Helium compressors for closed-cycle, 4.5-Kelvin refrigerators

NASA Technical Reports Server (NTRS)

Hanson, T. R.

1992-01-01

An improved helium compressor for traveling-wave maser and closed-cycle refrigerator systems was developed and is currently being supplied to the DSN. This new 5-hp compressor package is designed to replace the current 3-hp DSN compressors. The new compressor package was designed to retrofit into the existing 3-hp compressor frame and reuse many of the same components, therefore saving the cost of documenting and fabricating these components when implementing a new 5-hp compressor.

Oxygen chemisorption compressor study for cryogenic J-T refrigeration

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Blue, Gary D.

1987-01-01

Over twenty potentially reversible heat-powered oxide reactions have been studied and/or tested to determine their potential use as thermochemical oxygen compressors for cryogenic J-T LO2 refrigerators. One gas-solid compound family, Pr(1-n)Ce(n)O(x), proved to be completely reversible with fast kinetics for all pressure ranges tested below 650 C. With a heat-powered charcoal/methane physical adsorption upper stage and a Pr(1-n)Ce(n)O(x) chemisorption lower stage, temperatures should be attainable in the 55-80 K range for less power and over five times less weight than for charcoal/nitrogen sorption refrigeration systems. Total system power requirements with a hydride chemisorption lower stage (10 K to 7 K minimum) are about three times less than any mechanical refrigerator, and spacecraft refrigeration weights are about twenty times less. Due to the lack of wear-related moving parts in sorption refrigerators, life expectancy is at least ten years, and there essentially no vibration.

Thermal conductance modeling and characterization of the SuperCDMS-SNOLAB sub-Kelvin cryogenic system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhuley, R. C.; Hollister, M. I.; Ruschman, M. K.

The detectors of the Super Cryogenic Dark Matter Search experiment at SNOLAB (SuperCDMS SNOLAB) will operate in a seven-layered cryostat with thermal stages between room temperature and the base temperature of 15 mK. The inner three layers of the cryostat, which are to be nominally maintained at 1 K, 250 mK, and 15 mK, will be cooled by a dilution refrigerator via conduction through long copper stems. Bolted and mechanically pressed contacts, at and cylindrical, as well as exible straps are the essential stem components that will facilitate assembly/dismantling of the cryostat. These will also allow for thermal contractions/movements duringmore » cooldown of the sub-Kelvin system. To ensure that these components and their contacts meet their design thermal conductance, prototypes were fabricated and cryogenically tested. The present paper gives an overview of the SuperCDMS SNOLAB sub-Kelvin architecture and its conductance requirements. Results from the conductance measurements tests and from sub-Kelvin thermal modeling are discussed.« less

The kelvin redefined

NASA Astrophysics Data System (ADS)

Machin, Graham

2018-02-01

On 20 May 2019 it is anticipated that the most radical revision of the International System of Units (the SI), since its inception, will come into force. From that point, all the SI units will be based on defined values of fundamental constants of nature. In this paper the redefinition of the kelvin and its implications are considered. The topic will be introduced by discussing how the wording of the new definition of the kelvin developed. The kelvin redefinition is reliant on a secure low-uncertainty value of the Boltzmann constant; its determination by different physical methods and how the final definitive value for the kelvin redefinition was arrived at is discussed. The redefined kelvin will be implemented through a document known as the mise en pratique (i.e. the ‘practical realisation’) for the definition of the kelvin (MeP-K). The development and contents of the MeP-K will be described. There follows a discussion of contemporary primary thermometry, which is the bedrock on which a secure kelvin redefinition will be founded. Finally the paper ends with a discussion of the implications of the redefinition, for traceability, and, more widely, the practice of thermometry in general.

The LiteBIRD Satellite Mission: Sub-Kelvin Instrument

NASA Astrophysics Data System (ADS)

Suzuki, A.; Ade, P. A. R.; Akiba, Y.; Alonso, D.; Arnold, K.; Aumont, J.; Baccigalupi, C.; Barron, D.; Basak, S.; Beckman, S.; Borrill, J.; Boulanger, F.; Bucher, M.; Calabrese, E.; Chinone, Y.; Cho, S.; Crill, B.; Cukierman, A.; Curtis, D. W.; de Haan, T.; Dobbs, M.; Dominjon, A.; Dotani, T.; Duband, L.; Ducout, A.; Dunkley, J.; Duval, J. M.; Elleflot, T.; Eriksen, H. K.; Errard, J.; Fischer, J.; Fujino, T.; Funaki, T.; Fuskeland, U.; Ganga, K.; Goeckner-Wald, N.; Grain, J.; Halverson, N. W.; Hamada, T.; Hasebe, T.; Hasegawa, M.; Hattori, K.; Hattori, M.; Hayes, L.; Hazumi, M.; Hidehira, N.; Hill, C. A.; Hilton, G.; Hubmayr, J.; Ichiki, K.; Iida, T.; Imada, H.; Inoue, M.; Inoue, Y.; Irwin, K. D.; Ishino, H.; Jeong, O.; Kanai, H.; Kaneko, D.; Kashima, S.; Katayama, N.; Kawasaki, T.; Kernasovskiy, S. A.; Keskitalo, R.; Kibayashi, A.; Kida, Y.; Kimura, K.; Kisner, T.; Kohri, K.; Komatsu, E.; Komatsu, K.; Kuo, C. L.; Kurinsky, N. A.; Kusaka, A.; Lazarian, A.; Lee, A. T.; Li, D.; Linder, E.; Maffei, B.; Mangilli, A.; Maki, M.; Matsumura, T.; Matsuura, S.; Meilhan, D.; Mima, S.; Minami, Y.; Mitsuda, K.; Montier, L.; Nagai, M.; Nagasaki, T.; Nagata, R.; Nakajima, M.; Nakamura, S.; Namikawa, T.; Naruse, M.; Nishino, H.; Nitta, T.; Noguchi, T.; Ogawa, H.; Oguri, S.; Okada, N.; Okamoto, A.; Okamura, T.; Otani, C.; Patanchon, G.; Pisano, G.; Rebeiz, G.; Remazeilles, M.; Richards, P. L.; Sakai, S.; Sakurai, Y.; Sato, Y.; Sato, N.; Sawada, M.; Segawa, Y.; Sekimoto, Y.; Seljak, U.; Sherwin, B. D.; Shimizu, T.; Shinozaki, K.; Stompor, R.; Sugai, H.; Sugita, H.; Suzuki, J.; Tajima, O.; Takada, S.; Takaku, R.; Takakura, S.; Takatori, S.; Tanabe, D.; Taylor, E.; Thompson, K. L.; Thorne, B.; Tomaru, T.; Tomida, T.; Tomita, N.; Tristram, M.; Tucker, C.; Turin, P.; Tsujimoto, M.; Uozumi, S.; Utsunomiya, S.; Uzawa, Y.; Vansyngel, F.; Wehus, I. K.; Westbrook, B.; Willer, M.; Whitehorn, N.; Yamada, Y.; Yamamoto, R.; Yamasaki, N.; Yamashita, T.; Yoshida, M.

2018-05-01

Inflation is the leading theory of the first instant of the universe. Inflation, which postulates that the universe underwent a period of rapid expansion an instant after its birth, provides convincing explanation for cosmological observations. Recent advancements in detector technology have opened opportunities to explore primordial gravitational waves generated by the inflation through "B-mode" (divergent-free) polarization pattern embedded in the cosmic microwave background anisotropies. If detected, these signals would provide strong evidence for inflation, point to the correct model for inflation, and open a window to physics at ultra-high energies. LiteBIRD is a satellite mission with a goal of detecting degree-and-larger-angular-scale B-mode polarization. LiteBIRD will observe at the second Lagrange point with a 400 mm diameter telescope and 2622 detectors. It will survey the entire sky with 15 frequency bands from 40 to 400 GHz to measure and subtract foregrounds. The US LiteBIRD team is proposing to deliver sub-Kelvin instruments that include detectors and readout electronics. A lenslet-coupled sinuous antenna array will cover low-frequency bands (40-235 GHz) with four frequency arrangements of trichroic pixels. An orthomode-transducer-coupled corrugated horn array will cover high-frequency bands (280-402 GHz) with three types of single frequency detectors. The detectors will be made with transition edge sensor (TES) bolometers cooled to a 100 milli-Kelvin base temperature by an adiabatic demagnetization refrigerator. The TES bolometers will be read out using digital frequency multiplexing with Superconducting QUantum Interference Device (SQUID) amplifiers. Up to 78 bolometers will be multiplexed with a single SQUID amplifier. We report on the sub-Kelvin instrument design and ongoing developments for the LiteBIRD mission.

Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

DOE PAGES

Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.; ...

2016-09-09

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo 2Zn 20, can be used for adiabatic demagnetization refrigeration, which does not requiremore » 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb 1$-$xSc xCo 2Zn 20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.« less

Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo 2Zn 20, can be used for adiabatic demagnetization refrigeration, which does not requiremore » 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb 1$-$xSc xCo 2Zn 20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.« less

PIPER Continuous Adiabatic Demagnetization Refrigerator

NASA Technical Reports Server (NTRS)

Kimball, Mark O.; Shirron, Peter J.; Canavan, Edgar R.; James, Bryan L.; Sampson, Michael A.; Letmate, Richard V.

2017-01-01

We report upon the development and testing of a 4-stage adiabatic demagnetization refrigerator (ADR) capable of continuous cooling at 0.100 Kelvin. This cooler is being built to cool the detector array aboard NASA's Primordial Inflation Polarization Explorer (PIPER) observatory. The goal of this balloon mission is to measure the primordial gravitational waves that should exist if the theory of cosmological inflation is correct. At altitude, the ADR will hold the array of transition-edge sensors at 100 mK continuously while periodically rejecting heat to a 1.2 K pumped helium bath. During testing on ground, the array is held at the same temperature but heat is rejected to a 4.2 K helium bath indicating the flexibility in this coolers design.

The Oxidation Products of Aluminum Hydride and Boron Aluminum Hydride Clusters

DTIC Science & Technology

2016-01-04

AFRL-AFOSR-VA-TR-2016-0075 The Oxidation Products of Aluminum Hydride and Boron Aluminum Hydride Clusters KIT BOWEN JOHNS HOPKINS UNIV BALTIMORE MD...Hydride and Boron Aluminum Hydride Clusters 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-14-1-0324 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) KIT...of both Aluminum Hydride Cluster Anions and Boron Aluminum Hydride Cluster Anions with Oxygen: Anionic Products The anionic products of reactions

Hydriding process

DOEpatents

Raymond, J.W.; Taketani, H.

1973-12-01

BS>A method is described for hydriding a body of a Group IV-B metal, preferably zirconium, to produce a crack-free metal-hydride bedy of high hydrogen content by cooling the body at the beta to beta + delta boundary, without further addition of hydrogen, to precipitate a fine-grained delta-phase metal hydride in the beta + delta phase region and then resuming the hydriding, preferably preceded by a reheating step. (Official Gazette)

A milliKelvin scanning Hall probe microscope for high resolution magnetic imaging

NASA Astrophysics Data System (ADS)

Khotkevych, V. V.; Bending, S. J.

2009-02-01

The design and performance of a novel scanning Hall probe microscope for milliKelvin magnetic imaging with submicron lateral resolution is presented. The microscope head is housed in the vacuum chamber of a commercial 3He-refrigerator and operates between room temperature and 300 mK in magnetic fields up to 10 T. Mapping of the local magnetic induction at the sample surface is performed by a micro-fabricated 2DEG Hall probe equipped with an integrated STM tip. The latter provides a reliable mechanism of surface tracking by sensing and controlling the tunnel currents. We discuss the results of tests of the system and illustrate its potential with images of suitable reference samples captured in different modes of operation.

Near-field refrigeration and tunable heat exchange through four-wave mixing

NASA Astrophysics Data System (ADS)

Khandekar, Chinmay; Messina, Riccardo; Rodriguez, Alejandro W.

2018-05-01

We modify and extend a recently proposed four-wave mixing scheme [C. Khandekar and A. Rodriguez, Opt. Express 25(19), 23164 (2017)] for achieving near-field thermal upconversion and energy transfer, to demonstrate efficient thermal refrigeration at low intensities ˜ 109W/m2 over a wide range of gap sizes (from tens to hundreds of nanometers) and operational temperatures (from tens to hundreds of Kelvins). We further exploit the scheme to achieve magnitude and directional tunability of near-field heat exchange between bodies held at different temperatures.

PREFACE: Kelvin and Ireland

NASA Astrophysics Data System (ADS)

Flood, Raymond; McCartney, Mark; Whitaker, Andrew

2009-07-01

Sir Joseph Larmor unveiling the Kelvin memorial in the Botanic Gardens, Belfast on a rainy day in 1913 Sir Joseph Larmor unveiling the Kelvin memorial in the Botanic Gardens, Belfast on a rainy day in 1913 © The Ulster Museum: Hogg collection William Thomson, later Lord Kelvin, was born in Belfast in 1824, and his family had lived near Ballynahinch in the north of Ireland, quite close to Belfast, from the seventeenth century. At the time of Kelvin's birth, James Thomson, his father, was Professor of Mathematics at the Belfast Royal Academical Institution (Inst). However, following the death of his wife in 1830, James took up a new position as Professor at the University of Glasgow, and he and his children moved there in 1832. Apart from three years studying at Cambridge, and a very brief period immediately afterwards travelling and teaching in Cambridge, Kelvin was to spend the rest of his life in Glasgow, where he occupied the Chair of Natural Philosophy (or Physics) for 53 years. The natural assumption might be that his birth in Ireland was irrelevant to Kelvin's life and work, and that the fine monument erected in his honour in Belfast's Botanic Gardens, which is pictured on the front cover of this volume, was more a demonstration of civic pride than a recognition of an aspect of Kelvin's life which was important to him. The purpose of the meeting was to demon strate that this was not the case, that, great Glaswegian as he undoubtedly became, Kelvin always delighted in the title of Irishman. The influence of his father, very much an Ulsterman, was immense, and Kelvin and his siblings were to follow his non-sectarian and reforming approach. Also important for Kelvin was his Christian upbringing, which began in Belfast, and his beliefs were to play a role of importance in his life and indeed in much of his most important work, in particular that on thermodynamics. Two of his siblings returned to Belfast and spent much of their lives there, and Kelvin was a

Hydride compositions

DOEpatents

Lee, Myung, W.

1994-01-01

Disclosed are a composition for use in storing hydrogen and a method for making the composition. The composition comprises a mixture of two or more hydrides, each hydride having a different series of hydrogen sorption isotherms that contribute to the overall isotherms of the mixture. The hydrides are chosen so that the isotherms of the mixture have regions wherein the H equilibrium pressure increases with increasing hydrogen, preferably linearly. The isotherms of the mixture can be adjusted by selecting hydrides with different isotherms and by varying the amounts of the individual hydrides, or both. Preferably, the mixture is made up of hydrides that have isotherms with substantially flat plateaus and in nearly equimolar amounts. The composition is activated by degassing, exposing to H, and then heating below the softening temperature of any of the constituents. When the composition is used to store hydrogen, its hydrogen content can be found simply by measuring P{sub H}{sub 2} and determining H/M from the isothermic function of the composition.

Hydride compositions

DOEpatents

Lee, Myung W.

1995-01-01

A composition for use in storing hydrogen, and a method for making the composition. The composition comprises a mixture of two or more hydrides, each hydride having a different series of hydrogen sorption isotherms that contribute to the overall isotherms of the mixture. The hydrides are chosen so that the isotherms of the mixture have regions wherein the hydrogen equilibrium pressure increases with increasing hydrogen, preferably linearly. The isotherms of the mixture can be adjusted by selecting hydrides with different isotherms and by varying the amounts of the individual hydrides, or both. Preferably, the mixture is made up of hydrides that have isotherms with substantially flat plateaus and in nearly equimolar amounts. The composition is activated by degassing, exposing to hydrogen and then heating at a temperature below the softening temperature of any of the. constituents so that their chemical and structural integrity is preserved. When the composition is used to store hydrogen, its hydrogen content can be found simply by measuring P.sub.H.sbsb.2 and determining H/M from the isothermic function of the composition.

Equatorial Kelvin waves: A UARS MLS view

NASA Technical Reports Server (NTRS)

Canziani, Pablo O.; Holton, James R.; Fishbein, Evan; Froidevaux, Lucien; Waters, Joe W.

1994-01-01

Data from the Microwave Limb Sounder (MLS) instrument on the Upper Atmosphere Research Satellite (UARS) are used to compare two periods of Kelvin wave activity during different stages of the equatorial quasi-biennial oscillation. The analysis is carried out using an asynoptic mapping technique. A wide bandpass filter is used to isolate the frequency bands where Kelvin waves have been identified in previous studies. Time-height and time-latitude plots of the bandpassed data are used to identify Kelvin wave activity in the temperature and ozone fields. Frequency spectra of temperature and ozone amplitudes are constructed to further analyze the latitudinal and meridional distribution of Kelvin wave activity in zonal wavenumbers 1 and 2. The characteristics identified in these plots agree well with theoretical predictions and previous observations of middle atmosphere Kelvin waves. The time-height and time-latitude plots support the existence of Kelvin waves in discrete frequency bands; the slow, fast, and ultrafast Kelvin modes are all identified in the data. The characteristics of these modes do not vary much despite different mean flow conditions in the two periods examined. For the Kelvin wave-induced perturbations in ozone, the change from a transport-dominated regime below 10 hPa to a photochemically controlled regime above 10 hPa is clearly apparent in the height dependence of the phase difference between temperature and ozone. The ratios of the ozone perturbation amplitude to the temperature perturbation amplitude for the various observed Kelvin wave modes are in agreement with model estimates and LIMS (Limb Infrared Monitor of the Stratosphere) observations in the lower half of the region sampled but appear to be too large in the upper stratosphere and lower mesosphere.

Lord Kelvin's atmospheric electricity measurements

NASA Astrophysics Data System (ADS)

Aplin, Karen; Harrison, R. Giles; Trainer, Matthew; Hough, James

2013-04-01

Lord Kelvin (William Thomson), one of the greatest Victorian scientists, made a substantial but little-recognised contribution to geophysics through his work on atmospheric electricity. He developed sensitive instrumentation for measuring the atmospheric electric field, including invention of a portable electrometer, which made mobile measurements possible for the first time. Kelvin's measurements of the atmospheric electric field in 1859, made during development of the portable electrometer, can be used to deduce the substantial levels of particulate pollution blown over the Scottish island of Arran from the industrial mainland. Kelvin was also testing the electrometer during the largest solar flare ever recorded, the "Carrington event" in the late summer of 1859. Subsequently, Lord Kelvin also developed a water dropper sensor, and employed photographic techniques for "incessant recording" of the atmospheric electric field, which led to the long series of measurements recorded at UK observatories for the remainder of the 19th and much of the 20th century. These data sets have been valuable in both studies of historical pollution and cosmic ray effects on atmospheric processes.

Predicting Hydride Donor Strength via Quantum Chemical Calculations of Hydride Transfer Activation Free Energy.

PubMed

Alherz, Abdulaziz; Lim, Chern-Hooi; Hynes, James T; Musgrave, Charles B

2018-01-25

We propose a method to approximate the kinetic properties of hydride donor species by relating the nucleophilicity (N) of a hydride to the activation free energy ΔG ⧧ of its corresponding hydride transfer reaction. N is a kinetic parameter related to the hydride transfer rate constant that quantifies a nucleophilic hydridic species' tendency to donate. Our method estimates N using quantum chemical calculations to compute ΔG ⧧ for hydride transfers from hydride donors to CO 2 in solution. A linear correlation for each class of hydrides is then established between experimentally determined N values and the computationally predicted ΔG ⧧ ; this relationship can then be used to predict nucleophilicity for different hydride donors within each class. This approach is employed to determine N for four different classes of hydride donors: two organic (carbon-based and benzimidazole-based) and two inorganic (boron and silicon) hydride classes. We argue that silicon and boron hydrides are driven by the formation of the more stable Si-O or B-O bond. In contrast, the carbon-based hydrides considered herein are driven by the stability acquired upon rearomatization, a feature making these species of particular interest, because they both exhibit catalytic behavior and can be recycled.

Design, Project Execution, and Commissioning of the 1.8 K Superfluid Helium Refrigeration System for SRF Cryomodule Testing

DOE PAGES

Treite, P.; Nuesslein, U.; Jia, Yi; ...

2015-07-15

The Fermilab Cryomodule Test Facility (CMTF) provides a test bed to measure the performance of superconducting radiofrequency (SRF) cryomodules (CM). These SRF components form the basic building blocks of future high intensity accelerators such as the International Linear Collider (ILC) and a Muon Collider. Linde Kryotechnik AG and Linde Cryogenics have designed, constructed and commissioned the superfluid helium refrigerator needed to support SRF component testing at the CMTF Facility. The hybrid refrigerator is designed to operate in a variety of modes and under a wide range of boundary conditions down to 1.8 Kelvin set by CM design. Special features ofmore » the refrigerator include the use of warm and cold compression and high efficiency turbo expanders.This paper gives an overview on the wide range of the challenging cooling requirements, the design, fabrication and the commissioning of the installed cryogenic system.« less

Suitability of commercially available laboratory cryogenic refrigerators to support shipboard electro-optical systems in the 10 - 77 Kelvin region

NASA Technical Reports Server (NTRS)

Hansen, R. G.; Byrd, E. A.

1983-01-01

The primary development of cryogenically cooled infrared systems was accomplished by FLIR systems designed for airborne, passive night vision. Essential to the development of these FLIR systems was a family of closed cycle refrigerators which had to meet a limited envelope requirement, utilize a nonlubricated compressor module, and be light in weight. Closed cycle refrigerators accomplished the same cooling function, they use modified oil lubricated reciprocating compressors which are limited in their axis of orientation to an angle of approximately 15-20 degrees maximum from horizon.

Heat Transfer Enhancement of Metal Hydride Particle Bed for Heat Driven Type Refrigerator by Carbon Fiber

NASA Astrophysics Data System (ADS)

Bae, Sang-Chul; Tanae, Takayuki; Monde, Masanori; Katsuta, Masafumi

A series of study has been performed on the metal hydride particle beds of Ti0.15Zr0.85Cr0.9Fe0.6Ni0.2Mn0.3Cu0.05 (MH-1, using for heat source), Ti0.73Zr0.27Cr1.2Fe0.3Ni0.1Mn0.4Cu0.05 (MH-2, using for cooling load) to measure the effective thermal conductivities. The effective thermal conductivities of activated and oxidized MH particle bed in helium have been examined. Experiment results show that pressure has great influence on effective thermal conductivity in low pressure range (<0.5 MPa). And that influence decreases rapidly with increase of gas pressure. The reason of pressure dependence at low pressure range is that the mean free path of gas becomes greater than effective thickness of gas film which is important to the heat transfer mechanism of particle bed. In order to enhance the poor thermal conductivity of metal hydride particle bed, carbon fiber mixing method has been used in this study. Three types, two insert methods and five mass percentages of carbon fiber have been examined and compared. The highest effective thermal conductivity of MH particle bed has been reached with Type B carbon fiber which has second higher thermal conductivity, and 2 weight percentage. This method has acquired 5-6 times higher thermal conductivity than pure metal hydride particle beds with quite low quantity of additives, only 2 mass% of carbon fiber. This is a good result comparing to other method which can reach higher effective thermal conductivity but needs much higher percentage of additives too.

Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

NASA Astrophysics Data System (ADS)

Palmer, A.; Silevitch, D. M.; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

2015-09-01

We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

Hydrogen, lithium, and lithium hydride production

DOEpatents

Brown, Sam W.; Spencer, Larry S.; Phillips, Michael R.; Powell, G. Louis; Campbell, Peggy J.

2017-06-20

A method is provided for extracting hydrogen from lithium hydride. The method includes (a) heating lithium hydride to form liquid-phase lithium hydride; (b) extracting hydrogen from the liquid-phase lithium hydride, leaving residual liquid-phase lithium metal; (c) hydriding the residual liquid-phase lithium metal to form refined lithium hydride; and repeating steps (a) and (b) on the refined lithium hydride.

Performance of solar refrigerant ejector refrigerating machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Khalidy, N.A.H.

1997-12-31

In this work a detailed analysis for the ideal, theoretical, and experimental performance of a solar refrigerant ejector refrigerating machine is presented. A comparison of five refrigerants to select a desirable one for the system is made. The theoretical analysis showed that refrigerant R-113 is more suitable for use in the system. The influence of the boiler, condenser, and evaporator temperatures on system performance is investigated experimentally in a refrigerant ejector refrigerating machine using R-113 as a working refrigerant.

Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, A; Silevitch, D M; Feng, Yejun

2015-09-01

We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, whilemore » at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.« less

Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in-situ tunability

DOE PAGES

Palmer, Alexander; Silevitch, Daniel; Feng, Yejun; ...

2015-09-04

We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with that of the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we then characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide rangemore » of pressure, while at the same time making possible precise steps across abrupt phase transitions such as that from insulator to metal.« less

Boron hydride polymer coated substrates

DOEpatents

Pearson, R.K.; Bystroff, R.I.; Miller, D.E.

1986-08-27

A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced into the chamber simultaneously with the generation of a plasma discharge within the chamber. A boron hydride plasma of ions, electrons and free radicals which is generated by the plasma discharge interacts to form a uniformly smooth boron hydride polymer which is deposited on the substrate.

Boron hydride polymer coated substrates

DOEpatents

Pearson, Richard K.; Bystroff, Roman I.; Miller, Dale E.

1987-01-01

A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced into the chamber simultaneously with the generation of a plasma discharge within the chamber. A boron hydride plasma of ions, electrons and free radicals which is generated by the plasma discharge interacts to form a uniformly smooth boron hydride polymer which is deposited on the substrate.

17. VIEW OF HYDRIDING SYSTEM IN BUILDING 881. THE HYDRIDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. VIEW OF HYDRIDING SYSTEM IN BUILDING 881. THE HYDRIDING SYSTEM WAS PART OF THE FAST ENRICHED URANIUM RECOVERY PROCESS. (11/11/59) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

A sub-Kelvin cryogen-free EPR system.

PubMed

Melhuish, Simon J; Stott, Chloe; Ariciu, Ana-Maria; Martinis, Lorenzo; McCulloch, Mark; Piccirillo, Lucio; Collison, David; Tuna, Floriana; Winpenny, Richard

2017-09-01

We present an EPR instrument built for operation at Q band below 1K. Our cryogen-free Dewar integrates with a commercial electro-magnet and bridge. A description of the cryogenic and RF systems is given, along with the adaptations to the standard EPR experiment for operation at sub-Kelvin temperatures. As a first experiment, the EPR spectra of powdered Cr 12 O 9 (OH) 3 [Formula: see text] were measured. The sub-Kelvin EPR spectra agree well with predictions, and the performance of the sub-Kelvin system at 5K is compared to that of a commercial spectrometer. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Adiabatic Demagnetisation Refrigerators for Future Sub-Millimetre Space Missions

NASA Astrophysics Data System (ADS)

Hepburn, I. D.; Davenport, I.; Smith, A.

1995-10-01

Space worthy refrigeration capable of providing a 100 mK and below heat load sink for bolometric detectors will be required for the next generation of sub-millimetre space missions. Adiabatic demagnetisation refrigeration (ADR), being a gravity independent laboratory method for obtaining such temperatures, is a favourable technique for utilisation in space. We show that by considering a 3 salt pill refrigerator rather than the classic single salt pill design the space prohibitive laboratory ADR properties of high magnetic field (6 Tesla) and a<2 K environment (provided by a bath of liquid4He) can be alleviated, while maintaining a sufficient low temperature hold time and short recycle time. The additional salt pills, composed of Gadolinium Gallium Garnet (GGG) provide intermediate cooling stages, enabling operation from a 4 K environment provided by a single 4 K mechanical cooler, thereby providing consumable free operation. Such ADRs could operate with fields as low as 1 Tesla allowing the use of high temperature, mechanically cooled superconducting magnets and so effectively remove the risk of quenching. We discuss the possibility of increasing the hold time from 3 hours, for the model presented, to between 40 and 80 hours, plus reducing the number of salt pills to two, through the use of a more efficient Garnet. We believe the technical advances necessitated by the envisaged ADRs are minimal and conclude that such ADRs offer a long orbital life time, consumable free, high efficiency means of milli-Kelvin cooling, requiring relatively little laboratory development.

Alternative refrigerants and refrigeration cycles for domestic refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sand, J.R.; Rice, C.L.; Vineyard, E.A.

1992-12-01

This project initially focused on using nonazeotropic refrigerant mixtures (NARMs) in a two-evaporator refrigerator-freezer design using two stages of liquid refrigerant subcooling. This concept was proposed and tested in 1975. The work suggested that the concept was 20% more efficient than the conventional one-evaporator refrigerator-freezer (RF) design. After considerable planning and system modeling based on using a NARM in a Lorenz-Meutzner (L-M) RF, the program scope was broadened to include investigation of a ``dual-loop`` concept where energy savings result from exploiting the less stringent operating conditions needed to satisfy cooling, of the fresh food section. A steady-state computer model (CYCLE-Z)more » capable of simulating conventional, dual loop, and L-M refrigeration cycles was developed. This model was used to rank the performance of 20 ozone-safe NARMs in the L-M refrigeration cycle while key system parameters were systematically varied. The results indicated that the steady-state efficiency of the L-M design was up to 25% greater than that of a conventional cycle. This model was also used to calculate the performance of other pure refrigerants relative to that of dichlorodifluoromethane, R-12, in conventional and dual-loop RF designs. Projected efficiency gains for these cycles were more modest, ranging from 0 to 10%. Individual compressor calorimeter tests of nine combinations of evaporator and condenser temperatures usually used to map RF compressor performance were carried out with R-12 and two candidate L-M NARMs in several compressors. Several models of a commercially produced two-evaporator RF were obtained as test units. Two dual-loop RF designs were built and tested as part of this project.« less

Fundamental experiments on hydride reorientation in zircaloy

NASA Astrophysics Data System (ADS)

Colas, Kimberly B.

In the current study, an in-situ X-ray diffraction technique using synchrotron radiation was used to follow directly the kinetics of hydride dissolution and precipitation during thermomechanical cycles. This technique was combined with conventional microscopy (optical, SEM and TEM) to gain an overall understanding of the process of hydride reorientation. Thus this part of the study emphasized the time-dependent nature of the process, studying large volume of hydrides in the material. In addition, a micro-diffraction technique was also used to study the spatial distribution of hydrides near stress concentrations. This part of the study emphasized the spatial variation of hydride characteristics such as strain and morphology. Hydrided samples in the shape of tensile dog-bones were used in the time-dependent part of the study. Compact tension specimens were used during the spatial dependence part of the study. The hydride elastic strains from peak shift and size and strain broadening were studied as a function of time for precipitating hydrides. The hydrides precipitate in a very compressed state of stress, as measured by the shift in lattice spacing. As precipitation proceeds the average shift decreases, indicating average stress is reduced, likely due to plastic deformation and morphology changes. When nucleation ends the hydrides follow the zirconium matrix thermal contraction. When stress is applied below the threshold stress for reorientation, hydrides first nucleate in a very compressed state similar to that of unstressed hydrides. After reducing the average strain similarly to unstressed hydrides, the average hydride strain reaches a constant value during cool-down to room temperature. This could be due to a greater ease of deforming the matrix due to the applied far-field strain which would compensate for the strains due to thermal contraction. Finally when hydrides reorient, the average hydride strains become tensile during the first precipitation regime and

Thermodynamic Hydricity of Transition Metal Hydrides

DOE PAGES

Wiedner, Eric S.; Chambers, Matthew B.; Pitman, Catherine L.; ...

2016-08-02

Transition metal hydrides play a critical role in stoichiometric and catalytic transformations. Knowledge of free energies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bondbreaking events that occur in a catalytic reaction. Thermodynamic hydricity is the free energy required to cleave an M-H bond to generate a hydride ion (H -). Three primary methods have been developed for hydricity determination: the hydride transfer method establishes hydride transfer equilibrium with a hydride donor/acceptor pair of known hydricity, the H 2 heterolysis method involves measuring the equilibrium of heterolytic cleavage of H 2more » in the presence of a base, and the potential-pK a method considers stepwise transfer of a proton and two electrons to give a net hydride transfer. Using these methods, over 100 thermodynamic hydricity values for transition metal hydrides have been determined in acetonitrile or water. In acetonitrile, the hydricity of metal hydrides spans a range of more than 50 kcal/mol. Finally, methods for using hydricity values to predict chemical reactivity are also discussed, including organic transformations, the reduction of CO 2, and the production and oxidation of hydrogen.« less

Low Global Warming Potential Refrigerants for Commercial Refrigeration Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, Brian A.; Sharma, Vishaldeep; Abdelaziz, Omar

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the highmore » refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Environmental concerns are driving regulations for the heating, ventilating, air-conditioning and refrigeration (HVAC&R) industry towards lower GWP alternatives to HFC refrigerants. Existing lower GWP refrigerant alternatives include hydrocarbons, such as propane (R-290) and isobutane (R-600a), as well as carbon dioxide (R-744), ammonia (R-717), and R-32. In addition, new lower GWP refrigerant alternatives are currently being developed by refrigerant manufacturers, including hydrofluoro-olefin (HFO) and unsaturated hydrochlorofluorocarbon (HCFO) refrigerants. The selection of an appropriate refrigerant for a given refrigeration application should be based on several factors, including the GWP of the refrigerant, the energy consumption of the refrigeration system over its operating lifetime, and leakage of refrigerant over the system lifetime. For example, focusing on energy efficiency alone may overlook the significant environmental impact of refrigerant leakage; while focusing on GWP alone might result in lower efficiency systems that result in higher indirect impact over the equipment lifetime. Thus, the objective of this Collaborative Research and Development Agreement (CRADA

Method for preparing porous metal hydride compacts

DOEpatents

Ron, Moshe; Gruen, Dieter M.; Mendelsohn, Marshall H.; Sheft, Irving

1981-01-01

A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

Method for preparing porous metal hydride compacts

DOEpatents

Ron, M.; Gruen, D.M.; Mendelsohn, M.H.; Sheft, I.

1980-01-21

A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

Applications of the Magnetocaloric Effect in Single-Stage, Multi-Stage and Continuous Adiabatic Demagnetization Refrigerators

NASA Technical Reports Server (NTRS)

Shirron, Peter J.

2014-01-01

Adiabatic demagnetization refrigerators (ADR), based on the magnetocaloric effect, are solid-state coolers that were the first to achieve cooling well into the sub-kelvin regime. Although supplanted by more powerful dilution refrigerators in the 1960s, ADRs have experienced a revival due to the needs of the space community for cooling astronomical instruments and detectors to temperatures below 100 mK. The earliest of these were single-stage refrigerators using superfluid helium as a heat sink. Their modest cooling power (<1 µW at 60 mK[1]) was sufficient for the small (6x6) detector arrays[2], but recent advances in arraying and multiplexing technologies[3] are generating a need for higher cooling power (5-10 µW), and lower temperature (<30 mK). Single-stage ADRs have both practical and fundamental limits to their operating range, as mass grows very rapidly as the operating range is expanded. This has led to the development of new architectures that introduce multi-staging as a way to improve operating range, efficiency and cooling power. Multi-staging also enables ADRs to be configured for continuous operation, which greatly improves cooling power per unit mass. This paper reviews the current field of adiabatic demagnetization refrigeration, beginning with a description of the magnetocaloric effect and its application in single-stage systems, and then describing the challenges and capabilities of multi-stage and continuous ADRs.

Refrigeration oils for low GWP refrigerants in various applications

NASA Astrophysics Data System (ADS)

Saito, R.; Sundaresan, S. G.

2017-08-01

The practical use of the refrigeration systems is considered as a methods to suppress global warming. The replacement of a refrigerant with a new one that has lower global warming potential (GWP) has been underway for several years. For the application fields of refrigerators, domestic air conditioners, automotive air conditioners and hot water dispensers, the investigation has almost finished. It is still underway for the application fields of commercial air conditioners and chillers, refrigeration facilities for cold storage, etc. And now, the refrigeration system is being applied in various ways to decrease global warming above the generation of electric power with organic Rankine cycle, the binary electric generation with ground source heat pump, and so on. In these situations, various refrigerants are developed and several kinds of suitable refrigeration oils are selected. This paper presents the consideration of suitable refrigeration oil for the various low GWP refrigerants.

Development of metal hydride composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congdon, J.W.

1992-12-01

Most of current hydride technology at Savannah River Site is based on beds of metal hydride powders; the expansion upon hydridation and the cycling results in continued breakdown into finer particles. Goal is to develop a composite which will contain the fines in a dimensionally stable matrix, for use in processes which require a stable gas flow through a hydride bed. Metal hydride composites would benefit the advanced Thermal Cycling Absorption process (hydrogen isotope separation), and the Replacement Tritium Facility (storage, pumping, compression, purification of hydrogen isotopes). These composites were fabricated by cold compaction of a mixture of metal hydridemore » granules and coarse copper powder; the porosity in the granules was introduced by means of ammonium carbonate. The composite pellets were cycled 138 times in hydrogen with the loss of LANA0.75 (LaNi{sub 4.25}Al{sub 0.75}) limited to the surface. Vacuum sintering can provide additional strength at the edges. Without a coating, the metal hydride particles exposed at the pellet surface can be removed by cycling several times in hydrogen.« less

Miscibility comparison for three refrigerant mixtures and four component refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, H.M.; Pate, M.B.

1999-07-01

Miscibility data were taken and compared for seven different refrigerants when mixed with the same polyol ester (POE) lubricant. Four of the seven refrigerants were single-component refrigerants while three of the refrigerants were mixtures composed of various combinations of the pure refrigerants. The purpose of this research was to investigate the difference in miscibility characteristics between refrigerant mixtures and their respective component refrigerants. The POE lubricant was a penta erythritol mixed-acid type POE which has a viscosity ISO32. The four pure refrigerants were R-32, R-125, R-134a, and R-143a and the three refrigerant mixtures were R-404A, R407C, and R-410A. The miscibilitymore » tests were performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The test cells were constructed to allow for complete visibility of the refrigerant/lubricant mixtures under all test conditions. The tests were performed over a concentration range of 0 to 100% and a temperature range of {minus}40 to 194 F. The miscibility test results for refrigerant mixtures are compared to component refrigerants. In all cases, the refrigerant mixtures appear to have better miscibility than their most immiscible pure component.« less

Rechargeable metal hydrides for spacecraft application

NASA Technical Reports Server (NTRS)

Perry, J. L.

1988-01-01

Storing hydrogen on board the Space Station presents both safety and logistics problems. Conventional storage using pressurized bottles requires large masses, pressures, and volumes to handle the hydrogen to be used in experiments in the U.S. Laboratory Module and residual hydrogen generated by the ECLSS. Rechargeable metal hydrides may be competitive with conventional storage techniques. The basic theory of hydride behavior is presented and the engineering properties of LaNi5 are discussed to gain a clear understanding of the potential of metal hydrides for handling spacecraft hydrogen resources. Applications to Space Station and the safety of metal hydrides are presented and compared to conventional hydride storage. This comparison indicates that metal hydrides may be safer and require lower pressures, less volume, and less mass to store an equivalent mass of hydrogen.

Refrigeration Playbook: Natural Refrigerants; Selecting and Designing Energy-Efficient Commercial Refrigeration Systems That Use Low Global Warming Potential Refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Caleb; Reis, Chuck; Nelson, Eric

This report provides guidance for selecting and designing energy efficient commercial refrigeration systems using low global warming potential refrigerants. Refrigeration systems are generally the largest energy end use in a supermarket type building, often accounting for more than half of a building's energy consumption.

Vanadium hydride deuterium-tritium generator

DOEpatents

Christensen, Leslie D.

1982-01-01

A pressure controlled vanadium hydride gas generator to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

Hydrogen /Hydride/-air secondary battery

NASA Technical Reports Server (NTRS)

Sarradin, J.; Bronoel, G.; Percheron-Guegan, A.; Achard, J. C.

1979-01-01

The use of metal hydrides as negative electrodes in a hydrogen-air secondary battery seems promising. However, in an unpressurized cell, more stable hydrides that LaNi5H6 must be selected. Partial substitutions of nickel by aluminium or manganese increase the stability of hydrides. Combined with an air reversible electrode, a specific energy close to 100 Wh/kg can be expected.

Physics of hydride fueled PWR

NASA Astrophysics Data System (ADS)

Ganda, Francesco

The first part of the work presents the neutronic results of a detailed and comprehensive study of the feasibility of using hydride fuel in pressurized water reactors (PWR). The primary hydride fuel examined is U-ZrH1.6 having 45w/o uranium: two acceptable design approaches were identified: (1) use of erbium as a burnable poison; (2) replacement of a fraction of the ZrH1.6 by thorium hydride along with addition of some IFBA. The replacement of 25 v/o of ZrH 1.6 by ThH2 along with use of IFBA was identified as the preferred design approach as it gives a slight cycle length gain whereas use of erbium burnable poison results in a cycle length penalty. The feasibility of a single recycling plutonium in PWR in the form of U-PuH2-ZrH1.6 has also been assessed. This fuel was found superior to MOX in terms of the TRU fractional transmutation---53% for U-PuH2-ZrH1.6 versus 29% for MOX---and proliferation resistance. A thorough investigation of physics characteristics of hydride fuels has been performed to understand the reasons of the trends in the reactivity coefficients. The second part of this work assessed the feasibility of multi-recycling plutonium in PWR using hydride fuel. It was found that the fertile-free hydride fuel PuH2-ZrH1.6, enables multi-recycling of Pu in PWR an unlimited number of times. This unique feature of hydride fuels is due to the incorporation of a significant fraction of the hydrogen moderator in the fuel, thereby mitigating the effect of spectrum hardening due to coolant voiding accidents. An equivalent oxide fuel PuO2-ZrO2 was investigated as well and found to enable up to 10 recycles. The feasibility of recycling Pu and all the TRU using hydride fuels were investigated as well. It was found that hydride fuels allow recycling of Pu+Np at least 6 times. If it was desired to recycle all the TRU in PWR using hydrides, the number of possible recycles is limited to 3; the limit is imposed by positive large void reactivity feedback.

Vanadium hydride deuterium-tritium generator

DOEpatents

Christensen, L.D.

1980-03-13

A pressure controlled vanadium hydride gas generator was designed to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

Hydrogen, lithium, and lithium hydride production

DOEpatents

Brown, Sam W; Spencer, Larry S; Phillips, Michael R; Powell, G. Louis; Campbell, Peggy J

2014-03-25

A method of producing high purity lithium metal is provided, where gaseous-phase lithium metal is extracted from lithium hydride and condensed to form solid high purity lithium metal. The high purity lithium metal may be hydrided to provide high purity lithium hydride.

Dimensionally stable metallic hydride composition

DOEpatents

Heung, Leung K.

1994-01-01

A stable, metallic hydride composition and a process for making such a composition. The composition comprises a uniformly blended mixture of a metal hydride, kieselguhr, and a ballast metal, all in the form of particles. The composition is made by subjecting a metal hydride to one or more hydrogen absorption/desorption cycles to disintegrate the hydride particles to less than approximately 100 microns in size. The particles are partly oxidized, then blended with the ballast metal and the kieselguhr to form a uniform mixture. The mixture is compressed into pellets and calcined. Preferably, the mixture includes approximately 10 vol. % or more kieselguhr and approximately 50 vol. % or more ballast. Metal hydrides that can be used in the composition include Zr, Ti, V, Nb, Pd, as well as binary, tertiary, and more complex alloys of La, Al, Cu, Ti, Co, Ni, Fe, Zr, Mg, Ca, Mn, and mixtures and other combinations thereof. Ballast metals include Al, Cu and Ni.

