Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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


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:

More articles from Power and Electrical Engineering:

nachricht Neutrons pave the way to accelerated production of lithium-ion cells
20.03.2018 | Technische Universität München

nachricht Monocrystalline silicon thin film for cost-cutting solar cells with 10-times faster growth rate fabricated
16.03.2018 | Tokyo Institute of Technology

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: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Earlier flowering of modern winter wheat cultivars

20.03.2018 | Agricultural and Forestry Science

Smithsonian researchers name new ocean zone: The rariphotic

20.03.2018 | Life Sciences

Molecular doorstop could be key to new tuberculosis drugs

20.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>