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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 55 records · Page 3

Spray Bar Zero-Gravity Vent System for On-Orbit Liquid Hydrogen Storage

During zero-gravity orbital cryogenic propulsion operations, a thermodynamic vent system (TVS) concept is expected to maintain tank pressure control without propellant resettling. In this case, a longitudinal spray bar mixer system, coupled with a Joule-Thompson (J-T) valve and heat exchanger, was evaluated in a series of TVS tests using the 18 cu m multipurpose hydrogen test bed. Tests performed at fill levels of 90, 50, and 25 percent, coupled with heat tank leaks of about 20 and 50 W, successfully demonstrated tank pressure control within a 7-kPa band. Based on limited testing, the presence of helium constrained the energy exchange between the gaseous and liquid hydrogen (LH2) during the mixing cycles. A transient analytical model, formulated to characterize TVS performance, was used to correlate the test data. During self-pressurization cycles following tank lockup, the model predicted faster pressure rise rates than were measured; however, once the system entered the cyclic self-pressurization/mixing/venting operational mode, the modeled and measured data were quite similar. During a special test at the 25-percent fill level, the J-T valve was allowed to remain open and successfully reduced the bulk LH2 saturation pressure from 133 to 70 kPa in 188 min.

Hastings, L. J.↗

Radiation Shielding Materials Containing Hydrogen, Boron, and Nitrogen: Systematic Computational and Experimental Study

The key objectives of this study are to investigate, both computationally and experimentally, which forms, compositions, and layerings of hydrogen, boron, and nitrogen containing materials will offer the greatest shielding in the most structurally robust combination against galactic cosmic radiation (GCR), secondary neutrons, and solar energetic particles (SEP). The objectives and expected significance of this research are to develop a space radiation shielding materials system that has high efficacy for shielding radiation and that also has high strength for load bearing primary structures. Such a materials system does not yet exist. The boron nitride nanotube (BNNT) can theoretically be processed into structural BNNT and used for load bearing structures. Furthermore, the BNNT can be incorporated into high hydrogen polymers and the combination used as matrix reinforcement for structural composites. BNNT's molecular structure is attractive for hydrogen storage and hydrogenation. There are two methods or techniques for introducing hydrogen into BNNT: (1) hydrogen storage in BNNT, and (2) hydrogenation of BNNT (hydrogenated BNNT). In the hydrogen storage method, nanotubes are favored to store hydrogen over particles and sheets because they have much larger surface areas and higher hydrogen binding energy. The carbon nanotube (CNT) and BNNT have been studied as potentially outstanding hydrogen storage materials since 1997. Our study of hydrogen storage in BNNT - as a function of temperature, pressure, and hydrogen gas concentration - will be performed with a hydrogen storage chamber equipped with a hydrogen generator. The second method of introducing hydrogen into BNNT is hydrogenation of BNNT, where hydrogen is covalently bonded onto boron, nitrogen, or both. Hydrogenation of BN and BNNT has been studied theoretically. Hyper-hydrogenated BNNT has been theoretically predicted with hydrogen coverage up to 100% of the individual atoms. This is a higher hydrogen content than possible with hydrogen storage; however, a systematic experimental hydrogenation study has not been reported. A combination of the two approaches may be explored to provide yet higher hydrogen content. The hydrogen containing BNNT produced in our study will be characterized for hydrogen content and thermal stability in simulated space service environments. These new materials systems will be tested for their radiation shielding effectiveness against high energy protons and high energy heavy ions at the HIMAC facility in Japan, or a comparable facility. These high energy particles simulate exposure to SEP and GCR environments. They will also be tested in the LaRC Neutron Exposure Laboratory for their neutron shielding effectiveness, an attribute that determines their capability to shield against the secondary neutrons found inside structures and on lunar and planetary surfaces. The potential significance is to produce a radiation protection enabling technology for future exploration missions. Crew on deep space human exploration missions greater than approximately 90 days cannot remain below current crew Permissible Exposure Limits without shielding and/or biological countermeasures. The intent of this research is to bring the Agency closer to extending space missions beyond the 90-day limit, with 1 year as a long-term goal. We are advocating a systems solution with a structural materials component. Our intent is to develop the best materials system for that materials component. In this Phase I study, we have shown, computationally, that hydrogen containing BNNT is effective for shielding against GCR, SEP, and neutrons over a wide range of energies. This is why we are focusing on hydrogen containing BNNT as an innovative advanced concept. In our future work, we plan to demonstrate, experimentally, that hydrogen, boron, and nitrogen based materials can provide mechanically strong, thermally stable, structural materials with effective radiation shielding against GCR, SEP, and neutrons.

