Operational Testing of Densified Hydrogen Using G-M Refrigeration

Notardonato, William; Baik, J. H.; McIntosh, G. E.

doi:10.1063/1.1774668

Cited by 9 publications

(8 citation statements)

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“…Using free convection requires less active components than the forced convection methods and doesn't add heat from a pumping system. [13]. A commercial GiffordMcMahon cryocooler (Cryomech AL325) was integrated into a 150 liter LH2 dewar using a heat pipe to transfer refrigeration to copper cooling straps located in the liquid region.…”

Section: Ground Operations Demonstration Unit For Liquid Hydrogen (Gomentioning

confidence: 99%

Zero boil-off methods for large-scale liquid hydrogen tanks using integrated refrigeration and storage

Notardonato

Swanger

Fesmire

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Section: Ground Operations Demonstration Unit For Liquid Hydrogen (Gomentioning

confidence: 99%

Zero boil-off methods for large-scale liquid hydrogen tanks using integrated refrigeration and storage

Notardonato

Swanger

Fesmire

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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“…SpaceX introduces a different loading procedure for their rockets as it is loaded just 35 min before liftoff [60]. This fundamentally different sequence is required because of a densification process [61]. Due to the use of a cryogenic fluid, this loading process is comparable to aircraft refueling with LH2 because the same problems and solutions arise due to the low temperatures.…”

Section: Spacex Falcon 9 Loadingmentioning

confidence: 99%

Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

et al. 2022

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Green liquid hydrogen (LH2) could play an essential role as a zero-carbon aircraft fuel to reach long-term sustainable aviation. Excluding challenges such as electrolysis, transportation and use of renewable energy in setting up hydrogen (H2) fuel infrastructure, this paper investigates the interface between refueling systems and aircraft, and the impacts on fuel distribution at the airport. Furthermore, it provides an overview of key technology design decisions for LH2 refueling procedures and their effects on the turnaround times as well as on aircraft design. Based on a comparison to Jet A-1 refueling, new LH2 refueling procedures are described and evaluated. Process steps under consideration are connecting/disconnecting, purging, chill-down, and refueling. The actual refueling flow of LH2 is limited to a simplified Reynolds term of v·d=2.35 m2/s. A mass flow rate of 20 kg/s is reached with an inner hose diameter of 152.4 mm. The previous and subsequent processes (without refueling) require 9 min with purging and 6 min without purging. For the assessment of impacts on LH2 aircraft operation, process changes on the level of ground support equipment are compared to current procedures with Jet A-1. The technical challenges at the airport for refueling trucks as well as pipeline systems and dispensers are presented. In addition to the technological solutions, explosion protection as applicable safety regulations are analyzed, and the overall refueling process is validated. The thermodynamic properties of LH2 as a real, compressible fluid are considered to derive implications for airport-side infrastructure. The advantages and disadvantages of a subcooled liquid are evaluated, and cost impacts are elaborated. Behind the airport storage tank, LH2 must be cooled to at least 19K to prevent two-phase phenomena and a mass flow reduction during distribution. Implications on LH2 aircraft design are investigated by understanding the thermodynamic properties, including calculation methods for the aircraft tank volume, and problems such as cavitation and two-phase flows. In conclusion, the work presented shows that LH2 refueling procedure is feasible, compliant with the applicable explosion protection standards and hence does not impact the turnaround procedure. A turnaround time comparison shows that refueling with LH2 in most cases takes less time than with Jet A-1. The turnaround at the airport can be performed by a fuel truck or a pipeline dispenser system without generating direct losses, i.e., venting to the atmosphere.

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“…NASA continued development of densifier systems with the 2nd Generation Reusable Launch Vehicle program, funding three separate contracts to build prototype units and investigate refrigeration technologies [11]. Around this same time, NASA KSC and the Florida Solar Energy Center (FSEC) produced densified hydrogen on a small scale (180 liter) using an integrated Gifford-McMahon refrigerator and dewar [12]. This Integrated Refrigeration and Storage (IRAS) approach laid the groundwork for the large scale DH2 effort reported here.…”

Section: Introductionmentioning

confidence: 99%

Large scale production of densified hydrogen to the triple point and below

Swanger

Notardonato

Fesmire

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage technology at NASA Kennedy Space Center led to the production of large quantities of densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. Overall densification performance of the system is explored, and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing, and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. The phenomenon, observed at two fill levels, is detailed herein. The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed. IntroductionFluid-based fuels and/or oxidizers are routinely stored on-board vehicles of various types in order to provide chemical potential for an engine. In the vast majority of these applications the fluids are stored in a liquid state due to the significantly larger stored energy capacity compared to the gaseous phase, and can be kept at much lower pressures, avoiding the need for heavy pressure vessels. In either case, the key point is that the fluid acts as an energy carrier, therefore, the denser the fluid the greater the energy stored in a given volume. This is especially important in applications where the transportation of energy in fluid form is the express purpose, such as in ocean-going and roadable tankers. The term "densification" refers to the process of thermodynamically manipulating a fluid with the intent of increasing its density above that of a typical reference value, thereby increasing its energy storage potential. Reference values usually correspond to atmospheric conditions (temperature, pressure, or both), and in the case of cryogenic propellants such as liquid hydrogen (LH2), liquid methane or liquefied natural gas (LNG), and liquid oxygen (LOX), the reference density is that realized at the normal boiling point (NBP); i.e. when the fluid is completely saturated at atmospheric pressure.Historically, the maximum attainable cryofuel density has corresponded to the NBP storage condition. This constraint has been an important driver for the design of any application that utilizes cryogenic propellants, most notably chemical combustion-powered launch vehicles, by effectively dictating the required tank volumes. Therefore, increasing the density of the propellants can have a substantial effect on the overall vehicle design and/or performance. This is especially true for rockets

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Operational Testing of Densified Hydrogen Using G-M Refrigeration

Cited by 9 publications

References 0 publications

Zero boil-off methods for large-scale liquid hydrogen tanks using integrated refrigeration and storage

Zero boil-off methods for large-scale liquid hydrogen tanks using integrated refrigeration and storage

Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

Large scale production of densified hydrogen to the triple point and below

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