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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Space power systems technology

Reported here is a series of studies which examine several potential catalysts and electrodes for some fuel cell systems, some materials for space applications, and mathematical modeling and performance predictions for some solid oxide fuel cells and electrolyzers. The fuel cell systems have a potential for terrestrial applications in addition to solar energy conversion in space applications. Catalysts and electrodes for phosphoric acid fuel cell systems and for polymer electrolyte membrane (PEM) fuel cell and electrolyzer systems were examined.

Coulman, George A.↗
NASA NTRS1995

Evaluation testing of a portable vapor detector for Part-Per-Billion (PPB) level UDMH and N2H4

Trace level detection of hydrazine (N2H4), monomethyl hydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH) has been receiving increased attention over the past several years. In May 1995 the American Conference of Government Industrial Hygienists (ACGIH) lowered their acceptable threshold limit value (TLV) from 100 parts-per-billion (ppb) to 10 ppb. Several types of ppb-level detectors are being developed by the United States Air Force (USAF) Space and Missile Systems Center (SMSC). A breadboard version of a portable, lightweight hydrazine detection sensor was developed and produced by Giner Corp. for the USAF. This sensor was designed for ppb level UDMH and N2H4 vapor detection in near real-time. This instrument employs electrochemical sensing, utilizing a three electrode cell with an anion-exchange polymer electrolyte membrane as the only electrolyte in the system. The sensing, counter and reference electrodes are bonded to the membrane forming a single component. The only liquid required to maintain the sensor is deionized water which hydrates the membrane. At the request of the USAF SMSC, independent testing and evaluation of the breadboard instrument was performed at NASA's Toxic Vapor Detection Laboratory (TVDL) for response to ppb-level N2H4 and UDMH and MMH. The TVDL, located at Kennedy Space Center (KSC) has the unique ability to generate calibrated sample vapor streams of N2H4, UDMH, and MMH over a range from less than 10 ppb to thousands of parts per million (ppm) with full environmental control of relative humidity (0-90%) and temperature (0-50 C). The TVDL routinely performs these types of tests. Referenced sensors were subjected to extensive testing, including precision, linearity, response/recovery times, zero and span drift, humidity and temperature effects as well as ammonia interference. Results of these tests and general operation characteristics are reported.

Curran, Dan↗
NASA NTRS1996

Professional Advanced Research and Analysis

Reported here is a summary of studies examining some problems in an energy conversion system. Regenerative fuel cell systems have been suggested for future manned space missions, but to meet the needed specific power requirements substantial improvements in the state-of-the-art technologies are needed. Similar improvements are needed, with emphasis on cost reduction in addition to higher conversion efficiency, for fuel cell systems that have potential for terrestrial applications. Polymer Electrolyte Membrane (PEM) fuel cells have been identified as promising candidates for development that would lead to the desired cost reduction and increased efficiency.

Coulman, George A.↗
NASA NTRS1996

Professional Advanced Research and Analysis

Reported here is a summary of studies examining some problems in an energy conversion system. Regenerative fuel cell systems have been suggested for future manned space missions, but to meet the needed specific power requirements substantial improvements in the state-of-the-art technologies are needed. Similar improvements are needed, with emphasis on cost reduction in addition to higher conversion efficiency, for fuel cell systems that have potential for terrestrial applications. Polymer electrolyte membrane (PEM) fuel cells have been identified as promising candidates for development that would lead to the desired cost reduction and increased efficiency.

Coulman, George A.↗
NASA NTRS2005

Hydrogen-Oxygen PEM Regenerative Fuel Cell Energy Storage System

An introduction to the closed cycle hydrogen-oxygen polymer electrolyte membrane (PEM) regenerative fuel cell (RFC), recently constructed at NASA Glenn Research Center, is presented. Illustrated with explanatory graphics and figures, this report outlines the engineering motivations for the RFC as a solar energy storage device, the system requirements, layout and hardware detail of the RFC unit at NASA Glenn, the construction history, and test experience accumulated to date with this unit.