Baron Kelvin of Largs: an economical engineer.

PubMed

Fara, Patricia

2007-12-01

William Thomson--honoured as Baron Kelvin of Largs--was Victorian Britain's most famous physicist, especially celebrated for laying the trans-Atlantic telegraph cable. As well as profiting financially from his many engineering projects, Kelvin introduced influential theories about energy and electromagnetism, all strongly coloured by his industrial experiences and the thrifty attitudes of Scottish Christians. Never accepting radioactivity as an additional energy source to the sun, he insisted that the Earth's life span was far too short for evolution to have taken place.

Metal hydride composition and method of making

DOEpatents

Congdon, James W.

1995-01-01

A dimensionally stable hydride composition and a method for making such a composition. The composition is made by forming particles of a metal hydride into porous granules, mixing the granules with a matrix material, forming the mixture into pellets, and sintering the pellets in the absence of oxygen. The ratio of matrix material to hydride is preferably between approximately 2:1 and 4:1 by volume. The porous structure of the granules accommodates the expansion that occurs when the metal hydride particles absorb hydrogen. The porous matrix allows the flow of hydrogen therethrough to contact the hydride particles, yet supports the granules and contains the hydride fines that result from repeated absorption/desorption cycles.

Cyclopentadiene-mediated hydride transfer from rhodium complexes.

PubMed

Pitman, C L; Finster, O N L; Miller, A J M

2016-07-12

Attempts to generate a proposed rhodium hydride catalytic intermediate instead resulted in isolation of (Cp*H)Rh(bpy)Cl (1), a pentamethylcyclopentadiene complex, formed by C-H bond-forming reductive elimination from the fleeting rhodium hydride. The hydride transfer ability of diene 1 was explored through thermochemistry and hydride transfer reactions, including the reduction of NAD(+).

Kelvin wave-induced trace constituent oscillations in the equatorial stratosphere

NASA Technical Reports Server (NTRS)

Randel, William J.

1990-01-01

Kelvin wave induced oscillations in ozone (O3), water vapor (H2O), nitric acid (HNO3) and nitrogen dioxide (NO2) in the equatorial stratosphere are analyzed using Limb Infrared Monitor of the Stratosphere (LIMS) data. Power and cross-spectrum analyses reveal coherent eastward propagating zonal wave 1 and 2 constituent fluctuations, due to the influence of Kelvin waves previously documented in the LIMS data. Comparison is made between a preliminary and the archival versions of the LIMS data; significant differences are found, demonstrating the sensitivity of constituent retrievals to derived temperature profiles. Because Kelvin waves have vanishing meridional velocity, analysis of tracer transport in the meridional plane is substantially simplified. Kelvin wave vertical advection is demonstrated by coherent, in-phase temperature-tracer oscillations, co-located near regions of strong background vertical gradients.

Method of producing a chemical hydride

DOEpatents

Klingler, Kerry M.; Zollinger, William T.; Wilding, Bruce M.; Bingham, Dennis N.; Wendt, Kraig M.

2007-11-13

A method of producing a chemical hydride is described and which includes selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of a hydrocarbon; and reacting the composition with the source of the hydrocarbon to generate a chemical hydride.

Hydride heat pump

DOEpatents

Cottingham, James G.

1977-01-01

Method and apparatus for the use of hydrides to exhaust heat from one temperature source and deliver the thermal energy extracted for use at a higher temperature, thereby acting as a heat pump. For this purpose there are employed a pair of hydridable metal compounds having different characteristics working together in a closed pressure system employing a high temperature source to upgrade the heat supplied from a low temperature source.

Magnetic Refrigeration Development

NASA Technical Reports Server (NTRS)

Deardoff, D. D.; Johnson, D. L.

1984-01-01

Magnetic refrigeration is being developed to determine whether it may be used as an alternative to the Joule-Thomson circuit of a closed cycle refrigerator for providing 4 K refrigeration. An engineering model 4-15 K magnetic refrigerator has been designed and is being fabricated. This article describes the overall design of the magnetic refrigerator.

Metal hydride composition and method of making

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congdon, J.W.

1995-08-22

A dimensionally stable hydride composition and a method for making such a composition are disclosed. The composition is made by forming particles of a metal hydride into porous granules, mixing the granules with a matrix material, forming the mixture into pellets, and sintering the pellets in the absence of oxygen. The ratio of matrix material to hydride is preferably between approximately 2:1 and 4:1 by volume. The porous structure of the granules accommodates the expansion that occurs when the metal hydride particles absorb hydrogen. The porous matrix allows the flow of hydrogen there through to contact the hydride particles, yetmore » supports the granules and contains the hydride fines that result from repeated absorption/desorption cycles. 3 figs.« less

Liquid suspensions of reversible metal hydrides

DOEpatents

Reilly, J.J.; Grohse, E.W.; Winsche, W.E.

1983-12-08

The reversibility of the process M + x/2 H/sub 2/ ..-->.. MH/sub x/, where M is a metal hydride former that forms a hydride MH/sub x/ in the presence of H/sub 2/, generally used to store and recall H/sub 2/, is found to proceed under a liquid, thereby to reduce contamination, provide better temperature control and provide in situ mobility of the reactants. Thus, a slurry of particles of a metal hydride former with an inert solvent is subjected to temperature and pressure controlled atmosphere containing H/sub 2/, to store hydrogen (at high pressures) and to release (at low pressures) previously stored hydrogen. The direction of the flow of the H/sub 2/ through the liquid is dependent upon the H/sub 2/ pressure in the gas phase at a given temperature. When the former is above the equilibrium absorption pressure of the respective hydride the reaction proceeds to the right, i.e., the metal hydride is formed and hydrogen is stored in the solid particle. When the H/sub 2/ pressure in the gas phase is below the equilibrium dissociation pressure of the respective hydride the reaction proceeds to the left, the metal hydride is decomposed and hydrogen is released into the gas phase.

Sealed aerospace metal-hydride batteries

NASA Technical Reports Server (NTRS)

Coates, Dwaine

1992-01-01

Nickel metal hydride and silver metal hydride batteries are being developed for aerospace applications. There is a growing market for smaller, lower cost satellites which require higher energy density power sources than aerospace nickel-cadmium at a lower cost than space nickel-hydrogen. These include small LEO satellites, tactical military satellites and satellite constellation programs such as Iridium and Brilliant Pebbles. Small satellites typically do not have the spacecraft volume or the budget required for nickel-hydrogen batteries. NiCd's do not have adequate energy density as well as other problems such as overcharge capability and memory effort. Metal hydride batteries provide the ideal solution for these applications. Metal hydride batteries offer a number of advantages over other aerospace battery systems.

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1998-03-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to thermophysical properties, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air conditioning and refrigeration equipment. It also references documents addressing compatibility ofmore » refrigerants and lubricants with other materials.« less

The Kelvin-Thomson Atom. Part 2: The Many-Electron Atoms

ERIC Educational Resources Information Center

Walton, Alan J.

1977-01-01

Presents part two of a two-part article describing the Kelvin-Thomson atom. This part discusses the arrangement of electrons within the atom and examines some of the properties predicted for elements in the Kelvin-Thomson model. (SL)

The Occurrence of Tidal Hybrid Kelvin-Edge Waves in the Global Ocean

NASA Astrophysics Data System (ADS)

Kaur, H.; Buijsman, M. C.; Yankovsky, A. E.; Zhang, T.; Jeon, C. H.

2017-12-01

This study presents the analysis of hybrid Kelvin-edge waves on the continental shelves in a global ocean model. Our objective is to find areas where the transition occurs from Kelvin waves to hybrid Kelvin-edge waves. The change in continental shelf width may convert a Kelvin wave into a hybrid Kelvin-edge wave. In this process the group velocity reaches a minimum and tidal energy is radiated on and/or offshore [Zhang 2016]. We extract M2 SSH (Sea Surface Height) and velocity from the Hybrid Coordinate Ocean Model (HYCOM) and calculate barotropic energy fluxes. We analyze these three areas: the Bay of Biscay, the Amazon Shelf and North West Africa. In these three regions, the continental shelf widens in the propagation direction and the alongshore flux changes its direction towards the coast. A transect is taken at different points in these areas to compute the dispersion relations of the waves on the continental shelf. In model simulations, we change the bathymetry of the Bay of Biscay to study the behavior of the hybrid Kelvin-edge waves. BibliographyZhang, T., and A. E Yankovsky. (2016), On the nature of cross-isobath energy fluxes in topographically modified barotropic semidiurnal Kelvin waves, J. Geophys. Res. Oceans, 121, 3058-3074, doi:10.1002/2015JC011617.

Direct synthesis of catalyzed hydride compounds

DOEpatents

Gross, Karl J.; Majzoub, Eric

2004-09-21

A method is disclosed for directly preparing alkali metal aluminum hydrides such as NaAlH.sub.4 and Na.sub.3 AlH.sub.6 from either the alkali metal or its hydride, and aluminum. The hydride thus prepared is doped with a small portion of a transition metal catalyst compound, such as TiCl.sub.3, TiF.sub.3, or a mixture of these materials, in order to render them reversibly hydridable. The process provides for mechanically mixing the dry reagents under an inert atmosphere followed by charging the mixed materials with high pressure hydrogen while heating the mixture to about 125.degree. C. The method is relatively simple and inexpensive and provides reversible hydride compounds which are free of the usual contamination introduced by prior art wet chemical methods.

Estimation of the Kelvin wave contribution to the semiannual oscillation

NASA Technical Reports Server (NTRS)

Hitchman, Matthew H.; Leovy, Conway B.

1988-01-01

Daily temperature data acquired during the Limb Infrared Monitor of the Stratosphere experiment are used to study the behavior of Kelvin waves in the equatorial middle atmosphere. It is suggested that Kelvin wave packets of different zonal wave numbers propagate separately and may be forced separately. Two Kelvin wave regimes were identified during the October 1978 to May 1979 data period. Most of the properties of the observed waves are shown to be consistent with slowly-varying theory. Results suggest that gravity waves may contribute significantly to the equatorial stratopause semiannual oscillation.

Energy Efficient Commercial Refrigeration with Carbon Dioxide Refrigerant and Scroll Expanders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dieckmann, John

Current supermarket refrigeration systems are built around conventional fluorocarbon refrigerants – HFC-134a and the HFC blends R-507 and R404A, which replaced the CFC refrigerants, R-12 and R-502, respectively, used prior to the Montreal Protocol phase out of ozone depleting substances. While the HFC refrigerants are non-ozone depleting, they are strong greenhouse gases, so there has been continued interest in replacing them, particularly in applications with above average refrigerant leakage. Large supermarket refrigeration systems have proven to be particularly difficult to maintain in a leak-tight condition. Refrigerant charge losses of 15% of total charge per year are the norm, making themore » global warming impact of refrigerant emissions comparable to that associated with the energy consumption of these systems.« less

Thermoacoustic refrigeration

NASA Technical Reports Server (NTRS)

Garrett, Steven L.; Hofler, Thomas J.

1991-01-01

A new refrigerator which uses resonant high amplitude sound in inert gases to pump heat is described and demonstrated. The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part (the loudspeaker diaphragm). The thermoacoustic refrigerator has no sliding seals, requires no lubrication, uses only low-tolerance machine parts, and contains no expensive components. Because the compressor moving mass is typically small and the oscillation frequency is high, the small amount of vibration is very easily isolated. This low vibration and lack of sliding seals makes thermoacoustic refrigeration an excellent candidate for food refrigeration and commercial/residential air conditioning applications. The design, fabrication, and performance of the first practical, autonomous thermoacoustic refrigerator, which will be flown on the Space Shuttle (STS-42), are described, and designs for terrestrial applications are presented.

REACH. Refrigeration Units.

ERIC Educational Resources Information Center

Snow, Rufus; And Others

As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of refrigeration. The instructional units focus on refrigeration fundamentals, tubing and pipe, refrigerants, troubleshooting, window air conditioning, and…

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1996-07-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1996-11-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

Malone refrigeration

NASA Astrophysics Data System (ADS)

Swift, G. W.

Malone refrigeration is the use of a liquid near its critical points without evaporations as working fluid in a regenerative or recuperative refrigeration cycle such as the Stirling and Brayton cycles. It's potential advantages include compactness, efficiency, an environmentally benign working fluid, and reasonable cost. One Malone refrigerator has been built and studied; two more are under construction. Malone refrigeration is such a new, relatively unexplored technology that the potential for inventions leading to improvements in efficiency and simplicity is very high.

Metal hydride compositions and lithium ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Kwo; Nei, Jean

Heterogeneous metal hydride (MH) compositions comprising a main region comprising a first metal hydride and a secondary region comprising one or more additional components selected from the group consisting of second metal hydrides, metals, metal alloys and further metal compounds are suitable as anode materials for lithium ion cells. The first metal hydride is for example MgH.sub.2. Methods for preparing the composition include coating, mechanical grinding, sintering, heat treatment and quenching techniques.

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1997-02-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alterative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some maymore » be added at a later date. The database identifies sources of specific information on various refrigerants. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.« less

Metal Hydrides for High-Temperature Power Generation

DOE PAGES

Ronnebro, Ewa; Whyatt, Greg A.; Powell, Michael R.; ...

2015-08-10

Metal hydrides can be utilized for hydrogen storage and for thermal energy storage (TES) applications. By using TES with solar technologies, heat can be stored from sun energy to be used later which enables continuous power generation. We are developing a TES technology based on a dual-bed metal hydride system, which has a high-temperature (HT) metal hydride operating reversibly at 600-800°C to generate heat as well as a low-temperature (LT) hydride near room temperature that is used for hydrogen storage during sun hours until there is a need to produce electricity, such as during night time, a cloudy day, ormore » during peak hours. We proceeded from selecting a high-energy density, low-cost HT-hydride based on performance characterization on gram size samples, to scale-up to kilogram quantities and design, fabrication and testing of a 1.5kWh, 200kWh/m 3 bench-scale TES prototype based on a HT-bed of titanium hydride and a hydrogen gas storage instead of a LT-hydride. COMSOL Multiphysics was used to make performance predictions for cylindrical hydride beds with varying diameters and thermal conductivities. Based on experimental and modeling results, a bench-scale prototype was designed and fabricated and we successfully showed feasibility to meet or exceed all performance targets.« less

Hydridable material for the negative electrode in a nickel-metal hydride storage battery

DOEpatents

Knosp, Bernard; Bouet, Jacques; Jordy, Christian; Mimoun, Michel; Gicquel, Daniel

1997-01-01

A monophase hydridable material for the negative electrode of a nickel-metal hydride storage battery with a "Lave's phase" structure of hexagonal C14 type (MgZn.sub.2) has the general formula: Zr.sub.1-x Ti.sub.x Ni.sub.a Mn.sub.b Al.sub.c Co.sub.d V.sub.e where ##EQU1##

Reconnection properties in Kelvin-Helmholtz instabilities

NASA Astrophysics Data System (ADS)

Vernisse, Y.; Lavraud, B.; Eriksson, S.; Gershman, D. J.; Dorelli, J.; Pollock, C. J.; Giles, B. L.; Aunai, N.; Avanov, L. A.; Burch, J.; Chandler, M. O.; Coffey, V. N.; Dargent, J.; Ergun, R.; Farrugia, C. J.; Genot, V. N.; Graham, D.; Hasegawa, H.; Jacquey, C.; Kacem, I.; Khotyaintsev, Y. V.; Li, W.; Magnes, W.; Marchaudon, A.; Moore, T. E.; Paterson, W. R.; Penou, E.; Phan, T.; Retino, A.; Schwartz, S. J.; Saito, Y.; Sauvaud, J. A.; Schiff, C.; Torbert, R. B.; Wilder, F. D.; Yokota, S.

2017-12-01

Kelvin-Helmholtz instabilities are particular laboratories to study strong guide field reconnection processes. In particular, unlike the usual dayside magnetopause, the conditions across the magnetopause in KH vortices are quasi-symmetric, with low differences in beta and magnetic shear angle. We study these properties by means of statistical analysis of the high-resolution data of the Magnetospheric Multiscale mission. Several events of Kelvin-Helmholtz instabilities pas the terminator plane and a long lasting dayside instabilities event where used in order to produce this statistical analysis. Early results present a consistency between the data and the theory. In addition, the results emphasize the importance of the thickness of the magnetopause as a driver of magnetic reconnection in low magnetic shear events.

Metastable Metal Hydrides for Hydrogen Storage

DOE PAGES

Graetz, Jason

2012-01-01

The possibility of using hydrogen as a reliable energy carrier for both stationary and mobile applications has gained renewed interest in recent years due to improvements in high temperature fuel cells and a reduction in hydrogen production costs. However, a number of challenges remain and new media are needed that are capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides offer some hope of overcoming these challenges; however, many of the high capacity “reversible” hydrides exhibit a large endothermic decomposition enthalpy making it difficult to release the hydrogen at low temperatures. Onmore » the other hand, the metastable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favorable under ambient conditions. The rapid, low temperature hydrogen evolution rates that can be achieved with these materials offer much promise for mobile PEM fuel cell applications. However, a critical challenge exists to develop new methods to regenerate these hydrides directly from the reactants and hydrogen gas. This spotlight paper presents an overview of some of the metastable metal hydrides for hydrogen storage and a few new approaches being investigated to address the key challenges associated with these materials.« less

Refrigerant directly cooled capacitors

DOEpatents

Hsu, John S [Oak Ridge, TN; Seiber, Larry E [Oak Ridge, TN; Marlino, Laura D [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN

2007-09-11

The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

Reversible and irreversible heat engine and refrigerator cycles

NASA Astrophysics Data System (ADS)

Leff, Harvey S.

2018-05-01

Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

Multitip scanning bio-Kelvin probe

NASA Astrophysics Data System (ADS)

Baikie, I. D.; Smith, P. J. S.; Porterfield, D. M.; Estrup, P. J.

1999-03-01

We have developed a novel multitip scanning Kelvin probe which can measure changes in biological surface potential ΔVs to within 2 mV and, quasisimultaneously monitor displacement to <1 μm. The control and measurement subcomponents are PC based and incorporate a flexible user interface permitting software control of each individual tip, measurement, and scan parameters. We review the mode of operation and design features of the scanning bio-Kelvin probe including tip steering, signal processing, tip calibration, and novel tip tracking/dithering routines. This system uniquely offers both tip-to-sample spacing control (which is essential to avoid spurious changes in ΔVs due to variations in mean spacing) and a dithering routine to maintain tip orientation to the biological specimen, irrespective of the latter's movement. These features permit long term (>48 h) "active" tracking of the displacement and biopotentials developed along and around a plant shoot in response to an environmental stimulus, e.g., differential illumination (phototropism) or changes in orientation (gravitropism).

Iron hydrides formation in interstellar clouds

NASA Astrophysics Data System (ADS)

Bar-Nun, A.; Pasternak, M.; Barrett, P. H.

1980-07-01

A recent Moessbauer study with Fe-57 in a solid hydrogen or hydrogen-argon matrix demonstrated the formation of an iron hydride molecule (FeH2) at 2.5-5 K. Following this and other studies, the possible existence of iron hydride molecules in interstellar clouds is proposed. In clouds, the iron hydrides FeH and FeH2 would be formed only on grains, by encounters of H atoms or H2 molecules with Fe atoms which are adsorbed on the grains. The other transition metals, Sc, Ti, V, Cr, Mn, Co, N, Cd and also Cu and Ca form hydrides of the type M-H, which could be responsible, at least in part, for the depletion of these metals in clouds.

A validated non-linear Kelvin-Helmholtz benchmark for numerical hydrodynamics

NASA Astrophysics Data System (ADS)

Lecoanet, D.; McCourt, M.; Quataert, E.; Burns, K. J.; Vasil, G. M.; Oishi, J. S.; Brown, B. P.; Stone, J. M.; O'Leary, R. M.

2016-02-01

The non-linear evolution of the Kelvin-Helmholtz instability is a popular test for code verification. To date, most Kelvin-Helmholtz problems discussed in the literature are ill-posed: they do not converge to any single solution with increasing resolution. This precludes comparisons among different codes and severely limits the utility of the Kelvin-Helmholtz instability as a test problem. The lack of a reference solution has led various authors to assert the accuracy of their simulations based on ad hoc proxies, e.g. the existence of small-scale structures. This paper proposes well-posed two-dimensional Kelvin-Helmholtz problems with smooth initial conditions and explicit diffusion. We show that in many cases numerical errors/noise can seed spurious small-scale structure in Kelvin-Helmholtz problems. We demonstrate convergence to a reference solution using both ATHENA, a Godunov code, and DEDALUS, a pseudo-spectral code. Problems with constant initial density throughout the domain are relatively straightforward for both codes. However, problems with an initial density jump (which are the norm in astrophysical systems) exhibit rich behaviour and are more computationally challenging. In the latter case, ATHENA simulations are prone to an instability of the inner rolled-up vortex; this instability is seeded by grid-scale errors introduced by the algorithm, and disappears as resolution increases. Both ATHENA and DEDALUS exhibit late-time chaos. Inviscid simulations are riddled with extremely vigorous secondary instabilities which induce more mixing than simulations with explicit diffusion. Our results highlight the importance of running well-posed test problems with demonstrated convergence to a reference solution. To facilitate future comparisons, we include as supplementary material the resolved, converged solutions to the Kelvin-Helmholtz problems in this paper in machine-readable form.

A study of advanced magnesium-based hydride and development of a metal hydride thermal battery system

NASA Astrophysics Data System (ADS)

Zhou, Chengshang

Metal hydrides are a group of important materials known as energy carriers for renewable energy and thermal energy storage. A concept of thermal battery based on advanced metal hydrides is studied for heating and cooling of cabins in electric vehicles. The system utilizes a pair of thermodynamically matched metal hydrides as energy storage media. The hot hydride that is identified and developed is catalyzed MgH2 due to its high energy density and enhanced kinetics. TiV0.62Mn1.5, TiMn2, and LaNi5 alloys are selected as the matching cold hydride. A systematic experimental survey is carried out in this study to compare a wide range of additives including transitions metals, transition metal oxides, hydrides, intermetallic compounds, and carbon materials, with respect to their effects on dehydrogenation properties of MgH2. The results show that additives such as Ti and V-based metals, hydride, and certain intermetallic compounds have strong catalytic effects. Solid solution alloys of magnesium are exploited as a way to destabilize magnesium hydride thermodynamically. Various elements are alloyed with magnesium to form solid solutions, including indium and aluminum. Thermodynamic properties of the reactions between the magnesium solid solution alloys and hydrogen are investigated, showing that all the solid solution alloys that are investigated in this work have higher equilibrium hydrogen pressures than that of pure magnesium. Cyclic stability of catalyzed MgH2 is characterized and analyzed using a PCT Sievert-type apparatus. Three systems, including MgH2-TiH 2, MgH2-TiMn2, and MgH2-VTiCr, are examined. The hydrogenating and dehydrogenating kinetics at 300°C are stable after 100 cycles. However, the low temperature (25°C to 150°C) hydrogenation kinetics suffer a severe degradation during hydrogen cycling. Further experiments confirm that the low temperature kinetic degradation can be mainly related the extended hydrogenation-dehydrogenation reactions. Proof

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study.

PubMed

Haidari, Leila A; Brown, Shawn T; Wedlock, Patrick; Connor, Diana L; Spiker, Marie; Lee, Bruce Y

2017-04-19

Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as "electric refrigerators") at different locations in the supply chain under various circumstances. At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar refrigerator prices. Copyright © 2017. Published

Portable refrigerant charge meter and method for determining the actual refrigerant charge in HVAC systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhiming; Abdelaziz, Omar; LaClair, Tim L.

A refrigerant charge meter and a method for determining the actual refrigerant charge in HVAC systems are described. The meter includes means for determining an optimum refrigerant charge from system subcooling and system component parameters. The meter also includes means for determining the ratio of the actual refrigerant charge to the optimum refrigerant charge. Finally, the meter includes means for determining the actual refrigerant charge from the optimum refrigerant charge and the ratio of the actual refrigerant charge to the optimum refrigerant charge.

Mechanistic insights into iron catalyzed dehydrogenation of formic acid: β-hydride elimination vs. direct hydride transfer.

PubMed

Yang, Xinzheng

2013-09-07

Density functional theory calculations reveal a complete reaction mechanism with detailed energy profiles and transition state structures for the dehydrogenation of formic acid catalyzed by an iron complex, [P(CH2CH2PPh2)3FeH](+). In the cationic reaction pathway, a β-hydride elimination process is confirmed to be the rate-determining step in this catalytic reaction. A potential reaction pathway starting with a direct hydride transfer from HCOO(-) to Fe is found to be possible, but slightly less favorable than the catalytic cycle with a β-hydride elimination step.

Study on the Materials for Compressor and Reliability of Refrigeration Circuit in Refrigerator with R134a Refrigerant

NASA Astrophysics Data System (ADS)

Komatsubara, Takeo; Sunaga, Takasi; Takahasi, Yasuki

R134a was selected as the alternative refrigerant for R12 because of the similar thermodynamic properties with R12. But refrigeration oil for R12 couldn't be used for R134a because of the immiscibility with R134a. To solve this problem we researched miscible oil with R134a and selected polyol ester oil (POE) as refrigeration oil. But we found sludge deposition into capillary tube after life test of refrigerator with POE and detected metal soap, decomposed oil and alkaline ions by analysis of sludge. This results was proof of phenomena like oil degradation, precipitation of process materials and wear of compressor. Therefore we improved stability and lubricity of POE, reevaluated process materials and contaminations in refrigerating circuit. In this paper we discuss newly developed these technologies and evaluation results of it by life test of refrigerator.

Phase locking of convectively coupled equatorial atmospheric Kelvin waves over Indian Ocean basin

NASA Astrophysics Data System (ADS)

Baranowski, Dariusz; Flatau, Maria; Flatau, Piotr; Matthews, Adrian

2015-04-01

The properties of convectively coupled Kelvin waves in the Indian Ocean and their propagation over the Maritime Continent are studied. It is shown that Kelvin waves are longitude - diurnal cycle phase locked over the Maritime Continent, Africa and the Indian Ocean. Thus, it is shown that they tend to propagate over definite areas during specific times of the day. Over the Maritime Continent, longitude-diurnal cycle phase locking is such that it agrees with mean, local diurnal cycle of convection. The strength of the longitude-diurnal cycle phase locking differs between 'non-blocked' Kelvin waves, which make successful transition over the Maritime Continent, and 'blocked' waves that terminated within it. It is shown that a specific combination of Kelvin wave phase speed and time of the day at which a wave approaches the Maritime Continent influence the chance of successful transition into the Western Pacific. Kelvin waves that maintain phase speed of 10 to 11 degrees per day over the central-eastern Indian Ocean and arrive at 90E between 9UTC and 18UTC have the highest chance of being 'non-blocked' by the Maritime Continent. The distance between the islands of Sumatra and Borneo agrees with the distance travelled by an average convectively coupled Kelvin wave in one day. This suggests that the Maritime Continent may act as a 'filter' for Kelvin waves favoring successful propagation of those waves for which propagation is in phase with the local diurnal cycle of precipitation. The AmPm index, a simple measure of local diurnal cycle for propagating disturbances, is introduced and shown to be useful metric depicting key characteristics of the convection associated with propagating Kelvin waves.

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study☆

PubMed Central

Haidari, Leila A.; Brown, Shawn T.; Wedlock, Patrick; Connor, Diana L.; Spiker, Marie; Lee, Bruce Y.

2017-01-01

Background Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Methods Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as “electric refrigerators”) at different locations in the supply chain under various circumstances. Results At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Conclusion Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar

Functional Dependence of Thermodynamic and Thermokinetic Parameters of Refrigerants Used in Mine Air Refrigerators. Part 1 - Refrigerant R407C

NASA Astrophysics Data System (ADS)

Nowak, Bernard; Życzkowski, Piotr; Łuczak, Rafał

2017-03-01

The authors of this article dealt with the issue of modeling the thermodynamic and thermokinetic properties (parameters) of refrigerants. The knowledge of these parameters is essential to design refrigeration equipment, to perform their energy efficiency analysis, or to compare the efficiency of air refrigerators using different refrigerants. One of the refrigerants used in mine air compression refrigerators is R407C. For this refrigerant, 23 dependencies were developed, determining its thermodynamic and thermokinetic parameters in the states of saturated liquid, dry saturated vapour, superheated vapor, subcooled liquid, and in the two-phase region. The created formulas have been presented in Tables 2, 5, 8, 10 and 12, respectively. It should be noted that the scope of application of these formulas is wider than the range of changes of that refrigerant during the normal operation of mine refrigeration equipment. The article ends with the statistical verification of the developed dependencies. For this purpose, for each model correlation coefficients and coefficients of determination were calculated, as well as absolute and relative deviations between the given values from the program REFPROP 7 (Lemmon et al., 2002) and the calculated ones. The results of these calculations have been contained in Tables 14 and 15.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, Arnold R.

1987-01-01

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, Arnold R.

1987-01-01

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing he evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, A.R.

1987-06-23

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, A.R.

1987-11-24

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

Review of magnetic refrigeration system as alternative to conventional refrigeration system

NASA Astrophysics Data System (ADS)

Mezaal, N. A.; Osintsev, K. V.; Zhirgalova, T. B.

2017-10-01

The refrigeration system is one of the most important systems in industry. Developers are constantly seeking for how to avoid the damage to the environment. Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials, MCE warms as the magnetic moments of the atom are aligned by the application of a magnetic field. There are two types of magnetic phase changes that may occur at the Curie point: first order magnetic transition (FOMT) and second order magnetic transition (SOMT). The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative cycle), where the magnetic material matrix works both as a refrigerating medium and as a heat regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating fashion through the regenerator made of magnetocaloric material that is alternately magnetized and demagnetized. Many magnetic refrigeration prototypes with different designs and software models have been built in different parts of the world. In this paper, the authors try to shed light on the magnetic refrigeration and show its effectiveness compared with conventional refrigeration methods.

Discussion of Refrigeration Cycle Using Carbon Dioxide as Refrigerant

NASA Astrophysics Data System (ADS)

Ji, Amin; Sun, Miming; Li, Jie; Yin, Gang; Cheng, Keyong; Zhen, Bing; Sun, Ying

Nowadays, the problem of the environment goes worse, it urges people to research and study new energy-saving and environment-friendly refrigerants, such as carbon dioxide, at present, people do research on carbon dioxide at home and abroad. This paper introduces the property of carbon dioxide as a refrigerant, sums up and analyses carbon dioxide refrigeration cycles, and points out the development and research direction in the future.

Sodium-based hydrides for thermal energy applications

NASA Astrophysics Data System (ADS)

Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

2016-04-01

Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

A classical but new kinetic equation for hydride transfer reactions.

PubMed

Zhu, Xiao-Qing; Deng, Fei-Huang; Yang, Jin-Dong; Li, Xiu-Tao; Chen, Qiang; Lei, Nan-Ping; Meng, Fan-Kun; Zhao, Xiao-Peng; Han, Su-Hui; Hao, Er-Jun; Mu, Yuan-Yuan

2013-09-28

A classical but new kinetic equation to estimate activation energies of various hydride transfer reactions was developed according to transition state theory using the Morse-type free energy curves of hydride donors to release a hydride anion and hydride acceptors to capture a hydride anion and by which the activation energies of 187 typical hydride self-exchange reactions and more than thirty thousand hydride cross transfer reactions in acetonitrile were safely estimated in this work. Since the development of the kinetic equation is only on the basis of the related chemical bond changes of the hydride transfer reactants, the kinetic equation should be also suitable for proton transfer reactions, hydrogen atom transfer reactions and all the other chemical reactions involved with breaking and formation of chemical bonds. One of the most important contributions of this work is to have achieved the perfect unity of the kinetic equation and thermodynamic equation for hydride transfer reactions.

Inhibited solid propellant composition containing beryllium hydride

NASA Technical Reports Server (NTRS)

Thompson, W. W. (Inventor)

1978-01-01

An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene.

49 CFR 173.311 - Metal hydride storage systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Metal hydride storage systems. 173.311 Section 173... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.311 Metal hydride storage systems. The following packing instruction is applicable to transportable UN Metal hydride storage systems...

49 CFR 173.311 - Metal hydride storage systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Metal hydride storage systems. 173.311 Section 173... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.311 Metal hydride storage systems. The following packing instruction is applicable to transportable UN Metal hydride storage systems...

49 CFR 173.311 - Metal hydride storage systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Metal hydride storage systems. 173.311 Section 173... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.311 Metal hydride storage systems. The following packing instruction is applicable to transportable UN Metal hydride storage systems...

Thermoelectric refrigerator

NASA Technical Reports Server (NTRS)

Park, Brian V. (Inventor); Smith, Jr., Malcolm C. (Inventor); McGrath, Ralph D. (Inventor); Gilley, Michael D. (Inventor); Criscuolo, Lance (Inventor); Nelson, John L. (Inventor)

1996-01-01

A refrigerator is provided which combines the benefits of superinsulation materials with thermoelectric devices and phase change materials to provide an environmentally benign system that is energy efficient and can maintain relatively uniform temperatures for extended periods of time with relatively low electrical power requirements. The refrigerator includes a thermoelectric assembly having a thermoelectric device with a hot sink and a cold sink. The superinsulation materials include a plurality of vacuum panels. The refrigerator is formed from an enclosed structure having a door. The vacuum panels may be contained within the walls of the enclosed structure and the door. By mounting the thermoelectric assembly on the door, the manufacturer of the enclosed structure is simplified and the overall R rating of the refrigerator increased. Also an electrical motor and propellers may be mounted on the door to assist in the circulation of air to improve the efficiency of the cold sink and the hot sink. A propeller and/or impeller is preferably mounted within the refrigerator to assist in establishing the desired air circulation flow path.

A study of hydriding kinetics of metal hydrides using a physically based model

NASA Astrophysics Data System (ADS)

Voskuilen, Tyler G.

The reaction of hydrogen with metals to form metal hydrides has numerous potential energy storage and management applications. The metal hydrogen system has a high volumetric energy density and is often reversible with a high cycle life. The stored hydrogen can be used to produce energy through combustion, reaction in a fuel cell, or electrochemically in metal hydride batteries. The high enthalpy of the metal-hydrogen reaction can also be used for rapid heat removal or delivery. However, improving the often poor gravimetric performance of such systems through the use of lightweight metals usually comes at the cost of reduced reaction rates or the requirement of pressure and temperature conditions far from the desired operating conditions. In this work, a 700 bar Sievert system was developed at the Purdue Hydrogen Systems Laboratory to study the kinetic and thermodynamic behavior of high pressure hydrogen absorption under near-ambient temperatures. This system was used to determine the kinetic and thermodynamic properties of TiCrMn, an intermetallic metal hydride of interest due to its ambient temperature performance for vehicular applications. A commonly studied intermetallic hydride, LaNi5, was also characterized as a base case for the phase field model. The analysis of the data obtained from such a system necessitate the use of specialized techniques to decouple the measured reaction rates from experimental conditions. These techniques were also developed as a part of this work. Finally, a phase field model of metal hydride formation in mass-transport limited interstitial solute reactions based on the regular solution model was developed and compared with measured kinetics of LaNi5 and TiCrMn. This model aided in the identification of key reaction features and was used to verify the proposed technique for the analysis of gas-solid reaction rates determined volumetrically. Additionally, the phase field model provided detailed quantitative predictions of the

Structural Characterization of Metal Hydrides for Energy Applications

NASA Astrophysics Data System (ADS)

George, Lyci

Hydrogen can be an unlimited source of clean energy for future because of its very high energy density compared to the conventional fuels like gasoline. An efficient and safer way of storing hydrogen is in metals and alloys as hydrides. Light metal hydrides, alanates and borohydrides have very good hydrogen storage capacity, but high operation temperatures hinder their application. Improvement of thermodynamic properties of these hydrides is important for their commercial use as a source of energy. Application of pressure on materials can have influence on their properties favoring hydrogen storage. Hydrogen desorption in many complex hydrides occurs above the transition temperature. Therefore, it is important to study the physical properties of the hydride compounds at ambient and high pressure and/or high temperature conditions, which can assist in the design of suitable storage materials with desired thermodynamic properties. The high pressure-temperature phase diagram, thermal expansion and compressibility have only been evaluated for a limited number of hydrides so far. This situation serves as a main motivation for studying such properties of a number of technologically important hydrides. Focus of this dissertation was on X-ray diffraction and Raman spectroscopy studies of Mg2FeH6, Ca(BH4) 2, Mg(BH4)2, NaBH4, NaAlH4, LiAlH4, LiNH2BH3 and mixture of MgH 2 with AlH3 or Si, at different conditions of pressure and temperature, to obtain their bulk modulus and thermal expansion coefficient. These data are potential source of information regarding inter-atomic forces and also serve as a basis for developing theoretical models. Some high pressure phases were identified for the complex hydrides in this study which may have better hydrogen storage properties than the ambient phase. The results showed that the highly compressible B-H or Al-H bonds and the associated bond disordering under pressure is responsible for phase transitions observed in brorohydrides or

Concepts for a low-vibration and cryogen-free tabletop dilution refrigerator

NASA Astrophysics Data System (ADS)

Uhlig, Kurt

2017-10-01

The purpose of this article is to describe several concepts of how to cool a modern tabletop dilution refrigerator (DR) with a cryogen-free pulse tube cryocooler (PTC). Tabletop DRs have come more and more into the focus of scientists, recently, because they offer easy access to the mixing chamber mounting plate from all directions and because of their very short cooldown times. However, these milli-Kelvin coolers are precooled with LHe which makes their handling inconvenient and often expensive. In the paper it is explained how a cryocooler can be directly coupled to a DR unit making the use of LHe superfluous. Furthermore, concepts are discussed where a tabletop DR is cooled by a remote PTC; PTC and DR are mounted in separate vacuum containers which are connected by a stainless steel bellows tube. This kind of apparatus would offer an extremely low level of vibration at the mixing chamber mounting plate.

Laser refrigeration, alignment and rotation of levitated Yb3+:YLF nanocrystals

NASA Astrophysics Data System (ADS)

Rahman, A. T. M. Anishur; Barker, P. F.

2017-10-01

The ability to cool and manipulate levitated nanoparticles in vacuum is a promising tool for exploring macroscopic quantum mechanics1,2, precision measurements of forces3 and non-equilibrium thermodynamics4,5. The extreme isolation afforded by optical levitation offers a low-noise, undamped environment that has been used to measure zeptonewton forces3 and radiation pressure shot noise6, and to demonstrate centre-of-mass motion cooling7,8. Ground-state cooling and the creation of macroscopic quantum superpositions are now within reach, but control of both the centre of mass and internal temperature is required. While cooling the centre-of-mass motion to micro-kelvin temperatures has now been achieved, the internal temperature has remained at or above room temperature. Here, we realize a nanocryostat by refrigerating levitated Yb3+:YLF nanocrystals to 130 K using anti-Stokes fluorescence cooling, while simultaneously using the optical trapping field to align the crystal to maximize cooling.

Vaccine refrigeration

PubMed Central

McColloster, Patrick J; Martin-de-Nicolas, Andres

2014-01-01

This commentary reviews recent changes in Centers for Disease Control (CDC) vaccine storage guidelines that were developed in response to an investigative report by the Office of the Inspector General. The use of temperature data loggers with probes residing in glycol vials is advised along with storing vaccines in pharmaceutical refrigerators. These refrigerators provide good thermal distribution but can warm to 8 °C in less than one hour after the power is discontinued. Consequently, electric grid instability influences appropriate refrigerator selection and the need for power back-up. System Average Interruption Duration Index (SAIDI) values quantify this instability and can be used to formulate region-specific guidelines. A novel aftermarket refrigerator regulator with a battery back-up power supply and microprocessor control system is also described. PMID:24442209

Activated aluminum hydride hydrogen storage compositions and uses thereof

DOEpatents

Sandrock, Gary; Reilly, James; Graetz, Jason; Wegrzyn, James E.

2010-11-23

In one aspect, the invention relates to activated aluminum hydride hydrogen storage compositions containing aluminum hydride in the presence of, or absence of, hydrogen desorption stimulants. The invention particularly relates to such compositions having one or more hydrogen desorption stimulants selected from metal hydrides and metal aluminum hydrides. In another aspect, the invention relates to methods for generating hydrogen from such hydrogen storage compositions.

METHOD AND APPARATUS FOR MAKING URANIUM-HYDRIDE COMPACTS

DOEpatents

Wellborn, W.; Armstrong, J.R.

1959-03-10

A method and apparatus are presented for making compacts of pyrophoric hydrides in a continuous operation out of contact with air. It is particularly useful for the preparation of a canned compact of uranium hydride possessing high density and purity. The metallic uranium is enclosed in a container, positioned in a die body evacuated and nvert the uranium to the hydride is admitted and the container sealed. Heat is applied to bring about the formation of the hydride, following which compression is used to form the compact sealed in a container ready for use.

Non-intrusive refrigerant charge indicator

DOEpatents

Mei, Viung C.; Chen, Fang C.; Kweller, Esher

2005-03-22

A non-intrusive refrigerant charge level indicator includes a structure for measuring at least one temperature at an outside surface of a two-phase refrigerant line section. The measured temperature can be used to determine the refrigerant charge status of an HVAC system, and can be converted to a pressure of the refrigerant in the line section and compared to a recommended pressure range to determine whether the system is under-charged, properly charged or over-charged. A non-intrusive method for assessing the refrigerant charge level in a system containing a refrigerant fluid includes the step of measuring a temperature at least one outside surface of a two-phase region of a refrigerant containing refrigerant line, wherein the temperature measured can be converted to a refrigerant pressure within the line section.

Use of reversible hydrides for hydrogen storage

NASA Technical Reports Server (NTRS)

Darriet, B.; Pezat, M.; Hagenmuller, P.

1980-01-01

The addition of metals or alloys whose hydrides have a high dissociation pressure allows a considerable increase in the hydrogenation rate of magnesium. The influence of temperature and hydrogen pressure on the reaction rate were studied. Results concerning the hydriding of magnesium rich alloys such as Mg2Ca, La2Mg17 and CeMg12 are presented. The hydriding mechanism of La2Mg17 and CeMg12 alloys is given.

Results of NDE Technique Evaluation of Clad Hydrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunerth, Dennis C.

2014-09-01

This report fulfills the M4 milestone, M4FT-14IN0805023, Results of NDE Technique Evaluation of Clad Hydrides, under Work Package Number FT-14IN080502. During service, zirconium alloy fuel cladding will degrade via corrosion/oxidation. Hydrogen, a byproduct of the oxidation process, will be absorbed into the cladding and eventually form hydrides due to low hydrogen solubility limits. The hydride phase is detrimental to the mechanical properties of the cladding and therefore it is important to be able to detect and characterize the presence of this constituent within the cladding. Presently, hydrides are evaluated using destructive examination. If nondestructive evaluation techniques can be used tomore » detect and characterize the hydrides, the potential exists to significantly increase test sample coverage while reducing evaluation time and cost. To demonstrate the viability this approach, an initial evaluation of eddy current and ultrasonic techniques were performed to demonstrate the basic ability to these techniques to detect hydrides or their effects on the microstructure. Conventional continuous wave eddy current techniques were applied to zirconium based cladding test samples thermally processed with hydrogen gas to promote the absorption of hydrogen and subsequent formation of hydrides. The results of the evaluation demonstrate that eddy current inspection approaches have the potential to detect both the physical damage induced by hydrides, e.g. blisters and cracking, as well as the combined effects of absorbed hydrogen and hydride precipitates on the electrical properties of the zirconium alloy. Similarly, measurements of ultrasonic wave velocities indicate changes in the elastic properties resulting from the combined effects of absorbed hydrogen and hydride precipitates as well as changes in geometry in regions of severe degradation. However, for both approaches, the signal responses intended to make the desired measurement incorporate a number of

Hydride affinity scale of various substituted arylcarbeniums in acetonitrile.

