERE

  • Lee

    I think its a neat idea. The floors and stairways in our homes could be converted for energy independence. How about something similar using the highway as the traffic rolls over it? It opens a whole new view of energy production. Like perhaps pushing a turnstile will be the new gym work out. Its all so interesting. . .

  • suresh kumar

    i want more details about piezo shoes and watches for my piezo electric project