Radiation↗

Energy Efficient Large-Scale Storage of Liquid Hydrogen

The world’s largest liquid hydrogen storage tanks were constructed in the mid-1960sat the NASA Kennedy Space Center. These two vacuum-jacketed, perlite powder insulated tanks, still in service today, have 3,200 m3 of useable capacity. In 2018, construction began on an additional storage tank at Launch Complex 39B. This new tank will give an additional storage capacity of 4,700 m3 for a total on-site storage capacity of roughly 8,000 m3. NASA’s new Space Launch System (SLS) heavy lift rocket for the Artemis program includes an LH2tank that makes up the bulk of the vehicle, holding 2,033 m3 of LH2 in its 8.4-m diameter by40-m height. The new storage tank includes two new energy-efficient technologies: a glass bubbles insulation system in lieu of perlite, and an Integrated Refrigeration and Storage (IRAS)heat exchanger for controlled storage capability. The evacuated glass bubbles insulation system is based on the prior two decades of research to prove the thermal performance benefits as well as the mechanical and vacuum integrity; and has been shown to reduce LH2 boiloff by 46%versus perlite in field demonstrations. The IRAS capability is centered on a heat exchanger system that is built within the inner vessel to reject heat from the bulk liquid through the future implementation of an external helium refrigerator. Controlled storage via IRAS, when fully implemented, will provide full control of the ullage pressure, zero boiloff, and even production of densified LH2 pending its adoption on future launch vehicles. The design basics are described along with main construction and testing processes involved. The key features of the new technology items and implications on simplified operations and long-term energy savings are addressed

cryogenics↗

The Role of Water in the Storage of Hydrogen in Metals

One major problem with the use of hydrogen is safe and efficient storage. In the pure form, bulky and heavy containers are required greatly reducing the efficiency of its use. Safety is also a great concern. Storage of hydrogen in the form of a metal hydride offers distinct advantages both in terms of volumetric efficiency and in terms of safety. As a result, an enormous amount of research is currently being done on metal-hydrogen systems. Practical application of these systems to storage of hydrogen can only occur when they are very well understood. In this paper, the preliminary results of a study of the surfaces of magnesium nickel alloys will be presented. Alloys that have been rendered totally unreactive with hydrogen as well as those that have been activated with liquid water and with water vapor were studied. Data obtained from XPS (X-ray Photoelectron Spectrometer) analysis, with samples held in vacuum for the shortest possible time to minimize the hydroxide degradation will be presented. Furthermore, TEM data on samples prepared in a new way that largely protects the surface from the high vacuum will be discussed.

Hampton, Michael D.↗

System for operating solid oxide fuel cell generator on diesel fuel

A system is provided for operating a solid oxide fuel cell generator on diesel fuel. The system includes a hydrodesulfurizer which reduces the sulfur content of commercial and military grade diesel fuel to an acceptable level. Hydrogen which has been previously separated from the process stream is mixed with diesel fuel at low pressure. The diesel/hydrogen mixture is then pressurized and introduced into the hydrodesulfurizer. The hydrodesulfurizer comprises a metal oxide such as ZnO which reacts with hydrogen sulfide in the presence of a metal catalyst to form a metal sulfide and water. After desulfurization, the diesel fuel is reformed and delivered to a hydrogen separator which removes most of the hydrogen from the reformed fuel prior to introduction into a solid oxide fuel cell generator. The separated hydrogen is then selectively delivered to the diesel/hydrogen mixer or to a hydrogen storage unit. The hydrogen storage unit preferably comprises a metal hydride which stores hydrogen in solid form at low pressure. Hydrogen may be discharged from the metal hydride to the diesel/hydrogen mixture at low pressure upon demand, particularly during start-up and shut-down of the system.