PubMed

Zhu, Xiao-Qing; Wang, Chun-Hua

2010-12-23

Combined with the integral equation formalism polarized continuum model (IEFPCM), the hydride affinities of 96 various acylcarbenium ions in the gas phase and CH(3)CN were estimated by using the B3LYP/6-31+G(d)//B3LYP/6-31+G(d), B3LYP/6-311++G(2df,2p)//B3LYP/6-31+G(d), and BLYP/6-311++G(2df,2p)//B3LYP/6-31+G(d) methods for the first time. The results show that the combination of the BLYP/6-311++G(2df,2p)//B3LYP/6-31+G(d) method and IEFPCM could successfully predict the hydride affinities of arylcarbeniums in MeCN with a precision of about 3 kcal/mol. On the basis of the calculated results from the BLYP method, it can be found that the hydride affinity scale of the 96 arylcarbeniums in MeCN ranges from -130.76 kcal/mol for NO(2)-PhCH(+)-CN to -63.02 kcal/mol for p-(Me)(2)N-PhCH(+)-N(Me)(2), suggesting most of the arylcarbeniums are good hydride acceptors. Examination of the effect of the number of phenyl rings attached to the carbeniums on the hydride affinities shows that the increase of the hydride affinities takes place linearly with increasing number of benzene rings in the arylcarbeniums. Analyzing the effect of the substituents on the hydride affinities of arylcarbeniums indicates that electron-donating groups decrease the hydride affinities and electron-withdrawing groups show the opposite effect. The hydride affinities of arylcarbeniums are linearly dependent on the sum of the Hammett substituent parameters σ(p)(+). Inspection of the correlation of the solution-phase hydride affinities with gas-phase hydride affinities and aqueous-phase pK(R)(+) values reveals a remarkably good correspondence of ΔG(H(-)A)(R(+)) with both the gas-phase relative hydride affinities only if the α substituents X have no large electron-donating or -withdrawing properties and the pK(R)(+) values even though the media are dramatically different. The solution-phase hydride affinities also have a linear relationship with the electrophilicity parameter E, and this dependence can

Kelvin waves: a comparison study between SABER and normal mode analysis of ECMWF data

NASA Astrophysics Data System (ADS)

Blaauw, Marten; Garcia, Rolando; Zagar, Nedjeljka; Tribbia, Joe

2014-05-01

Equatorial Kelvin waves spectra are sensitive to the multi-scale variability of their source of tropical convective forcing. Moreover, Kelvin wave spectra are modified upward by changes in the background winds and stability. Recent high resolution data from observations as well as analyses are capable of resolving the slower Kelvin waves with shorter vertical wavelength near the tropical tropopause. In this presentation, results from a quantitive comparison study of stratospheric Kelvin waves in satellite data (SABER) and analysis data from the ECMWF operational archive will be shown. Temperature data from SABER is extracted over a six year period (2007-2012) with an effective vertical resolution of 2 km. Spectral power of stratospheric Kelvin waves in SABER data is isolated by selecting symmetric and eastward spectral components in the 8-20 days range. Global data from ECMWF operational analysis is extracted for the same six years on 91 model levels (top level at 0.01 hPa) and 25 km horizontal resolution. Using three-dimensional orthogonal normal-mode expansions, the input mass and wind data from ECMWF is projected onto balanced rotational modes and unbalanced inertia-gravity modes, including spectral data for pure Kelvin waves. The results show good agreement between Kelvin waves in SABER and ECMWF analyses data for: (i) the frequency shift of Kelvin wave variance with height and (ii) vertical wavelengths. Variability with respect to QBO will also be discussed. In a previous study, discrepancies in the upper stratosphere were found to be 60% and are found here to be 10% (8-20 day averaged value), which can be explained by the better stratosphere representation in the 91 model level version of the ECMWF operational model. New discrepancies in Kelvin wave variance are found in the lower stratosphere at 20 km. Averaged spectral power over the 8-20 day range is found to be 35% higher in ECMWF compared to SABER data. We compared results at 20 km with additional

Kelvin-wave cascade in the vortex filament model

NASA Astrophysics Data System (ADS)

Baggaley, Andrew W.; Laurie, Jason

2014-01-01

The small-scale energy-transfer mechanism in zero-temperature superfluid turbulence of helium-4 is still a widely debated topic. Currently, the main hypothesis is that weakly nonlinear interacting Kelvin waves (KWs) transfer energy to sufficiently small scales such that energy is dissipated as heat via phonon excitations. Theoretically, there are at least two proposed theories for Kelvin-wave interactions. We perform the most comprehensive numerical simulation of weakly nonlinear interacting KWs to date and show, using a specially designed numerical algorithm incorporating the full Biot-Savart equation, that our results are consistent with the nonlocal six-wave KW interactions as proposed by L'vov and Nazarenko.

Nanoindentation study of bulk zirconium hydrides at elevated temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cinbiz, Mahmut Nedim; Balooch, Mehdi; Hu, Xunxiang

Here, the mechanical properties of zirconium hydrides was studied using nano-indentation technique at a temperature range of 25 – 400 °C. Temperature dependency of reduced elastic modulus and hardness of δ- and ε-zirconium hydrides were obtained by conducting nanoindentation experiments on the bulk hydride samples with independently heating capability of indenter and heating stage. The reduced elastic modulus of δ-zirconium hydride (H/Zr ratio =1.61) decreased from ~113 GPa to ~109 GPa while temperature increased from room temperature to 400°C. For ε-zirconium hydrides (H/Zr ratio=1.79), the reduced elastic modulus decreased from 61 GPa to 54 GPa as temperature increased from roommore » temperature to 300 °C. Whereas, hardness of δ-zirconium hydride significantly decreased from 4.1 GPa to 2.41 GPa when temperature increased from room temperature to 400 °C. Similarly, hardness of ε-zirconium hydride decreased from 3.06 GPa to 2.19 GPa with temperature increase from room temperature to 300°C.« less

Nanoindentation study of bulk zirconium hydrides at elevated temperatures

DOE PAGES

Cinbiz, Mahmut Nedim; Balooch, Mehdi; Hu, Xunxiang; ...

2017-08-02

Here, the mechanical properties of zirconium hydrides was studied using nano-indentation technique at a temperature range of 25 – 400 °C. Temperature dependency of reduced elastic modulus and hardness of δ- and ε-zirconium hydrides were obtained by conducting nanoindentation experiments on the bulk hydride samples with independently heating capability of indenter and heating stage. The reduced elastic modulus of δ-zirconium hydride (H/Zr ratio =1.61) decreased from ~113 GPa to ~109 GPa while temperature increased from room temperature to 400°C. For ε-zirconium hydrides (H/Zr ratio=1.79), the reduced elastic modulus decreased from 61 GPa to 54 GPa as temperature increased from roommore » temperature to 300 °C. Whereas, hardness of δ-zirconium hydride significantly decreased from 4.1 GPa to 2.41 GPa when temperature increased from room temperature to 400 °C. Similarly, hardness of ε-zirconium hydride decreased from 3.06 GPa to 2.19 GPa with temperature increase from room temperature to 300°C.« less

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... transparent or solid doors, sliding or hinged doors, a combination of hinged, sliding, transparent, or solid... compressors, refrigerant condensers, condenser fans and motors, and factory supplied accessories. Self... more refrigerant compressors, refrigerant condensers, condenser fans and motors, and factory supplied...

Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode

NASA Astrophysics Data System (ADS)

Sreenivas, Bura; Nayak, H. Gurudath; Venkatarathnam, G.

2017-01-01

The composition of the refrigerant mixture in circulation during steady state operation of J-T and allied refrigerators is not the same as that charged due to liquid hold up in the heat exchangers and phase separators, as well as the differential solubility of different refrigerant components in the compressor lubricating oil. The performance of refrigerators/liquefiers operating on mixed refrigerant cycles is dependent on the mixture composition. It is therefore important to charge the right mixture that results in an optimum composition in circulation during steady state operation. The relationship between the charged and circulating composition has been experimentally studied in a J-T refrigerator operating in the liquid refrigerant supply (LRS) mode and an auto refrigerant cascade refrigerator (with a phase separator) operating in the gas refrigerant supply (GRS) mode. The results of the study are presented in this work. The results show that the method presented earlier for J-T refrigerators operating in GRS mode is also applicable in the case of refrigerators studied in this work.

Chemical Hydride Slurry for Hydrogen Production and Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClaine, Andrew W

2008-09-30

The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH 2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at amore » time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of $4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston University

The effect of stress state on zirconium hydride reorientation

NASA Astrophysics Data System (ADS)

Cinbiz, Mahmut Nedim

Prior to storage in a dry-cask facility, spent nuclear fuel must undergo a vacuum drying cycle during which the spent fuel rods are heated up to elevated temperatures of ≤ 400°C to remove moisture the canisters within the cask. As temperature increases during heating, some of the hydride particles within the cladding dissolve while the internal gas pressure in fuel rods increases generating multi-axial hoop and axial stresses in the closed-end thin-walled cladding tubes. As cool-down starts, the hydrogen in solid solution precipitates as hydride platelets, and if the multiaxial stresses are sufficiently large, the precipitating hydrides reorient from their initial circumferential orientation to radial orientation. Radial hydrides can severely embrittle the spent nuclear fuel cladding at low temperature in response to hoop stress loading. Because the cladding can experience a range of stress states during the thermo-mechanical treatment induced during vacuum drying, this study has investigated the effect of stress state on the process of hydride reorientation during controlled thermo-mechanical treatments utilizing the combination of in situ X-ray diffraction and novel mechanical testing analyzed by the combination of metallography and finite element analysis. The study used cold worked and stress relieved Zircaloy-4 sheet containing approx. 180 wt. ppm hydrogen as its material basis. The failure behavior of this material containing radial hydrides was also studied over a range of temperatures. Finally, samples from reactor-irradiated cladding tubes were examined by X-ray diffraction using synchrotron radiation. To reveal the stress state effect on hydride reorientation, the critical threshold stress to reorient hydrides was determined by designing novel mechanical test samples which produce a range of stress states from uniaxial to "near-equibiaxial" tension when a load is applied. The threshold stress was determined after thermo-mechanical treatments by

Refrigeration-Induced Binding of von Willebrand Factor Facilitates Fast Clearance of Refrigerated Platelets.

PubMed

Chen, Wenchun; Druzak, Samuel A; Wang, Yingchun; Josephson, Cassandra D; Hoffmeister, Karin M; Ware, Jerry; Li, Renhao

2017-12-01

Apheresis platelets for transfusion treatment are currently stored at room temperature because after refrigeration platelets are rapidly cleared on transfusion. In this study, the role of von Willebrand factor (VWF) in the clearance of refrigerated platelets is addressed. Human and murine platelets were refrigerated in gas-permeable bags at 4°C for 24 hours. VWF binding, platelet signaling events, and platelet post-transfusion recovery and survival were measured. After refrigeration, the binding of plasma VWF to platelets was drastically increased, confirming earlier studies. The binding was blocked by peptide OS1 that bound specifically to platelet glycoprotein (GP)Ibα and was absent in VWF - / - plasma. Although surface expression of GPIbα was reduced after refrigeration, refrigeration-induced VWF binding under physiological shear induced unfolding of the GPIbα mechanosensory domain on the platelet, as evidenced by increased exposure of a linear epitope therein. Refrigeration and shear treatment also induced small elevation of intracellular Ca 2+ , phosphatidylserine exposure, and desialylation of platelets, which were absent in VWF -/- platelets or inhibited by OS1, which is a monomeric 11-residue peptide (CTERMALHNLC). Furthermore, refrigerated VWF -/- platelets displayed increased post-transfusion recovery and survival than wild-type ones. Similarly, adding OS1 to transgenic murine platelets expressing only human GPIbα during refrigeration improved their post-transfusion recovery and survival. Refrigeration-induced binding of VWF to platelets facilitates their rapid clearance by inducing GPIbα-mediated signaling. Our results suggest that inhibition of the VWF-GPIbα interaction may be a potential strategy to enable refrigeration of platelets for transfusion treatment. © 2017 American Heart Association, Inc.

Hydride heat pump with heat regenerator

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor)

1991-01-01

A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

Properties of Gas Mixtures and Their Use in Mixed-Refrigerant Joule-Thomson Refrigerators

NASA Astrophysics Data System (ADS)

Luo, E.; Gong, M.; Wu, J.; Zhou, Y.

2004-06-01

The Joule-Thomson (J-T) effect has been widely used for achieving low temperatures. In the past few years, much progress has been made in better understanding the working mechanism of the refrigeration method and in developing prototypes for different applications. In this talk, there are three aspects of our research work to be discussed. First, some special thermal properties of the mixtures for achieving liquid nitrogen temperature range will be presented. Secondly, some important conclusions from the optimization of various mixed-refrigerant J-T cycles such as a simple J-T cycle and an auto-cascade mixed-refrigerant J-T cycle will be presented. Moreover, an auto-cascade, mixed-refrigerant J-T refrigerator with a special mixture capable of achieving about 50K will be mentioned. Finally, various prototypes based on the mixed-refrigerant refrigeration technology will be described. These applications include miniature J-T cryocoolers for cooling infrared detectors and high-temperature superconducting devices, cryosurgical knife for medical treatment, low-temperature refrigerators for biological storage and so forth. The on-going research work and unanswered questions for this technology will be also discussed.

Refrigerants and environment

NASA Astrophysics Data System (ADS)

Tsvetkov, O. B.; Laptev, Yu A.

2017-11-01

The refrigeration and air-conditioning industries are important sectors of the economy and represents about 15 % of global electricity consumptions. The chlorofluorocarbons also called CFCs are a class of refrigerants containing the halogens chlorine and/or fluorine on a carbon skeleton. Because of their environmental impact the Montreal Protocol was negotiated in 1987 to limit the production of certain CFCs and hydrochlirofluorocarbons (HCFCs) in developed and developing countries. The halogenated refrigerants are depleting the ozone layer also major contribution to the greenhouse effect. To be acceptable as a refrigerant a fluid must satisfy a variety of thermodynamic criteria and should be environment friendly with zero Ozone Depletion Potential and low Global Warming Potential. The perspective of a future phase down of HFCs is considered in this report taking into account a strategy for the phase out of HCFCs and perspective of choosing of various refrigerant followed by safety issues.

High pressure hydriding of sponge-Zr in steam-hydrogen mixtures

NASA Astrophysics Data System (ADS)

Soo Kim, Yeon; Wang, Wei-E.; Olander, D. R.; Yagnik, S. K.

1997-07-01

Hydriding kinetics of thin sponge-Zr layers metallurgically bonded to a Zircaloy disk has been studied by thermogravimetry in the temperature range 350-400°C in 7 MPa hydrogen-steam mixtures. Some specimens were prefilmed with a thin oxide layer prior to exposure to the reactant gas; all were coated with a thin layer of gold to avoid premature reaction at edges. Two types of hydriding were observed in prefilmed specimens, viz., a slow hydrogen absorption process that precedes an accelerated (massive) hydriding. At 7 MPa total pressure, the critical ratio of H 2/H 2O above which massive hydriding occurs at 400°C is ˜ 200. The critical H 2/H 20 ratio is shifted to ˜2.5 × 103 at 350°C. The slow hydriding process occurs only when conditions for hydriding and oxidation are approximately equally favorable. Based on maximum weight gain, the specimen is completely converted to δ-ZrH 2 by massive hydriding in ˜5 h at a hydriding rate of ˜10 -6 mol H/cm 2 s. Incubation times of 10-20 h prior to the onset of massive hydriding increases with prefilm oxide thickness in the range of 0-10 μm. By changing to a steam-enriched gas, massive hydriding that initially started in a steam-starved condition was arrested by re-formation of a protective oxide scale.

Storing hydrogen in the form of light alloy hydrides

NASA Technical Reports Server (NTRS)

Freund, E.; Gillerm, C.

1981-01-01

Different hydrides are investigated to find a system with a sufficiently high storage density (at least 3%). The formation of hydrides with light alloys is examined. Reaction kinetics for hydride formation were defined and applied to the systems Mg-Al-H, Mg-Al-Cu-H, Ti-Al-H, Ti-Al-Cu-H, and Ti-Al-Ni-H. Results indicate that the addition of Al destabilizes MgH2 and TiH2 hydrides while having only a limited effect on the storage density.

1. VIEW OF A PORTION OF THE HYDRIDE PROCESSING LABORATORY. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW OF A PORTION OF THE HYDRIDE PROCESSING LABORATORY. OPERATIONS IN THE GLOVE BOX IN THE BACKGROUND OF THE PHOTOGRAPH INCLUDED HYDRIDING OF PLUTONIUM AND HYDRIDE SEPARATION. IN THE FOREGROUND, THE VACUUM MONITOR CONTROL PANEL MEASURED TEMPERATURES WITHIN THE GLOVEBOX. THE CENTER CONTROL PANEL REGULATED THE FURNACE INSIDE THE GLOVE BOX USED IN THE HYDRIDING PROCESSES. THIS EQUIPMENT WAS ESSENTIAL TO THE HYDRIDING PROCESS, AS WELL AS OTHER GLOVE BOX OPERATIONS. - Rocky Flats Plant, Plutonium Laboratory, North-central section of industrial area at 79 Drive, Golden, Jefferson County, CO

Specific heats of lunar surface materials from 90 to 350 degrees Kelvin

USGS Publications Warehouse

Robie, R.A.; Hemingway, B.S.; Wilson, W.H.

1970-01-01

The specific heats of lunar samples 10057 and 10084 returned by the Apollo 11 mission have been measured between 90 and 350 degrees Kelvin by use of an adiabatic calorimeter. The samples are representative of type A vesicular basalt-like rocks and of finely divided lunar soil. The specific heat of these materials changes smoothly from about 0.06 calorie per gram per degree at 90 degrees Kelvin to about 0.2 calorie per gram per degree at 350 degrees Kelvin. The thermal parameter ??=(k??C)-1/2 for the lunar surface will accordingly vary by a factor of about 2 between lunar noon and midnight.

METHOD OF FABRICATING A URANIUM-ZIRCONIUM HYDRIDE REACTOR CORE

DOEpatents

Weeks, I.F.; Goeddel, W.V.

1960-03-22

A method is described of evenly dispersing uranlum metal in a zirconium hydride moderator to produce a fuel element for nuclear reactors. According to the invention enriched uranium hydride and zirconium hydride powders of 200 mesh particle size are thoroughly admixed to form a mixture containing 0.1 to 3% by weight of U/sup 235/ hydride. The mixed powders are placed in a die and pressed at 100 tons per square inch at room temperature. The resultant compacts are heated in a vacuum to 300 deg C, whereby the uranium hydride deoomposes into uranium metal and hydrogen gas. The escaping hydrogen gas forms a porous matrix of zirconium hydride, with uramum metal evenly dispersed therethrough. The advantage of the invention is that the porosity and uranium distribution of the final fuel element can be more closely determined and controlled than was possible using prior methods of producing such fuel ele- ments.

Bipolar Nickel-Metal Hydride Battery Being Developed

NASA Technical Reports Server (NTRS)

Manzo, Michelle A.

1998-01-01

The NASA Lewis Research Center has contracted with Electro Energy, Inc., to develop a bipolar nickel-metal hydride battery design for energy storage on low-Earth-orbit satellites. The objective of the bipolar nickel-metal hydride battery development program is to approach advanced battery development from a systems level while incorporating technology advances from the lightweight nickel electrode field, hydride development, and design developments from nickel-hydrogen systems. This will result in a low-volume, simplified, less-expensive battery system that is ideal for small spacecraft applications. The goals of the program are to develop a 1-kilowatt, 28-volt (V), bipolar nickel-metal hydride battery with a specific energy of 100 watt-hours per kilogram (W-hr/kg), an energy density of 250 W-hr/liter and a 5-year life in low Earth orbit at 40-percent depth-of-discharge.

ORNL Interim Progress Report on Hydride Reorientation CIRFT Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An John; Yan, Yong; Wang, Hong

A systematic study of H. B. Robinson (HBR) high burnup spent nuclear fuel (SNF) vibration integrity was performed in Phase I project under simulated transportation environments, using the Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT) hot cell testing technology developed at Oak Ridge National Laboratory in 2013–14. The data analysis on the as-irradiated HBR SNF rods demonstrated that the load amplitude is the dominant factor that controls the fatigue life of bending rods. However, previous studies have shown that the hydrogen content and hydride morphology has an important effect on zirconium alloy mechanical properties. To address the effect of radial hydridesmore » in SNF rods, in Phase II a test procedure was developed to simulate the effects of elevated temperatures, pressures, and stresses during transfer-drying operations. Pressurized and sealed fuel segments were heated to the target temperature for a preset hold time and slow-cooled at a controlled rate. The procedure was applied to both non-irradiated/prehydrided and high-burnup Zircaloy-4 fueled cladding segments using the Nuclear Regulatory Commission-recommended 400°C maximum temperature limit at various cooling rates. Before testing high-burnup cladding, four out-of-cell tests were conducted to optimize the hydride reorientation (R) test condition with pre-hydride Zircaloy-4 cladding, which has the same geometry as the high burnup fuel samples. Test HR-HBR#1 was conducted at the maximum hoop stress of 145 MPa, at a 400°C maximum temperature and a 5°C/h cooling rate. On the other hand, thermal cycling was performed for tests HR-HBR#2, HR-HBR#3, and HR-HBR#4 to generate more radial hydrides. It is clear that thermal cycling increases the ratio of the radial hydride to circumferential hydrides. The internal pressure also has a significant effect on the radial hydride morphology. This report describes a procedure and experimental results of the four out-of-cell hydride reorientation

In situ hydride formation in titanium during focused ion milling.

PubMed

Ding, Rengen; Jones, Ian P

2011-01-01

It is well known that titanium and its alloys are sensitive to electrolytes and thus hydrides are commonly observed in electropolished foils. In this study, focused ion beam (FIB) milling was used to prepare thin foils of titanium and its alloys for transmission electron microscopy. The results show the following: (i) titanium hydrides were observed in pure titanium, (ii) the preparation of a bulk sample in water or acid solution resulted in the formation of more hydrides and (iii) FIB milling aids the precipitation of hydrides, but there were never any hydrides in Ti64 and Ti5553.

Managing Refrigerant Emissions

EPA Pesticide Factsheets

Access information on EPA's efforts to address ozone layer depletion by reducing emissions of refrigerants from stationary refrigeration and air conditioning systems and motor vehicle air conditioning systems.

Low density metal hydride foams

DOEpatents

Maienschein, Jon L.; Barry, Patrick E.

1991-01-01

Disclosed is a low density foam having a porosity of from 0 to 98% and a density less than about 0.67 gm/cc, prepared by heating a mixture of powered lithium hydride and beryllium hydride in an inert atmosphere at a temperature ranging from about 455 to about 490 K for a period of time sufficient to cause foaming of said mixture, and cooling the foam thus produced. Also disclosed is the process of making the foam.

SPICA sub-Kelvin cryogenic chains

NASA Astrophysics Data System (ADS)

Duband, L.; Duval, J. M.; Luchier, N.; Prouve, T.

2012-04-01

SPICA, a Japanese led mission, is part of the JAXA future science program and is planned for launch in 2018. SPICA will perform imaging and spectroscopic observations in the mid- and far-IR waveband, and is developing instrumentation spanning the 5-400 μm range. The SPICA payload features several candidate instruments, some of them requiring temperature down to 50 mK. This is currently the case for SAFARI, a core instrument developed by a European-based consortium, and BLISS proposed by CALTECH/JPL in the US. SPICA's distinctive feature is to actively cool its telescope to below 6 K. In addition, SPICA is a liquid cryogen free satellite and all the cooling will be provided by radiative cooling (L2 orbit) down to 30 K and by mechanical coolers for lower temperatures. The satellite will launch warm and slowly equilibrate to its operating temperatures once in orbit. This warm launch approach makes it possible to eliminate a large liquid cryogen tank and to use the mass saved to launch a large diameter telescope (3.2 m). This 4 K cooled telescope significantly reduces its own thermal radiation, offering superior sensitivity in the infrared region. The cryogenic system that enables this warm launch/cooled telescope concept is a key issue of the mission. This cryogenic chain features a number of cooling stages comprising passive radiators, Stirling coolers and several Joule Thomson loops, offering cooling powers at typically 20, 4.5, 2.5 and 1.7 K. The SAFARI and BLISS detectors require cooling to temperatures as low as 50 mK. The instrument coolers will be operated from these heat sinks. They are composed of a small demagnetization refrigerator (ADR) pre cooled by either a single or a double sorption cooler, respectively for SAFARI and BLISS. The BLISS cooler maintains continuous cooling at 300 mK and thus suppresses the thermal equilibrium time constant of the large focal plane. These hybrid architectures allow designing low weight coolers able to reach 50 mK. Because

Method of making crack-free zirconium hydride

DOEpatents

Sullivan, Richard W.

1980-01-01

Crack-free hydrides of zirconium and zirconium-uranium alloys are produced by alloying the zirconium or zirconium-uranium alloy with beryllium, or nickel, or beryllium and scandium, or nickel and scandium, or beryllium and nickel, or beryllium, nickel and scandium and thereafter hydriding.

46 CFR 147.90 - Refrigerants.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Refrigerants. 147.90 Section 147.90 Shipping COAST GUARD... Special Requirements for Particular Materials § 147.90 Refrigerants. (a) Only refrigerants listed in ANSI/ASHRAE 34-78 may be carried as ships' stores. (b) Refrigerants contained in a vessel's operating system...

46 CFR 147.90 - Refrigerants.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Refrigerants. 147.90 Section 147.90 Shipping COAST GUARD... Special Requirements for Particular Materials § 147.90 Refrigerants. (a) Only refrigerants listed in ANSI/ASHRAE 34-78 may be carried as ships' stores. (b) Refrigerants contained in a vessel's operating system...

COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

NASA Technical Reports Server (NTRS)

Westra, Douglas G.

1993-01-01

With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

Magnetic refrigeration for maser amplifier cooling

NASA Technical Reports Server (NTRS)

Johnson, D. L.

1982-01-01

The development of a multifrequency upconverter-maser system for the DSN has created the need to develop a closed-cycle refrigerator (CCR) capable of providing more than 3 watts of refrigeration capability at 4.5 K. In addition, operating concerns such as the high cost of electrical power consumption and the loss of maser operation due to CCR failures require that improvements be made to increase the efficiency and reliability of the CCR. One refrigeration method considered is the replacement of the Joule-Thomson expansion circuit with a magnetic refrigeration. Magnetic refrigerators can provide potentially reliable and highly efficient refrigeration at a variety of temperature ranges and cooling power. The concept of magnetic refrigeration is summarized and a literature review of existing magnetic refrigerator designs which have been built and tested and that may also be considered as possibilities as a 4 K to 15 K magnetic refrigeration stage for the DSN closed-cycle refrigerator is provided.

ARTI Refrigerant Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

High H⁻ ionic conductivity in barium hydride.

PubMed

Verbraeken, Maarten C; Cheung, Chaksum; Suard, Emmanuelle; Irvine, John T S

2015-01-01

With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H(-)) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm(-1) at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.

Reactivity of yttrium carboxylates toward alkylaluminum hydrides.

PubMed

Schädle, Christoph; Fischbach, Andreas; Herdtweck, Eberhardt; Törnroos, Karl W; Anwander, Reiner

2013-11-25

Yttrocene-carboxylate complex [Cp*2Y(OOCAr(Me))] (Cp*=C5Me5, Ar(Me) =C6H2Me3-2,4,6) was synthesized as a spectroscopically versatile model system for investigating the reactivity of alkylaluminum hydrides towards rare-earth-metal carboxylates. Equimolar reactions with bis-neosilylaluminum hydride and dimethylaluminum hydride gave adduct complexes of the general formula [Cp*2Y(μ-OOCAr(Me))(μ-H)AlR2] (R=CH2SiMe3, Me). The use of an excess of the respective aluminum hydride led to the formation of product mixtures, from which the yttrium-aluminum-hydride complex [{Cp*2Y(μ-H)AlMe2(μ-H)AlMe2(μ-CH3)}2] could be isolated, which features a 12-membered-ring structure. The adduct complexes [Cp*2Y(μ-OOCAr(Me))(μ-H)AlR2] display identical (1)J(Y,H) coupling constants of 24.5 Hz for the bridging hydrido ligands and similar (89)Y NMR shifts of δ=-88.1 ppm (R=CH2SiMe3) and δ=-86.3 ppm (R=Me) in the (89)Y DEPT45 NMR experiments. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental Investigation of COP Using Hydro Carbon Refrigerant in a Domestic Refrigerator

NASA Astrophysics Data System (ADS)

Peyyala, Anusha; Sudheer, N. V. V. S., Dr

2017-08-01

Under the Montreal protocol 1987 researchers worked on the possibility of alternative refrigerants like Hydroflourocarbon’s [HFC’s] and Hydrocarbon’s[HC’s] to replace refrigerants Chloroflourocarbon’s [CFC’s] and Hydrochlorofluorocarbons [HCFC’s] in air-conditioning and cooling systems that are destroying the ozone layer. On October 15, 2016 one hundred and ninety plus countries including India came to an agreement called Kigali Amendment to phase out potent green house gases by 2045 there by preventing 0.5 C rise in global temperature by 2050. Under this agreement India agreed to a timeline to reduce the use of HFC’s by 85% of their baseline by 2045. HFC’s are a family of greenhouse gases that are largely used in refrigerators and air conditioners which have reduced the Ozone Depleting Potential [ODP] but increased the Global Warming Potential [GWP]. Refrigeration and its applications are important in almost all branches of industry, so engineers have to become aware of its principles, uses and limitations. Since the decade there are major changes in the choice of refrigerants due to environmental factors. This issue is on-going and new developments should be developed to decrease the environmental problems. So the aim of this paper is to present the experimental analysis of Coefficient of performance [COP] values using R134a [HFC] & R600a [HC] as Refrigerants in Domestic refrigerator using conventional and nonconventional energy sources. Based on the results, usage of R600a in domestic refrigerators will reduce the ODP and also GWP problems which fulfills the nominal requirements of human beings without any effects.

Low-temperature magnetic refrigerator

DOEpatents

Barclay, J.A.

1983-05-26

The invention relates to magnetic refrigeration and more particularly to low temperature refrigeration between about 4 and about 20 K, with an apparatus and method utilizing a belt of magnetic material passed in and out of a magnetic field with heat exchangers within and outside the field operably disposed to accomplish refrigeration.

Kelvin-Helmholtz versus Hall magnetoshear instability in astrophysical flows.

PubMed

Gómez, Daniel O; Bejarano, Cecilia; Mininni, Pablo D

2014-05-01

We study the stability of shear flows in a fully ionized plasma. Kelvin-Helmholtz is a well-known macroscopic and ideal shear-driven instability. In sufficiently low-density plasmas, also the microscopic Hall magnetoshear instability can take place. We performed three-dimensional simulations of the Hall-magnetohydrodynamic equations where these two instabilities are present, and carried out a comparative study. We find that when the shear flow is so intense that its vorticity surpasses the ion-cyclotron frequency of the plasma, the Hall magnetoshear instability is not only non-negligible, but it actually displays growth rates larger than those of the Kelvin-Helmholtz instability.

Kelvin-Helmholtz instability in a single-component atomic superfluid

NASA Astrophysics Data System (ADS)

Baggaley, A. W.; Parker, N. G.

2018-05-01

We demonstrate an experimentally feasible method for generating the classical Kelvin-Helmholtz instability in a single-component atomic Bose-Einstein condensate. By progressively reducing a potential barrier between two counterflowing channels, we seed a line of quantized vortices, which precede to form progressively larger clusters, mimicking the classical roll-up behavior of the Kelvin-Helmholtz instability. This cluster formation leads to an effective superfluid shear layer, formed through the collective motion of many quantized vortices. From this we demonstrate a straightforward method to measure the effective viscosity of a turbulent quantum fluid in a system with a moderate number of vortices, within the range of current experimental capabilities.

Applicability of ASST-A helium refrigeration system for JLab End Station Refrigerator

NASA Astrophysics Data System (ADS)

Hasan, N.; Knudsen, P.; Ganni, V.

2017-12-01

The MØLLER experiment at Jefferson Lab (JLab) is a high power (5 kW) liquid hydrogen target scheduled to be operational in the 12 GeV-era. At present, cryogenic loads and targets at three of JLab’s four experimental halls are supported by the End Station Refrigerator (ESR) - a CTI/Helix 1.5 kW 4.5 K refrigerator. It is not capable of supporting the high power target load and a capacity upgrade of the ESR cryogenic system is essential. The ASST-A helium refrigeration system is a 4 kW 4.5 K refrigerator. It was designed and used for the Superconducting Super Collider Lab (SSCL) magnet string test and later obtained by JLab after the cancellation of that project. The modified ASST-A refrigeration system, which will be called ESR-II along with a support flow from JLab’s Central Helium Liquefier (CHL) is considered as an option for the End Station Refrigerator capacity upgrade. The applicability of this system for ESR-II under varying load conditions is investigated. The present paper outlines the findings of this process study.

Thermodynamic Analysis of a Mixed Refrigerant Ejector Refrigeration Cycle Operating with Two Vapor-liquid Separators

NASA Astrophysics Data System (ADS)

Tan, Yingying; Chen, Youming; Wang, Lin

2018-06-01

A mixed refrigerant ejector refrigeration cycle operating with two-stage vapor-liquid separators (MRERC2) is proposed to obtain refrigeration temperature at -40°C. The thermodynamic investigations on performance of MRERC2 using zeotropic mixture refrigerant R23/R134a are performed, and the comparisons of cycle performance between MRERC2 and MRERC1 (MRERC with one-stage vapor-liquid separator) are conducted. The results show that MRERC2 can achieve refrigeration temperature varying between -23.9°C and -42.0°C when ejector pressure ratio ranges from 1.6 to 2.3 at the generation temperature of 57.3-84.9°C. The parametric analysis indicates that increasing condensing temperature decreases coefficient of performance ( COP) of MRERC2, and increasing ejector pressure ratio and mass fraction of the low boiling point component in the mixed refrigerant can improve COP of MRERC2. The MRERC2 shows its potential in utilizing low grade thermal energy as driving power to obtain low refrigeration temperature for the ejector refrigeration cycle.

Erratum: SDO-AIA Observation of Kelvin-helmholtz Instability in the Solar Corona

NASA Technical Reports Server (NTRS)

Ofman, Leon; Thompson, Barbara J.

2012-01-01

The first SDOAIA observation of the KelvinHelmholtz instability in the solar corona in the 2010 April 8 event was reported by Ofman Thompson (2010, 2011). Foullon et al. (2011), which was published prior to Ofman Thompson (2011), claimed the detection of the KelvinHelmholtz instability in a later event (2010 November 3), and should have been cited in Ofman Thompson (2011).

A study of alternative refrigerants for the refrigeration and air conditioning sector in Mauritius

NASA Astrophysics Data System (ADS)

Dreepaul, R. K.

2017-11-01

The most frequently used refrigerants in the refrigeration and air conditioning (RAC) sector in Mauritius are currently hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC). However, because of their strong influence on global warming and the impact of HCFCs on the ozone layer, refrigerants such as ammonia (NH3), carbon dioxide (CO2) and Hydrocarbons (HC), having minimal impact on the environment, are being considered. So far, HCs have only been safely used in domestic refrigeration. Ammonia has been used mainly for industrial refrigeration whereas CO2 is still under study. In this paper, a comparative study of the various feasible alternatives is presented in a survey that was undertaken with major stake holders in the field. The retrofitting possibility of existing equipment was assessed and safety issues associated with each refrigerant were analysed. The major setback of hydrocarbons as a widely accepted refrigerant is its flammability which was considered as a major safety hazard by the majority of respondents in the survey and the main advantages are the improved equipment coefficient of performance (COP) and better TEWI factor. This resulted in a 12 % drop in energy consumption. Despite the excellent thermodynamic properties of ammonia, its use has mainly been confined to industrial refrigeration due to its toxicity. In Mauritius, the performance of ammonia in air conditioning is being evaluated on a pilot basis. The major setback of carbon dioxide as a refrigerant is the high operating pressure which is considered a safety hazard. The high initial investment cost and the lack of qualified maintenance technician is also an issue. The use of CO2 is mainly being considered in the commercial refrigeration sector.

Exact solution for the energy spectrum of Kelvin-wave turbulence in superfluids

NASA Astrophysics Data System (ADS)

Boué, Laurent; Dasgupta, Ratul; Laurie, Jason; L'Vov, Victor; Nazarenko, Sergey; Procaccia, Itamar

2011-08-01

We study the statistical and dynamical behavior of turbulent Kelvin waves propagating on quantized vortices in superfluids and address the controversy concerning the energy spectrum that is associated with these excitations. Finding the correct energy spectrum is important because Kelvin waves play a major role in the dissipation of energy in superfluid turbulence at near-zero temperatures. In this paper, we show analytically that the solution proposed by [L’vov and Nazarenko, JETP Lett.JTPLA20021-364010.1134/S002136401008014X 91, 428 (2010)] enjoys existence, uniqueness, and regularity of the prefactor. Furthermore, we present numerical results of the dynamical equation that describes to leading order the nonlocal regime of the Kelvin-wave dynamics. We compare our findings with the analytical results from the proposed local and nonlocal theories for Kelvin-wave dynamics and show an agreement with the nonlocal predictions. Accordingly, the spectrum proposed by L’vov and Nazarenko should be used in future theories of quantum turbulence. Finally, for weaker wave forcing we observe an intermittent behavior of the wave spectrum with a fluctuating dissipative scale, which we interpreted as a finite-size effect characteristic of mesoscopic wave turbulence.

ARTI Refrigerant Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cain, J.M.

1993-04-30

The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants includingmore » alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents to accelerate availability of the information and will be completed or replaced in future updates.« less

Dilution refrigeration for space applications

NASA Technical Reports Server (NTRS)

Israelsson, U. E.; Petrac, D.

1990-01-01

Dilution refrigerators are presently used routinely in ground based applications where temperatures below 0.3 K are required. The operation of a conventional dilution refrigerator depends critically on the presence of gravity. To operate a dilution refrigerator in space many technical difficulties must be overcome. Some of the anticipated difficulties are identified in this paper and possible solutions are described. A single cycle refrigerator is described conceptually that uses forces other than gravity to function and the stringent constraints imposed on the design by requiring the refrigerator to function on the earth without using gravity are elaborated upon.

Keeping Cool With Solar-Powered Refrigeration

NASA Technical Reports Server (NTRS)

2003-01-01

In the midst of developing battery-free, solar-powered refrigeration and air conditioning systems for habitats in space, David Bergeron, the team leader for NASA's Advanced Refrigerator Technology Team at Johnson Space Center, acknowledged the need for a comparable solar refrigerator that could operate in conjunction with the simple lighting systems already in place on Earth. Bergeron, a 20-year veteran in the aerospace industry, founded the company Solus Refrigeration, Inc., in 1999 to take the patented advanced refrigeration technology he co-developed with his teammate, Johnson engineer Michael Ewert, to commercial markets. Now known as SunDanzer Refrigeration, Inc., Bergeron's company is producing battery-free, photovoltaic (PV) refrigeration systems under license to NASA, and selling them globally.

Development of a component design tool for metal hydride heat pumps

NASA Astrophysics Data System (ADS)

Waters, Essene L.

Given current demands for more efficient and environmentally friendly energy sources, hydrogen based energy systems are an increasingly popular field of interest. Within the field, metal hydrides have become a prominent focus of research due to their large hydrogen storage capacity and relative system simplicity and safety. Metal hydride heat pumps constitute one such application, in which heat and hydrogen are transferred to and from metal hydrides. While a significant amount of work has been done to study such systems, the scope of materials selection has been quite limited. Typical studies compare only a few metal hydride materials and provide limited justification for the choice of those few. In this work, a metal hydride component design tool has been developed to enable the targeted down-selection of an extensive database of metal hydrides to identify the most promising materials for use in metal hydride thermal systems. The material database contains over 300 metal hydrides with various physical and thermodynamic properties included for each material. Sub-models for equilibrium pressure, thermophysical data, and default properties are used to predict the behavior of each material within the given system. For a given thermal system, this tool can be used to identify optimal materials out of over 100,000 possible hydride combinations. The selection tool described herein has been applied to a stationary combined heat and power system containing a high-temperature proton exchange membrane (PEM) fuel cell, a hot water tank, and two metal hydride beds used as a heat pump. A variety of factors can be used to select materials including efficiency, maximum and minimum system pressures, pressure difference, coefficient of performance (COP), and COP sensitivity. The targeted down-selection of metal hydrides for this system focuses on the system's COP for each potential pair. The values of COP and COP sensitivity have been used to identify pairs of highest interest for

Uranium Hydride Nucleation and Growth Model FY'16 ESC Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, Mary Ann; Richards, Andrew Walter; Holby, Edward F.

2016-12-20

Uranium hydride corrosion is of great interest to the nuclear industry. Uranium reacts with water and/or hydrogen to form uranium hydride which adversely affects material performance. Hydride nucleation is influenced by thermal history, mechanical defects, oxide thickness, and chemical defects. Information has been gathered from past hydride experiments to formulate a uranium hydride model to be used in a Canned Subassembly (CSA) lifetime prediction model. This multi-scale computer modeling effort started in FY’13, and the fourth generation model is now complete. Additional high-resolution experiments will be run to further test the model.

