Sample records for hfc refrigerant mixtures

  1. Heat Transfer and Pressure Drop for Flow Boiling of Non-Azeotropic Refrigerant Mixtures of HFC-32/HFC-125/HFC-134a and HFC-32/HFC-134a in Horizontal Tubes

    NASA Astrophysics Data System (ADS)

    Mori, Hideo; Yoshida, Suguru; Ohishi, Katsumi

    Experiments were performed on heat transfer and pressure drop for flow boiling of two non-azeotropic refrigerant mixtures of HFC-32/HFC-125/HFC-134a and HFC-32/HFC-134a at respectively certain compositions,which are expected to be alternatives to HCFC-22,in horizontal smooth and internally,spirally grooved tubes. Almost the same local heat transfer coefficients were obtained for both the mixtures in each tube. In the smooth tube,in the region where nucleate boiling contributes substantially to the heat transfer,the heat transfer coefficients for the mixtures were reduced down to about two-thirds of the value for HCFC-22,due to the effect of a mass transfer resistance on the heat transfer,while they were approximately equal to those for HCFC-22 in the forced convection dominated region. With the grooved tube,the heat transfer was enhanced over the smooth tube,but the enhancement was smaller than that for HCFC-22. In both the tubes,frictional pressure drops for the binary mixture were generally a few to 20 percent higher than those for the ternary mixture and the pure refrigerant,corresponding to the difference in the vapor density.

  2. An Assessment of Thermodynamic Models for HFC Refrigerant Mixtures Through the Critical-Point Calculation

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

    2008-08-01

    An assessment of thermodynamic models for HFC refrigerant mixtures based on Helmholtz energy equations of state was made through critical-point calculations for ternary and quaternary mixtures. The calculations were performed using critical-point criteria expressed in terms of the Helmholtz free energy. For three ternary mixtures: difluoromethane (R-32) + pentafluoroethane (R-125) + 1,1,1,2-tetrafluoroethane (R-134a), R-125 + R-134a + 1,1,1-trifluoroethane (R-143a), and carbon dioxide (CO2) + R-32 + R-134a, and one quaternary mixture, R-32 + R-125 + R-134a + R-143a, calculated critical points were compared with experimental values, and the capability of the mixture models for representing the critical behavior was discussed.

  3. Formation Conditions of Clathrates Between HFC Alternative Refrigerants and Water

    NASA Astrophysics Data System (ADS)

    Akiya, T.; Shimazaki, T.; Oowa, M.; Matsuo, M.; Yoshida, Y.

    1999-11-01

    There are two promising candidates as alternative refrigerants for air-conditioners and heat pumps. The first is R407C, which is composed of HFC-32 (23 mass%), HFC-125 (25 mass%), and HFC-134a (52 mass%). The second is R410A, which is composed of HFC-32 (50 mass%) and HFC-125 (50 mass%). In this study, formation conditions of clathrate compounds between water and HFC alternative refrigerants such as HFC-32, HFC-125, HFC-134a, and their mixtures, R407C and R410A, were investigated. Phase diagrams of clathrates of these HFC alternative refrigerants and their mixtures were determined. From the phase diagrams, the critical decomposition temperature and the critical decomposition pressure were determined. The relationship between the critical decomposition points for the clathrates of HFC-32, HFC-125, HFC-134a, R410A, and R407C were studied. It is found that R407C and R410A form clathrate compounds with water under the evaporating temperature condition in the refrigeration cycle of air-conditioners and heat pumps.

  4. 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...

  5. Two-Phase Flow of Two HFC Refrigerant Mixtures Through Short Tube Orifices, Draft Final Report 

    E-print Network

    Payne, W. V.; O'Neal, D. L.

    1994-01-01

    for the ternary zeotrope and binary near-azeotrope were calculated based upon thermodynamic property data supplied by the refrigerant manufacturers. EPA Task 1 Drafl Report, Page No. 16 Table 2.2: Description of the Data Acquisition Sensor Channels. Channel... temperatures 95?F (35.0?C), 110?F (43.3"C), and 125?F (51.7"C) were selected for both the ternary and binary refrigerants. The corresponding upstream saturation pressures for the ternary mixture were 22 1 psia (1524.kPa), 27 1 psia (1870 kPa), and 329 psia...

  6. Formation Conditions of Clathrates Between HFC Alternative Refrigerants and Water

    Microsoft Academic Search

    T. Akiya; T. Shimazaki; M. Oowa; M. Matsuo; Y. Yoshida

    1999-01-01

    There are two promising candidates as alternative refrigerants for air-conditioners and heat pumps. The first is R407C, which is composed of HFC-32 (23 mass%), HFC-125 (25 mass%), and HFC-134a (52 mass%). The second is R410A, which is composed of HFC-32 (50 mass%) and HFC-125 (50 mass%). In this study, formation conditions of clathrate compounds between water and HFC alternative refrigerants

  7. Performance of a Small-sized Refrigeration Comperssor Using HFC-134a

    NASA Astrophysics Data System (ADS)

    Kohsokabe, Hirokatsu; Endoh, Kazuhiro; Kunugi, Yoshifumi; Iwata, Hiroshi; Hata, Hiroaki; Fujiwara, Mitsuru

    When CFC-12 is replaced by HFC-134a in small-sized refrigeration compressors for domestic refrigerators, the coefficient of performance (COP) of rotary compressors decreases. On the other hand,the COP of reciprocating compressors is almost the same as that of CFC-12. The main causes of rotary compressor performance decrease are higher viscosity of HFC-134a/oil mixture,and greater re-expansion loss of gas in clearance volume. The performance is improved by optimizing the oil viscosity through directly measuring viscosity of HFC-134a/oil mixture inside the compressor chamber with a viscosity sensor. Difference of oil type has small influence on the COP.

  8. New concepts for refrigerant leak detection and mixture measurement

    NASA Astrophysics Data System (ADS)

    Chen, F. C.; Allman, S. L.; Chen, C. H.

    Since the discovery that chlorofluorocarbons (CFC's) destroy the ozone layer, the need to reduce the release of these refrigerants into the environment has become critical. A total ban of ozone-depleting CFC's is expected within a few years, and hydrofluorocarbons (HFC's) and fluorocarbons (FC's) and their mixtures are expected to be used during a transition period. Several HFC and FC refrigerants are currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently on the market were developed to detect CFC's and are not as sensitive to HFC's. Although incremental improvement can be made to these devices to detect HFC's, they often lead to increased false signals. Also, there is no simple device available to measure the composition of a refrigerant mixture. The authors present two new concepts to aid in the development of two portable instruments that can be used for HFC leak detection and for quantitative measurement of refrigerant mixture compositions. The development of simple, easy-to-use portable leak detectors and refrigerant mixture meters is essential to the wide use of alternative refrigerants in industry.

  9. Lubrication of rolling element bearings with HFC–polyolester mixtures

    Microsoft Academic Search

    Ulf J Jonsson

    1999-01-01

    Manufacturers of refrigeration and air-conditioning compressors have had to re-evaluate their knowledge of compressor bearing lubrication following the introduction of hydrofluorocarbon (HFC) refrigerants and polyolester lubricants. The lack of anti wear protection in comparison to traditionally used refrigerants\\/lubricants makes the lubrication of bearings using these modern systems a much more difficult task than before. This paper presents results from ongoing

  10. Cycle performance testing of nonazeotropic mixtures of HFC-142a/HCFC-124 and HFC-32/HCFC-124 with enhanced surface heat exchangers

    SciTech Connect

    Vineyard, E.A.; Conklin, J.C.; Brown, A.J.

    1993-01-01

    In an effort to improve the efficiency of residential heat pumps using altemative refrigerants, two nonazeotropic refrigerant mixtures (NARMs) were tested over a range of heat exchanger capacities to determine their cooling mode performance at US Department of Energy (DOE) heat pump rating conditions of 82[degrees]F (27.8[degrees]C). The two mixtures, 30% HFC-32/70% HCFC-124 and 75% HFC-143a/25% HCFC-124, were selected on the basis of a previous study that screened refrigerant pairs using such factors as boiling point, stability, ozone depletion potential (ODP), and coefficient of performance (COP) to determine suitable candidates for residential heat pump performance. Three refigerant-side heat transfer enhancements were tested to determine improvements to overall system performance. Comparisons were made on the basis of the COP as a function of capacity. The results for one of the heat exchanger combinations, a segmented evaporator and finned condenser, were quite promising. Improvements in COP, relative to that for HCFC-22, were from 9 to 17% for the 30% HFC-32/70% HCFC-124 mixture and from 5 to 9% for the 75% HFC-143a/25% HCFC-124 NARM. Another combination, a smooth tube evaporator with a perforated foil insert and finned condenser, had similar gains at low capacities but experienced decreased performance at the higher capacities. The final combination, a smooth tube evaporator with a perforated foil insert and smooth tube condenser with a benttab insert resulted in poor performance.

  11. Cycle performance testing of nonazeotropic mixtures of HFC-142a/HCFC-124 and HFC-32/HCFC-124 with enhanced surface heat exchangers

    SciTech Connect

    Vineyard, E.A.; Conklin, J.C.; Brown, A.J.

    1993-06-01

    In an effort to improve the efficiency of residential heat pumps using altemative refrigerants, two nonazeotropic refrigerant mixtures (NARMs) were tested over a range of heat exchanger capacities to determine their cooling mode performance at US Department of Energy (DOE) heat pump rating conditions of 82{degrees}F (27.8{degrees}C). The two mixtures, 30% HFC-32/70% HCFC-124 and 75% HFC-143a/25% HCFC-124, were selected on the basis of a previous study that screened refrigerant pairs using such factors as boiling point, stability, ozone depletion potential (ODP), and coefficient of performance (COP) to determine suitable candidates for residential heat pump performance. Three refigerant-side heat transfer enhancements were tested to determine improvements to overall system performance. Comparisons were made on the basis of the COP as a function of capacity. The results for one of the heat exchanger combinations, a segmented evaporator and finned condenser, were quite promising. Improvements in COP, relative to that for HCFC-22, were from 9 to 17% for the 30% HFC-32/70% HCFC-124 mixture and from 5 to 9% for the 75% HFC-143a/25% HCFC-124 NARM. Another combination, a smooth tube evaporator with a perforated foil insert and finned condenser, had similar gains at low capacities but experienced decreased performance at the higher capacities. The final combination, a smooth tube evaporator with a perforated foil insert and smooth tube condenser with a benttab insert resulted in poor performance.

  12. An Experimental Investigaton of the Effect of Oil on Convective Heat Trasfer and Pressure Drop of a HFC-32/HRC-125 Mixture 

    E-print Network

    McJimsey, Bert Ashford

    1994-01-01

    The heat transfer coefficients and pressure drops of HCFC-22 and a 50% mass mixture of HFC-32/HFC-125 were experimentally measured under flow boiling conditions in a smooth tube. The refrigerants were flowed through an 8 mm diameter smooth tube...

  13. Solubility, viscosity and density of refrigerant/lubricant mixtures

    SciTech Connect

    Henderson, D.R.

    1993-04-01

    This report presents results for low refrigerant concentration (70, 80, 90 and 100 weight percent lubricant) mixtures of the following fluids: CFC-12/ISO 32 naphthenic mineral oil, HCFC-22/ISO 32 naphthenic mineral oil, CFC-12/ISO 100 naphthenic mineral oil, HFC-134a/ISO 22 pentaerythritol ester mixed acid, HFC-134a/ISO 32 pentaerythritol ester mixed acid [number sign]1, HFC-134a/ISO 68 pentaerythritol ester mixed acid, HFC-134a/ISO 100 pentaerythritol ester mixed acid, HFC-134a/ISO 32 pentaerythritol ester mixed acid [number sign]2, HCFC-123/ISO 32 naphthenic mineral oil, HCFC-123/ISO 100 naphthenic mineral oil, HCFC-123/150 SUS alkylbenzene, HCFC-123/300 SUS alkylbenzene. These data have been reduced to engineering form and are presented in the form of a Daniel Chart. Equations are given along with statistical measures of goodness of fit.

  14. Exploring policy strategies for mitigating HFC emissions from refrigeration and air conditioning

    Microsoft Academic Search

    M. Hekkenberg; Anton J. M. Schoot Uiterkamp

    2007-01-01

    The growing demand for cooling throughout the world, possibly increased by global climate change, requires the implementation of policies to mitigate the related greenhouse gas (GHG) emissions from energy and refrigerant use in the refrigeration and air conditioning (RAC) sector. This article aims to contribute to the discussion on strategies to reduce HFC emissions from RAC by looking at their

  15. New concepts for refrigerant leak detection and mixture measurement

    SciTech Connect

    Chen, F.C.; Allman, S.L.; Chen, C.H.

    1993-12-31

    Since the discovery that chlorofluorocarbons (CFCs) destroy the ozone layer, the need to reduce the release of these refrigerants into the environment has become critical. A total ban of ozone-depleting CFCs is expected within a few years, and hydrofluorocarbons (HFCs) and fluorocarbons (FCs) and their mixtures are expected to be used during a transition period. Several HFC and FC refrigerants are currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently on the market were developed to detect CFCs and are not as sensitive to HFCs. Although incremental improvement can be made to these devices to detect HFCs, they often lead to increased false signals. Also, there is no simple device available to measure the composition of a refrigerant mixture. The authors present two new concepts to aid in the development of two portable instruments that can be used for HFC leak detection and for quantitative measurement of refrigerant mixture compositions. The development of simple, easy-to-use portable leak detectors and refrigerant mixture meters is essential to the wide use of alternative refrigerants in industry.

  16. Helmholtz Energy Equations of State for HFC and Natural Refrigerants and Their Applications to Calculations of Thermodynamic Properties

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

    This paper overviews Helmholtz energy equations of state for pure HFC and natural refrigerants. The equations of state consist of the ideal-gas part and the residual part. The ideal-gas part can be calculated from the ideal-gas isobaric heat capacity according to the ideal-gas law, and the residual part is determined empirically by fitting to experimental thermodynamic property data. Polynomial and exponential terms are used to represent the residual part. Some equations have more complex terms for accurate descriptions of critical behavior. Mixture models for applications of the pure-fluid equations of state to refrigerant mixtures are summarized. Until now, two mixture models have been developed for HFC refrigerant mixtures. This paper also discusses calculation methods for the pvT relation, vapor-liquid equilibrium, and critical point using Helmholtz energy equations of state. Few literature discusses the methods in detail, although such information is very precious to make a computer program for calculating thermodynamic properties.

  17. MODELING AND DESIGN STUDY USING HFC-236EA AS AN ALTERNATIVE REFRIGERANT IN A CENTRIFUGAL COMPRESSOR

    EPA Science Inventory

    The report gives results of an investigation of the operation of a centrifugal compressor--part of a chlorofluorocarbon (CFC)-114 chiller installation--with the new refrigerant hydrofluorocarbon (HFC)-236ea, a proposed alternative to CFC-114. A large set of CFC-236ea operating da...

  18. Global Emissions of Refrigerants HCFC-22 and HFC-134a: Unforeseen Seasonal Contributions

    NASA Astrophysics Data System (ADS)

    Xiang, B.; Patra, P. K.; Montzka, S. A.; Miller, S. M.; Elkins, J. W.; Moore, F.; Atlas, E. L.; Miller, B. R.; Prinn, R. G.; Wofsy, S. C.

    2014-12-01

    HCFC-22 (CHClF2) and HFC-134a (CH2FCF3) are two major gases currently used worldwide in domestic and commercial refrigeration and air conditioning. HCFC-22 contributes to stratospheric ozone depletion and both species are potent greenhouse gases, and their global emissions continue to rise at the present. In this work, we study aircraft based in-situ observations of HCFC-22 and HFC-134a over the Pacific Ocean in a three-year span (HIaper Pole-to-Pole Observation of carbon cycle and greenhouse gases study, HIPPO 2009-2011) and combine these data with long-term observations from global surface sites (NOAA and AGAGE networks). We find a steady increase in global annual emissions of HCFC-22 and HFC-134a for the past two decades (on average 3% and 4% per year, respectively). Emissions of HFC-134a since 2000 are consistently higher, with 60% more in recent years (2009-2011), compared to the United Nations Framework Convention on Climate Change (UNFCCC) inventory. Using both HIPPO and surface data, we quantify and verify enhanced summertime emissions of HFC-134a and HCFC-22 that are about three times those in the wintertime. This unforeseen large seasonal contribution indicates unaccounted mechanisms controlling refrigerant gas emissions, missing in the existing inventory estimates. Possible mechanisms for greater refrigerant leakages in the summer are: 1) higher vapor pressure in the sealed compartment of the system at summer high temperatures (saturated vapor pressure is ~ 3 times at 303 K compared to that at 273 K for both species), and 2) more frequent use of refrigeration and air conditioners in the summer (vapor pressure in the compressor line is higher when in use than not in use). Our results suggest that the engineering of the refrigeration and air conditioning systems can greatly influence the release of these two species to the atmosphere.

  19. Global emissions of refrigerants HCFC-22 and HFC-134a: unforeseen seasonal contributions.

    PubMed

    Xiang, Bin; Patra, Prabir K; Montzka, Stephen A; Miller, Scot M; Elkins, James W; Moore, Fred L; Atlas, Elliot L; Miller, Ben R; Weiss, Ray F; Prinn, Ronald G; Wofsy, Steven C

    2014-12-01

    HCFC-22 (CHClF2) and HFC-134a (CH2FCF3) are two major gases currently used worldwide in domestic and commercial refrigeration and air conditioning. HCFC-22 contributes to stratospheric ozone depletion, and both species are potent greenhouse gases. In this work, we study in situ observations of HCFC-22 and HFC-134a taken from research aircraft over the Pacific Ocean in a 3-y span [HIaper-Pole-to-Pole Observations (HIPPO) 2009-2011] and combine these data with long-term ground observations from global surface sites [National Oceanic and Atmospheric Administration (NOAA) and Advanced Global Atmospheric Gases Experiment (AGAGE) networks]. We find the global annual emissions of HCFC-22 and HFC-134a have increased substantially over the past two decades. Emissions of HFC-134a are consistently higher compared with the United Nations Framework Convention on Climate Change (UNFCCC) inventory since 2000, by 60% more in recent years (2009-2012). Apart from these decadal emission constraints, we also quantify recent seasonal emission patterns showing that summertime emissions of HCFC-22 and HFC-134a are two to three times higher than wintertime emissions. This unforeseen large seasonal variation indicates that unaccounted mechanisms controlling refrigerant gas emissions are missing in the existing inventory estimates. Possible mechanisms enhancing refrigerant losses in summer are (i) higher vapor pressure in the sealed compartment of the system at summer high temperatures and (ii) more frequent use and service of refrigerators and air conditioners in summer months. Our results suggest that engineering (e.g., better temperature/vibration-resistant system sealing and new system design of more compact/efficient components) and regulatory (e.g., reinforcing system service regulations) steps to improve containment of these gases from working devices could effectively reduce their release to the atmosphere. PMID:25422438

  20. Global emissions of refrigerants HCFC-22 and HFC-134a: Unforeseen seasonal contributions

    PubMed Central

    Xiang, Bin; Montzka, Stephen A.; Miller, Scot M.; Elkins, James W.; Moore, Fred L.; Atlas, Elliot L.; Miller, Ben R.; Weiss, Ray F.; Prinn, Ronald G.; Wofsy, Steven C.

    2014-01-01

    HCFC-22 (CHClF2) and HFC-134a (CH2FCF3) are two major gases currently used worldwide in domestic and commercial refrigeration and air conditioning. HCFC-22 contributes to stratospheric ozone depletion, and both species are potent greenhouse gases. In this work, we study in situ observations of HCFC-22 and HFC-134a taken from research aircraft over the Pacific Ocean in a 3-y span [HIaper-Pole-to-Pole Observations (HIPPO) 2009–2011] and combine these data with long-term ground observations from global surface sites [National Oceanic and Atmospheric Administration (NOAA) and Advanced Global Atmospheric Gases Experiment (AGAGE) networks]. We find the global annual emissions of HCFC-22 and HFC-134a have increased substantially over the past two decades. Emissions of HFC-134a are consistently higher compared with the United Nations Framework Convention on Climate Change (UNFCCC) inventory since 2000, by 60% more in recent years (2009–2012). Apart from these decadal emission constraints, we also quantify recent seasonal emission patterns showing that summertime emissions of HCFC-22 and HFC-134a are two to three times higher than wintertime emissions. This unforeseen large seasonal variation indicates that unaccounted mechanisms controlling refrigerant gas emissions are missing in the existing inventory estimates. Possible mechanisms enhancing refrigerant losses in summer are (i) higher vapor pressure in the sealed compartment of the system at summer high temperatures and (ii) more frequent use and service of refrigerators and air conditioners in summer months. Our results suggest that engineering (e.g., better temperature/vibration-resistant system sealing and new system design of more compact/efficient components) and regulatory (e.g., reinforcing system service regulations) steps to improve containment of these gases from working devices could effectively reduce their release to the atmosphere. PMID:25422438

  1. Releases of refrigerant gases (CFC-12, HCFC-22 and HFC-134a) to the atmosphere

    NASA Astrophysics Data System (ADS)

    McCulloch, Archie; Midgley, Pauline M.; Ashford, Paul

    Two of the gases, CFC-12 (dichlorodifluoromethane, CF 2Cl 2) and HCFC-22 (chlorodifluoromethane, CHClF 2) have long histories of emission from refrigeration and other uses. Production and sales records show the expected fall in the amounts of CFC-12 used in refrigeration after the Montreal Protocol came into effect but this does not seem to have been accompanied by significant substitution by HCFC-22, demand for which appears governed by organic growth. HFC-134a (1,1,1,2-tetrafluoroethane, CH 2FCF 3) is a relative newcomer that has partially substituted for CFC-12. After developing a single data set for the global use of each substance in refrigeration, foam blowing and aerosol propulsion, and other promptly emissive uses, annual releases of the compounds were estimated by applying emission functions derived from surveying both the producers of the chemicals and the principal industrial users. For CFC-12 and HFC-134a, atmospheric concentrations calculated from the emissions estimated here are in good agreement with observations, verifying that the emission functions adequately describe the relationship between the quantities in use, the atmospheric lifetimes of 100 and 14.6 years, respectively, and the extent of release into the atmosphere. The agreement between observation and calculation is poorer for HCFC-22, if its atmospheric lifetime is 12 years, but becomes much closer with a lifetime of 10 years. An 80% reduction in CFC requirement has been substituted only to the extent of 25% by HFC-134a. This is consistent with improved technology to curtail leakage and so enable lower system charges that, in turn, translate into less demand. For the same reason, the refrigeration emission function for HFC-134a over the period 1990-2000 was not significantly different from that of CFC-12. The lower absolute rate of leakage and lower absolute charge sizes combining to maintain a similar relative rate of loss.

  2. Solubility, viscosity and density of refrigerant/lubricant mixtures

    SciTech Connect

    Henderson, D.R.

    1993-01-01

    This report presents results on low refrigerant concentration (70, 80, 90, and 100 weight percent lubricant) mixtures of the following fluids: CFC-12/ISO 32 naphthenic mineral oil; HCFC-22/ISO 32 naphthenic mineral oil; and HFC-134a/ISO 32 pentaerythritol ester mixed acid. These data have been reduced to engineering form and are presented in the form of a Daniel Chart. Scatter diagrams are given for the first fluid listed above, with the intent of illustrating the quality of data as well as providing the rationale for selecting the particular functional forms chosen to represent the experimental data. Equations are given along with statistical measures of goodness of fit.

  3. Nucleate pool boiling heat transfer coefficients of pure HFC134a, HC290, HC600a and their binary and ternary mixtures

    Microsoft Academic Search

    Zhaohu Sun; Maoqiong Gong; Zhijian Li; Jianfeng Wu

    2007-01-01

    An experimental test rig for study on the pooling-boiling heat transfer performance of pure and mixed refrigerants were designed and established. With this test system, the heat transfer coefficients (HTCs) of the nucleate boiling on a smooth flat surface were measured for pure fluids of HFC134a, HC290, HC600a and their binary and ternary mixtures. Extensive experimental measures were made for

  4. Solubility, viscosity and density of refrigerant/lubricant mixtures. Quarterly technical progress report, 1 January--31 March 1993

    SciTech Connect

    Henderson, D.R.

    1993-04-01

    This report presents results for low refrigerant concentration (70, 80, 90 and 100 weight percent lubricant) mixtures of the following fluids: CFC-12/ISO 32 naphthenic mineral oil, HCFC-22/ISO 32 naphthenic mineral oil, CFC-12/ISO 100 naphthenic mineral oil, HFC-134a/ISO 22 pentaerythritol ester mixed acid, HFC-134a/ISO 32 pentaerythritol ester mixed acid {number_sign}1, HFC-134a/ISO 68 pentaerythritol ester mixed acid, HFC-134a/ISO 100 pentaerythritol ester mixed acid, HFC-134a/ISO 32 pentaerythritol ester mixed acid {number_sign}2, HCFC-123/ISO 32 naphthenic mineral oil, HCFC-123/ISO 100 naphthenic mineral oil, HCFC-123/150 SUS alkylbenzene, HCFC-123/300 SUS alkylbenzene. These data have been reduced to engineering form and are presented in the form of a Daniel Chart. Equations are given along with statistical measures of goodness of fit.

  5. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 2

    SciTech Connect

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

    Lubrication properties of refrigeration lubricants were investigated in high pressure nonconforming contacts under different conditions of temperature, rolling speed, and refrigerant concentration. The program was based upon the recognition that the lubrication regime in refrigeration compressors is generally elastohydrodynamic or hydrodynamic, as determined by the operating conditions of the compressor and the properties of the lubricant. Depending on the compressor design, elastohydrodynamic lubrication conditions exist in many rolling and sliding elements of refrigeration compressors such as roller element bearings, gears, and rotors. The formation of an elastohydrodynamic film separating rubbing surfaces is important in preventing the wear and failure of compressor elements. It is, therefore, important to predict the elastohydrodynamic (EHD) performance of lubricants under realistic tribocontact renditions. This is, however, difficult as the lubricant properties that control film formation are critically dependent upon pressure and shear, and cannot be evaluated using conventional laboratory instruments. In this study, the elastohydrodynamic behavior of refrigeration lubricants with and without the presence of refrigerants was investigated using the ultrathin film EHD interferometry technique. This technique enables very thin films, down to less than 5 nm, to be measured accurately within an EHD contact under realistic conditions of temperature, shear, and pressure. The technique was adapted to the study of lubricant refrigerant mixtures. Film thickness measurements were obtained on refrigeration lubricants as a function of speed, temperature, and refrigerant concentration. The effects of lubricant viscosity, temperature, rolling speed, and refrigerant concentration on EHD film formation were investigated. From the film thickness measurements, effective pressure-viscosity coefficients were calculated. The lubricants studied in this project included two naphthenic mineral oils (NMO), four polyolesters (POE), and two polyvinyl ether (PVE) fluids. These fluids represented viscosity grades of ISO 32 and ISO 68 and are shown in a table. Refrigerants studied included R-22, R-134a, and R-410A. Film thickness measurements were conducted at 23 C, 45 C, and 65 C with refrigerant concentrations ranging from zero to 60% by weight.

  6. 40 CFR Appendix D to Subpart B of... - SAE J2810 Standard for Recovery Only Equipment for HFC-134a Refrigerant

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...the appropriate ARI 700 Standard or allow for recycling of the recovered refrigerant to SAE J2788...SAE J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  7. 40 CFR Appendix D to Subpart B of... - SAE J2810 Standard for Recovery Only Equipment for HFC-134a Refrigerant

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...the appropriate ARI 700 Standard or allow for recycling of the recovered refrigerant to SAE J2788...SAE J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  8. 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.

  9. Development of New Refrigeration Circuit to Control Refrigerant Mixture Composition

    NASA Astrophysics Data System (ADS)

    Yoshida, Yuji; Suzuki, Sigeo; Nakatani, Kazuo; Mukai, Yuji; Adachi, Masaaki

    The use of refrigerant mixture is an important subject of heat-pump technology and its research and developments have been promoted all over the world. We have tried to apply mixed refrigerants to air-conditioners, and developed an unique technology for efficiently separating and varying the mixing ratio of the refrigerants inside the refrigeration circuit. The mixed fluorinated refrigerants of R22-R13B1 were adapted to increase the heating capacity. Effects of shapes of packings and diameters of column were examined by an experimental apparatus of rectifier only, and a small rectifier with new coiled packings was developed. In the new circuit, the bottom of the rectifier is connected with condenser and evaporator by lines in parallel with expansion device. In the rectifying mode, the lower boiling-point refrigerant is stored in a reservoir connected to the top of the rectifier, and a main circuit is operated with the higher boiling-point refrigerant. Then the heating capacity, the input wattage and the fluid pressure of a heat-pump operating with the separated refrigerants are decreased to a lower level and its energy efficiency was improved through an inspection of the rectifying vapour generation method. The technique of estimating the composition of mixture operating in the circuit was developed, too, and the calculated values almost coincide with the experimetal values.

  10. Calculating Circulation Concentration of Zeotropic Refrigerant Mixtures

    Microsoft Academic Search

    J. Chen; H. Kruse

    1995-01-01

    The circulation concentration of a zeotropic refrigerant mixture may differ from the refrigerant bulk concentration in a vapor compression cycle. The difference, defined as “concentration shift,” is mainly caused by the differential holdup in two-phase regions and the differential solubility of the oil. In this paper the concentration shift caused by the differential holdup of the two-phase flow of liquid

  11. Modeling and design study using HFC-236ea as an alternative refrigerant in a centrifugal compressor. Final report, January 1994-September 1995

    SciTech Connect

    Popovic, P.; Shapiro, H.N.

    1997-04-01

    The Environmental Protection Agency (EPA) in cooperation with the Navy has been seeking a CFC-114 drop-in placement. One alternative HFC refrigerant which appears to satisfy all physical and chemical characteristics for the Navy fleet was found to be HFC-236ea refrigerant. The project represents a part of the investigation directed to evaluate this CFC-114 alternative refrigerant as a possible drop-in replacement in Navy chillers. The objective of the study was to conduct a thorough literature review regarding centrifugal compressors and the, on the basis of the information gathered, build an accurate but simple compressor model utilizing the available compressor experimental data. Further, the developed compressor model would be used to suggest eventual design adjustments to enhance compressor performance with the alternative HFC-236ea refrigerant.

  12. Frontiers in thermoacoustic refrigeration and mixture separation

    E-print Network

    Frontiers in thermoacoustic refrigeration and mixture separation S. Backhaus1 , D. Geller2 , B a combustion-powered thermoacoustic natural gas liquefier, radioisotope and reactor-driven thermoacoustic engines for generating electrical power on spacecraft, and heat-driven thermoacoustic engines and engine

  13. Estimated 2017 Refrigerant Emissions of 2,3,3,3-Tetrafluoropropene (HFC-1234yf) in the United States Resulting from Automobile Air Conditioning

    EPA Science Inventory

    In response to recent regulations and concern over climate change, the global automotive community is evaluating alternatives to the current refrigerant used in automobile air conditioning units, 1,1,1,2-tetrafluoroethane, HFC-134a. One potential alternative is 2,3,3,3-tetrafluor...

  14. Estimated 2017 refrigerant emissions of 2,3,3,3-tetrafluoropropene (HFC-1234yf) in the United States resulting from automobile air conditioning.

    PubMed

    Papasavva, Stella; Luecken, Deborah J; Waterland, Robert L; Taddonio, Kristen N; Andersen, Stephen O

    2009-12-15

    In response to recent regulations and concern over climate change, the global automotive community is evaluating alternatives to the current refrigerant used in automobile air conditioning units, 1,1,1,2-tetrafluoroethane, HFC-134a. One potential alternative is 2,3,3,3-tetrafluoropropene (HFC-1234yf, also known as HFO-1234yf). We have developed a spatially and temporally resolved inventory of likely future HFC refrigerant emissions from the U.S. vehicle fleet in 2017, considering regular, irregular, servicing, and end-of-life leakages. We estimate the annual leak rate emissions for each leakage category for a projected 2017 U.S. vehicle fleet by state, and spatially apportion these leaks to a 36 km square grid over the continental United States. This projected inventory is a necessary first step in analyzing for potential atmospheric and ecosystem effects, such as ozone and trifluoroacetic acid production, that might result from widespread replacement of HFC-134a with HFC-1234yf. PMID:20000517

  15. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 1

    SciTech Connect

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

    The objective of this study was to investigate the film formation properties of refrigeration lubricants using the ultrathin film elastohydrodynamic (EHD) interferometry technique and to study the effects of refrigerants on film formation. Film thickness measurements were conducted as a function of lubricant viscosity, speed, temperature, and refrigerant concentration. Based on the EHD film thickness data, effective pressure-viscosity coefficients were calculated for the test fluids at different temperatures and the effects of refrigerants on pressure-viscosity properties were investigated.

  16. Evaluation of mixtures efficiency in refrigerating systems

    Microsoft Academic Search

    A. Stegou-Sagia; N. Paignigiannis

    2005-01-01

    The use of many common refrigerants is under restriction or phase out because of their high ODP (ozone depletion potential) or GWP (global warming potential). The regulations on environmentally acceptable substances are different from country to country and are subject to frequent updates. In our article, the following mixtures are under consideration: R-401B, R-401C, R-402A, R-404A, R-406A, R-408A, R-409A, R-410A,

  17. GAS CHROMATOGRAPHIC RETENTION PARAMETERS DATABASE FOR REFRIGERANT MIXTURE COMPOSITION MANAGEMENT

    EPA Science Inventory

    Composition management of mixed refrigerant systems is a challenging problem in the laboratory, manufacturing facilities, and large refrigeration machinery. Ths issue of composition management is especially critical for the maintenance of machinery that utilizes zeotropic mixture...

