RICHLAND, Wash. -— When 21st century soldiers suit up for the battlefield in helmets featuring image displays and laser range finders, one of their most important accessories may be a new power generator so lightweight a soldier can carry it with him. The "man-portable generator" is being developed at the Department of Energy's Pacific Northwest National Laboratory for the U.S. Army's Communications-Electronics Command.
The Army faces an increased demand for power as it pursues futuristic cyber systems for soldiers, such as heads-up displays and global-positioning systems. The man-portable generator would supply the power needed for these advanced technologies by generating 15 to 25 watts of power inside a system weighing 10 times less than batteries soldiers currently carry. The increased power density would allow soldiers to either reduce their load or greatly extend their missions.
In March, PNNL engineers reached the first major milestone in development when they demonstrated a full-size, advanced design fuel processor that converts methanol into hydrogen. Because hydrogen wouldn't need to be stored or carried, the fuel processor would reduce the weight and risk associated with portable power systems.
"We've taken a significant step toward light-weight power generation with this breadboard-stage fuel processor," said Ed Baker, PNNL project manager, referring to the development stage between creating a proof-of-concept and a prototype system. "Our system produces the hydrogen that fuel cells need to create power. We expect to create hydrogen from liquid fuels such as methanol, synthetic diesel and possibly military jet fuels. Each of these is more readily available and easier to carry than hydrogen."
Based on the encouraging results of the breadboard-stage development, PNNL engineers are designing a prototype fuel processor and hope to have it tested within the next year. Then, they will face the challenge of integrating it with other components of a complete power system, including a micro-scale fuel cell, a fuel storage and a delivery unit, and a battery for peak power. They hope to have the complete power system ready for testing by 2003.
"By then, we expect infantry soldiers to use a variety of electronic gear, such as heads-up displays, global positioning systems, laser range finders and thermal weapons sights," said James Stephens, team leader for fuel cell technology with the Army. "Integrated computer and communications devices will allow the soldier to be aware of their location, as well as that of fellow soldiers. The net result will be a significant improvement in their capabilities.
"It all takes power, but we can't ask these soldiers to carry any more weight."
Weight would be reduced dramatically—the man-portable generator would weigh as little as two pounds. The best lithium batteries currently available would have to weigh as much as 20 pounds to provide equivalent power for one week. And, the generator's fuel processor allows the system to be refueled so it can be used again. In addition to the reduction in weight, engineers at the Army and the laboratory expect the portable generator to be less expensive than batteries.
PNNL engineers based the fuel processor design on 1- to 10-kilowatt prototypes they have built for use in automobile power systems. The processor being developed for the man-portable generator consists of four micro-technologies: a combustor, vaporizer, primary conversion reactor and a gas cleanup device. It uses a proprietary catalyst to produce hydrogen from hydrocarbon fuels. Reactions take place within small channels of a catalytic converter. These micro-channels enhance heat and mass transfer rates and significantly speed up chemical reactions, which reduces the device's size.
The laboratory's microtechnology group is well recognized for its efforts to miniaturize chemical and thermal systems, and it won two R&D 100 awards in 1999.
"Our scientists are pioneers in the microtechnology field," said Terry Doherty, who manages the laboratory's Army-funded research. "The man-portable generator is a natural next step as we apply this expertise to portable power issues."
Business inquiries on this or other PNNL technologies should be directed to 1-888-375-PNNL or e-mail: [email protected] More information on the laboratory's microtechnology research is available at http://www.pnl.gov/microcats/.
Pacific Northwest National Laboratory is a DOE research facility and delivers breakthrough science and technology in the areas of environment, energy, health, fundamental sciences and national security. Battelle, based in Columbus, Ohio, has operated the laboratory for DOE since 1965.
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