High Efficiency, Low Emission Refrigeration System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, Brian A.; Sharma, Vishaldeep

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the highmore » refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Methods for reducing refrigerant leakage and energy consumption are available, but underutilized. Further work needs to be done to reduce costs of advanced system designs to improve market utilization. In addition, refrigeration system retrofits that result in reduced energy consumption are needed since the majority of applications address retrofits rather than new stores. The retrofit market is also of most concern since it involves large-volume refrigerant systems with high leak rates. Finally, alternative refrigerants for new and retrofit applications are needed to reduce emissions and reduce the impact on the environment. The objective of this Collaborative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory and Hill Phoenix is to develop a supermarket refrigeration system that reduces greenhouse gas emissions and has 25 to 30 percent lower energy consumption than existing systems. The outcomes of this project will include the design of a low emission, high efficiency commercial refrigeration system suitable for use in current U.S. supermarkets. In addition, a prototype low emission, high efficiency supermarket refrigeration system will be produced

Cavitation and bubble dynamics: the Kelvin impulse and its applications

PubMed Central

Blake, John R.; Leppinen, David M.; Wang, Qianxi

2015-01-01

Cavitation and bubble dynamics have a wide range of practical applications in a range of disciplines, including hydraulic, mechanical and naval engineering, oil exploration, clinical medicine and sonochemistry. However, this paper focuses on how a fundamental concept, the Kelvin impulse, can provide practical insights into engineering and industrial design problems. The pathway is provided through physical insight, idealized experiments and enhancing the accuracy and interpretation of the computation. In 1966, Benjamin and Ellis made a number of important statements relating to the use of the Kelvin impulse in cavitation and bubble dynamics, one of these being ‘One should always reason in terms of the Kelvin impulse, not in terms of the fluid momentum…’. We revisit part of this paper, developing the Kelvin impulse from first principles, using it, not only as a check on advanced computations (for which it was first used!), but also to provide greater physical insights into cavitation bubble dynamics near boundaries (rigid, potential free surface, two-fluid interface, flexible surface and axisymmetric stagnation point flow) and to provide predictions on different types of bubble collapse behaviour, later compared against experiments. The paper concludes with two recent studies involving (i) the direction of the jet formation in a cavitation bubble close to a rigid boundary in the presence of high-intensity ultrasound propagated parallel to the surface and (ii) the study of a ‘paradigm bubble model’ for the collapse of a translating spherical bubble, sometimes leading to a constant velocity high-speed jet, known as the Longuet-Higgins jet. PMID:26442141

Investigation of Kelvin wave periods during Hai-Tang typhoon using Empirical Mode Decomposition

NASA Astrophysics Data System (ADS)

Kishore, P.; Jayalakshmi, J.; Lin, Pay-Liam; Velicogna, Isabella; Sutterley, Tyler C.; Ciracì, Enrico; Mohajerani, Yara; Kumar, S. Balaji

2017-11-01

Equatorial Kelvin waves (KWs) are fundamental components of the tropical climate system. In this study, we investigate Kelvin waves (KWs) during the Hai-Tang typhoon of 2005 using Empirical Mode Decomposition (EMD) of regional precipitation, zonal and meridional winds. For the analysis, we use daily precipitation datasets from the Global Precipitation Climatology Project (GPCP) and wind datasets from the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-analysis (ERA-Interim). As an additional measurement, we use in-situ precipitation datasets from rain-gauges over the Taiwan region. The maximum accumulated precipitation was approximately 2400 mm during the period July 17-21, 2005 over the southwestern region of Taiwan. The spectral analysis using the wind speed at 950 hPa found in the 2nd, 3rd, and 4th intrinsic mode functions (IMFs) reveals prevailing Kelvin wave periods of ∼3 days, ∼4-6 days, and ∼6-10 days, respectively. From our analysis of precipitation datasets, we found the Kelvin waves oscillated with periods between ∼8 and 20 days.

Refrigeration Showcases

NASA Technical Reports Server (NTRS)

1997-01-01

Through the Technology Affiliates Program at the Jet Propulsion Laboratory (JPL), valuable modifications were made to refrigerator displays built by Displaymor Manufacturing Company, Inc. By working with JPL, Displaymor could address stiffer requirements that ensure the freshness of foods. The application of the space technology meant that the small business would be able to continue to market its cases without incurring expenses that could threaten the viability of the business, and the future of several dozen jobs. Research and development improvements in air flow distribution and refrigeration coil technology contributed greatly to certifying Displaymor's showcases given the new federal regulations. These modifications resulted in a refrigerator case that will keep foods cooler, longer. Such changes maintained the openness of the display, critical to customer visibility and accessibility, impulse buying, and cross-merchandising.

A review of pulse tube refrigeration

NASA Technical Reports Server (NTRS)

Radebaugh, Ray

1990-01-01

This paper reviews the development of the three types of pulse tube refrigerators: basic, resonant, and orifice types. The principles of operation are given. It is shown that the pulse tube refrigerator is a variation of the Stirling-cycle refrigerator, where the moving displacer is substituted by a heat transfer mechanism or by an orifice to bring about the proper phase shifts between pressure and mass flow rate. A harmonic analysis with phasors is described which gives reasonable results for the refrigeration power, yet is simple enough to make clear the processes which give rise to the refrigeration. The efficiency and refrigeration power are compared with those of other refrigeration cycles. A brief review is given of the research being done at various laboratories on both one- and two-stage pulse tubes. A preliminary assessment of the role of pulse tube refrigerators is discussed.

Topographic coupling of surface and internal Kelvin waves. [of ocean

NASA Technical Reports Server (NTRS)

Chao, S.-Y.

1980-01-01

An analysis is presented for computing the diffraction of barotropic Kelvin waves by a localized topographical irregularity on flat-bottom ocean with an arbitrary vertical stratification. It was shown that all baroclinic Kelvin waves will be generated downstream of the bump, with the first baroclinic mode having the largest amplitude. The Poincare waves predominate in the lowest modes, and are more directionally anisotropic. It was concluded that baroclinic Poincare waves radiating offshore from the bump topography could contribute to the internal wave field in the open ocean and provide an alternative mechanism to dissipate the barotropic tides.

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... functional characteristics that affect energy consumption. Commercial refrigerator, freezer, and refrigerator... formed by the plane of the door, when the equipment is viewed in cross-section; and (2) For equipment...

The Kelvin water-drop experiment

NASA Technical Reports Server (NTRS)

Shull, Robert D.

1990-01-01

This experiment was originally designed and performed by Lord Kelvin (William Thomson) in the late 1800's to demonstrate the creation of an electric potential simply by means of dividing up a body of flowing water. The objective is to demonstrate the power of electrical forces in a material as common as water and to help teach the student that even simple, well understood phenomena sometimes present unexpected results that, at first thought, defeat explanation. The experimental equipment and procedure are explained.

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

Refrigerant leak detector

NASA Technical Reports Server (NTRS)

Byrne, E. J.

1979-01-01

Quantitative leak detector visually demonstrates refrigerant loss from precision volume of large refrigeration system over established period of time from single test point. Mechanical unit is less costly than electronic "sniffers" and is more reliable due to absence of electronic circuits that are susceptible to drift.

A Compact, High-Performance Continuous Magnetic Refrigerator

NASA Technical Reports Server (NTRS)

Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Jackson, Michael; King, Todd; Panek, John; Tuttle, James; Brodeur, Stephen J. (Technical Monitor)

2001-01-01

We present test results of the first adiabatic demagnetization refrigerator (ADR) that can produce continuous cooling at sub-kelvin temperatures. This system uses multiple stages that operate in sequence to cascade heat from a continuous stage up to a heat sink. Continuous operation aids the usual constraints of long hold times and short recycle times that lead to the generally large mass of single-shot ADRs, and allows us to achieve much higher cooling power per unit mass. Our design goal is 10 microW of cooling at 50 mK while rejecting heat to a 6-10 K heat sink. The total cold mass is estimated to be less than 10 kg, including magnetic shielding of each stage. These parameters envelop the requirements for currently planned astronomy missions. The relatively high heat rejection capability allows it to operate with a mechanical cryocooler as part of a cryogen-free, low temperature cooling system. This has the advantages of long, mission life and reduced complexity and cost. At present, we have assembled a three-stage ADR that operates with a superfluid helium bath. Additional work is underway to develop magnetocaloric materials that can extend its heat rejection capability up to 10 K. This paper discusses the design and operation of the ADR, as well as interface requirements for cryocooler-based operation.

Quantum-circuit refrigerator

NASA Astrophysics Data System (ADS)

Tan, Kuan Yen; Partanen, Matti; Lake, Russell E.; Govenius, Joonas; Masuda, Shumpei; Möttönen, Mikko

2017-05-01

Quantum technology promises revolutionizing applications in information processing, communications, sensing and modelling. However, efficient on-demand cooling of the functional quantum degrees of freedom remains challenging in many solid-state implementations, such as superconducting circuits. Here we demonstrate direct cooling of a superconducting resonator mode using voltage-controllable electron tunnelling in a nanoscale refrigerator. This result is revealed by a decreased electron temperature at a resonator-coupled probe resistor, even for an elevated electron temperature at the refrigerator. Our conclusions are verified by control experiments and by a good quantitative agreement between theory and experimental observations at various operation voltages and bath temperatures. In the future, we aim to remove spurious dissipation introduced by our refrigerator and to decrease the operational temperature. Such an ideal quantum-circuit refrigerator has potential applications in the initialization of quantum electric devices. In the superconducting quantum computer, for example, fast and accurate reset of the quantum memory is needed.

The free-energy barrier to hydride transfer across a dipalladium complex

DOE PAGES

Ramirez-Cuesta, Anibal J.

2015-01-01

We use density-functional theory molecular dynamics (DFT-MD) simulations to determine the hydride transfer coordinate between palladium centres of the crystallographically observed terminal hydride locations, Pd-Pd-H, originally postulated for the solution dynamics of the complex bis-NHC dipalladium hydride [{(MesIm)(2)CH2}(2)Pd2H][PF6], and then calculate the free-energy along this coordinate. We estimate the transfer barrier-height to be about 20 kcal mol(-1) with a hydride transfer rate in the order of seconds at room temperature. We validate our DFT-MD modelling using inelastic neutron scattering which reveals anharmonicity of the hydride environment that is so pronounced that there is complete failure of the harmonic model formore » the hydride ligand. The simulations are extended to high temperature to bring the H-transfer to a rate that is accessible to the simulation technique.« less

Characteristics of a Refrigeration Cycle Using a Zeotropic Refrigerant Mixture with a Temperature Glide Shift Heat Exchanger

NASA Astrophysics Data System (ADS)

Endoh, Kazuhiro; Matsushima, Hiroaki; Nonaka, Masayuki

HFC zeotropic refrigerant mixture R-407C is one of the promising alternatives for HCFC-22. We have found that the coefficient of performance (COP) of the refrigeration cycle using R-407C is improved by installing a temperature glide shift heat exchanger (TGSX) which takes advantage of zeotropic characteristics to an air-conditioner. We obtained the characteristics of a refrigeration cycle of experimental apparatus with comparison to those of a fundamental refrigeration cycle based on the refrigerant thermodynamic properties. We concluded that the COP improvement ratio of experimental apparatus with the TGSX to that without the TGSX is greater than that ratio which is calculated from the fundamental refrigeration cycle. This proved to be caused by the pressure loss of low pressure side which is not taken into account in the fundamental refrigeration cycle.

Thermoelectric refrigerator having improved temperature stabilization means

DOEpatents

Falco, Charles M.

1982-01-01

A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized.

Destabilisation of complex hydrides through size effects.

PubMed

Christian, Meganne; Aguey-Zinsou, Kondo-Francois

2010-12-01

Nanoparticles of NaAlH4, LiAlH4 and LiBH4 were prepared by encapsulating their respective hydrides within carbon nanotubes by a wet chemical approach. The resulting confinement had a profound effect on the overall hydrogen storage properties of these hydrides, with NaAlH4 and LiAlH4 releasing hydrogen from room temperature, for example.

Refrigerated cryogenic envelope

DOEpatents

Loudon, John D.

1976-11-16

An elongated cryogenic envelope including an outer tube and an inner tube coaxially spaced within said inner tube so that the space therebetween forms a vacuum chamber for holding a vacuum. The inner and outer tubes are provided with means for expanding or contracting during thermal changes. A shield is located in the vacuum chamber intermediate the inner and outer tubes; and, a refrigeration tube for directing refrigeration to the shield is coiled about at least a portion of the inner tube within the vacuum chamber to permit the refrigeration tube to expand or contract along its length during thermal changes within said vacuum chamber.

AIR PASSIVATION OF METAL HYDRIDE BEDS FOR WASTE DISPOSAL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, J; R. H. Hsu, R

2007-07-02

Metal hydride beds offer compact, safe storage of tritium. After metal hydride beds have reached the end of their useful life, the beds will replaced with new beds and the old beds prepared for disposal. One acceptance criteria for hydride bed waste disposal is that the material inside the bed not be pyrophoric. To determine the pyrophoric nature of spent metal hydride beds, controlled air ingress tests were performed. A simple gas handling manifold fitted with pressure transducers and a calibrated volume were used to introduce controlled quantities of air into a metal hydride bed and the bed temperature risemore » monitored for reactivity with the air. A desorbed, 4.4 kg titanium prototype hydride storage vessel (HSV) produced a 4.4 C internal temperature rise upon the first air exposure cycle and a 0.1 C temperature rise upon a second air exposure. A total of 346 scc air was consumed by the bed (0.08 scc per gram Ti). A desorbed, 9.66 kg LaNi{sub 4.25}Al{sub 0.75} prototype storage bed experienced larger temperature rises over successive cycles of air ingress and evacuation. The cycles were performed over a period of days with the bed effectively passivated after the 12th cycle. Nine to ten STP-L of air reacted with the bed producing both oxidized metal and water.« less

Hydrogen storage in the form of metal hydrides

NASA Technical Reports Server (NTRS)

Zwanziger, M. G.; Santana, C. C.; Santos, S. C.

1984-01-01

Reversible reactions between hydrogen and such materials as iron/titanium and magnesium/ nickel alloy may provide a means for storing hydrogen fuel. A demonstration model of an iron/titanium hydride storage bed is described. Hydrogen from the hydride storage bed powers a converted gasoline electric generator.

High energy density battery based on complex hydrides

DOEpatents

Zidan, Ragaiy

2016-04-26

A battery and process of operating a battery system is provided using high hydrogen capacity complex hydrides in an organic non-aqueous solvent that allows the transport of hydride ions such as AlH.sub.4.sup.- and metal ions during respective discharging and charging steps.

Hydrogen and dihydrogen bonding of transition metal hydrides

NASA Astrophysics Data System (ADS)

Jacobsen, Heiko

2008-04-01

Intermolecular interactions between a prototypical transition metal hydride WH(CO) 2NO(PH 3) 2 and a small proton donor H 2O have been studied using DFT methodology. The hydride, nitrosyl and carbonyl ligand have been considered as site of protonation. Further, DFT-D calculations in which empirical corrections for the dispersion energy are included, have been carried out. A variety of pure and hybrid density functionals (BP86, PW91, PBE, BLYP, OLYP, B3LYP, B1PW91, PBE0, X3LYP) have been considered, and our calculations indicate the PBE functional and its hybrid variation are well suited for the calculation of transition metal hydride hydrogen and dihydrogen bonding. Dispersive interactions make up for a sizeable portion of the intermolecular interaction, and amount to 20-30% of the bond energy and to 30-40% of the bond enthalpy. An energy decomposition analysis reveals that the H⋯H bond of transition metal hydrides contains both covalent and electrostatic contributions.

Direct condensation refrigerant recovery and restoration system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant, D.C.H.

1992-03-10

This patent describes a refrigerant recovery and purification system for removing gaseous refrigerant from a disabled refrigeration unit, cleaning the refrigerant of contaminants, and converting the gaseous refrigerant to a liquid state for storage. It comprises a low pressure inlet section; a high pressure storage section; the low pressure inlet section comprising: an oil and refrigerant gas separator, including a separated oil removal means, first conduit means for connecting an inlet of the separator to the disabled refrigerant unit, a slack-sided accumulator, second conduit means connecting the separator to the slack-sided accumulator, a reclaim condenser, third conduit means connecting themore » separator and the reclaim condenser in series, an evaporator coil in the reclaim condenser connectable to a conventional operating refrigeration system for receiving a liquid refrigerant under pressure for expansion therein, the evaporator coil forming a condensing surface for condensing the refrigerant gas at near atmospheric pressure in the condenser, a liquid receiver, a reclaimed refrigerant storage tank, fourth conduit means further connecting the liquid receiver in series with the reclaim condenser, downstream thereof, means between the reclaim condenser and the liquid receiver.« less

Regenerative Hydride Heat Pump

NASA Technical Reports Server (NTRS)

Jones, Jack A.

1992-01-01

Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

Kelvin Wave Influence on the Shallow-to-Deep Transition Over the Amazon

NASA Astrophysics Data System (ADS)

Rowe, A.; Serra, Y. L.

2017-12-01

The suite of observations from GOAmazon and CHUVA offers a unique opportunity to examine land-based convective processes in the tropics, including the poorly represented shallow-to-deep transition. This study uses these data to investigate impacts of Kelvin waves on the the shallow-to-deep transition over the Central Amazon. The Kelvin waves that propagate over the region often originate over the tropical central and east Pacific, with local generation over the Andes also observed. The observed 15 m s-1 phase speed and 4500 km wave length during the two-year campaign are in agreement with previously published studies of these waves across the tropics. Also in agreement with previous studies, we find the waves are most active during the wet season (November-May) for this region. Using four separate convective event classes (clear-sky, nonprecipitating cumulus congestus, afternoon deep convection, and mesoscale convective systems), we examine how the convection preferentially develops for different phases of the Kelvin waves seen during GOAmazon. We additionally examine surface meteorological variables, the vertical thermodynamic and dynamic structure of the troposphere, vertical moist static stability, integrated column water vapor and liquid water, and surface energy fluxes within the context of these convective classes to identify the important environmental factors contributing to observed periods of enhanced deep convection related to the waves. Results suggest that the waves significantly modify the local environment, such as creating a deep layer of moisture throughout the troposphere, favoring more organized convection in the active than in the suppressed phase of the wave. The significance of wave-related environmental modifications are assessed by comparing local rainfall accumulations during Kelvin wave activity to that when the waves are not present. Future work will further explore the shallow-to-deep transition and its modulation by Kelvin wave activity

On the Chemistry of Hydrides of N Atoms and O+ Ions

NASA Astrophysics Data System (ADS)

Awad, Zainab; Viti, Serena; Williams, David A.

2016-08-01

Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low-density lines of sight toward G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models. In this paper we investigate the role of surface reactions on dust grains in diffuse regions, and we find that formation of the hydrides by surface reactions on dust grains with efficiency comparable to that for H2 formation reconciles models with observations of nitrogen hydrides. However, similar surface reactions do not contribute significantly to the hydrides of O+ ions detected by Herschel/HIFI that are present along many sight lines in the Galaxy. The O+ hydrides can be accounted for by conventional gas-phase chemistry either in diffuse clouds of very low density with normal cosmic-ray fluxes or in somewhat denser diffuse clouds with high cosmic-ray fluxes. Hydride chemistry in dense dark clouds appears to be dominated by gas-phase ion-molecule reactions.

Modeling and development of a superfluid magnetic pump with no moving parts

NASA Astrophysics Data System (ADS)

Jahromi, Amir Eshraghniaye; Miller, Franklin; Nellis, Gregory

2012-06-01

Current state of the art sub Kelvin Superfluid Stirling Refrigerators and Pulse tube Superfluid Refrigerators use multiple bellows pistons to execute the cycle. These types of displacers can be replaced by a newly introduced pump, a Superfluid Magnetic Pump, with no moving parts. Integration of this pump in the Pulse tube Superfluid Refrigeration system will make it a sub Kelvin Stirling refrigeration system free of any moving parts that is suitable for use in space cooling applications. The Superfluid Magnetic Pump consists of a canister that contains Gadolinium Gallium Garnet particles that is surrounded by a superconducting magnetic coil. The driving mechanism of this pump is the fountain effect in He II. A qualitative description of one cycle operation of the Superfluid Magnetic Pump is presented followed by a numerical model for each process of the cycle.

Low-valent group 14 element hydride chemistry: towards catalysis.

PubMed

Hadlington, Terrance J; Driess, Matthias; Jones, Cameron

2018-06-05

The chemistry of group 14 element(ii) hydride complexes has rapidly expanded since the first stable example of such a compound was reported in 2000. Since that time it has become apparent that these systems display remarkable reactivity patterns, in some cases mimicking those of late transition-metal (TM) hydride compounds. This is especially so for the hydroelementation of unsaturated organic substrates. Recently, this aspect of their reactivity has been extended to the use of group 14 element(ii) hydrides as efficient, "TM-like" catalysts in organic synthesis. This review will detail how the chemistry of these hydride compounds has advanced since their early development. Throughout, there is a focus on the importance of ligand effects in these systems, and how ligand design can greatly modify a coordinated complex's electronic structure, reactivity, and catalytic efficiency.

Transition to New Refrigerants

EPA Pesticide Factsheets

Overview page provides information on the refrigerants that motor vehicle air conditioners have used over time, with information on environmental impacts, refrigerant fitting sizes, label colors, and alternatives to ozone-depleting substances.

Status Of Sorption Cryogenic Refrigeration

NASA Technical Reports Server (NTRS)

Jones, Jack A.

1988-01-01

Report reviews sorption refrigeration. Developed for cooling infrared detectors, cryogenic research, and other advanced applications, sorption refrigerators have few moving parts, little vibration, and lifetimes of 10 years or more. Describes types of sorption stages, multistage and hybrid refrigeration systems, power requirements, cooling capacities, and advantages and disadvantages of various stages and systems.

Noise performance of frequency modulation Kelvin force microscopy

PubMed Central

Deresmes, Dominique; Mélin, Thierry

2014-01-01

Summary Noise performance of a phase-locked loop (PLL) based frequency modulation Kelvin force microscope (FM-KFM) is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as “noise gain” from operational amplifier (OpAmp) design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values. PMID:24455457

Influence of QBO on stratospheric Kelvin and Mixed Rossby gravity waves in high-top CMIP5 models

NASA Astrophysics Data System (ADS)

Indah Solihah, Karina; Lubis, Sandro W.; Setiawan, Sonni

2018-05-01

It is well established that quasi-biennial oscillation (QBO) has a substantial influence on Kelvin and mixed Rossby gravity (MRG) wave activity in the tropical lower stratosphere. In this study, we examined how QBO influences Kelvin and MRG wave activity in the lower stratosphere, based on nine high-top CMIP5 models. The results show that the Kelvin and MRG wave signals are stronger in the models with QBO, and relatively weaker in the models without QBO. The results are consistent with established theory, whereby upward-propagating Kelvin waves occurs more frequently during the easterly QBO phase, while upward-propagating MRG waves occurs during the westerly QBO phase. Without the QBO, the mean flow exhibits a near-zero easterly wind, which prevents the waves from propagating and penetrating into the stratosphere. Our analysis also shows that models with the QBO tend to have more robust signatures (in terms of amplitude and phase speed) of Kelvin and MRG waves.

Refrigeration system oil measurement and sampling device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, J.A.

1989-09-19

This patent describes a sampling device for use with a refrigeration system having a refrigerant and oil entrained therein. It comprises: an elongated reservoir having a stepped bore therein for receiving refrigerant and oil carried thereby. The reservoir comprising a large bore diameter upper section having an index marking the fill level of the reservoir and a small bore diameter lower section having graduation marks for oil level measurement. The upper and lower sections comprising transparent material to allow observation of the contents, first valve means for coupling the reservoir to the refrigeration system to admit liquid refrigerant to themore » reservoir, second valve means for selectively coupling the reservoir to the low pressure side of the refrigeration system or to a vacuum line to evacuate vaporized refrigerant from the reservoir, and means for supplying heat to the refrigerant in the bore to facilitate vaporization of the refrigerant.« less

Refrigeration for Cryogenic Sensors

NASA Technical Reports Server (NTRS)

Gasser, M. G. (Editor)

1983-01-01

Research in cryogenically cooled refrigerators is discussed. Low-power Stirling cryocoolers; spacecraft-borne long-life units; heat exchangers; performance tests; split-stirling, linear-resonant, cryogenic refrigerators; and computer models are among the topics discussed.

Variability of Kelvin wave momentum flux from high-resolution radiosonde and radio occultation data

NASA Astrophysics Data System (ADS)

Sjoberg, J. P.; Zeng, Z.; Ho, S. P.; Birner, T.; Anthes, R. A.; Johnson, R. H.

2017-12-01

Direct measurement of momentum flux from Kelvin waves in the stratosphere remains challenging. Constraining this flux from observations is an important step towards constraining the flux from models. Here we present results from analyses using linear theory to estimate the Kelvin wave amplitudes and momentum fluxes from both high-resolution radiosondes and from radio occultation (RO) data. These radiosonde data are from a contiguous 11-year span of soundings performed at two Department of Energy Atmospheric Radiation Measurement sites, while the RO data span 14 years from multiple satellite missions. Daily time series of the flux from both sources are found to be in quantitative agreement with previous studies. Climatological analyses of these data reveal the expected seasonal cycle and variability associated with the quasi-biennial oscillation. Though both data sets provide measurements on distinct spatial and temporal scales, the estimated flux from each provides insight into separate but complimentary aspects of how the Kelvin waves affect the stratosphere. Namely, flux derived from radiosonde sites provide details on the regional Kelvin wave variability, while the flux from RO data are zonal mean estimates.

Effect of hydrogenation conditions on the microstructure and mechanical properties of zirconium hydride

NASA Astrophysics Data System (ADS)

Muta, Hiroaki; Nishikane, Ryoji; Ando, Yusuke; Matsunaga, Junji; Sakamoto, Kan; Harjo, Stefanus; Kawasaki, Takuro; Ohishi, Yuji; Kurosaki, Ken; Yamanaka, Shinsuke

2018-03-01

Precipitation of brittle zirconium hydrides deteriorate the fracture toughness of the fuel cladding tubes of light water reactor. Although the hydride embrittlement has been studied extensively, little is known about physical properties of the hydride due to the experimental difficulties. In the present study, to elucidate relationship between mechanical properties and microstructure, two δ-phase zirconium hydrides and one ε-phase zirconium hydride were carefully fabricated considering volume changes at the metal-to-hydride transformation. The δ-hydride that was fabricated from α-zirconium exhibits numerous inner cracks due to the large volume change. Analyses of the neutron diffraction pattern and electron backscatter diffraction (EBSD) data show that the sample displays significant stacking faults in the {111} plane and in the pseudo-layered microstructure. On the other hand, the δ-hydride sample fabricated from β-zirconium at a higher temperature displays equiaxed grains and no cracks. The strong crystal orientation dependence of mechanical properties were confirmed by indentation test and EBSD observation. The δ-hydride hydrogenated from α-zirconium displays a lower Young's modulus than that prepared from β-zirconium. The difference is attributed to stacking faults within the {111} plane, for which the Young's modulus exhibits the highest value in the perpendicular direction. The strong influence of the crystal orientation and dislocation density on the mechanical properties should be considered when evaluating hydride precipitates in nuclear fuel cladding.

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Code of Federal Regulations, 2011 CFR

2011-01-01

...-section. Basic model means, with respect to commercial refrigerators, freezers, and refrigerator-freezers... 430); (2) Is not designed and marketed exclusively for medical, scientific, or research purposes; (3... standard product temperature-measuring device. Vertical Closed means equipment with hinged or sliding doors...

Influence of the nozzle angle on refrigeration performance of a gas wave refrigerator

NASA Astrophysics Data System (ADS)

Liu, P.; Zhu, Y.; Wang, H.; Zhu, C.; Zou, J.; Wu, J.; Hu, D.

2017-05-01

A gas wave refrigerator (GWR) is a novel refrigerating device that refrigerates a medium by shock waves and expansion waves generated by gas pressure energy. In a typical GWR, the injection energy losses between the nozzle and the expansion tube are essential factors which influence the refrigeration efficiency. In this study, numerical simulations are used to analyze the underlying mechanism of the injection energy losses. The results of simulations show that the vortex loss, mixing energy loss, and oblique shock wave reflection loss are the main factors contributing to the injection energy losses in the expansion tube. Furthermore, the jet angle of the gas is found to dominate the injection energy losses. Therefore, the optimum jet angle is theoretically calculated based on the velocity triangle method. The value of the optimum jet angle is found to be 4^{circ }, 8^{circ }, and 12^{circ } when the refrigeration efficiency is the first-order, second-order, and third-order maximum value over all working ranges of jet frequency, respectively. Finally, a series of experiments are conducted with the jet angle ranging from -4^{circ } to 12^{circ } at a constant expansion ratio. The results indicate the optimal jet angle obtained by the experiments is in good agreement with the calculated value. The isentropic refrigeration efficiency increased by about 4 % after the jet angle was optimized.

Influence of uranium hydride oxidation on uranium metal behaviour

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, N.; Hambley, D.; Clarke, S.A.

2013-07-01

This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, ifmore » sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)« less

Refrigeration generation using expander-generator units

NASA Astrophysics Data System (ADS)

Klimenko, A. V.; Agababov, V. S.; Koryagin, A. V.; Baidakova, Yu. O.

2016-05-01

The problems of using the expander-generator unit (EGU) to generate refrigeration, along with electricity were considered. It is shown that, on the level of the temperatures of refrigeration flows using the EGU, one can provide the refrigeration supply of the different consumers: ventilation and air conditioning plants and industrial refrigerators and freezers. The analysis of influence of process parameters on the cooling power of the EGU, which depends on the parameters of the gas expansion process in the expander and temperatures of cooled environment, was carried out. The schematic diagram of refrigeration generation plant based on EGU is presented. The features and advantages of EGU to generate refrigeration compared with thermotransformer of steam compressive and absorption types were shown, namely: there is no need to use the energy generated by burning fuel to operate the EGU; beneficial use of the heat delivered to gas from the flow being cooled in equipment operating on gas; energy production along with refrigeration generation, which makes it possible to create, using EGU, the trigeneration plants without using the energy power equipment. It is shown that the level of the temperatures of refrigeration flows, which can be obtained by using the EGU on existing technological decompression stations of the transported gas, allows providing the refrigeration supply of various consumers. The information that the refrigeration capacity of an expander-generator unit not only depends on the parameters of the process of expansion of gas flowing in the expander (flow rate, temperatures and pressures at the inlet and outlet) but it is also determined by the temperature needed for a consumer and the initial temperature of the flow of the refrigeration-carrier being cooled. The conclusion was made that the expander-generator units can be used to create trigeneration plants both at major power plants and at small energy.

Low-Cost Metal Hydride Thermal Energy Storage System for Concentrating Solar Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zidan, Ragaiy; Hardy, B. J.; Corgnale, C.

2016-01-31

The objective of this research was to evaluate and demonstrate a metal hydride-based TES system for use with a CSP system. A unique approach has been applied to this project that combines our modeling experience with the extensive material knowledge and expertise at both SRNL and Curtin University (CU). Because of their high energy capacity and reasonable kinetics many metal hydride systems can be charged rapidly. Metal hydrides for vehicle applications have demonstrated charging rates in minutes and tens of minutes as opposed to hours. This coupled with high heat of reaction allows metal hydride TES systems to produce verymore » high thermal power rates (approx. 1kW per 6-8 kg of material). A major objective of this work is to evaluate some of the new metal hydride materials that have recently become available. A problem with metal hydride TES systems in the past has been selecting a suitable high capacity low temperature metal hydride material to pair with the high temperature material. A unique aspect of metal hydride TES systems is that many of these systems can be located on or near dish/engine collectors due to their high thermal capacity and small size. The primary objective of this work is to develop a high enthalpy metal hydride that is capable of reversibly storing hydrogen at high temperatures (> 650 °C) and that can be paired with a suitable low enthalpy metal hydride with low cost materials. Furthermore, a demonstration of hydrogen cycling between the two hydride beds is desired.« less

THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS

EPA Science Inventory

Hydrofluorocarbon (HFC) refrigerants are possible alternatives to replace ozone-depleting chlorofluorocarbon and hydrochlorofluorocarbon (HCFC) refrigerants. The flammability of a proposed new refrigerant is a major consideration in assessing its utility for a particular applicat...

Precipitation of hydrides in high purity niobium after different treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barkov, F.; Romanenko, A.; Trenikhina, Y.

Precipitation of lossy non-superconducting niobium hydrides represents a known problem for high purity niobium in superconducting applications. Using cryogenic optical and laser confocal scanning microscopy we have directly observed surface precipitation and evolution of niobium hydrides in samples after different treatments used for superconducting RF cavities for particle acceleration. Precipitation is shown to occur throughout the sample volume, and the growth of hydrides is well described by the fast diffusion-controlled process in which almost all hydrogen is precipitated atmore » $T=140$~K within $$\\sim30$$~min. 120$$^{\\circ}$$C baking and mechanical deformation are found to affect hydride precipitation through their influence on the number of nucleation and trapping centers.« less

Neutron diffraction investigation of γ manganese hydride

NASA Astrophysics Data System (ADS)

Fedotov, V. K.; Antonov, V. E.; Kolesnikov, A. I.; Beskrovnyi, A. I.; Grosse, G.; Wagner, F. E.

1998-08-01

A profile analysis of the neutron diffraction spectrum of the fcc high pressure hydride λ-MnH 0.41 measured under ambient conditions showed that hydrogen is randomly distributed over the octahedral interstices of the fcc metal lattice and that the hydride is an antiferromagnet with the same collinear spin structure as pure λ-Mn, but with a smaller magnetic moment of about 1.9 Bohr magnetons per Mn atom.

Potential emission savings from refrigeration and air conditioning systems by using low GWP refrigerants

DOE PAGES

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar; ...

2016-08-24

Refrigeration and air conditioning systems have high, negative environmental impacts due to refrigerant charge leaks from the system and their corresponding high global warming potential. Thus, many efforts are in progress to obtain suitable low GWP alternative refrigerants and more environmentally friendly systems for the future. In addition, the system’s life cycle climate performance (LCCP) is a widespread metric proposed for the evaluation of the system’s environmental impact.

Potential emission savings from refrigeration and air conditioning systems by using low GWP refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar

Refrigeration and air conditioning systems have high, negative environmental impacts due to refrigerant charge leaks from the system and their corresponding high global warming potential. Thus, many efforts are in progress to obtain suitable low GWP alternative refrigerants and more environmentally friendly systems for the future. In addition, the system’s life cycle climate performance (LCCP) is a widespread metric proposed for the evaluation of the system’s environmental impact.

Design of refrigeration system using refrigerant R134a for macro compartment

NASA Astrophysics Data System (ADS)

Rani, M. F. H.; Razlan, Z. M.; Shahriman, A. B.; Yong, C. K.; Harun, A.; Hashim, M. S. M.; Faizi, M. K.; Ibrahim, I.; Kamarrudin, N. S.; Saad, M. A. M.; Zunaidi, I.; Wan, W. K.; Desa, H.

2017-10-01

The main objective of this study is to analyse and design an optimum cooling system for macro compartment. Current product of the refrigerator is not specified for single function and not compact in size. Hence, a refrigeration system using refrigerant R134a is aimed to provide instant cooling in a macro compartment with sizing about 150 × 150 × 250 mm. The macro compartment is purposely designed to fit a bottle or drink can, which is then cooled to a desired drinking temperature of about 8°C within a period of 1 minute. The study is not only concerned with analysing of heat load of the macro compartment containing drink can, but also focused on determining suitable heat exchanger volume for both evaporator and condenser, calculating compressor displacement value and computing suitable resistance value of the expansion valve. Method of optimization is used to obtain the best solution of the problem. Mollier diagram is necessary in the process of developing the refrigeration system. Selection of blower is made properly to allow air circulation and to increase the flow rate for higher heat transfer rate. Property data are taken precisely from thermodynamic property tables. As the main four components, namely condenser, compressor, evaporator and expansion valve are fully developed, the refrigeration system is complete.

A nickel metal hydride battery for electric vehicles

NASA Astrophysics Data System (ADS)

Ovshinsky, S. R.; Fetcenko, M. A.; Ross, J.

1993-04-01

An efficient battery is the key technological element to the development of practical electric vehicles. The science and technology of a nickel metal hydride battery, which stores hydrogen in the solid hydride phase and has high energy density, high power, long life, tolerance to abuse, a wide range of operating temperature, quick-charge capability, and totally sealed maintenance-free operation, is described. A broad range of multi-element metal hydride materials that use structural and compositional disorder on several scales of length has been engineered for use as the negative electrode in this battery. The battery operates at ambient temperature, is made of nontoxic materials, and is recyclable. Demonstration of the manufacturing technology has been achieved.

Method and apparatus for desuperheating refrigerant

DOEpatents

Zess, James A.; Drost, M. Kevin; Call, Charles J.

1997-01-01

The present invention is an apparatus and method for de-superheating a primary refrigerant leaving a compressor wherein a secondary refrigerant is used between the primary refrigerant to be de-superheated. Reject heat is advantageously used for heat reclaim.

Performance modeling of optical refrigerators

NASA Astrophysics Data System (ADS)

Mills, Gary; Mord, Allan

2006-02-01

Optical refrigeration using anti-Stokes fluorescence in solids has several advantages over more conventional techniques including low mass, low volume, low cost and no vibration. It also has the potential of allowing miniature cryocoolers on the scale of a few cubic centimeters. It has been the topic of analysis and experimental work by several organizations. In 2003, we demonstrated the first optical refrigerator. We have developed a comprehensive system-level performance model of optical refrigerators. Our current version models the refrigeration cycle based on the fluorescent material emission and absorption data at ambient and reduced temperature for the Ytterbium-ZBLAN glass (Yb:ZBLAN) cooling material. It also includes the heat transfer into the refrigerator cooling assembly due to radiation and conduction. In this paper, we report on modeling results which reveal the interplay between size, power input, and cooling load. This interplay results in practical size limitations using Yb:ZBLAN.

Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tummala, Hareesh; Capolungo, Laurent; Tome, Carlos N.

This report is a preliminary study on δ-hydride precipitate in zirconium alloy performed using 3D discrete dislocation dynamics simulations. The ability of dislocations in modifying the largely anisotropic stress fields developed by the hydride particle in a matrix phase is addressed for a specific dimension of the hydride. The influential role of probable dislocation nucleation at the hydride-matrix interface is reported. Dislocation nucleation around a hydride was found to decrease the shear stress (S 13) and also increase the normal stresses inside the hydride. We derive conclusions on the formation of stacks of hydrides in zirconium alloys. The contribution ofmore » mechanical fields due to dislocations was found to have a non-negligible effect on such process.« less

Refrigeration system having dual suction port compressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Guolian

A cooling system for appliances, air conditioners, and other spaces includes a compressor, and a condenser that receives refrigerant from the compressor. The system also includes an evaporator that receives refrigerant from the condenser. Refrigerant received from the condenser flows through an upstream portion of the evaporator. A first portion of the refrigerant flows to the compressor without passing through a downstream portion of the evaporator, and a second portion of the refrigerant from the upstream portion of the condenser flows through the downstream portion of the evaporator after passing through the upstream portion of the evaporator. The second portionmore » of the refrigerant flows to the compressor after passing through the downstream portion of the evaporator. The refrigeration system may be configured to cool an appliance such as a refrigerator and/or freezer, or it may be utilized in air conditioners for buildings, motor vehicles, or other such spaces.« less

Performance of the Three-Stage ADR that Provides Cooling of the Soft X-Ray Spectrometer Aboard Astro-H

NASA Technical Reports Server (NTRS)

Kimball, Mark 0.; Shirron, Peter J.

2011-01-01

The requirements levied upon the cooling system for the soft X-ray spectrometer (SXS) aboard the Astro-H satellite are demanding: Provide an operating temperature of 0.050 degrees Kelvin for a minimum of 24 hours, recycle in less than 2 hours (less than 1 hour in some cases), produce a dipole moment of less than 10 amperes per square meter at the detector location, and do all this with a mass less than 15 kilograms. This is further complicated by the availability of both a 1.3 degrees Kelvin helium bath and a 4.5 degrees Kelvin JT (Joule-Thomson) cooler to recycle the refrigerator. Here we detail the performance of the adiabatic demagnetization refrigerator (ADR) built specifically for SXS that is capable of meeting, and often significantly exceeding, the requirements placed upon it.

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

An elasto-plastic fracture mechanics based model for assessment of hydride embrittlement in zircaloy cladding tubes

NASA Astrophysics Data System (ADS)

Nilsson, Karl-Fredrik; Jakšić, Nikola; Vokál, Vratko

2010-01-01

This paper describes a finite element based fracture mechanics model to assess how hydrides affect the integrity of zircaloy cladding tubes. The hydrides are assumed to fracture at a low load whereas the propagation of the fractured hydrides in the matrix material and failure of the tube is controlled by non-linear fracture mechanics and plastic collapse of the ligaments between the hydrides. The paper quantifies the relative importance of hydride geometrical parameters such as size, orientation and location of individual hydrides and interaction between adjacent hydrides. The paper also presents analyses for some different and representative multi-hydride configurations. The model is adaptable to general and complex crack configurations and can therefore be used to assess realistic hydride configurations. The mechanism of cladding failure is by plastic collapse of ligaments between interacting fractured hydrides. The results show that the integrity can be drastically reduced when several radial hydrides form continuous patterns.

A comparative study on the environmental impact of supermarket refrigeration systems using low GWP refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beshr, M.; Aute, V.; Sharma, V.

Supermarket refrigeration systems have high environmental impact due to their large refrigerant charge and high leak rates. Consequently, the interest in using low GWP refrigerants such as carbon dioxide (CO 2) and new refrigerant blends is increasing. In this study, an open-source Life Cycle Climate Performance (LCCP) framework is presented and used to compare the environmental impact of four supermarket refrigeration systems: a transcritical CO 2 booster system, a cascade CO 2/N-40 system, a combined secondary circuit with central DX N-40/L-40 system, and a baseline multiplex direct expansion system utilizing R-404A and N-40. The study is performed for different climatesmore » within the USA using EnergyPlus to simulate the systems' hourly performance. Finally, further analyses are presented such as parametric, sensitivity, and uncertainty analyses to study the impact of different system parameters on the LCCP.« less

A comparative study on the environmental impact of supermarket refrigeration systems using low GWP refrigerants

DOE PAGES

Beshr, M.; Aute, V.; Sharma, V.; ...

2015-04-09

Supermarket refrigeration systems have high environmental impact due to their large refrigerant charge and high leak rates. Consequently, the interest in using low GWP refrigerants such as carbon dioxide (CO 2) and new refrigerant blends is increasing. In this study, an open-source Life Cycle Climate Performance (LCCP) framework is presented and used to compare the environmental impact of four supermarket refrigeration systems: a transcritical CO 2 booster system, a cascade CO 2/N-40 system, a combined secondary circuit with central DX N-40/L-40 system, and a baseline multiplex direct expansion system utilizing R-404A and N-40. The study is performed for different climatesmore » within the USA using EnergyPlus to simulate the systems' hourly performance. Finally, further analyses are presented such as parametric, sensitivity, and uncertainty analyses to study the impact of different system parameters on the LCCP.« less

Heat Switches Providing Low-Activation Power and Quick-Switching Time for Use in Adiabatic Demagnetization Refrigerators

NASA Technical Reports Server (NTRS)

Kimball, Mark O.; Shirron, Peter J.

2011-01-01

An adiabatic demagnetization refrigerator (ADR) is a solid-state cooler capable of achieving sub-Kelvin temperatures. It neither requires moving parts nor a density gradient in a working fluid making it ideal for use in space-based instruments. The flow of energy through the cooler is controlled by heat switches that allow heat transfer when on and isolate portions of the cooler when off. One type of switch uses helium gas as the switching medium. In the off state the gas is adsorbed in a getter thus breaking the thermal path through the switch. To activate the switch, the getter is heated to release helium into the switch body allowing it to complete the thermal path. A getter that has a small heat capacity and low thermal conductance to the body of the switch requires low-activation power. The cooler benefits from this in two ways: shorter recycle times and higher efficiency. We describe such a design here.

Observations of Convectively Coupled Kelvin Waves forced by Extratropical Wave Activity

NASA Astrophysics Data System (ADS)

Kiladis, G. N.; Biello, J. A.; Straub, K. H.

2012-12-01

It is well established by observations that deep tropical convection can in certain situations be forced by extratropical Rossby wave activity. Such interactions are a well-known feature of regions of upper level westerly flow, and in particular where westerlies and equatorward wave guiding by the basic state occur at low enough latitudes to interact with tropical and subtropical moisture sources. In these regions convection is commonly initiated ahead of upper level troughs, characteristic of forcing by quasi-geostrophic dynamics. However, recent observational evidence indicates that extratropical wave activity is also associated with equatorial convection even in regions where there is a "critical line" to Rossby wave propagation at upper levels, that is, where the zonal phase speed of the wave is equal to the zonal flow speed. A common manifestation of this type of interaction involves the initiation of convectively coupled Kelvin waves, as well as mixed Rossby-gravity (MRG) waves. These waves are responsible for a large portion of the convective variability within the ITCZ over the Indian, Pacific, and Atlantic sectors, as well as within the Amazon Basin of South America. For example, Kelvin waves originating within the western Pacific ITCZ are often triggered by Rossby wave activity propagating into the Australasian region from the South Indian Ocean extratropics. At other times, Kelvin waves are seen to originate along the eastern slope of the Andes. In the latter case the initial forcing is sometimes linked to a low-level "pressure surge," initiated by wave activity propagating equatorward from the South Pacific storm track. In yet other cases, such as over Africa, the forcing appears to be related to wave activity in the extratropics which is not necessarily propagating into low latitudes, but appears to "project" onto the Kelvin structure, in line with past theoretical and modeling studies. Observational evidence for extratropical forcing of Kelvin and MRG

Electrochemical hydride generation for the simultaneous determination of hydride forming elements by inductively coupled plasma-atomic emission spectrometry

NASA Astrophysics Data System (ADS)

Bolea, E.; Laborda, F.; Castillo, J. R.; Sturgeon, R. E.