Bents, David J.↗
NASA NTRS2006

Round Trip Energy Efficiency of NASA Glenn Regenerative Fuel Cell System

NASA Glenn Research Center (GRC) has recently demonstrated a Polymer Electrolyte Membrane (PEM) based hydrogen/oxygen regenerative fuel cell system (RFCS) that operated for a charge/discharge cycle with round trip efficiency (RTE) greater than 50 percent. The regenerative fuel cell system (RFCS) demonstrated closed loop energy storage over a pressure range of 90 to 190 psig. In charge mode, a constant electrical power profile of 7.1 kWe was absorbed by the RFCS and stored as pressurized hydrogen and oxygen gas. In discharge mode, the system delivered 3 to 4 kWe of electrical power along with product water. Fuel cell and electrolyzer power profiles and polarization performance are documented in this paper. Individual cell performance and the variation of cell voltages within the electrochemical stacks are also reported. Fuel cell efficiency, electrolyzer efficiency, and the system RTE were calculated from the test data and are included below.

Garcia, Christopher P.↗
NASA NTRS2002

Power generation in fuel cells using liquid methanol and hydrogen peroxide

The invention is directed to an encapsulated fuel cell including a methanol source that feeds liquid methanol (CH.sub.3 OH) to an anode. The anode is electrical communication with a load that provides electrical power. The fuel cell also includes a hydrogen peroxide source that feeds liquid hydrogen peroxide (H.sub.2 O.sub.2) to the cathode. The cathode is also in communication with the electrical load. The anode and cathode are in contact with and separated by a proton-conducting polymer electrolyte membrane.

Narayanan, Sekharipuram R.↗
NASA NTRS2008

Lunar RFC Reliability Testing for Assured Mission Success

NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated", these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development. When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

Bents, David J.↗
NASA NTRS2009

Lunar Regenerative Fuel Cell (RFC) Reliability Testing for Assured Mission Success

NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) Regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated," these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development.When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

Bents, David J.↗
NASA NTRS2009

Hydrogen Fuel System Design Trades for High-Altitude Long-Endurance Remotely- Operated Aircraft

Preliminary design trades are presented for liquid hydrogen fuel systems for remotely-operated, high-altitude aircraft that accommodate three different propulsion options: internal combustion engines, and electric motors powered by either polymer electrolyte membrane fuel cells or solid oxide fuel cells. Mission goal is sustained cruise at 60,000 ft altitude, with duration-aloft a key parameter. The subject aircraft specifies an engine power of 143 to 148 hp, gross liftoff weight of 9270 to 9450 lb, payload of 440 lb, and a hydrogen fuel capacity of 2650 to 2755 lb stored in two spherical tanks (8.5 ft inside diameter), each with a dry mass goal of 316 lb. Hydrogen schematics for all three propulsion options are provided. Each employs vacuum-jacketed tanks with multilayer insulation, augmented with a helium pressurant system, and using electric motor driven hydrogen pumps. The most significant schematic differences involve the heat exchangers and hydrogen reclamation equipment. Heat balances indicate that mission durations of 10 to 16 days appear achievable. The dry mass for the hydrogen system is estimated to be 1900 lb, including 645 lb for each tank. This tank mass is roughly twice that of the advanced tanks assumed in the initial conceptual vehicle. Control strategies are not addressed, nor are procedures for filling and draining the tanks.

Millis, Marc G.↗
NASA NTRS2006

Fuel Cell Research and Development for Future NASA Missions

NASA has been using fuel cell systems since the early days of space flight. Polymer Exchange Membrane Fuel cells provided the primary power for the Gemini and Apollo missions and more recently, alkaline fuel cells serve as the primary power source for the Space Shuttle. NASA's current investments in fuel cell technology support both Exploration and Aeronautics programs. This presentation provides an overview of NASA's fuel cell development programs.