Singh, Prabhu↗

Techno-Economic Analysis of Green Hydrogen Energy Storage in A Cryogenic Flux Capacitor

The Cryogenic Flux Capacitor (CFC) is a cold, dense energy storage core that is being studied in the cryo-compressed, about 300 bar and 80K, region of gaseous hydrogen (GH 2 ) storage and liquid hydrogen (LH 2 ) region near the normal boiling point. Hydrogen storage is improved by physically bonding the molecules within the nanoscale pores of the aerogel composite blanket material. The process of bonding or debonding is governed by principles of physical adsorption (physisorption) and thermodynamics. The large surface area afforded by the nanoporous aerogel (~1,000 m 2 /g) allows its storage performance to easily exceed capacities of high-pressure GH 2 storage for an equivalent volume. With the integrated aerogel, subscale tests have shown that storage is increased by about 36% over a simple tank filled with GH 2 at the same operating temperature and pressure. For LH 2 conditions, the CFC is shown to operate at improved densities, but testing is ongoing. For the techno-economic analysis (TEA), the source of hydrogen is compared between onsite steam methane reforming (SMR) and onsite solar photovoltaic (PV) panels providing power to electrolyzers to produce green GH 2 . The TEA compares pure hydrogen produced at a small scale for a 25 MW power system and at a large scale in a 500 MW power system. The system allowed for hydrogen imports and exports at a set price with a tank sized for 10 hours of power production. The two power producing technologies are a combined cycle gas turbine (CCGT) and hydrogen fuel cells. The SMR system uses natural gas as an input and includes a carbon capture and storage (CCS) system. The levelized cost of electricity (LCOE), levelized cost of hydrogen (LCOH), and levelized cost of storage (LCOS) are developed based on the capital cost and operating cost of the systems. The results are shown for current costs using a 2021 benchmark and DOE projections for cost improvements by 2030. The TEA showed that onsite hydrogen generation from SMR has an LCOH of about 1.4 to 2 USD per kg over the life of the plant and the PV hydrogen production LCOH is about 5.2 to 5.5 USD per kg. The LCOS of conventional GH 2 systems is estimated to be $210/MWh and cost of storage for LH 2 systems is $205/MWh for fuel cell systems and $249/MWh for CCGT systems. CFC improved the LCOS of all these systems to $198/MWh, $191/MWh and $233/MWh respectively. The LCOE also improved with conventional systems between $171/MWh and $228/MWh improved by CFC to between $167/MWh and $212/MWh. Using projections for improvement in costs following DOE’s goals by 2030, green hydrogen improved to as low as $78/MWh LCOS and LCOE for conventional cases. CFC improved over conventional storage with the lowest LCOS being $62/MWh and the lowest LCOE being $73/MWh. These results correspond to an LCOH of $2/kg. Finally, the TEA shows how LCOE is improved for hydrogen conditioning and storage over conventional systems and caverns in the 10 to 50 hour range.

Joshua Schmitt↗

Hydrogen Research for Spaceport and Space-Based Applications: Hydrogen Production, Storage, and Transport

The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Hydrogen storage and in-space hydrogen transport research focused on developing and verifying design concepts for efficient, safe, lightweight liquid hydrogen cryogenic storage systems. Research into hydrogen production had a specific goal of further advancing proton conducting membrane technology in the laboratory at a larger scale. System and process trade studies evaluated the proton conducting membrane technology, specifically, scale-up issues.

Anderson, Tim↗

ERDA's Chemical Energy Storage Program

The Chemical Energy Storage Program is described with emphasis on hydrogen storage. Storage techniques considered include pressurized hydrogen gas storage, cryogenic liquid hydrogen storage, storage in hydride compounds, and aromatic-alicyclic hydrogen storage. Some uses of energy storage are suggested. Information on hydrogen production and hydrogen use is also presented. Applications of hydrogen energy systems include storage of hydrogen for utilities load leveling, industrial marketing of hydrogen both as a chemical and as a fuel, natural gas supplementation, vehicular applications, and direct substitution for natural gas.

Swisher, J. H.↗

Diagnosis of a Poorly Performing Liquid Hydrogen Bulk Storage Sphere

There are two 850,000 gallon Liquid Hydrogen (LH2) storage spheres used to support the Space Shuttle Program; one residing at Launch Pad A and the other at Launch Pad B. The LH2 Sphere at Pad B has had a high boiloff rate since being brought into service in the 1960's. The daily commodity loss was estimated to be approximately double that of the Pad A sphere, and well above the minimum required by the sphere's specification. Additionally, after being re-painted in the late 1990's a "cold spot" appeared on the outer sphere which resulted in a poor paint bond, and mold formation. Thermography was used to characterize the area, and the boiloff rate was continually evaluated. All evidence suggested that the high boiloff rate was caused by an excessive heat leak into the inner sphere due to an insulation void in the annulus. Pad B was recently taken out of Space Shuttle program service which provided a unique opportunity to diagnose the sphere's poor performance. The sphere was drained and inerted, and then opened from the annular relief device on the top where a series of boroscoping operations were accomplished. Boroscoping revealed a large Perlite insulation void in the region of the sphere where the cold spot was apparent. Perlite was then trucked in and off-loaded into the annular void region until the annulus was full. The sphere has not yet been brought back into service.