2004-04-01

Simultaneous measurements of As, Sb, Se, Sn and Ge were performed by inductively coupled plasma atomic emission spectrometry following their electrochemical hydride generation. An electrochemical hydride generator based on a concentric arrangement with a porous cathode, working in a continuous flow mode was used. The effects of sample flow rate, applied current and electrolytic solution concentration on response were studied and their influence on the mechanisms of hydride generation discussed. Four materials, particulate lead, reticulated vitreous carbon (RVC), silver and amalgamated silver were tested as cathode materials. The best results were achieved with particulate lead and RVC cathodes, wherein generation efficiencies higher than 80% were estimated for most of the analytes. In general, limits of detection between 0.1 and 3.6 ng ml -1 and a precision better than 5% were achieved using a lead cathode. The analysis of a marine sediment reference material (PACS-2, NRC) showed good agreement with the certified values for As and Se.

Development of Low Global Warming Potential Refrigerant Solutions for Commercial Refrigeration Systems using a Life Cycle Climate Performance Design Tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Fricke, Brian A; Vineyard, Edward Allan

Commercial refrigeration systems are known to be prone to high leak rates and to consume large amounts of electricity. As such, direct emissions related to refrigerant leakage and indirect emissions resulting from primary energy consumption contribute greatly to their Life Cycle Climate Performance (LCCP). In this paper, an LCCP design tool is used to evaluate the performance of a typical commercial refrigeration system with alternative refrigerants and minor system modifications to provide lower Global Warming Potential (GWP) refrigerant solutions with improved LCCP compared to baseline systems. The LCCP design tool accounts for system performance, ambient temperature, and system load; systemmore » performance is evaluated using a validated vapor compression system simulation tool while ambient temperature and system load are devised from a widely used building energy modeling tool (EnergyPlus). The LCCP design tool also accounts for the change in hourly electricity emission rate to yield an accurate prediction of indirect emissions. The analysis shows that conventional commercial refrigeration system life cycle emissions are largely due to direct emissions associated with refrigerant leaks and that system efficiency plays a smaller role in the LCCP. However, as a transition occurs to low GWP refrigerants, the indirect emissions become more relevant. Low GWP refrigerants may not be suitable for drop-in replacements in conventional commercial refrigeration systems; however some mixtures may be introduced as transitional drop-in replacements. These transitional refrigerants have a significantly lower GWP than baseline refrigerants and as such, improved LCCP. The paper concludes with a brief discussion on the tradeoffs between refrigerant GWP, efficiency and capacity.« less

46 CFR 154.702 - Refrigerated carriage.

Code of Federal Regulations, 2013 CFR

2013-10-01

... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage. (a) Each refrigeration system must: (1... the purpose of this section, a “refrigeration unit” includes a compressor and its motors and controls...

46 CFR 154.702 - Refrigerated carriage.

Code of Federal Regulations, 2012 CFR

2012-10-01

... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage. (a) Each refrigeration system must: (1... the purpose of this section, a “refrigeration unit” includes a compressor and its motors and controls...

46 CFR 154.702 - Refrigerated carriage.

Code of Federal Regulations, 2011 CFR

2011-10-01

... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage. (a) Each refrigeration system must: (1... the purpose of this section, a “refrigeration unit” includes a compressor and its motors and controls...

46 CFR 154.702 - Refrigerated carriage.

Code of Federal Regulations, 2010 CFR

2010-10-01

... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage. (a) Each refrigeration system must: (1... the purpose of this section, a “refrigeration unit” includes a compressor and its motors and controls...

46 CFR 154.702 - Refrigerated carriage.

Code of Federal Regulations, 2014 CFR

2014-10-01

... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage. (a) Each refrigeration system must: (1... the purpose of this section, a “refrigeration unit” includes a compressor and its motors and controls...

A historical look at chlorofluorocarbon refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatti, M.S.

1999-07-01

A class of chemical compounds called chlorofluorocarbon refrigerants has been in widespread use since the 1930s in such diverse applications as refrigerants for refrigerating and air-conditioning systems, blowing agents for plastic foams, solvents for microelectronic circuitry and dry cleaning, sterilants for medical instruments, aerosol propellants for personal hygiene products and pesticides, and freezants for food. This paper describes the historical development of the chlorofluorocarbon refrigerants and gives brief biographical sketches of the inventors. 85 refs., 8 figs., 4 tabs.

SIMULATION RESULTS OF SINGLE REFRIGERANTS FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER

EPA Science Inventory

The paper reviews the refrigerant/freezer (RF) design and refrigerant selection process that is necessary to design an energy efficient RF that does not use fully halogenated chlorofluorocarbons (CFCs). EPA is interested in phasing out CFCs in RFs to minimize stratospheric ozone ...

Control system for thermoelectric refrigerator

NASA Technical Reports Server (NTRS)

Nelson, John L. (Inventor); Criscuolo, Lance (Inventor); Gilley, Michael D. (Inventor); Park, Brian V. (Inventor)

1996-01-01

Apparatus including a power supply (202) and control system is provided for maintaining the temperature within an enclosed structure (40) using thermoelectric devices (92). The apparatus may be particularly beneficial for use with a refrigerator (20) having superinsulation materials (46) and phase change materials (112) which cooperate with the thermoelectric device (92) to substantially enhance the overall operating efficiency of the refrigerator (20). The electrical power supply (202) and control system allows increasing the maximum power capability of the thermoelectric device (92) in response to increased heat loads within the refrigerator (20). The electrical power supply (202) and control system may also be used to monitor the performance of the cooling system (70) associated with the refrigerator (20).

ecoSPEARS License Signing with Kelvin Manning

NASA Image and Video Library

2017-12-19

NASA Kennedy Space Center's Associate Director Kelvin Manning, center, signs a license agreement with the President and CEO of ecoSPEARS, which allows the company to commercially sell a soil remediation technology developed by a research team at Kennedy. The technology, known as Sorbent Polymer Extraction And Remediation System, is designed to capture and remove polychlorinated biphenyls (PCBs) from contaminated sediments in waterways and wetlands.

Comprehensive Compressor Calorimeter Testing of Lower-GWP Alternative Refrigerants for Heat Pump and Medium Temperature Refrigeration Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shrestha, Som S; Sharma, Vishaldeep; Abdelaziz, Omar

In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. This paper reports one of the Oak Ridge National Laboratory (ORNL) contributions to AREP. It compares performance of alternative refrigerants to that of R-410A and R-404A for heat pump and medium temperature applications, respectively. The alternatives reported in this paper are: R-32, DR-5, and L-41a for R-410A andmore » ARM-31a, D2Y-65, L-40, and a mixture of R-32 and R-134a for R-404A. All performance comparison tests were conducted using scroll compressors of ~1.85 tons (6.5 kW) cooling capacity. Tests were conducted over a range of combinations of saturation suction and saturation discharge temperatures for both compressors. The tests showed that, in general, energy efficiency ratio (EER) and cooling capacity of R-410A alternative refrigerants were slightly lower than that of the baseline refrigerant with a moderate increases in discharge temperature. On the other hand, R-404A alternative refrigerants showed relative performance dependence on saturation suction and saturation discharge temperatures and larger increases in discharge temperature than for the R-410A alternatives. This paper summarizes the relative performance of all alternative refrigerants compared to their respective baseline.« less

Dual-circuit, multiple-effect refrigeration system and method

DOEpatents

DeVault, Robert C.

1995-01-01

A dual circuit absorption refrigeration system comprising a high temperature single-effect refrigeration loop and a lower temperature double-effect refrigeration loop separate from one another and provided with a double-condenser coupling therebetween. The high temperature condenser of the single-effect refrigeration loop is double coupled to both of the generators in the double-effect refrigeration loop to improve internal heat recovery and a heat and mass transfer additive such as 2-ethyl-1-hexanol is used in the lower temperature double-effect refrigeration loop to improve the performance of the absorber in the double-effect refrigeration loop.

High-Performance, Low Environmental Impact Refrigerants

NASA Technical Reports Server (NTRS)

McCullough, E. T.; Dhooge, P. M.; Glass, S. M.; Nimitz, J. S.

2001-01-01

Refrigerants used in process and facilities systems in the US include R-12, R-22, R-123, R-134a, R-404A, R-410A, R-500, and R-502. All but R-134a, R-404A, and R-410A contain ozone-depleting substances that will be phased out under the Montreal Protocol. Some of the substitutes do not perform as well as the refrigerants they are replacing, require new equipment, and have relatively high global warming potentials (GWPs). New refrigerants are needed that addresses environmental, safety, and performance issues simultaneously. In efforts sponsored by Ikon Corporation, NASA Kennedy Space Center (KSC), and the US Environmental Protection Agency (EPA), ETEC has developed and tested a new class of refrigerants, the Ikon (registered) refrigerants, based on iodofluorocarbons (IFCs). These refrigerants are nonflammable, have essentially zero ozone-depletion potential (ODP), low GWP, high performance (energy efficiency and capacity), and can be dropped into much existing equipment.

Magnetic refrigeration for low-temperature applications

NASA Technical Reports Server (NTRS)

Barclay, J. A.

1985-01-01

The application of refrigeration at low temperatures ranging from production of liquid helium for medical imaging systems to cooling of infrared sensors on surveillance satellites is discussed. Cooling below about 15 K with regenerative refrigerators is difficult because of the decreasing thermal mass of the regenerator compared to that of the working material. In order to overcome this difficulty with helium gas as the working material, a heat exchanger plus a Joule-Thomson or other exponder is used. Regenerative magnetic refrigerators with magnetic solids as the working material have the same regenerator problem as gas refrigerators. This problem provides motivation for the development of nonregenerative magnetic refrigerators that span approximately 1 K to approximately 0 K. Particular emphasis is placed on high reliability and high efficiency. Calculations indicate considerable promise in this area. The principles, the potential, the problems, and the progress towards development of successful 4 to 20 K magnetic refrigerators are discussed.

Refrigerant charge management in a heat pump water heater

DOEpatents

Chen, Jie; Hampton, Justin W.

2016-07-05

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, and methods of managing refrigerant charge. Various embodiments remove idle refrigerant from a heat exchanger that is not needed for transferring heat by opening a refrigerant recovery valve and delivering the idle refrigerant from the heat exchanger to an inlet port on the compressor. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled by controlling how much refrigerant is drawn from the heat exchanger, by letting some refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and various components can be interconnected with refrigerant conduit. Some embodiments deliver refrigerant gas to the heat exchanger and drive liquid refrigerant out prior to isolating the heat exchanger.

Not all counterclockwise thermodynamic cycles are refrigerators

NASA Astrophysics Data System (ADS)

Dickerson, R. H.; Mottmann, J.

2016-06-01

Clockwise cycles on PV diagrams always represent heat engines. It is therefore tempting to assume that counterclockwise cycles always represent refrigerators. This common assumption is incorrect: most counterclockwise cycles cannot be refrigerators. This surprising result is explored here for quasi-static ideal gas cycles, and the necessary conditions for refrigeration cycles are clarified. Three logically self-consistent criteria can be used to determine if a counterclockwise cycle is a refrigerator. The most fundamental test compares the counterclockwise cycle with a correctly determined corresponding Carnot cycle. Other criteria we employ include a widely accepted description of the functional behavior of refrigerators, and a corollary to the second law that limits a refrigerator's coefficient of performance.

Magnetic refrigeration using flux compression in superconductors

NASA Technical Reports Server (NTRS)

Israelsson, U. E.; Strayer, D. M.; Jackson, H. W.; Petrac, D.

1990-01-01

The feasibility of using flux compression in high-temperature superconductors to produce the large time-varying magnetic fields required in a field cycled magnetic refrigerator operating between 20 K and 4 K is presently investigated. This paper describes the refrigerator concept and lists limitations and advantages in comparison with conventional refrigeration techniques. The maximum fields obtainable by flux compression in high-temperature supercoductor materials, as presently prepared, are too low to serve in such a refrigerator. However, reports exist of critical current values that are near usable levels for flux pumps in refrigerator applications.

Solar Refrigerators Store Life-Saving Vaccines

NASA Technical Reports Server (NTRS)

2014-01-01

Former Johnson Space Center engineer David Bergeron used his experience on the Advanced Refrigeration Technology Team to found SunDanzer Refrigeration Inc., a company specializing in solar-powered refrigerators. The company has created a battery-free unit that provides safe storage for vaccines in rural and remote areas around the world.

Self-actuating heat switches for redundant refrigeration systems

NASA Technical Reports Server (NTRS)

Chan, Chung K. (Inventor)

1988-01-01

A dual refrigeration system for cooling a sink device is described, which automatically thermally couples the cold refrigerator to the sink device while thermally isolating the warm refrigerator from the sink device. The system includes two gas gap heat switches that each thermally couples one of the refrigerators to the sink device, and a pair of sorption pumps that are coupled through tubes to the heat switches. When the first refrigerator is operated and therefore cold, the first pump which is thermally coupled to it is also cooled and adsorbs gas to withdraw it from the second heat switch, to thereby thermally isolate the sink device from the warm second refrigerator. With the second refrigerator being warm, the second pump is also warm and desorbs gas, so the gas lies in the first switch, to close that switch and therefore thermally couple the cold first refrigerator to the sink device. Thus, the heat switches are automatically switched according to the temperature of the corresponding refrigerator.

Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hessell, Edward Thomas

The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

Measurement of the Space Thermoacoustic Refrigerator Performance

DTIC Science & Technology

1990-09-01

the refrigerator was a requisite towards simplifying the process of selecting the operating frequency . The simplest method allowing for the most...LIST OF FIGURES I-1 Pulse Tube Refrigerator.............................. 3 1-2 Hofler Refrigerator.................................. 5 1-3 Acoustical...qualitative manner as did Rayleigh. The first example of an acoustic heat pump was the pulse - tube refrigerator in which Gifford and Longsworth, by applying

Temperature Scales: Celsius, Fahrenheit, Kelvin, Reamur, and Romer.

ERIC Educational Resources Information Center

Romer, Robert H.

1982-01-01

Traces the history and development of temperature scales which began with the 17th-century invention of the liquid-in-glass thermometer. Focuses on the work of Olaf Romer, Daniel Fahrenheit, Rene-Antoine de Reamur, Anders Celsius, and William Thomson (Lord Kelvin). Includes experimental work and consideration of high/low fixed points on the…

An Evaluation of the Environmental Impact of Different Commercial Supermarket Refrigeration Systems Using Low Global Warming Potential Refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar

Commercial refrigeration systems consumed 1.21 Quads of primary energy in 2010 and are known to be a major source for refrigerant charge leakage into the environment. Thus, it is important to study the environmental impact of commercial supermarket refrigeration systems and improve their design to minimize any adverse impacts. The system s Life Cycle Climate Performance (LCCP) was presented as a comprehensive metric with the aim of calculating the equivalent mass of carbon dioxide released into the atmosphere throughout its lifetime, from construction to operation and destruction. In this paper, an open source tool for the evaluation of the LCCPmore » of different air-conditioning and refrigeration systems is presented and used to compare the environmental impact of a typical multiplex direct expansion (DX) supermarket refrigeration systems based on three different refrigerants as follows: two hydrofluorocarbon (HFC) refrigerants (R-404A, and R-407F), and a low global warming potential (GWP) refrigerant (N-40). The comparison is performed in 8 US cities representing different climates. The hourly energy consumption of the refrigeration system, required for the calculation of the indirect emissions, is calculated using a widely used building energy modeling tool (EnergyPlus). A sensitivity analysis is performed to determine the impact of system charge and power plant emission factor on the LCCP results. Finally, we performed an uncertainty analysis to determine the uncertainty in total emissions for both R-404A and N-40 operated systems. We found that using low GWP refrigerants causes a considerable drop in the impact of uncertainty in the inputs related to direct emissions on the uncertainty of the total emissions of the system.« less

A multidimensional anisotropic strength criterion based on Kelvin modes

NASA Astrophysics Data System (ADS)

Arramon, Yves Pierre

A new theory for the prediction of multiaxial strength of anisotropic elastic materials was proposed by Biegler and Mehrabadi (1993). This theory is based on the premise that the total elastic strain energy of an anisotropic material subjected to multiaxial stress can be decomposed into dilatational and deviatoric modes. A multidimensional strength criterion may thus be formulated by postulating that the failure would occur when the energy stored in one of these modes has reached a critical value. However, the logic employed by these authors to formulate a failure criterion based on this theory could not be extended to multiaxial stress. In this thesis, an alternate criterion is presented which redresses the biaxial restriction by reformulating the surfaces of constant modal energy as surfaces of constant eigenstress magnitude. The resulting failure envelope, in a multidimensional stress space, is piecewise smooth. Each facet of the envelope is expected to represent the locus of failure data by a particular Kelvin mode. It is further shown that the Kelvin mode theory alone provides an incomplete description of the failure of some materials, but that this weakness can be addressed by the introduction of a set of complementary modes. A revised theory which combines both Kelvin and complementary modes is thus proposed and applied seven example materials: an isotropic concrete, tetragonal paperboard, two orthotropic softwoods, two orthotropic hardwoods and an orthotropic cortical bone. The resulting failure envelopes for these examples were plotted and, with the exception of concrete, shown to produce intuitively correct failure predictions.

Ternary Dy-Er-Al magnetic refrigerants

DOEpatents

Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

1995-07-25

A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

Kelvin-Helmholtz Instability: Lessons Learned and Ways Forward

NASA Astrophysics Data System (ADS)

Masson, A.; Nykyri, K.

2018-06-01

The Kelvin-Helmholtz instability (KHI) is a ubiquitous phenomenon across the Universe, observed from 500 m deep in the oceans on Earth to the Orion molecular cloud. Over the past two decades, several space missions have enabled a leap forward in our understanding of this phenomenon at the Earth's magnetopause. Key results obtained by these missions are first presented, with a special emphasis on Cluster and THEMIS. In particular, as an ideal instability, the KHI was not expected to produce mass transport. Simulations, later confirmed by spacecraft observations, indicate that plasma transport in Kelvin-Helmholtz (KH) vortices can arise during non-linear stage of its development via secondary process. In addition to plasma transport, spacecraft observations have revealed that KHI can also lead to significant ion heating due to enhanced ion-scale wave activity driven by the KHI. Finally, we describe what are the upcoming observational opportunities in 2018-2020, thanks to a unique constellation of multi-spacecraft missions including: MMS, Cluster, THEMIS, Van Allen Probes and Swarm.

Metal hydride-based thermal energy storage systems

DOEpatents

Vajo, John J.; Fang, Zhigang

2017-10-03

The invention provides a thermal energy storage system comprising a metal-containing first material with a thermal energy storage density of about 1300 kJ/kg to about 2200 kJ/kg based on hydrogenation; a metal-containing second material with a thermal energy storage density of about 200 kJ/kg to about 1000 kJ/kg based on hydrogenation; and a hydrogen conduit for reversibly transporting hydrogen between the first material and the second material. At a temperature of 20.degree. C. and in 1 hour, at least 90% of the metal is converted to the hydride. At a temperature of 0.degree. C. and in 1 hour, at least 90% of the metal hydride is converted to the metal and hydrogen. The disclosed metal hydride materials have a combination of thermodynamic energy storage densities and kinetic power capabilities that previously have not been demonstrated. This performance enables practical use of thermal energy storage systems for electric vehicle heating and cooling.

Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

DOEpatents

Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.

1998-04-28

Active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing.

Semiconductor-based optical refrigerator

DOEpatents

Epstein, Richard I.; Edwards, Bradley C.; Sheik-Bahae, Mansoor

2002-01-01

Optical refrigerators using semiconductor material as a cooling medium, with layers of material in close proximity to the cooling medium that carries away heat from the cooling material and preventing radiation trapping. In addition to the use of semiconducting material, the invention can be used with ytterbium-doped glass optical refrigerators.

High temperature refrigerator

DOEpatents

Steyert, Jr., William A.

1978-01-01

A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

CO2 hydrogenation on a metal hydride surface.

PubMed

Kato, Shunsuke; Borgschulte, Andreas; Ferri, Davide; Bielmann, Michael; Crivello, Jean-Claude; Wiedenmann, Daniel; Parlinska-Wojtan, Magdalena; Rossbach, Peggy; Lu, Ye; Remhof, Arndt; Züttel, Andreas

2012-04-28

The catalytic hydrogenation of CO(2) at the surface of a metal hydride and the corresponding surface segregation were investigated. The surface processes on Mg(2)NiH(4) were analyzed by in situ X-ray photoelectron spectroscopy (XPS) combined with thermal desorption spectroscopy (TDS) and mass spectrometry (MS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). CO(2) hydrogenation on the hydride surface during hydrogen desorption was analyzed by catalytic activity measurement with a flow reactor, a gas chromatograph (GC) and MS. We conclude that for the CO(2) methanation reaction, the dissociation of H(2) molecules at the surface is not the rate controlling step but the dissociative adsorption of CO(2) molecules on the hydride surface. This journal is © the Owner Societies 2012

Technical and economic aspects of hydrogen storage in metal hydrides

NASA Technical Reports Server (NTRS)

Schmitt, R.

1981-01-01

The recovery of hydrogen from such metal hydrides as LiH, MgH2, TiH2, CaH2 and FeTiH compounds is studied, with the aim of evaluating the viability of the technique for the storage of hydrogen fuel. The pressure-temperature dependence of the reactions, enthalpies of formation, the kinetics of the hydrogen absorption and desorption, and the mechanical and chemical stability of the metal hydrides are taken into account in the evaluation. Economic aspects are considered. Development of portable metal hydride hydrogen storage reservoirs is also mentioned.

Ternary Dy-Er-Al magnetic refrigerants

DOEpatents

Gschneidner, K.A. Jr.; Takeya, Hiroyuki

1995-07-25

A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

Heat Switches Providing Low-Activation Power and Quick-Switching Time for Use in Cryogenic Multi-Stage Refrigerators

NASA Technical Reports Server (NTRS)

Kimball, Mark O.; Shirron, Peter J.

2011-01-01

An adiabatic demagnetization refrigerator (ADR) is a solid-state cooler capable of achieving sub-Kelvin temperatures. It neither requires moving parts nor a density gradient in a working fluid making it ideal for use in space-based instruments. The flow of energy through the cooler is controlled by heat switches that allow heat transfer when on and isolate portions of the cooler when off. One type of switch uses helium gas as the switching medium. In the off state the gas is adsorbed in a getter thus breaking the thermal path through the switch. To activate the switch, the getter is heated to release helium into the switch body allowing it to complete the thermal path. A getter that has a small heat capacity and low thermal conductance to the body of the switch requires low-activation power. The cooler benefits from this in two ways: shorter recycle times and higher efficiency. We describe such a design here.

Pump-probe Kelvin-probe force microscopy: Principle of operation and resolution limits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murawski, J.; Graupner, T.; Milde, P., E-mail: peter.milde@tu-dresden.de

Knowledge on surface potential dynamics is crucial for understanding the performance of modern-type nanoscale devices. We describe an electrical pump-probe approach in Kelvin-probe force microscopy that enables a quantitative measurement of dynamic surface potentials at nanosecond-time and nanometer-length scales. Also, we investigate the performance of pump-probe Kelvin-probe force microscopy with respect to the relevant experimental parameters. We exemplify a measurement on an organic field effect transistor that verifies the undisturbed functionality of our pump-probe approach in terms of simultaneous and quantitative mapping of topographic and electronic information at a high lateral and temporal resolution.

Interannual variability in equatorial Kelvin waves in the upper troposphere and lower stratosphere, and relation to the background equatorial wind

NASA Astrophysics Data System (ADS)

Suzuki, J.; Nishi, N.; Fujiwara, M.; Yoneyama, K.

2016-12-01

We investigated the influence of the background wind regime on interannual variability in equatorial Kelvin waves in the upper troposphere and lower stratosphere using the European Centre for Medium-Range Weather Forecasts 40-year reanalysis data. We focused on variability in the number of Kelvin wave events as a function of the background westerly wind, given by the zonal wind index (ZWI) in the equatorial western hemisphere. The ZWI measures the strength of the upper branch of the Walker circulation in the western hemisphere. Although the ZWI is well correlated with the sea surface temperature in the Niño-3.4 region, nearly half of the peaks of positive (negative) ZWI cases occurred outside of the typical La Niña (El Niño) season (December to February), respectively. In the positive ZWI (stronger westerly) cases, both convective activity over the western Pacific and extratropical Rossby waves were enhanced. Kelvin waves over the western hemisphere appeared frequently at 200 hPa but barely reached 100 hPa due to the strong westerly wind under this level. In the negative ZWI period, on the other hand, the number of Kelvin waves at 200 hPa decreased due to the weaker convection; Kelvin waves reached 100 hPa and propagated even farther upward. We also investigated the relationship between the ZWI and the phase speed of Kelvin waves. Kelvin waves with relatively slow phase speeds are found in negative ZWI cases, but are not found in positive ZWI cases due to the westerly background wind below the altitudes where Kelvin waves commonly propagate.

SIMULATION OF NON-AZEOTROPIC REFRIGERANT MIXTURES FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER WITH COUNTERCURRENT HEAT EXCHANGES

EPA Science Inventory

The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. This RF is housed in a stan...

46 CFR 130.230 - Protection from refrigerants.

Code of Federal Regulations, 2014 CFR

2014-10-01

... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each self...

46 CFR 130.230 - Protection from refrigerants.

Code of Federal Regulations, 2011 CFR

2011-10-01

... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each self...

46 CFR 130.230 - Protection from refrigerants.

Code of Federal Regulations, 2013 CFR

2013-10-01

... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each self...

46 CFR 130.230 - Protection from refrigerants.

Code of Federal Regulations, 2012 CFR

2012-10-01

... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each self...

46 CFR 130.230 - Protection from refrigerants.

Code of Federal Regulations, 2010 CFR

2010-10-01

... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each self...

Adsorption Refrigeration System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Kai; Vineyard, Edward Allan

Adsorption refrigeration is an environmentally friendly cooling technology which could be driven by recovered waste heat or low-grade heat such as solar energy. In comparison with absorption system, an adsorption system has no problems such as corrosion at high temperature and salt crystallization. In comparison with vapor compression refrigeration system, it has the advantages of simple control, no moving parts and less noise. This paper introduces the basic theory of adsorption cycle as well as the advanced adsorption cycles such as heat and mass recovery cycle, thermal wave cycle and convection thermal wave cycle. The types, characteristics, advantages and drawbacksmore » of different adsorbents used in adsorption refrigeration systems are also summarized. This article will increase the awareness of this emerging cooling technology among the HVAC engineers and help them select appropriate adsorption systems in energy-efficient building design.« less

Reducing the Carbon Footprint of Commercial Refrigeration Systems Using Life Cycle Climate Performance Analysis: From System Design to Refrigerant Options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, Brian A; Abdelaziz, Omar; Vineyard, Edward Allan

In this paper, Life Cycle Climate Performance (LCCP) analysis is used to estimate lifetime direct and indirect carbon dioxide equivalent gas emissions of various refrigerant options and commercial refrigeration system designs, including the multiplex DX system with various hydrofluorocarbon (HFC) refrigerants, the HFC/R744 cascade system incorporating a medium-temperature R744 secondary loop, and the transcritical R744 booster system. The results of the LCCP analysis are presented, including the direct and indirect carbon dioxide equivalent emissions for each refrigeration system and refrigerant option. Based on the results of the LCCP analysis, recommendations are given for the selection of low GWP replacement refrigerantsmore » for use in existing commercial refrigeration systems, as well as for the selection of commercial refrigeration system designs with low carbon dioxide equivalent emissions, suitable for new installations.« less

Low-Thermal Conductivity Suspensions Used in the Isolation of the Salt Pills Aboard the Astro-H Adiabatic Demagnetization Refrigerator

NASA Technical Reports Server (NTRS)

Kimball, Mark O.; Shirron, Peter J.; Wegel, Donald C.; James, Bryan L.; Galassi, Nicholas M.; Faulkner, Richard L.; San Sebastian, Marcelino

2011-01-01

An adiabatic demagnetization refrigerator (ADR) utilizes the magnetocholoric effect in a paramagnetic salt to produce sub-Kelvin temperatures. It is a solid-state device that has no moving parts and does not rely upon a density gradient in a working fluid. This makes it ideal for cooling space-based instruments. ·Typically the salt is enclosed in a cylindrical pill that is suspended within the bore of a magnet. The suspension between the salt pill and magnet must be robust enough to survive a launch yet have a thermal conductance that minimizes heat from the magnet that is mechanically, and thermally, anchored to a stage at a higher temperature. Here we detail such a design that uses Kevlar(Trade Mark) as the supporting media in a system that limits motion of the salt pill axial as well as laterally with respect to the magnet bore.

Hydrogen generation using silicon nanoparticles and their mixtures with alkali metal hydrides

NASA Astrophysics Data System (ADS)

Patki, Gauri Dilip

mole of Si. We compare our silicon nanoparticles (˜10nm diameter) with commercial silicon nanopowder (<100nm diameter) and ball-milled silicon powder (325 mesh). The increase in rate upon decreasing the particle size to 10 nm was even greater than would be expected based upon the increase in surface area. While specific surface area increased by a factor of 6 in going from <100 nm to ˜10 nm particles, the hydrogen production rate increased by a factor of 150. However, in all cases, silicon requires a base (e.g. NaOH, KOH, hydrazine) to catalyze its reaction with water. Metal hydrides are also promising hydrogen storage materials. The optimum metal hydride would possess high hydrogen storage density at moderate temperature and pressure, release hydrogen safely and controllably, and be stable in air. Alkali metal hydrides have high hydrogen storage density, but exhibit high uncontrollable reactivity with water. In an attempt to control this explosive nature while maintaining high storage capacity, we mixed our silicon nanoparticles with the hydrides. This has dual benefits: (1) the hydride- water reaction produces the alkali hydroxide needed for base-catalyzed silicon oxidation, and (2) dilution with 10nm coating by, the silicon may temper the reactivity of the hydride, making the process more controllable. Initially, we analyzed hydrolysis of pure alkali metal hydrides and alkaline earth metal hydrides. Lithium hydride has particularly high hydrogen gravimetric density, along with faster reaction kinetics than sodium hydride or magnesium hydride. On analysis of hydrogen production we found higher hydrogen yield from the silicon nanoparticle—metal hydride mixture than from pure hydride hydrolysis. The silicon-hydride mixtures using our 10nm silicon nanoparticles produced high hydrogen yield, exceeding the theoretical yield. Some evidence of slowing of the hydride reaction rate upon addition of silicon nanoparticles was observed.

Control method for mixed refrigerant based natural gas liquefier

DOEpatents

Kountz, Kenneth J.; Bishop, Patrick M.

2003-01-01

In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

Refrigerant charge management in a heat pump water heater

DOEpatents

Chen, Jie; Hampton, Justin W.

2014-06-24

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.

Synthesis and hydriding properties of Li 2Mg(NH) 2

NASA Astrophysics Data System (ADS)

Markmaitree, Tippawan; Shaw, Leon L.

The phase pure Li 2Mg(NH) 2 has been synthesized via a dehydriding treatment of a ball milled 2LiNH 2 + MgH 2 mixture. This phase pure Li 2Mg(NH) 2 has been utilized to investigate its hydriding kinetics at the temperature range 180-220 °C. It is found that the hydriding process of Li 2Mg(NH) 2 is very sluggish even though it has favorable thermodynamic properties for near the ambient temperature operation. Holding at 200 °C for 10 h only results in 3.75 wt.% H 2 uptake. The detailed kinetic analysis reveals that the hydriding process of Li 2Mg(NH) 2 is diffusion-controlled. Thus, this study unambiguously indicates that the future direction to enhance the hydriding kinetics of this promising hydrogen storage material system should be to minimize the diffusion distance and increase the diffusion rate.

Maximizing NGL recovery by refrigeration optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldonedo H., A.H.

1999-07-01

PDVSA--Petroleo y Gas, S.A. has within its facilities in Lake Maracaibo two plants that extract liquids from natural gas (NGL), They use a combined mechanic refrigeration absorption with natural gasoline. Each of these plants processes 420 MMsccfd with a pressure of 535 psig and 95 F that comes from the compression plants PCTJ-2 and PCTJ-3 respectively. About 40 MMscfd of additional rich gas comes from the high pressure system. Under the present conditions these plants produce in the order of 16,800 and 23,800 b/d of NGL respectively, with a propane recovery percentage of approximately 75%, limited by the capacity ofmore » the refrigeration system. To optimize the operation and the design of the refrigeration system and to maximize the NGL recovery, a conceptual study was developed in which the following aspects about the process were evaluated: capacity of the refrigeration system, refrigeration requirements, identification of limitations and evaluation of the system improvements. Based on the results obtained it was concluded that by relocating some condensers, refurbishing the main refrigeration system turbines and using HIGH FLUX piping in the auxiliary refrigeration system of the evaporators, there will be an increase of 85% on the propane recovery, with an additional production of 25,000 b/d of NGL and 15 MMscfd of ethane rich gas.« less

Mountain Plains Learning Experience Guide: Heating, Refrigeration, & Air Conditioning.

ERIC Educational Resources Information Center

Carey, John

This Heating, Refrigeration, and Air Conditioning course is comprised of eleven individualized units: (1) Refrigeration Tools, Materials, and Refrigerant; (2) Basic Heating and Air Conditioning; (3) Sealed System Repairs; (4) Basic Refrigeration Systems; (5) Compression Systems and Compressors; (6) Refrigeration Controls; (7) Electric Circuit…

Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

DOEpatents

Gschneidner, K.A. Jr.; Pecharsky, V.K.

1998-04-28

Active magnetic regenerator and method using Gd{sub 5} (Si{sub x}Ge{sub 1{minus}x}){sub 4}, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd{sub 5} (Si{sub x} Ge{sub 1{minus}x}){sub 4}, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing. 27 figs.

Commercial Refrigeration: Heat Transfer Optimization and Energy Reduction, Measurement and Verification of a Liquid Refrigerant Pump System Retrofit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaul, Chris; Sheppy, Michael

This study describes the test results of a Refrigerant Pump System integrated into a commercial supermarket direct expansion (DX) vapor compression refrigeration system. The Liquid Refrigerant Pump System retrofit (patent-pending; application number 13/964,198) was introduced to NREL in August 2014 by CTA Architects Engineers.

Kelvin Helmholtz Instability at the Equatorial Magnetotail Boundary: MHD Simulation and Comparison with Geotail Observations

NASA Technical Reports Server (NTRS)

Fairfield, Donald H.; Otto, A.

1999-01-01

On March 24, 1995 the Geotail spacecraft observed large fluctuations of the magnetic field and plasma properties in the Low Latitude Boundary Layer (LLBL) about 15 R(sub E) tailward of the dusk meridian. Although the magnetospheric and the magnetosheath field were strongly northward, the B(sub z) component showed strong short duration fluctuations in which B(sub z) could even reach negative values. We have used two-dimensional magnetohydrodynamic simulations with magnetospheric and magnetosheath input parameters specifically chosen for this. Geotail event to identify the processes which cause the observed boundary properties. It is shown that these fluctuations can be explained by the Kelvin-Helmholtz instability if the k vector of the instability has a component along the magnetic field direction. The simulation results show many of the characteristic properties of the Geotail observations. In particular, the quasi-periodic strong fluctuations are well explained by satellite crossings through the Kelvin-Helmholtz vortices. It is illustrated how the interior structure of the Kelvin-Helmholtz vortices leads to the rapid fluctuations in the Geotail observations. Our results suggest an average Kelvin-Helmholtz wavelength of about 5 R(sub E) with a vortex size of close to 2 R(sub E) for an average repetition time of 2.5 minutes. The growth time for these waves implies a source region of about 10 to 16 R(sub E) upstream from the location of the Geotail spacecraft (i.e., near the dusk meridian). The results also indicate a considerable mass transport of magnetosheath material into the magnetosphere by magnetic reconnection in the Kelvin-Helmholtz vortices.

Hydrogen transmission/storage with a metal hydride/organic slurry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breault, R.W.; Rolfe, J.; McClaine, A.

1998-08-01

Thermo Power Corporation has developed a new approach for the production, transmission, and storage of hydrogen. In this approach, a chemical hydride slurry is used as the hydrogen carrier and storage media. The slurry protects the hydride from unanticipated contact with moisture in the air and makes the hydride pumpable. At the point of storage and use, a chemical hydride/water reaction is used to produce high-purity hydrogen. An essential feature of this approach is the recovery and recycle of the spent hydride at centralized processing plants, resulting in an overall low cost for hydrogen. This approach has two clear benefits:more » it greatly improves energy transmission and storage characteristics of hydrogen as a fuel, and it produces the hydrogen carrier efficiently and economically from a low cost carbon source. The preliminary economic analysis of the process indicates that hydrogen can be produced for $3.85 per million Btu based on a carbon cost of $1.42 per million Btu and a plant sized to serve a million cars per day. This compares to current costs of approximately $9.00 per million Btu to produce hydrogen from $3.00 per million Btu natural gas, and $25 per million Btu to produce hydrogen by electrolysis from $0.05 per Kwh electricity. The present standard for production of hydrogen from renewable energy is photovoltaic-electrolysis at $100 to $150 per million Btu.« less

Method and apparatus for de-superheating refrigerant

DOEpatents

Zess, J.A.; Drost, M.K.; Call, C.J.

1997-11-25

The present invention is an apparatus and method for de-superheating a primary refrigerant leaving a compressor wherein a secondary refrigerant is used between the primary refrigerant to be de-superheated. Reject heat is advantageously used for heat reclaim. 7 figs.

A special MJO event with a double Kelvin wave structure

NASA Astrophysics Data System (ADS)

Zhu, Lili; Li, Tim

2017-04-01

The second Madden-Julian Oscillation (MJO) event during the field campaign of the Dynamics of the MJO/Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011 (DYNAMO/CINDY2011) exhibi ted an unusual double rainband structure. Using a wavenumber-frequency spectral filtering method, we unveil that this double rainband structure arises primarily from the Kelvin wave component. The zonal phase speed of the double rainbands is about 7.9 degree per day in the equatorial Indian Ocean, being in the range of convectively coupled Kelvin wave phase speeds. The convection and circulation anomalies associated with the Kelvin wave component are characterized by two anomalous convective cells, with low-level westerly (easterly) and high (low) pressure anomalies to the west (east) of the convective centers, and opposite wind and pressure anomalies in the upper troposphere. Such a zonal wind-pressure phase relationship is consistent with the equatorial free-wave dynamics. While the free-atmospheric circulation was dominated by the first baroclinic mode vertical structure, moisture and vertical motion in the boundary layer led the convection. The convection and circulation structures derived based on the conventional MJO filter show a different characteristic. For example, the phase speed is slower (about 5.9 degree per day), and there were no double convective branches. This suggests that MJO generally involves multi-scales and it is incomplete to extract its signals by using the conventional filtering technique.

The Oak Ridge Refrigerant Management Program

NASA Technical Reports Server (NTRS)

Kevil, Thomas H.

1995-01-01

For many years, chlorofluorocarbons (CFC's) have been used by the Department of Energy's (DOE) Oak Ridge Y-12 Plant in air conditioning and process refrigeration systems. However, Title 6 of the Clean Air Act Amendments (CAAA) and Executive Order 12843 (Procurement Requirements and Policies for Federal Agencies for Ozone Depleting Substances) signed by President Clinton require, as policy, that all federal agencies maximize their use of safe, alternate refrigerants and minimize, where economically practical, the use of Class 1 refrigerants. Unfortunately, many government facilities and industrial plants have no plan or strategy in place to make this changeover, even though their air conditioning and process refrigeration equipment may not be sustainable after CFC production ends December 31, 1995. The Y-12 Plant in Oak Ridge, Tennessee, has taken an aggressive approach to complying with the CAAA and is working with private industry and other government agencies to solve tough manufacturing and application problems associated with CFC and hydrochlorofluorocarbon (HCFC) alternatives. Y-12 was the first DOE Defense Program (DP) facility to develop a long-range Stratospheric Ozone Protection Plan for refrigerant management for compliance with the CAAA. It was also the first DOE DP facility to complete detailed engineering studies on retrofitting and replacing all air conditioning and process refrigeration equipment to enable operation with alternate refrigerants. The management plan and engineering studies are models for use by other government agencies, manufacturing plants, and private industry. This presentation identifies some of the hidden pitfalls to be encountered in the accelerated phaseout schedule of CFC's and explains how to overcome and prevent these problems. In addition, it outlines the general issues that must be considered when addressing the phase-out of ozone depleting substances and gives some 'lessons learned' by Y-12 from its Refrigerant Management

Super Hydrides.

DTIC Science & Technology

1988-03-01

enantioselective synthesis Of the clinically important anti-depressants, (-)Tomoxetine, Fluoxetine (Prozac, Eli Lilly), and Nisoxetine (Scheme 1 ). Schem I a I...Scheme 1 . Another salient feature of this synthesis is that it correlated for the first time the absolute configuration of the enantiomers of...RD-RI93 710 SUPER HYDRIDES(U) PURDUE UNIV LRFRYETTE IN H C BROWN 1 / 1 NAR 88 RRO-22302.2-CN DAR29-05-K-1662 UNCLSSIFIED F/G 7/3 NI. t2S 16, L,. 10 3

Operation of Kelvin Effect in the Activities of an Antifreeze Protein: A Molecular Dynamics Simulation Study.

PubMed

Midya, Uday Sankar; Bandyopadhyay, Sanjoy

2018-03-29

Ice growth and melting inhibition activities of antifreeze proteins (AFPs) are better explained by the adsorption-inhibition mechanism. Inhibition occurs as a result of the Kelvin effect induced by adsorbed protein molecules onto the surface of seed ice crystal. However, the Kelvin effect has not been explored by the state-of-the-art experimental techniques. In this work, atomistic molecular dynamics simulations have been carried out with Tenebrio molitor antifreeze protein ( TmAFP) placed at ice-water interface to probe the Kelvin effect in the mechanism of AFPs. Simulations show that, below equilibrium melting temperature, ice growth is inhibited through the convex ice-water interface formation toward the water phase and, above equilibrium melting temperature, ice melting is inhibited through the concave ice-water interface formation inward to ice phase. Simulations further reveal that the radius of curvature of the interface formed to stop the ice growth increases with decrease in the degree of supercooling. Our results are in qualitative agreement with the theoretical prediction of the Kelvin effect and thus reveal its operation in the activities of AFPs.

Progress on 10 Kelvin cryo-cooled sapphire oscillator

NASA Technical Reports Server (NTRS)

Wang, Rabi T.; Dick, G. John; Diener, William A.

2004-01-01

We present recent progress on the 10 Kelvin Cryocooled Sapphire Oscillator (10K CSO). Included are incorporation of a new pulse tube cryocooler, cryocooler vibration comparisons between G-M and pulse-tube types, phase noise, and frequency stability tests. For the advantage of a single stage pulse tube cryocooler, we also present results for a 40K Compensated Sapphire Oscillator (40K CSO).