Manzo, Michelle A.↗
NASA NTRS2011

NASA Glenn Research Center Electrochemistry Branch Battery and Fuel Cell Development Overview

This presentation covers an overview of NASA Glenn s history and heritage in the development of electrochemical systems for aerospace applications. Current developments related to batteries and fuel cells are addressed. Specific areas of focus are Li-ion batteries and Polymer Electrolyte Membrane Fuel cells systems and their development for future Exploration missions.

Manzo, Michelle A.↗
NASA NTRS2010

NASA Glenn Research Center Electrochemistry Branch Overview

This presentation covers an overview of NASA Glenn's history and heritage in the development of electrochemical systems for aerospace applications. Current programs related to batteries and fuel cells are addressed. Specific areas of focus are Li-ion batteries and Polymer Electrolyte Membrane Fuel cells systems and their development for future Exploration missions. The presentation covers details of current component development efforts for high energy and ultra high energy Li-ion batteries and non-flow-through fuel cell stack and balance of plant development. Electrochemistry Branch capabilities and facilities are also addressed.

Manzo, Michelle A.↗
NASA NTRS2011

Long-Duration Low-to Medium-Altitude Solar Electric Airship Concept

This report presents the conceptual design for a solar electric lighter-than-air, unmanned aerial vehicle, based on existing technology already reduced to practice, that could carry a 600-kg (1322-lbm) payload to altitudes up to 30 kft (9000 m), continuously maintain an airspeed up to 40 kt (21 m/sec), and remain in flight for up to 100 days. The design is based on modern nonrigid airship technology, high-strength polymer fabrics and barrier films, and previously demonstrated aerospace electrical power technology, including lightweight photovoltaics and hydrogen-air polymer electrolyte membrane (PEM) fuel cells. The vehicle concept exploits the inherent synergy between the use of hydrogen as a lifting gas and the use of hydrogen-air PEM fuel-cell technology for onboard solar energy storage. In this report, the air vehicle concept is physically characterized and its estimated performance envelope is defined

Bents, David J.↗
NASA NTRS2011

Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution

NASA requires a durable and efficient catalyst for the electrolysis of water in a polymer-electrolyte-membrane (PEM) cell. Ruthenium oxide in a slightly reduced form is known to be a very efficient catalyst for the anodic oxidation of water to oxygen, but it degrades rapidly, reducing efficiency. To combat this tendency of ruthenium oxide to change oxidation states, it is combined with iridium, which has a tendency to stabilize ruthenium oxide at oxygen evolution potentials. The novel oxygen evolution catalyst was fabricated under flowing argon in order to allow the iridium to preferentially react with oxygen from the ruthenium oxide, and not oxygen from the environment. Nanoparticulate iridium black and anhydrous ruthenium oxide are weighed out and mixed to 5 18 atomic percent. They are then heat treated at 300 C under flowing argon (in order to create an inert environment) for a minimum of 14 hours. This temperature was chosen because it is approximately the creep temperature of ruthenium oxide, and is below the sintering temperature of both materials. In general, the temperature should always be below the sintering temperature of both materials. The iridium- doped ruthenium oxide catalyst is then fabricated into a PEM-based membrane- electrode assembly (MEA), and then mounted into test cells. The result is an electrolyzer system that can sustain electrolysis at twice the current density, and at the same efficiency as commercial catalysts in the range of 100-200 mA/sq cm. At 200 mA/sq cm, this new system operates at an efficiency of 85 percent, which is 2 percent greater than commercially available catalysts. Testing has shown that this material is as stable as commercially available oxygen evolution catalysts. This means that this new catalyst can be used to regenerate fuel cell systems in space, and as a hydrogen generator on Earth.