  18. Phase and viscosity behaviour of refrigerant–lubricant mixtures

    Microsoft Academic Search

    S. E. Quiñones-Cisneros; J. García; J. Fernández; M. A. Monsalvo

    2005-01-01

    The understanding of thermophysical properties and phase behaviour of refrigerant–lubricant oil mixtures is highly important for the optimal design of refrigeration and air-conditioning systems. Refrigerant–lubricant mixtures, which are likely to have strong asymmetry, can show complex phase behaviour such as closed miscibility gaps, open miscibility gaps, liquid–liquid–vapour equilibrium, and even barotropic phenomena (density inversions). In fact, the type of phase

  19. Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants. Final report, Part 1

    SciTech Connect

    Cavestri, R.C. [Imagination Resources, Inc., Dublin, OH (United States)

    1997-07-01

    Part one of this research provides manufacturers of components of air-conditioning and refrigeration equipment with a useful list of lubricant additives, sources, functional properties and chemical species. The list in part one is comprised of domestic lubricant additive suppliers and the results of a literature search that was specifically targeted for additives reported to be useful in polyolester chemistry.

  20. Energy and global warming impacts of HFC refrigerants and emerging technologies: TEWI-III

    SciTech Connect

    Sand, J.R.; Fischer, S.K.; Baxter, V.D.

    1997-06-01

    The use of hydrofluorocarbons (BFCs) which were developed as alternative refrigerants and insulating foam blowing agents to replace chlorofluorocarbons (CFCs) is now being affected by scientific investigations of greenhouse warming and questions about the effects of refrigerants and blowing agents on global warming. A Total Equivalent Warming Impact (TEWI) assessment analyzes the environmental affects of these halogenated working fluids in energy consuming applications by combining a direct effect resulting from the inadvertent release of HFCs to the atmosphere with an indirect effect resulting from the combustion of fossil fuels needed to provide the energy to operate equipment using these compounds as working fluids. TEWI is a more balanced measure of environmental impact because it is not based solely on the global warming potential (GWP) of the working fluid. It also shows the environmental benefit of efficient technologies that result in less CO{sub 2} generation and eventual emission to the earth`s atmosphere. The goal of TEWI is to assess total global warming impact of all the gases released to the atmosphere, including CO{sub 2} emissions from energy conversion. Alternative chemicals and technologies have been proposed as substitutes for HFCs in the vapor-compression cycle for refrigeration and air conditioning and for polymer foams in appliance and building insulations which claim substantial environmental benefits. Among these alternatives are: (1) Hydrocarbon (HC) refrigerants and blowing agents which have zero ozone depleting potential and a negligible global warming potential, (2) CO{sub 2} as a refrigerant and blowing agent, (3) Ammonia (NH{sub 3}) vapor compression systems, (4) Absorption chiller and heat pumping cycles using ammonia/water or lithium bromide/water, and (5) Evacuated panel insulations. This paper summarizes major results and conclusions of the detailed final report on the TEWI-111 study.

  1. Solubility, viscosity and density of refrigerant/lubricant mixtures. Quarterly technical progress report, 1 October--31 December 1992

    SciTech Connect

    Henderson, D.R.

    1993-01-01

    This report presents results on low refrigerant concentration (70, 80, 90, and 100 weight percent lubricant) mixtures of the following fluids: CFC-12/ISO 32 naphthenic mineral oil; HCFC-22/ISO 32 naphthenic mineral oil; and HFC-134a/ISO 32 pentaerythritol ester mixed acid. These data have been reduced to engineering form and are presented in the form of a Daniel Chart. Scatter diagrams are given for the first fluid listed above, with the intent of illustrating the quality of data as well as providing the rationale for selecting the particular functional forms chosen to represent the experimental data. Equations are given along with statistical measures of goodness of fit.

  2. Azeotropy in the natural and synthetic refrigerant mixtures

    Microsoft Academic Search

    Sergey Artemenko; Victor Mazur

    2007-01-01

    A novel approach for the prediction of azeotrope formation in a mixture that does not require vapour–liquid equilibrium calculations is developed. The method employs neural networks and global phase diagram methodologies to correlate azeotropic data for binary mixtures based only on critical properties and acentric factor of the individual components in refrigerant mixtures. Analytical expressions to predict azeotropy and double

  3. The application of propane\\/butane mixture for domestic refrigerators

    Microsoft Academic Search

    M. A. Alsaad; M. A. Hammad

    1998-01-01

    This work investigates the result of an experimental study carried out to determine the performance of a domestic refrigerator when a propane\\/butane mixture is used as a possible replacement to the traditional refrigerant CFC 12. The used propane\\/butane mixture is liquefied petroleum gas (LPG) which is locally available and comprises 24.4% propane, 56.4% butane and 17.2% isobutane. The LPG is

  4. The Influence of the Lubricant Mixture into a Refrigerant on the Condensation Heat Transfer in Tube

    NASA Astrophysics Data System (ADS)

    Katsuta, Masafumi; Miyai, Ryo; Komatsu, Tomohiro; Kawai, Akinari

    In a refrigerator and an air conditioner, it is a well-known fact that the contamination of lubricant into a pure refrigerant has a great influence on the heat transfer characteristics and two-phase flow behavior at the condenser and evaporator. However, up to now, in the most of heat exchanger design, the refrigerant has been regarded as a pure one. On the other hand, a recent condenser tube diameter tends to be fine to overcome the various demands on the compactness and the high performance, especially required for the alternative refrigerant. Unfortunately, quantitative studies of the tube less than 6 mm in diameter were insufficient, moreover, only few studies have been made including the effect of the oil contamination on the condensation heat transfer. In this study, we employed HFC134a as a refrigerant and PAG-oil as a lubricant and experiments with a flat tube and three kinds of circular tube which has different diameters were made. By using the flow visualization data, a new flow pattern map being applicable both of a pure and oil-lubricant mixture was proposed. Moreover, by examining the local heat transfer coefficient and pressure drop, the most sensitive flow pattern affected by contamination of lubricant was specified and the detailed discussion on the quantitative effect of oil contamination on condensation heat transfer including the effect of tube geometry was carried out. Finally, based on these results, new correlation for heat transfer and pressure drop was suggested, and it predicted our data successfully well up to a mass flux of 150kg/(m2•s.)

  5. 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.

  6. Solubility, viscosity and density of refrigerant/lubricant mixtures. Quarterly technical progress report, 1 July 1993--30 September 1993

    SciTech Connect

    Henderson, D.R.

    1993-10-01

    This report presents results of measurements on low refrigerant concentration mixtures (0, 10, 20, 30 wt %) of CFC-12, HCFC`s 22, 123 and 124, HFC`s 134a, 32 and 125 with mineral oil, alkylbenzene and polyolester lubricants. Viscosity, solubility (vapor pressure) and density data are reported for 23 working fluids composed of combinations of these refrigerants and companion lubricants. These data, reduced to engineering form, are presented in form of a Daniel Chart and a plot of density vs temperature and composition. Extensive numerical analysis has been performed in order to derive equations which allow two independent variables (temperature and composition) and to provide for corrections in composition due to vapor space volume in the test apparatus; details of these calculations are provided.

  7. Advantages of enthalpy-temperature diagrams for nonazeotropic refrigerant mixtures

    SciTech Connect

    Granryd, E. (Royal Inst. of Tech., Stockholm (Sweden). Dept. of Applied Thermodynamics and Refrigeration); Conklin, J.C.; Sand, J.R. (Oak Ridge National Lab., TN (United States))

    1991-08-15

    The enthalpy-temperature diagram for nonazeotropic refrigerant mixtures has illustrative and useful features, combining the advantages of the entropy-temperature diagram and the enthalpy-pressure diagram commonly used in the refrigeration and heat pump industry. Plotting temperature versus enthalpy has advantages similar to those of plotting pressure versus enthalpy, and has the additional advantages of depicting the temperature profiles for both sides of the heat exchange equipment during the cycle. This additional advantage is particularly useful for analyzing the vapor compression refrigeration cycle using nonazeotropic refrigerant mixtures, where nonisothermal phase-change processes occur. Problems such as heat exchanger pinch-points and wet compression are easily detected. The possible cycle enhancement due to a liquid-to-suction heat exchanger is readily apparent. This paper presents and discusses examples of enthalpy-temperature diagrams. 10 refs., 8 figs.

  8. Advantages of enthalpy-temperature diagrams for nonazeotropic refrigerant mixtures

    NASA Astrophysics Data System (ADS)

    Granryd, E.; Conklin, J. C.; Sand, J. R.

    1991-08-01

    The enthalpy-temperature diagram for nonazeotropic refrigerant mixtures has illustrative and useful features, combining the advantages of the entropy-temperature diagram and the enthalpy-pressure diagram commonly used in the refrigeration and heat pump industry. Plotting temperature versus enthalpy has advantages similar to those of plotting pressure versus enthalpy, and has the additional advantages of depicting the temperature profiles for both sides of the heat exchange equipment during the cycle. This additional advantage is particularly useful for analyzing the vapor compression refrigeration cycle using nonazeotropic refrigerant mixtures, where nonisothermal phase-change processes occur. Problems such as heat exchanger pinch-points and wet compression are easily detected. The possible cycle enhancement due to a liquid-to-suction heat exchanger is readily apparent. This paper presents and discusses examples of enthalpy-temperature diagrams.

  9. Advantages of enthalpy-temperature diagrams for nonazeotropic refrigerant mixtures

    Microsoft Academic Search

    E. Granryd; J. C. Conklin; J. R. Sand

    1991-01-01

    The enthalpy-temperature diagram for nonazeotropic refrigerant mixtures has illustrative and useful features, combining the advantages of the entropy-temperature diagram and the enthalpy-pressure diagram commonly used in the refrigeration and heat pump industry. Plotting temperature versus enthalpy has advantages similar to those of plotting pressure versus enthalpy, and has the additional advantages of depicting the temperature profiles for both sides of

  10. Tubeside condensation of nonazeotropic refrigerant mixtures for two enhanced surfaces

    SciTech Connect

    Conklin, J.C.; Vineyard, E.A.

    1990-01-01

    As part of the Building Equipment Research program at Oak Ridge National Laboratory (ORNL), nonazeotropic refrigerant mixtures (NARMs) are being investigated to replace chlorofluorocarbon compounds. The condensation of NARMs is not isothermal, and this can improve the heat exchanger effectiveness of a condenser as well as improve thermodynamic cycle efficiencies. The total condensing heat transfer coefficients for refrigerant R22 and for four nonazeotropic mixtures of refrigerants R143a and R124 were measured and are presented as a function of mass flux for two inside tube surfaces, one having spiral ridged fins and the other having a spirally corrugated or fluted surface. The total condensing coefficient for the finned tube is higher than that for the fluted tube at any given refrigerant mass flux for all the refrigerant mixtures. The measured irrecoverable pressure drop for the finned tube was approximately half that for the fluted tube; thus, the finned tube has the better thermal performance of the two enhanced tubes. The condensing heat transfer coefficient is also presented as a function of the mass fraction of R143a for three values of mass flux. Degradation of the condensing coefficient for intermediate values of R143a mass fraction is apparent, but has different trends with respect to mass flux for the two enhanced surfaces; thus, the geometry of the enhanced surface appears to affect the physical mechanism for condensation of NARMs. 13 refs., 9 figs.

  11. Tubeside evaporation of nonazeotropic refrigerant mixtures from two enhanced surfaces

    SciTech Connect

    Conklin, J.C.; Vineyard, E.A.

    1990-01-01

    As part of the Building Equipment Research program at Oak Ridge National Laboratory, nonazeotropic refrigerant mixtures (NARMs) are being investigated to replace chlorofluorocarbon compounds. The evaporation of NARMs is not isothermal, and this can improve the heat exchanger effectiveness of an evaporator as well as improve thermodynamic cycle efficiencies. The evaporating heat transfer coefficient for four nonazeotropic mixtures of refrigerants R143a and R124 was investigated for two inside tube surfaces, one having spiral ridged fins and the other a corrugated or fluted surface. Refrigerant R22 was also evaporated for comparison of the finned and fluted enhanced surface performances. The measured pressure drop and the heat transfer coefficient for the complete evaporation from 25% quality to a slight amount of superheat of the NARMs and R22 are presented as a function of mass flux for both enhanced surfaces. Both the heat transfer coefficient and the pressure drop of the fluted tube are higher than those of the finned tube at both a given refrigerant mass flux and a given heat exchanger load for all the refrigerant mixtures. When plotted as a function of the mass fraction of R143a, the heat transfer coefficient for the fluted tube is minimal at approximately 40% (51% by mole) by mass of R143a. However, the heat transfer coefficient for the finned tube did not show a degradation as a function of R143a mass fraction, and it appears to be a linear function of the mass fraction of R143a for a given mass flux. 10 refs., 9 figs.

  12. A new evaluation method for zeotropic refrigerant mixtures based on the variance of the temperature difference between the refrigerant and heat transfer fluid

    Microsoft Academic Search

    Xing Jin; Xiaosong Zhang

    2011-01-01

    Compared to the pure refrigerants, the zeotropic refrigerant mixtures have the obvious temperature glide during phase change. Therefore, the Lorenz cycle can be approached with this special attribute. By analysing the heat transfer in the counter flow heat exchanger, a new evaluation method for zeotropic refrigerant mixtures based on the variance of the temperature difference between the refrigerant and heat

  13. Investigations of pool boiling heat transfer of binary refrigerant mixtures

    SciTech Connect

    Chiou, C.B. [Teco Electric and Machinery Co., Ltd., Tao-Yuan (Taiwan, Province of China); Lu, D.C. [National Chiao Tung Univ., Hsinchu (Taiwan, Province of China). Dept. of Mechanical Engineering; Wang, C.C. [Industrial Technology Research Inst., Hsinchu (Taiwan, Province of China). Energy and Research Labs.

    1997-07-01

    Pool boiling data for binary mixtures of R-22/R-124 on plain tubes are reported at reduced pressures of 0.1, 0.15, and 0.2. Significant reductions of heat transfer coefficients for mixtures are found as compared to pure refrigerant, and the reduction of heat transfer coefficient is especially pronounced in the vicinity of the pure component. This phenomenon is strongly related to the nonlinear variation of physical properties of liquid viscosity and latent heat of the mixtures. The available empirical and semiempirical correlations developed for mixtures are compared with the present data. In addition, a correlation based on the present R-22/R-124 experimental data is proposed. This correlation not only predicts the deterioration of heat transfer coefficients for the present data with success but also predicts the experimental data from other investigators with reasonably good accuracy.

  14. Evaluation of nonazeotropic refrigerant mixtures for capacity modulation

    SciTech Connect

    Vineyard, E.A.; Sand, J.R.

    1988-01-01

    A test program is underway at the Oak Ridge National Laboratory (ORNL) to evaluate the potential performance improvements from using nonazeotropic refrigerant mixtures in residential heat pumps. The goals of the research effort are to achieve (1) capacity control by adjusting the composition, (2) increased capacity, relative to R22, at low ambient temperatures, and (3) matching of the refrigerant temperature differentials to the source and sink fluid temperature differentials. Performance improvements are expected to result from decreasing the cycling losses and the amount of resistance heat required at low ambient temperatures along with reducing the irreversibilities in the heat exchangers. Initial results for a mixture of R13B1/R152a show a potential capacity modulation from 12431 Btu/h (3643 W) at 17 F (/minus/8.3/degree/C) to 8550 Btu/h (2506 W) at 47 F (8.3/degree/C) in heating and from 7451 Btu/h (2184 W) at 82 F (27. 8/degree/C) to 9188 Btu/h (2693 W) at 95 F (35/degree/C) in cooling. Other refrigerant pairs which are safer from an ozone depletion standpoint are under consideration for later testing. 10 refs., 5 figs., 4 tabs.

  15. Performance analysis of the natural mixture R744\\/R600a refrigeration cycle

    Microsoft Academic Search

    Xianping Zhang; Aidong Chen; Huanlin Duan

    2010-01-01

    Environmental conservation issue advances the refrigerant substitute for the Freons. Natural working fluid must be a perfect choice. Therefore, natural friendly refrigerants R744 and R600a are selected in this research to be a binary mixture. Such a mixture can weaken their shortcomings by decreasing high heat rejection pressure as that of pure R744, and reducing flammability as that of pure

  16. Evaluation of non-azeotropic mixtures containing HFOs as potential refrigerants in refrigeration and high-temperature heat pump systems

    Microsoft Academic Search

    ShengJun Zhang; HuaiXin Wang; Tao Guo

    2010-01-01

    With the increasing environmental concern on global warming, hydrofluoro-olefin (HFOs), possessing low GWP, has attracted\\u000a great attention of many researchers recently. In this study, non-azeotropic mixtures composed of HFOs (HFO-1234yf, HFO-1234ze(z),\\u000a HFO-1234ze(e) and HFO-1234zf) are developed to substitute for HFC-134a and CFC-114 in air-conditioning and high-temperature\\u000a heat pump systems, respectively. The cycle performances were evaluated by an improved theoretical cycle

  17. Laboratory evaluation of an ozone-safe nonazeotropic refrigerant mixture in a Lorenz-Meutzner refrigerator freezer design

    SciTech Connect

    Sand, J.R.; Vineyard, E.A.; Baxter, V.D.

    1992-11-01

    The Lorenz-Meutzner refrigerator freezer (RF) circuit has been proposed as a design which would operate with nonazcotropic refrigerant mixtures (NARMS) and significantly increase the thermodynamic efficiency of household refrigerators. Several ozone-safe and more environmentally acceptable refrigerants are known which could be blended into a NARM to replace R-12 for this domestic refrigeration application. Laboratory tests were performed on a Lorenz-Meutzner (L-M) RF using an R-32/R-124 NARM. Comparisons are made between the baseline performance of the refrigerator with R-12 before it was modified to the L-Ni design and that of the L-M circuit operating with R-12 and the NARM. Circuiting and component changes resulting from initial testing of this unit are described. Computer modeling and compressor calorimeter results for R-12 and the NARM used in the test unit are also presented. Small performance gains ({approx} 3%) are seen for the NARM over R-12 in the same refrigerator freezer circuit. Modeling results and steady-state data suggest larger improvements ({approx} 15%) are possible. It is felt that the larger improvements predicted from modeling and compressor calorimetry data are not being realized due to poor heat transfer and refrigerant circuiting arrangements.

  18. Laboratory evaluation of an ozone-safe nonazeotropic refrigerant mixture in a Lorenz-Meutzner refrigerator freezer design

    SciTech Connect

    Sand, J.R.; Vineyard, E.A.; Baxter, V.D.

    1992-01-01

    The Lorenz-Meutzner refrigerator freezer (RF) circuit has been proposed as a design which would operate with nonazcotropic refrigerant mixtures (NARMS) and significantly increase the thermodynamic efficiency of household refrigerators. Several ozone-safe and more environmentally acceptable refrigerants are known which could be blended into a NARM to replace R-12 for this domestic refrigeration application. Laboratory tests were performed on a Lorenz-Meutzner (L-M) RF using an R-32/R-124 NARM. Comparisons are made between the baseline performance of the refrigerator with R-12 before it was modified to the L-Ni design and that of the L-M circuit operating with R-12 and the NARM. Circuiting and component changes resulting from initial testing of this unit are described. Computer modeling and compressor calorimeter results for R-12 and the NARM used in the test unit are also presented. Small performance gains ({approx} 3%) are seen for the NARM over R-12 in the same refrigerator freezer circuit. Modeling results and steady-state data suggest larger improvements ({approx} 15%) are possible. It is felt that the larger improvements predicted from modeling and compressor calorimetry data are not being realized due to poor heat transfer and refrigerant circuiting arrangements.

  19. Boiling Heat Transfer and Pressure Drop of Non-Azeotropic Mixtures Inside a Horizontal Grooved Tube

    NASA Astrophysics Data System (ADS)

    Kajikawa, Satoru; Ayukawa, Kyozo; Sogo, Motosuke; Okita, Yuji

    The evaporation of HCFC141b, HFC152a and HFC23, and non-azeotropic refrigerant mixture used at the very low temperature refrigeration system is experimentally studied in a horizontal spirally grooved tube with corrugation. The experiments were conducted at 0.03 to 0.47MPa of boiling pressure, 100 kg/(m2s) of mass flux, 1 to 15 kW/ m2 of heat flux, -26 to 21 °C of refrigerant temperature and 11.4 mm of average inner diameter. It is concluded that boiling heat transfer coefficients of single-refrigerant are higher than these of non-azeotropic refrigerant mixture. And dimensionless correlation of the heat transfer coefficirnts, i.e. Lockhart-Martinelli parameters agreed with equation (10) within the limit of ±40 percent. Pressure drops of these refrigerant mixture depend on its liquid density and flow pattern.

  20. Viscosity measurements and correlations of binary mixtures: 1,1,1,2-tetrafluoroethane (HFC134a) + tetraethylene glycol dimethylether (TEGDME)

    Microsoft Academic Search

    M. A. Monsalvo; A. Baylaucq; P. Reghem; S. E. Quiñones-Cisneros; C. Boned

    2005-01-01

    This paper reports viscosity data for the binary system1,1,1,2-tetrafluoroethane (HFC-134a), x1, +tetraethylene glycol dimethylether (TEGDME), 1?x1. The measurements (200 data points) were obtained at various pressures (between 10 and 100MPa) in the homogeneous liquid state from T=293.15–373.15K. The measurements have been carried out with a falling body viscometer for four molar fractions x1=(0.28, 0.44, 0.63 and 0.88). The density values

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

    Microsoft Academic Search

    Douglas G. Westra

    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

  2. Experimental study of the refrigeration cycle performance for the R744\\/R290 mixtures

    Microsoft Academic Search

    Baolian Niu; Yufeng Zhang

    2007-01-01

    A new binary mixture of R744 and R290 as an alternative natural refrigerant to R13 was first presented in this paper. Its environmental performance is friendly. It has an ODP of zero and GWP smaller than 20. Experimental studies for this mixture and R13 were performed on a cascade refrigeration system only with modification to capillary in low-temperature circuit. COP

  3. Heat exchanger thermal performance for two nonazeotropic refrigerant mixtures

    SciTech Connect

    Conklin, J.C.; Vineyard, E.A.

    1991-08-15

    Two nonazeotropic refrigerant mixtures (NARMs), the first consisting of 71% R22 and 29% R114 and the second consisting of 75% R143a and 25% R124 (approximate percentages by mass), were studied at various mass flow rate and heat loads in an experimental apparatus at Oak Ridge National Laboratory. The measured thermal performance of the evaporator and the condenser are presented in terms of the number of transfer units (NTU) and effectiveness ({epsilon}). Because the phase-change process of the NARMS is nonisothermal, a specific heat for the two-phase region can be defined. This two-phase specific heat for the NARMs varies with respect to enthalpy. Because the standard NTU-{epsilon} analysis is valid only for constant specific heat fluids, and analysis that considers variable specific heat fluids is used to compare analytical predictions of the thermal performance with the observed thermal performance. The predicted and measured results show very good agreement when the pressure drop is low. 6 refs., 4 figs., 4 tabs.

  4. Experimental investigation on mixed refrigerant Joule-Thomson cryocooler with flammable and non-flammable refrigerant mixtures

    NASA Astrophysics Data System (ADS)

    Walimbe, N. S.; Narayankhedkar, K. G.; Atrey, M. D.

    2010-10-01

    The mixed refrigerant Joule-Thomson (MR J-T) cryocoolers have a wide application area covering the temperature range from 80 K to 200 K. The significant advantages of the system are simplicity of its design and working reliability with high level performance. The present paper discusses the experimental results of MR J-T cooler with different flammable and non-flammable mixture compositions. The work highlights the use of pressure-enthalpy and temperature-enthalpy diagrams for these mixtures to support the experimental results. A record lowest temperature of 65 K and a cooling capacity of 6 W at 80 K are obtained for a single stage MR J-T system starting at 300 K. Further, using a mixture of minimum flammable refrigerants, temperatures below 100 K is achieved.

  5. TRANSPORT PROPERTY MEASUREMENTS OF HFC-236EA

    EPA Science Inventory

    The report gives results of an evaluation of transport properties of 1,1,1,2,3,3,-hexafluoropropane (HFC-236ea), with liquid viscosity and thermal conductivity being the two main transport properties of interest. In addition, the specific heat and density of refrigerant/lubrican...

  6. TRANSPORT PROPERTY MEASUREMENTS OF HFC-236EA

    EPA Science Inventory

    The report gives results of an evaluation of transport properties of 1, 1, 1, 2, 3, 3-hexafluoropropane (HFC-236ea), with liquid viscosity and thermal conductivity being the two main transport properties of interest. In addition, the specific heat and density of refrigerant/lubri...

  7. Thermodynamic Properties of the Mixtures R23\\/R744 and R41\\/R744 and their Efficiency as Refrigerants

    Microsoft Academic Search

    Aleksandr Vasserman C; Valentine Malchevsky S

    Mixtures of refrigerants are widely used as working substances for refrigerating plants. Among them, mixtures of ozone-safe and natural refrigerants, in particular R23\\/R744 and R41\\/R744, are important. For calculating their thermodynamic properties, we compiled equations of state on the basis of the method in (1). According to this reference, the equation of state for a mixture is presented as a

  8. FLAME SUPPRESSION AND LUBRICANT INTERACTION OF HYDROCARBON MIXTURES FOR HOUSEHOLD REFRIGERANT/FREEZERS

    EPA Science Inventory

    The paper discusses the flame suppression and lubricant interaction of hydrocarbon (HC) mixtures for household refrigerator/freezers (R/Fs). he work focuses on blending the minimum amount of a fluoroiodocarbon (FIC) with previously optimized R/F-tested HC mixtures to reduce their...

  9. Experimental investigation on mixed refrigerant Joule–Thomson cryocooler with flammable and non-flammable refrigerant mixtures

    Microsoft Academic Search

    N. S. Walimbe; K. G. Narayankhedkar; M. D. Atrey

    2010-01-01

    The mixed refrigerant Joule–Thomson (MR J–T) cryocoolers have a wide application area covering the temperature range from 80K to 200K. The significant advantages of the system are simplicity of its design and working reliability with high level performance. The present paper discusses the experimental results of MR J–T cooler with different flammable and non-flammable mixture compositions. The work highlights the

  10. Thermodynamic Correlations, k - Exponents, Speed of Sound, and COP Data for Binary Refrigerant Mixtures

    Microsoft Academic Search

    A. Stegou-Sagia; M. Damanakis

    2004-01-01

    Our study covers thermodynamic performance quantities for binary refrigerant mixtures of R-32\\/R-134a with compositions of 20\\/80%, 30\\/70%, 40\\/60% by mass for a wide range of thermodynamic conditions (pressure: 0.2 - 3.0 MPa, temperature: 240 - 480 o K and saturated conditions). The primary thrust of the study is the calculation of coefficient of performance (COP) values for refrigeration systems. Additional

  11. Accelerated screening methods for determining chemical and thermal stability of refrigerant-lubricant mixtures: Part 2, Experimental comparison and verification of methods. Quarterly technical progress report, 1 July 1993--30 September 1993

    SciTech Connect

    Kauffman, R.

    1993-12-01

    Research reported continued to concentrate on in situ conductivity measurements for development of an accelerated screening method for determining the chemical and thermal stabilities of refrigerant/lubricant mixtures. Tungsten rods were sealed into the round bottoms of the sealed tubes to provide electrical connections for in situ conductivity measurements. The in situ conductivity measurements were used to monitor the degradation of HFC-134a/ester oil mixtures heated at 175 C (347 F) for two days. Preliminary results indicate that the in situ conductivity measurements correlate with H-1 34a/oil degradation as determined by color measurements. A short study to evaluate the potential of in situ color measurements for development into an accelerated screening test was also performed. Initial results indicate that the in situ color measurements are not well suited for long-term, in situ degradation measurements.

  12. IMPROVING THE ENERGY EFFECTIVENESS OF DOMESTIC REFRIGERATORS BY THE APPLICATION OF REFRIGERANT MIXTURES*

    E-print Network

    Oak Ridge National Laboratory

    . A temperature-concentration diagram of an ideal binary solution at a given pressure has the characteristics the compressor discharge to the expansion device inlet, and the low-pressure level from the expansion device outlet to the compressor inlet. Inthe cycle of Figs. 4 and 5, it is assumed that refrigerant leaves

  13. Accelerated screening methods for determining chemical and thermal stability of refrigerant-lubricant mixtures, Part 1: Method assessment. Final report

    SciTech Connect

    Kauffman, R.

    1993-04-01

    This report presents results of a literature search performed to identify analytical techniques suitable for accelerated screening of chemical and thermal stabilities of different refrigerant/lubricant combinations. Search focused on three areas: Chemical stability data of HFC-134a and other non-chlorine containing refrigerant candidates; chemical stability data of CFC-12, HCFC-22, and other chlorine containing refrigerants; and accelerated thermal analytical techniques. Literature was catalogued and an abstract was written for each journal article or technical report. Several thermal analytical techniques were identified as candidates for development into accelerated screening tests. They are easy to operate, are common to most laboratories, and are expected to produce refrigerant/lubricant stability evaluations which agree with the current stability test ANSI/ASHRAE (American National Standards Institute/American Society of Heating, Refrigerating, and Air-Conditioning Engineers) Standard 97-1989, ``Sealed Glass Tube Method to Test the Chemical Stability of Material for Use Within Refrigerant Systems.`` Initial results of one accelerated thermal analytical candidate, DTA, are presented for CFC-12/mineral oil and HCFC-22/mineral oil combinations. Also described is research which will be performed in Part II to optimize the selected candidate.

  14. Nucleate boiling heat transfer coefficients of pure halogenated refrigerants

    Microsoft Academic Search

    Dongsoo Jung; Youngil Kim; Younghwan Ko; Kilhong Song

    2003-01-01

    Nuclate pool boiling heat transfer coefficients (HTCs) of HCFC123, CFC11, HCFC142b, HFC134a, CFC12, HCFC22, HFC125 and HFC32 on a horizontal smooth tube of 19.0 mm outside diameter have been measured. The experimental apparatus was specially designed to accomodate high vapor pressure refrigerants such as HFC32 and HFC125 with a sight glass. A cartridge heater was used to generate uniform heat

  15. Thermodynamic performance of HCFC22 alternative refrigerants for residential air-conditioning applications

    Microsoft Academic Search

    Ki-Jung Park; Dongsoo Jung

    2007-01-01

    In this study, thermodynamic performance of two pure hydrocarbons and seven mixtures composed of propylene (R1270), propane (R290), HFC152a, and dimethylether (RE170, DME) was measured in an attempt to substitute HCFC22 in residential air-conditioners. The pure and mixed refrigerants tested have greenhouse warming potentials (GWPs) of 3–58 as compared to that of CO2 and the mixtures are all near-azeotropic having

  16. A Non-Flammable, Reduced GWP, HFC134a Replacement in Centrifugal Chillers: DR11

    Microsoft Academic Search

    Konstantinos Kontomaris; Thomas J. Leck; Joshua Hughes

    2010-01-01

    Air conditioning in large buildings is often provided by centrifugal chillers using HFC-134a. Efforts to mitigate climate change are motivating the identification of HFC replacements with low GWPs. HFO-1234yf, with a GWP100=4, has been found promising as an HFC-134a replacement in centrifugal chillers (Kontomaris et al., 2010). However, HFO-1234yf is marginally (ASHRAE 2L) flammable. A new non-flammable developmental refrigerant, DR-11,

  17. Thermodynamic Estimation Method of Ternary Refrigerant Mixtures Using New Mixing Rules

    NASA Astrophysics Data System (ADS)

    Yoshida, Yuji; Kodama, Hisasi; Funakura, Masami; Arita, Koji

    Binary and ternary refrigerant mixtures are attracting attentions in view of the energy saving and the ozone problem. This paper proposes modified mixing rules of two-constant (a,b) cubic equation of state for ternary mixtures. The addition of the ternary interaction parameter c123 to the mixing rule, occurring in conjunction with the parameter b,was examined in the calculation of thermodynamic properties in comparison with common mixing rules. The validity of new mixing rules was evaluated by using literary vapor-liquid equilibrium date of ternary refrigerant mixtures i. e. R14-R23-R13,R13B1-R12-R152a,R22-R12-R114,R290-R22-R115 and R12-R152a-R113. It was found that the ternary interaction parameter C123 contributes to the accuracy of the vapor pressure and is almost equal irrespective to the measured temperature. The three-dimensional representation system of the phase diagram of ternary refrigerant mixtures was also developed in order to decide compositions of alternative mixtures.

  18. The Effect of Circuiting Arrangement on the Thermal Performance of Refrigeration Mixtures in Tube-and-Fin Condensing Heat Exchangers

    Microsoft Academic Search

    D. T. Chen; J. C. Conklin

    1999-01-01

    For the pure or azeotropic refrigerants typically used in;\\u000apresent air conditioning and refrigeration applications, the;\\u000arefrigerant changes phase at a constant temperature. Thus, the;\\u000arefrigerant circuiting arrangement such as crossfiow,;\\u000acounterfiow, or cross-counterflow, has no effect on the thermal;\\u000aperformance. For zeotropic refrigerant mixtures, however, the;\\u000aphase-change occurs over a temperature range, or \\

  19. Theoretical and experimental investigation of the interaction between refrigerant mixtures and moist air in air conditioning application

    Microsoft Academic Search

    Chwalowski

    1991-01-01

    The design of the heat exchanger utilizing nonazeotropic refrigerant in an air conditioning application presents unique problems due to the phase change of the moist air and the variable specific heat of the evaporating refrigerant mixture. This study discusses the performance analysis and the design procedure of a cross counterflow heat exchanger working as an evaporator in an experimental system

  20. Cycle performance comparison between a nonazeotropic refrigerant mixture and R22

    SciTech Connect

    Vineyard, E.A.; Conklin, J.C.

