Momentum - The Magazine for Virginia Tech Mechanical Engineering Vol. 1 No. 3 | Page 14

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Faculty member gets separate grants
for energy harvesting research
Backpack feature will allow
soldiers to recharge batteries
and new system will allow for
monitoring storage containers

Backpacks

United States Army soldiers on 72-hour missions
sometimes carry seven types of batteries weighing
up to 16 pounds in order to operate night vision
goggles, communications, and GPS equipment. But
by using innovative technology designed by Virginia
Tech researchers, soldiers will soon have a lighter,
more energy-efficient load to bear.
An Army grant of more than $344,000 has been
awarded to Lei Zuo, associate professor and John R.
Jones III Faculty Fellow of Mechanical Engineering,
to create a backpack energy harvester.
The technology, which is expected to weigh about
one pound with a harvesting capacity of 5-20 watts,
will lead to lighter packs for military members,
decreased supply chain requirements, and fewer
muscular and skeletal injuries caused by heavy
packs, improving the overall health of the soldier.
“By using mechanical motion rectifier (MMR), a
technology converting oscillatory vibration motion
into unidirectional rotation and scaling it down, we
will work to create a device that sits on the frame
of a soldier’s pack and harvests energy to recharge
batteries as the soldier walks,” said Zuo. “This work
builds on my previous work in energy harvesting.”
In the same way that ocean waves drive the MMR
as they approach and depart an ocean energy-harvesting buoy, the backpack technology works to
gather power as a soldier’s pack moves up and
down as the soldier walks, with the multidirectional
motion of walking converted into the unidirectional
rotation of a generator.

“Because the generator rotates at a steady speed
with higher efficiency, it provides higher energy conversion efficiency and enhanced reliability over packs
with conventional rack pinion systems,” Zuo said.
“More important, the MMR motion will change the
dynamics of a suspended backpack and enable it to
harvest more electricity with less human metabolic
cost.”
The harvester will be developed and tested at Virginia Tech during the first year of the project and integrated into the backpack for testing and demonstrations
at the Army Communications-Electronics Research,
Development, and Engineering Center in the second
year.

Monitoring

$1M DOE grant to monitor
inside spent fuel rod containers
In a separate grant, Zuo was awarded a DOE Nuclear Engineering research grant to develop nuclear
radiation energy harvesting and through-wall wireless
communication for enclosed metal containers in
nuclear environments, like pressure reactor vessels or
nuclear spent-fuel canisters.
With the $1 million grant from the Department of
Energy, Zuo is putting his energy harvesting research to
use to create a way to monitor the contents of storage containers used for spent nuclear fuel rods. The
containers, which typically include one-half inch metal
shells, aren’t suited for standard wireless technology;
and, because of their contents, holes can't be drilled
into them for power or data cables. Zuo’s approach to
the problem is novel.
“To provide in-situ monitoring of the interior conditions of enclosed metal or thick concrete canisters,
we are building a system that will use the gamma and
beta radiations found within the canisters themselves,”
said Zuo, who is the John R. Jones III Faculty Fellow of
Mechanical Engineering. “Then we will use ultrasound
transmission to deliver temperature, humidity, and