Valdez, Thomas I.↗
NASA NTRS2012

Method and apparatus for hydrogen production from water

A method, apparatuses and chemical compositions are provided for producing high purity hydrogen from water. Metals or alloys capable of reacting with water and producing hydrogen in aqueous solutions at ambient conditions are reacted with one or more inorganic hydrides capable of releasing hydrogen in aqueous solutions at ambient conditions, one or more transition metal compounds are used to catalyze the reaction and, optionally, one or more alkali metal-based compounds. The metal or alloy is preferably aluminum. The inorganic hydride is from a family of complex inorganic hydrides; most preferably, NaBH.sub.4. The transition metal catalyst is from the groups VIII and IB; preferably, Cu and Fe. The alkali metal-based compounds are preferably NaOH, KOH, and the like. Hydrogen generated has a purity of at least 99.99 vol. % (dry basis), and is used without further purification in all types of fuel cells, including the polymer electrolyte membrane (PEM) fuel cell.

Muradov, Nazim Z.↗
NASA NTRS2019

Electrochemical Solutions for Advanced Life Support

The Oxygen Generating Assembly (OGA) on-board the International Space Station (ISS) employs a polymer electrolyte membrane (PEM) water electrolysis cell stack to electrochemically dissociate water into its two components – oxygen and hydrogen. Oxygen is provided to the cabin atmosphere for crew respiration while the hydrogen is delivered to a carbon dioxide reduction system to recover oxygen as water. The design of the OGA evolved over a number of years to arrive at the system solution that is currently operational on ISS. Future manned missions to space will require advanced technologies that eliminate the need for resupply from earth and feature in-situ resource utilization to sustain crew life and to provide useful materials to the crew. The architects planning such missions should consider all potential solutions at their disposal to arrive at an optimal vehicle solution that minimizes crew maintenance time, launch weight, installed volume and energy consumption demands. Skyre is developing new technologies through funding from NASA, the Department of Energy, and internal investment based on PEM technology that could become an integral part of these new vehicle solutions. At varying stages of Technology Readiness Level (TRL) are: an oxygen concentrator and compressor that can separate oxygen from an air stream and provide an enriched oxygen resource for crew medical use and space suit recharge without any moving parts in the pure oxygen stream; a regenerative carbon dioxide removal system featuring a PEM-based sorbent regenerator; a carbon dioxide reduction system that electrochemically produces organic compounds that could serve as fuels or as a useful intermediary to more beneficial compounds; and an electrochemical hydrogen separator and compressor for hydrogen recycle. The technical maturity of these projects is presented along with pertinent performance test data that could be beneficial in future study efforts.

Roy, Robert J.↗
NASA NTRS2003

Rod/Coil Block Copolyimides for Ion-Conducting Membranes

Rod/coil block copolyimides that exhibit high levels of ionic conduction can be made into diverse products, including dimensionally stable solid electrolyte membranes that function well over wide temperature ranges in fuel cells and in lithium-ion electrochemical cells. These rod/coil block copolyimides were invented to overcome the limitations of polymers now used to make such membranes. They could also be useful in other electrochemical and perhaps some optical applications, as described below. The membranes of amorphous polyethylene oxide (PEO) now used in lithium-ion cells have acceptably large ionic conductivities only at temperatures above 60 C, precluding use in what would otherwise be many potential applications at lower temperatures. PEO is difficult to process, and, except at the highest molecular weights it is not very dimensionally stable. It would be desirable to operate fuel cells at temperatures above 80 C to take advantage of better kinetics of redox reactions and to reduce contamination of catalysts. Unfortunately, proton-conduction performance of a typical perfluorosulfonic polymer membrane now used as a solid electrolyte in a fuel cell decreases with increasing temperature above 80 C because of loss of water from within the membrane. The loss of water has been attributed to the hydrophobic nature of the polymer backbone. In addition, perfluorosulfonic polymers are expensive and are not sufficiently stable for long-term use. Rod/coil block copolyimides are so named because each molecule of such a polymer comprises short polyimide rod segments alternating with flexible polyether coil segments (see figure). The rods and coils can be linear, branched, or mixtures of linear and branched. A unique feature of these polymers is that the rods and coils are highly incompatible, giving rise to a phase separation with a high degree of ordering that creates nanoscale channels in which ions can travel freely. The conduction of ions can occur in the coil phase, the rod phase, or both phases.

Meador, Mary Ann B.↗