    1991-01-01

    In an effort to improve the efficiency of residential heat pumps and reduce the ozone depletion potential (ODP) of the refrigerant, nonazeotropic mixtures (NARMs) are being investigated as part of the Building Equipment Research program at Oak Ridge National Laboratory (ORNL). One of the NARMs, a mixture consisting of approximately 75% R143a and 25% R124 (percentages by mass) was tested over a range of mass flow rates at Department of Energy (DOE) heat pump rating conditions (27.8 {degrees}C cooling). Since NARMs exhibit an inherent decrease in the heat transfer coefficient relative to pure refrigerants, three refrigerant-side enhancements were tested to determine if overall system performance could be improved. In addition to the performance of the NARM, performance for the tube surfaces with R22 was measured to determine any benefits from the nonisothermal phase-change process characteristic of NARMs. Comparisons were made on the basis of the coefficient of performance (COP) as a function of capacity. The conclusion was that refrigerant-side heat transfer enhancements improved the COP of the NARM-operated system more than that of the R22-operated system. 7 refs., 6 figs.

  1. Thermal Conductivity of Nonazeotropic Gaseous Mixtures of Fluorocarbon Refrigerants

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshiyuki; Ueno, Hiroshi; Kubota, Hironobu; Makita, Tadashi

    The thermal conductivity of four binary gaseous mixtures of R22 (CHCIF2) with R13(CClF3), R23(CHF3), R12(CCl2F2) and R114(CClF2·CClF2) has been measured at temperatures 298.15 and 323.15K under pressures from atmospheric to saturated pressures by a coaxial cylinder cell. The precision of the thermal conductivity obtained is within 2%. The thermal conductivity of mixtures increases with increasing temperature and pressure at a constant composition. The thermal conductivity in each mixture changes almost linearly with the concentration of R22 at a constant temperature and pressure, although the thermal conductivity at each composition is slightly larger than the calculated values by a simple molefraction average method. The experimental results were correlated with composition and pressure by empirical equations and compared with several kinds of prediction methods. The Brokaw's equation is found to reproduce the experimental data most successfully with a mean deviation of 0.7%.

  2. Energy and exergy analysis of new refrigerant mixtures in an Organic Rankine Cycle for low temperature power generation

    Microsoft Academic Search

    S. M. Sami

    2010-01-01

    This paper presents and discusses the performance of environmentally-friendly refrigerant mixtures in an Organic Rankine Cycle (ORC) for power generation. The performance has been compared at low and medium waste heat temperatures to other organic and non-organic fluids.The refrigerant mixtures boil at extremely low temperatures and are capable of efficiently capturing waste heat at temperatures less than 27°C (80°F). The

  3. Chemical and thermal stability of refrigerant-lubricant mixtures with metals. Final report

    SciTech Connect

    Huttenlocher, D.F.

    1992-10-09

    This report presents the results of a sealed tube stability study on twenty-one refrigerant-lubricant mixtures selected from the following groupings: HFCs R-32, R-125, R-134, R-134a, R-143a, and R-152a with one or more lubricants selected from among three pentaerythritol esters and three polyalkylene glycols. All lubricants were carefully predried to 25 ppm or less moisture content. HCFCs R-22, R-123, R-124, and R-142b, as well as CFC R-11, with one or more lubricants selected from among two mineral oils and one alkylbenzene fluid. Bach test mixture was aged at three temperature levels.

  4. Chemical and thermal stability of refrigerant-lubricant mixtures with metals

    SciTech Connect

    Huttenlocher, D.F.

    1992-10-09

    This report presents the results of a sealed tube stability study on twenty-one refrigerant-lubricant mixtures selected from the following groupings: HFCs R-32, R-125, R-134, R-134a, R-143a, and R-152a with one or more lubricants selected from among three pentaerythritol esters and three polyalkylene glycols. All lubricants were carefully predried to 25 ppm or less moisture content. HCFCs R-22, R-123, R-124, and R-142b, as well as CFC R-11, with one or more lubricants selected from among two mineral oils and one alkylbenzene fluid. Bach test mixture was aged at three temperature levels.

  5. Compatibility of refrigerants and lubricants with motor materials

    SciTech Connect

    Doerr, R.; Kujak, S.

    1992-10-01

    During the compatibility study of 10 pure refrigerants with 24 motor materials, it was observed that the greatest damage to the insulation system was caused by absorption of refrigerant followed by rapid desorption. The observed effects were blisters, cracking, internal bubbles and delamination. Measured results includes decreased bond strength, dielectric strength and overall integrity of the material. Refrigerants HCFC-22, HFC-32, HFC-134 and HFC-152a exhibited this phenomena. The effect of HCFC-22 was most severe of the tested refrigerants. Since HCFC-22 has an excellent reliability history with many of the materials tested, compatibility with the new refrigerants is expected.

  6. Influence of nucleation on the flow boiling heat transfer coefficient of a refrigerant mixture under varied heat flux conditions

    Microsoft Academic Search

    B. Raja; D. K. Kumar; D. M. Lal; R. Saravanan

    2009-01-01

    The influence of nucleation on the flow boiling heat transfer coefficient of R-134a\\/R-290\\/R-600a refrigerant mixture is experimentally\\u000a studied in a smooth horizontal tube of 12.7 mm diameter. The heat transfer coefficients are experimentally measured for stratified\\u000a flow patterns under a varied heat flux condition; a condition found in the evaporator of refrigerators and deep freezers.\\u000a The experiments are conducted in

  7. Occupational exposure to fluorinated hydrocarbons during refrigeration repair work.

    PubMed

    Gjølstad, Merete; Ellingsen, Dag G; Espeland, Oscar; Nordby, Karl-Christian; Evenseth, Harald; Thorud, Syvert; Skaugset, Nils Petter; Thomassen, Yngvar

    2003-04-01

    This study describes refrigeration repair workers' occupational exposures to halogenated refrigerants, focusing on difluorochloromethane (HCFC 22), tetrafluoroethane (HFC 134a) and a mixture of tri-, tetra- and pentafluoroethane (R404A) in 30 work operations. Unlike earlier reported studies, the present study includes working procedures involving welding in order to measure possible occupational exposure to decomposition products. The measurements included hydrogen fluoride (HF), hydrogen chloride (HCl), phosgene (COCl2) and volatile organic compounds (VOC). The exposures were assessed during work operations on small-scale cooling installations like refrigerators and freezers. The repair workers' occupational exposures to refrigerants were moderate, and the major part of the exposures were associated with specific working procedures lasting for relatively short periods of time (<20 min). During these exposure events the concentrations were occasionally high (up to 42434 mg m(-3)). Although welding operations lasted only for short periods of time, HF was detected in 9 out of 15 samples when HCFC 22, HFC 134a or R404A had been used. Hydrogen chloride was detected in 3 out of 5 samples in air polluted with HCFC 22. Phosgene was not detected. A large number of VOCs in various concentrations were found during welding. Except for the applied refrigerants, halogenated compounds were only found in one sample. PMID:12729261

  8. Accelerated test methods for predicting the life of motor materials exposed to refrigerant/lubricant mixtures. Phase 1, Conceptual design: Final report

    SciTech Connect

    Ellis, P.F. II; Ferguson, A.

    1993-08-18

    The federally mandated phase-out of chlorofluorocarbon refrigerants requires screening tests for motor materials compatibility with alternative refrigerant/lubricant mixtures. In the current phase of the program, ARTI is supporting tests of promising candidate refrigeration/lubricant systems in key refrigeration component systems such as bearings and hermetic motor insulation systems to screen for more subtle detrimental effects and allow estimates of motor-compressor life. This report covers: mechanisms of failure of hermetic motor insulation, current methods for estimation of life of hermetic motors, and conceptual design of improved stator simulator device for testing of alternative refrigerant/lubricant mixtures.

  9. COMPARISON OF CFC-114 AND HFC-236EA PERFORMANCE IN SHIPBOARD VAPOR COMPRESSION SYSTEMS

    EPA Science Inventory

    The report gives results of a comparison of the performance of two refrigerants - 1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and 1,2-dichloro-tetrafluoroethane (CFC-114) - in shipboard vapor compression refrigeration systems. (NOTE: In compliance with the Montreal Protocol and Dep...

  10. Blends of carbon dioxide and HFCs as working fluids for the low-temperature circuit in cascade refrigerating systems

    Microsoft Academic Search

    Giovanni Di Nicola; Giuliano Giuliani; Fabio Polonara; Roman Stryjek

    2005-01-01

    This paper describes an analysis on the performances of a cascade refrigeration cycle operated with blends of carbon dioxide (CO2, or R744) and hydrofluorocarbons (HFC) as the low-temperature working fluid. The aim of this work was to study the possibility of using carbon dioxide mixtures in those applications where temperatures below CO2 triple point (216.58K) are needed. The analysis was

  11. Solubility, viscosity and density of refrigerant/lubricant mixtures. Final technical report, [1 October 1992--19 April 1994

    SciTech Connect

    Henderson, D.R.

    1994-04-01

    This report presents the results of experimental measurements on low refrigerant concentration mixtures (0, 10, 20 and 30 weight percent) and high refrigerant concentration mixtures (80, 90 and 100 weight percent) of chlorofluorocarbon (CFC) 12, hydrochlorofluorocarbons (HCFC`s) 22, 123, 124 and 142b, and hydrofluorocarbons (BFC`s) 134a, 32, 125, 152a and 143a with mineral oil, alkylbenzene, polyalkylene glycol and polyolester lubricants. Viscosity, solubility (vapor pressure) and density data are reported for thirty five working fluids which are selected combinations of these refrigerants and companion lubricants. These data, reduced to engineering form, are presented in the form of a Daniel Chart and a plot of density versus temperature and composition. Extensive numerical analysis has been performed in order to derive equations which allow two independent variables (temperature and composition) and to provide for corrections in composition due to vapor space volume in the test apparatus.

  12. Phase Diagram Calculation of Gas Mixtures for Refrigeration; Reflection & Transmission Coefficients and the Effective Mass: Superconducting Proximity IV Measurements

    Microsoft Academic Search

    Gideon Friedmann

    1996-01-01

    The efficiency of Joule-Thomson refrigerators greatly improves with the addition of hydrocarbons to nitrogen as coolant, and is highly dependent on the mixture composition. To optimize it, we calculated the mixture phase diagram using the Peng-Robinson equation of state. A program was developed to solve numerically a set of coupled non-linear equations for the equilibrium of the vapor and liquid

  13. (Discussion of domestic refrigerator/freezer (R/F) design for nonazeotropic refrigerant mixtures (NARMs), Hannover, W. Germany, and visit to Kassel, W. Germany, May 2--5, 1989): Foreign trip report

    SciTech Connect

    Sand, J.R.; Vineyard, E.A.

    1989-05-18

    The purpose of this trip was to meet with Dr. H. Kruse at the University of Hannover and discuss a domestic refrigerator/freezer (R/F) design for nonazeotropic refrigerant mixtures (NARMs), inspect a R/F modified to work with NARMs, and acquire the rational and computer codes for modeling NARM R/F performance for this design.

  14. Analysis of the gas compressibility effects on the constant-entropy reversible processes of refrigerants and refrigerant mixtures

    Microsoft Academic Search

    F. de Monte

    2002-01-01

    Thermally and calorically real gas modelling based on the Martin–Hou equation of state is assumed for pure and mixed refrigerants in the superheated vapour phase. It allows the constant-entropy reversible processes which take place within the work transfer components of ideal vapour compression cycles to be properly analysed. These processes, in fact, occur in a region of the Mollier diagram

  15. Theoretical analysis for condensation heat transfer of binary refrigerant mixtures with annular flow in horizontal mini-tubes

    NASA Astrophysics Data System (ADS)

    Zhang, Hui-Yong; Li, Jun-Ming; Sun, Ji-Liang; Wang, Bu-Xuan

    2015-06-01

    A theoretical model is developed for condensation heat transfer of binary refrigerant mixtures in mini-tubes with diameter about 1.0 mm. Condensation heat transfer of R410A and R32/R134a mixtures at different mass fluxes and saturated temperatures are analyzed, assuming that the phase flow pattern is annular flow. The results indicate that there exists a maximum interface temperature at the beginning of condensation process for azeotropic and zeotropic mixtures and the corresponding vapor quality to the maximum value increases with mass flux. The effects of mass flux, heat flux, surface tension and tube diameter are analyzed. As expected, the condensation heat transfer coefficients increase with mass flux and vapor quality, and increase faster in high vapor quality region. It is found that the effects of heat flux and surface tension are not so obvious as that of tube diameter. The characteristics of condensation heat transfer of zeotropic mixtures are consistent to those of azeotropic refrigerant mixtures. The condensation heat transfer coefficients increase with the concentration of the less volatile component in binary mixtures.

  16. Human safety and pharmacokinetics of the CFC alternative propellants HFC 134a (1,1,1,2-tetrafluoroethane) and HFC 227 (1,1,1,2,3,3, 3-heptafluoropropane) following whole-body exposure.

    PubMed

    Emmen, H H; Hoogendijk, E M; Klöpping-Ketelaars, W A; Muijser, H; Duistermaat, E; Ravensberg, J C; Alexander, D J; Borkhataria, D; Rusch, G M; Schmit, B

    2000-08-01

    HFC 134a (1,1,1,2-tetrafluoroethane) and HFC 227 (1,1,1,2,3,3, 3-heptafluoropropane) are used to replace chlorofluorocarbons (CFCs) in refrigerant and aerosol applications, including medical use in metered-dose inhalers. Production and consumption of CFCs are being phased out under the Montreal Protocol on Substances that Deplete the Ozone Layer. The safety and pharmacokinetics of HFC 134a and HFC 227 were assessed in two separate double-blind studies. Each HFC (hydrofluorocarbon) was administered via whole-body exposure as a vapor to eight (four male and four female) healthy volunteers. Volunteers were exposed, once weekly for 1 h, first to air and then to ascending concentrations of HFC (1000, 2000, 4000, and 8000 parts per million (ppm)), interspersed with a second air exposure and two CFC 12 (dichlorodifluoromethane) exposures (1000 and 4000 ppm). Comparison of either HFC 134a or HFC 227 to CFC 12 or air gave no clinically significant results for any of the measured laboratory parameters. There were no notable adverse events, there was no evidence of effects on the central nervous system, and there were no symptoms of upper respiratory tract irritation. HFC 134a, HFC 227, and CFC 12 blood concentrations increased rapidly and in an exposure-concentration-dependent manner, although not strictly proportionally, and approached steady state. Maximum blood concentrations (C(max)) tended to be higher in males than females; in the HFC 227 study, these were statistically significantly (P < 0. 05) higher in males for each HFC 227 and CFC 12 exposure level. In the HFC 134a study, the gender difference in C(max) was only statistically significant (P < 0.05) for CFC 12 at 4000 ppm and HFC 134a at 8000 ppm. Following the end of exposure, blood concentrations declined rapidly, predominantly biphasically and independent of exposure concentration. For the HFC 134a study, the t(1/2)alpha (alpha elimination half-life) was short for both CFC 12 and HFC 134a (<11 min). The t(1/2)beta (beta elimination half-life) across all exposure concentrations was a mean of 36 and 42 min for CFC 12 and HFC 134a, respectively. Mean residence time (MRT) was an overall mean of 42 and 44 min for CFC 12 and HFC 134a, respectively. In the HFC 227 study, t(1/2)alpha for both CFC 12 and HFC 227, at each exposure level, was short (<9 min) and tended to be lower in males than females. For CFC 12 mean t(1/2)beta ranged from 23 to 43 min and for HFC 227 the mean range was 19-92 min. The values tended to be lower for females than males for HFC 227. For both CFC 12 and HFC 227, MRT was statistically significantly lower (P < 0.05) in males than females and independent of exposure concentration. For CFC 12, MRT was a mean of 37 and 45 min for males and females, respectively, and for HFC 227 MRT was a mean of 36 and 42 min, respectively. Exposure of healthy volunteers to exposure levels up to 8000 ppm HFC 134a, 8000 ppm HFC 227, and 4000 ppm CFC 12 did not result in any adverse effects on pulse, blood pressure, electrocardiogram, or lung function. PMID:11029265

  17. Evaporation of nonazeotropic mixture of refrigerants R143a and R124 flowing inside smooth and corrugated tubes

    SciTech Connect

    Hinton, D.L. (Tennessee State Univ., Nashville, TN (United States)); Conklin, J.C.; Vineyard, E.A. (Oak Ridge National Lab., TN (United States))

    1992-01-01

    Because heat exchanger thermal performance has a direct influence on the overall cycle performance of vapor-compression refrigeration machinery, enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. We investigated a nonazeotropic refrigerant mixture (NARM) of 75% R143a and 25% R124 (by mass) to study its thermal performance in an evaporator made of conventional smooth tubes and another evaporator made of corrugated, or spirally indented, tubes. We investigated the evaporating heat transfer and pressure drop characteristics in an experimental test loop model of a domestic heat pump system employing a variable speed compressor. The refrigerant circulates inside the central tube and the water circulates in the annulus. At a refrigerant mass flux of approximately 328 kg/m{sup 2}s, the measured irreversible pressure drop of the corrugated surface was 100% higher than that of the smooth surface, and the measured heat transfer coefficient was 11% higher than that of the smooth surface.

  18. Evaporation of nonazeotropic mixture of refrigerants R143a and R124 flowing inside smooth and corrugated tubes

    SciTech Connect

    Hinton, D.L. [Tennessee State Univ., Nashville, TN (United States); Conklin, J.C.; Vineyard, E.A. [Oak Ridge National Lab., TN (United States)

    1992-08-01

    Because heat exchanger thermal performance has a direct influence on the overall cycle performance of vapor-compression refrigeration machinery, enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. We investigated a nonazeotropic refrigerant mixture (NARM) of 75% R143a and 25% R124 (by mass) to study its thermal performance in an evaporator made of conventional smooth tubes and another evaporator made of corrugated, or spirally indented, tubes. We investigated the evaporating heat transfer and pressure drop characteristics in an experimental test loop model of a domestic heat pump system employing a variable speed compressor. The refrigerant circulates inside the central tube and the water circulates in the annulus. At a refrigerant mass flux of approximately 328 kg/m{sup 2}s, the measured irreversible pressure drop of the corrugated surface was 100% higher than that of the smooth surface, and the measured heat transfer coefficient was 11% higher than that of the smooth surface.

  19. Thermophysical Properties of the Refrigerant Mixtures R417A and R417B from Dynamic Light Scattering (DLS)

    NASA Astrophysics Data System (ADS)

    Heller, A.; Rausch, M. H.; Flohr, F.; Leipertz, A.; Fröba, A. P.

    2012-03-01

    Dynamic light scattering (DLS) has been used for the measurement of several thermophysical properties of the refrigerant mixtures R417A (50 % by mass 1,1,1,2-tetrafluoroethane—R134a, 46.6 % pentafluoroethane—R125, 3.4 % n-butane—R600) and R417B (79 % by mass R125, 18.25 % R134a, 2.75 % R600). Both refrigerant mixtures are designed for a replacement of R22 (chlorodifluoromethane) in existing refrigeration systems. Thermal diffusivity and sound speed have been obtained by light scattering from the bulk fluid for the liquid phase under saturation conditions over a temperature range from about 283 K up to the liquid-vapor critical point with estimated uncertainties between 1 % and 3 % and between 0.5 % and 2 %, respectively. By applying the method of DLS to a liquid-vapor interface, also called surface light scattering, the saturated liquid kinematic viscosity and surface tension have been determined simultaneously. These properties have been measured from 253.15 K up to the liquid-vapor critical point with estimated uncertainties between 1 % and 3 % for kinematic viscosity and between 1 % and 2 % for surface tension. The measured thermal diffusivity, sound speed, kinematic viscosity, and surface tension are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with but always smaller than the uncertainties. The results are discussed in detail in comparison with literature data and with various prediction methods.

  20. Compatibility of refrigerants and lubricants with motor materials. Quarterly technical progress report, 1 July 1992--30 September 1992

    SciTech Connect

    Doerr, R.; Kujak, S.

    1992-10-01

    During the compatibility study of 10 pure refrigerants with 24 motor materials, it was observed that the greatest damage to the insulation system was caused by absorption of refrigerant followed by rapid desorption. The observed effects were blisters, cracking, internal bubbles and delamination. Measured results includes decreased bond strength, dielectric strength and overall integrity of the material. Refrigerants HCFC-22, HFC-32, HFC-134 and HFC-152a exhibited this phenomena. The effect of HCFC-22 was most severe of the tested refrigerants. Since HCFC-22 has an excellent reliability history with many of the materials tested, compatibility with the new refrigerants is expected.

  1. Two-Phase Flow of HCFC-22 and HFC-134a through Short Tube Orifices 

    E-print Network

    Yongchan, K.

    2008-01-23

    HCFC-22 and HFC-134a were used with short tube orifices having length to diameter ratios ranging from 5 to 20 in a 9.53 mm (3/8 in.) refrigerant line to investigate both two-phase and subcooled liquid flow entering the short tubes. Flow temperature...

  2. RETROFITTING AN AUTOMOTIVE AIR CONDITIONER WITH HFC-134A, ADDITIVE, AND MINERAL OIL

    EPA Science Inventory

    The paper gives results of an evaluation of a lubricant additive developed for use in retrofitting motor vehicle air conditioners. he additive was designed to enable HFC-134a to be used as a retrofit refrigerant with the existing mineral oil in CVC-12 systems. he goal of the proj...

  3. HEAT TRANSFER EVALUATION OF HFC-236EA AND CFC-114 IN CONDENSATION AND EVAPORATION

    EPA Science Inventory

    The report gives results of a heat transfer evaluation of the refrigerants hexafluoropropane (HFC-236ea) and 1,1,2,2-dichloro-tetrafluoroethane (CFC-114). (NOTE: With the mandatory phase-out of chlorofluorocarbons (CFCs), as dictated by the Montreal Protocol and Clean Air Act Ame...

  4. Performance comparison between alternative and phased-out refrigerants

    Microsoft Academic Search

    K. M. K. Abu-Abdou

    1994-01-01

    Three performance criteria of the ideal vapour-compression refrigeration cycle are selected to conduct a comparative study between the new HCFC refrigerant R-123 and the old CFC refrigerant R-11; and between the new HFC refrigerant R-134a and the old CFC refrigerant R-12. These performance criteria are the coefficient of performance (COP), the compressor's pressure ratio (PR) and the specific compressor's intake

  5. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  6. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  7. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  8. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  9. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  10. Energy and global warming impacts of next generation refrigeration and air conditioning technologies

    Microsoft Academic Search

    J. R. Sand; S. K. Fischer; V. D. Baxter

    1996-01-01

    Significant developments have occurred in hydrofluorocarbon (HFC) and the application of ammonia and hydrocarbons as refrigerant working fluids since the original TEWI (Total Equivalent Warming Impact) report in 1991. System operating and performance data on alternative refrigerants and refrigeration technologies justify and updated evaluation of these new alternative refrigerants and competing technologies in well-characterized applications. Analytical and experimental results are

  11. Acute neurobehavioral effects in rats from exposure to HFC 134a or CFC 12.

    PubMed

    Ritchie, G D; Kimmel, E C; Bowen, L E; Reboulet, J E; Rossi, J

    2001-04-01

    1,1,1,2-Tetrafluoroethane (HFC 134a), a chlorine-free hydrofluoroalkane, is internationally replacing billions of pounds of dichlorodifluoromethane (CFC 12) for coolant, refrigerant and aerosol propellant applications. The ALC50 for HFC 134a in rats is 567,000 ppm for 4 h; its potential for cardiac epinephrine sensitization in beagle dogs is acceptable (75,000 ppm); and its capacity to induce carcinogenicity or developmental disorders in animals is minimal. HFC 134a, with a serum half life estimated at 4-11 min, has been accepted for use as a propellant in metered-dose inhalant products, implying a low human toxicity risk from periodic brief exposures. There has been little published human or animal research evaluating possible neurobehavioral toxicity from longer HFC 134a exposures, as may be expected to occur in operational scenarios. In this study, male Wistar rats were exposed to various concentrations of HFC 134a or CFC 12 for up to 30 min while performing in either a rotarod/motorized running wheel apparatus or in an operant chamber The relative neurobehavioral toxicity of CFC 12 and its ozone-depleting substance replacement HFC 134a was assessed by comparing both gross motor system incapacitation and more subtle changes in ability to perform an operant discrimination task. It was shown that exposure to HFC 134a or CFC 12 concentrations from 40,000 to 470,000 ppm, for up to 30 min, induced neurobehavioral deficits in every subject, ranging from reduced operant efficiency to apparent anesthesia. For neurobehavioral endpoints examined in these experiments, HFC 134a inhalation was shown to induce deficits more rapidly, and at lower concentrations when compared to CFC 12 exposure. PMID:11405255

  12. Properties and Cycle Performance of Refrigerant Blends Operating Near and Above the Refrigerant Critical Point, Task 1: Refrigerant Properties

    SciTech Connect

    Mark O. McLinden; Arno Laesecke; Eric W. Lemmon; Joseph W. Magee; Richard A. Perkins

    2002-08-30

    The main goal of this project was to investigate and compare the performance of an R410A air conditioner to that of an R22 air conditioner, with specific interest in performance at high ambient temperatures at which the condenser of the R410A system may be operating above the refrigerant's critical point. Part 1 of this project consisted of measuring thermodynamic properties R125, R410A and R507A, measuring viscosity and thermal conductivity of R410A and R507A and comparing data to mixture models in NIST REFPROP database. For R125, isochoric (constant volume) heat capacity was measured over a temperature range of 305 to 397 K (32 to 124 C) at pressures up to 20 MPa. For R410A, isochoric heat capacity was measured along 8 isochores with a temperature range of 303 to 397 K (30 to 124 C) at pressures up to 18 MPa. Pressure-density-temperature was also measured along 14 isochores over a temperature range of 200 to 400 K (-73 to 127 C) at pressures up to 35 MPa and thermal conductivity along 6 isotherms over a temperature range of 301 to 404 K (28 to 131 C) with pressures to 38 MPa. For R507A, viscosity was measured along 5 isotherms over a temperature range of 301 to 421 K (28 to 148 C) at pressures up to 83 MPa and thermal conductivity along 6 isotherms over a temperature range of 301 to 404 K (28 to 131 C) with pressures to 38 MPa. Mixture models were developed to calculate the thermodynamic properties of HFC refrigerant mixtures containing R32, R125, R134a and/or R125. The form of the model is the same for all the blends considered, but blend-specific mixing functions are required for the blends R32/125 (R410 blends) and R32/134a (a constituent binary of R407 blends). The systems R125/134a, R125/143a, R134a/143a, and R134a/152a share a common, generalized mixing function. The new equation of state for R125 is believed to be the most accurate and comprehensive formulation of the properties for that fluid. Likewise, the mixture model developed in this work is the latest state-of-the-art for thermodynamic properties of HFC refrigerant blends. These models were incorporated into version 7 of NIST REFPROP database.

  13. The friction and wear behavior in controlled alternative refrigerant atmosphere

    NASA Astrophysics Data System (ADS)

    Mizuhara, K.; Akei, M.; Matsuzaki, T.

    1994-01-01

    Increased wear occurred in the actual refrigeration compressor when hydrofluorocarbon (HFC) refrigerants were substituted for chlorofluorocarbons (CFCs) to comply with the Montreal Protocol. A cause of this increased wear was believed to be the inferior extreme-pressure (EP) or antiwear capability of the alternative refrigerant HFC-134a as the environment gas, compared to that for CFC-12 refrigerant which is currently used. However, under some severe conditions, it was found that the alternative also showed some antiwear or EP effect by forming a fluoride layer on a sliding surface. The reason HFC-134a did not exhibit a lubricating effect, eventhough it had some capability to form a fluoride layer, was that the sliding condition required for HFCs to form a protective layer was more severe than that occurring in actual compressors. The mechanism of the atmospheric effect of refrigerant gases on friction and wear is also discussed.

  14. Estimation of the world-wide fleets of refrigerating and air-conditioning equipment in order to determine forecasts of refrigerant emissions

    Microsoft Academic Search

    Lionel Palandre; Assaad Zoughaib; Denis Clodic; L. Kuijpers

    A global analysis on CFC, HCFC and HFC emissions has been performed using data on annual equipment markets for appliances, air to air air-conditioning systems, chillers, mobile ari-conditioning systems, and refrigeration transportation. For commercial refrigeration and food processing, the number of refrigerating equipment is based on surveys of a limited number of countries, and on the use of ratios based

  15. Greenhouse gas emissions for refrigerant choices in room air conditioner units.

    PubMed

    Galka, Michael D; Lownsbury, James M; Blowers, Paul

    2012-12-01

    In this work, potential replacement refrigerants for window-mounted room air conditioners (RACs) in the U.S. have been evaluated using a greenhouse gas (GHG) emissions analysis. CO(2)-equivalent emissions for several hydrofluoroethers (HFEs) and other potential replacements were compared to the most widely used refrigerants today. Included in this comparison are pure refrigerants that make up a number of hydrofluorocarbon (HFC) mixtures, pure hydrocarbons, and historically used refrigerants such as propane and ammonia. GHG emissions from direct and indirect sources were considered in this thermodynamic analysis. Propylene, dimethyl ether, ammonia, R-152a, propane, and HFE-152a all performed effectively in a 1 ton window unit and produced slightly lower emissions than the currently used R-22 and R-134a. The results suggest that regulation of HFCs in this application would have some effect on reducing emissions since end-of-life emissions remain at 55% of total refrigerant charge despite EPA regulations that mandate 80% recovery. Even so, offsite emissions due to energy generation dominate over direct GHG emissions and all the refrigerants perform similarly in totals of indirect GHG emissions. PMID:23136858

  16. The large contribution of projected HFC emissions to future climate forcing

    PubMed Central

    Velders, Guus J. M.; Fahey, David W.; Daniel, John S.; McFarland, Mack; Andersen, Stephen O.

    2009-01-01

    The consumption and emissions of hydrofluorocarbons (HFCs) are projected to increase substantially in the coming decades in response to regulation of ozone depleting gases under the Montreal Protocol. The projected increases result primarily from sustained growth in demand for refrigeration, air-conditioning (AC) and insulating foam products in developing countries assuming no new regulation of HFC consumption or emissions. New HFC scenarios are presented based on current hydrochlorofluorocarbon (HCFC) consumption in leading applications, patterns of replacements of HCFCs by HFCs in developed countries, and gross domestic product (GDP) growth. Global HFC emissions significantly exceed previous estimates after 2025 with developing country emissions as much as 800% greater than in developed countries in 2050. Global HFC emissions in 2050 are equivalent to 9–19% (CO2-eq. basis) of projected global CO2 emissions in business-as-usual scenarios and contribute a radiative forcing equivalent to that from 6–13 years of CO2 emissions near 2050. This percentage increases to 28–45% compared with projected CO2 emissions in a 450-ppm CO2 stabilization scenario. In a hypothetical scenario based on a global cap followed by 4% annual reductions in consumption, HFC radiative forcing is shown to peak and begin to decline before 2050. PMID:19549868

  17. Evaluation of HFC-245ca for commercial use in low pressure chillers. Final report, Volume I

    SciTech Connect

    Keuper, E.F. [Trane Co., LaCrosse, WI (United States)] [Trane Co., LaCrosse, WI (United States)

    1996-03-01

    Federal regulations banned the production of CFC-11 on January 1, 1996. HCFC-123, the only commercial alternative, will be limited to service applications after January 1, 2020 and will be eliminated from production on January 1, 2030. HFC-245ca has been identified as a potential replacement for CFC-11 in retrofit applications and for HCFC-123 in new chillers, but the marginal flammability of HFC-245ca is a major obstacle to its commercial use as a refrigerant in the United States. This report assesses the commercial viability of HFC-245ca based on its experimental performance in a direct drive low pressure centrifugal chiller exclusive of its flammability characteristics. Three different impeller diameters were tested in the chiller, with all impellers having identical discharge blade angles. Experimental work included tests in a 200 ton 3 stage direct drive chiller with 3 impeller sets properly sized for each of three refrigerants, CFC-11, HCFC-123, and HFC-245ca. The commercial viability assessment focused on both retrofit and new product performance and cost.

  18. Design and simulation of a heat pump for simultaneous heating and cooling using HFC or CO2

    E-print Network

    Paris-Sud XI, Université de

    1 Design and simulation of a heat pump for simultaneous heating and cooling using HFC or CO2: +33 2 23 23 42 97 Fax: +33 2 23 23 40 51 ABSTRACT This article presents a Heat Pump for Simultaneous heat pump i in is isentropic mec mechanical nof without frosting o out r refrigerant S sublimation sc

  19. Reproductive and developmental toxicity of hydrofluorocarbons used as refrigerants.

    PubMed

    Ema, Makoto; Naya, Masato; Yoshida, Kikuo; Nagaosa, Ryuichi

    2010-04-01

    The present paper summarizes data on the reproductive and developmental toxicity of hydrofluorocarbons (HFCs), including pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), difluoromethane (HFC-32) and 1,1,1,3,3-pentafluoropropane (HFC-245fa), used as refrigerants, published in openly available scientific literature. No developmental toxicity of HFC-125 was found even at 50,000 ppm in rats or rabbits. Although HFC-134a exhibited no dominant lethal effect or reproductive toxicity in rats, it caused low body weight in pre- and postnatal offspring and slightly retarded skeletal ossification in fetuses at 50,000 ppm in rats. No maternal or developmental toxicity was noted after exposure to HFC-143a even at 40,000 ppm in rats or rabbits or HFC-152a even at 50,000 ppm in rats. HFC-32 is slightly maternally and developmentally toxic at 50,000 ppm in rats, but not in rabbits. HFC-245fa caused decreases in maternal body weight and food consumption at 10,000 and 50,000 ppm and fetal weight at 50 000ppm. No evidence of teratogenicity for these HFCs was noted in rats or rabbits. There is limited information about the reproductive toxicity of these HFCs. Animal studies remain necessary for risk assessments of chemicals because it is difficult to find alternative methods to determine the toxic effects of chemicals. It is required to reduce emissions of organic vapors containing HFCs to reduce the risk of exposure. PMID:19914373

  20. Formation and dissociation of HFC134a gas hydrate in nano-copper suspension

    Microsoft Academic Search

    Jinping Li; Deqing Liang; Kaihua Guo; Ruzhu Wang; Shuanshi Fan

    2006-01-01

    The major technical issue in gas hydrates energy storage systems is how to increase the refrigerants-water mass and heat transfer and how to realize a rapid formation of clathrate hydrate. Borrowing ideas from heat transfer enhancement of the fluid with the addition of nano-sized particles, the formation and dissociation of HFC134a (CH2FCF3) hydrate were studied in nano-copper suspensions of different

  1. Growth of climate change commitments from HFC banks and emissions

    NASA Astrophysics Data System (ADS)

    Velders, G. J. M.; Solomon, S.; Daniel, J. S.

