Scientists develop power-generating backpack
09/09/2005
A team of biologists at the University of Pennsylvania
"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."
The 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.
"As humans walk, they vault over their extended leg, causing the hip to rise 5-7 centimetres on each step. Since the backpack is connected to the hip, it to must be lifted 5-7 centimetres,"Rome
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.
"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."
The 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.
"As humans walk, they vault over their extended leg, causing the hip to rise 5-7 centimetres on each step. Since the backpack is connected to the hip, it to must be lifted 5-7 centimetres,"
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.
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