Advanced Regenerative Fuel Cell System for High-Altitude Airships
Summary:
MDA-funded Giner Electrochemical Systems is developing a regenerative fuel-cell system that will replenish used fuel by capturing product water from the fuel cell and processing the water to transform it back into hydrogen and oxygen. MDA originally funded Giner through a Phase II SBIR award to develop an advanced regenerative fuel-cell system for possible use in the High Altitude Airship (HAA) program. Giner continues system development for its technology, which could prove useful in space vehicles or space stations, as well as the automobile and energy industries.
Technology Description:
Giner is developing a regenerative fuel-cell system incorporating a 15-kilowatt electrolyzer and a 5-kilowatt fuel cell. The advanced electrolyzer weighs only 16 kilograms. The system will replenish the fuel in a fuel cell by capturing product water from the cell and processing the water into its elemental components: hydrogen and oxygen. (Note: Normally, providing oxygen for use in a fuel cell involves pulling oxygen from the air. In the vacuum of space or at a high altitude, however, the oxygen has to come from other sources.) The process by which the water is broken down into hydrogen and oxygen is known as electrolysis, and Giner is developing a special solar-powered electrolyzer appropriate for high-altitude or even space-based applications.
Giner researchers are developing what they hope will be a truly “closed loop” system, with extremely minimal loss of reactants (hydrogen, oxygen, water). The system’s only losses should occur through the natural permeability of valves and materials, according to the company. Typically, users do not capture the water that is produced as a byproduct of fuel cells. But at high altitudes, where oxygen is scarce and sunlight plentiful, the water could be used to produce oxygen and hydrogen, which in turn could be used again in the fuel cell to create power.
Compared with lithium-ion batteries—a potential competitor to fuel cells in high-altitude applications—Giner’s system will offer greater energy density. (Energy density is the amount of energy per unit of weight.) Lithium-ion batteries have an energy density of about 200 watt-hours per kilogram. But Giner’s regenerative fuel-cell system should have energy density greater than 600 watt-hours per kilogram. Long-duration flights—such as high-altitude airship missions—will require power systems capable of at least 600 watt-hours per kilogram, according to Giner.
Creating the new fuel-cell system has required Giner to address issues such as a lack of readily available sensing technologies—a lack of hydrogen-in-oxygen sensors and oxygen-in-hydrogen sensors, for example. The company has performed engineering workarounds to meet the challenges. Giner researchers also want to ensure that when the final device operates, it switches smoothly between fuel-cell operations and electrolyzer operations.
Giner continues system development and seeks new materials that will help decrease the weight of the system and ancillary components—such as lighter valves and pumps, as well as higher-pressure pumps. Getting near-zero loss of reactants also will remain a focus.
MDA Origins:
MDA originally funded Giner through a Phase II SBIR award to develop an advanced regenerative fuel-cell system for possible use in the High Altitude Airship (HAA) program. The HAA project seeks to put in place unmanned, untethered, lighter-than-air high-altitude airships that can be used in ballistic missile defense. Providing adequate power for the airship and payloads is a prime concern for long-duration HAAs.
Regenerative fuel cell (RFC) systems are a promising alternative to secondary batteries for power systems that must be lightweight, have a long cycle life, and have high reliability. In the Phase I program, Giner demonstrated a unitized RFC having a round-trip efficiency of greater than 48 percent and developed a preliminary design for a closed-loop RFC system. The Phase II program sought to advance RFC technology by demonstrating a completely closed-loop RFC system with production and storage of hydrogen and oxygen at elevated pressure.
Spinoff Applications:
Giner’s work could lead to more wide-ranging improvements in fuel-cell and electrolyzer technologies. The emerging technology also should draw interest from designers of space vehicles or space stations, as well as the automobile and energy industries. Giner officials have suggested that some innovations being pursued under the MDA project could eventually prove useful for fuel-cell-powered cars.
Giner officials say that the RFC system developed in this program will benefit other HAAs and unmanned aerial vehicles, both for governmental and commercial applications. There is a large commercial market for RFCs for premium back-up power applications, such as telecommunication towers and computer servers, according to Giner.
Commercialization:
The company continues to develop the technology and so far has not ventured toward commercialization with this product. However, the company is expecting any final product to be competitive with existing and emerging electrolyzers. For example, one discriminating feature of Giner’s technology will be weight. The electrolyzer that the company is developing should weigh in at about half the weight of current state-of-the-art electrolyzers. Still, Giner’s emerging technology would have to compete with other emerging power solutions, such as new types of batteries.
Giner continues system development and seeks new materials that will help decrease the weight of the system and ancillary components—such as lighter valves and pumps, as well as higher-pressure pumps. Getting near-zero loss of reactants also will remain a focus.
Company Profile:
Giner Electrochemical Systems and an affiliated company (called Giner, Inc.) currently employ approximately 50 people, of whom 12 hold Ph.D. degrees in the physical sciences or engineering, and 6 hold M.S. degrees. Giner employees have over 500 person-years combined experience in the development of proton-exchange-membrane electrochemical-conversion technology and products. They also have more than 100 U.S. patents issued to them in the field of electrochemistry. Of the two companies in the Giner family, Giner Electrochemical Systems applies membrane technology to fuel cells for power generation, high-pressure electrolyzers for regenerative power, hydrogen fuel production, and oxygen production for life support. Meanwhile, Giner, Inc., focuses proton-exchange-membrane technology on electrochemical sensors and biomedical devices such as self-contained transdermal alcohol sensors and environmental gas sensors.
Contact Information:
Tony Vaccaro
Giner Electrochemical Systems, LLC
89 Rumford Avenue
Newton, MA 02466-1311
Tel: (781) 529-0506
web: www.ginerinc.com
email: avaccaro@ginerinc.com
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