Krenn, Angela G.↗

Review of Current State of the Art and Key Design Issues With Potential Solutions for Liquid Hydrogen Cryogenic Storage Tank Structures for Aircraft Applications

Due to its high specific energy content, liquid hydrogen (LH2) is emerging as an alternative fuel for future aircraft. As a result, there is a need for hydrogen tank storage systems, for these aircraft applications, that are expected to provide sufficient capacity for flight durations ranging from a few minutes to several days. It is understood that the development of a large, lightweight, reusable cryogenic liquid storage tank is crucial to meet the goals of and supply power to hydrogen-fueled aircraft, especially for long flight durations. This report provides an annotated review (including the results of an extensive literature review) of the current state of the art of cryogenic tank materials, structural designs, and insulation systems along with the identification of key challenges with the intent of developing a lightweight and long-term storage system for LH2. The broad classes of insulation systems reviewed include foams (including advanced aerogels) and multilayer insulation (MLI) systems with vacuum. The MLI systems show promise for long-term applications. Structural configurations evaluated include single- and double-wall constructions, including sandwich construction. Potential wall material candidates are monolithic metals as well as polymer matrix composites and discontinuously reinforced metal matrix composites. For short-duration flight applications, simple tank designs may suffice. Alternatively, for longer duration flight applications, a double-wall construction with a vacuum-based insulation system appears to be the most optimum design. The current trends in liner material development are reviewed in the case that a liner is required to minimize or eliminate the loss of hydrogen fuel through permeation.

Mital, Subodh K.↗

Chemisorption and Diffusion of H on a Graphene Sheet and Single-Wall Carbon Nanotubes

Recent experiments on hydrogen storage in single wall nanotubes and nanotube bundles have reported large fractional weight of stored molecular hydrogen which are not in agreement with theoretical estimates based of simulation of hydrogen storage by physisorption mechanisms. Hydrogen storage in catalytically doped nanotube bundles indicate that atomic H might undergo chemisorption changing the basic nature of the storage mechanism under investigation by many groups. Using a generalized tight-binding molecular dynamics (GTBMD) method for reactive C-H dynamics, we investigate chemisorption and diffusion of atomic H on graphene sheet and C nanotubes. Effective potential energy surfaces (EPS) for chemisorption and diffusion are calculated for graphene sheet and nanotubes of different curvatures. Analysis of the activation barriers and quantum rate constants, computed via wave-packet dynamics method, will be discussed in this presentation.

Srivastava, Deepak↗

Flexible bulb large storage box hydrogen maser

The principal limitation on the accuracy of the hydrogen maser as a primary frequency standard has been the irreproducibility of the frequency shift caused by collisions of the radiating atoms with the walls of the vessel containing them. The flexible bulb-large storage box hydrogen maser allows correction for this wall shift within a single device, sidestepping the reproducibility problem, and reducing the frequency error from the wall shift to the level imposed by the device's stability. The principles of the device are discussed including the flexible bulb technique and the complications caused by a multiple region storage bulb. The stability of the device is discussed including a comparison with an ordinary hydrogen maser. Data is presented from a working flexible bulb-large storage box hydrogen maser demonstrating the feasibility of the device and showing some of its operating characteristics. The flexibility of the device is demonstrated by showing how the device's added degrees of freedom allow measurement of parameters unmeasurable in an ordinary hydrogen maser.

Reinhardt, V.↗

The storage of hydrogen in the form of metal hydrides: An application to thermal engines

The possibility of using LaNi56, FeTiH2, or MgH2 as metal hydride storage sytems for hydrogen fueled automobile engines is discussed. Magnesium copper and magnesium nickel hydrides studies indicate that they provide more stable storage systems than pure magnesium hydrides. Several test engines employing hydrogen fuel have been developed: a single cylinder motor originally designed for use with air gasoline mixture; a four-cylinder engine modified to run on an air hydrogen mixture; and a gas turbine.

Gales, C.↗

Hydrogen and Storage Initiatives at the NASA JSC White Sands Test Facility

NASA WSTF Hydrogen Activities: a) Aerospace Test; b) System Certification & Verification; c) Component, System, & Facility Hazard Assessment; d) Safety Training Technical Transfer: a) Development of Voluntary Consensus Standards and Practices; b) Support of National Hydrogen Infrastructure Development.

Maes, Miguel↗