Development of a Proof of Concept Low Temperature Superfluid Magnetic Pump with Applications

NASA Astrophysics Data System (ADS)

Jahromi, Amir E.

State of the art particle and photon detectors such as Transition Edge Sensors (TES) and Microwave Kinetic Inductance Detectors (MKID) use large arrays of sensors or detectors for space science missions. As the size of these space science detectors increases, future astrophysics missions will require sub-Kelvin coolers over larger areas. This leads to not only increased cooling power requirements, but also a requirement for distributed sub-Kelvin cooling. Development of a proof of concept Superfluid Magnetic Pump is discussed in this work. This novel low temperature, no moving part pump can replace the existing bellows-piston driven 4He or 3He- 4He mixture compressor/circulators used in various sub Kelvin refrigeration systems such as dilution, Superfluid pulse tube, or active magnetic regenerative refrigerators. Due to its superior thermal transport properties this pump can also be used as a simple circulator of sub-Lambda 4He to distribute cooling over large surface areas. The pump discussed in this work was experimentally shown to produce a maximum flow rate of 440 mg/s (averaged over cycle), 665 mg/s (peak) and produced a maximum pressure difference of 2323 Pascal. This pump worked in an "ideal" thermodynamic state: The experimental results matched with the theoretical values predicted by a computer model. Pump curves were developed to map the performance of this pump. This successful demonstration will enable this novel pump to be put to test in suitable sub Kelvin refrigeration systems. Numerical modeling of an Active Magnetic Regenerative Refrigerator (AMRR) that uses the Superfluid Magnetic Pump (SMP) to circulate liquid 3He-4He through a magnetic regenerator is presented as a potential application of such a pump.

Method of selective reduction of halodisilanes with alkyltin hydrides

DOEpatents

D'Errico, John J.; Sharp, Kenneth G.

1989-01-01

The invention relates to the selective and sequential reduction of halodisilanes by reacting these compounds at room temperature or below with trialkyltin hydrides or dialkyltin dihydrides without the use of free radical intermediates. The alkyltin hydrides selectively and sequentially reduce the Si-Cl, Si-Br or Si-I bonds while leaving intact the Si-Si and Si-F bonds present.

Counterflow absorber for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

Dilution cycle control for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A dilution cycle control system for an absorption refrigeration system is disclosed. The control system includes a time delay relay for sensing shutdown of the absorption refrigeration system and for generating a control signal only after expiration of a preselected time period measured from the sensed shutdown of the absorption refrigeration system, during which the absorption refrigeration system is not restarted. A dilution cycle for the absorption refrigeration system is initiated in response to generation of a control signal by the time delay relay. This control system is particularly suitable for use with an absorption refrigeration system which is frequently cycled on and off since the time delay provided by the control system prevents needless dilution of the absorption refrigeration system when the system is turned off for only a short period of time and then is turned back on.

Refrigerant pressurization system with a two-phase condensing ejector

DOEpatents

Bergander, Mark [Madison, CT

2009-07-14

A refrigerant pressurization system including an ejector having a first conduit for flowing a liquid refrigerant therethrough and a nozzle for accelerating a vapor refrigerant therethrough. The first conduit is positioned such that the liquid refrigerant is discharged from the first conduit into the nozzle. The ejector includes a mixing chamber for condensing the vapor refrigerant. The mixing chamber comprises at least a portion of the nozzle and transitions into a second conduit having a substantially constant cross sectional area. The condensation of the vapor refrigerant in the mixing chamber causes the refrigerant mixture in at least a portion of the mixing chamber to be at a pressure greater than that of the refrigerant entering the nozzle and greater than that entering the first conduit.

Hydride Molecules towards Nearby Galaxies

NASA Astrophysics Data System (ADS)

Monje, Raquel R.; La, Ngoc; Goldsmith, Paul

2018-06-01

Observations carried out by the Herschel Space Observatory revealed strong spectroscopic signatures from light hydride molecules within the Milky Way and nearby active galaxies. To better understand the chemical and physical conditions of the interstellar medium, we conducted the first comprehensive survey of hydrogen fluoride (HF) and water molecular lines observed through the SPIRE Fourier Transform Spectrometer. By collecting and analyzing the sub-millimeter spectra of over two hundred sources, we found that the HF J = 1 - 0 rotational transition which occurs at approximately 1232 GHz was detected in a total of 39 nearby galaxies both in absorption and emission. The analysis will determine the main excitation mechanism of HF in nearby galaxies and provide steady templates of the chemistry and physical conditions of the ISM to be used in the early universe, where observations of hydrides are more scarce.

Manganese Silylene Hydride Complexes: Synthesis and Reactivity with Ethylene to Afford Silene Hydride Complexes.

PubMed

Price, Jeffrey S; Emslie, David J H; Britten, James F

2017-05-22

Reaction of the ethylene hydride complex trans-[(dmpe) 2 MnH(C 2 H 4 )] (1) with Et 2 SiH 2 at 20 °C afforded the silylene hydride [(dmpe) 2 MnH(=SiEt 2 )] (2 a) as the trans-isomer. By contrast, reaction of 1 with Ph 2 SiH 2 at 60 °C afforded [(dmpe) 2 MnH(=SiPh 2 )] (2 b) as a mixture of the cis (major) and trans (minor) isomers, featuring a Mn-H-Si interaction in the former. The reaction to form 2 b also yielded [(dmpe) 2 MnH 2 (SiHPh 2 )] (3 b); [(dmpe) 2 MnH 2 (SiHR 2 )] (R=Et (3 a) and Ph (3 b)) were accessed cleanly by reaction of 2 a and 2 b with H 2 , and the analogous reactions with D 2 afforded [(dmpe) 2 MnD 2 (SiHR 2 )] exclusively. Both 2 a and 2 b engaged in unique reactivity with ethylene, generating the silene hydride complexes cis-[(dmpe) 2 MnH(R 2 Si=CHMe)] (R=Et (4 a), Ph (4 b)). Compounds trans-2 a, cis-2 b, 3 b, and 4 b were crystallographically characterized, and bonding in 2 a, 2 b, 4 a, and 4 b was probed computationally. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

ARTI refrigerant database. Quarterly report, March--May 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1997-05-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information an older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some maymore » be added at a later date.« less

DEVELOPMENT OF A FABRICATION PROCESS FOR SOL-GEL/METAL HYDRIDE COMPOSITE GRANULES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, E; Eric Frickey, E; Leung Heung, L

An external gelation process was developed to produce spherical granules that contain metal hydride particles in a sol-gel matrix. Dimensionally stable granules containing metal hydrides are needed for applications such as hydrogen separation and hydrogen purification that require columns containing metal hydrides. Gases must readily flow through the metal hydride beds in the columns. Metal hydrides reversibly absorb and desorb hydrogen and hydrogen isotopes. This is accompanied by significant volume changes that cause the metal hydride to break apart or decrepitate. Repeated cycling results in very fine metal hydride particles that are difficult to handle and contain. Fine particles tendmore » to settle and pack making it more difficult to flow gases through a metal hydride bed. Furthermore, the metal hydrides can exert a significant force on the containment vessel as they expand. These problems associated with metal hydrides can be eliminated with the granulation process described in this report. Small agglomerates of metal hydride particles and abietic acid (a pore former) were produced and dispersed in a colloidal silica/water suspension to form the feed slurry. Fumed silica was added to increase the viscosity of the feed slurry which helped to keep the agglomerates in suspension. Drops of the feed slurry were injected into a 27-foot tall column of hot ({approx}70 C), medium viscosity ({approx}3000 centistokes) silicone oil. Water was slowly evaporated from the drops as they settled. The drops gelled and eventually solidified to form spherical granules. This process is referred to as external gelation. Testing was completed to optimize the design of the column, the feed system, the feed slurry composition, and the operating parameters of the column. The critical process parameters can be controlled resulting in a reproducible fabrication technique. The residual silicone oil on the surface of the granules was removed by washing in mineral spirits. The granules

Composite Materials for Hazard Mitigation of Reactive Metal Hydrides.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, Joseph William; Cordaro, Joseph Gabriel; Sartor, George B.

2012-02-01

In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heatmore » released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and

High growth rate hydride vapor phase epitaxy at low temperature through use of uncracked hydrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulte, Kevin L.; Braun, Anna; Simon, John

We demonstrate hydride vapor phase epitaxy (HVPE) of GaAs with unusually high growth rates (RG) at low temperature and atmospheric pressure by employing a hydride-enhanced growth mechanism. Under traditional HVPE growth conditions that involve growth from Asx species, RG exhibits a strong temperature dependence due to slow kinetics at the surface, and growth temperatures >750 degrees C are required to obtain RG > 60 um/h. We demonstrate that when the group V element reaches the surface in a hydride, the kinetic barrier is dramatically reduced and surface kinetics no longer limit RG. In this regime, RG is dependent on massmore » transport of uncracked AsH3 to the surface. By controlling the AsH3 velocity and temperature profile of the reactor, which both affect the degree of AsH3 decomposition, we demonstrate tuning of RG. We achieve RG above 60 um/h at temperatures as low as 560 degrees C and up to 110 um/h at 650 degrees C. We incorporate high-RG GaAs into solar cell devices to verify that the electronic quality does not deteriorate as RG is increased. The open circuit voltage (VOC), which is a strong function of non-radiative recombination in the bulk material, exhibits negligible variance in a series of devices grown at 650 degrees C with RG = 55-110 um/h. The implications of low temperature growth for the formation of complex heterostructure devices by HVPE are discussed.« less

High growth rate hydride vapor phase epitaxy at low temperature through use of uncracked hydrides

DOE PAGES

Schulte, Kevin L.; Braun, Anna; Simon, John; ...

2018-01-22

We demonstrate hydride vapor phase epitaxy (HVPE) of GaAs with unusually high growth rates (RG) at low temperature and atmospheric pressure by employing a hydride-enhanced growth mechanism. Under traditional HVPE growth conditions that involve growth from Asx species, RG exhibits a strong temperature dependence due to slow kinetics at the surface, and growth temperatures >750 degrees C are required to obtain RG > 60 um/h. We demonstrate that when the group V element reaches the surface in a hydride, the kinetic barrier is dramatically reduced and surface kinetics no longer limit RG. In this regime, RG is dependent on massmore » transport of uncracked AsH3 to the surface. By controlling the AsH3 velocity and temperature profile of the reactor, which both affect the degree of AsH3 decomposition, we demonstrate tuning of RG. We achieve RG above 60 um/h at temperatures as low as 560 degrees C and up to 110 um/h at 650 degrees C. We incorporate high-RG GaAs into solar cell devices to verify that the electronic quality does not deteriorate as RG is increased. The open circuit voltage (VOC), which is a strong function of non-radiative recombination in the bulk material, exhibits negligible variance in a series of devices grown at 650 degrees C with RG = 55-110 um/h. The implications of low temperature growth for the formation of complex heterostructure devices by HVPE are discussed.« less

Observation of single-mode, Kelvin-Helmholtz instability in a supersonic flow

DOE PAGES

Wan, W. C.; Malamud, Guy; Shimony, A.; ...

2015-10-01

This manuscript reports the first observations of the Kelvin-Helmholtz instability evolving from well-characterized seed perturbations in a steady, supersonic flow. The Kelvin-Helmholtz instability occurs when two fluids move parallel to one another at different velocities, and contributes to an intermixing of fluids and transition to turbulence. It is ubiquitous in nature and engineering, including terrestrial systems such as cloud formations, astrophysical systems such as supernovae, and laboratory systems such as fusion experiments. In a supersonic flow, the growth rate of the instability is inhibited due to effects of compressibility. These effects are still not fully understood, and hold the motivationmore » for the current work. The data presented here were obtained by developing a novel experimental platform capable of sustaining a steady shockwave over a precision-machined interface for unprecedented durations. The chosen interface was a well-characterized, single-mode sine wave, allowing us to document the evolution of individual vortices at high resolution. Understanding the behavior of individual vortices is the first of two fundamental steps towards developing a comprehensive model for the Kelvin-Helmholtz instability in a compressible flow. The results of this experiment were well reproduced with 2D hydrodynamic simulations. The platform has been extended to additional experiments, which study the evolution of different hydrodynamic instabilities in steady, supersonic flows.« less

Observation of single-mode, Kelvin-Helmholtz instability in a supersonic flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan, W. C.; Malamud, Guy; Shimony, A.

This manuscript reports the first observations of the Kelvin-Helmholtz instability evolving from well-characterized seed perturbations in a steady, supersonic flow. The Kelvin-Helmholtz instability occurs when two fluids move parallel to one another at different velocities, and contributes to an intermixing of fluids and transition to turbulence. It is ubiquitous in nature and engineering, including terrestrial systems such as cloud formations, astrophysical systems such as supernovae, and laboratory systems such as fusion experiments. In a supersonic flow, the growth rate of the instability is inhibited due to effects of compressibility. These effects are still not fully understood, and hold the motivationmore » for the current work. The data presented here were obtained by developing a novel experimental platform capable of sustaining a steady shockwave over a precision-machined interface for unprecedented durations. The chosen interface was a well-characterized, single-mode sine wave, allowing us to document the evolution of individual vortices at high resolution. Understanding the behavior of individual vortices is the first of two fundamental steps towards developing a comprehensive model for the Kelvin-Helmholtz instability in a compressible flow. The results of this experiment were well reproduced with 2D hydrodynamic simulations. The platform has been extended to additional experiments, which study the evolution of different hydrodynamic instabilities in steady, supersonic flows.« less

Detection of the fast Kelvin wave teleconnection due to El Niño-Southern Oscillation

NASA Astrophysics Data System (ADS)

Meyers, Steven D.; Melsom, Arne; Mitchum, Gary T.; O'Brien, James J.

1998-11-01

Previous analyses of the ocean state along the western American coast have often indicated unexpectedly slow and limited propagation of coastally trapped Kelvin waves associated with the El Niño-Southern Oscillation. In contrast, theoretical and numerical ocean models demonstrate that these Kelvin waves are a rapid and long-range teleconnection between the low- and high-latitude Pacific Ocean, strongly impacting both the surface coastal currents and nutrient upwelling. Sea level variations along the western coast of North America are reexamined under the assumption that tropically forced Kelvin waves are produced in bursts of several months duration. A cross-correlation analysis, restricted to mid-1982 to mid-1983, is performed between Galapagos Island and stations along western Central and North America. A coastally trapped Kelvin wave is revealed to propagate at a speed of 2-3 m s-1 from the tropical Pacific to the Aleutian Island Chain. The observed phase speed agrees with the estimated speed of a Kelvin wave based on the average density profile of the ocean near the coast. Weaker El Niño events in 1986/1987 and 1991/1992 appear to contain a combination of this remote signal and local wind forcing. The wave propagation speed calculated from the spectral phase is shown to be sensitive to the presence of other (noise) processes in the observations. This is demonstrated through an analysis of a synthetic sea level data set that contains many of the essential features of the real sea level data. A relatively small level of red noise can give a 100% expected error in the estimated propagation speed. This suggests a new explanation for this important inconsistency within dynamical oceanography.

Dynamic simulation of a reverse Brayton refrigerator

NASA Astrophysics Data System (ADS)

Peng, N.; Lei, L. L.; Xiong, L. Y.; Tang, J. C.; Dong, B.; Liu, L. Q.

2014-01-01

A test refrigerator based on the modified Reverse Brayton cycle has been developed in the Chinese Academy of Sciences recently. To study the behaviors of this test refrigerator, a dynamic simulation has been carried out. The numerical model comprises the typical components of the test refrigerator: compressor, valves, heat exchangers, expander and heater. This simulator is based on the oriented-object approach and each component is represented by a set of differential and algebraic equations. The control system of the test refrigerator is also simulated, which can be used to optimize the control strategies. This paper describes all the models and shows the simulation results. Comparisons between simulation results and experimental data are also presented. Experimental validation on the test refrigerator gives satisfactory results.

Mössbauer studies of iron hydride at high pressure

NASA Astrophysics Data System (ADS)

Choe, I.; Ingalls, R.; Brown, J. M.; Sato-Sorensen, Y.; Mills, R.

1991-07-01

We have measured in situ Mössbauer spectra of iron hydride made in a diamond anvil cell at high pressure and room temperature. The spectra show a sudden change at 3.5+/-0.5 GPa from a single hyperfine pattern to a superposition of three. The former pattern results from normal α-iron with negligible hydrogen content, and the latter from residual α-iron plus newly formed iron hydride. Between 3.5 and 10.4 GPa, the extra hydride pattern have hyperfine fields for one ranging from 276 to 263 kOe, and the other, from 317 to 309 kOe. Both have isomer shifts of about 0.4 mm/sec, and negligible quadrupole splittings. X-ray studies on quenched samples have shown that iron hydride is of double hexagonal close-packed structure, whose two nonequivalent iron sites may account for the observation of two different patterns. Even allowing for the effect of volume expansion, the observed isomer shifts for the hydride are considerably more positive than those of other metallic phases of iron. At the same time, the hyperfine fields are slightly smaller than that of α-iron. As a possible explanation, one may expect a bonding of hydrogen with iron, which would result in a small reduction of 4s electrons, possibly accompanied by a small increase of 3d electrons compared with the neutral atom in metallic iron. The difference between the hyperfine fields in the two spectra are presumably due to the different symmetry at the two iron sites.

Precooling of a dilution refrigerator

NASA Astrophysics Data System (ADS)

Pavlov, Valentin N.

A non-trivial system for Precooling of the dilution refrigerator for low-temperatureexperiments on an ISOL-facility is described in detail. Neither exchange gas in the vacuum jacket of the cryostat nor a demantable window in the 4K shield are used in this system. Instead of that the dilution refrigerator is supplemented with two capillaries and a heater in order to cool all low-temperature parts of the refrigerator down to start conditions. The, time of cooling depends on the total impedance of the first heat exchanger. Such system has been developed and tested in Dubna, and it is in operation.

Magnetocaloric Materials Revolutionize Refrigeration Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Momen, Ayyoub

Researchers at Oak Ridge National Laboratory have partnered with General Electric (GE) Appliances on a building technologies project to revolutionize today’s 100-year-old home refrigeration technology. Using magnetocaloric materials (MCM), they’ve eliminated the need for a vapor compression cycle, associated refrigerants, and their negative environmental impacts. The research team is currently working to determine the most effective means to transfer heat from the solid MCM, and using fluid passed through high-resolution microchannels shows promise. This technology has the potential to reduce energy consumption by 25%, and GE hopes to commercialize magnetocaloric refrigerators for use in homes by 2020.

EVALUATION OF OZONE-FRIENDLY HYDROFLUOROPROPANE-BASED ZEOTROPIC REFRIGERANT MIXTURES IN A LORENZ-MEUTZNER REFRIGERATOR/FREEZER

EPA Science Inventory

The two-evaporator (located in the freezer and fresh food compartments) design of the Lorenz-Meutzner (L-M) refrigerator/freezer (R/F) makes it a leading candidate for use of zeotropic refrigerant mixtures. Zeotrophic mixtures can have significant temperature glides during evapor...

Manganese Nitride Sorption Joule-Thomson Refrigerator

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Phillips, Wayne M.

1992-01-01

Proposed sorption refrigeration system of increased power efficiency combines MnxNy sorption refrigeration stage with systems described in "Regenerative Sorption Refrigerator" (NPO-17630). Measured pressure-vs-composition isotherms for reversible chemisorption of N2 in MnxNy suggest feasibility to incorporate MnxNy chemisorption stage in Joule-Thomson cryogenic system. Discovery represents first known reversible nitrogen chemisorption compression system. Has potential in nitrogen-isotope separation, nitrogen purification, or contamination-free nitrogen compression.

Hydrogen-storing hydride complexes

DOEpatents

Srinivasan, Sesha S [Tampa, FL; Niemann, Michael U [Venice, FL; Goswami, D Yogi [Tampa, FL; Stefanakos, Elias K [Tampa, FL

2012-04-10

A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.

The Evolution of the Celsius and Kelvin Temperature Scales and the State of the Art

NASA Astrophysics Data System (ADS)

Pellicer, Julio; Amparo Gilabert, M.; Lopez-Baeza, Ernesto

1999-07-01

A physical analysis is given of the evolution undergone by the Celsius and Kelvin temperature scales, from their definition to the present day. It is shown that in the temperature interval between the melting point of ice and the boiling point of water, the Celsius and Kelvin scales, both born centigrade by definition and actually become so afterwards by experimental determination as well, are not so any longer, either by definition or by experimental determination.

Dilution Refrigerator for Nuclear Refrigeration and Cryogenic Thermometry Studies

NASA Astrophysics Data System (ADS)

Nakagawa, Hisashi; Hata, Tohru

2014-07-01

This study explores the design and construction of an ultra-low temperature facility in order to realize the Provisional low-temperature scale from 0.9 mK to 1 K (PLTS-2000) in Japan, to disseminate its use through calibration services, and to study thermometry at low temperatures below 1 K. To this end, a dilution refrigerator was constructed in-house that has four sintered silver discrete heat exchangers for use as a precooling stage of a copper nuclear demagnetization stage. A melting curve thermometer attached to the mixing chamber flange could be cooled continuously to 4.0 mK using the refrigerator. The dependence of minimum temperatures on circulation rates can be explained by the calculation of Frossati's formula based on a perfect continuous counterflow heat exchanger model, assuming that the Kapitza resistance has a temperature dependence. Residual heat leakage to the mixing chamber was estimated to be around 86 nW. A nuclear demagnetization cryostat with a nuclear stage containing an effective amount of copper (51 mol in a 9 T magnetic field) is under construction, and we will presently start to work toward the realization of the PLTS-2000. In this article, the design and performance of the dilution refrigerator are reported.

Coupled Kelvin-Helmholtz and Tearing Mode Instabilities at the Mercury's Magnetopause

NASA Astrophysics Data System (ADS)

Ivanovski, S. L.; Milillo, A.; Kartalev, M.; Massetti, S.

2018-05-01

A MHD approach for numerical simulations of coupled Kelvin-Helmholtz and tearing mode instabilities has been applied to Mercury’s magnetopause and used to perform a physical parameters study constrained by the MESSENGER data.

Combined refrigeration system with a liquid pre-cooling heat exchanger

DOEpatents

Gaul, Christopher J.

2003-07-01

A compressor-pump unit for use in a vapor-compression refrigeration system is provided. The compressor-pump unit comprises a driving device including a rotatable shaft. A compressor is coupled with a first portion of the shaft for compressing gaseous refrigerant within the vapor-compression refrigeration system. A liquid pump is coupled with a second portion of the shaft for receiving liquid refrigerant having a first pressure and for discharging the received liquid refrigerant at a second pressure with the second pressure being higher than the first pressure by a predetermined amount such that the discharged liquid refrigerant is subcooled. A pre-cooling circuit is connected to the liquid pump with the pre-cooling circuit being exposed to the gaseous refrigerant whereby the gaseous refrigerant absorbs heat from the liquid refrigerant, prior to the liquid refrigerant entering the liquid pump.

Single-Mode, Supersonic Kelvin-Helmholtz Instability Experiment on OMEGA-EP

NASA Astrophysics Data System (ADS)

Wan, Wesley; Malamud, G.; Di Stefano, C.; Kuranz, C. C.; Drake, R.

2013-06-01

Laboratory laser experiments are able to produce and study phenomena that occur in astrophysical systems, allowing us to study mechanisms relevant to the formation, interaction, and destruction processes of stars and planets. These dynamic processes are strongly affected by hydrodynamic instabilities such as the Kelvin-Helmholtz instability, which arises when shear flow at an interface causes mixing between fluid layers. This instability is commonly observed at the boundary of cloud bands among gas planets, and can act as an atmospheric loss mechanism on planets with little to no intrinsic magnetic field. It is also observed in simulations of astrophysical systems including supernovae and wind-driven clumps. This poster discusses an upcoming experiment for the OMEGA-EP system that will produce a supersonic Kelvin-Helmholtz instability in the high-energy-density regime. This experiment will use a long laser pulse to create a sustained shock through two stratified layers separated by a seeded, single-mode perturbation. A high Mach number is believed to suppress the growth of the Kelvin-Helmholtz instability and, if sufficiently high, prevent growth entirely. We will be quantifying these effects using x-ray radiography. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-FG52-09NA29548, and by the National Laser User Facility Program, grant number DE-NA0000850, with additional support provided under Cooperative Agreement No. DE-FC52-08NA28302 through the Laboratory for Laser Energetics, University of Rochester.

Krypton based adsorption type cryogenic refrigerator

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Schember, Helene R. (Inventor)

1989-01-01

Krypton and a monolithic porous carbon such as Saran carbon are used respectively as the sorbate and sorbent of an adsorption type refrigerator to improve refrigeration efficiency and operational longevity.

REFRIGERATION ESPECIALLY FOR VERY LOW TEMPERATURES

DOEpatents

Kennedy, P.B.; Smith, H.R. Jr.

1960-09-13

A refrigeration system for producing very low temperatures is described. The system of the invention employs a binary mixture refrigerant in a closed constant volume, e.g., Freon and ethylene. Such mixture is compressed in the gaseous state and is then separated in a fractionating column element of the system. Thenceforth, the first liquid to separate is employed stagewise to cool and liq uefy successive portions of the refrigerant at successively lower temperatures by means of heat exchangers coupled between the successive stages. When shut down, all of the volumes of the system are interconnected and a portion of the refrigerant remains liquid at ambient temperatures so that no dangerous overpressures develop. The system is therefore rugged, simple and dependable in operation.

Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries

PubMed Central

Oumellal, Yassine; Bonnet, Jean-Pierre

2015-01-01

Summary The state of the art of conversion reactions of metal hydrides (MH) with lithium is presented and discussed in this review with regard to the use of these hydrides as anode materials for lithium-ion batteries. A focus on the gravimetric and volumetric storage capacities for different examples from binary, ternary and complex hydrides is presented, with a comparison between thermodynamic prediction and experimental results. MgH2 constitutes one of the most attractive metal hydrides with a reversible capacity of 1480 mA·h·g−1 at a suitable potential (0.5 V vs Li+/Li0) and the lowest electrode polarization (<0.2 V) for conversion materials. Conversion process reaction mechanisms with lithium are subsequently detailed for MgH2, TiH2, complex hydrides Mg2MHx and other Mg-based hydrides. The reversible conversion reaction mechanism of MgH2, which is lithium-controlled, can be extended to others hydrides as: MHx + xLi+ + xe− in equilibrium with M + xLiH. Other reaction paths—involving solid solutions, metastable distorted phases, and phases with low hydrogen content—were recently reported for TiH2 and Mg2FeH6, Mg2CoH5 and Mg2NiH4. The importance of fundamental aspects to overcome technological difficulties is discussed with a focus on conversion reaction limitations in the case of MgH2. The influence of MgH2 particle size, mechanical grinding, hydrogen sorption cycles, grinding with carbon, reactive milling under hydrogen, and metal and catalyst addition to the MgH2/carbon composite on kinetics improvement and reversibility is presented. Drastic technological improvement in order to the enhance conversion process efficiencies is needed for practical applications. The main goals are minimizing the impact of electrode volume variation during lithium extraction and overcoming the poor electronic conductivity of LiH. To use polymer binders to improve the cycle life of the hydride-based electrode and to synthesize nanoscale composite hydride can be helpful to

Method of selective reduction of polyhalosilanes with alkyltin hydrides

DOEpatents

Sharp, Kenneth G.; D'Errico, John J.

1989-01-01

The invention relates to the selective and stepwise reduction of polyhalosilanes by reacting at room temperature or below with alkyltin hydrides without the use of free radical intermediates. Alkyltin hydrides selectively and stepwise reduce the Si--Br, Si--Cl, or Si--I bonds while leaving intact any Si--F bonds. When two or more different halogens are present on the polyhalosilane, the halogen with the highest atomic weight is preferentially reduced.

Energy Efficient Operation of Ammonia Refrigeration Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohammed, Abdul Qayyum; Wenning, Thomas J; Sever, Franc

Ammonia refrigeration systems typically offer many energy efficiency opportunities because of their size and complexity. This paper develops a model for simulating single-stage ammonia refrigeration systems, describes common energy saving opportunities, and uses the model to quantify those opportunities. The simulation model uses data that are typically available during site visits to ammonia refrigeration plants and can be calibrated to actual consumption and performance data if available. Annual electricity consumption for a base-case ammonia refrigeration system is simulated. The model is then used to quantify energy savings for six specific energy efficiency opportunities; reduce refrigeration load, increase suction pressure, employmore » dual suction, decrease minimum head pressure set-point, increase evaporative condenser capacity, and reclaim heat. Methods and considerations for achieving each saving opportunity are discussed. The model captures synergistic effects that result when more than one component or parameter is changed. This methodology represents an effective method to model and quantify common energy saving opportunities in ammonia refrigeration systems. The results indicate the range of savings that might be expected from common energy efficiency opportunities.« less

Evaluation for Practical Application of HFC Refrigerants

NASA Astrophysics Data System (ADS)

Uemura, Shigehiro; Noguchi, Masahiro; Inagaki, Sadayasu; Teraoka, Takuya

Production restriction of CFCs which are used for refrigerators and air conditioners has been implemented through the international mutual agreement approved by the Montreal Protocol. Due to the less impact on the ozone layer dep1etion, alternative refrigerants for CFCs had included HCFC-123 and HCFC-22. However, H CFC-123 and HCFC-22 do not completely prevent the ozone layer depletion. This paper presents the investigation results of HFC-125, H FC-143a, HFC-152a, and HFC-32 which prevent the ozone layer depletion and are candidates for alternatives of CFCs and HCFCs. The test results of thermal stability of these refrigerants are similar to those of CFC-12 and HCFC-22. The test results show that each refrigerant has different material compatibility. The test results of lubricant solubility show that synthetic oi1s are soluble in these refrigerants, but the mineral oils currently in use for CFCs and HCFCs are not. The refrigeration performance based on the calculated thermodynamic properties corresponds with that of the experimental results.

Health effects among refrigeration repair workers exposed to fluorocarbons.

PubMed Central

Campbell, D D; Lockey, J E; Petajan, J; Gunter, B J; Rom, W N

1986-01-01

Refrigeration repair workers may be intermittently exposed to fluorocarbons and their thermal decomposition products. A case of peripheral neuropathy (distal axonopathy) in a commercial refrigeration repairman prompted an epidemiological investigation of the health of refrigeration repair workers. No additional cases of peripheral neuropathy were identified among the 27 refrigeration repair workers studied. A reference group of 14 non-refrigeration repair workers was also studied. No differences were noted between groups for the ulnar (motor and sensory), median (motor and sensory), peroneal, sural, or tibial nerve conduction velocities. Refrigeration repair workers reported palpitations and lightheadedness significantly more often than workers in the reference group. No clinical neurological or electroneurophysiological abnormalities were detected in eight refrigeration repair workers followed up for three years during continuous employment. PMID:3004555

Equatorial atmospheric Kelvin waves during El Niño episodes and their effect on stratospheric QBO.

PubMed

Das, Uma; Pan, C J

2016-02-15

Equatorial atmospheric Kelvin waves are investigated during a positive El Niño Southern Oscillation (ENSO) episode using temperature data retrieved from GPS Radio Occultation (RO) observations of FORMOSAT-3/COSMIC during the period from August 2006 to December 2013. Enhanced Kelvin wave amplitudes are observed during the El Niño episode of 2009-2010 and it is also observed that these amplitudes correlate with the Niño 3.4 index and also with outgoing longwave radiation and trade wind index. This study indicates that the enhanced equatorial atmospheric Kelvin wave amplitudes might be produced by geophysical processes that were involved in the onset and development of the El Niño episode. Further, easterly winds above the tropopause during this period favored the vertically upward propagation of these waves that induced a fast descending westerly regime by the end of 2010, where the zero-wind line is observed to take only 5 months to descend from 10 to 50 hPa. The current study presents observational evidence of enhanced Kelvin wave amplitudes during El Niño that has affected the stratospheric quasi-biennial oscillation (QBO) through wave-mean flow interactions. Earlier El Niño episodes of 1987 and 1998 are also qualitatively investigated, using reanalysis data. It is found that there might have been an enhancement in the equatorial Kelvin wave amplitudes during almost all El Niño episodes, however, an effect of a fast descending westerly is observed in the QBO only when the ambient zonal winds in the lower stratosphere favor the upward propagation of the Kelvin waves and consequently they interact with the mean flow. This study indicates that the El Niño and QBO are not linearly related and wave mean flow interactions play a very important role in connecting these two geophysical phenomena. Copyright © 2015 Elsevier B.V. All rights reserved.

Magnetocaloric Materials Revolutionize Refrigeration Technology

ScienceCinema

Momen, Ayyoub

2018-06-25

Researchers at Oak Ridge National Laboratory have partnered with General Electric (GE) Appliances on a building technologies project to revolutionize today’s 100-year-old home refrigeration technology. Using magnetocaloric materials (MCM), they’ve eliminated the need for a vapor compression cycle, associated refrigerants, and their negative environmental impacts. The research team is currently working to determine the most effective means to transfer heat from the solid MCM, and using fluid passed through high-resolution microchannels shows promise. This technology has the potential to reduce energy consumption by 25%, and GE hopes to commercialize magnetocaloric refrigerators for use in homes by 2020.

ALTERNATIVE TECHNOLOGIES FOR REFRIGERATION AND AIR-CONDITIONING APPLICATIONS

EPA Science Inventory

The report gives results of an assessment of refrigeration technologies that are alternatives to vapor compression refrigeration for use in five application categories: domestic air conditioning, commercial air conditioning, mobile air conditioning, domestic refrigeration, and co...

Education in Helium Refrigeration

NASA Astrophysics Data System (ADS)

Gistau Baguer, G. M.

2004-06-01

On the one hand, at the end of the time I was active in helium refrigeration, I noticed that cryogenics was stepping into places where it was not yet used. For example, a conventional accelerator, operating at room temperature, was to be upgraded to reach higher particle energy. On the other hand, I was a little bit worried to let what I had so passionately learned during these years to be lost. Retirement made time available, and I came gradually to the idea to teach about what was my basic job. I thought also about other kinds of people who could be interested in such lessons: operators of refrigerators or liquefiers who, often by lack of time, did not get a proper introduction to their job when they started, young engineers who begin to work in cryogenics… and so on. Consequently, I have assembled a series of lessons about helium refrigeration. As the audiences have different levels of knowledge in the field of cryogenics, I looked for a way of teaching that is acceptable for all of them. The course is split into theory of heat exchangers, refrigeration cycles, technology and operation of main components, process control, and helium purity.

Stationary Refrigeration

EPA Pesticide Factsheets

Resources for HVACR contractors, technicians, equipment owners and other regulated industry to check rules and requirements for managing refrigerant emissions, information on how to become a certified technician, and compliance assistance documents.

Crack growth through the thickness of thin-sheet Hydrided Zircaloy-4

NASA Astrophysics Data System (ADS)

Raynaud, Patrick A. C.

In recent years, the limits on fuel burnup have been increased to allow an increase in the amount of energy produced by a nuclear fuel assembly thus reducing waste volume and allowing greater capacity factors. As a result, it is paramount to ensure safety after longer reactor exposure times in the case of design-basis accidents, such as reactivity-initiated accidents (RIA). Previously proposed failure criteria do not directly address the particular cladding failure mechanism during a RIA, in which crack initiation in brittle outer-layers is immediately followed by crack growth through the thickness of the thin-wall tubing. In such a case, the fracture toughness of hydrided thin-wall cladding material must be known for the conditions of through-thickness crack growth in order to predict the failure of high-burnup cladding. The fracture toughness of hydrided Zircaloy-4 in the form of thin-sheet has been examined for the condition of through-thickness crack growth as a function of hydride content and distribution at 25°C, 300°C, and 375°C. To achieve this goal, an experimental procedure was developed in which a linear hydride blister formed across the width of a four-point bend specimen was used to inject a sharp crack that was subsequently extended by fatigue pre-cracking. The electrical potential drop method was used to monitor the crack length during fracture toughness testing, thus allowing for correlation of the load-displacement record with the crack length. Elastic-plastic fracture mechanics were used to interpret the experimental test results in terms of fracture toughness, and J-R crack growth resistance curves were generated. Finite element modeling was performed to adapt the classic theories of fracture mechanics applicable to thick-plate specimens to the case of through-thickness crack growth in thin-sheet materials, and to account for non-uniform crack fronts. Finally, the hydride microstructure was characterized in the vicinity of the crack tip by

Can Hall effect trigger Kelvin-Helmholtz instability in sub-Alfvénic flows?

NASA Astrophysics Data System (ADS)

Pandey, B. P.

2018-05-01

In the Hall magnetohydrodynamics, the onset condition of the Kelvin-Helmholtz instability is solely determined by the Hall effect and is independent of the nature of shear flows. In addition, the physical mechanism behind the super- and sub-Alfvénic flows becoming unstable is quite different: the high-frequency right circularly polarized whistler becomes unstable in the super-Alfvénic flows whereas low-frequency, left circularly polarized ion-cyclotron wave becomes unstable in the presence of sub-Alfvénic shear flows. The growth rate of the Kelvin-Helmholtz instability in the super-Alfvénic case is higher than the corresponding ideal magnetohydrodynamic rate. In the sub-Alfvénic case, the Hall effect opens up a new, hitherto inaccessible (to the magnetohydrodynamics) channel through which the partially or fully ionized fluid can become Kelvin-Helmholtz unstable. The instability growth rate in this case is smaller than the super-Alfvénic case owing to the smaller free shear energy content of the flow. When the Hall term is somewhat smaller than the advection term in the induction equation, the Hall effect is also responsible for the appearance of a new overstable mode whose growth rate is smaller than the purely growing Kelvin-Helmholtz mode. On the other hand, when the Hall diffusion dominates the advection term, the growth rate of the instability depends only on the Alfvén -Mach number and is independent of the Hall diffusion coefficient. Further, the growth rate in this case linearly increases with the Alfvén frequency with smaller slope for sub-Alfvénic flows.

Enclosure for thermoelectric refrigerator and method

NASA Technical Reports Server (NTRS)

Park, Brian V. (Inventor); McGrath, Ralph D. (Inventor)

1997-01-01

An enclosed structure is provided for use with a refrigerator having a door assembly. The enclosed structure preferably contains superinsulation materials and a plurality of matching drawers. The enclosed structure preferably includes corner joints which minimize thermal energy transfer between adjacent superinsulation panels. The refrigerator may include a cooling system having a thermoelectric device for maintaining the temperature within the refrigerator at selected values. If desired, a fluid cooling system and an active gasket may also be provided between the door assembly and the enclosed structure. The fluid cooling system preferably includes a second thermoelectric device to maintain the temperature of fluid flowing through the active gasket at a selected value. The drawers associated with the refrigerator may be used for gathering, processing, shipping and storing food or other perishable items.

Refrigeration system having standing wave compressor

DOEpatents

Lucas, Timothy S.

1992-01-01

A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

Simultaneous plate forming and hydriding of La(Fe, Si)13 magnetocaloric powders

NASA Astrophysics Data System (ADS)

Yang, Nannan; You, Caiyin; Tian, Na; Zhang, Yue; Leng, Haiyan; He, Jun

2018-04-01

In this work, we propose a way to simultaneously realize the plate forming and hydriding of La(Fe, Si)13 powders by mixing hydride MgNiYHx and solder powders Sn3.0Ag0.5Cu. Under the annealing of the green compact, the hydriding of La(Fe, Si)13 was realized through absorbing the released hydrogen from the metallic hydride MgNiYHx. The Curie temperature of La(Fe, Si)13 alloy increased from 213 K to 333 K and hysteresis reduced from 3.3 J/kg·K to 1.33 J/kg·K. Due to the bonding of Sn3.0Ag0.5Cu powders, the mechanical strength of the composite compact was highly improved in comparison to the compact of La(Fe, Si)13 powders alone.

Low cost microminiature refrigerators for large unit volume applications

NASA Technical Reports Server (NTRS)

Duboc, R. M., Jr.

1983-01-01

Photolithographic techniques were employed to fabricate small Joule-Thomson refrigerators in laminated substrates. The gas passages of a J-T refrigerator are formed by etching channels as narrow as 50 microns and as shallow as 5 microns in glass plates which are laminated together. Circular refrigerators on the order of 1.5 centimeters in diameter and .75 millimeters thick were produced which cool down to cryogenic temperatures in a few seconds, using Argon or Nitrogen, with no vacuum or radiation insulation. Smaller refrigerators are developed for both faster cooldown and low refrigeration capacity applications. By using this technology, custom refrigerators can be designed to meet specific application requirements.

Air Conditioning with Magnetic Refrigeration : An Efficient, Green Compact Cooling System Using Magnetic Refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Astronautics is developing an air conditioning system that relies on magnetic fields. Typical air conditioners use vapor compression to cool air. Vapor compression uses a liquid refrigerant to circulate within the air conditioner, absorb the heat, and pump the heat out into the external environment. Astronautics’ design uses a novel property of certain materials, called “magnetocaloric materials”, to achieve the same result as liquid refrigerants. These magnetocaloric materials essentially heat up when placed within a magnetic field and cool down when removed, effectively pumping heat out from a cooler to warmer environment. In addition, magnetic refrigeration uses nomore » ozone-depleting gases and is safer to use than conventional air conditioners which are prone to leaks.« less

A mechanical-force-driven physical vapour deposition approach to fabricating complex hydride nanostructures.

PubMed

Pang, Yuepeng; Liu, Yongfeng; Gao, Mingxia; Ouyang, Liuzhang; Liu, Jiangwen; Wang, Hui; Zhu, Min; Pan, Hongge

2014-03-24

Nanoscale hydrides desorb and absorb hydrogen at faster rates and lower temperatures than bulk hydrides because of their high surface areas, abundant grain boundaries and short diffusion distances. No current methods exist for the direct fabrication of nanoscale complex hydrides (for example, alanates, borohydrides) with unique morphologies because of their extremely high reducibility, relatively low thermodynamic stability and complicated elemental composition. Here, we demonstrate a mechanical-force-driven physical vapour deposition procedure for preparing nanoscale complex hydrides without scaffolds or supports. Magnesium alanate nanorods measuring 20-40 nm in diameter and lithium borohydride nanobelts measuring 10-40 nm in width are successfully synthesised on the basis of the one-dimensional structure of the corresponding organic coordination polymers. The dehydrogenation kinetics of the magnesium alanate nanorods are improved, and the nanorod morphology persists through the dehydrogenation-hydrogenation process. Our findings may facilitate the fabrication of such hydrides with improved hydrogen storage properties for practical applications.

A mechanical-force-driven physical vapour deposition approach to fabricating complex hydride nanostructures

NASA Astrophysics Data System (ADS)

Pang, Yuepeng; Liu, Yongfeng; Gao, Mingxia; Ouyang, Liuzhang; Liu, Jiangwen; Wang, Hui; Zhu, Min; Pan, Hongge

2014-03-01

Nanoscale hydrides desorb and absorb hydrogen at faster rates and lower temperatures than bulk hydrides because of their high surface areas, abundant grain boundaries and short diffusion distances. No current methods exist for the direct fabrication of nanoscale complex hydrides (for example, alanates, borohydrides) with unique morphologies because of their extremely high reducibility, relatively low thermodynamic stability and complicated elemental composition. Here, we demonstrate a mechanical-force-driven physical vapour deposition procedure for preparing nanoscale complex hydrides without scaffolds or supports. Magnesium alanate nanorods measuring 20-40 nm in diameter and lithium borohydride nanobelts measuring 10-40 nm in width are successfully synthesised on the basis of the one-dimensional structure of the corresponding organic coordination polymers. The dehydrogenation kinetics of the magnesium alanate nanorods are improved, and the nanorod morphology persists through the dehydrogenation-hydrogenation process. Our findings may facilitate the fabrication of such hydrides with improved hydrogen storage properties for practical applications.

