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 Fuel
cells offer significant savings of loads, in weight and volume,
compared to conventional power sources. For example, a 13 pack BA-5590 batteries weigh more than 29 lbs and
cost $100 each. (Thirteen batteries are required to support a typical
72-hour deployment.) The US Army is evaluating the use of
inexpensive, injection-molded fuel cell technology formed into the common BA-5590 form factor, to power SOF PRC-117 field radio,
resulting in a weight saving of over 13 lbs and decrease its cost
by at least 50%.
Other power
sources are provided by Direct Methanol
Micro Fuel Cell (DMFC), under development at MTI
Micro. The company has already demonstrated the operation of its
power system on 100% methanol fuel resulting in 0.9 watt hours of
energy per cubic centimeters (cc) of fuel, extracting from
methanol more than three times the energy of most current lithium
ion batteries. The company is teaming with Harris RF
Communications Division, to develop a fuel cell prototype that
will replace standard batteries in Harris' Falcon II portable,
military radio. The MTI Micro-Harris prototype is currently
producing a power output of 5 watts with a peak power of 25 watts
and an energy content of greater than 50 watt hours. The fuel cell
is designed to fit into a size and form of a standard BA-5590
battery, while generating twice the energy of the radio's internal
battery, and approaching the energy of the external rechargeable
battery – the BB390.
DMFCC Introduces
Methanol Fuel Cell Cartridges
Direct Methanol
Fuel Cell Corporation (DMFCC), has completed product development
of a first methanol fuel cell cartridge. The new cartridge was
co-developed with and manufactured by DMFCC's Korean partner, SMC
Co., Ltd. Fuel cells offer longer operating time as compared to
current lithium ion batteries. With the introduction of the new
cartridges, fuel cells could be instantaneously recharged by
replacing the disposable fuel cartridge.
These fuel cell powered devices are expected to be introduced into
the marketplace by major electronic product manufacturers in 2007.
One cartridge is expected to provide five to 10 hours of computer
operation depending on the efficiency of the fuel cell. The DMFCC
methanol cartridge holds 50 cubic centimeters of 100% methanol and
is designed for a laptop computer and similar applications. Cell
phones will require smaller cartridges, and other applications may
require larger ones. DMFCC also plans to develop cartridges for
other fuels such as formic acid or ethanol, as customers require.
DMFCC focuses on producing disposable fuel cartridges containing
liquid fuels, such as methanol, to provide the energy source for
laptop computers, cell phones and other portable electronic
devices powered by direct methanol fuel cells.
Palm Power
Application
Another use of DMFC
studied by DARPA is Palm Power
program. This future portable man-packed power unit could replace
larger diesel generator sets that are currently towed on a
trailer. Palm Power will utilize compact fuel cells and thermal to
electric energy conversion technologies. Where applicable, these
power sources are also providing co-generation (producing heating,
hot water, or cooling, in addition to electricity). Fuel
chemistries considered for the program are Direct methanol
oxidation fuel cells (DMFCs). The Palm Power Program will produce
a completely packaged 20-watt direct methanol fuel cell, that,
combined with a battery, could yield a hybrid soldier power system
with significantly longer endurance than a system using batteries
alone. Typical consumers for such power cells are robots and
autonomous ground vehicles, future soldier systems, micro-air
vehicles etc. DARPA is expecting radically new approaches
developed to meet the specific energy goals of the program, which
is on the order of thousands of Whr/kg at the system level. Higher
power levels envision other approaches, including planar
solid oxide fuel cells (SOFC), thermo-photo-voltaics (TPV), alkali
metal thermal to electric converters (AMTEC), and small turbine
engines, that will operate in the 300- to 500-W range on approved
military fuels.
Vehicular Power Cell
A different fuel cell technology is considered for
an auxiliary power unit developed by Radian Inc. The system is
planned for deployment on US army vehicles. The fuel cell consists
of the Proton Exchange Membrane (PEM) technology, developed by
Hydrogenics Corp. Since modern armored
vehicles rely on the use of many electronic and electrical
systems, even when positioned in stationary positions, the APU
will offer adequate supply of electrical power, to operate digital
equipment and extended silent watch requirements. As an
alternative to the battery systems and diesel generator sets
currently being used by the military, fuel cell power generation
offers longer operation, zero emissions, improved cycle-life, low
noise signature, reduced deterioration and improved cold weather
performance. In Regenerative fuel cell technology the
system's electrolyser will recharge the hydrogen supply while the
vehicle engine is operating, supplying the hydrogen storage
subsystem with sufficient fuel to operate the fuel cell auxiliary
power system for up to ten hours at the field destination with a
load of 3 kW average, and peak demand of 5 kW.
Solid Oxide Fuel Cell Process (SOFC)
SOFC to Operate on
Military JP8 Fuel - (January 16, 2006): Gas Technology Institute (GTI)
has demonstrated operation of a high-power-density solid oxide
fuel cell (SOFC) using standard military logistics fuel (JP8)
containing 600 to 700 ppm of sulfur. This is an important
milestone on the path to developing SOFC technology providing
efficient, clean, and quiet power for military applications.
The process uses steam reforming process that prepares the gas for
the SOFC stack, enabling effective thermal management which is key
for the system's efficiency. The JP8 fuel processor uses an
advanced sulfur tolerant catalyst, novel JP8 burner, and radiant
heat transfer system to convert JP8 military logistics fuel into
hydrogen and other SOFC fuel gases. This JP8 fuel processor has
operated stably for 600 hours of testing to date. The overall
system is designed to capture and recycle water so that it can
operate without an external water supply.
The planar SOFC stack was supplied by Versa Power Systems (VPS).
It is built of twenty-one cell stack, producing about 800 watts
from JP8 processing, with an impressive power level of 315 mW/cm2.
The next generation demonstration system will use advanced SOFC
stacks to achieve the 3 to 10 kW power goal - suitable to meet the
military's Mobile Electric Power (MEP) generation requirements.
The work is funded through the U.S. Department of Defense under
the U.S. Army Engineer Research and Development Center's
Construction Engineering Research Laboratory (ERDC-CERL).
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