    2013-12-01

    Chlorofluorocarbons (CFCs) are the primary cause of ozone depletion, and they also contribute to global climate change. With the global phaseout of CFCs and the coming phaseout of hydrochlorofluorocarbons (HCFCs), the substitute hydrofluorocarbons (HFCs) are increasingly used. While CFCs were originally used mainly in applications such as spray cans and were released within a year after production, concern about the ozone layer led to reductions in rapid-release applications, and the relative importance of slower-release applications grew. HFCs are now mainly used in refrigerators and air-conditioners (AC) and are released over years to a decade after production. Their containment in such equipment represents banks, which are building up as production grows. A key finding of our work is that the increases of HFC banks represent a substantial unseen commitment to further radiative forcing of climate change after production of the chemicals ceases. We show that earlier phaseouts of HFCs would provide greater benefits for climate protection than previously recognized, due to the avoided buildup of the banks. If, for example, HFC production were to be phased out in 2020 instead of 2050, not only would about 91-146 GtCO2eq of cumulative emission be avoided from 2020 to 2050, but an additional bank of about 39-64 GtCO2eq is also avoided in 2050. Choices of later phaseout dates lead to larger commitments to climate change unless growing banks of HFCs from millions of dispersed locations are collected and destroyed.

  2. Growth of climate change commitments from HFC banks and emissions

    NASA Astrophysics Data System (ADS)

    Velders, G. J. M.; Solomon, S.; Daniel, J. S.

    2014-05-01

    Chlorofluorocarbons (CFCs) are the primary cause of ozone depletion, and they also contribute to global climate change. With the global phaseout of CFCs and the coming phaseout of hydrochlorofluorocarbons (HCFCs), the substitute hydrofluorocarbons (HFCs) are increasingly used. While CFCs were originally used mainly in applications such as spray cans and were released within a year after production, concern about the ozone layer led to reductions in rapid-release applications, and the relative importance of slower-release applications grew. HFCs are now mainly used in refrigerators and air conditioners (AC) and are released over years to a decade after production. Their containment in such equipment represents banks, which are building up as production grows. A key finding of our work is that the increases of HFC banks represent a substantial unseen commitment to further radiative forcing of climate change also after production of the chemicals ceases. We show that earlier phaseouts of HFCs would provide greater benefits for climate protection than previously recognized, due to the avoided buildup of the banks. If, for example, HFC production were to be phased out in 2020 instead of 2050, not only could about 91-146 GtCO2-eq of cumulative emission be avoided from 2020 to 2050, but an additional bank of about 39-64 GtCO2-eq could also be avoided in 2050. Choices of later phaseout dates lead to larger commitments to climate change unless growing banks of HFCs from millions of dispersed locations are collected and destroyed.

  3. Study of the Vapor-Liquid Coexistence Curve and the Critical Curve for Nonazeotropic Refrigerant Mixture R152a + R114 System

    NASA Astrophysics Data System (ADS)

    Kabata, Yasuo; Higashi, Yukihiro; Uematsu, Masahiko; Watanabe, Koichi

    Measurements of the vapor-liquid coexistence curve in the critical region for the refrigerant mixture of R152a (CH3CHF2: 1, l-difluoroethane) +R 114 (CCIF2CCIF2 :1, 2-dichloro-1, 1, 2, 2-tetrafluoroethane) system were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Forty-eight saturated densities along the vapor-liquid coexistence curve between 204 and 861 kg·m-3 for five different compositions of 10, 20, 50, 80 and 90 wt% R 152a were obtained in the temperature range 370 to 409 K. The experimental errors of temperature, density, and mass fraction were estimated within ±10mK, ±0.5% and +0.05 %, respectively. On the basis of these measurements, the critical parameters of five different compositions for the R 152a +R 114 system were determined in consideration of the meniscus disappearance level as well as intensity of the critical opalescence. In accordance with the previous results of three other refrigerant mixtures, i.e., R 12 +R 22 system, R 22 +R 114 system and R 13B1 + R 114 system, the coexistence curve and critical curve on the temperature-density diagram for binary refrigerant mixtures were discussed. In addition, correlations of its composition dependence for this system were proposed.

  4. Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

    This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

  5. Enhancing the performance of evaporative spray cooling in air cycle refrigeration and air conditioning technology

    Microsoft Academic Search

    S. Hamlin; R. Hunt; S. A. Tassou

    1998-01-01

    The phase out of CFC refrigerants and the concern over their proposed replacements, HFC, has led to a reassessment of many natural refrigeration technologies including air cycle. It is recognised that to fulfil the full potential of air cycle technology, improvements in system energy consumption must be made. One area where it is believed that significant energy savings can be

  6. Needs of thermodynamic properties measurements and modeling in the frame of new regulations on refrigerants

    Microsoft Academic Search

    Christophe Coquelet; Dominique Richon

    2007-01-01

    In 1987, the Montreal Protocol prohibited the worldwide use and production of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons\\u000a (HCFCs) and hydro fluorocarbons (HFCs) were proposed as alternative refrigerants. Unfortunately, HFCs have non negligible\\u000a global warning potential and therefore new refrigerants must be proposed or old refrigerants must be used associated with\\u000a HFC. Accurate experimental thermodynamic data and predictive techniques are required for

  7. Potentially acceptable substitutes for the chlorofluorocarbons: properties and performance features of HFC-134a, HCFC-123, and HCFC-141b

    NASA Astrophysics Data System (ADS)

    Sukornick, B.

    1989-05-01

    Potentially acceptable substitutes are known for CFC-11 and CFC-12-the most important Chlorofluorocarbons. HFC-134a could replace CFC-12 in airconditioning and refrigeration and both HCFC-123 and HCFC-141b show promise as CFC-11 substitutes. The replacement molecules all have significantly reduced greenhouse and ozone depletion potentials compared to their fully halogenated counterparts. HCFC-123 is theoretically a less efficient blowing agent than CFC-11, but 141b is more efficient. Results from experimental foaming tests confirm these relationships and show that initial insulating values are slightly lower for 141b and 123 than 11. Both substitutes are nonflammable liquids. Based on its physical properties, HFC-134a is an excellent replacement candidate for CFC-12. In addition, it is more thermally stable than CFC-12. A new family of HFC-134a compatible lubricant oils will be required. The estimated coefficient of performance (COP) of 134a is 96 98% that of CFC-12. Subacute toxicity tests show HFC-134a to have a low order of toxicity. HCFC-123 reveals no serious side effects at a concentration of 0.1% in subchronic tests and the inhalation toxicity of 141b is lower than that of CFC-11 based on a 6-h exposure. Chronic tests on all the new candidates will have to be completed for large-scale commercial use. Allied-Signal is conducting process development at a highly accelerated pace, and we plan to begin commercialization of substitutes within 5 years.

  8. Overview of CFC replacement issues for household refrigeration

    SciTech Connect

    Vineyard, E.A. [Oak Ridge National Lab., TN (United States); Roke, L. [Fisher and Paykel, Auckland (New Zealand); Hallett, F. [Frigidaire, Washington, DC (United States)

    1991-12-31

    In 1974, the famous ozone depletion theory of Rowland and Molina claimed that chlorofluorocarbons (CFCs) diffuse into the stratosphere where they are broken down by photolysis to release chlorine atoms that catalytically destroy ozone. Although the understanding of the science is still imperfect, there is little doubt that CFCs play a major role in the Antarctic ozone hole phenomenon and the decline in ozone observed in the rest of the world. Another issue that has become increasingly important is the potential of CFCs to change the earth`s temperature and to modify the climate. While the main impact in global warming is made by increased concentrations of carbon dioxide, CFCs and other trace gases also contribute to this effect. In an effort to respond to the global environmental threat, a CFC protocol was adopted during a diplomatic conference in Montreal. This document, known as the Montreal Protocol, was ratified in 1988 and put into effect on January 1, 1989. In accordance with Article 6 of the Montreal Protocol, the countries that signed the agreement shall periodically assess the control measures provided for in the Protocol. As part of that assessment process, household refrigeration was investigated to determine the status of CFC-12 replacements. The conclusion was that much progress has been made towards finding a suitable replacement. Compressors designed for HFC-134a have efficiencies comparable to those for CFC-12 and acceptable reliability tests have been obtained with ester lubricants. In addition, other replacements such as R-152a and refrigerant mixtures exist, but will require more study. Cycle options, such as the Stirling cycle, may be viable, but are further out in the future. The impact of new refrigerants is expected to result in elimination of CFC-12 consumption in developed countries by 1997 and in developing countries by 2005.

  9. Overview of CFC replacement issues for household refrigeration

    SciTech Connect

    Vineyard, E.A. (Oak Ridge National Lab., TN (United States)); Roke, L. (Fisher and Paykel, Auckland (New Zealand)); Hallett, F. (Frigidaire, Washington, DC (United States))

    1991-01-01

    In 1974, the famous ozone depletion theory of Rowland and Molina claimed that chlorofluorocarbons (CFCs) diffuse into the stratosphere where they are broken down by photolysis to release chlorine atoms that catalytically destroy ozone. Although the understanding of the science is still imperfect, there is little doubt that CFCs play a major role in the Antarctic ozone hole phenomenon and the decline in ozone observed in the rest of the world. Another issue that has become increasingly important is the potential of CFCs to change the earth's temperature and to modify the climate. While the main impact in global warming is made by increased concentrations of carbon dioxide, CFCs and other trace gases also contribute to this effect. In an effort to respond to the global environmental threat, a CFC protocol was adopted during a diplomatic conference in Montreal. This document, known as the Montreal Protocol, was ratified in 1988 and put into effect on January 1, 1989. In accordance with Article 6 of the Montreal Protocol, the countries that signed the agreement shall periodically assess the control measures provided for in the Protocol. As part of that assessment process, household refrigeration was investigated to determine the status of CFC-12 replacements. The conclusion was that much progress has been made towards finding a suitable replacement. Compressors designed for HFC-134a have efficiencies comparable to those for CFC-12 and acceptable reliability tests have been obtained with ester lubricants. In addition, other replacements such as R-152a and refrigerant mixtures exist, but will require more study. Cycle options, such as the Stirling cycle, may be viable, but are further out in the future. The impact of new refrigerants is expected to result in elimination of CFC-12 consumption in developed countries by 1997 and in developing countries by 2005.

  10. Photographic Study of Bubble Behaviors for Saturated Pool Boiling of Binary Refrigerant Mixture R141B-R113

    Microsoft Academic Search

    Y. H. Diao; Y. H. Zhao; Q. L. Wang

    2006-01-01

    A visual study was performed on the boiling behavior for binary mixture R141b-R113 by using a high-speed digital camera to record the bubble behaviors during boiling process. The bubble departure diameter, departure time, and nucleation density for boiling heater surface as functions of composition at different heat fluxes for binary mixtures were presented. Strong effects of composition on these three

  11. Aging of polyurethane foam insulation in simulated refrigerator panels -- Initial results with third-generation blowing agents

    Microsoft Academic Search

    K. E. Wilkes; W. A. Gabbard; F. J. Weaver

    1998-01-01

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements -- HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and -10 F. Thermal conductivity measurements were

  12. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels--One-Year Results with Third-Generation Blowing Agents

    Microsoft Academic Search

    W. A. Gabbard; F. J. Weaver; K. E. Wilkes

    1999-01-01

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements--HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and -10 F. Thermal conductivity measurements were made on

  13. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels—Two-Year Results with Third-Generation Blowing Agents

    Microsoft Academic Search

    Kenneth E. Wilkes; W. Alex Gabbard; Fred J. Weaver; J. Richard Booth

    2001-01-01

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements—HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90°F, 40°F, and-10°F. Thermal conductivity measurements were made on two types of specimens:

  14. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels–Three-Year Results with Third-Generation Blowing Agents

    Microsoft Academic Search

    Kenneth E. Wilkes; David W. Yarbrough; W. A. Gabbard; Gary E. Nelson; J. Richard Booth

    2002-01-01

    Laboratory data are presented on the effect of constant temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements—HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and-10 F. Thermal conductivity measurements were made on

  15. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels--Three-Year Results with Third-Generation Blowing Agents

    Microsoft Academic Search

    Wilkes

    2001-01-01

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements--HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and -10 F. Thermal conductivity measurements were made on

  16. Experimental study on HFC125 critical heat pump

    Microsoft Academic Search

    Xiangjiang Zhou; Zhiwei Lian; Zhihua Li; Ye Yao

    2007-01-01

    A critical cycle heat pump with HFC125 was studied experimentally. The experimental result indicates that the heat pump with HFC125 can use the general components of the conventional heat pump well. Hot water with wide-range temperature can be conveniently got by the critical heat pump system through water flow control. The COPh of the critical cycle drops a little when

  17. Alternative refrigerants and refrigeration cycles for domestic refrigerators

    SciTech Connect

    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) 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.

  18. Simulation of refrigerant phase equilibria

    Microsoft Academic Search

    Arthur S. Gow; Xinzhou Guo; Delong Liu; Angelo Lucia

    1997-01-01

    Vapor-liquid equilibria for refrigerant mixtures modeled by an equation of state are studied. Phase behavior calculated by the Soave-Redlich-Kwong (SRK) equation with a single adjustable binary interaction parameter is compared with experimental data for binary refrigerant mixtures, two with a supercritical component and one that exhibits azeotropic behavior. It is shown that the SRK equation gives an adequate description of

  19. Phase Diagram Calculation of Gas Mixtures for Refrigeration; Reflection & Transmission Coefficients and the Effective Mass: Superconducting Proximity I-V Measurements.

    NASA Astrophysics Data System (ADS)

    Friedmann, Gideon

    The efficiency of Joule-Thomson refrigerators greatly improves with the addition of hydrocarbons to nitrogen as coolant, and is highly dependent on the mixture composition. To optimize it, we calculated the mixture phase diagram using the Peng-Robinson equation of state. A program was developed to solve numerically a set of coupled non-linear equations for the equilibrium of the vapor and liquid phases of each mixture component. The program is highly efficient, quite stable, and reliable. Gases can be easily added to the program's database. We found that the cooling efficiency of the mixtures has a sharp ridge in composition space, and explain this. To better understand tunneling spectra of the high T_{rm c} cuprate superconductors, we analyzed the one-dimensional behavior of the wavefunction of a free particle striking a crystal interface. We describe the free particle using a wavepacket of plane waves, and the crystal using the Kronig-Penney model. We find that when the wavepacket is spread over many unit cells, it behaves like a free particle wavepacket striking a small potential step. The reflection and transmission coefficients are derived and one finds that they do not contain the particle's effective mass. We determine that the boundary conditions used in a standard effective mass approach must be modified to make it work. We conclude that one should not use the effective mass approximation in treating high T_{rm c} superconductor interfaces. We measured the dynamic resistance of a superconducting -normal metal-normal metal (SNN') geometry and observed that N', a superconductor at low enough temperatures, displays superconducting properties above its critical temperature. They disappear well below the critical temperature of S. We present a simple model of the proximity effect, which is self-consistent at any temperature and good for arbitrary thicknesses of N. The model shows how the superconducting gap decays with the distance from S. We observe that the proximity effect is long-ranged when the temperature is not much above the critical temperature of N'. We also present a calculation of the Andreev reflection coefficient in an SNS geometry, that may help to explain sharp resistive peaks previously observed by Holcomb.

  20. Optimum Refrigerant Selection for Low Temperature Engineering

    Microsoft Academic Search

    V. Mazur

    \\u000a The selection of refrigerants or refrigerant mixtures with desirable combination of such properties as contribution to greenhouse\\u000a effect, flammability, toxicity, thermodynamic behavior, performance specifications, and the others is one of the most important\\u000a stages in simulation and design of refrigeration processes. Refrigerant selection problem has been tackled using achievements\\u000a of molecular theory, engineering experience and experimental studies [1], [2], [3],

  1. Second-law-based thermodynamic analysis of two-stage and mechanical-subcooling refrigeration cycles

    Microsoft Academic Search

    S. M Zubair; M Yaqub; S. H Khan

    1996-01-01

    Thermodynamic analysis of HFC-134a vapor-compression refrigeration cycles is investigated by both the first and second laws of thermodynamics. Second-law analysis is carried out for both two-stage and mechanical-subcooling refrigeration cycles. The analysis is performed on each of the system components to determine their individual contribution to the overall system irreversible losses. It is found that most of the losses are

  2. Pool boiling of enhanced heat transfer surfaces in refrigerant-oil mixtures and aqueous calcium sulfate solutions

    SciTech Connect

    Curcio, L.A.; Somerscales, E.F.

    1994-08-01

    Pool boiling data of structured surfaces in R113/3GS oil mixtures show a general decrease in heat transfer with oil concentration, degradation in performance of all surfaces at 10% oil, no change in enhancement of the structured surfaces over plain surface, and restoration of performance of the enhanced surfaces upon cleaning in denatured alcohol. Fouling data of structured surfaces in pool boiling of sat. aq. CaSO{sub 4} solution show that effects of fouling (wall superheat changes, deposit weight) are more pronounced at 80 kW/m{sup 2} than at 10 kW/m{sup 2} heat flux; precipitation fouling show an effect within the first 2 h exposure. High flux surfaces have lower deposition weight than other surfaces; thus the deposition rate may depend strongly on wall superheat. The numerous nucleation sites of the enhanced surfaces provide more turbulent motion near the boiling surface than for the plain surface; thus the removal rate should be greater for an enhanced surface, although no removal of a deposit was ever observed.

  3. Global emissions of HFC-23 estimated to year 2015

    NASA Astrophysics Data System (ADS)

    McCulloch, A.; Lindley, A. A.

    HFC-23 (trifluoromethane, fluoroform, CHF 3) is a powerful greenhouse gas that is formed at the reactor stage of the manufacture of HCFC-22 (chlorodifluoromethane, CHClF 2). The amount formed depends on the conditions used in the manufacturing process and, for individual plants, lies between 1% and 4% of the production of HCFC-22. While it is possible to reduce the formation of HFC-23 by optimising process conditions, it is not possible to eliminate its production. This requires destruction, generally by thermal oxidation. Under the Kyoto Protocol, developed countries have obligations to reduce greenhouse gas emissions and, in the developing world, there are projects under the Clean Development Mechanism for the incineration of HFC-23 waste streams. These should lead to a reduction in average global emission factors relative to production of HCFC-22. We present estimates of global production of HCFC-22 up to the year 2015 and also the calculated range of emissions of HFC-23 that may be consequences of this. In terms of the effect on climate change, the atmospheric burden of HFC-23 accumulated from emissions is calculated to contribute between 0.1% and 0.2% of the radiative forcing of climate in 2015. Annual emissions of HFC-23 would be equivalent to between 284 and 28 million tonnes of CO 2 in that year, when total anthropogenic greenhouse gas emissions are predicted to lie between 46,000 million and 59,000 million tonnes of CO 2 equivalent.

  4. 1. INTRODUCTION As a result of the phas e-out of CFC and HCFC refrigerants

    E-print Network

    Kandlikar, Satish

    , refrigeration and air-conditioning systems, the binary and ternary refrigerant mixtures have received attention mixtures, which are currently being considered as potential replacements in refrigeration and air-conditioning1 1. INTRODUCTION As a result of the phas e-out of CFC and HCFC refrigerants in heat pump

  5. A recuperative superfluid stirling refrigerator

    SciTech Connect

    Brisson, J.G.; Swift, G.W.

    1993-07-01

    A superfluid Stirling refrigerator has been built with a counterflow heat exchanger serving as a recuperative regenerator. It has achieved temperatures of 296 mK with a 4% {sup 3}He-{sup 4}He mixture. Cooling power versus temperature and speed is presented for a 6.6% mixture.

  6. A recuperative superfluid stirling refrigerator

    SciTech Connect

    Brisson, J.G.; Swift, G.W. [Los Alamos National Lab., NM (United States)

    1994-12-31

    A superfluid Stirling refrigerator has been built with a counterflow heat exchanger serving as a recuperative regenerator. It has achieved temperatures of 296 mK with a 4% {sup 3}He-{sup 4}He mixture. Cooling power versus temperature and speed is presented for a 6.6% mixture.

  7. 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.

  8. Thermotile Refrigerators

    NASA Technical Reports Server (NTRS)

    Park, Brian V.

    1994-01-01

    Thermoelectric tiles provide cooling exactly where needed. Thermotile is modular thermoelectric cooling unit that incorporates sensor and electronic circuitry in addition to thermoelectric device. Refrigerator/freezer is lined with thermotiles clipped into supporting lattices. Small fans used to circulate air in refrigerator and freezer compartments. Elimination of conventional mechanical refrigeration machinery reduces number of moving parts and completely eliminates noise and vibration. Data capabilities of thermotile refrigeration system used for diagnosis of defects or monitoring local temperatures. Thermotiles produced by automated manufacturing techniques. Custom shapes molded as needed.

  9. The development of a proff of principle superfluid Joule-Thomson refrigerator for cooling below 1 Kelvin

    E-print Network

    Miller, Franklin K., 1970-

    2005-01-01

    A new type of sub-Kelvin refrigerator, the superfluid Joule-Thomson refrigerator, has been developed and its performance has been experimentally verified. This refrigerator uses a liquid superfluid mixture of He and 4He ...

  10. Reconciling reported and unreported HFC emissions with atmospheric observations.

    PubMed

    Lunt, Mark F; Rigby, Matthew; Ganesan, Anita L; Manning, Alistair J; Prinn, Ronald G; O'Doherty, Simon; Mühle, Jens; Harth, Christina M; Salameh, Peter K; Arnold, Tim; Weiss, Ray F; Saito, Takuya; Yokouchi, Yoko; Krummel, Paul B; Steele, L Paul; Fraser, Paul J; Li, Shanlan; Park, Sunyoung; Reimann, Stefan; Vollmer, Martin K; Lunder, Chris; Hermansen, Ove; Schmidbauer, Norbert; Maione, Michela; Arduini, Jgor; Young, Dickon; Simmonds, Peter G

    2015-05-12

    We infer global and regional emissions of five of the most abundant hydrofluorocarbons (HFCs) using atmospheric measurements from the Advanced Global Atmospheric Gases Experiment and the National Institute for Environmental Studies, Japan, networks. We find that the total CO2-equivalent emissions of the five HFCs from countries that are required to provide detailed, annual reports to the United Nations Framework Convention on Climate Change (UNFCCC) increased from 198 (175-221) Tg-CO2-eq?y(-1) in 2007 to 275 (246-304) Tg-CO2-eq?y(-1) in 2012. These global warming potential-weighted aggregated emissions agree well with those reported to the UNFCCC throughout this period and indicate that the gap between reported emissions and global HFC emissions derived from atmospheric trends is almost entirely due to emissions from nonreporting countries. However, our measurement-based estimates of individual HFC species suggest that emissions, from reporting countries, of the most abundant HFC, HFC-134a, were only 79% (63-95%) of the UNFCCC inventory total, while other HFC emissions were significantly greater than the reported values. These results suggest that there are inaccuracies in the reporting methods for individual HFCs, which appear to cancel when aggregated together. PMID:25918401

  11. Laboratory testing of a heat pump system with water-to-water, counterflow heat exchangers using various compositions of an R13B1/R152a nonazeotropic refrigerant mixture

    SciTech Connect

    Vineyard, E.A.

    1987-01-01

    Testing was performed with a nonazeotropic refrigerant mixture of R13B1/R152a to determine its ability to achieve capacity, relative to R/22, at low ambient temperatures. The selection of such a mixture could improve the efficiency of a heat pump by decreasing the cycling losses, which account for approximately 7-12% of the annual energy use, along with decreasing the amount of resistance heat required at low ambient temperatures. Results for the mixture show a potential capacity modulation from 12431 Btu/hr (3643 W) at 17 F (-8.3 deg C) to 8550 Btu/hr (2506 W) at 47 F (8.3 deg C) in heating and from 7451 Btu/h (2184 W) at 82 F (27.8 deg C) to 9188 Btu/h (2693 W) at 95 F (35 deg C) in cooling. An analysis of the coefficients of performance for the mixture and its pure components is presented along with a comparison against results obtained with R/22. The comparison is based on maintaining equivalent inlet and exit water temperatures in the evaporator and condenser for both R/22 and the mixtures. 4 refs., 8 figs., 4 tabs.

  12. Inventory and mitigation opportunities for HFC-134a emissions from nonprofessional automotive service

    NASA Astrophysics Data System (ADS)

    Zhan, Tao; Potts, Winston; Collins, John F.; Austin, Jeff

    2014-12-01

    Many vehicle owners in the United States recharge their vehicles' air conditioning systems with small containers of hydrofluorocarbon-134a (HFC-134a, CH2FCF3), at a frequency estimated to be once every year on average. Such nonprofessional service produces immediate emissions of this potent greenhouse gas during service and from the residual heel in partially used containers. The nonprofessional operations are also associated with increased delayed refrigerant emissions that occur because owners are less likely to repair leaks than professional technicians. In California, an estimated 1.3 million nonprofessional service operations performed each year generate 0.27 ± 0.07 million metric ton CO2 equivalent (MMTCO2e) of immediate emissions and 0.54 ± 0.08 MMTCO2e of delayed emissions, using a Global Warming Potential of 1300 for HFC-134a. The immediate emissions can be largely mitigated by a regulation that requires self-sealing valves and improved labeling instructions on the containers, a deposit-return-recycling program for the containers, and a consumer education program. If 95% of the used containers were to be returned by consumers for recycling of the container heel, the annual immediate emissions would be reduced by 0.26 ± 0.07 MMTCO2e. In the United States, an estimated 24 million nonprofessional service operations are performed each year, generating 5.1 ± 1.4 MMTCO2e of immediate emissions and 10.4 ± 1.5 MMTCO2e of delayed emissions. Mitigation measures equivalent to the California regulation would reduce nationwide immediate emissions by 4.9 ± 1.4 MMTCO2e, if 95% of the used cans were returned for recycling. These business-as-usual emissions and mitigation potentials are projected to stay approximately constant until around 2022, and remain at significant levels into the 2030s.

  13. Thermodynamic design principle of mixed-gases Kleemenko refrigeration cycles

    Microsoft Academic Search

    M. Q. Gong; E. C. Luo; J. F. Wu; Y. Zhou

    2002-01-01

    Mixed-gases throttling refrigeration cycles are recuperative cycles. The refrigeration system has at least one heat exchanger and from zero to three or more phase separators. Detailed discussions are made in this paper on the thermodynamic performance of several cycles, including extensive simulations and optimizations of mixtures, operating parameters of pressures, and flow configurations. The results show that the mixed refrigerant

  14. Infrared absorption cross-sections and integrated absorption intensities of HFC-134 and HFC-143a vapour.

    NASA Astrophysics Data System (ADS)

    Smith, K.; Newnham, D.; Page, M.; Ballard, J.; Duxbury, G.

    1998-05-01

    Infrared absorption cross-sections and integrated absorption intensities of HFC-134 (1,1,2,2-tetrafluoroethane) and HFC-143a (1,1,1-trifluoroethane) vapour have been determined from laboratory measurements at six temperatures (203, 213, 233, 253, 273 and 297 K) for the region 560-1900 cm-1 (5.3-17.9 ?m) at 0.03 cm-1 instrument resolution, by Fourier transform infrared spectroscopy. In addition, air-broadened spectra have been recorded at 297 K and pressures of 5, 20 and 100 kPa air. Inter-comparisons between this work and previous studies have been made where possible.

  15. Aging of polyurethane foam insulation in simulated refrigerator walls

    SciTech Connect

    Wilkes, K.E.; Yarbrough, D.W.; Weaver, F.J.

    1997-10-01

    Laboratory data are presented on the thermal conductivity of polyurethane foam insulation in composite test panels that simulate refrigerator walls. The test panels consisted of a steel skin, an ABS plastic liner, and a polyurethane foam core. Foam cores were produced with three different blowing agents (CFC-11, HCFC-141b, and a HCFC-142/22 blend). Periodic thermal measurements have been made on these panels over a three and one half year period in an effort to detect aging processes. Data obtained on foam encased in the panels were compared with measurements on thin foam slices that were removed from similar panels. The data show that the encapsulation of the foam in the solid boundary materials greatly reduces the aging rate. The plan is presented for a follow-on project that is being conducted on the aging of foams blown with HCFC-141b, HFC-134a, HFC-245fa, and cyclopentane.

  16. A study on the cycle characteristics of an auto-cascade refrigeration system

    Microsoft Academic Search

    Kai Du; Shaoqian Zhang; Weirong Xu; Xiaofeng Niu

    2009-01-01

    This study presents experimental results on the cycle characteristics of an auto-cascade refrigeration system. The auto-cascade refrigeration (ACR) system is driven by a single compressor, using zeotropic mixture as refrigerant, which achieves cascade between high and low boiling point components by an evaporative condenser for the purpose of obtaining a lower evaporation temperature comparing with single refrigerant system. The coefficient

  17. Effect of dissolved lubricating oils on the viscosity of alternative refrigerants

    Microsoft Academic Search

    Y. N. Chang; A. Nagashima

    1993-01-01

    The operation of refrigeration systems involves the circulation of a working fluid which is actually a mixture of refrigerant and lubricant oil. Since the viscosity of oil and that of refrigerants normally differ by up to a factor of 4, the effect of dissolved oil is very large. In order to use new alternative refrigerants, accurate information on thermophysical properties

  18. Thermoacoustic refrigeration

    SciTech Connect

    Garrett, S.L.; Hofler, T.J. (Naval Postgraduate School, Monterey, CA (United States))

    1992-12-01

    Shortly after their introduction, chlorofluorocarbons (CFCs) used as working fluids in a vapor compression (Rankine) refrigeration cycle became dominant in almost all small and medium-scale food refrigerator/freezer and building/residential air-conditioning applications. That situation is about to change dramatically and, at this moment, unpredictably. Two recent events are responsible for the new era in refrigeration that will dawn before the beginning of the 21st Century. The most significant of these is the international ban on the production of CFCs which were found to be destroying the Earth's protective ozone layer. The second event was the discovery of high temperature superconductors and the development of high speed and high density electronic circuits that require active cooling. It is the purpose of this article to introduce an entirely new approach to refrigeration that was first discovered in the early 1980s. This new approach-thermoacoustic refrigeration-uses high intensity sound waves to pump heat, with inert gases as the working fluid.

  19. 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.

  20. 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.

  1. Experiment and simulation on the performance of an autocascade refrigeration system using carbon dioxide as a refrigerant

    Microsoft Academic Search

    S. G Kim; M. S Kim

    2002-01-01

    The main purpose of this study is to investigate the performance of an autocascade refrigeration system using zeotropic refrigerant mixtures of R744\\/134a and R744\\/290. One of the advantages of this system is the possibility of keeping the highest pressure of the system within a limit by selecting the composition of a refrigerant mixture as compared to that in the vapor

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

    SciTech Connect

    Beshr, Mohamed [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Radermacher, Reinhard [University of Maryland, College Park

    2014-01-01

    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 LCCP 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.

  3. Choked flow mechanism of HFC-134a flowing through short-tube orifices

    SciTech Connect

    Nilpueng, Kitti; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok (Thailand)

    2011-02-15

    This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%. (author) transfer coefficient was also proposed. (author)

  4. Study on two stage activated carbon/HFC-134a based adsorption chiller

    NASA Astrophysics Data System (ADS)

    >K Habib, M. Amin B. A.; Sulaiman, Shaharin Anwar B.

    2013-06-01

    In this paper, a theoretical analysis on the performance of a thermally driven two-stage four-bed adsorption chiller utilizing low-grade waste heat of temperatures between 50°C and 70°C in combination with a heat sink (cooling water) of 30°C for air-conditioning applications has been described. Activated carbon (AC) of type Maxsorb III/HFC-134a pair has been examined as an adsorbent/refrigerant pair. FORTRAN simulation program is developed to analyze the influence of operating conditions (hot and cooling water temperatures and adsorption/desorption cycle times) on the cycle performance in terms of cooling capacity and COP. The main advantage of this two-stage chiller is that it can be operational with smaller regenerating temperature lifts than other heat-driven single-stage chillers. Simulation results shows that the two-stage chiller can be operated effectively with heat sources of 50°C and 70°C in combination with a coolant at 30°C.

