The Liquid Nitrogen System for Chamber A; A Change From Original Forced Flow Design to a Natural Flow (Thermo Siphon) System

Homan, Jonathan; Montz, Michael E.; Ganni, V.; Sidi‐Yekhlef, A.; Knudsen, P.; Creel, J.; Arenius, D.; Garcia, Sam; Weisend, J. G.

doi:10.1063/1.3422355

Cited by 3 publications

(3 citation statements)

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“…A previous paper [2] presented and compared the thermo-hydraulic process analysis of the original forced flow system to the proposed thermo-siphon design. The following simplified analysis, shown in Figure 1, provides a simpler analytical method to gain additional insight in the thermo-siphon system design, commissioning and operation.…”

Section: Simplified Thermodynamic Analysismentioning

confidence: 99%

“…Several options were proposed, and the thermo-siphon was clearly the best choice from a total cost and performance basis. The design and technical reasoning was detailed in a previously presented paper [2]. In summary, the thermo-siphon design reduced the number of valves and safety devices by more than 80%, reduced LN consumption, and did not require electrical power other than controls, which were easily put on an un-interruptible power supply (UPS).…”

Section: Introductionmentioning

confidence: 99%

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Commissioning of the liquid nitrogen thermo-siphon system for NASA-JSC Chamber-A

Homan¹,

Montz²,

Ganni³

et al. 2014

AIP Conference Proceedings

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Abstract. NASA's Space Environment Simulation Laboratory's (SESL) Chamber A, located at the Johnson Space Center in Houston Texas has recently implemented major enhancements of its cryogenic and vacuum systems. The new liquid nitrogen (LN) thermo-siphon system was successfully commissioned in August of 2012. Chamber A, which has 20 K helium cryo-panels (or "shrouds") which are shielded by 80 K nitrogen shrouds, is capable of simulating a deep space environment necessary to perform ground testing of NASA's James Webb Space Telescope (JWST). Chamber A's previous system used forced flow LN cooling with centrifugal pumps, requiring 220,000 liters of LN to cool-down and consuming 180,000 liters per day of LN in steady operation. The LN system did not have the reliability required to meet the long duration test of the JWST, and the cost estimate provided in the initial approach to NASA-JSC by the subcontractor for refurbishment of the system to meet the reliability goals was prohibitive. At NASA-JSC's request, the JLab Cryogenics Group provided alternative options in 2007, including a thermo-siphon, or natural flow system. This system, eliminated the need for pumps and used one tenth of the original control valves, relief valves, and burst disks. After the thermo-siphon approach was selected, JLab provided technical assistance in the process design, mechanical design, component specification development and commissioning oversight, while the installation and commissioning operations of the system was overseen by the Jacobs Technology/ESC group at JSC. The preliminary commissioning data indicate lower shroud temperatures, 68,000 liters to cool-down and less than 91,000 liters per day consumed in steady operation. All of the performance capabilities have exceeded the design goals. This paper will outline the comparison between the original system and the predicted results of the selected design option, and the commissioning results of thermo-siphon system.

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Section: Simplified Thermodynamic Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Commissioning of the liquid nitrogen thermo-siphon system for NASA-JSC Chamber-A

Homan¹,

Montz²,

Ganni³

et al. 2014

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

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“…It is well known that liquid nitrogen (LN2) is an easily available cryogen and is widely used by researchers and industries for various cryogenic experiments, such as LN2-cooled cryopumps [12,13] to attain ∼80 K easily. Even for 4 K operated systems, LN2-cooled thermal shields are used for large-size cryostats [14], tokamaks [15] and space simulation chambers [16] to control the radiation on the 4 K systems. Again, it has been observed in the literature [3,17] that the emissivity of a material changes significantly around LN2 temperature due to the changes in the surface properties of the material.…”

Section: Introductionmentioning

confidence: 99%

The development of a novel apparatus to measure the emissivity of high-roughness materials at 82 K

Dewasi,

Gangradey,

Mukherjee

et al. 2023

Meas. Sci. Technol.

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Emissivity of a material changes with temperature. The knowledge of emissivity plays an important role in the estimation of radiation heat load in cryogenic systems. As the values of emissivity of different materials at cryogenic temperature are scarcely available in literature, room temperature emissivity values are extensively used to estimate radiation heat load in a cryogenic system. This might lead to a significant deviation between the predicted and actual radiation properties at cryogenic temperature. Therefore, in the present work, an apparatus is developed based on calorimetric technique for measuring emissivity of an opaque material around 82 K. The novelties of the apparatus are compact size, ease of sample handling, lower time required to reach thermal equilibrium and most importantly, capacity to measure emissivity of a sample of high roughness. To understand the effectiveness of low and high emissivity coated heat radiators for the system, a theoretical as well as an experimental approach has been followed. It is found that the high emissive heat radiator led to a significant reduction in the time required to reach the thermal equilibrium as compared to a low-emissive heat radiator. To verify and validate this setup, emissivity of the Aeroglaze Z306 (high emissivity) and Cu (low emissivity) is measured and compared with the values reported in the literature. Finally, the work has been extended to measure emissivity at cryogenic temperature for the first time for PU1, SG121FD, and the indigenously developed novel materials such as black paints, adhesive and activated charcoals of different granule sizes.

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Creating the Deep Space Environment for Testing the James Webb Space Telescope at the Johnson Space Center’s Chamber A

Homan

Cerimele

Montz

2013

43rd International Conference on Environmental Systems

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Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft) in diameter and 36.6 m (120 ft) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960's to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and the modifications were funded, by the James Webb Space Telescope program, and this telescope which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber's new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to remove dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink and, the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in the overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

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The Liquid Nitrogen System for Chamber A; A Change From Original Forced Flow Design to a Natural Flow (Thermo Siphon) System

Cited by 3 publications

References 0 publications

Commissioning of the liquid nitrogen thermo-siphon system for NASA-JSC Chamber-A

Commissioning of the liquid nitrogen thermo-siphon system for NASA-JSC Chamber-A

The development of a novel apparatus to measure the emissivity of high-roughness materials at 82 K

Creating the Deep Space Environment for Testing the James Webb Space Telescope at the Johnson Space Center’s Chamber A

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