Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shoe leather as a renewable resource: Penn biologists invent power-generating backpack

09.09.2005


If you already have a little spring in your step, a team of biologists at the University of Pennsylvania would like to them to good use by adding a few more springs in the form of a power-generating backpack. Details of their prototype "Suspended-load Backpack" were announced today in the journal Science. The device converts mechanical energy from walking into electricity – up to 7.4 Watts – more than enough energy to power a number of portable electronic devices at once.



"As efficient as batteries have gotten, they still tend to be heavy.

Field researchers, for example, have to carry many replacement batteries to power their equipment, which take up a lot of weight and space in the pack," said Larry Rome, a professor in Penn’s Department of Biology. "The Suspended-load Backpack could help anyone with a need for power on the go, including researchers, soldiers, disaster relief-workers or someone just looking to keep a mobile phone charged during a long trek."


Although "biologist" might seem like an unlikely job title for a mechanical inventor, Rome has found his study of muscular systems of locomotion to be directly applicable to the work. During the war in Afghanistan, the Office of Naval Research approached Rome to develop a means to assist over-burdened soldiers who must carry as much as 20 pounds of spare batteries required to power high-tech equipment such as global positioning systems, communications and night vision devices. A typical soldier already marches into the battlefield carrying 80 pounds of gear, so Rome sought a way to capture the mechanical energy of marching in order to charge a lightweight rechargeable battery that could replace all the spares.

The Suspended-load Backpack is based on a rigid frame pack, much like the type familiar to hikers everywhere; however, rather than being rigidly attached to the frame, the sack carrying the load is suspended from the frame by vertically oriented springs. It is the vertical movement of the backpack contents that provides the mechanical energy to drive a small generator mounted on the frame. Previous efforts to solve dilemma of the over-burdened soldier incorporated devices placed in the heels of boots. According to Rome, however, little mechanical work is actually done at the point where the boots hit the ground.

"As humans walk, they vault over their extended leg, causing the hip to rise 5-7 centimeters on each step. Since the backpack is connected to the hip, it to must be lifted 5-7 centimeters," Rome said. "It is this vertical movement of the backpack that ultimately powers electricity generation."

The amount of power generated depends on how much weight is in the pack and how fast the wearer walks. The Penn researchers tested packs with loads of 40 to 80 pounds and found that the wearer could constantly generate as much as 7.4 Watts while moving at a steady clip. Typically, cell phones – or even night vision goggles – require less than one Watt to power.

Contrary to what might be expected, wearing the Suspended-load Backpack does not use up much more metabolic energy than walking while wearing a conventional backpack of the same weight. According to Rome and his colleagues, it is likely that wearers can change their stride to compensate for movement of the load, which makes walking more efficient.

"Metabolically speaking, we’ve found this to be much cheaper than we anticipated. The energy you exert could be offset by carrying an extra snack, which is nothing compared to weight of extra batteries," Rome said. "Pound for pound, food contains about 100-fold more energy than batteries."

Greg Lester | EurekAlert!
Further information:
http://www.upenn.edu

More articles from Power and Electrical Engineering:

nachricht Energy hybrid: Battery meets super capacitor
01.12.2016 | Technische Universität Graz

nachricht Tailor-Made Membranes for the Environment
30.11.2016 | Forschungszentrum Jülich

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>