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August 23, 2001
Giner Electrochemical Systems, LLC Delivers A Lightweight,
15-kilowatt Electrolyzer Stack For the Helios Prototype Flying Wing.
Giner Electrochemical Systems,
LLC (GES), a specialized research and development firm that develops
electrolyzers, fuel cells and related electrochemical systems, has delivered a
15 kW electrolyzer stack for the
Helios flying wing, a high altitude lightweight plane developed by NASA
and AeroVironment, Inc.
The electrolyzer stack is one
half of the regenerative power system that will keep the plane aloft for
extended flights, which will eventually last as long as six months. The
electrolyzer stack converts water, with the aid of electrical power provided by
the solar panels installed on Helios, into gaseous hydrogen and oxygen. These
reactants, when recombined into water in the power systems fuel cell stack,
provide electrical power to keep the plane flying overnight, when solar power is
unavailable. A lightweight, high-pressure fuel cell stack is currently being
tested by GES to complete the heart of the aircrafts power system.
The exciting and unique aspects
of the electrolyzer stack are its lightweight design, weighing only 23 pounds
(10.5 kg), combined with its high-pressure operation at 400 psig (2758 kPa).
The 15 kW stack consumes only 1450 watts of power per kilogram, a power to
weight ratio that was thought to be unachievable only a few years ago. The
electrolyzer stack produces nearly 4000 l/hr of hydrogen and 2000 l/hr of oxygen
for storage, and to power a fuel cell stack, completing the regenerative
system.
The electrolyzer and fuel cell
stacks are based on GES' proprietary molded graphite bipolar plate technology
and use advanced membrane-electrode assemblies (MEA’s) developed by GES. The
electrolyzer stack contains 50 cells, each operating at 1.72 volts, with 174
Amperes (1076 mA/cm2) of applied current. The electrolyzer stack has
a total volume of less than 4 liters. Operating conditions were chosen to
optimize overall system and stack efficiency.
The Helios Prototype recently
broke records by flying to an altitude of 96,863 ft (29,523 m), powered by the
sun. The planes wingspan is longer than that of a Boeing 747, weighs less than
one ton and utilizes solar power to run its 14 propellers. During the
record-breaking flight, the aircraft flew at speeds ranging from 20 mph to 170
mph (32 kph to 273 kph). Overnight test flights for the Helios are scheduled to
begin in 2003, with an initial goal of a four-day continuous flight.
The electrolyzer stack was
designed, built and tested with funding provided by NASA, Wright Patterson Air
Force Base, and AeroVironment Inc., for NASA’s Environmental Research and Sensor
Technology (ERAST) program.
See the Related Story on the
NASA website
15 kW Electrolyzer Specifications
Operating Pressures:
400 psi water, 400 psi hydrogen, 400 psi oxygen
Operating Temperature: 100 - 180 degrees Fahrenheit
Gas Production:
1973 l/hr oxygen , 3946 l/hr hydrogen
Current Density:
1000 amps/square foot
Cell Voltage:
1.72 V/cell
Contact Information:
Richard J. Lawrance, Director
(rlawrance@ginerinc.com) Phone: (781) 529-0507
Matthew P. Steinbroner, Project Manager (msteinbroner@ginerinc.com) Phone: (781)
529-0536
Giner Electrochemical Systems, LLC
Phone: (781) 529-0500; Fax: (781) 893-6470
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