High temperature metal hydrides as heat storage materials for solar and related applications.

PubMed

Felderhoff, Michael; Bogdanović, Borislav

2009-01-01

For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 degrees C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

PubMed Central

Felderhoff, Michael; Bogdanović, Borislav

2009-01-01

For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described. PMID:19333448

In situ synchrotron X-ray diffraction study of hydrides in Zircaloy-4 during thermomechanical cycling

DOE PAGES

Cinbiz, Mahmut N.; Koss, Donald A.; Motta, Arthur T.; ...

2017-02-20

The d-spacing evolution of both in-plane and out-of-plane hydrides has been studied using in situ synchrotron radiation X-ray diffraction during thermo-mechanical cycling of cold-worked stress-relieved Zircaloy-4. The structure of the hydride precipitates is such that the δ{111} d-spacing of the planes aligned with the hydride platelet face is greater than the d-spacing of the 111 planes aligned with the platelet edges. Upon heating from room temperature, the δ{111} planes aligned with hydride plate edges exhibit bi-linear thermally-induced expansion. In contrast, the d-spacing of the (111) plane aligned with the hydride plate face initially contracts upon heating. Furthermore, these experimental resultsmore » can be understood in terms of a reversal of stress state associated with precipitating or dissolving hydride platelets within the α-zirconium matrix.« less

Sorption cryogenic refrigeration - Status and future

NASA Technical Reports Server (NTRS)

Jones, Jack A.

1988-01-01

The operation principles of sorption cryogenic refrigeration are discussed. Sorption refrigerators have virtually no wear-related moving parts, have negligible vibration, and offer extremely long life (at least ten years), making it possible to obtain efficient, long life and low vibration cooling to as low as 7 K for cryogenic sensors. The physisorption and chemisorption systems recommended for various cooling ranges down to 7 K are described in detail. For long-life cooling at 4-5 K temperatures, a hybrid chemisorption-mechanical refrigeration system is recommended.

Drop-in substitute for dichlorodifluoromethane refrigerant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goble, G.H.

1993-06-01

A method for producing refrigeration in a refrigeration system designed for a dichlorodifluoromethane refrigerant is described, comprising drop-in substituting for said dichlorodifluoromethane a ternary mixture of about 2 to 20 weight percent isobutane, about 21 to 51 weight percent 1-chloro-1,1-difluoroethane, and about 41 to 71 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture; condensing said ternary mixture; and thereafter evaporating said ternary mixture in the vicinity of a body to be cooled.

Improving Control in a Joule-Thomson Refrigerator

NASA Technical Reports Server (NTRS)

Borders, James; Pearson, David; Prina, Mauro

2005-01-01

A report discusses a modified design of a Joule-Thomson (JT) refrigerator under development to be incorporated into scientific instrumentation aboard a spacecraft. In most other JT refrigerators (including common household refrigerators), the temperature of the evaporator (the cold stage) is kept within a desired narrow range by turning a compressor on and off as needed. This mode of control is inadequate for the present refrigerator because a JT-refrigerator compressor performs poorly when the flow from its evaporator varies substantially, and this refrigerator is required to maintain adequate cooling power. The proposed design modifications include changes in the arrangement of heat exchangers, addition of a clamp that would afford a controlled heat leak from a warmer to a cooler stage to smooth out temperature fluctuations in the cooler stage, and incorporation of a proportional + integral + derivative (PID) control system that would regulate the heat leak to maintain the temperature of the evaporator within a desired narrow range while keeping the amount of liquid in the evaporator within a very narrow range in order to optimize the performance of the compressor. Novelty lies in combining the temperature- and cooling-power-regulating controls into a single control system.

Atom Probe Analysis of Ex Situ Gas-Charged Stable Hydrides.

PubMed

Haley, Daniel; Bagot, Paul A J; Moody, Michael P

2017-04-01

In this work, we report on the atom probe tomography analysis of two metallic hydrides formed by pressurized charging using an ex situ hydrogen charging cell, in the pressure range of 200-500 kPa (2-5 bar). Specifically we report on the deuterium charging of Pd/Rh and V systems. Using this ex situ system, we demonstrate the successful loading and subsequent atom probe analysis of deuterium within a Pd/Rh alloy, and demonstrate that deuterium is likely present within the oxide-metal interface of a native oxide formed on vanadium. Through these experiments, we demonstrate the feasibility of ex situ hydrogen analysis for hydrides via atom probe tomography, and thus a practical route to three-dimensional imaging of hydrogen in hydrides at the atomic scale.

Refrigerated Warehouse Demand Response Strategy Guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Doug; Castillo, Rafael; Larson, Kyle

This guide summarizes demand response measures that can be implemented in refrigerated warehouses. In an appendix, it also addresses related energy efficiency opportunities. Reducing overall grid demand during peak periods and energy consumption has benefits for facility operators, grid operators, utility companies, and society. State wide demand response potential for the refrigerated warehouse sector in California is estimated to be over 22.1 Megawatts. Two categories of demand response strategies are described in this guide: load shifting and load shedding. Load shifting can be accomplished via pre-cooling, capacity limiting, and battery charger load management. Load shedding can be achieved by lightingmore » reduction, demand defrost and defrost termination, infiltration reduction, and shutting down miscellaneous equipment. Estimation of the costs and benefits of demand response participation yields simple payback periods of 2-4 years. To improve demand response performance, it’s suggested to install air curtains and another form of infiltration barrier, such as a rollup door, for the passageways. Further modifications to increase efficiency of the refrigeration unit are also analyzed. A larger condenser can maintain the minimum saturated condensing temperature (SCT) for more hours of the day. Lowering the SCT reduces the compressor lift, which results in an overall increase in refrigeration system capacity and energy efficiency. Another way of saving energy in refrigerated warehouses is eliminating the use of under-floor resistance heaters. A more energy efficient alternative to resistance heaters is to utilize the heat that is being rejected from the condenser through a heat exchanger. These energy efficiency measures improve efficiency either by reducing the required electric energy input for the refrigeration system, by helping to curtail the refrigeration load on the system, or by reducing both the load and required energy input.« less

Birth after 12 hours of oocyte refrigeration.

PubMed

Coban, Onder; Hacifazlioglu, Oguzhan; Ciray, H Nadir; Ulug, Ulun; Tekin, H Ibrahim; Bahceci, Mustafa

2010-12-01

To assess cycle outcome after oocyte refrigeration. Case report. Private IVF center. One couple in a donor oocyte program. Intracytoplasmic sperm injection and blastocyst culture after refrigeration of oocytes for 12 hours. Birth. Fourteen two-pronuclei zygotes from 17 metaphase II refrigerated oocytes resulted in transfer of two blastocysts at day 5 and cryopreservation of six excess embryos at day 6. The patient delivered one healthy male baby after 38 weeks' gestation. The successful outcome of oocyte refrigeration indicates that this protocol could be useful in circumstances in which a delay in obtaining spermatozoa arises. Copyright © 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Modeling Kelvin Wave Cascades in Superfluid Helium

NASA Astrophysics Data System (ADS)

Boffetta, G.; Celani, A.; Dezzani, D.; Laurie, J.; Nazarenko, S.

2009-09-01

We study two different types of simplified models for Kelvin wave turbulence on quantized vortex lines in superfluids near zero temperature. Our first model is obtained from a truncated expansion of the Local Induction Approximation (Truncated-LIA) and it is shown to possess the same scalings and the essential behaviour as the full Biot-Savart model, being much simpler than the later and, therefore, more amenable to theoretical and numerical investigations. The Truncated-LIA model supports six-wave interactions and dual cascades, which are clearly demonstrated via the direct numerical simulation of this model in the present paper. In particular, our simulations confirm presence of the weak turbulence regime and the theoretically predicted spectra for the direct energy cascade and the inverse wave action cascade. The second type of model we study, the Differential Approximation Model (DAM), takes a further drastic simplification by assuming locality of interactions in k-space via using a differential closure that preserves the main scalings of the Kelvin wave dynamics. DAMs are even more amenable to study and they form a useful tool by providing simple analytical solutions in the cases when extra physical effects are present, e.g. forcing by reconnections, friction dissipation and phonon radiation. We study these models numerically and test their theoretical predictions, in particular the formation of the stationary spectra, and closeness of numerics for the higher-order DAM to the analytical predictions for the lower-order DAM.

Experimental investigation of an alternating evaporator duty refrigerator/freezer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavanis, M.; Haider, I.; Radermacher, R.

1998-12-31

A bistable solenoid valve has been used to build an alternating evaporator duty (AED) domestic refrigerator/freezer. This refrigerator has two vapor compression refrigeration loops that share a common compressor, condenser, and suction line heat exchanger. Each of the refrigeration loops has an expansion device and evaporator. One evaporator is located in the fresh food compartment and the other is located in the freezer compartment. The bistable solenoid valve directs the flow of the refrigerant through one loop at a time. Only one of the two compartments is cooled at any given time. With this configuration, the food compartment is cooledmore » at a higher evaporator temperature than the freezer. Due to this, the energy efficiency of the refrigerator is improved by 8.5% over a conventional domestic refrigerator/freezer. Also, this cycle allows for completely independent temperature control of the freezer and fresh food compartments. There may be a penalty because this cycle does not allow for both loops to be simultaneously optimized. Isobutane was the only refrigerant used in this investigation.« less

Generalized equation of state for refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Y.; Sonntag, R.E.; Borgnakke, C.

1995-08-01

A new four-parameter generalized equation of state with three reference fluids has been developed for predicting thermodynamic properties of the methane and ethane-series refrigerants. The four chosen characteristic parameters are critical temperature, critical pressure, acentric factor, and the polarity factor proposed in this work. The three selected reference fluids are argon, n-butane and 1,1-difluoroethane (R-152a). When the results of this work are compared with the refrigerant experimental data, they show significant improvement over Lee and Kesler (1975) and Wu and Stiel (1985). If the characteristic parameters of the refrigerants of interest are not available, an estimation method based on themore » group contribution method is given. The ideal vapor-compression refrigeration cycle was studied using the newly developed generalized equation of state to verify the accuracy of this work.« less

46 CFR 128.410 - Ship's service refrigeration systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Ship's service refrigeration systems. 128.410 Section 128.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS... service refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated...

46 CFR 128.410 - Ship's service refrigeration systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Ship's service refrigeration systems. 128.410 Section 128.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS... service refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated...

46 CFR 128.410 - Ship's service refrigeration systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Ship's service refrigeration systems. 128.410 Section 128.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS... service refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated...

46 CFR 128.410 - Ship's service refrigeration systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Ship's service refrigeration systems. 128.410 Section 128.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS... service refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated...

46 CFR 128.410 - Ship's service refrigeration systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Ship's service refrigeration systems. 128.410 Section 128.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS... service refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated...

Investigation of Lithium Metal Hydride Materials for Mitigation of Deep Space Radiation

NASA Technical Reports Server (NTRS)

Rojdev, Kristina; Atwell, William

2016-01-01

Radiation exposure to crew, electronics, and non-metallic materials is one of many concerns with long-term, deep space travel. Mitigating this exposure is approached via a multi-faceted methodology focusing on multi-functional materials, vehicle configuration, and operational or mission constraints. In this set of research, we are focusing on new multi-functional materials that may have advantages over traditional shielding materials, such as polyethylene. Metal hydride materials are of particular interest for deep space radiation shielding due to their ability to store hydrogen, a low-Z material known to be an excellent radiation mitigator and a potential fuel source. We have previously investigated 41 different metal hydrides for their radiation mitigation potential. Of these metal hydrides, we found a set of lithium hydrides to be of particular interest due to their excellent shielding of galactic cosmic radiation. Given these results, we will continue our investigation of lithium hydrides by expanding our data set to include dose equivalent and to further understand why these materials outperformed polyethylene in a heavy ion environment. For this study, we used HZETRN 2010, a one-dimensional transport code developed by NASA Langley Research Center, to simulate radiation transport through the lithium hydrides. We focused on the 1977 solar minimum Galactic Cosmic Radiation environment and thicknesses of 1, 5, 10, 20, 30, 50, and 100 g/cm2 to stay consistent with our previous studies. The details of this work and the subsequent results will be discussed in this paper.

First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption intomore » interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.« less

Method of reducing chlorofluorocarbon refrigerant emissons to the atmosphere

DOEpatents

DeVault, Robert C.; Fairchild, Phillip D.; Biermann, Wendell J.

1990-01-01

A method is disclosed for reducing chloroflurocarbon (CFC) refrigerant emissions during removal or transfer or refrigerants from a vapor compression cooling system or heat pump which comprises contacting the refrigerant with a suitable sorbent material. The sorbent material allows for the storage and retention or the chlorofluorocarbon in non-gaseous form so that it does not tend to escape to the atmosphere where it would cause harm by contributing to ozone depletion. In other aspects of the invention, contacting of CFC refrigerants with sorbent material allows for purification and recycling of used refrigerant, and a device containing stored sorbent material can be employed in the detection of refrigerant leakage in a cooling system or heat pump.

Subcritical Kelvin-Helmholtz instability in a Hele-Shaw cell.

PubMed

Meignin, L; Gondret, P; Ruyer-Quil, C; Rabaud, M

2003-06-13

We investigate experimentally the subcritical behavior of the Kelvin-Helmholtz instability for a gas-liquid shearing flow in a Hele-Shaw cell. The subcritical curve separating the solutions of a stable plane interface and a fully saturated nonlinear wave train is determined. Experimental results are fitted by a fifth order complex Ginzburg-Landau equation whose linear coefficients are compared to theoretical ones.

REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS

EPA Science Inventory

Large refrigeration systems are found in several applications including supermarkets, cold storage warehouses, and industrial processes. The sizes of these systems are a contributing factor to their problems of high refrigerant leak rates because of the thousands of connections, ...

Synthesis and structural study of Ti-rich Mg-Ti hydrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asano, Kohta; Kim, Hyunjeong; Sakaki, Kouji

2014-02-26

Mg xTi 1-x (x = 0.15, 0.25, 0.35) alloys were synthesized by means of ball milling. Under a hydrogen pressure of 8 MPa at 423 K these Mg–Ti alloys formed a hydride phase with a face centered cubic (FCC) structure. The hydride for x = 0.25 consisted of single Mg 0.25Ti 0.75H 1.62 FCC phase but TiH 2 and MgH 2 phases were also formed in the hydrides for x = 0.15 and 0.35, respectively. X-ray diffraction patterns and the atomic pair distribution function indicated that numbers of stacking faults were introduced. There was no sign of segregation between Mgmore » and Ti in Mg 0.25Ti 0.75H 1.62. Electronic structure of Mg 0.25Ti 0.75H 1.62 was different from those of MgH 2 and TiH 2, which was demonstrated by 1H nuclear magnetic resonance. This strongly suggested that stable Mg–Ti hydride phase was formed in the metal composition of Mg 0.25Ti 0.75 without disproportion into MgH 2 and TiH 2.« less

Quantum-Circuit Refrigerator

NASA Astrophysics Data System (ADS)

MöTtöNen, Mikko; Tan, Kuan Y.; Masuda, Shumpei; Partanen, Matti; Lake, Russell E.; Govenius, Joonas; Silveri, Matti; Grabert, Hermann

Quantum technology holds great potential in providing revolutionizing practical applications. However, fast and precise cooling of the functional quantum degrees of freedom on demand remains a major challenge in many solid-state implementations, such as superconducting circuits. We demonstrate direct cooling of a superconducting resonator mode using voltage-controllable quantum tunneling of electrons in a nanoscale refrigerator. In our first experiments on this type of a quantum-circuit refrigerator, we measure the drop in the mode temperature by electron thermometry at a resistor which is coupled to the resonator mode through ohmic losses. To eliminate unwanted dissipation, we remove the probe resistor and directly observe the power spectrum of the resonator output in agreement with the so-called P(E) theory. We also demonstrate in microwave reflection experiments that the internal quality factor of the resonator can be tuned by orders of magnitude. In the future, our refrigerator can be integrated with different quantum electric devices, potentially enhancing their performance. For example, it may prove useful in the initialization of superconducting quantum bits and in dissipation-assisted quantum annealing. We acknowledge European Research Council Grant SINGLEOUT (278117) and QUESS (681311) for funding.

Solar-Powered Refrigeration System

NASA Technical Reports Server (NTRS)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2001-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure. and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Solar-Powered Refrigeration System

NASA Technical Reports Server (NTRS)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Solar Powered Refrigeration System

NASA Technical Reports Server (NTRS)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Effects of outgassing of loader chamber walls on hydriding of thin films for commercial applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Provo, James L., E-mail: jlprovo@verizon.net

2014-07-01

An important aspect of understanding industrial processing is to know the characteristics of the materials used in such processes. A study was performed to determine the effects of hydriding chamber material on the degree of hydriding for the commercial production of thin film hydride targets for various research universities, commercial companies, and government national laboratories. The goal was to increase the degree of hydriding of various thin film hydrides and to study the vacuum environment during air-exposure hydriding. For this purpose, dynamic residual gas analysis during deuterium gas hydride processing was utilized with erbium thin films, employing a special set-upmore » for direct dynamic hydride gas sampling during processing at elevated temperature and full loading gas pressure. Complete process data for (1) a copper–(1.83 wt. %)beryllium wet hydrogen fired passivated (600 °C–1 h) externally heated pipe hydriding chamber are reported. Dynamic residual gas analysis comparisons during hydriding are presented for hydriding chambers made from (2) alumina (99.8 wt. %), (3) copper (with an interior aluminum coating ∼10 k Å thick, and (4) for a stainless-steel air-fired passivated (900 °C–1 h) chamber. Dynamic data with deuterium gas in the chamber at the hydriding temperature (450 °C) showed the presence and growth of water vapor (D{sub 2}O) and related mixed ion species(H{sub 2}O{sup +}, HDO{sup +}, D{sub 2}O{sup +}, and OD{sup +}) from hydrogen isotope exchange reactions during the 1 h process time. Peaks at mass-to-charge ratios (i.e., m/e) of 12(C{sup +}), 16(CD{sub 2}{sup +}), 17(CHD{sub 2}{sup +}), and 18(CD{sub 3}{sup +}, OD{sup +}) increased for approximately the first half hour of a 1 h hydriding process and then approach steady state. Mass-to-charge peaks at 19(HDO{sup +}) and 20(D{sub 2}O{sup +}) continue to increase throughout the process cycle. Using the m/e = 20 (D{sub 2}O{sup +}) peak intensity from

Component-wise exergy and energy analysis of vapor compression refrigeration system using mixture of R134a and LPG as refrigerant

NASA Astrophysics Data System (ADS)

Gill, Jatinder; Singh, Jagdev

2018-05-01

In this work, the experimental examination was carried out using a mixture of R134a and LPG refrigerant (consisting of R134a and LPG in a proportion of 28:72 by weight) as a replacement for R134a in a vapor compression refrigeration system. Exergy and energy tests were carried out at different evaporator and condenser temperatures with controlled environmental conditions. The results showed that the exergy destruction in the compressor, condenser, evaporator, and a capillary tube of the R134a / LPG refrigeration system was found lower by approximately 11.13-3.41%, 2.24-3.43%, 12.02-13.47% and 1.54-5.61% respectively. The compressor exhibits the highest level of destruction, accompanied by a condenser, an evaporator and a capillary tube in refrigeration systems. The refrigeration capacity, COP and power consumption of the compressor of the R134a /LPG refrigeration system were detected higher and lower compared to the R134a refrigeration system by about 7.04-11.41%, 15.1-17.82%, and 3.83-8.08% respectively. Also, the miscibility of R134a and LPG blend with mineral oil discovered good. The R134a and LPG refrigerant mixture proposed in this study perform superior to R134a from component-wise exergy and energy analyses under similar experimental conditions.

Use of triammonium salt of aurin tricarboxylic acid as risk mitigant for aluminum hydride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cortes-Concepcion, Jose A.; Anton, Donald L.

2017-08-08

A process and a resulting product by process of an aluminum hydride which is modified with by physically combining in a ball milling process an aluminum hydride with a triammonium salt of aurin tricarboxylic acid. The resulting product is an aluminum hydride which is resistant to air, ambient moisture, and liquid water while maintaining useful hydrogen storage and release kinetics.

Correlation of refrigerant mass flow rate through adiabatic capillary tubes using mixture refrigerant carbondioxide and ethane for low temperature applications

NASA Astrophysics Data System (ADS)

Nasruddin, Syaka, Darwin R. B.; Alhamid, M. Idrus

2012-06-01

Various binary mixtures of carbon dioxide and hydrocarbons, especially propane or ethane, as alternative natural refrigerants to Chlorofluorocarbons (CFCs) or Hydro fluorocarbons (HFCs) are presented in this paper. Their environmental performance is friendly, with an ozone depletion potential (ODP) of zero and Global-warming potential (GWP) smaller than 20. The capillary tube performance for the alternative refrigerant HFC HCand mixed refrigerants have been widely studied. However, studies that discuss the performance of the capillary tube to a mixture of natural refrigerants, in particular a mixture of azeotrope carbon dioxide and ethane is still undeveloped. A method of empirical correlation to determine the mass flow rate and pipe length has an important role in the design of the capillary tube for industrial refrigeration. Based on the variables that effect the rate of mass flow of refrigerant in the capillary tube, the Buckingham Pi theorem formulated eight non-dimensional parameters to be developed into an empirical equations correlation. Furthermore, non-linear regression analysis used to determine the co-efficiency and exponent of this empirical correlation based on experimental verification of the results database.

Atomic-scale study of stacking faults in Zr hydrides and implications on hydride formation.

PubMed

Besson, Remy; Thuinet, L; Louchez, Marc-Antoine

2018-06-25

We performed atomic-scale ab initio calculations to investigate the stacking fault (SF) properties of the metastable zeta-Zr2H zirconium hydride. The effect of H near the SF was found to entail the existence of negative SF energies, showing that the zeta compound is probably unstable with respect to shearing in the basal plane. The effect of temperature on SFs was investigated by means of free energy calculations in the quasiharmonic approximation. This evidenced unexpectedly large temperature effects, confirming the main conclusions drawn at 0 K, in particular the zeta mechanical instability. The complex behaviour of H atoms during the shear process suggested zeta-hcp --> Zr2H[111]-fcc as a plausible shear path leading to an fcc compound with same composition as zeta. Finally, as shown by an analysis based on microelasticity, this Zr2H[111]-fcc intermediate compound may be relevant for better interpreting the currently intricate issue of hydride habit planes in zirconium. © 2018 IOP Publishing Ltd.

Hydrides of Alkaline Earth–Tetrel (AeTt) Zintl Phases: Covalent Tt–H Bonds from Silicon to Tin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Auer, Henry; Guehne, Robin; Bertmer, Marko

Zintl phases form hydrides either by incorporating hydride anions (interstitial hydrides) or by covalent bonding of H to the polyanion (polyanionic hydrides), which yields a variety of different compositions and bonding situations. Hydrides (deuterides) of SrGe, BaSi, and BaSn were prepared by hydrogenation (deuteration) of the CrB-type Zintl phases AeTt and characterized by laboratory X-ray, synchrotron, and neutron diffraction, NMR spectroscopy, and quantum-chemical calculations. SrGeD4/3–x and BaSnD4/3–x show condensed boatlike six-membered rings of Tt atoms, formed by joining three of the zigzag chains contained in the Zintl phase. These new polyanionic motifs are terminated by covalently bound H atoms withmore » d(Ge–D) = 1.521(9) Å and d(Sn–D) = 1.858(8) Å. Additional hydride anions are located in Ae4 tetrahedra; thus, the features of both interstitial hydrides and polyanionic hydrides are represented. BaSiD2–x retains the zigzag Si chain as in the parent Zintl phase, but in the hydride (deuteride), it is terminated by H (D) atoms, thus forming a linear (SiD) chain with d(Si–D) = 1.641(5) Å.« less

Hydride transfer catalysed by Escherichia coli and Bacillus subtilis dihydrofolate reductase: coupled motions and distal mutations.

PubMed

Hammes-Schiffer, Sharon; Watney, James B

2006-08-29

This paper reviews the results from hybrid quantum/classical molecular dynamics simulations of the hydride transfer reaction catalysed by wild-type (WT) and mutant Escherichia coli and WT Bacillus subtilis dihydrofolate reductase (DHFR). Nuclear quantum effects such as zero point energy and hydrogen tunnelling are significant in these reactions and substantially decrease the free energy barrier. The donor-acceptor distance decreases to ca 2.7 A at transition-state configurations to enable the hydride transfer. A network of coupled motions representing conformational changes along the collective reaction coordinate facilitates the hydride transfer reaction by decreasing the donor-acceptor distance and providing a favourable geometric and electrostatic environment. Recent single-molecule experiments confirm that at least some of these thermally averaged equilibrium conformational changes occur on the millisecond time-scale of the hydride transfer. Distal mutations can lead to non-local structural changes and significantly impact the probability of sampling configurations conducive to the hydride transfer, thereby altering the free-energy barrier and the rate of hydride transfer. E. coli and B. subtilis DHFR enzymes, which have similar tertiary structures and hydride transfer rates with 44% sequence identity, exhibit both similarities and differences in the equilibrium motions and conformational changes correlated to hydride transfer, suggesting a balance of conservation and flexibility across species.

Neon turbo-Brayton cycle refrigerator for HTS power machines

NASA Astrophysics Data System (ADS)

Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

2012-06-01

We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

46 CFR 98.25-35 - Refrigerated systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically... auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to...

46 CFR 98.25-35 - Refrigerated systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically... auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to...

46 CFR 98.25-35 - Refrigerated systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically... auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to...

46 CFR 98.25-35 - Refrigerated systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically... auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to...

46 CFR 98.25-35 - Refrigerated systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically... auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to...

Evaluating alternative refrigerants for high ambient temperature environments

DOE PAGES

Abdelaziz, Omar; Shrestha, Som S.

2016-01-01

According to the Montreal Protocol, developing countries have started the phase out schedule of the ozone depleting substances, including HCFC refrigerants, in 2015 and expect them to reach 35% reduction in 2020. This commitment to the start the phase out of HCFC refrigerants, especially R-22, in developing countries is seen as an opportunity to introduce lower Global Warming Potential (GWP) refrigerants. Furthermore, this paper summarizes an investigation into the performance of lower GWP refrigerants in high ambient temperature environments, experienced in some of the developed countries, in mini-split air conditioning units.

The Thermodynamics of a Refrigeration System.

ERIC Educational Resources Information Center

Azevedo e Silva, J. F. M.

1991-01-01

An attempt to clarify the teaching of some of the concepts of thermodynamics through the observation of an experiment with an ordinary refrigeration system is presented. The cycle of operation in the refrigeration system and the individual processes in the cycle are described. (KR)

Method of making alkali metal hydrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pecharsky, Vitalij K.; Gupta, Shalabh; Pruski, Marek

A method is provided for making alkali metal hydrides by mechanochemically reacting alkali metal and hydrogen gas under mild temperature (e.g room temperature) and hydrogen pressure conditions without the need for catalyst, solvent, and intentional heating or cooling.

Space shuttle orbiter mechanical refrigeration system

NASA Technical Reports Server (NTRS)

Williams, J. L.

1974-01-01

A radiator/condenser was designed which is efficient in both condensation (refrigeration) and liquid phase (radiator) operating modes, including switchover from the refrigeration mode to the radiator mode and vice versa. A method for predicting the pressure drop of a condensing two-phase flow in zero-gravity was developed along with a method for predicting the flow regime which would prevail along the condensation path. The hybrid refrigeration system was assembled with the two radiator/condenser panels installed in a space environment simulator. The system was tested under both atmospheric and vacuum conditions. Results of the tests are presented.

Storing energy in metal hydrides - A review of the physical metallurgy

NASA Astrophysics Data System (ADS)

Ivey, D. G.; Northwood, D. O.

1983-02-01

The properties of metal hydrides, which are significant in terms of their potential as a hydrogen storage medium, are discussed. Attention is given to bonding and electronic factors of metal hydrides, which, when combined with hydrogen, form saline, ionic, metallic, and covalent bonds, with the resultant materials being either solid, liquid, or gaseous. Metallic bonds are the most promising for hydrogen storage, and involve most of the elements of groups IIIA-VIIIA in the periodic table. An analysis of the thermodynamics and kinetics of metal hydrides is presented, noting the effects of alloy composition, crystal structure, and contaminants on the effectiveness of the materials as hydrides. Hysteresis has been found to occur when the transition pressure in a pressure-composition-temperature curve is higher for absorption than for desorption, although the actual causes for hysteresis are not understood. The AB group of intermetallics has been determined to store hydrogen at the lowest cost. Examples from tests using the AB compounds are outlined, and attempts to rectify storage requirement deficiencies by adjusting the alloy compositions are described.

Refrigeration Compressors for the Altitude Wind Tunnel

NASA Image and Video Library

1944-09-21

These compressors inside the Refrigeration Building at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory were used to generate cold temperatures in the Altitude Wind Tunnel (AWT) and Icing Research Tunnel. The AWT was a large facility that simulated actual flight conditions at high altitudes. The two primary aspects of altitude simulation are the reduction of the air pressure and the decrease of temperature. The Icing Research Tunnel was a smaller facility in which water droplets were added to the refrigerated air stream to simulate weather conditions that produced ice buildup on aircraft. The military pressured the NACA to complete the tunnels quickly so they could be of use during World War II. The NACA engineers struggled with the design of this refrigeration system, so Willis Carrier, whose Carrier Corporation had pioneered modern refrigeration, took on the project. The Carrier engineers devised the largest cooling system of its kind in the world. The system could lower the tunnels’ air temperature to –47⁰ F. The cooling system was powered by 14 Carrier and York compressors, seen in this photograph, which were housed in the Refrigeration Building between the two wind tunnels. The compressors converted the Freon 12 refrigerant into a liquid. The refrigerant was then pumped into zig-zag banks of cooling coils inside the tunnels’ return leg. The Freon absorbed heat from the airflow as it passed through the coils. The heat was transferred to the cooling water and sent to the cooling tower where it was dissipated into the atmosphere.

Metal hydride hydrogen compression: Recent advances and future prospects

DOE PAGES

Bowman, Jr., Robert C.; Yartys, Volodymyr A.; Lototskyy, Mykhaylo V.; ...

2016-03-17

Metal hydride (MH) thermal sorption compression is one of the more important applications of the metal hydrides. The present paper reviews recent advances in the field based on the analysis of the fundamental principles of this technology. The performances when boosting hydrogen pressure, along with two- and three-step compression units are analyzed. The paper includes also a theoretical modeling of a two-stage compressor aimed at both describing the performance of the experimentally studied systems, but, also, on their optimization and design of more advanced MH compressors. Business developments in the field are reviewed for the Norwegian company HYSTORSYS AS andmore » the South African Institute for Advanced Materials Chemistry. Finally, future prospects are outlined presenting the role of the metal hydride compression in the overall development of the hydrogen driven energy systems. Lastly, the work is based on the analysis of the development of the technology in Europe, USA and South Africa.« less

7 CFR 3300.37 - Testing of a mechanical refrigerating appliance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Testing of a mechanical refrigerating appliance. 3300... SPECIAL EQUIPMENT Procedures for Separate Testing of Mechanical Refrigerating Appliances § 3300.37 Testing of a mechanical refrigerating appliance. For separate testing of a mechanical refrigerating appliance...

Determination of hydride affinities of various aldehydes and ketones in acetonitrile.

PubMed

Zhu, Xiao-Qing; Chen, Xi; Mei, Lian-Rui

2011-05-06

The hydride affinities of 21 typical aldehydes and ketones in acetonitrile were determined by using an experimental method, which is valuable for chemists choosing suitable reducing agents to reduce them. The focus of this paper is to introduce a very facile experimental method, which can be used to determine the hydride affinities of various carbonyl compounds in solution.

Vaccine refrigeration: thinking outside of the box.

PubMed

McColloster, Patrick J; Martin-de-Nicolas, Andres

2014-01-01

This commentary reviews recent changes in Centers for Disease Control (CDC) vaccine storage guidelines that were developed in response to an investigative report by the Office of the Inspector General. The use of temperature data loggers with probes residing in glycol vials is advised along with storing vaccines in pharmaceutical refrigerators. These refrigerators provide good thermal distribution but can warm to 8 °C in less than one hour after the power is discontinued. Consequently, electric grid instability influences appropriate refrigerator selection and the need for power back-up. System Average Interruption Duration Index (SAIDI) values quantify this instability and can be used to formulate region-specific guidelines. A novel aftermarket refrigerator with a battery back-up power supply and microprocessor control system is also described.

Refrigeration of rainbow trout gametes and embryos.

PubMed

Babiak, Igor; Dabrowski, Konrad

2003-12-01

Prolonged access to early embryos composed of undifferentiated, totipotent blastomeres is desirable in situations when multiple collections of gametes are not possible. The objective of the present study is to examine whether the refrigeration of rainbow trout Oncorhynchus mykiss gametes and early embryos would be a suitable, reliable, and efficient tool for prolonging the availability of early developmental stages up to the advanced blastula stage. The study was conducted continuously during fall, winter, and spring spawning seasons. In all, more than 500 experimental variants were performed involving individual samples from 26 females and 33 males derived from three strains. These strains represented three possible circumstances. In optimal one, gametes from good quality donors were obtained soon after ovulation. In the two non-optimal sources, either donors were of poor genetic quality or gametes were collected from a distant location and transported as unfertilized gametes. A highly significant effect of variability of individual sample quality on efficiency of gamete and embryo refrigeration was revealed. The source of gametes significantly affected viability of refrigerated oocytes and embryos, but not spermatozoa. On average, oocytes from optimal source retained full fertilization viability for seven days of chilled storage, significantly longer than from non-optimal sources. Spermatozoa, regardless of storage method, retained full fertilization ability for the first week of storage. Refrigeration of embryos at 1.4+/-0.4 degrees C significantly slowed the development. Two- week-old embryos were still in blastula stage. Average survival rate of embryos refrigerated for 10 days and then transferred to regular incubation temperatures of 9-14 degrees C was 92% in optimal and 51 and 71% in non-optimal source variants. No effect of gamete and embryo refrigeration on the occurrence of developmental abnormalities was observed. Cumulative refrigeration of oocytes and

Optimal low symmetric dissipation Carnot engines and refrigerators

NASA Astrophysics Data System (ADS)

de Tomás, C.; Hernández, A. Calvo; Roco, J. M. M.

2012-01-01

A unified optimization criterion for Carnot engines and refrigerators is proposed. It consists of maximizing the product of the heat absorbed by the working system times the efficiency per unit time of the device, either the engine or the refrigerator. This criterion can be applied to both low symmetric dissipation Carnot engines and refrigerators. For engines the criterion coincides with the maximum power criterion and then the Curzon-Ahlborn efficiency ηCA=1-Tc/Th is recovered, where Th and Tc are the temperatures of the hot and cold reservoirs, respectively [Esposito, Kawai, Lindenberg, and Van den Broeck, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.150603 105, 150603 (2010)]. For refrigerators the criterion provides the counterpart of Curzon-Ahlborn efficiency for refrigerators ɛCA=[1/(1-(Tc/Th)]-1, first derived by Yan and Chen for the particular case of an endoreversible Carnot-type refrigerator with linear (Newtonian) finite heat transfer laws [Yan and Chen, J. Phys. D: Appl. Phys.JPAPBE0022-372710.1088/0022-3727/23/2/002 23, 136 (1990)].

Homogeneous hydride formation path in α-Zr: Molecular dynamics simulations with the charge-optimized many-body potential

DOE PAGES

Zhang, Yongfeng; Bai, Xian-Ming; Yu, Jianguo; ...

2016-06-01

A formation path for homogeneous γ hydride formation in hcp α-Zr, from solid solution to the ζ and then the γ hydride, was demonstrated using molecular static calculations and molecular dynamic simulations with the charge-optimized many-body (COMB) potential. Hydrogen has limited solubility in α-Zr. Once the solubility limit is exceeded, the stability of solid solution gives way to that of coherent hydride phases such as the ζ hydride by planar precipitation of hydrogen. At finite temperatures, the ζ hydride goes through a partial hcp-fcc transformation via 1/3 <1¯100> slip on the basal plane, and transforms into a mixture of γmore » hydride and α-Zr. In the ζ hydride, slip on the basal plane is favored thermodynamically with negligible barrier, and is therefore feasible at finite temperatures without mechanical loading. The transformation process involves slips of three equivalent shear partials, in contrast to that proposed in the literature where only a single shear partial was involved. The adoption of multiple slip partials minimizes the macroscopic shape change of embedded hydride clusters and the shear strain accumulation in the matrix, and thus reduces the overall barrier needed for homogeneous γ hydride formation. In conclusion, this formation path requires finite temperatures for hydrogen diffusion without mechanical loading. Therefore, it should be effective at the cladding operating conditions.« less

Metal Hydride Compression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Terry A.; Bowman, Robert; Smith, Barton

Conventional hydrogen compressors often contribute over half of the cost of hydrogen stations, have poor reliability, and have insufficient flow rates for a mature FCEV market. Fatigue associated with their moving parts including cracking of diaphragms and failure of seal leads to failure in conventional compressors, which is exacerbated by the repeated starts and stops expected at fueling stations. Furthermore, the conventional lubrication of these compressors with oil is generally unacceptable at fueling stations due to potential fuel contamination. Metal hydride (MH) technology offers a very good alternative to both conventional (mechanical) and newly developed (electrochemical, ionic liquid pistons) methodsmore » of hydrogen compression. Advantages of MH compression include simplicity in design and operation, absence of moving parts, compactness, safety and reliability, and the possibility to utilize waste industrial heat to power the compressor. Beyond conventional H2 supplies of pipelines or tanker trucks, another attractive scenario is the on-site generating, pressuring and delivering pure H 2 at pressure (≥ 875 bar) for refueling vehicles at electrolysis, wind, or solar generating production facilities in distributed locations that are too remote or widely distributed for cost effective bulk transport. MH hydrogen compression utilizes a reversible heat-driven interaction of a hydride-forming metal alloy with hydrogen gas to form the MH phase and is a promising process for hydrogen energy applications [1,2]. To deliver hydrogen continuously, each stage of the compressor must consist of multiple MH beds with synchronized hydrogenation & dehydrogenation cycles. Multistage pressurization allows achievement of greater compression ratios using reduced temperature swings compared to single stage compressors. The objectives of this project are to investigate and demonstrate on a laboratory scale a two-stage MH hydrogen (H 2) gas compressor with a feed pressure

Method for preparing hydride configurations and reactive metal surfaces

DOEpatents

Silver, G.L.

1984-05-18

A method for preparing reactive metal surfaces, particularly uranium surfaces is disclosed, whereby the metal is immediately reactive to hydrogen gas at room temperature and low pressure. The metal surfaces are first pretreated by exposure to an acid which forms an adherent hydride-bearing composition on the metal surface. Subsequent heating of the pretreated metal at a temperature sufficient to decompose the hydride coating in vacuum or inert gas renders the metal surface instantaneously reactive to hydrogen gas at room temperature and low pressure.

Phase I. Lanthanum-based Start Materials for Hydride Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gschneidner, K. A.; Schmidt, F. A.; Frerichs, A. E.

The purpose of Phase I of this work is to focus on developing a La-based start material for making nickel-metal (lanthanum)-hydride batteries based on our carbothermic-silicon process. The goal is to develop a protocol for the manufacture of (La 1-xR x)(Ni 1-yM y)(Si z), where R is a rare earth metal and M is a non-rare earth metal, to be utilized as the negative electrode in nickel-metal hydride (NiMH) rechargeable batteries.

Heat pump employing optimal refrigerant compressor for low pressure ratio applications

DOEpatents

Ecker, Amir L.

1982-01-01

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler for circulating the fluid in heat exchange relationship with a refrigerant fluid; two refrigerant heat exchangers; one for effecting the heat exchange with the fluid and a second refrigerant-heat exchange fluid heat exchanger for effecting a low pressure ratio of compression of the refrigerant; a rotary compressor for compressing the refrigerant with low power consumption at the low pressure ratio; at least one throttling valve connecting at the inlet side of heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit serially connecting the above elements; refrigerant in the circuit; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant.

Conversion and origin of normal and abnormal temperature dependences of kinetic isotope effect in hydride transfer reactions.

PubMed

Zhu, Xiao-Qing; Li, Xiu-Tao; Han, Su-Hui; Mei, Lian-Rui

2012-05-18

The effects of substituents on the temperature dependences of kinetic isotope effect (KIE) for the reactions of the hydride transfer from the substituted 5-methyl-6-phenyl-5,6-dihydrophenanthridine (G-PDH) to thioxanthylium (TX(+)) in acetonitrile were examined, and the results show that the temperature dependences of KIE for the hydride transfer reactions can be converted by adjusting the nature of the substituents in the molecule of the hydride donor. In general, electron-withdrawing groups can make the KIE to have normal temperature dependence, but electron-donating groups can make the KIE to have abnormal temperature dependence. Thermodynamic analysis on the possible pathways of the hydride transfer from G-PDH to TX(+) in acetonitrile suggests that the transfers of the hydride anion in the reactions are all carried out by the concerted one-step mechanism whether the substituent is an electron-withdrawing group or an electron-donating group. But the examination of Hammett-type free energy analysis on the hydride transfer reactions supports that the concerted one-step hydride transfer is not due to an elementary chemical reaction. The experimental values of KIE at different temperatures for the hydride transfer reactions were modeled by using a kinetic equation formed according to a multistage mechanism of the hydride transfer including a returnable charge-transfer complex as the reaction intermediate; the real mechanism of the hydride transfer and the root that why the temperature dependences of KIE can be converted as the nature of the substituents are changed were discovered.

Convectively coupled Kelvin waves in aquachannel simulations: 2. Life cycle and dynamical-convective coupling

NASA Astrophysics Data System (ADS)

Blanco, Joaquín. E.; Nolan, David S.; Mapes, Brian E.

2016-10-01

This second part of a two-part study uses Weather Research and Forecasting simulations with aquachannel and aquapatch domains to investigate the time evolution of convectively coupled Kelvin waves (CCKWs). Power spectra, filtering, and compositing are combined with object-tracking methods to assess the structure and phase speed propagation of CCKWs during their strengthening, mature, and decaying phases. In this regard, we introduce an innovative approach to more closely investigate the wave (Kelvin) versus entity (super cloud cluster or "SCC") dualism. In general, the composite CCKW structures represent a dynamical response to the organized convective activity. However, pressure and thermodynamic fields in the boundary layer behave differently. Further analysis of the time evolution of pressure and low-level moist static energy finds that these fields propagate eastward as a "moist" Kelvin wave (MKW), faster than the envelope of organized convection or SCC. When the separation is sufficiently large the SCC dissipates, and a new SCC generates to the east, in the region of strongest negative pressure perturbations. We revisit the concept itself of the "coupling" between convection and dynamics, and we also propose a conceptual model for CCKWs, with a clear distinction between the SCC and the MKW components.