  5. Thermoacoustic Refrigerator’s Stack Optimization

    Microsoft Academic Search

    Mawahib Hassan El-Fawal; Normah Mohd-Ghazali; Mohd. Shafik Yaacob; Amer Nordin Darus

    2010-01-01

    The standing wave thermoacoustic refrigerator, which uses sound generation to transfer heat, was developed rapidly during the past four decades. It was regarded as a new, promising and environmentally benign alternative to conventional compression vapor refrigerators, although it was not competitive regarding the coefficient of performance (COP) yet. Thus the aim of this paper is to enhance thermoacoustic refrigerator’s stack

  6. A Analysis of Magnetic Refrigeration and Refrigerants

    Microsoft Academic Search

    Michael Elra Wood

    1988-01-01

    A method for analyzing and optimizing magnetic refrigeration cycles is presented in general terms. This method involves the concept of refrigerant capacity or total work done by the refrigerant. A simple mean field theory is used to gain insight into the performance of different types of magnetic ordering (paramagnetic, ferromagnetic and antiferromagnetic) in reversible refrigeration cycles employing regenerators to heat

  7. Reduced-temperature processing and consolidation of ultra-refractory Ta4HfC5

    SciTech Connect

    Gaballa, Osama [Ames Laboratory; Cook, B. A. [TRI International; Russell, A. M. [Ames Laboratory

    2013-04-26

    TaC, HfC, and WC powders were subjected to high-energy milling and hot pressing to produce Ta4HfC5, a composite of Ta(4)HfC5 + 30 vol.% WC, and a composite of Ta4HfC5 + 50 vol.% WC. Sub-micron powders were examined after four different milling intervals prior to hot pressing. XRD was used to verify proper phase formation. SEM, relative density, and hardness measurements were used to examine the resulting phases. Hot pressed compacts of Ta4HfC5 showed densification as high as 98.6% along with Vickers hardness values of 21.4 GPa. Similarly, Ta4HfC5 + 30 vol.% WC exhibited 99% densification with a Vickers hardness of 22.5 GPa. These levels of densification were achieved at 1500 degrees C, which is lower than any previously reported sintering temperature for Ta4HfC5. Microhardness values measured in this study were higher than those previously reported for Ta4HfC5. The WC additions to Ta4HfC5 were found to improve densification and increase microhardness. (C) 2013 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Measurements with a recuperative superfluid Stirling refrigerator

    SciTech Connect

    Watanabe, A.; Swift, G.W.; Brisson, J.G.

    1995-08-01

    A superfluid Stirling refrigerator cooled to 168 mK using a 4.9% {sup 3}He- {sup 4}He mixture and exhausting its waste heat at 383 mK. Cooling power versus temperature and speed is presented for 4.9%, 17%, and 36% mixtures. At the highest concentration, a dissipation mechanism of unknown origin is observed.

  10. Measurements with a recuperative superfluid stirling refrigerator

    SciTech Connect

    Watanabe, A.; Swift, G.W.; Brisson, J.G. [Los Alamos National Lab., NM (United States)

    1996-12-31

    A superfluid Stirling refrigerator cooled to 168 mK using a 4.9 % {sup 3}He-{sup 4}He mixture and exhausting its waste heat at 383 mK. Cooling power versus temperature and speed is presented for 4.9%, 17%, and 36% mixtures. At the highest concentration, a dissipation mechanism of unknown origin is observed.

  11. Performance of alternative refrigerants for residential air-conditioning applications

    Microsoft Academic Search

    Ki-Jung Park; Taebeom Seo; Dongsoo Jung

    2007-01-01

    In this study, performances of two pure hydrocarbons and seven mixtures composed of propylene, propane, HFC152a, and dimethylether were measured to substitute for HCFC22 in residential air-conditioners and heat pumps. Thermodynamic cycle analysis was carried out to determine the optimum compositions before testing and actual tests were performed in a breadboard-type laboratory heat pump\\/air-conditioner at the evaporation and condensation temperatures

  12. LABORATORY INVESTIGATIONS OF INTERACTIONS OF IRRADIATED O-XYLENE/NOX/SO2/AIR MIXTURES WITH AQUEOUS MEDIA CONTAINING SODIUM FLUORIDE, SODIUM TRIFLUOROACETATE, AMMONIUM NITRATE AND HYDROGEN PEROXIDE

    EPA Science Inventory

    Laboratory experiments were conducted to investigate interactions between complex air mixtures and aqueous films containing hydrolysis products of hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) oxidation products. he experiments consisted of exposing aqueous films con...

  13. Fluorescent refrigeration

    DOEpatents

    Epstein, R.I.; Edwards, B.C.; Buchwald, M.I.; Gosnell, T.R.

    1995-09-05

    Fluorescent refrigeration is based on selective radiative pumping, using substantially monochromatic radiation, of quantum excitations which are then endothermically redistributed to higher energies. Ultimately, the populated energy levels radiatively deexcite emitting, on the average, more radiant energy than was initially absorbed. The material utilized to accomplish the cooling must have dimensions such that the exciting radiation is strongly absorbed, but the fluorescence may exit the material through a significantly smaller optical pathlength. Optical fibers and mirrored glasses and crystals provide this requirement. 6 figs.

  14. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels--One-Year Results with Third-Generation Blowing Agents

    SciTech Connect

    Gabbard, W.A.; Weaver, F.J.; Wilkes, K.E.

    1999-09-27

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements--HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and {minus}10 F. Thermal conductivity measurements were made on two types of specimens: full-thickness simulated refrigerator panels containing foam enclosed between solid plastic sheets, and thin slices of core foam cut from similar panels. Results are presented for the first year of a multi-year study for the full-thickness panels and for about 1-1/2 years of aging for the core-foam specimens.

  15. Aging of polyurethane foam insulation in simulated refrigerator panels -- Initial results with third-generation blowing agents

    SciTech Connect

    Wilkes, K.E.; Gabbard, W.A.; Weaver, F.J.

    1998-11-01

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements -- HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and {minus}10 F. Thermal conductivity measurements were made on two types of specimens: full-thickness simulated refrigerator panels containing foam enclosed between solid plastic sheets, and thin slices of core foam cut from similar panels. Results are presented for about 250 days of aging for the core-foam specimens and for the first six months of aging for the full-thickness panels.

  16. Theoretical investigations on simultaneous operation of vapour compression refrigeration cycle and Stirling cycle in miniature Stirling cooler with two-component two-phase mixture

    Microsoft Academic Search

    S. L Bapat

    2000-01-01

    The cyclic analysis of Stirling cycle working with a single gaseous fluid is modified to suit two-component two-phase mixtures. When the results were examined carefully, these showed that a substantial increase in cooling effect is obtained. In order to understand how the two-component two-phase working fluid functions in the Stirling cooler, some other processes, generally not coming into picture with

  17. Liquid-air partition coefficients of 1,1-difluoroethane (HFC152a), 1,1,1-trifluoroethane (HFC143a), 1,1,1,2-tetrafluoroethane (HFC134a), 1,1,1,2,2-pentafluoroethane (HFC125) and 1,1,1,3,3-pentafluoropropane (HFC245fa).

    PubMed

    Ernstgård, Lena; Lind, Birger; Andersen, Melvin E; Johanson, Gunnar

    2010-01-01

    Blood-air and tissue-blood coefficients (lambda) are essential to characterize the uptake and disposition of volatile substances, e.g. by physiologically based pharmacokinetic (PBPK) modelling. Highly volatile chemicals, including many hydrofluorocarbons (HFC) have low solubility in liquid media. These characteristics pose challenges for determining lambda values. A modified head-space vial equilibrium method was used to determine lambda values for five widely used HFCs. The method is based on automated head-space gas chromatography and injection of equal amount of chemical in two head-space vials with identical air phase volumes but different volumes of the liquid phase. The liquids used were water (physiological saline), fresh human blood, and olive oil. The average lambda values (n = 8) were as follows: 1,1-difluoroethane (HFC152a) - 1.08 (blood-air), 1.11 (water-air) and 5.6 (oil-air); 1,1,1-trifluoroethane (HFC143a) - 0.15, 0.15 and 1.90; 1,1,1,2-tetrafluoroethane (HFC134a) - 0.36, 0.35 and 3.5; 1,1,1,2,2-pentafluoroethane (HFC125) - 0.083, 0.074 and 1.71; and 1,1,1,3,3-pentafluoropropane (HFC245fa) - 0.62, 0.58 and 12.1. The lambda values appeared to be concentration-independent in the investigated range (2-200 ppm). In spite of the low lambda values, the method errors were modest, with coefficients of variation of 9, 11 and 10% for water, blood and oil, respectively. PMID:19701883

  18. ARTI refrigerant database

    SciTech Connect

    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.

  19. ARTI refrigerant database

    SciTech Connect

    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.

  20. Influence of Oil on Refrigerant Evaporator Performance

    NASA Astrophysics Data System (ADS)

    Kim, Jong-Soo; Nagata, Karsuya; Katsuta, Masafumi; Tomosugi, Hiroyuki; Kikuchi, Kouichiro; Horichi, Toshiaki

    In vapor compression refrigeration system using oil-lubricated compressors, some amount of oil is always circulated through the system. Oil circulation can have a significant influence on the evaporator performance of automotive air conditioner which is especially required to cool quickly the car interior after a period standing in the sun. An experimental investigation was carried out an electrically heated horizontal tube to measure local heat transfer coefficients for various flow rates and heat fluxes during forced convection boiling of pure refrigerant R12 and refrigerant-oil mixtures (0-11% oil concentration by weight) and the results were compared with oil free performance. Local heat transfer coefficients increased at the region of low vapor quality by the addition of oil. On the other hand, because the oil-rich liquid film was formed on the heat transfer surface, heat transfer coefficients gradually decreased as the vapor quality became higher. Average heat transfer coefficient reached a maximum at about 4% oil concentration and this trend agreed well with the results of Green and Furse. Previous correlations, using the properties of the refrigerant-oil mixture, could not predict satisfactorily the local heat transfer coefficients data. New correlation modified by oil concentration factor was developed for predicting the corresponding heat transfer coefficient for refrigerant-oil mixture convection boiling. The maximum percent deviation between predicted and measured heat transfer coefficient was within ±30%.

  1. Simulation of refrigerant phase equilibria

    SciTech Connect

    Gow, A.S. [Univ. of New Haven, CT (United States). Dept. of Chemistry and Chemical Engineering] [Univ. of New Haven, CT (United States). Dept. of Chemistry and Chemical Engineering; Guo, X. [Clarkson Univ., Potsdam, NY (United States). Dept. of Chemical Engineering] [Clarkson Univ., Potsdam, NY (United States). Dept. of Chemical Engineering; Liu, D.; Lucia, A. [Univ. of Rhode Island, Kingston, RI (United States). Dept. of Chemical Engineering] [Univ. of Rhode Island, Kingston, RI (United States). Dept. of Chemical Engineering

    1997-07-01

    Vapor-liquid equilibria for refrigerant mixtures modeled by an equation of state are studied. Phase behavior calculated by the Soave-Redlich-Kwong (SRK) equation with a single adjustable binary interaction parameter is compared with experimental data for binary refrigerant mixtures, two with a supercritical component and one that exhibits azeotropic behavior. It is shown that the SRK equation gives an adequate description of the phase envelope for binary refrigerant systems. The complex domain trust region methods of Lucia and co-workers are applied to fixed vapor, isothermal flash model equations, with particular attention to root finding and root assignment at the equation of state (EOS) level of the calculations, and convergence in the retrograde and azeotropic regions of the phase diagram. Rules for assigning roots to the vapor and liquid phases in the case where all roots to the EOS are complex-valued are proposed and shown to yield correct results, even in retrograde regions. Convergence of the flash model equations is also studied. It is shown that the complex domain trust region algorithms outperform Newton`s method in singular regions of the phase diagram (i.e., at near azeotropic conditions and in the retrograde loop), primarily due to the eigenvalue-eigenvector decomposition strategy given in Sridhar and Lucia (1995). A variety of geometric figures are used to illustrate salient points.

  2. Experimental study and analysis on components of a thermoacoustic refrigerator and thermoacoustic prime mover

    SciTech Connect

    Nohtomi, Makoto; Katsuta, Masafumi

    1999-07-01

    A thermoacoustic refrigerator and a thermoacoustic prime mover, due to its simple structure, would serve as very desirable systems because thermoacoustic prime movers can be driven with the waste heat such as an exhaust gas from engines, and with heat from the nature such as sunlight and a geothermal heat. The thermoacoustic refrigerator and the thermoacoustic prime mover combined would serve as a perfect cooling system without moving parts, CFC's and HFC's. Thus this Thermoacoustic-driven Thermoacoustic Refrigerator will replace the previous paper compression refrigeration system. The authors set up the thermoacoustic refrigerator and thermoacoustic prime mover to investigate the fundamental characteristics. On the refrigerator tests, dimensions of the stack are varied as a parameter of experiments. As a result, influences of the stack configuration on the performance are confirmed, so the design method for the optimum dimension to attain the large temperature difference can be indicated. About the prime mover tests, fundamental characteristics of stack dimensions is checked. The way to improve the thermal efficiency of the prime mover is mentioned in terms of the operating condition. Numerical calculations about the refrigerator are made which is based on the enthalpy flow model by Radebaugh. The result of calculations has a good agreement in quality with the experimental results, so the propriety of this model is confirmed.

  3. Refrigerating machine oil

    SciTech Connect

    Nozawa, K.

    1981-03-17

    Refrigerating machine oil to be filled in a sealed motorcompressor unit constituting a refrigerating cycle system including an electric refrigerator, an electric cold-storage box, a small-scaled electric refrigerating show-case, a small-scaled electric cold-storage show-case and the like, is arranged to have a specifically enhanced property, in which smaller initial driving power consumption of the sealed motor-compressor and easier supply of the predetermined amount of the refrigerating machine oil to the refrigerating system are both guaranteed even in a rather low environmental temperature condition.

  4. Superfluid Joule–Thomson Refrigeration, a New Concept for Cooling Below 2 Kelvin

    Microsoft Academic Search

    J. G. Brisson

    2000-01-01

    A new type of sub-Kelvin refrigerator, the superfluid Joule–Thomson refrigerator is discussed. The refrigerator uses the circulation of the 3He component of a liquid 3He–4He mixture through a throttle to provide cooling to temperatures of 0.5 K. A simple analytical model is developed to predict the cooling power for this refrigerator as function of temperature. In addition, cooling power predictions

  5. ALTERNATIVES FOR OZONE-DEPLETING REFRIGERANTS

    EPA Science Inventory

    The paper gives results of tests of 2 of 11 compounds and several mixtures selected for intensive evaluation from about 40 new synthesized compounds that may serve as environmentally safe and effective refrigerant alternatives over the long term. he two compounds are: 1, 1, 1, 2,...

  6. Molecular modeling of fluoropropene refrigerants.

    PubMed

    Raabe, Gabriele

    2012-05-17

    Different fluoropropenes are currently considered as refrigerants, either as pure compounds or as components in low GWP (global warming potential) refrigerant mixtures. Due to their limited commercial production, experimental data for the thermophysical properties of fluoropropenes and their mixtures are in general rare, which hampers the exploration of their performance in technical applications. In principle, molecular simulation can be used to predict the relevant properties of refrigerants and refrigerant blends, provided that adequate intermolecular potential functions ("force fields") are available. In our earlier work (Raabe, G.; Maginn, E. J., J. Phys. Chem. B2010, 114, 10133-10142), we introduced a transferable force field for fluoropropenes comprising the compounds 3,3,3-trifluoro-1-propene (HFO-1243zf), 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), and hexafluoro-1-propene (HFO-1216). In this paper, we provide an extension of the force field model to the trans- and cis-1,3,3,3-tetrafluoro-1-propene (HFO-1234ze(E), HFO-1234ze) and the cis-1,2,3,3,3-pentafluoro-1-propene (HFO-1225ye(Z)) as well as revised simulation results for HFO-1216. We present Gibbs ensemble simulation results on the vapor pressures, saturated densities, and heats of vaporization of these compounds in comparison with experimental results. The simulation results show that the force field model enables reliable predictions of the properties of the different fluoropropenes and also reproduces well the differing vapor-liquid coexistence and vapor pressure curve of the cis- and trans-isomers of 1,3,3,3-tetrafluoro-1-propene, HFO-1234ze and HFO-1234ze(E). For these two isomers, we also present molecular dynamics simulation studies on their local structure. PMID:22519953

  7. Compatibility of refrigerants and lubricants with elastomers. Final report

    SciTech Connect

    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 II 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.

  8. Refrigeration for Cryogenic Sensors

    SciTech Connect

    Gasser, M.G.

    1983-12-01

    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.

  9. 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.

  10. ARTI Refrigerant Database

    SciTech Connect

    Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

    1994-05-27

    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.

  11. HFC-134a emissions from mobile air conditioning in China from 1995 to 2030

    NASA Astrophysics Data System (ADS)

    Su, Shenshen; Fang, Xuekun; Li, Li; Wu, Jing; Zhang, Jianbo; Xu, Weiguang; Hu, Jianxin

    2015-02-01

    Since 1995, 1,1,1,2-tetrafluoroethane (CH2FCF3, HFC-134a) has become the most important substitute of CFC-12 in mobile air conditioning (MAC) in China and MAC sector has dominated all the emissions of HFC-134a. In this study, we developed an accurate, updated and county-level inventory of the HFC-134a emissions from MAC in China for the period of 1995-2030 with an improved bottom-up method. Our estimation indicated that the total HFC-134a emissions kept growing at increase rates of ?100% per year for 1995-2000 and ?34% per year for 2001-2010. In 2010, HFC-134a emissions from MAC in China reached 16.7 Gg (10.5-22.7 Gg at 95% confidential interval), equivalent to 21.7 Tg CO2 (CO2-eq). Furthermore, the emissions in China estimated in this study accounted for 9.8% of global HFC-134a emissions and 29.0% of total emissions from Non-Annex_I countries in 2010. Due to the more advanced social-economic conditions and more intensive ownership of automobiles, greater HFC-134a were observed to come from big cities in East China. Under a Business-as-usual (BAU) Scenario, projected emissions will grow to 89.4 (57.9-123.9) Gg (about 75.3-161.1 Tg CO2-eq) in 2030, but under an Alternative Scenario, 88.6% of the projected emissions under BAU scenario could be curbed. Our estimation demonstrates huge emission mitigation potential of HFC-134a in China's MAC sector.

  12. The superfluid Stirling refrigerator, a new method for cooling below 0.5 K

    SciTech Connect

    Brisson, J.G.; Kotsubo, V.; Swift, G.W.

    1993-04-09

    A new subkelvin refrigerator, the superfluid Stirling cycle refrigerator, uses a working fluid of {sup 3}He-{sup 4}He mixture in a Stirling cycle. The thermodynamically active components of the mixture are the {sup 3}He, which behaves like a Boltzman gas, and the phonon-roton gas in the {sup 4}He. The superfluid component of the liquid is inert. Two refrigerators have been built and temperatures of 340 mK have been achieved.

  13. The superfluid Stirling refrigerator, a new method for cooling below 0. 5 K

    SciTech Connect

    Brisson, J.G.; Kotsubo, V.; Swift, G.W.

    1993-04-09

    A new subkelvin refrigerator, the superfluid Stirling cycle refrigerator, uses a working fluid of [sup 3]He-[sup 4]He mixture in a Stirling cycle. The thermodynamically active components of the mixture are the [sup 3]He, which behaves like a Boltzman gas, and the phonon-roton gas in the [sup 4]He. The superfluid component of the liquid is inert. Two refrigerators have been built and temperatures of 340 mK have been achieved.

  14. The superfluid Stirling refrigerator, a new method for cooling below 0.5 K

    Microsoft Academic Search

    J. G. Brisson; V. Kotsubo; G. W. Swift

    1994-01-01

    A new sub-Kelvin refrigerator, the superfluid Stirling cycle refrigerator, uses a working fluid of 3He-4He mixture in a Stirling cycle. The thermodynamically active components of the mixture are the 3He, which behaves like a Boltzmann gas, and the phonon-roton gas in the 4He. The superfluid component of the liquid is inert. Two refrigerators have been built, and temperatures of 340

  15. The superfluid Stirling refrigerator, a new method for cooling below 0.5 K

    Microsoft Academic Search

    J. G. Brisson; V. Kotsubo; G. W. Swift

    1993-01-01

    A new subkelvin refrigerator, the superfluid Stirling cycle refrigerator, uses a working fluid of He-3\\/He-4 mixture in a Stirling cycle. The thermodynamically active components of the mixture are the He-3, which behaves like a Boltzman gas, and the phonon-proton gas in the He-4. The superfluid component of the liquid is inert. Two refrigerators have been built and temperatures of 340

  16. Optimize refrigeration design

    Microsoft Academic Search

    Baggio

    1984-01-01

    Design of a propane refrigeration system using an economizer can be determined quickly by using a nomograph. Usually selection of economizer operating conditions and resulting requirements for compression are based on time consuming iterative calculations. These can be avoided and optimum operating conditions set with comparative ease using the nomograph. A simplified refrigeration system involves evaporation of propane refrigerant at

  17. Thermoacoustic Refrigerator's Stack Optimization

    Microsoft Academic Search

    Mawahib Hassan El-Fawal; Normah Mohd-Ghazali; Mohd. Shafik Yaacob; Amer Nordin Darus

    2010-01-01

    The standing wave thermoacoustic refrigerator, which uses sound generation to transfer heat, was developed rapidly during the past four decades. It was regarded as a new, promising and environmentally benign alternative to conventional compression vapor refrigerators, although it was not competitive regarding the coefficient of performance (COP) yet. Thus the aim of this paper is to enhance thermoacoustic refrigerator's stack

  18. Japanese refrigerators field testing

    Microsoft Academic Search

    1989-01-01

    Residential refrigerators consume the equivalent of 1700 megawatts (MW) of baseload power in the Bonneville Power Administration (BPA) service area. Japanese manufacturers have designed refrigerator units that appear more energy efficient than some currently available American models. This report summarizes preliminary findings from field testing of 12 refrigerators of Japanese manufacture to evaluate annual kilowatt hour (kWh) use during actual

  19. Japanese Refrigerators Field Testing

    Microsoft Academic Search

    Albert T

    1989-01-01

    Residential refrigerators consume the equivalent of 1700 megawatts (MW) of baseload power in the Bonneville Power Administration (BPA) service area. Japanese manufacturers have designed refrigerator units that appear more energy efficient than some currently available American models. This report summarizes preliminary findings from field testing of 12 refrigerators of Japanese manufacture to evaluate annual kilowatt hour (kWh) use during actual

  20. Solar Powered Refrigeration System

    Microsoft Academic Search

    Michael K. Ewert; David J. Bergeron III

    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

  1. Determining rate of refrigerant emissions from nonprofessional automotive service through a southern California field study

    NASA Astrophysics Data System (ADS)

    Zhan, Tao; Clodic, Denis; Palandre, Lionel; Trémoulet, Arnaud; Riachi, Youssef

    2013-11-01

    Vehicle owners in the United States can recharge their vehicles' air conditioning systems with small containers of hydrofluorocarbon-134a (HFC-134a, CH2FCF3). This refrigerant, with a Global Warming Potential of 1430, may be emitted to the atmosphere during the recharging operation and from the residual heel in partially used containers, contributing to climate change. A field study was conducted in southern California to quantify the rate of refrigerant emissions from nonprofessional recharging practices and identify emission mitigation opportunities. Based on the results of the study, an average of 489 g of HFC-134a is used when recharging the sample vehicles with an average nominal charge of 858 g. An average 67% of the container content is effectively charged into the systems, 11% of the refrigerant is released during service, and the remaining 22% is left in the containers after operations are completed. A comparison with two other independent studies indicates that the findings of the current study may be applicable not only to southern California, but also to the entire U.S.

  2. Zero ODP HFC Blowing Agents for Appliance Foam

    Microsoft Academic Search

    Herman P. Doerge

    1997-01-01

    Although HCFC-141b has been selected as the best replacement for the blowing agent CFC-11 used in refrigerator or freezer foams in North America, it is only an interim solution in the ongoing efforts to replace CFCs. Under investigation are hydrofluorocarbons (HFCs) which have zero ozone depletion potential (ODP). Papers have been presented at SPI conferences in 1991 and 1993 on

  3. Non-inert refrigerant study for automotive applications

    SciTech Connect

    Dieckmann, J.T.; Bentley, J.; Varone, A.

    1991-11-01

    Alternatives to CFC-12 for automobile air conditioning were examined. The list of candidate fluids included flammable as well as non-flammable substances. HFC-134a was taken as the baseline alternative given current industry plans to convert automobile air conditioning systems to this fluid over the next several years. Three flammable (non-inert) altemative refrigerants -- BFC-152a, HC-290 (propane) and HC-270 (cyclopropane) were identified. Air conditioning cycle efficiency, ozone depletion potential, and global warming impacts of these three fluids and HFC-134a were compared, with the three non-inert fluids all having higher COP and lower global warming impact. The ozone depletion potential of each of these fluids is zero. The fire safety implications of the flammable alternatives being used in otherwise conventional automobile air conditioning systems were examined in preliminary fashion. The results, which are subject to more extensive verification indicate that the additional passenger compartment fire risk would be very small, while the incidence of engine compartment fires would increase modestly. The engine compartment fire hazard could be minimized by modest design changes to reduce the occurrence of ignition sources and condenser punctures in front end collisions.

  4. Optimal synthesis of refrigeration cycles and selection of refrigerants

    Microsoft Academic Search

    Shankar Vaidyaraman; Costas D. Maranas

    1999-01-01

    The optimal synthesis of the refrigeration configuration and the selection of the best refrigerants that satisfy a set of process cooling duties at different temperatures is addressed. This approach simultaneously selects refrigerants and synthesizes refrigeration structures by minimizing a weighted sum of investment and operating costs. A superstructure representation considers the majority of refrigeration cycle features encountered in real complex

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

    SciTech Connect

    Abdelaziz, Omar [ORNL] [ORNL; Fricke, Brian A [ORNL] [ORNL; Vineyard, Edward Allan [ORNL] [ORNL

    2012-01-01

    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; system 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.

  6. HFC-134a Emissions in China: An Inventory for 1995-2030

    NASA Astrophysics Data System (ADS)

    Su, Shenshen; Fang, Xuekun; Wu, Jing; Li, Li; Hu, Jianxin; Han, Jiarui

    2014-05-01

    HFC-134a is the most important substitute of CFC-12 used in the mobile air-conditioner in China since 1995. The bottom-up method was used to estimate HFC-134a emissions in China, from 1995 to 2030, basing on updated automobile industry data and latest emission characters. From 1995, total HFC-134a emission has kept a high growth rate of nearly 60% per year, and reached 16,414.3 Mg (11,959.4-20,834.5 Mg) in 2010, which was equivalent to 23.5 Mt CO2-eq emissions. Furthermore, the emissions in China accounted for nearly half of total emissions of Non-AnnexI countries in 2008. As for provincial emissions in 2010, provinces with emission greater than 1,000 Mg are Guangdong, Shandong, Jiangsu and Beijing. Quantitative relationship between provincial HFC-134a emissions and GRP of the Tertiary Industry was used to estimate HFC-134a emissions at county level, and Hangzhou municipal district held the maximum emission intensity (4,605 Mg/10,000 km2). For HFC-134a, emissions calculated from the observations within 46 cities through Euler box model are in good agreement with the corresponding emissions estimated from the bottom-up method, verifying that the emission inventory at county level adequately describes the emission spatial pattern. For the future emissions of HFC-134a, projected emissions will reach 89,370.4 Mg (65,959.7- 114,068.2 Mg) in 2030 under the Business-as-usual (BAU) Scenario, but under the Alternative Scenario, a emission reduction potential of 88.6% of the projected BAU emissions would be obtained.

  7. Dryout Quality for Refrigerants Flowing in Horizontal Evaporator Tubes

    NASA Astrophysics Data System (ADS)

    Mori, Hideo; Kakimoto, Yasushi; Ohishi, Katsumi

    The present paper reports an investigation of the dryout quality for refrigerants flowing in horizontal evaporator tubes. Experiments were made for the flow of boiling HFC-134a and HCFC-22 inside smooth tubes and a spirally grooved (micro-fin) tube. At given conditions, dryout proceeded over a certain quality range. Therefore two dryout qualities were defined; dryout inception quality at which the circumferentially averaged (axially local) heat transfer coefficient began to decrease rapidly, and dryout completion quality at which the decrease in the heat transfer coefficient ended. Based on the experimental data, the characteristics of both dryout qualities were clarified, and thereby the dryout qualities were classified into three characteristic regimes for the smooth tube and two regimes for the micro-fin tube. A dimensionless correlation of each dryout quality, which can reproduce the measurement successfully, was developed for the respective tubes.

  8. Miscibility of lubricants with refrigerants, Phase 1

    SciTech Connect

    Pate, M.B.; Zoz, S.C.; Berkenbosch, L.J. (Iowa State Univ. of Science and Technology, Ames, IA (United States). Dept. of Agricultural Engineering)

    1992-10-01

    Miscibility data have been obtained for a variety of non-CFC refrigerants and their potential lubricants. Ten different refrigerants and seven different lubricants were investigated. Experiments are being performed in two phases: Phase I, reported herein, focuses on performing screening tests for miscibility and Phase II consists of developing miscibility plots. The miscibility tests are being performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The bath temperature can be precisely controlled over a temperature range of -50 C to 90C(-58 F to 194 F). The test cells are constructed to allow for complete visibility of lubricant-refrigerant mixtures under all test conditions.

  9. Refrigerator Based on Chemisorption

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1987-01-01

    Reversible chemical reaction generates pressurized oxygen for cooling. Concept for cryogenic refrigerator based on chemical absorption of oxygen by praseodymium/cerium oxide (PCO) compound. Refrigerator produces cryogenic liquid for cooling infrared sensors. Also used for liquefying air and separating oxygen from nitrogen in air. In chemisorption refrigerator, PCO alternately absorbs and desorbs oxygen depending on whether cooled or heated. One pair of compressors accepts oxygen while others releases it. Compressed oxygen liquefied when precooked and expanded.

  10. Chemically assisted mechanical refrigeration process

    DOEpatents

    Vobach, Arnold R. (6006 Allentown Dr., Spring, TX 77389)

    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.

  11. Chemically assisted mechanical refrigeration process

    DOEpatents

    Vobach, Arnold R. (6006 Allentown Dr., Spring, TX 77379)

    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.

  12. Assessment of Environmentally Friendly Refrigerants for Window Air Conditioners

    SciTech Connect

    Bansal, Pradeep [ORNL] [ORNL; Shen, Bo [ORNL] [ORNL

    2014-01-01

    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 their suitability for window air conditioners.

  13. Refrigerants in Transition 

    E-print Network

    Stouppe, D. E.

    1991-01-01

    Potential 1.0 1.0 0.8 * 1.0 'j( 0.6 * 0.05 0.02 0.02 o o o 0.8 0.3 Ozone Depletion Potential Refrigerant ~lanyfactors determine the suitability of a chemical for use as a refrigerant or for the other purposes that CFCs were used. Thermodynamic properties... priority item. OTHER REFRIGERANTS/TECHNOLOGIES What else is available? Before the invention of CFCs other compounds were used successfully and safely for refrigeration. Hydrocarbons such as methane and butane, sulfur dioxide and ammonia are Table II...

  14. Quantifying Regional Greenhouse Gas Emissions of HFC-134a From Atmospheric Measurements at the Trinidad Head (California), Cape Grim (Tasmania) and Mace Head (Ireland) Remote AGAGE Sites.

    NASA Astrophysics Data System (ADS)

    Manning, A. J.; Weiss, R. F.; Mühle, J.; Fraser, P. J.; Krummel, P. B.; O'Doherty, S.; Simmonds, P. G.

    2008-12-01

    Atmospheric measurement-based "top-down" approaches to emissions estimation provide a method of validating reported inventory-based "bottom-up" emissions assessments. At the AGAGE (Advanced Global Atmospheric Gases Experiment) measurement stations at Trinidad Head (THD) on the Northern California coast (41°N, 124°W), Cape Grim (CGM) on the northwestern tip of Tasmania (41°S, 145°E), and Mace Head (MHD) on the western coast of Ireland (53°N, 10°W), Medusa GC/MS and GC/ECD/FID instrumentation measure a wide range of trace gases in ambient air at high temporal resolution and high precision. Here, the western US, northwestern European and southern Australian emissions of the greenhouse gas (GHG) HFC-134a are estimated using the HFC-134a measurements, an atmospheric dispersion model (NAME), and an inversion methodology. NAME (Numerical Atmospheric dispersion Modelling Environment) is a Lagrangian atmospheric dispersion model that uses 3D meteorology from the UK Met Office numerical weather prediction model. Mid-latitude Northern and Southern Hemisphere baseline concentrations of HFC-134a are determined using NAME and statistical post- processing of the observations, and this baseline is used to generate a time series of "polluted" (above baseline) observations. In this application NAME is run backwards in time for ten days for each 3-hour interval in 1995-2008 for MHD, 2003-2008 for CGM and 2005-2008 for THD releasing thousands of model particles at each observing site. A map is then produced estimating all of the surface (0-100m) contributions within ten days of travel arriving at each site during each interval. The resulting matrix describes the dilution in concentration that occurs from a unit release from each grid as it travels to the measurement site. Iterative inversion modeling is then carried out to generate an emission estimate that provides the best statistical match between the modeled time series and the observations. Uncertainty in the emission estimates is captured by starting each solution from a randomly generated emission map, randomly perturbing the observations by a noise factor, and solving the inversion eight times using two different skill score (cost) functions. Solutions are found for each 24-month period (Jan-Dec, Feb-Jan, etc.) within the timescales given. The estimated emission distributions pick out most of the significant populated areas and estimates very low emissions from the ocean areas. This is consistent with the understanding that HFC-134a is emitted broadly in line with population as it is widely used as a refrigerant, e.g. in car air conditioners. The results using MHD show that the emissions of HFC-134a in northwestern Europe have increased sharply over the past 14 years. The emissions per head of population for each 24-month period from each of the different geographical regions are compared. The emissions for each area are also scaled up to country (USA and Australia) and collective countries (EU-15) totals based on population and compared with UNFCCC inventory estimates.