Two stage sorption type cryogenic refrigerator including heat regeneration system

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Wen, Liang-Chi (Inventor); Bard, Steven (Inventor)

1989-01-01

A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system is disclosed. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

Two-statge sorption type cryogenic refrigerator including heat regeneration system

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Wen, Liang-Chi (Inventor); Bard, Steven (Inventor)

1989-01-01

A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

Release of hydrogen from nanoconfined hydrides by application of microwaves

NASA Astrophysics Data System (ADS)

Sanz-Moral, Luis Miguel; Navarrete, Alexander; Sturm, Guido; Link, Guido; Rueda, Miriam; Stefanidis, Georgios; Martín, Ángel

2017-06-01

The release of hydrogen from solid hydrides by thermolysis can be improved by nanoconfinement of the hydride in a suitable micro/mesoporous support, but the slow heat transfer by conduction through the support can be a limitation. In this work, a C/SiO2 mesoporous material has been synthesized and employed as matrix for nanoconfinement of hydrides. The matrix showed high surface area and pore volume (386 m2/g and 1.41 cm3/g), which enabled the confinement of high concentrations of hydride. Furthermore, by modification of the proportion between C and SiO2, the dielectric properties of the complex could be modified, making it susceptible to microwave heating. As with this heating method the entire sample is heated simultaneously, the heat transfer resistances associated to conduction were eliminated. To demonstrate this possibility, ethane 1,2-diaminoborane (EDAB) was embedded on the C/SiO2 matrix at concentrations ranging from 11 to 31%wt using a wet impregnation method, and a device appropriate for hydrogen release from this material by application of microwaves was designed with the aid of a numerical simulation. Hydrogen liberation tests by conventional heating and microwaves were compared, showing that by microwave heating hydrogen release can be initiated and stopped in shorter times.

Experimental progress of a 4K VM/PT hybrid cryocooler for pre-cooling 1K sorption cooler

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Zhang, Tong; Wang, Jue; Chen, Liubiao; Guo, Jia; Zhou, Yuan; Wang, Junjie

2017-12-01

Sub-kelvin refrigerator has many applications in space detector and manned space station, such as for the transition-edge superconducting (TES) bolometers operated in the 50 mK range. In order to meet the requirement of space applications, the high efficient, vibration free and high stability refrigerator need to be designed. VM/PT hybrid cryocooler is a new type cryocooler capable of attaining temperature below 4K. As a low frequency Stirling type cryocooler, it has the advantages of high stability and high efficiency. Combined with the vibration free sorption cooler and ADR refrigerator, a novel sub-kelvin cooling chain can be designed for the TES bolometer. This paper presents the recent experimental progress of the 4K VM/PT hybrid cryocooler in our laboratory. By optimizing of regenerators, phase shifters and heat exchangers, a lowest temperature of 2.6K was attained. Based on this cryocooler, a preliminary sorption cooler could be designed.

Wheel-type magnetic refrigerator

DOEpatents

Barclay, J.A.

1983-10-11

The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load. 7 figs.

Wheel-type magnetic refrigerator

DOEpatents

Barclay, John A.

1983-01-01

The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.

Wheel-type magnetic refrigerator

DOEpatents

Barclay, J.A.

1982-01-20

The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.

21 CFR 1250.34 - Refrigeration equipment.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Refrigeration equipment. 1250.34 Section 1250.34 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment...

21 CFR 1250.34 - Refrigeration equipment.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Refrigeration equipment. 1250.34 Section 1250.34 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment...

21 CFR 1250.34 - Refrigeration equipment.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Refrigeration equipment. 1250.34 Section 1250.34 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment...

21 CFR 1250.34 - Refrigeration equipment.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Refrigeration equipment. 1250.34 Section 1250.34 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment...

21 CFR 1250.34 - Refrigeration equipment.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Refrigeration equipment. 1250.34 Section 1250.34 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment...

7 CFR 58.154 - Refrigerated storage.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Refrigerated storage. 58.154 Section 58.154... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.154 Refrigerated storage. Finished product in containers subject to such conditions that will...

7 CFR 58.154 - Refrigerated storage.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Refrigerated storage. 58.154 Section 58.154... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.154 Refrigerated storage. Finished product in containers subject to such conditions that will...

7 CFR 58.154 - Refrigerated storage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Refrigerated storage. 58.154 Section 58.154... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.154 Refrigerated storage. Finished product in containers subject to such conditions that will...

7 CFR 58.154 - Refrigerated storage.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Refrigerated storage. 58.154 Section 58.154... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.154 Refrigerated storage. Finished product in containers subject to such conditions that will...

7 CFR 58.154 - Refrigerated storage.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Refrigerated storage. 58.154 Section 58.154... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.154 Refrigerated storage. Finished product in containers subject to such conditions that will...

Hydrogen storage as a hydride. Citations from the International Aerospace Abstracts data base

NASA Technical Reports Server (NTRS)

Zollars, G. F.

1980-01-01

These citations from the international literature concern the storage of hydrogen in various metal hydrides. Binary and intermetallic hydrides are considered. Specific alloys discussed are iron titanium, lanthanium nickel, magnesium copper and magnesium nickel among others.

Titanium compacts produced by the pulvimetallurgical hydride-dehydride method for biomedical applications.

PubMed

Barreiro, M M; Grana, D R; Kokubu, G A; Luppo, M I; Mintzer, S; Vigna, G

2010-04-01

Titanium powder production by the hydride-dehydride method has been developed as a non-expensive process. In this work, commercially pure grade two Ti specimens were hydrogenated. The hydrided material was milled in a planetary mill. The hydrided titanium powder was dehydrided and then sieved to obtain a particle size between 37 and 125 microm in order to compare it with a commercial powder produced by chemical reduction with a particle size lower than 150 microm. Cylindrical green compacts were obtained by uniaxial pressing of the powders at 343 MPa and sintering in vacuum. The powders and the density of sintered compacts were characterized, the oxygen content was measured and in vivo tests were performed in the tibia bones of Wistar rats in order to evaluate their biocompatibility. No differences were observed between the materials which were produced either with powders obtained by the hydride-dehydride method or with commercial powders produced by chemical reduction regarding modifications in compactation, sintering and biological behaviour.

The development of nickel-metal hydride technology for use in aerospace applications

NASA Technical Reports Server (NTRS)

Rampel, Guy; Johnson, Herschel; Dell, Dan; Wu, Tony; Puglisi, Vince

1992-01-01

The nickel metal hydride technology for battery application is relatively immature even though this technology was made widely known by Philips' scientists as long ago as 1970. Recently, because of the international environmental regulatory pressures being placed on cadmium in the workplace and in disposal practices, battery companies have initiated extensive development programs to make this technology a viable commercial operation. These hydrides do not pose a toxilogical threat as does cadmium. Also, they provide a higher energy density and specific energy when compared to the other nickel based battery technologies. For these reasons, the nickel metal hydride electrochemisty is being evaluated as the next power source for varied applications such as laptop computers, cellular telephones, electric vehicles, and satellites. A parallel development effort is under way to look at aerospace applications for nickel metal hydride cells. This effort is focused on life testing of small wound cells of the commercial type to validate design options and development of prismatic design cells for aerospace applications.

Compatibility of refrigerants and lubricants with elastomers. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamed, G.R.; Seiple, R.H.; Taikum, Orawan

1994-01-01

The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. In part I of the program the swell behavior in the test fluids has been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed fro the refrigerant test fluids and 24 hours after removal from the lubricants. Part IImore » of the testing program includes the evaluation of tensile strength, hardness, weight, and dimensional changes after immersion aging in refrigerant/lubricant mixtures of selected elastomer formulations at elevated temperature and pressure.« less

Pumping liquid metal at high temperatures up to 1,673 kelvin

NASA Astrophysics Data System (ADS)

Amy, C.; Budenstein, D.; Bagepalli, M.; England, D.; Deangelis, F.; Wilk, G.; Jarrett, C.; Kelsall, C.; Hirschey, J.; Wen, H.; Chavan, A.; Gilleland, B.; Yuan, C.; Chueh, W. C.; Sandhage, K. H.; Kawajiri, Y.; Henry, A.

2017-10-01

Heat is fundamental to power generation and many industrial processes, and is most useful at high temperatures because it can be converted more efficiently to other types of energy. However, efficient transportation, storage and conversion of heat at extreme temperatures (more than about 1,300 kelvin) is impractical for many applications. Liquid metals can be very effective media for transferring heat at high temperatures, but liquid-metal pumping has been limited by the corrosion of metal infrastructures. Here we demonstrate a ceramic, mechanical pump that can be used to continuously circulate liquid tin at temperatures of around 1,473-1,673 kelvin. Our approach to liquid-metal pumping is enabled by the use of ceramics for the mechanical and sealing components, but owing to the brittle nature of ceramics their use requires careful engineering. Our set-up enables effective heat transfer using a liquid at previously unattainable temperatures, and could be used for thermal storage and transport, electric power production, and chemical or materials processing.

Solar Refrigerator/Freezers For Vaccines

NASA Technical Reports Server (NTRS)

Ratajczak, Anthony F.

1988-01-01

Report presents results of field tests of solar-cell-powered refrigerator/freezers for vaccines. Covers following topics: explanation of project; descriptions of refrigerator/freezer systems; account of installation experiences; performance data for 22 systems for which field-test data reported; summary of operational reliability; comments of users of some systems tested; and recommendations for design and future use. Photovoltaic systems store vaccines in remote regions where powerlines unavailable.

Magnetic moment of solar plasma and the Kelvin force: -The driving force of plasma up-flow -

NASA Astrophysics Data System (ADS)

Shibasaki, Kiyoto

2017-04-01

Thermal plasma in the solar atmosphere is magnetized (diamagnetic). The magnetic moment does not disappear by collisions because complete gyration is not a necessary condition to have magnetic moment. Magnetized fluid is subjected to Kelvin force in non-uniform magnetic field. Generally, magnetic field strength decreases upwards in the solar atmosphere, hence the Kelvin force is directed upwards along the field. This force is not included in the fluid treatment of MHD. By adding the Kelvin force to the MHD equation of motion, we can expect temperature dependent plasma flows along the field which are reported by many observations. The temperature dependence of the flow speed is explained by temperature dependence of magnetic moment. From the observed parameters, we can infer physical parameters in the solar atmosphere such as scale length of the magnetic field strength and the friction force acting on the flowing plasma. In case of closed magnetic field lines, loop-top concentration of hot plasma is expected which is frequently observed.

Evaluation of Alternative Refrigerants for Mini-Split Air Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Shrestha, Som S

The phase-out of hydrochlorofluorocarbons (HCFC) refrigerants in developing countries is currently underway according to the Montreal Protocol. R-22 is one of the most commonly used HCFCs in the developing nations. It is extremely well suited for air conditioning and refrigeration (AC&R) in high ambient temperature environments. Non-Article 5 countries have already gone through the phase-out of HCFCs and settled on using R-410A as the refrigerant of choice for AC applications. Previous studies have shown that R-410A results in significant capacity and performance degradation at higher ambient temperature conditions. As such, there is a growing concern on finding alternative refrigerants tomore » R-22 that would have zero ODP, lower GWP, and at the same time maintain acceptable performance at higher ambient temperatures. Furthermore, the developed world s transition through higher global warming potential (GWP) refrigerants like HFC and HFC blends resulted in significant direct CO2 equivalent emissions. It is imperative to develop a bridge for developing nations to avoid the transition from HCFC to HFC and then from HFC to alternative lower GWP refrigerants. This paper summarizes data from an experimental campaign on alternative refrigerant evaluation for R-22 and R-410A substitutes for mini-split air conditioners designed for high ambient environments. The experimental evaluation was performed according to ANSI/ASHRAE Standard 37 and the performance was rated at test conditions specified by ANSI/AHRI 210-240 and ISO 5151. Additional tests were conducted at outdoor ambient temperatures of 52 C (125.6 F) and 55 C (131 F) to evaluate their performance at high ambient conditions. Alternative refrigerants, some of which are proprietary, included R-444B, DR-3, N-20b, ARM-20b, R-290, and DR-93 as alternatives to R-22 and R-32, DR-55, L41-2, ARM-71A, and HPR-2A as alternatives to R-410A. The units performances were first verified using the baseline refrigerant and then

Shuttle Kit Freezer Refrigeration Unit Conceptual Design

NASA Technical Reports Server (NTRS)

Copeland, R. J.

1975-01-01

The refrigerated food/medical sample storage compartment as a kit to the space shuttle orbiter is examined. To maintain the -10 F in the freezer kit, an active refrigeration unit is required, and an air cooled Stirling Cycle refrigerator was selected. The freezer kit contains two subsystems, the refrigeration unit, and the storage volume. The freezer must provide two basic capabilities in one unit. One requirement is to store 215 lbs of food which is consumed in a 30-day period by 7 people. The other requirement is to store 128.3 lbs of medical samples consisting of both urine and feces. The unit can be mounted on the lower deck of the shuttle cabin, and will occupy four standard payload module compartments on the forward bulkhead. The freezer contains four storage compartments.

Kelvin-Helmholtz instability of the Dirac fluid of charge carriers on graphene

NASA Astrophysics Data System (ADS)

Coelho, Rodrigo C. V.; Mendoza, Miller; Doria, Mauro M.; Herrmann, Hans J.

2017-11-01

We provide numerical evidence that a Kelvin-Helmholtz instability occurs in the Dirac fluid of electrons in graphene and can be detected in current experiments. This instability appears for electrons in the viscous regime passing though a micrometer-scale obstacle and affects measurements on the time scale of nanoseconds. A possible realization with a needle-shaped obstacle is proposed to produce and detect this instability by measuring the electric potential difference between contact points located before and after the obstacle. We also show that, for our setup, the Kelvin-Helmholtz instability leads to the formation of whirlpools similar to the ones reported in Bandurin et al. [Science 351, 1055 (2016), 10.1126/science.aad0201]. To perform the simulations, we develop a lattice Boltzmann method able to recover the full dissipation in a fluid of massless particles.

Improving NIS Tunnel Junction Refrigerators: Modeling, Materials, and Traps

NASA Astrophysics Data System (ADS)

O'Neil, Galen Cascade

This thesis presents a systematic study of electron cooling with Normal-metal/insulator/superconductor (NIS) tunnel junctions. NIS refrigerators have an exciting potential to simplify 100 mK and 10 mK cryogenics. Rather than using an expensive dilution refrigerator, researchers will be able to use much simpler cryogenics to reach 300 mK and supplement them with mass fabricated thin-film NIS refrigerators to reach 100 mK and below. The mechanism enabling NIS refrigeration is energy selective tunneling. Due to the gap in the superconducting density of states, only hot electrons tunnel from the normal-metal. Power is removed from the normal-metal, that same power and the larger IV power are both deposited in the superconductor. NIS refrigerators often cool less than theory predicts because of the power deposited in the superconductor returns to the normal-metal. When the superconductor temperature is raised, or athermal phonons due to quasiparticle recombination are absorbed in the normal-metal, refrigerator performance will be reduced. I studied the quasiparticle excitations in superconductors to develop the most complete thermal model of NIS refrigerators to date. I introduced overlayer quasiparticle traps, a new method for heatsinking the superconductor. I present measurements on NIS refrigerators with and without quasiparticle traps, to determine their effectiveness. This includes an NIS refrigerator that cools from 300 mK to 115 mK or lower, a large improvement over previous designs. I also looked into reducing the power deposited in the superconductor, by choosing the transition temperature of the superconductor based upon the NIS refrigerator launch temperature. I performed a detailed study of the density of states of superconducting AlMn alloys, demonstrating that Mn impurities behave non-magnetically in Al due to resonant scattering. The density of states remains BCS-like, but my measurements show that the deviations from a BCS density of states harm cooling

Hydride compressor

DOEpatents

Powell, James R.; Salzano, Francis J.

1978-01-01

Method of producing high energy pressurized gas working fluid power from a low energy, low temperature heat source, wherein the compression energy is gained by using the low energy heat source to desorb hydrogen gas from a metal hydride bed and the desorbed hydrogen for producing power is recycled to the bed, where it is re-adsorbed, with the recycling being powered by the low energy heat source. In one embodiment, the adsorption-desorption cycle provides a chemical compressor that is powered by the low energy heat source, and the compressor is connected to a regenerative gas turbine having a high energy, high temperature heat source with the recycling being powered by the low energy heat source.

Mixed Refrigerants for a Glass Capillary Micro Cryogenic Cooler

DTIC Science & Technology

2010-08-01

refrigerant has the largest ðDhTÞmin 1.35 kJ/mol. To deliver 15 mW of gross refrigeration power, JT cryocoolers using mixed refrigerants only require 1.6...higher than 75 K. Pressure drop in heat exchangers can cause refrigeration loss in cryocooler systems. The minimum enthalpy difference and hence...micro- cryocoolers . They solved it by making the returning flow laminar through re-design- ing micro channels. Fig. 4 shows the relationship between the

Fault detection and diagnosis for refrigerator from compressor sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identifiedmore » if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.« less

Time-Temperature Profiling of United Kingdom Consumers' Domestic Refrigerators.

PubMed

Evans, Ellen W; Redmond, Elizabeth C

2016-12-01

Increased consumer demand for convenience and ready-to-eat food, along with changes to consumer food purchase and storage practices, have resulted in an increased reliance on refrigeration to maximize food safety. Previous research suggests that many domestic refrigerators operate at temperatures exceeding recommendations; however, the results of several studies were determined by means of one temperature data point, which, given temperature fluctuation, may not be a true indicator of actual continual operating temperatures. Data detailing actual operating temperatures and the effects of consumer practices on temperatures are limited. This study has collated the time-temperature profiles of domestic refrigerators in consumer kitchens (n = 43) over 6.5 days with concurrent self-reported refrigerator usage. Overall, the findings established a significant difference (P < 0.05) between one-off temperature (the recording of one temperature data point) and mean operating temperature. No refrigerator operated at ≤5.0°C for the entire duration of the study. Mean temperatures exceeding 5.0°C were recorded in the majority (91%) of refrigerators. No significant associations or differences were determined for temperature profiles and demographics, including household size, or refrigerator characteristics (age, type, loading, and location). A positive correlation (P < 0.05) between room temperature and refrigerator temperature was determined. Reported door opening frequency correlated with temperature fluctuation (P < 0.05). Thermometer usage was determined to be infrequent. Cumulatively, research findings have established that the majority of domestic refrigerators in consumer homes operate at potentially unsafe temperatures and that this is influenced by consumer usage. The findings from this study may be utilized to inform the development of shelf-life testing based on realistic domestic storage conditions. Furthermore, the data can inform the development of future

Hydrogen storage and evolution catalysed by metal hydride complexes.

PubMed

Fukuzumi, Shunichi; Suenobu, Tomoyoshi

2013-01-07

The storage and evolution of hydrogen are catalysed by appropriate metal hydride complexes. Hydrogenation of carbon dioxide by hydrogen is catalysed by a [C,N] cyclometalated organoiridium complex, [Ir(III)(Cp*)(4-(1H-pyrazol-1-yl-κN(2))benzoic acid-κC(3))(OH(2))](2)SO(4) [Ir-OH(2)](2)SO(4), under atmospheric pressure of H(2) and CO(2) in weakly basic water (pH 7.5) at room temperature. The reverse reaction, i.e., hydrogen evolution from formate, is also catalysed by [Ir-OH(2)](+) in acidic water (pH 2.8) at room temperature. Thus, interconversion between hydrogen and formic acid in water at ambient temperature and pressure has been achieved by using [Ir-OH(2)](+) as an efficient catalyst in both directions depending on pH. The Ir complex [Ir-OH(2)](+) also catalyses regioselective hydrogenation of the oxidised form of β-nicotinamide adenine dinucleotide (NAD(+)) to produce the 1,4-reduced form (NADH) under atmospheric pressure of H(2) at room temperature in weakly basic water. In weakly acidic water, the complex [Ir-OH(2)](+) also catalyses the reverse reaction, i.e., hydrogen evolution from NADH to produce NAD(+) at room temperature. Thus, interconversion between NADH (and H(+)) and NAD(+) (and H(2)) has also been achieved by using [Ir-OH(2)](+) as an efficient catalyst and by changing pH. The iridium hydride complex formed by the reduction of [Ir-OH(2)](+) by H(2) and NADH is responsible for the hydrogen evolution. Photoirradiation (λ > 330 nm) of an aqueous solution of the Ir-hydride complex produced by the reduction of [Ir-OH(2)](+) with alcohols resulted in the quantitative conversion to a unique [C,C] cyclometalated Ir-hydride complex, which can catalyse hydrogen evolution from alcohols in a basic aqueous solution (pH 11.9). The catalytic mechanisms of the hydrogen storage and evolution are discussed by focusing on the reactivity of Ir-hydride complexes.

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

PubMed Central

Takagi, Shigeyuki; Iijima, Yuki; Sato, Toyoto; Saitoh, Hiroyuki; Ikeda, Kazutaka; Otomo, Toshiya; Miwa, Kazutoshi; Ikeshoji, Tamio; Orimo, Shin-ichi

2017-01-01

Ninefold coordination of hydrogen is very rare, and has been observed in two different hydride complexes comprising rhenium and technetium. Herein, based on a theoretical/experimental approach, we present evidence for the formation of ninefold H- coordination hydride complexes of molybdenum ([MoH9]3−), tungsten ([WH9]3−), niobium ([NbH9]4−) and tantalum ([TaH9]4−) in novel complex transition-metal hydrides, Li5MoH11, Li5WH11, Li6NbH11 and Li6TaH11, respectively. All of the synthesized materials are insulated with band gaps of approximately 4 eV, but contain a sufficient amount of hydrogen to cause the H 1s-derived states to reach the Fermi level. Such hydrogen-rich materials might be of interest for high-critical-temperature superconductivity if the gaps close under compression. Furthermore, the hydride complexes exhibit significant rotational motions associated with anharmonic librations at room temperature, which are often discussed in relation to the translational diffusion of cations in alkali-metal dodecahydro-closo-dodecaborates and strongly point to the emergence of a fast lithium conduction even at room temperature. PMID:28287143

El Ni?o Pumping Up, Warm Kelvin Wave Surges Toward South America

NASA Image and Video Library

2009-11-12

ElNi?o is experiencing a late-fall resurgence. Sea-level height data from the NASA/European Ocean Surface Topography Mission/Jason-2 oceanography satellite show the equatorial Pacific has triggered a wave of warm water, known as a Kelvin wave.

El Niño Surges; Warm Kelvin Wave Headed for South America

NASA Image and Video Library

2009-12-17

The most recent sea-level height data from the NASA/European Ocean Surface Topography Mission/Jason-2 oceanography satellite show the continued eastward progression of a strong wave of warm water, known as a Kelvin wave, now approaching South America.

Hydride Microstructure at the Metal-Oxide Interface of Zircaloy-4 from H.B. Robinson Nuclear Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cinbiz, Mahmut N; Edmondson, Philip D; Terrani, Kurt A

2017-01-01

This study investigates the hydride rim microstructure at the metal-oxide interface of Zircaloy-4 cladding segment removed from H.B. Robinson Nuclear Reactor by utilizing high resolution electron microscopy techniques with energy dispersive x-ray spectroscopy at Oak Ridge National Laboratory under the NSUF Rapid Turnout Experiment program. A complex stacking and orientation of hydride platelets has been observed below the sub-oxide layer. Furthermore, radial hydride platelets have been observed. EDS signals of both Fe and Cr has been reduced within hydrides whereas EDS signal of Sn is unaffected.

An experimental study for a miniature Stirling refrigerator

NASA Technical Reports Server (NTRS)

Li, S.; Chen, G.; Huang, Z.; Zhang, F.; Cui, C.; Li, J.

1985-01-01

Experimental results of a miniature two-stage Stirling cryocooler are introduced. The influence of filling gas pressure and refrigeration temperature on the refrigerating capacity along with the relationship between parameters was measured. The valley pressure corresponding to the lowest refrigeration temperature and the cooldown time versus operating pressure are discussed. The coefficient of performance and thermodynamic efficiency of the cryocooler are calculated based on experimental data.

Assessing the role of the Kelvin-Helmholtz instability at the QCD cosmological transition

NASA Astrophysics Data System (ADS)

Mourão Roque, V. R. C.; Lugones, G.

2018-03-01

We performed numerical simulations with the PLUTO code in order to analyze the non-linear behavior of the Kelvin-Helmholtz instability in non-magnetized relativistic fluids. The relevance of the instability at the cosmological QCD phase transition was explored using an equation of state based on lattice QCD results with the addition of leptons. The results of the simulations were compared with the theoretical predictions of the linearized theory. For small Mach numbers up to Ms ~ 0.1 we find that both results are in good agreement. However, for higher Mach numbers, non-linear effects are significant. In particular, many initial conditions that look stable according to the linear analysis are shown to be unstable according to the full calculation. Since according to lattice calculations the cosmological QCD transition is a smooth crossover, violent fluid motions are not expected. Thus, in order to assess the role of the Kelvin-Helmholtz instability at the QCD epoch, we focus on simulations with low shear velocity and use monochromatic as well as random perturbations to trigger the instability. We find that the Kelvin-Helmholtz instability can strongly amplify turbulence in the primordial plasma and as a consequence it may increase the amount of primordial gravitational radiation. Such turbulence may be relevant for the evolution of the Universe at later stages and may have an impact in the stochastic gravitational wave background.

Oxidation kinetics of hydride-bearing uranium metal corrosion products

NASA Astrophysics Data System (ADS)

Totemeier, Terry C.; Pahl, Robert G.; Frank, Steven M.

The oxidation behavior of hydride-bearing uranium metal corrosion products from Zero Power Physics Reactor (ZPPR) fuel plates was studied using thermo-gravimetric analysis (TGA) in environments of Ar-4%O 2, Ar-9%O 2, and Ar-20%O 2. Ignition of corrosion product samples from two moderately corroded plates was observed between 125°C and 150°C in all environments. The rate of oxidation above the ignition temperature was found to be dependent only on the net flow rate of oxygen in the reacting gas. Due to the higher net oxygen flow rate, burning rates increased with increasing oxygen concentration. Oxidation rates below the ignition temperature were much slower and decreased with increasing test time. The hydride contents of the TGA samples from the two moderately corroded plates, determined from the total weight gain achieved during burning, were 47-61 wt% and 29-39 wt%. Samples from a lightly corroded plate were not reactive; X-ray diffraction (XRD) confirmed that they contained little hydride.

Defrost Temperature Termination in Supermarket Refrigeration Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, Brian A; Sharma, Vishaldeep

2011-11-01

The objective of this project was to determine the potential energy savings associated with implementing demand defrost strategies to defrost supermarket refrigerated display case evaporators, as compared to the widely accepted current practice of controlling display case defrost cycles with a preset timer. The defrost heater energy use of several representative display case types was evaluated. In addition, demand defrost strategies for refrigerated display cases as well as those used in residential refrigerator/freezers were evaluated. Furthermore, it is anticipated that future work will include identifying a preferred defrost strategy, with input from Retail Energy Alliance members. Based on this strategy,more » a demand defrost system will be designed which is suitable for supermarket refrigerated display cases. Limited field testing of the preferred defrost strategy will be performed in a supermarket environment.« less

Helium refrigeration systems for super-conducting accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganni, V.

Many of the present day accelerators are based on superconducting technology which requires 4.5-K or 2-K helium refrigeration systems. These systems utilize superconducting radio frequency (SRF) cavities and/or superconducting magnets which are packaged into vacuum vessels known as cryo-modules (CM’s). Many of the present day accelerators are optimized to operate primarily at around 2-K, requiring specialized helium refrigeration systems which are cost intensive to produce and to operate. Some of the cryogenic refrigeration system design considerations for these challenging applications are discussed.

Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant

DOEpatents

Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN

2006-02-07

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.

Assessment of Environmentally Friendly Refrigerants for Window Air Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Pradeep; Shen, Bo

This paper presents technical assessment of environmentally friendly refrigerants for window air conditioners that currently use refrigerant R410A for residential and commercial applications. The alternative refrigerants that are studied for its replacement include R32, R600a, R290, R1234yf, R1234ze and a mixture of R32 (90% molar concentration) and R125 (10% molar concentration). Baseline experiments were performed on a window unit charged with R410A. The ORNL Heat Pump Design Model was calibrated with the baseline data and was used to assess the comparative performance of the WAC with alternative refrigerants. The paper discusses the advantages and disadvantages of each refrigerants and theirmore » suitability for window air conditioners.« less

EVALUATION OF REFRIGERANT FROM MOBILE AIR CONDITIONERS

EPA Science Inventory

The report gives results of a project to provide a scientific basis for choosing a reasonable standard of purity for recycled chlorofluorocarbon (CFC) refrigerant in operating automobile air conditioners. The quality of refrigerant from air conditioners in automobiles of differen...

Pyrophoric behaviour of uranium hydride and uranium powders

NASA Astrophysics Data System (ADS)

Le Guyadec, F.; Génin, X.; Bayle, J. P.; Dugne, O.; Duhart-Barone, A.; Ablitzer, C.

2010-01-01

Thermal stability and spontaneous ignition conditions of uranium hydride and uranium metal fine powders have been studied and observed in an original and dedicated experimental device placed inside a glove box under flowing pure argon. Pure uranium hydride powder with low amount of oxide (<0.5 wt.%) was obtained by heat treatment at low temperature in flowing Ar/5%H2. Pure uranium powder was obtained by dehydration in flowing pure argon. Those fine powders showed spontaneous ignition at room temperature in air. An in situ CCD-camera displayed ignition associated with powder temperature measurement. Characterization of powders before and after ignition was performed by XRD measurements and SEM observations. Oxidation mechanisms are proposed.

Magnetic Reconnection and the Kelvin-Helmholtz Instability

NASA Astrophysics Data System (ADS)

Knoll, D. A.; Chacon, L.; Brackbill, J. U.; Lapenta, G.

2002-11-01

Results are presented from a continuing study of magnetic reconnection caused by the evolution of a Kelvin-Helmholtz instability. To date we have studied 3-D compressible, subsonic and and sub-Alfvenic flow, with differential rotation (a gradient in vorticity parallel to the initial magnetic field) [1,2], as well as 2-D incompressible super-Alfvenic flow [3]. In both cases localized transient reconnection is observed on the Kelvin-Helmholtz time scale, and results indicate that the observed reconnection rate is insensitive to resistivity. In the present study we extend both the 2-D and the 3-D results found in [1,2,3]. In the extension of the 2-D work we focus on the fundamental differences in the nonlinear evolution of a low S simulation (S = 200) and a higher S simulation (S = 10,000). In the 3-D work we study the effects of a density discontinuity (present in [1] and not in [2]), along with study the effects of initial curved field lines in the absence of differential rotation. This basic plasma physics problem has possible application to dayside magnetosphere reconnection as a theoretical model for flux transfer events [1]. The general problem also has possible application to solar physics as it could provide a trigger mechanism for some class of coronal mass ejections. Both applications will be briefly discussed. [1] J.U. Brackbill and D.A. Knoll, Phys. Rev. Lett., vol. 86 (2001). [2] D.A. Knoll and J.U. Brackbill, Physics of Plasmas, to appear (2002) [3] D.A. Knoll and L. Chacon, Phys. Rev. Lett., vol. 88 (2002).

Epitaxial growth of pentacene on alkali halide surfaces studied by Kelvin probe force microscopy.

PubMed

Neff, Julia L; Milde, Peter; León, Carmen Pérez; Kundrat, Matthew D; Eng, Lukas M; Jacob, Christoph R; Hoffmann-Vogel, Regina

2014-04-22

In the field of molecular electronics, thin films of molecules adsorbed on insulating surfaces are used as the functional building blocks of electronic devices. Control of the structural and electronic properties of the thin films is required for reliably operating devices. Here, noncontact atomic force and Kelvin probe force microscopies have been used to investigate the growth and electrostatic landscape of pentacene on KBr(001) and KCl(001) surfaces. We have found that, together with molecular islands of upright standing pentacene, a new phase of tilted molecules appears near step edges on KBr. Local contact potential differences (LCPD) have been studied with both Kelvin experiments and density functional theory calculations. Our images reveal that differently oriented molecules display different LCPD and that their value is independent of the number of molecular layers. These results point to the formation of an interface dipole, which may be explained by a partial charge transfer from the pentacene to the surface. Moreover, the monitoring of the evolution of the pentacene islands shows that they are strongly affected by dewetting: Multilayers build up at the expense of monolayers, and in the Kelvin images, previously unknown line defects appear, which reveal the epitaxial growth of pentacene crystals.

Condensation of nano-refrigerant inside a horizontal tube

NASA Astrophysics Data System (ADS)

Darzi, Milad; Sadoughi, M. K.; Sheikholeslami, M.

2018-05-01

In this paper, condensing pressure drop of refrigerant-based nanofluid inside a tube is studied. Isobutene was selected as the base fluid while CuO nanoparticles were utilized to prepare nano-refrigerant. However, for the feasibility of nanoparticle dispersion into the refrigerant, Polyester oil (POE) was utilized as lubricant oil and added to the pure refrigerant by 1% mass fraction. Various values of mass flux, vapor quality, concentration of nanoparticle are investigated. Results indicate that adding nanoparticles leads to enhance frictional pressure drop. Nanoparticles caused larger pressure drop penalty at relatively lower vapor qualities which may be attributed to the existing condensation flow pattern such that annular flow is less influenced by nanoparticles compared to intermittent flow regime.

Pulsed laser deposition of air-sensitive hydride epitaxial thin films: LiH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oguchi, Hiroyuki, E-mail: oguchi@nanosys.mech.tohoku.ac.jp; Micro System Integration Center; Isobe, Shigehito

2015-09-01

We report on the epitaxial thin film growth of an air-sensitive hydride, lithium hydride (LiH), using pulsed laser deposition (PLD). We first synthesized a dense LiH target, which is key for PLD growth of high-quality hydride films. Then, we obtained epitaxial thin films of [100]-oriented LiH on a MgO(100) substrate at 250 °C under a hydrogen pressure of 1.3 × 10{sup −2} Pa. Atomic force microscopy revealed that the film demonstrates a Stranski-Krastanov growth mode and that the film with a thickness of ∼10 nm has a good surface flatness, with root-mean-square roughness R{sub RMS} of ∼0.4 nm.

Combined on-board hydride slurry storage and reactor system and process for hydrogen-powered vehicles and devices

DOEpatents

Brooks, Kriston P; Holladay, Jamelyn D; Simmons, Kevin L; Herling, Darrell R

2014-11-18

An on-board hydride storage system and process are described. The system includes a slurry storage system that includes a slurry reactor and a variable concentration slurry. In one preferred configuration, the storage system stores a slurry containing a hydride storage material in a carrier fluid at a first concentration of hydride solids. The slurry reactor receives the slurry containing a second concentration of the hydride storage material and releases hydrogen as a fuel to hydrogen-power devices and vehicles.

Calculated Hydride Donor Abilities of Five-Coordinate Transition Metal Hydrides [HM(diphosphine)2] (+) (M = Ni, Pd, Pt) as a Function of the Bite Angle and Twist Angle of Diphosphine Ligands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nimlos, Mark R.; Chang, Christopher H.; Curtis, Calvin J.

2008-07-07

Density functional theory (BLYP and B3LYP) and the polarized continuum model (PCM-UA0) for solvation have been used to investigate the effect of bite angle (P-M-P) of diphosphine ligands and the dihedral or twist angle between diphosphine ligands on the hydride donor abilities of Ni, Pd, and Pt [HM(diphosphine)2]+ complexes. It is found that an increased bite angle for a given transition metal atom results in poorer hydride donor abilities. However, hydride donor abilities for these complexes also decrease as the size of the alkyl side groups on the phosphorus atom increase (Et > Me > H) and with the lengthmore » of the metal phosphorus bond (Ni > Pd = Pt). These trends correlate with an increase in the twist angle between the two diphosphine ligands, which increases from 0° for a square-planar configuration to 90° for a tetrahedral geometry. Shorter M-P bonds, larger substituents on the diphosphine ligands, and larger bite angles all result in increased steric interactions between diphosphine ligands and larger dihedral or twist angles between the diphosphine ligands. The twist angle correlates much more strongly with hydride donor abilities than do bite angles alone. As the twist angle increases, the hydride donor ability decreases in a linear fashion. A frontier orbital analysis has been carried out, and it is shown that the hydride donor ability of [HM(diphosphine)2]+ complexes is largely determined by the energy of the lowest unoccupied molecular orbital of the corresponding [M(diphosphine)2]2+ complex. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.« less

Calculated Hydride Donor Abilities of Five-Coordinate Transition Metal Hydrides [HM(diphosphine)2]+ (M = Ni, Pd, Pt) as a Function of the Bite Angle and Twist Angle of Diphosphine Ligands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nimlos, Mark; Chang, Christopher H.; Curtis, Calvin J.

2008-06-23

Density functional theory (BLYP and B3LYP) and the polarized continuum model (PCM-UA0) for solvation have been used to investigate the effect of bite angle (P-M-P) of diphosphine ligands and the dihedral or twist angle between diphosphine ligands on the hydride donor abilities of Ni, Pd, and Pt [HM(diphosphine)2]+ complexes. It is found that an increased bite angle for a given transition metal atom results in poorer hydride donor abilities. However, hydride donor abilities for these complexes also decrease as the size of the alkyl side groups on the phosphorus atom increase (Et > Me > H) and with the lengthmore » of the metal phosphorus bond (Ni > Pd = Pt). These trends correlate with an increase in the twist angle between the two diphosphine ligands, which increases from 0° for a square-planar configuration to 90° for a tetrahedral geometry. Shorter M-P bonds, larger substituents on the diphosphine ligands, and larger bite angles all result in increased steric interactions between diphosphine ligands and larger dihedral or twist angles between the diphosphine ligands. The twist angle correlates much more strongly with hydride donor abilities than do bite angles alone. As the twist angle increases, the hydride donor ability decreases in a linear fashion. A frontier orbital analysis has been carried out, and it is shown that the hydride donor ability of [HM(diphosphine)2]+ complexes is largely determined by the energy of the lowest unoccupied molecular orbital of the corresponding [M(diphosphine)2]2+ complex. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.« less

Supermarket refrigeration assessment for the Commonwealth Electric Company

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsaros, T.L.; Walker, D.H.

The Commonwealth Electric Company (COM/Electric) has initiated an incentive program to promote electric energy conservation within its service territory. The Electric Power Research Institute (EPRI) has assisted COM/Electric in assessing the impact on the utility and its customers of implementing energy efficient supermarket refrigeration in retrofit applications. The primary task of this assessment was to contact the supermarket chains and refrigeration contractors and suppliers in the COM/Electric service territory to determine the type of refrigeration employed and standard or novel retrofit equipment implemented in supermarkets. With this information, estimates were made of the potential energy savings that COM/Electric and themore » supermarkets could realize if supermarkets were retrofitted with energy efficient refrigeration equipment. It was determined that the refrigerated display case features offering the greatest potential for savings through retrofit installations include doors for medium temperature multideck cases, high-efficiency fan motors, anti-sweat heater controls, and vinyl strip curtains for walk-in coolers. The retrofit components associated with the compressor machine room that offer the greatest potential for savings include the use of low heat pressure control, hot gas defrost, and external liquid-suction heat exchangers and remote evaporative subcoolers for low temperature refrigeration. 6 refs., 14 figs., 26 tabs.« less

Investigation of long term stability in metal hydrides

NASA Technical Reports Server (NTRS)

Marmaro, Roger W.; Lynch, Franklin E.; Chandra, Dhanesh; Lambert, Steve; Sharma, Archana

1991-01-01

It is apparent from the literature and the results of this study that cyclic degradation of AB(5) type metal hydrides varies widely according to the details of how the specimens are cycled. The Rapid Cycle Apparatus (RCA) used produced less degradation in 5000 to 10000 cycles than earlier work with a Slow Cycle Apparatus (SCA) produced in 1500 cycles. Evidence is presented that the 453 K (356 F) Thermal Aging (TA) time spent in the saturated condition causes hydride degradation. But increasing the cooling (saturation) period in the RCA did not greatly increase the rate of degradation. It appears that TA type degradation is secondary at low temperatures to another degradation mechanism. If rapid cycles are less damaging than slow cycles when the saturation time is equal, the rate of hydriding/dehydriding may be an important factor. The peak temperatures in the RCA were about 30 C lower than the SCA. The difference in peak cycle temperatures (125 C in the SCA, 95 C in RCA) cannot explain the differences in degradation. TA type degradation is similar to cyclic degradation in that nickel peaks and line broadening are observed in X ray diffraction patterns after either form of degradation.

Advances in refrigeration and heat transfer engineering

DOE PAGES

Bansal, Pradeep; Cremaschi, Prof. Lorenzo

2015-05-13

This special edition of Science and Technology for the Built Environment (STBE) presents selected high quality papers that were presented at the 15th International Refrigeration and Air Conditioning Conference held at Purdue University during July 14-17 2014. All papers went through the additional review before being finally accepted for publication in this special issue of Science and Technology and the Built Environment. Altogether 20 papers made to this special issue that cover a wide range of topics, including advancements in alternative refrigerants, heat exchangers/heat transfer, nano-fluids, systems design and optimization and modeling approaches. Although CO 2 may perhaps have beenmore » the most researched and popular refrigerant in the past decade, R32 is being seriously considered lately as an alternative and environmentally friendly refrigerant for small systems due to its low Global Warming Potential (GWP).« less

Advances in refrigeration and heat transfer engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Pradeep; Cremaschi, Prof. Lorenzo

This special edition of Science and Technology for the Built Environment (STBE) presents selected high quality papers that were presented at the 15th International Refrigeration and Air Conditioning Conference held at Purdue University during July 14-17 2014. All papers went through the additional review before being finally accepted for publication in this special issue of Science and Technology and the Built Environment. Altogether 20 papers made to this special issue that cover a wide range of topics, including advancements in alternative refrigerants, heat exchangers/heat transfer, nano-fluids, systems design and optimization and modeling approaches. Although CO 2 may perhaps have beenmore » the most researched and popular refrigerant in the past decade, R32 is being seriously considered lately as an alternative and environmentally friendly refrigerant for small systems due to its low Global Warming Potential (GWP).« less

ARTI Refrigerant Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1992-11-09

The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air- conditioning and refrigeration equipment. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R- 717 (ammonia), ethers, and others as well as azeotropic and zeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents on compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerantmore » circuits. A computerized version is available that includes retrieval software.« less

Observations of Equatorial Kelvin Waves and their Convective Coupling with the Atmosphere/Ocean Surface Layer

NASA Astrophysics Data System (ADS)

Conry, Patrick; Fernando, H. J. S.; Leo, Laura; Blomquist, Byron; Amelie, Vincent; Lalande, Nelson; Creegan, Ed; Hocut, Chris; MacCall, Ben; Wang, Yansen; Jinadasa, S. U. P.; Wang, Chien; Yeo, Lik-Khian

2016-11-01

Intraseasonal disturbances with their genesis in the equatorial Indian Ocean (IO) are an important component of global climate. The disturbances, which include Madden-Julian Oscillation and equatorial Kelvin and Rossby waves in the atmosphere and ocean, carry energy which affects El Niño, cyclogenesis, and monsoons. A recent field experiment in IO (ASIRI-RAWI) observed disturbances at three sites across IO with arrays of instruments probing from surface layer to lower stratosphere. During the field campaign the most pronounced planetary-scale disturbances were Kelvin waves in tropical tropopause layer. In Seychelles, quasi-biweekly westerly wind bursts were documented and linked to the Kelvin waves aloft, which breakdown in the upper troposphere due to internal shear instabilities. Convective coupling between waves' phase in upper troposphere and surface initiates rapid (turbulent) vertical transport and resultant wind bursts at surface. Such phenomena reveal linkages between planetary-scale waves and small-scale turbulence in the surface layer that can affect air-sea property exchanges and should be parameterized in atmosphere-ocean general circulation models. Funded by ONR Grants N00014-14-1-0279 and N00014-13-1-0199.