  15. An evaluation on the environmental consequences of residual CFCs from obsolete household refrigerators in China

    SciTech Connect

    Zhao Xiangyang; Duan Huabo [Department of Environmental Science and Engineering, Tsinghua University, Beijing (China); Li Jinhui, E-mail: jinhui@tsinghua.edu.cn [Department of Environmental Science and Engineering, Tsinghua University, Beijing (China)

    2011-03-15

    Chlorofluorocarbons (CFCs) contained in household refrigerators consist mainly of CFC-11 and CFC-12, which will be eventually released into the environment. Consequentially, environmental releases of these refrigerants will lead to ozone depletion and contribute significantly to the greenhouse effect, if waste refrigerators are not disposed of properly. In the present paper, the potential release of residual CFCs and their substitutes from obsolete household refrigerators in China is examined, and their contributions to ozone depletion and greenhouse effect are compared with those of other recognized ozone-depleting substances (ODS) and greenhouse gases (GHGs). The results imply that annual potential amounts of released residual CFC-11 and CFC-12 will reach their maximums at 4600 and 2300 tons, respectively in 2011, and then decrease gradually to zero until 2020. Meanwhile, the amounts of their most widely used substitutes HCFC-141b and HFC-134a will keep increasing. Subsequently, the contribution ratio of these CFCs and their substitutes to ozone depletion will remain at 25% through 2011, and reach its peak value of 34% by 2018. The contribution to greenhouse effect will reach its peak value of 0.57% by 2010. Moreover, the contribution ratio of these CFCs to the total global release of CFCs will steadily increase, reaching its peak of 15% by 2018. Thus, this period from 2010 to 2018 is a crucial time during which residual CFCs and their substitutes from obsolete household refrigerators in China will contribute significantly to ozone depletion.

  16. An evaluation on the environmental consequences of residual CFCs from obsolete household refrigerators in China.

    PubMed

    Zhao, Xiangyang; Duan, Huabo; Li, Jinhui

    2011-03-01

    Chlorofluorocarbons (CFCs) contained in household refrigerators consist mainly of CFC-11 and CFC-12, which will be eventually released into the environment. Consequentially, environmental releases of these refrigerants will lead to ozone depletion and contribute significantly to the greenhouse effect, if waste refrigerators are not disposed of properly. In the present paper, the potential release of residual CFCs and their substitutes from obsolete household refrigerators in China is examined, and their contributions to ozone depletion and greenhouse effect are compared with those of other recognized ozone-depleting substances (ODS) and greenhouse gases (GHGs). The results imply that annual potential amounts of released residual CFC-11 and CFC-12 will reach their maximums at 4600 and 2300 tons, respectively in 2011, and then decrease gradually to zero until 2020. Meanwhile, the amounts of their most widely used substitutes HCFC-141b and HFC-134a will keep increasing. Subsequently, the contribution ratio of these CFCs and their substitutes to ozone depletion will remain at 25% through 2011, and reach its peak value of 34% by 2018. The contribution to greenhouse effect will reach its peak value of 0.57% by 2010. Moreover, the contribution ratio of these CFCs to the total global release of CFCs will steadily increase, reaching its peak of 15% by 2018. Thus, this period from 2010 to 2018 is a crucial time during which residual CFCs and their substitutes from obsolete household refrigerators in China will contribute significantly to ozone depletion. PMID:21093246

  17. Recovering and reusing refrigerants

    Microsoft Academic Search

    Katzel

    1994-01-01

    Chlorofluorocarbons (CFCs) and, to a much lesser extent, hydrochlorofluorocarbons (HCFCs), are believed to be a major cause of ozone depletion. The lifeblood of most air conditioning and refrigeration equipment, these chemical compounds have provided a safe, economical mechanism for transferring heat for decades. Today, CFCs are virtually on their deathbeds. To cope with the unavailability of previously abundant refrigerants, plant

  18. Stirling-cycle refrigerator

    Microsoft Academic Search

    Nakamura

    1985-01-01

    A Stirling-cycle refrigerator comprises a plurality of Stirling-cycle refrigerator units each having a displacer defining an expansion chamber, a piston defining a compression chamber, and a circuit including a heater and a cooler and interconnecting the expansion chamber and the compression chamber, and a heat exchanger shared by the circuits and disposed between the coolers and the heaters for effecting

  19. A solar thermoelectric refrigerator

    Microsoft Academic Search

    G. J. Vella; L. B. Harris; H. J. Goldsmid

    1976-01-01

    It is shown that a thermoelectric generator, which draws its heat from the sun, is a particularly suitable source of electrical power for the operation of a thermoelectric refrigerator. The theory of the combined thermoelectric generator and refrigerator is derived, and the ratio of the numbers of thermocouples needed for the two devices is determined. It is found that this

  20. Solar thermoelectric refrigerator

    Microsoft Academic Search

    G. J. Vella; L. B. Harris; H. J. Goldsmid

    1976-01-01

    It is shown that a thermoelectric generator, which draws its heat from the sun, is a particularly suitable source of electrical power for the operation of a thermoelectric refrigerator. The theory of the combined thermoelectric generator and refrigerator is derived and the ratio of the numbers of thermocouples needed for the two devices is determined. It is found that this

  1. 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.

  2. ARTI Refrigerant Database

    SciTech Connect

    Calm, J.M.

    1992-04-30

    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, though some may be added at a later date. The database identifies sources of specific information on R-32, R-123, R-124, R- 125, R-134a, R-141b, R142b, R-143a, R-152a, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses polyalkylene glycol (PAG), ester, and other lubricants. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits.

  3. Near azeotropic mixture substitute

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1996-01-01

    The present invention comprises a refrigerant mixture consisting of a first mole fraction of 1,1,1,2-tetrafluoroethane (R134a) and a second mole fraction of a component selected from the group consisting of a mixture of CHClFCF.sub.3 (R124) and CH.sub.3 CClF.sub.2 (R142b); a mixture of CHF.sub.2 CH.sub.3 (R152a) and CHClFCF.sub.3 (R124); a mixture of CHF.sub.2 CH.sub.3 (R152a) and CH.sub.3 CClF.sub.2 (R142b); and a mixture of CHClFCF.sub.3 (R124), CH.sub.3 CClF.sub.2 (R142b) and CHF.sub.2 CH.sub.3 (R152a).

  4. Screening analysis for chlorine-free alternative refrigerants to replace R-22 in air conditioning applications

    Microsoft Academic Search

    S. K. Fischer; J. R. Sand

    1993-01-01

    The potential health and environmental effects of the depletion of stratospheric ozone from refrigerants containing chlorine have resulted in international treaties, laws, and non-binding agreements to phase-out and eliminate many common refrigerants. R-22 is one of these compounds. A study was conducted to evaluate the potential of twenty-two chlorine-free compounds in refrigerant mixtures of up to three components as substitutes

  5. Piezoelectrically-driven Thermoacoustic Refrigerator

    Microsoft Academic Search

    Daniel George Chinn

    2010-01-01

    Thermoacoustic refrigeration is an emerging refrigeration technology which does not require any moving parts or harmful refrigerants in its operation. This technology uses acoustic waves to pump heat across a temperature gradient. The vast majority of thermoacoustic refrigerators to date have used electromagnetic loudspeakers to generate the acoustic input. In this thesis, the design, construction, operation, and modeling of a

  6. Wednesday, September 17, 2014 Shroyer Gym, HFC Fitness Center Nordic Walking 101 Brain Workout Workshop

    E-print Network

    Maxwell, Bruce D.

    -on workshop is accompanied with seminar style learning to get you up and moving. Nordic Walking 201Wednesday, September 17, 2014 Shroyer Gym, HFC Fitness Center Nordic Walking 101 Brain Workout & is the only person to have walked 11,208 miles through all 50 states in 365 straight days. Robert is also

  7. HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION

    EPA Science Inventory

    The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned [1024- and 1575-fpm (...

  8. HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION

    EPA Science Inventory

    The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned (1024- and 1575-fpm (...

  9. Elevated temperature ablation resistance of HfC particle-reinforced tungsten composites

    E-print Network

    Hong, Soon Hyung

    Keywords: Composite materials Powder metallurgy Sintering Ablation properties Microstructure The effects in a refractory metal matrix has yielded composites with an interesting set of chemical, thermal, and mechanical fabricated tungsten matrix composites containing large volume fractions of HfC using the powder metallurgy

  10. Deployment of Live-Video Services Based on Streaming Technology over an HFC Network

    Microsoft Academic Search

    David Melendi; Xabiel G. Pañeda; Roberto García; Ricardo Bonis; Víctor G. García

    2004-01-01

    1 Abstract: This paper presents an approach to the deployment of a live-video service based on streaming technology over an HFC network. This approach covers most of the issues that may arise while putting one of these services into operation, taking into account new aspects such as those oriented to the improvement and prior analysis of the service's behaviour. An

  11. Pulse Tube Refrigerator

    NASA Astrophysics Data System (ADS)

    Matsubara, Yoichi

    The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.

  12. Future emissions and atmospheric fate of HFC-1234yf from mobile air conditioners in Europe.

    PubMed

    Henne, Stephan; Shallcross, Dudley E; Reimann, Stefan; Xiao, Ping; Brunner, Dominik; O'Doherty, Simon; Buchmann, Brigitte

    2012-02-01

    HFC-1234yf (2,3,3,3-tetrafluoropropene) is under discussion for replacing HFC-134a (1,1,1,2-tetrafluoroethane) as a cooling agent in mobile air conditioners (MACs) in the European vehicle fleet. Some HFC-1234yf will be released into the atmosphere, where it is almost completely transformed to the persistent trifluoroacetic acid (TFA). Future emissions of HFC-1234yf after a complete conversion of the European vehicle fleet were assessed. Taking current day leakage rates and predicted vehicle numbers for the year 2020 into account, European total HFC-1234yf emissions from MACs were predicted to range between 11.0 and 19.2 Gg yr(-1). Resulting TFA deposition rates and rainwater concentrations over Europe were assessed with two Lagrangian chemistry transport models. Mean European summer-time TFA mixing ratios of about 0.15 ppt (high emission scenario) will surpass previously measured levels in background air in Germany and Switzerland by more than a factor of 10. Mean deposition rates (wet + dry) of TFA were estimated to be 0.65-0.76 kg km(-2) yr(-1), with a maxium of ?2.0 kg km(-2) yr(-1) occurring in Northern Italy. About 30-40% of the European HFC-1234yf emissions were deposited as TFA within Europe, while the remaining fraction was exported toward the Atlantic Ocean, Central Asia, Northern, and Tropical Africa. Largest annual mean TFA concentrations in rainwater were simulated over the Mediterranean and Northern Africa, reaching up to 2500 ng L(-1), while maxima over the continent of about 2000 ng L(-1) occurred in the Czech Republic and Southern Germany. These highest annual mean concentrations are at least 60 times lower than previously determined to be a safe level for the most sensitive aquatic life-forms. Rainwater concentrations during individual rain events would still be 1 order of magnitude lower than the no effect level. To verify these results future occasional sampling of TFA in the atmospheric environment should be considered. If future HFC-1234yf emissions surpass amounts used here studies of TFA accumulation in endorheic basins and other sensitive areas should be aspired. PMID:22225403

  13. Binary refrigerant–oil phase equilibrium using the simplified SAFT equation

    Microsoft Academic Search

    Angelo Lucia; Qing Luo

    2002-01-01

    Refrigerants such as tetrafluoroethane (R134a) with compatible oils such as polyalkaline glycols (PAGs) and neopentyl (polyol) esters are now being used as replacements for CFCs like freons in household and automobile compressors as well as a number of other applications. Thus an understanding and accurate quantitative description of the phase equilibrium behavior of binary refrigerant–oil mixtures is important. For example,

  14. Performance and heat transfer characteristics of hydrocarbon refrigerants in a heat pump system

    Microsoft Academic Search

    Y. S Chang; M. S Kim; S. T Ro

    2000-01-01

    Performance of a heat pump system using hydrocarbon refrigerants has been investigated experimentally. Single component hydrocarbon refrigerants (propane, isobutane, butane and propylene) and binary mixtures of propane\\/isobutane and propane\\/butane are considered as working fluids in a heat pump system. The heat pump system consists of compressor, condenser, evaporator, and expansion device with auxiliary facilities such as evacuating and charging unit,

  15. Thermoacoustic engines and refrigerators

    SciTech Connect

    Swift, G.

    1996-12-31

    This report is a transcript of a practice lecture given in preparation for a review lecture on the operation of thermoacoustic engines and refrigerators. The author begins by a brief review of the thermodynamic principles underlying the operation of thermoacoustic engines and refrigerators. Remember from thermodynamics class that there are two kinds of heat engines, the heat engine or the prime mover which produces work from heat, and the refrigerator or heat pump that uses work to pump heat. The device operates between two thermal reservoirs at temperatures T{sub hot} and T{sub cold}. In the heat engine, heat flows into the device from the reservoir at T{sub hot}, produces work, and delivers waste heat into the reservoir at T{sub cold}. In the refrigerator, work flows into the device, lifting heat Q{sub cold} from reservoir at T{sub cold} and rejecting waste heat into the reservoir at T{sub hot}.

  16. Joule Thomson refrigerator

    NASA Technical Reports Server (NTRS)

    Chan, Chung K. (inventor); Gatewood, John R. (inventor)

    1988-01-01

    A bi-directional Joule Thomson refrigerator is described, which is of simple construction at the cold end of the refrigerator. Compressed gas flowing in either direction through the Joule Thomson expander valve and becoming liquid, is captured in a container in direct continuous contact with the heat load. The Joule Thomson valve is responsive to the temperature of the working fluid near the valve, to vary the flow resistance through the valve so as to maintain a generally constant flow mass between the time that the refrigerator is first turned on and the fluid is warm, and the time when the refrigerator is near its coldest temperature and the fluid is cold. The valve is operated by differences in thermal coefficients of expansion of materials to squeeze and release a small tube which acts as the expander valve.

  17. Mixed refrigerants for a glass capillary micro cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Lin, M.-H.; Bradley, P. E.; Huber, Marcia L.; Lewis, R.; Radebaugh, R.; Lee, Y. C.

    2010-08-01

    Optimized mixed refrigerants are applied in Joule-Thomson (JT) micro cryogenic coolers (MCC) to enhance efficiency. Mixed refrigerants deliver equivalent refrigeration power with much lower pressure ratio and flow rate compared to pure nitrogen refrigerant. To determine the behavior of mixtures in MCCs, the normal boiling points of the components, mixture solubility, and refrigeration loss due to pressure drop on the low-pressure side of the heat exchanger are evaluated. The MCC discussed here was designed to operate at 77 K with the heat exchanger warm end precooled to 240 K by a thermo-electric cooler. An optimized five-component mixed refrigerant was calculated to provide a minimum isothermal enthalpy difference of 1.35 kJ/mol between 77 K and 240 K with a high pressure of 1.6 MPa and a low pressure of 0.1 MPa. Experimentally, a stable temperature of 140 K was achieved with a flow rate of 11 ?mol/s. A transient temperature of 76 K was observed.

  18. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    G. W. Swift; V. Y. Kotsubo

    1991-01-01

    This invention is comprised of a cryogenic refrigerator which cools a heat source by cyclically concentrating and diluting the amount of [sup 3]He in a single phase [sup 3]He\\/[sup 4]He solution. The [sup 3]He in superfluid [sup 4]He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably

  19. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    Gregory W. Swift; Vincent Y. Kotsubo

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of .sup.3 He in a single phase .sup.3 He-.sup.4 He solution. The .sup.3 He in superfluid .sup.4 He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A

  20. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    G. W. Swift; V. Y. Kotsubo

    1991-01-01

    This invention is comprised of a cryogenic refrigerator which cools a heat source by cyclically concentrating and diluting the amount of ³He in a single phase ³He\\/⁴He solution. The ³He in superfluid ⁴He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle.

  1. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    G. W. Swift; V. Y. Kotsubo

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of [sup 3]He in a single phase [sup 3]He-[sup 4]He solution. The [sup 3]He in superfluid [sup 4]He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A

  2. Save with Hybrid Refrigeration 

    E-print Network

    Chung, C. W.

    1985-01-01

    SCHEME A PCR configuration (Fig. 1.) is a conventional scheme to provide multi-level refrigeration. The multi-stage centrifugal compressor, the heart of the unit, boosts the refrigerant pressure to a level where it is condensed, at its dew point... scheme are: Compressor load is reduced by 55%, and after cooler load is reduced by 36% with a corre sponding reduction in equipment size. Compressor design is simplified. Compressor maintenance cost is reduced. Compressor noise level is lower...

  3. Impact of refrigerant–oil solubility on an evaporator performances working with R-407C

    Microsoft Academic Search

    M. Youbi-Idrissi; J. Bonjour; C. Marvillet; F. Meunier

    2003-01-01

    We propose in this study a simplified model of enthalpy calculation for a refrigerant–oil mixture, as well as a new presentation of the pressure–enthalpy–vapour quality diagram which is applied to refrigerant–oil mixtures with different oil circulating mass fractions. This presentation allows the calculation of the enthalpy change through an evaporator, with and without taking into account the effect of oil,

  4. Adsorption of Hydrofluorocarbons HFC-134 and HFC-134A on X and Y Zeolites: Effect of Ion-Exchange on Selectivity and Heat of Adsorption

    E-print Network

    Siperstein, Flor R.

    rapidly as worldwide refrigerator and air-conditioner production rises almost exponentially.1 A byproduct. Gorte, Alan L. Myers,* Clare P. Grey, and David R. Corbin Department of Chemical Engineering, Uni) is a hydrofluorocarbon coolant for refrigerators designated to replace the ozone-damaging chloro- fluorocarbons (CFCs

  5. Refrigeration and Air-Conditioning Technology Workshop

    NASA Astrophysics Data System (ADS)

    Lewis, P. J.; Counce, D. M.

    1993-12-01

    The Alternative Fluorocarbon Environmental Acceptability Study (AFEAS), a consortium of fluorocarbon manufacturers, and the U.S. Department of Energy (DOE) are collaborating on a project to evaluate the energy use and global warming impacts of CFC alternatives. The goal of this project is to identify technologies that could replace the use of CFC's in refrigeration, heating, and air-conditioning equipment; to evaluate the direct impacts of chemical emissions on global warming; and to compile accurate estimates of energy use and indirect CO2 emissions of substitute technologies. The first phase of this work focused on alternatives that could be commercialized before the year 2000. The second phase of the project is examining not-in-kind and next-generation technologies that could be developed to replace CFC's, HCFC's, and HFC's over a longer period. As part of this effort, Oak Ridge National Laboratory held a workshop on June 23-25, 1993. The preliminary agenda covered a broad range of alternative technologies and at least one speaker was invited to make a brief presentation at the workshop on each technology. Some of the invited speakers were unable to participate, and in a few cases other experts could not be identified. As a result, those technologies were not represented at the workshop. Each speaker was asked to prepare a five to seven page paper addressing six key issues concerning the technology he/she is developing. These points are listed in the sidebar. Each expert also spoke for 20 to 25 minutes at the workshop and answered questions from the other participants concerning the presentation and area of expertise. The primary goal of the presentations and discussions was to identify the developmental state of the technology and to obtain comparable data on system efficiencies.

  6. Refrigeration principles and systems: An energy approach

    Microsoft Academic Search

    Pita

    1984-01-01

    The book presents the fundamental principles, systems, and practices of refrigeration. Emphasizing energy conservation, it offers applications of the refrigeration systems and equipment. Topics covered include: physical principles; the vapor compression refrigeration system: Pressure-enthalpy diagrams; thermodynamics of the vapor compression refrigeration cycle; reciprocating, rotary and screw compressors; heat transfer in refrigeration: Evaporators; condensers and cooling towers; refrigerant flow control (expansion)

  7. PERFORMANCE EVALUATION OF A VARIABLE SPEED, MIXED REFRIGERANT HEAT PUMP

    EPA Science Inventory

    The report gives results of an evaluation of the performance of an innovative heat pump, equipped with a distillation column to shift the composition of a zeotropic refrigerant mixture. t gives results of U.S. Department of Energy (DOE) rating tests and seasonal energy calculatio...

  8. Bubble Pump Design for Single Pressure Absorption Refrigeration Cycles

    Microsoft Academic Search

    Sam V. Shelton

    2002-01-01

    A model has been developed for the design and optimiza- tion of a small bubble pump to be used in a single pressure absorption refrigeration cycle to lift the working fluid mixture against gravity and overcome flow friction. This analytical model is developed from two-phase flow fundamentals and incorporates the design parameters of the bubble pump. Para- metric studies are

  9. Conceptual design of binary\\/multicomponent fluid ejector refrigeration systems

    Microsoft Academic Search

    D. Buyadgie; O. Buyadgie; S. Artemenko; A. Chamchine; O. Drakhnia

    2012-01-01

    Low energy efficiency and limitations of cooling temperatures in the ejector refrigeration systems (ERSs) are major obstacles for its widespread use. The application of binary or multicomponent fluids may prove to be one of the successful ways to increase the ERS performance by 30–50%. Zeotropic mixtures, which have unlimited solubility and evaporate at specified pressures and varying temperatures, are considered

  10. ARTI Refrigerant Database

    NASA Astrophysics Data System (ADS)

    Cain, J. M.

    1993-04-01

    The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate the phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in the 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 including 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.

  11. ARTI Refrigerant Database

    NASA Astrophysics Data System (ADS)

    Calm, J. M.

    1993-11-01

    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, though some may be added at a later date. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R134a, R-141b, R-142b, R-143a, R-152a, R-227ea, R-245ca, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyol 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. They are included to accelerate availability of the information and will be completed or replaced in future updates.

  12. ARTI Refrigerant Database

    SciTech Connect

    Cain, J.M. [Calm (James M.), Great Falls, VA (United States)

    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 including 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.

  13. Superfluid Stirling refrigerator with a counterflow regenerator

    SciTech Connect

    Brisson, J.G.; Swift, G.W.

    1992-01-01

    The superfluid Stirling refrigerator (SSR) uses a [sup 3]He-[sup 4]He liquid mixture as a working fluid. It operates at temperatures below 2 K where the [sup 4]He component of the working fluid is superfluid. The [sup 3]He component of the working fluid, to first approximation, behaves thermodynamically like an ideal gas in the inert background of superfluid [sup 4]He. Using pistons equipped with a superleak bypass, it is possible to expand and compress the [sup 3]He solute gas.'' The SSR is a Stirling machine equipped with these superleaked'' pistons to take advantage of the properties of the [sup 3]He solute to cool below 1 K. The proof of principle was shown by Kotsubo and Swift in 1990. There are three other techniques for cooling below 1 K: (1) the [sup 3]He-[sup 4]He dilution refrigerator which utilizes the endothermic heat of mixing of [sup 3]He into [sup 4]He to reach temperatures below 0.010 K; (2) the evaporation of [sup 3]He which can reach temperatures of 0.3 K; and, (3) adiabatic demagnetization of a paramagnetic salt. There are several advantages of the SSR over each of the other techniques. The power consumption of a dilution refrigerator is typically on the order of kilowatts; whereas, the SSR consumes hundreds of watts. The SSR has the potential to cool below 0.3 K and out-perform the evaporative [sup 3]He refrigerator. Adiabatic demagnetization often requires magnetic shielding between the refrigerator and the object to be cooled; obviously, the SSR requires no such shielding. There is an interest in developing subkelvin cryocoolers for satellite-borne X-ray and infrared detectors. In space applications, the power consumption of an SSR can be reduced to tens of watts. This coupled with the SSR's insensitivity to a zero G environment makes it an attractive option to cool detectors in space.

  14. Waste Heat Recovery from Refrigeration

    E-print Network

    Jackson, H. Z.

    1982-01-01

    heat recovery from refrigeration machines is a concept which has great potential for implementation in many businesses. If a parallel requirement for refrigeration and hot water exists, the installation of a system to provide hot water as a by...

  15. Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler

    NASA Astrophysics Data System (ADS)

    Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

    2014-01-01

    A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models.

  16. The Effect of Modified Atmosphere Packaging and Addition of Rosemary Extract, Sodium Acetate and Calcium Lactate Mixture on the Quality of Pre-cooked Hamburger Patties during Refrigerated Storage

    PubMed Central

    Muhlisin; Kang, Sun Moon; Choi, Won Hee; Lee, Keun Taik; Cheong, Sung Hee; Lee, Sung Ki

    2013-01-01

    The effect of modified atmosphere packaging (MAP; 30% CO2+70% N2 or 100% N2) and an additive mixture (500 ppm rosemary extract, 3,000 ppm sodium acetate and 1,500 ppm calcium lactate) on the quality of pre-cooked hamburger patties during storage at 5°C for 14 d was evaluated. The addition of the additive mixture reduced aerobic and anaerobic bacteria counts in both 30% CO2-MAP (30% CO2+70% N2) and 100% N2-MAP (p<0.05). The 30% CO2-MAP was more effective to suppress the microbial growth than 100% N2-MAP, moreover the 30% CO2-MAP combined with additive mixture resulted in the lowest bacterial counts. The hamburger patties with additive mixture showed lower CIE L* and CIE a*, and higher CIE b* than those with no additive mixture. The 30% CO2-MAP tended to decrease the TBARS during storage regardless of the addition of additives. The use of 30% CO2-MAP in combination with additives mixture was effective for maintaining the quality and extending the shelf-life of pre-cooked hamburger patties. PMID:25049716

  17. Evaluation of the Next Generation HFC Blowing Agents in Rigid Polyurethane Foams

    Microsoft Academic Search

    J. Wu; A. Albouy; D. Mouton

    1999-01-01

    The development of a third generation HFC blowing agent has achieved significant progress in the past few years. Several candidates have been identified as promising substitutes for HCFC-141b in foam applications.Elf Atochem has striven to provide alternatives after HCFC-141b phases out in foam applications. This paper summarizes our recent research activities in HFCs in rigid polyurethane foam applications. It includes

  18. Synchronized DMT for multipoint-to-point communications on HFC networks

    Microsoft Academic Search

    Krista S. Jacobsen; J. A. C. Bingham; J. M. Cioffi

    1995-01-01

    This paper presents a method for synchronizing a large number of discrete-multitone-based modems for multipoint-to-point communications on hybrid fiber-coax (HFC) networks. Each newly-installed remote unit is first loop-timed to the central modem master clock. Ranging is then performed to determine the sample delay required to align at the central unit receiver the symbols transmitted by the remote with those transmitted

  19. Vapor-Phase Helmholtz Equation for HFC227ea from Speed-of-Sound Measurements

    Microsoft Academic Search

    G. Benedetto; R. M. Gavioso; R. Spagnolo; M. Grigiante; G. Scalabrin

    2001-01-01

    This work presents measurements of the speed-of-sound in the vapor phase of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea). The measurements were obtained in a stainless-steel spherical resonator with a volume of ~900 cm3 at temperatures between 260 and 380 K and at pressures up to 500 kPa. Ideal-gas heat capacities and acoustic virial coefficients are directly produced from the data. A Helmholtz equation of

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

    SciTech Connect

    Shrestha, Som S [ORNL] [ORNL; Sharma, Vishaldeep [ORNL] [ORNL; Abdelaziz, Omar [ORNL] [ORNL

    2014-01-01

    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 and 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.

  1. Parametric amplifier with thermoelectric refrigeration

    Microsoft Academic Search

    M. Uenohara; R. Wolfe

    1961-01-01

    The noise figure of a variable-capacitance parametric amplifier can be greatly improved by refrigerating the diode. A thermoelectric refrigerator can be used for this purpose without losing the advantage of system simplicity. A two-stage thermoelectric refrigerator has been built into a 6-Gc parametric amplifier. With no load this refrigerator has produced a temperature difference of 101°C below room temperature. In

  2. Adsorption Refrigeration System

    SciTech Connect

    Wang, Kai [ORNL; Vineyard, Edward Allan [ORNL

    2011-01-01

    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 drawbacks 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.

  3. ARTI Refrigerant Database

    SciTech Connect

    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 refrigerant circuits. A computerized version is available that includes retrieval software.

  4. Saturated Liquid Densities of HCFC123, HFC134a, CFC11 and CFC12

    NASA Astrophysics Data System (ADS)

    Fukushima, Masato

    The saturated liquid densities of two environmentally acceptable hydrogen-containing halocarbons (HCFC123 and HFC134a) and two fully halogenated chlorofluorocarbons (CFCl1 and CFC12) were determined experimentally. The measurement has been conducted by the method using pyrex glass floats. Eleven saturated liquid densities were obtained in the range of temperature from 281 to 352 K for HCFC123. Seven saturated liquid densities were obtained in the range of temperature from 244 to 292 K for HFC134a. Eleven saturated liquid densities were obtained in the range of temperature from 285 to 361 K for CFC11. And ten saturated liquid densities were obtained in the range of temperature from 237 to 297 K for CFC12. The uncertainties of temperature and density are less than ±20 mK and ±3 kg/m3, respectively. On the basis of these results, the saturated liquid density correlations were developed for four halocarbons. The satuated liquid densities for HCFC123 are close to those for CFC11. And the saturated liquid densities for HFC134a are smaller than those for CFC12.

  5. Measurements of the PVT Properties of HCFC123 and HFC134a

    NASA Astrophysics Data System (ADS)

    Fukushima, Masato; Watanabe, Naohiro; Kamimura, Toru

    The vapor pressure and PVT properties in a superheated vapor and compressed liquid phase region of two environmentally acceptable hydrogen-containing halocarbons (HCFC123 and HFC134a) were determined experimentally. The measurements of vapor pressure and PVT properties were made using constant-volume method. Sixty-five vapor pressure points were obtained in the range of temperature of 314 K to critical temperature for HCFC123, and forty-one vapor pressure points were obtained in the range of temperature of 262K to critical temperature for HFC134a. Fifty-nine PVT data points were obtained in the range of temperature 352K to 484K, of pressure 0.5 to 5.2MPa and of density 29 to 1030 kg/m3. And sixty-three PVT data points, were obtained in the range of temperature 294K to 424K, of pressure 0.6 to 5.7MPa and of density 24 to 1101kg/m3. On the basis of these results, the critical pressure was determined to be 3.672MPa for HCFC123, and it was determined to be 4.055MPa for HFC134a. In addition, the equation of state and vapor pressure correlation were developed.

  6. Compressor calorimeter performance of refrigerant blends: Comparative methods and results for a refrigerator/freezer application

    SciTech Connect

    Rice, C K; Sand, J R

    1993-01-01

    A protocol was developed to define calorimeter operating pressures for nonazeotropic refrigerant mixtures (NARMs) which corresponded with the saturated evaporator and condenser temperatures commonly used for pure refrigerants. Compressor calorimeter results were obtained using this equivalent-mean-temperature (EMT) approach and a generally applied Association of Home Appliance Manufacturers (AHAM) procedure at conditions characteristic of a domestic refrigerator-freezer application. Tests with R-12 and two NARMs indicate that compressor volumetric and isentropic efficiencies are nearly the same for refrigerants with similar capacities and pressure ratios. The liquid-line temperature conditions specified in the AHAM calorimeter rating procedure for refrigerator-freezer compressors were found to preferentially derate NARM performance relative to R-12. Conversion of calorimeter data taken with a fixed liquid-line temperature to a uniform minimal level of condenser subcooling is recommended as a fairer procedure when NARMs are involved. Compressor energy-efficiency-ratio (EER) and capacity data measured as a result of the EMT approach were compared to system performance calculated using an equivalent-heat-exchanger-loading (EHXL) protocol based on a Lorenz-Meutzner (L-M) refrigerator-freezer modeling program. The EHXL protocol was used to transform the calorimeter results into a more relevant representation of potential L-M cycle performance. The EMT method used to set up the calorimeter tests and the AHAM liquid-line conditions combined to significantly understate the cycle potential of NARMs relative to that predicted at the more appropriate EHXL conditions. Compressor conditions representative of larger heat exchanger sizes were also found to give a smaller L-M cycle advantage relative to R-12.

  7. Design optimization of thermoacoustic refrigerators

    Microsoft Academic Search

    Martin Wetzel; Cila Herman

    1997-01-01

    Thermoacoustic refrigeration was developed during the past two decades as anew, environmentally safe refrigeration technology. The operation of thermoacoustic refrigerators employs acoustic power to pump heat. Nowadays, as commercial applications are sought, it is important to be able to obtain fast and simple engineering estimates for the design and optimization of prototypes. This paper provides such estimates by implementing the

  8. MOBILE AIR CONDITIONER REFRIGERANT EVALUATION

    EPA Science Inventory

    The paper discusses an evaluation of refrigerant from mobile air conditioners. The data gathered indicate that CFC-l2 refrigerant does not degrade significantly with use. Furthermore, while small amounts of contaminant are removed with the refrigerant during servicing, most of th...

  9. Solar-Powered Refrigeration System

    Microsoft Academic Search

    Michael K. Ewert; David J. Bergeron III

    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

  10. Combined thermionic-thermoelectric refrigerator

    Microsoft Academic Search

    X. C. Xuan

    2002-01-01

    A combined thermionic-thermoelectric refrigerator is proposed. The passive metal conductor in a vacuum thermionic refrigerator is replaced by an active p-type thermoelectric element, so that the Peltier cooling power can be exploited. Complete analytic formulas of performances are derived for the two types of thermionic refrigerators at both maximum cooling power density and optimum coefficient of performance. In employing the

  11. 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.

  12. HFC-152a and HFC-134a emission estimates and characterization of CFCs, CFC replacements, and other halogenated solvents measured during the 2008 ARCTAS campaign (CARB phase) over the South Coast Air Basin of California

    NASA Astrophysics Data System (ADS)

    Barletta, B.; Nissenson, P.; Meinardi, S.; Dabdub, D.; Sherwood Rowland, F.; Vancuren, R. A.; Pederson, J.; Diskin, G. S.; Blake, D. R.

    2011-03-01

    This work presents results from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Whole air samples were obtained on board research flights that flew over California during June 2008 and analyzed for selected volatile organic compounds, including several halogenated species. Samples collected over the South Coast Air Basin of California (SoCAB), which includes much of Los Angeles (LA) County, were compared with samples from inflow air masses over the Pacific Ocean. The levels of many halocarbon species were enhanced significantly over the SoCAB, including compounds regulated by the Montreal Protocol and subsequent amendments. Emissions estimates of HFC-152a (1,1-difluoroethane, CH3CHF2; 0.82 ± 0.11 Gg) and HFC-134a (1,1,1,2-tetrafluoroethane, CH2FCF3; 1.16 ± 0.22 Gg) in LA County for 2008 were obtained using the observed HFC:carbon monoxide (CO) enhancement ratio. Emission rates also were calculated for the SoCAB (1.60 ± 0.22 Gg yr-1 for HFC-152a and 2.12 ± 0.28 Gg yr-1 for HFC-134a) and then extrapolated to the United States (32 ± 4 Gg yr-1 for HFC-152a and 43 ± 6 Gg yr-1 for HFC-134a) using population data. In addition, emission rates of the two HFCs in LA County and SoCAB were calculated by a second method that utilizes air quality modeling. Emissions estimates obtained using both methods differ by less than 25% for the LA County and less than 45% for the SoCAB.

  13. Australian HFC, PFC and SF6 emissions: atmospheric verification

    NASA Astrophysics Data System (ADS)

    Fraser, P.; Dunse, B.; Krummel, P. B.; Steele, P.; Manning, A. J.

    2011-12-01

    The synthetic greenhouse gases (GHGs: hydrofluorocarbons - HFCs, perfluorocarbons - PFCs, and sulfur hexafluoride - SF6), emitted largely by the refrigeration, aluminium and electricity distribution industries respectively, are currently responsible for less than 2% of Australia's net long-lived GHG emissions (DCCEE, 2011). Nevertheless, they have attracted the attention of policymakers because (1) if their growth in concentrations and emissions continues unabated, particularly HFCs - currently growing at 10% per year - then they could be responsible globally (and in Australia) for more than 10% of the radiative forcing due to long-lived GHGs by 2050 (Velders et al., 2009); and (2) they provide the opportunity for a very cost-effective GHG mitigation strategy, because emissions can be reduced significantly through better engineering to minimize emissions, through a ban on dispersive uses (as solvents for example) and through the use of low GWP (Global Warming Potential) alternatives (for example hydrofluoroethers - HFEs). CSIRO, through its involvement in the AGAGE global program of monitoring non-carbon dioxide GHGs (Prinn et al., 2000), has been making high precision in situ measurements (12 per day) of HFCs, PFCs and SF6 at Cape Grim, Tasmania, since 2004, using a gas chromatograph-mass spectrometer detector (GC-MSD) fitted with a custom-built cryo-focussing unit (Medusa: Miller et al., 2008). The resultant data have been used to derive Australian emissions by inverse modelling (NAME, TAPM) and interspecies correlation (ISC). The overall agreement between so-called bottom-up estimates of Australian emissions, as reported to the UNFCCC (United Nations Framework Convention on Climate Change), and top-down estimates from atmospheric observations, using NAME, TAPM and ISC, is encouraging. Australian UNFCCC reported emissions (DCCEE, 2011) generally agree to within of 10% of emissions calculated from Cape Grim data, scaled on a population basis, with some notable exceptions. References DCCEE (2011), Australian National Greenhouse Accounts, National Inventory Report 2009, Volume 1, Australian Government Department of Climate Change and Energy Efficiency, 284 pp, April 2011. Miller, B., R. Weiss, P. Salameh, T. Tanhua, B. Greally, J. Muhle & P. Simmonds, Medusa: a sample pre-concentration and GC-MS detector system for in situ measurements of atmospheric trace halocarbons, hydrocarbons and sulphur compounds, Anal. Chem., 80 (5), 1536-1545, 2008. Prinn, R., R. Weiss, P. Fraser, P. Simmonds, D. Cunnold, F. Alyea, S. O'Doherty, P. Salameh, B. Miller, J. Huang, R. Wang, D. Hartley, C. Harth, P. Steele, G. Sturrock, P. Midgley & A. McCulloch, A history of chemically and radiatively important gases in air deduced from ALE/GAGE/AGAGE, Journal of Geophysical Research - Atmospheres, 105 (D14): 17751-17792, 2000.

  14. Step piston pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Zhu, Shaowei

    2014-11-01

    In this paper, a numerical simulation is done for a step piston pulse tube refrigerator. The step piston pulse tube refrigerator is a modification of an inertance tube pulse tube refrigerator, which has a step piston compressor. The step piston in a step cylinder forms a compression space which is connected to the after cooler and an expansion space which is connected to the buffer. Numerical simulation shows that it is more effective at higher refrigeration temperature. It also shows there is an optimum swept volume ratio of the expansion space over the compression space, and an optimum diameter and length of the inertance tube for a given refrigerator.

  15. Optimize refrigeration design

    SciTech Connect

    Baggio, J.L.

    1984-06-01

    Design of a propane refrigeration system using an economizer can be determined quickly by using a nomograph. Usually selection of economizer operating conditions and resulting requirements for compression are based on time consuming iterative calculations. These can be avoided and optimum operating conditions set with comparative ease using the nomograph. A simplified refrigeration system involves evaporation of propane refrigerant at low pressure in the evaporator where it chills process fluid. Vapor is then taken from the low pressure suction drum and compressed to a pressure high enough to be condensed at ambient temperature by air or water. Condensed refrigerant from the accumulator is then throttled to evaporator pressure and a new cycle started. All these phases can be represented on a P-H diagram. The quantity of vapor associated with liquid flashing across the throttle valve must be kept at a minimum since it does not add to evaporator heat exchange. Operation at high propane condensation temperatures (for example, condensed propane at 120/sup 0/F) and/or severe process fluid chilling temperatures (low pressure propane at - 35/sup 0/F) defeats this objective. When combined, these conditions lead to high compression power.

  16. 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.

  17. Thermoacoustic engines and refrigerators

    SciTech Connect

    Swift, G.W. [Los Alamos National Lab., NM (United States)

    1995-07-01

    We ordinarily think of a sound wave in a gas as consisting of coupled pressure and displacement oscillations. However, temperature oscillations always accompany the pressure changes. The combination of all these oscillations, and their interaction with solid boundaries, produces a rich variety of `thermoacoustic` effects. Although these effects as they occur in every-day life are too small to be noticed, one can harness extremely loud sound waves in acoustically sealed chambers to produce powerful heat engines, heat pumps and refrigerators. Whereas typical engines and refrigerators have crankshaft-coupled pistons or rotating turbines, thermoacoustic engines and refrigerators have at most a single flexing moving part (as in a loudspeaker) with no sliding seals. Thermoacoustic devices may be of practical use where simplicity, reliability or low cost is more important than the highest efficiency (although one cannot say much more about their cost-competitiveness at this early stage). This paper discusses the fundamentals of thermoacoustic engines and refrigerators, research in this field, and their commercial development. 16 refs., 5 figs.

  18. Design of thermoacoustic refrigerators

    Microsoft Academic Search

    M. E. H. Tijani; J. C. H. Zeegers

    2002-01-01

    In this paper the design of thermoacoustic refrigerators, using the linear thermoacoustic theory, is described. Due to the large number of parameters, a choice of some parameters along with dimensionless independent variables will be introduced. The design strategy described in this paper is a guide for the design and development of thermoacoustic coolers. The optimization of the different parts of

  19. Thermoacoustic Refrigeration Device

    Microsoft Academic Search

    E. Qing; Feng Wu; Duanyong Li; Fangzhong Guo

    2009-01-01

    A thermoacoustic refrigeration device (TAR) includes an acoustic wave generation device arranged directed to the channel of a hollow tube, and a regenerator provided at a predetermined position in the channel of the tube. A temperature gradient is obtained across the regenerator by an acoustic wave emitted from the acoustic wave generation device. Therefore, a TAR realizing a gas Stirling

  20. Education in Helium Refrigeration

    SciTech Connect

    Gistau Baguer, G. M. [38330, Biviers (France)

    2004-06-23

    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.

  1. Improved cryogenic refrigeration system

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1967-01-01

    Two-position shuttle valve simplifies valving arrangement and crank-shaft configuration in gas-balancing and Stirling-cycle refrigeration systems used to produce temperatures below 173 degrees K. It connects the displacer and regenerator alternately to the supply line or the return line of the compressor, and establishes constant pressure on the drive piston.

  2. Seawater refrigerating system failure

    Microsoft Academic Search

    S. Simison; F. Gomez; A. Steckinger; S. R. de Sanchez

    1995-01-01

    The cause of failures of copper-nickel pipes in the seawater refrigerating systems of two ships was analyzed. Failure is attributed to poor design of the weldments aggravated by seawater contamination. Welds placed too close to each other promoted sensitization of the material. The alloy had been heated to the precipitation range of an iron-rich second phase, and a pronounced root

  3. Refrigeration and air conditioning

    Microsoft Academic Search

    B. J. Brinkworth

    1977-01-01

    Requirements for cooling are related to the need to be able to maintain foodstuffs in good condition with the aid of refrigeration and the desirability to provide a comfortable indoor environment by air conditioning. The representation of the desired conditions in a room by a point on a psychrometric chart is considered together with processes of sensible cooling, cooling and

  4. One of the limitations of using refrigerant mixtures to achieve capacity modulation is that the range of capacity control and the temperature glide are both functions of the difference

    E-print Network

    Oak Ridge National Laboratory

    present risks to safety due to flammability. However, since this mixture had the potential for matching the sensors and gives their locations. DATA ACQUISITION SYSTEM The data acquisition system consisted-speed programming language. Voltage data signals were read from the instrumentation by the digital voltmeter

  5. Non-inert refrigerant study for automotive applications. Final report, March--December 1990

    SciTech Connect

    Dieckmann, J.T.; Bentley, J.; Varone, A.

    1991-11-01

    Alternatives to CFC-12 for automobile air conditioning were examined. The list of candidate fluids included flammable as well as non-flammable substances. HFC-134a was taken as the baseline alternative given current industry plans to convert automobile air conditioning systems to this fluid over the next several years. Three flammable (non-inert) altemative refrigerants -- BFC-152a, HC-290 (propane) and HC-270 (cyclopropane) were identified. Air conditioning cycle efficiency, ozone depletion potential, and global warming impacts of these three fluids and HFC-134a were compared, with the three non-inert fluids all having higher COP and lower global warming impact. The ozone depletion potential of each of these fluids is zero. The fire safety implications of the flammable alternatives being used in otherwise conventional automobile air conditioning systems were examined in preliminary fashion. The results, which are subject to more extensive verification indicate that the additional passenger compartment fire risk would be very small, while the incidence of engine compartment fires would increase modestly. The engine compartment fire hazard could be minimized by modest design changes to reduce the occurrence of ignition sources and condenser punctures in front end collisions.

  6. Toxicokinetics of 1,1,1,2-tetrafluoroethane (HFC-134a) in male volunteers after experimental exposure.

    PubMed

    Gunnare, Sara; Ernstgård, Lena; Sjögren, Bengt; Johanson, Gunnar

    2006-11-01

    The aim of this study was to determine the uptake and disposition of inhaled 1,1,1,2-tetrafluoroethane (HFC-134a) in humans. Ten male volunteers were exposed to 500 ppm HFC-134a (2 h, 50 W exercise). The HFC-134a levels were monitored in blood, exhaled air and urine up to 19 h post-exposure. The concentration in blood increased rapidly, reaching a plateau of 9.4+/-1.9 microM (mean+/-S.D.) within 30 min, followed by a fast post-exposure decrease. HFC-134a in expired air decreased rapidly as well and in parallel with that in blood. The post-exposure urinary excretion was 0.002% of the inhaled amount, and the half-time was 58 min (pooled data). A physiologically based toxicokinetic (PBTK) model was developed for further analysis. Experimental and simulated time courses in blood and exhaled air agreed well in all 10 subjects. Further, the late decay in blood was consistent with a wash-out of HFC-134a from fat tissues, with a half-time of 114+/-21 min. The simulated relative uptake during exposure was 3.7+/-0.5%. No remarkable findings were observed in the electrocardiographic recordings. Fibrinogen in plasma increased 1 day after exposure, whereas no effects on C-reactive protein, serum amyloid A protein, D-dimer or uric acid were seen. Further studies are needed to investigate the possible inflammatory response. PMID:17030466

  7. Optimal performance of a thermoelectric refrigerator

    Microsoft Academic Search

    Jincan Chen; Zijun Yan

    1994-01-01

    The optimal performance of a thermoelectric device used as a refrigerator is discussed by using the rate of refrigeration and the coefficient of performance of the refrigerator under the influence of three main irreversibilities which are heat conduction, heat leak, and Joule heat. The coefficient of performance and the operating current of the refrigerator at the maximum rate of refrigeration

  8. Determination of a vapor compression refrigeration system refrigerant charge

    Microsoft Academic Search

    Chun-Xin Yang; Chao-Bin Dang

    1995-01-01

    A physical model is established in this paper to describe the heat transfer and two phase flow of a refrigerant in the evaporator\\u000a and condenser of a vapor compression refrigeration system. The model is then used to determine the refrigerant charge in vapor\\u000a compression units. The model is used for a sensitivity analysis to determine the effect that varing design

  9. 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.

  10. 40 CFR Appendix C to Subpart B of... - SAE J2788 Standard for Recovery/Recycle and Recovery/Recycle/Recharging Equipment for HFC-134a...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...equipment requirements for the recovery/recycling of HFC-134a that has been directly...air-conditioning systems and recovery/recycling and system recharging of recycled...performance requirements for recovery and recycling of HFC-134a that has been...

  11. 40 CFR Appendix C to Subpart B of... - SAE J2788 Standard for Recovery/Recycle and Recovery/Recycle/Recharging Equipment for HFC-134a...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...equipment requirements for the recovery/recycling of HFC-134a that has been directly...air-conditioning systems and recovery/recycling and system recharging of recycled...performance requirements for recovery and recycling of HFC-134a that has been...

  12. 40 CFR Appendix C to Subpart B of... - SAE J2788 Standard for Recovery/Recycle and Recovery/Recycle/Recharging Equipment for HFC-134a...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...equipment requirements for the recovery/recycling of HFC-134a that has been directly...air-conditioning systems and recovery/recycling and system recharging of recycled...performance requirements for recovery and recycling of HFC-134a that has been...

  13. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A. (Los Alamos, NM)

    1992-01-01

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

  14. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

    This invention is comprised of a compact acoustic refrigeration system that actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment.

  15. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, G.W.; Kotsubo, V.Y.

    1992-12-22

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of [sup 3]He in a single phase [sup 3]He-[sup 4]He solution. The [sup 3]He in superfluid [sup 4]He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid [sup 3]He at an initial concentration in superfluid [sup 4]He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of [sup 4]He while restricting passage of [sup 3]He. The [sup 3]He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K. 12 figs.

  16. Oxygen chemisorption cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (inventor)

    1987-01-01

    The present invention relates to a chemisorption compressor cryogenic refrigerator which employs oxygen to provide cooling at 60 to 100 K. The invention includes dual vessels containing an oxygen absorbent material, alternately heated and cooled to provide a continuous flow of high pressure oxygen, multiple heat exchangers for precooling the oxygen, a Joule-Thomson expansion valve system for expanding the oxygen to partially liquefy it and a liquid oxygen pressure vessel. The primary novelty is that, while it was believed that once oxygen combined with an element or compound the reaction could not reverse to release gaseous oxygen, in this case oxygen will indeed react in a reversible fashion with certain materials and will do so at temperatures and pressures which make it practical for incorporation into a cryogenic refrigeration system.

  17. Trifluoroacetate in the environment. Evidence for sources other than HFC/HCFCs

    SciTech Connect

    Jordan, A.; Frank, H. [Univ. of Bayreuth (Germany)] [Univ. of Bayreuth (Germany)

    1999-02-15

    The partly halogenated C{sub 2}-hydro(chloro)fluorocarbons (HFC, HCFC) 1,1,1-trifluoro-2,2-dichloroethane (HCFC-123), 1,1,1,2-tetrafluoro-2-chloroethane (HCFC-124), and 1,1,1,2-tetrafluoroethane (HFC-134a) are CFC substitutes found at increasing levels in the atmosphere. Trifluoroacetate (TFA) is an atmospheric degradation product of these compounds and due to its persistence its potential accumulation in some aquatic ecosystems is a matter of environmental concern. The present study was undertaken to determine the present-days base level of environmental TFA and whether model calculations are in line with the actual data. Average levels of about 120 ng L{sup {minus}1} as predicted for the year 2010 are found in rain in Germany already now, slightly higher than in rain collected in Switzerland or Nevada. In the major rivers in Germany, TFA is present at average concentrations of 140 ng L{sup {minus}1}. In air, levels of 45--60 pg m{sup {minus}3} have been found in Central Europe. Between March 1995 and September 1996, a period of substantial increase in atmospheric HFC-134a mixing ratio, the TFA concentrations in air and precipitation did not significantly increase. TFA is absent in old groundwater samples, and in river water from remote locations, concentrations are low. These data suggest that the total TFA in both compartments exceeds the formation potential of currently known sources, that TFA in atmosphere and rain is regionally associated with industrial or population density, and that other unresolved sources must contribute to the present concentrations.

  18. Atmospheric degradation mechanisms of hydrogen containing chlorofluorocarbons (HCFC) and fluorocarbons (HFC)

    NASA Technical Reports Server (NTRS)

    Zellner, Reinhard

    1990-01-01

    The current knowledge of atmospheric degradation of hydrogen containing chlorofluorocarbons (HCFC 22 (CHClF2), HCFC 123 (CHCl2CF3), HCFC 124 (CHClFCF3), HCFC 141b (CFCl2CH3), HCFC 142b (CF2ClCH3)) and fluorocarbons (HFC 125 (CHF2CF3), HFC 134a (CH2FCF3), HFC 152a (CHF2CH3)) is assessed. Except for the initiation reaction by OH radicals, there are virtually no experimental data available concerning the subsequent oxidative breakdown of these molecules. However, from an analogy to the degradation mechanisms of simple alkanes, some useful guidelines as to the expected intermediates and final products can be derived. A noteable exception from this analogy, however, appears for the oxi-radicals. Here, halogen substitution induces new reaction types (C-Cl and C-C bond ruptures) which are unknown to the unsubstituted analogues and which modify the nature of the expected carbonyl products. Based on an evaluation of these processes using estimated bond strength data, the following simplified rules with regards to the chlorine content of the HCFC's may be deduced: (1) HCFC's containing one chlorine atom such as 22 and 142b seem to release their chlorine content essentially instantaneous with the initial attack on the parent by OH radicals, and for HCFC 124, such release is apparently prevented; (2) HCFC's such as 123 and 141b with two chlorine atoms are expected to release only one of these instantaneously; and the second chlorine atom may be stored in potentially long-lived carbonyl compounds such as CF3CClO or CClFO.

  19. First remote sensing observations of trifluoromethane (HFC-23) in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Harrison, Jeremy J.; Boone, Christopher D.; Brown, Alexander T.; Allen, Nicholas D. C.; Toon, Geoffrey C.; Bernath, Peter F.

    2012-03-01

    This work reports the first remote sensing measurements of atmospheric HFC-23 (CHF3) using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and the Jet Propulsion Laboratory Mark IV (MkIV) balloon interferometer. A total of 8809 ACE occultations measured between 2004 and 2010 have been processed, along with 24 MkIV occultations measured between 1989 and 2007. ACE data (yearly averages over the 10-25 km altitude range) in the tropics/subtropics (40°S-40°N) reveal a trend of 4.0 ± 1.6% per year in the growth of HFC-23 for 2004-2009 (or 3.9 ± 1.2% per year for 2004-2010), slightly smaller than surface measurements from Cape Grim air archive samples over the same time period (4.7 ± 0.3% per year). The northern midlatitude and high-latitude MkIV data (averaged over the 10-25 km altitude range) indicate a growth rate of 5.8 ± 0.3% per year over the period 1989-2007 (5.3 ± 0.4% per year for just the midlatitude data), similar to the Cape Grim surface trend of 5.7 ± 0.1% per year over the same period. The absolute HFC-23 volume mixing ratios measured by ACE and MkIV in the upper troposphere/lower stratosphere are in good agreement (<5% bias) with each other but are ˜30% larger than ground-based measurements. The source of this bias has not been definitively ascertained; however, spectroscopic errors are the most likely cause.

  20. Refrigeration and Food Safety

    MedlinePLUS

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... Food Safety / Refrigeration and Food Safety Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  1. Thermodynamic improvements for the space thermoacoustic refrigerator (STAR)

    NASA Astrophysics Data System (ADS)

    Susalla, Michael P.

    1988-06-01

    The objective of the STAR project is to test and space-qualify a new continuous cycle cryogenic refrigeration system for cooling of sensors and electronics which is based on the newly discovered thermoacoustic heat pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 Hz, and uses acoustic resonance to enhance the overall power density and efficiency. This thesis is concerned specifically with the design and testing of the thermodynamic element (or stack), which is responsible for the thermo-acoustic power conversion, and the testing of binary inert gas mixtures as working fluids. Using the refrigerator's coefficient of performance relative to the ideal Carnot coefficient of performance as a measure of efficiency, a 93 percent improvement over previous designs has been achieved.

  2. Thermoacoustic Refrigerator's Stack Optimization

    NASA Astrophysics Data System (ADS)

    El-Fawal, Mawahib Hassan; Mohd-Ghazali, Normah; Yaacob, Mohd. Shafik; Darus, Amer Nordin

    2010-06-01

    The standing wave thermoacoustic refrigerator, which uses sound generation to transfer heat, was developed rapidly during the past four decades. It was regarded as a new, promising and environmentally benign alternative to conventional compression vapor refrigerators, although it was not competitive regarding the coefficient of performance (COP) yet. Thus the aim of this paper is to enhance thermoacoustic refrigerator's stack performance through optimization. A computational optimization procedure of thermoacoustic stack design was fully developed. The procedure was designed to achieve optimal coefficient of performance based on most of the design and operating parameters. Cooling load and acoustic power governing equations were set assuming the linear thermoacoustic theory. Lagrange multipliers method was used as an optimization technique tool to solve the governing equations. Numerical analyses results of the developed design procedure are presented. The results showed that the stack design parameters are the most significant parameters for the optimal overall performance. The coefficient of performance obtained increases by about 48.8% from the published experimental optimization methods. The results are in good agreement with past established studies.

  3. Formation of fluorinated nonionic surfactant microemulsions in hydrofluorocarbon 134a (HFC 134a)

    Microsoft Academic Search

    Nilesh Patel; Maria Marlow; M. Jayne Lawrence

    2003-01-01

    A structurally related series of fluorinated nonionic oxyethylene glycol surfactants of the type CmF2m+1(CH2)nO[(CH2CH2O)pH], denoted Cm.nEp (where m=4, 6, or 7, m=1 or 2, and p=4 or 6) were synthesized and their surface behavior in aqueous solution was characterized. The ability of these surfactants to form water-in-hydrofluorocarbon (HFC) propellant 134a microemulsions suitable for use in the aerosolized delivery of water-soluble

  4. Analyzing of Thermoelectric Refrigerator Performance

    Microsoft Academic Search

    Suwit Jugsujinda; Athorn Vora-ud; Tosawat Seetawan

    2011-01-01

    The refrigeration system of thermoelectric refrigerator (TER; 25×25×35cm3) was fabricated by using a thermoelectric cooler (TEC; 4×4cm2) and applied electrical power of 40W. The TER has not cooling fan for the coldness circulates in the refrigerator. The temperature of TER was measured at ten points to check the cooling system. The current, differential temperature, time, and coefficient of performance (COP)

  5. 46 CFR 154.1720 - Indirect refrigeration.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Design and Operating Requirements § 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...

  6. 46 CFR 154.1720 - Indirect refrigeration.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Design and Operating Requirements § 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...

  7. 46 CFR 154.1720 - Indirect refrigeration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Design and Operating Requirements § 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...

  8. 49 CFR 173.174 - Refrigerating machines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Refrigerating machines. 173.174 Section 173.174 Transportation...Class 1 and Class 7 § 173.174 Refrigerating machines. A refrigerating machine assembled for shipment and containing 7 kg...

  9. 49 CFR 173.174 - Refrigerating machines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Refrigerating machines. 173.174 Section 173.174 Transportation...Class 1 and Class 7 § 173.174 Refrigerating machines. A refrigerating machine assembled for shipment and containing 7 kg...

  10. SiC coating toughened by HfC nanowires to protect C/C composites against oxidation

    NASA Astrophysics Data System (ADS)

    Zhang, Yulei; Ren, Jincui; Tian, Song; Li, Hejun; Hu, Zhixiong

    2014-08-01

    To prevent carbon/carbon (C/C) composites from oxidation at high temperature, a dense SiC coating toughened by HfC nanowires was prepared by a two-step technique of chemical vapor deposition (CVD) and pack cementation. The microstructure, mechanical properties and oxidation resistance of the coating were investigated. The HfC nanowires can effectively reduce the size of microcracks and avoid the formation of through-thickness microcracks in the SiC coating. Due to the toughening mechanisms including microcrack bridging by nanowire and nanowire pullout, the mechanical properties and oxidation resistance of the coating are improved.

  11. Condensation of refrigerants flowing inside smooth and corrugated tubes

    SciTech Connect

    Hinton, D.L. [Tennessee State Univ., Nashville, TN (United States); Conklin, J.C.; Vineyard, E.A. [Oak Ridge National Lab., TN (United States)

    1995-07-01

    Because heat exchanger thermal performance has a direct fluence on the overall cycle performance of vapor-compression refrigeration machinery,enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. We investigated R-22 and a nonazeotropic refrigerant mixture (NARM) of 75% R-143a and 25% R-124 (by mass) to study their thermal performance in a condenser made of conventional smooth tubes and another condenser made of corrugated, or spirally indented, tubes. We investigated the condensing heat transfer and pressure drop characteristics in an experimental test loop model of a domestic beat pump system employing a variable speed compressor. The refrigerant circulates inside the central tube and the water circulates in the annulus. At refrigerant mass fluxes of approximately 275--300 kg/m{sup 2}s, the measured irreversible pressure drop of the corrugated surface was 23% higher than that of the smooth surface for the R-22. At refrigerant mass fluxes of 350-370 kg/m{sup 2}s, the irreversible pressure drop of the corrugated surface was 36% higher than that of the smooth surface for the NARM. The average heat transfer coefficient for the corrugated surface for R-22 was roughly 40% higher than that for the smooth tube surface at refrigerant mass fluxes of 275--295 kg/m{sup 2}s. The average heat transfer coefficient for the corrugated surface for the NARM was typically 70% higher than that for the smooth tube surface at refrigerant mass fluxes of 340--385 kg/m{sup 2}s.

  12. Refrigerator-freezer energy testing with alternative refrigerants

    SciTech Connect

    Vineyard, E.A.; Sand, J.R.; Miller, W.A.

    1989-01-01

    As a result of the Montreal Protocol that limits the production of ozone-depleting refrigerants, manufacturers are searching for alternatives to replace the R12 that is presently used in residential refrigerator-freezers. Before an alternative can be selected, several issues must be resolved. Among these are energy impacts, system compatibility, cost, and availability. In an effort to determine the energy impacts of some of the alternatives, energy consumption tests were performed in accordance with section 8 of the Association of Home Appliance Manufacturers (AHAM) standard for household refrigerators and household freezers. The results are presented for an 18 cubic foot (0.51 cubic meter), top-mount refrigerator-freezer with a static condenser using the following refrigerants: R12, R500, R12/Dimethyl-ether (DME), R22/R142b, and R134a. Conclusions from the AHAM test are that R500 and R12 /DME have a reduced energy consumption relative to R12 when replaced in the test unit with no modifications to the refrigeration system. Run times were slightly lower than R12 for both refrigerants indicating a higher capacity. While the R134a and R22/R142b results were less promising refrigeration system, such as a different capillary tube or compressor, may improve their performance. 12 refs., 2 figs., 3 tabs.

  13. Natural refrigerants for refrigeration and air-conditioning systems

    Microsoft Academic Search

    S. B. Riffat; C. F. Afonso; A. C. Oliveira; D. A. Reay

    1997-01-01

    In the past, several natural working fluids were used in refrigeration and air-conditioning systems. However, the appearance of CFCs caused a drastic reduction in the utilisation of those fluids. Understanding of the environmental damage of CFCs focused attention on alternative refrigerants. From these, the ones that have minimum (or nil) environmental impact are natural ones. This paper presents a review

  14. JPL research to develop a He-3/He-4 dilution refrigerator for space applications

    NASA Astrophysics Data System (ADS)

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

    A research program to develop a He-3/He-4 solution refrigerator for space applications is underway. The results of the effort to use an electric field as a substitute for gravity to control the He-3/He-4 mixture interface that separates phases in terrestrial units are described. Further, experimental results obtained from an engineering model of a single-cycle dilution refrigerator with a mixing chamber capable of operating in a zero-gravity environment are described. Future research and development plans are outlined, in particular the need to test the operation of a single-cycle as well as a continuously operating dilution refrigerator in space.

  15. Binary and ternary blends of R-134a as alternative refrigerants to R-22

    Microsoft Academic Search

    A. Stegou-Sagia; M. Damanakis

    2000-01-01

    Refrigerant mixtures may be used to solve the ozone layer depletion problem as they offer the optimum combination of favorable technical performance with environmentally acceptable behavior. This work reports the thermodynamic properties and characteristics of the binary mixtures R-32\\/R-134a in compositions 20–80%, 30–70%, 40–60% by mass and of the ternary mixture R-407c: 23 wt% R-32 + 25 wt% R-125 +

  16. Near azeotropic mixture substitute for dichlorodifluoromethane

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1998-01-01

    A refrigerant and a process of formulating thereof that consists of a mixture of a first mole fraction of CH.sub.2 FCF.sub.3 and a second mole fraction of a component selected from the group consisting of a mixture of CHClFCF.sub.3 and CH.sub.3 CClF.sub.2 ; a mixture of CHF.sub.2 CH.sub.3 and CH.sub.3 CClF.sub.2 ; and a mixture of CHClFCF.sub.3, CH.sub.3 CClF.sub.2 and CHF.sub.2 CH.sub.3.

  17. MFTF-B refrigerator analysis

    SciTech Connect

    NONE

    1995-02-10

    The purpose of this analysis was to determine the applicability of the MFTF-B helium refrigerator to the requirements of the TPX Tokomak at Princeton. The TPX requires a high pressure stream of supercritical gas to all loads rather than the liquid helium loads that the refrigerator was originally designed to support.

  18. Thermoacoustic Refrigerator Design and Performance

    Microsoft Academic Search

    Thomas James Hofler

    1986-01-01

    The thermoacoustic theory of N. Rott is applied to a design for a thermoacoustic refrigerator having one moving part. Some general features and practical aspects of the design are discussed. A fully functional refrigerator has been constructed and its measured temperature and efficiency performance is presented. The lowest measured ratio of cold temperature to ambient temperature is 0.66 and the

  19. Semiconductor-based optical refrigerator

    DOEpatents

    Epstein, Richard I. (Santa Fe, NM); Edwards, Bradley C. (Nekoosa, WI); Sheik-Bahae, Mansoor (Albuquerque, NM)

    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.

  20. Regenerative Sorption Refrigerator

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    Two-stage sorption refrigerator achieves increased efficiency via regenerative-heating concept in which waste heat from praseodymium/cerium oxide (PCO) chemisorption compressor runs charcoal/krypton (C/Kr) sorption compressor. Waste heat from each PCO sorption compressor used to power surrounding C/Kr sorption compressor. Flows of heat in two compressor modules controlled by gas-gap thermal switches. Has no wearing moving parts other than extremely long life, room-temperature check valves operating about twice per hour. Virtually no measurable vibration, and has potential operating life of at least ten years.

  1. The refrigerator revolution

    SciTech Connect

    Ayres, E.; French, H.

    1996-09-01

    This article discusses how a simple, new technology threw the best-laid plans of the chemical and refrigerator industries into disarray-and provided a new perspective on how future environmental agreements can be reached. In recent years, a series of massive business mergers has mesmerized the industrial world. However in the early 1990s a German environmentalist, triggered global reprocussions in the wake of the mandate to phase out the use of ozone depleting substances. The economic and political background of this is explained in detail.

  2. Mechanism of the Enzymatic Synthesis of 4-(Hydroxymethyl)-2- furancarboxaldehyde-phosphate (4-HFC-P) from Glyceraldehyde-3-phosphate Catalyzed by 4-HFC-P Synthase.

    PubMed

    Wang, Yu; Jones, Michael K; Xu, Huimin; Ray, W Keith; White, Robert H

    2015-05-19

    A single enzyme, 4-(hydroxymethyl)-2-furancarboxaldehyde-phosphate synthase (MfnB), from the methanogen Methanocaldococcus jannaschii catalyzed at least 10 separate chemical reactions in converting two molecules of glyceraldehyde-3-P (GA-3-P) to 4-(hydroxymethyl)-2-furancarboxaldehyde-P (4-HFC-P), the first discrete intermediate in the biosynthetic pathway to the furan moiety of the coenzyme methanofuran. Here we describe the biochemical characterization of the recombinantly expressed MfnB to understand its catalytic mechanism. Site-directed mutagenesis showed that the strictly conserved residues (Asp25, Lys27, Lys85, and Asp151) around the active site are all essential for enzyme catalysis. Matrix-assisted laser desorption/ionization analysis of peptide fragments of MfnB incubated with GA-3-P followed by NaBH? reduction and trypsin digestion identified a peptide with a mass/charge ratio of 1668.8 m/z present only in the D25N, D151N, and K155R mutants, which is consistent with Lys27 having increased by a mass of 58 m/z, indicating that Lys27 forms a Schiff base with a methylglyoxal-like intermediate. In addition, incubation of MfnB with GA-3-P in the presence of deuterated water or incubation of MfnB with C-2 deuterated GA-3-P showed essentially no deuterium incorporated into the 4-HFC-P. Combined with structural analysis and molecular docking, we predict the potential binding sites for two GA-3P molecules in the active site. On the basis of our observations, a possible catalytic mechanism of MfnB is proposed in this study. A phosphate elimination reaction and a triose phosphate isomerase-like reaction occur at the GA-3-P binding site I and II, respectively, prior to the aldol condensation between the enzyme-bound enol form of methylglyoxal and dihydroxyacetone phosphate (DHAP), after which the catalytic cycle is completed by a cyclization and two dehydration reactions assisted by several general acids/bases at the same active site. PMID:25905665

  3. Atomic-Scale Thermoelectric Refrigerator

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chang; Liu, Yu-Shen

    2010-03-01

    We propose a thermoelectric cooling device based on an atomic-sized junction. Using first-principles approaches, we investigate the working conditions and the coefficient of performance (COP) of an atomic junction as an electronic refrigerator. Our research reveals that the absence of local heating and the suppression of the tunneling barrier by the bridging atoms are favorable for the operation of atomistic refrigerators. From the self-consistent DFT calculations, we show that the atomistic refrigerator may operate at temperatures below 100 K. This is a great improvement in comparison with the vacuum diode. We also investigate the impact of the phononic heat current on the capability of refrigeration in the nano-refrigerator. To minimize the adverse effects of the phononic heat current, we suggest creating a poor mechanical link between the nano-structured object and the electrodes while still allowing electrons to tunnel.

  4. Uniform temperature cooling power of the superfluid stirling refrigerator

    SciTech Connect

    Watanabe, A.; Brisson, J.G. [Massachusetts Inst. of Technology, Cambridge, MA (United States); Swift, G.W. [Los Alamos National Laboratory, NM (United States)

    1996-06-01

    Uniform temperature cooling power measurements of a superfluid Stirling refrigerator are presented for {sup 3}He-{sup 4}He molar concentrations of 5.9%, 17% and 36% and for temperatures between 0.37 K and 1.4 K. The results are compared to an ideal Fermi gas model and to a more general thermodynamic model. The Fermi model agrees well with the 5.9% concentration data; however, the more elaborate model is needed for higher concentration mixtures.

  5. First appearance and rapid growth of anthropogenic HFC-245fa (CHF2CH2CF3) in the atmosphere

    NASA Astrophysics Data System (ADS)

    Vollmer, Martin K.; Reimann, Stefan; Folini, Doris; Porter, Laurence W.; Steele, L. Paul

    2006-10-01

    We capture the first atmospheric appearance of HFC-245fa (CHF2CH2CF3), a new foam blowing agent. Our results from the high-altitude observatory at Jungfraujoch, Switzerland, show a rapid growth of this substance in the northern hemispheric troposphere from 0.28 ppt in July 2004 to 0.68 ppt at the end of 2005, which corresponds to an overall increase of >90% per year. By combining our observations with an atmospheric 3-box model we estimate a southern hemispheric trend for this trace gas which we compare to observations at southern hemisphere mid-latitudes. We also estimate a global HFC-245fa emissions increase from 2100-2400 tonnes in 2003 to 5100-5900 tonnes in 2005. Pollution episodes are relatively rare at Jungfraujoch compared to other hydrofluorocarbons thereby confirming the limited use of HFC-245fa in Europe. Back trajectory analysis reveals the largest potential European sources of HFC-245fa in northern Italy and northeastern Spain.

  6. Influence of lubricant oil on heat transfer performance of refrigerant flow boiling inside small diameter tubes. Part II: Correlations

    SciTech Connect

    Wei, Wenjian; Ding, Guoliang; Hu, Haitao [Refrigeration and Cryogenics Institute, Department of Power and Energy Engineering, Shanghai JiaoTong University, Shanghai 200030 (China); Wang, Kaijian [Fujitsu General Institute of Air-Conditioning Technology Limited, Kawasaki 213-8502 (Japan)

    2007-10-15

    The predictive ability of the available state-of-the-art heat transfer correlations of refrigerant-oil mixture is evaluated with the present experiment data of small tubes with inside diameter of 6.34 mm and 2.50 mm. Most of these correlations can be used to predict the heat transfer coefficient of 6.34 mm tube, but none of them can predict heat transfer coefficient of 2.50 mm tube satisfactorily. A new correlation of two-phase heat transfer multiplier with local properties of refrigerant-oil mixture is developed. This correlation approaches the actual physical mechanism of flow boiling heat transfer of refrigerant-oil mixture and can reflect the actual co-existing conditions of refrigerant and lubricant oil. More than 90% of the experiment data of both test tubes have less than {+-}20% deviation from the prediction values of the new correlations. (author)

  7. Docmentation of newly developed methods to assess material compatibility in refrigeration and air-conditioning applications. Final report, 1 October 1993--31 August 1994

    Microsoft Academic Search

    Hawley

    1994-01-01

    This document summarizes the experimental methods used during the materials compatibility and lubricants research program (MCLR). The MCLR program was jointly sponsored by the U.S. Department of Energy and the air-conditioning and refrigeration industry. The individual projects were managed by the Air-Conditioning and Refrigeration Technology Institute. The projects presented in this report are: Chemical and Thermal Stability of Refrigerant\\/Lubricant Mixtures

  8. Finite-time optimum refrigeration cycles

    Microsoft Academic Search

    Mohand A. Ait-Alia

    1995-01-01

    A class of conceptual optimum refrigeration cycles is considered with a fixed overall heat conductance and a specified refrigerant operating temperature range to bound the optimization problems. These cycles deal with maximum refrigeration power, maximum refrigeration load, and maximum heat rejection load for the case of a heat pump. The resulting one degree of freedom problems are solved with a

  9. Thermoelectric refrigerator having improved temperature stabilization means

    Microsoft Academic Search

    Falco

    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

  10. Using Acid Number as a Leading Indicator of Refrigeration and Air Conditioning System Performance

    SciTech Connect

    Dennis Cartlidge; Hans Schellhase

    2003-07-31

    This report summarizes a literature review to assess the acidity characteristics of the older mineral oil and newer polyolester (POE) refrigeration systems as well as to evaluate acid measuring techniques used in other non-aqueous systems which may be applicable for refrigeration systems. Failure in the older chlorofluorocarbon/hydrochlorofluorocarbon (CFC/HCFC) / mineral oil systems was primarily due to thermal degradation of the refrigerant which resulted in the formation of hydrochloric and hydrofluoric acids. These are strong mineral acids, which can, over time, severely corrode the system metals and lead to the formation of copper plating on iron surfaces. The oil lubricants used in the older systems were relatively stable and were not prone to hydrolytic degradation due to the low solubility of water in oil. The refrigerants in the newer hydrofluorocarbon (HFC)/POE systems are much more thermally stable than the older CFC/HCFC refrigerants and mineral acid formation is negligible. However, acidity is produced in the new systems by hydrolytic decomposition of the POE lubricants with water to produce the parent organic acids and alcohols used to prepare the POE. The individual acids can therefore vary but they are generally C5 to C9 carboxylic acids. Organic acids are much weaker and far less corrosive to metals than the mineral acids from the older systems but they can, over long time periods, react with metals to form carboxylic metal salts. The salts tend to accumulate in narrow areas such as capillary tubes, particularly if residual hydrocarbon processing chemicals are present in the system, which can lead to plugging. The rate of acid production from POEs varies on a number of factors including chemical structure, moisture levels, temperature, acid concentration and metals. The hydrolysis rate of reaction can be reduced by using driers to reduce the free water concentration and by using scavenging chemicals which react with the system acids. Total acid number (TAN), which includes both mineral acids and organic acids, is therefore a useful indicator which can be used to monitor the condition of the system in order to perform remedial maintenance, when required, to prevent system failure. The critical TAN value is the acid level at which remedial action should be taken to prevent the onset of rapid acid formation which can result in system failure. The level of 0.05 mg KOH/g of oil was established for CFC/mineral oil systems based on analysis of 700 used lubricants from operating systems and failed units. There is no consensus within the refrigeration industry as to the critical TAN value for HFC/POE systems, however, the value will be higher than the CFC/mineral oil systems critical TAN value because of the much weaker organic acids produced from POE. A similar study of used POE lubricants should be performed to establish a critical TAN limit for POE systems. Titrimetric analysis per ASTM procedures is the most commonly used method to determine TAN values in lubricants in the refrigeration industry and other industries dealing with lubricating oils. For field measurements, acid test kits are often used since they provide rapid, semi-quantitative TAN results.

  11. Cryogenic refrigeration apparatus

    DOEpatents

    Crunkleton, James A. (Cambridge, MA)

    1992-01-01

    A technique for producing a cold environment in a refrigerant system in which input fluid from a compressor at a first temperature is introduced into an input channel of the system and is pre-cooled to a second temperature for supply to one of at least two stages of the system, and to a third temperature for supply to another stage thereof. The temperatures at such stages are reduced to fourth and fifth temperatures below the second and third temperatures, respectively. Fluid at the fourth temperature from the one stage is returned through the input channel to the compressor and fluid at the fifth temperature from the other stage is returned to the compressor through an output channel so that pre-cooling of the input fluid to the one stage occurs by regenerative cooling and counterflow cooling and pre-cooling of the input fluid to the other stage occurs primarily by counterflow cooling.

  12. The Quantum Absorption Refrigerator

    E-print Network

    Amikam Levy; Ronnie Kosloff

    2011-11-09

    A quantum absorption refrigerator driven by noise is studied with the purpose of determining the limitations of cooling to absolute zero. The model consists of a working medium coupled simultaneously to hot, cold and noise baths. Explicit expressions for the cooling power are obtained for Gaussian and Poisson white noise. The quantum model is consistent with the first and second laws of thermodynamics. The third law is quantified, the cooling power J_c vanishes as J_c proportional to T_c^{alpha}, when T_c approach 0, where alpha =d+1 for dissipation by emission and absorption of quanta described by a linear coupling to a thermal bosonic field, where d is the dimension of the bath.

  13. Comparison of solid-state thermionic refrigeration with thermoelectric refrigeration

    Microsoft Academic Search

    Marc D. Ulrich; Peter A. Barnes; Cronin B. Vining

    2001-01-01

    A theoretical analysis of single-barrier thermionic emission cooling in semiconducting materials is performed using Fermi–Dirac statistics. Both maximum cooling and coefficient of performance are evaluated. It is shown that the performance of a thermionic refrigerator is governed by the same materials factor as thermoelectric devices. For all known materials, single-barrier thermionic refrigeration is less effective and less efficient than thermoelectric

  14. Comparison of solid-state thermionic refrigeration with thermoelectric refrigeration

    Microsoft Academic Search

    Marc D. Ulrich; Peter A. Barnes; Cronin B. Vining

    2001-01-01

    A theoretical analysis of single-barrier thermionic emission cooling in semiconducting materials is performed using Fermi-Dirac statistics. Both maximum cooling and coefficient of performance are evaluated. It is shown that the performance of a thermionic refrigerator is governed by the same materials factor as thermoelectric devices. For all known materials, single-barrier thermionic refrigeration is less effective and less efficient than thermoelectric

  15. 63 FR 32044 - Protection of Stratospheric Ozone; Refrigerant Recycling; Substitute Refrigerants

    Federal Register 2010, 2011, 2012, 2013, 2014

    1998-06-11

    ...refrigerant applications, such as fertilizer and common household cleaner, but these...selective removal of components with higher solubility in oil through oil separation...the vapor phase of refrigerants. The solubility of air in the refrigerants liquid...

  16. Thermoacoustic refrigerator for space applications

    NASA Astrophysics Data System (ADS)

    Garrett, Steven L.; Adeff, Jay A.; Hofler, Thomas J.

    1993-10-01

    A new spacecraft cryocooler which uses resonant high-amplitude sound waves in inert gases to pump heat is described. 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). A space-qualified thermoacoustic refrigerator was flown on the Space Shuttle Discovery (STS-42) in January, 1992. It was entirely autonomous, had no sliding seals, required no lubrication, used mostly low-tolerance machined parts, and contained no expensive components. Thermoacoustics is shown to be a competitive candidate for food refrigerator/freezers and commercial/residential air conditioners. The design and performance of the Space Thermo/Acoustic Refrigerator (STAR) is described.

  17. Magnetic refrigeration apparatus and method

    DOEpatents

    Barclay, John A. (Los Alamos, NM); Overton, Jr., William C. (Los Alamos, NM); Stewart, Walter F. (Los Alamos, NM)

    1984-01-01

    The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

  18. 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).

  19. Thermoelectric refrigerator for gas analyzer

    Microsoft Academic Search

    G. V. Bochin; V. I. Butyrskii; L. N. Karaseva

    1987-01-01

    The authors describe a thermoelectric refrigerator for an air analyzer which cools an airstream by 24-30.4 K for a flow rate of 0.3 m³\\/h and a power consumption of less than or equal to 33.2 W. The setup time is 45 minutes. This refrigerator makes it possible to increase the average temperature of the heat-absorbing junction of the thermopile and

  20. Short-Cycle Adsorption Refrigerator

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1988-01-01

    Modular adsorption/Joule-Thomson-effect refrigerator offers fast regeneration; adsorption/desorption cycle time expected to be 1 minute. Pressurized hydrogen generated by bank of compressor modules during heating phase passes through system of check valves and expands in Joule-Thomson junction as it enters refrigeration chamber. Hydrogen absorbs heat from load before it is sucked out by another bank of compressor modules in cooling phase.

  1. Adsorbability of 1,1,1,2-Tetrafluoromethane (HFC134a) onto Plasma-Treated Activated Carbon in CF4 and CCl4

    PubMed

    Tanada; Kawasaki; Nakamura; Ohue; Abe

    1997-07-15

    The adsorbability of 1,1,1,2-tetrafluoroethane (HFC134a), which has been the CFC12 replacement, onto tetrafluoromethane and tetrachloromethane plasma-treated activated carbon (FT-ACs and CT-ACs) was investigated. It is proved that the fluorine and the chlorine, which were produced by plasma treatment, were introduced into the pores having radii greater 7.5 A and with less than 7.5 A by plasma treatment, respectively. The adsorption site of HFC134a onto activated carbon may change with the quantities of fluorine or chlorine on the surface of the activated carbon. The amount of HFC134a adsorbed per unit specific surface area of FT-ACs and CT-ACs slightly increased a little compared to the untreated activated carbon (U-AC). The amount of fluoride ion eluted before the adsorption of HFC134a from the FT-ACs increased with the increasing plasma treatment time. That after the adsorption of HFC134a from only the activated carbon with the shortest plasma treatment time decreased. The amount of chloride ion eluted before the adsorption of HFC134a from the CT-ACs increased after 15 min of plasma treatment, but decreased with 30 min of plasma treatment. The chloride ion amount from the CT-ACs decreased after the adsorption of HCF134a. These results could be explained by the Langmuir constants a and Ws, which represent the adsorption equilibrium constant and the saturated amount of HFC134a adsorbed, respectively. The ratio of fluorine and chlorine species, the adsorption type, the layer interstitial type, and the covalent type, is different based on the plasma treatment time. It is concluded that the amount of HFC134a adsorbed onto the FT-ACs and CT-ACs did not depend upon the change of pore structure by the fluorine and chlorine. PMID:9268515

  2. Optimal performance of a thermoelectric refrigerator

    SciTech Connect

    Chen, J.; Yan, Z. [Department of Physics, Xiamen University, Xiamen 361005 (China)

    1994-08-10

    The optimal performance of a thermoelectric device used as a refrigerator is discussed by using the rate of refrigeration and the coefficient of performance of the refrigerator under the influence of three main irreversibilities which are heat conduction, heat leak, and Joule heat. The coefficient of performance and the operating current of the refrigerator at the maximum rate of refrigeration and the operating current of the refrigerator at the maximum coefficient of performance. The reasonable ranges of the coefficient of performance, the rate of refrigeration, and the operating current for the refrigerator are determined. The results obtained here have more instructive meaning than those of non-equilibrium thermodynamics for the optimal design and operation of practical thermoelectric refrigerators. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  3. Measurements of the Vapor-Liquid Coexistence Curves and the Critical Parameters of HCFC123 and HFC134a

    NASA Astrophysics Data System (ADS)

    Fukushima, Masato; Watanabe, Naohiro; Kamimura, Toru

    The critical parameters and vapor-liquid coexistence curves in the critical region of two environmentally acceptable hydrogen-containing halocarbons (HCFC123 and HFC134a) were determined experimentally. The measurements of vapor-liquid coexistence curves were made through visual observation of the disappearance of meniscus at the vapor-liquid interface within the optical cell. Thirty eight saturated densities in the range of 209 to 1176 kg/m3 were obtained between the temperature of 392 K and the critical temperature for HCFC123. And seventeen saturated densities in the range of 322 to 746 kg/m3 were obtained between the temperature of 370 K and the critical temperature for HFC134a. On the basis of these results, the critical temperature and critical density of HCFC123 were determined to be 456.94 K and 553 kg/m3, respectively. And these parameters of HFC134a were determined to be 374.18 K and 507 kg/m3. In addition, the critical exponents were determined and the correlation of vapor-liquid coexistence curves were developed.

  4. Extrinsic allergic alveolitis with eosinophil infiltration induced by 1,1,1,2-tetrafluoroethane (HFC-134a): a case report.

    PubMed

    Ishiguro, Takashi; Yasui, Masahide; Nakade, Yusuke; Kimura, Hideharu; Katayama, Nobuyuki; Kasahara, Kazuo; Fujimura, Masaki

    2007-01-01

    A 22-year-old woman was admitted with symptoms of dyspnea and fever with pulmonary infiltrates noted on her chest X-ray study. She developed these symptoms in the workplace; her job included the removal of body hair using a diode-laser with 1,1,1,2-tetrafluoroethane (HFC134a, an alternative to chlorofluorocarbon) as a coolant. A chest X-ray examination revealed ground-glass opacities in the lower lung fields, and a chest computed tomographic study showed diffuse centrilobular opacities. An examination of the bronchoalveolar lavage fluid revealed increased lymphocytes with a slight increase in the number of eosinophils. An examination of the transbronchial biopsy specimens revealed eosinophil infiltration. A peripheral blood eosinophilia was also seen. The patient's symptoms, chest X-ray findings, and arterial blood gas analysis all returned to normal within a week. A challenge test of 1,1,1,2-tetrafluoroethane (HFC134a) inhalation was performed, which resulted in an elevation of body temperature, the development of a cough, and laboratory data indicating increased inflammation. We then determined the patient's diagnosis to be extrinsic allergic alveolitis with eosinophil infiltration, caused by HFC134a. PMID:17827848

  5. Measurements of HFC-134a and HCFC-22 in groundwater and unsaturated-zone air: implications for HFCs and HCFCs as dating tracers

    USGS Publications Warehouse

    Haase, Karl B.; Busenberg, Eurybiades; Plummer, L. Niel; Casile, Gerolamo; Sanford, Ward E.

    2014-01-01

    A new analytical method using gas chromatography with an atomic emission detector (GC–AED) was developed for measurement of ambient concentrations of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) in soil, air, and groundwater, with the goal of determining their utility as groundwater age tracers. The analytical detection limits of HCFC-22 (difluorochloromethane, CHClF2) and HFC-134a (1,2,2,2-tetrafluoroethane, C2H2F4) in 1 L groundwater samples are 4.3 × 10? 1 and 2.1 × 10? 1 pmol kg? 1, respectively, corresponding to equilibrium gas-phase mixing ratios of approximately 5–6 parts per trillion by volume (pptv). Under optimal conditions, post-1960 (HCFC-22) and post-1995 (HFC-134a) recharge could be identified using these tracers in stable, unmixed groundwater samples. Ambient concentrations of HCFC-22 and HFC-134a were measured in 50 groundwater samples from 27 locations in northern and western parts of Virginia, Tennessee, and North Carolina (USA), and 3 unsaturated-zone profiles were collected in northern Virginia. Mixing ratios of both HCFC-22 and HFC-134a decrease with depth in unsaturated-zone gas profiles with an accompanying increase in CO2 and loss of O2. Apparently, ambient concentrations of HCFC-22 and HFC-134a are readily consumed by methanotrophic bacteria under aerobic conditions in the unsaturated zone. The results of this study indicate that soils are a sink for these two greenhouse gases. These observations contradict the previously reported results from microcosm experiments that found that degradation was limited above-ambient HFC-134a. The groundwater HFC and HCFC concentrations were compared with concentrations of chlorofluorocarbons (CFCs, CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6). Nearly all samples had measured HCFC-22 or HFC-134a that were below concentrations predicted by the CFCs and SF6, with many samples showing a complete loss of HCFC-22 and HFC-134a. This study indicates that HCFC-22 and HFC-134a are not conservative as environmental tracers and leaves in question the usefulness of other HCFCs and HFCs as candidate age tracers.

  6. A ``Dilution Refrigerator'' Using Spin-Polarized Fermions

    NASA Astrophysics Data System (ADS)

    Basu, Sourish; Mueller, Erich J.

    2009-05-01

    We present an analogy between a population imbalanced two component Fermi gas on the BEC side of a Feshbach resonance and a ^3He-^4He mixture. The bosonic pairs are analogous to ^4He and the fermionic unpaired atoms to ^3He. These systems have topologically indistinguishable phase diagrams: at low temperatures the system phase separates into a fermion rich and a fermion poor region. As in standard cryogenic setups, one can in principle create a refrigerator which cools based upon the fact that there is a latent heat associated with pulling particles from the fermion rich region into the fermion poor one. We explore this idea, calculating the entropy of mixing, and suggesting cold atom geometries which mimic the anatomy of a standard ^3He-^4He dilution refrigerator.

  7. Superfluid orifice pulse tube refrigerator below 1 kelvin

    SciTech Connect

    Watanabe, A.; Swift, G.W.; Brisson, J.G. [Los Alamos National Lab., NM (United States)

    1996-12-31

    Half the moving parts of the superfluid Stirling refrigerator have been eliminated by adopting an orifice-pulse-tube configuration. The authors first such device has cooled to 0.64 K with the hot platform anchored at 1.0 K. Performance of the refrigerator is in reasonable agreement with expectations. Two curious features of the superfluid pulse tube are in distinct contrast with features of conventional pulse tubes. First, stability of the {sup 3}He-{sup 4}He mixture against free convection requires that the hot end of the pulse tube must be below the cold end. Second, the low heat capacity of metals below 1 K makes heat loss along the pulse tube due to the fluid`s oscillatory motion very small.

  8. Superinsulation in refrigerators and freezers

    SciTech Connect

    Vineyard, E.; Stovall, T.K.; Wilkes, K.E.; Childs, K.W.

    1998-02-01

    The results presented here were obtained during Phase 4 of the first CRADA, which had the specific objective of determining the lifetime of superinsulations when installed in simulated refrigerator doors. The second CRADA was established to evaluate and test design concepts proposed to significantly reduce energy consumption in a refrigerator-freezer that is representative of approximately 60% of the US market. The stated goal of this CRADA is to demonstrate advanced technologies which reduce, by 50%, the 1993 National Appliance Energy Conservation Act (NAECA) standard energy consumption for a 20 ft{sup 3} (570 L) top-mount, automatic-defrost, refrigerator-freezer. For a unit this size, the goal translates to an energy consumption of 1.003 kWh/d. The general objective of the research is to facilitate the introduction of efficient appliances by demonstrating design changes that can be effectively incorporated into new products. In previous work on this project, a Phase 1 prototype refrigerator-freezer achieved an energy consumption of 1.413 kWh/d [Vineyard, et al., 1995]. Following discussions with an advisory group comprised of all the major refrigerator-freezer manufacturers, several options were considered for the Phase 2 effort, one of which was cabinet heat load reductions.

  9. Thermoelectric refrigerator having improved temperature stabilization means

    DOEpatents

    Falco, Charles M. (Woodridge, IL)

    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.

  10. Energy Saving with Absorption Refrigeration Technologies 

    E-print Network

    Davis, R. C.

    1984-01-01

    Absorption refrigeration technology can be an economical and cost effective means of reducing energy cost and/or improving the efficiency and output of your process. We believe the potential benefits of absorption refrigeration technology have...

  11. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage...includes a compressor and its motors and controls. (c) Each refrigeration system must...are compatible with the cargo and, for cascade units, with each other. (f)...

  12. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Equipment Cargo Pressure and Temperature Control § 154.702 Refrigerated carriage...includes a compressor and its motors and controls. (c) Each refrigeration system must...are compatible with the cargo and, for cascade units, with each other. (f)...

  13. 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.

  14. 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...

  15. Buy-back program recycles old refrigerators

    Microsoft Academic Search

    Musick

    1991-01-01

    A refrigerator Buy-Back Program was initiated by the regional power utility, BC Hydron in 1990, with six pilot collection areas in British Columbia. As a result of the program's initial success, BC Hydro started a facility to dismantle old refrigerators, and the utility plans to expand its Refrigerator Buy-Back Program province-wide. BC Hydro's Refrigerator Buy-Back is the first utility-sponsored program

  16. Pressure-enthalpy diagrams for alternative refrigerants

    Microsoft Academic Search

    J. Chen; H. Kruse

    1996-01-01

    Thermodynamic diagrams, particularly log(p)-h diagrams, have become very convenient tools for refrigeration and air-conditioning industries. To promote alternative refrigerants-related development and application, it is urgently required to provide the industries with reliable engineering diagrams for the most promising candidate refrigerants. A computer program has been developed for automatically producing log(p)-h diagrams for alternative refrigerants. The Lee Kesler Ploecker (LKP) equation

  17. 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.

  18. Review of materials for adsorption refrigeration technology

    Microsoft Academic Search

    M. A. Alghoul; M. Y. Sulaiman; B. Z. Azmi; K. Sopian; M. Abd. Wahab

    2007-01-01

    Purpose – During the last 20 years, interest in the closed adsorption heat pump and refrigeration systems has increased steadily. In this paper, consideration is given to aspects of adsorption refrigeration in terms of existing materials used in adsorption refrigeration, heat transfer characteristics of materials, and cost of materials and manufacturing. Design\\/methodology\\/approach – The paper is a general review of

  19. Optimal synthesis of integrated refrigeration systems

    Microsoft Academic Search

    1985-01-01

    The object of this research work is to develop systematic procedures for the synthesis of refrigeration systems that are integrated with the heat recovery network. In this dissertation, methods are developed for the optimization of integrated refrigeration systems. As a first step, a shortcut model for predicting the performance of vapor-compression refrigeration cycles is developed. This model which requires only

  20. Free convection heat transfer thermoelectric refrigerators

    Microsoft Academic Search

    I. I. Sochard

    1962-01-01

    Optimization equations for free convection heat transfer thermoelectric refrigerators have been derived and used to design several units. These devices successfully eliminate the blowers usually required for substantial performance in thermoelectric refrigerators. This results in totally silent operation and an indefinite operating life. The over-all power requirement is also reduced. A characteristic of these refrigerators is that substantial heat must

  1. Ideal orifice pulse tube refrigerator performance

    NASA Technical Reports Server (NTRS)

    Kittel, P.

    1992-01-01

    The recent development of orifice pulse tube refrigerators has raised questions as to what limits their ultimate performance. Using an analogy to the Stirling cycle refrigerator, the efficiency (cooling power per unit input power) of an ideal orifice pulse tube refrigerator is shown to be T1/T0, the ratio of the cold temperature to the hot temperature.

  2. New refrigeration system using CO 2 vapor-solid as refrigerant

    Microsoft Academic Search

    Dongping Huang; Guoliang Ding; Hans Quack

    2008-01-01

    A refrigerant must be in the vapor-liquid phase in a vapor-compression refrigeration system, therefore, CO2 cannot be used as a refrigerant for temperatures lower than 256uC because solid CO2 will form under the triple point temperature of 256uC. A refrigeration system with CO2 vapor-solid particles as refrigerant is put forward, by which a temperature lower than the triple point is

  3. Formation of fluorinated nonionic surfactant microemulsions in hydrofluorocarbon 134a (HFC 134a).

    PubMed

    Patel, Nilesh; Marlow, Maria; Lawrence, M Jayne

    2003-02-15

    A structurally related series of fluorinated nonionic oxyethylene glycol surfactants of the type C(m)F(2m+1)(CH(2))(n)O[(CH(2)CH(2)O)(p)H], denoted C(m.n)E(p) (where m=4, 6, or 7, m=1 or 2, and p=4 or 6) were synthesized and their surface behavior in aqueous solution was characterized. The ability of these surfactants to form water-in-hydrofluorocarbon (HFC) propellant 134a microemulsions suitable for use in the aerosolized delivery of water-soluble drugs has been investigated. Phase studies showed that, regardless of the composition used, clear one-phase systems could not be prepared if a fluorinated nonionic surfactant was used alone, or in combination with a short or medium fluorocarbon alcohol cosurfactant. Clear one-phase systems could, however, be prepared if a short-chain hydrocarbon alcohol, such as ethanol, n-propanol, or n-pentanol, was used as cosurfactant, with the extent of the one-phase region increasing with decreased chain length of the alcohol cosurfactant. Light-scattering studies on a number of the hydrocarbon-alcoholcontaining systems in the propellant-rich part of the phase diagram showed that only systems prepared with C(4.2)E(6) and propanol contained microemulsion droplets (all other systems investigated were considered to be cosolvent systems). PMID:12618104

  4. 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.

  5. Performance modeling of optical refrigerators

    Microsoft Academic Search

    Gary Mills; Allan Mord

    2006-01-01

    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

  6. 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.

  7. Energy Efficient, Environmentally Friendly Refrigerants

    E-print Network

    Nimitz, J.; Glass, S.; Dhooge, P. M.

    , low global warming potential, relatively low toxicity, is compatible with most common refrigeration system materials of construction, and is thermally stable. Ikon B was used as a drop-in replacement for R-12 in an instrumented 1.5 ton chiller...

  8. Low-temperature magnetic refrigerator

    DOEpatents

    Barclay, John A. (Los Alamos, NM)

    1985-01-01

    The disclosure is directed to a low temperature 4 to 20 K. refrigeration apparatus and method utilizing a ring of magnetic material moving through a magnetic field. Heat exchange is accomplished in and out of the magnetic field to appropriately utilize the device to execute Carnot and Stirling cycles.

  9. A review of thermoelectric refrigeration

    Microsoft Academic Search

    R. L. Eichhorn

    1963-01-01

    The advantages of thermoelectric refrigeration, some of its possible applications and its principles of operation are briefly presented. The current state of the art in thermoelectric materials is discussed. The design problems in developing thermoelectric devices and some of the current techniques used to solve them are reviewed. Some information is provided on devices that have been built for the

  10. Evaluation on environment-friendly refrigerants with similar normal boiling points in ejector refrigeration system

    NASA Astrophysics Data System (ADS)

    Wang, F.; Shen, S. Q.; Li, D. Y.

    2014-12-01

    Based on the "hypothetical throat area" theory and the "constant-pressure mixing" theory, a thermodynamic model for ejector was set up by introducing the real properties of refrigerants. Refrigerants which have similar normal boiling points with each other may act as replacement to each other in substitute progress. In this paper, eight environment-friendly refrigerants were divided into 4 pairs for study according to their normal boiling point. In each refrigerant pair, the entrainment ratios of ejector, system COP, pump power et al. of refrigerants were compared and analyzed. Lastly, the performances of the transcritical and subcritical ejector refrigeration cycles with propylene were calculated and compared.

  11. Dual mixed refrigerant natural gas liquefaction with staged compression

    Microsoft Academic Search

    1985-01-01

    An apparatus and process for liquefying natural gas using two closed-cycle, multicomponent refrigerants; a low level refrigerant which cools the natural gas and a high level refrigerant which cools the low level refrigerant wherein the improvement comprises phase separating the high level refrigerant after compression and fully liquefying the vapor phase stream against external cooling fluid after additional compression.

  12. A note on the Ericsson refrigeration cycle of paramagnetic salt

    Microsoft Academic Search

    Zijun Yan; Jincan Chen

    1989-01-01

    The magnetic Ericsson refrigeration cycle is a significant cycle in the research and manufacture of magnetic refrigerators. The distinctive advantage of magnetic refrigerators is that they offer the possibility of much greater operating efficiency and reliability than that currently available in conventional helium-gas refrigerators. It is pointed out here that the Ericsson refrigeration cycle of a simple paramagnetic salt cannot

  13. Profitability of using solar energy for refrigeration and air conditioning

    Microsoft Academic Search

    S. Ajib

    2001-01-01

    In this paper we analyze the use of solar thermal energy to operate the absorption refrigeration machines for refrigeration and air conditioning and with respect to their rentability. Furthermore the different drive systems of absorption refrigeration machines and vapour-compression refrigeration machines are compared under the assumption of equal refrigeration capacity for all systems. As an example for the energetic and

  14. ASHRAE/NIST Refrigerants Conference International concerns about the impact of refrigerants on climate change drive the

    E-print Network

    Ginzel, Matthew

    on Refrigerant Preferences and Refrigeration and Air Conditioning in 2032. Keynote Presentations James CalmASHRAE/NIST Refrigerants Conference International concerns about the impact of refrigerants on climate change drive the need to look at new cooling and refrigeration options that are sustainable

  15. Haptic simulation of refrigerator door

    Microsoft Academic Search

    Sunghwan Shin; In Lee; Hojin Lee; Gabjong Han; Kyungpyo Hong; Sunghoon Yim; Jongwon Lee; YoungJin Park; Byeong Ki Kang; Dae Ho Ryoo; Dae Whan Kim; Seungmoon Choi; Wan Kyun Chung

    2012-01-01

    Recently, haptics has begun to impact consumer products, e.g., mobile phones and automobiles. In this paper, we introduce one such new application, that is, haptic simulation of refrigerator operation, and present an initial prototype for the front door. A one degree-of-freedom haptic interface is designed and built to provide torque feedback of the front door. Simulation software consisting of system

  16. Suction muffler for refrigeration compressor

    DOEpatents

    Nelson, Richard T. (Worthington, OH); Middleton, Marc G. (West Jefferson, OH)

    1983-01-01

    A hermetic refrigeration compressor includes a suction muffler formed from two pieces of plastic material mounted on the cylinder housing. One piece is cylindrical in shape with an end wall having an aperture for receiving a suction tube connected to the cylinder head. The other piece fits over and covers the other end of the cylindrical piece, and includes a flaring entrance horn which extends toward the return line on the sidewall of the compressor shell.

  17. Thermodynamic improvements for the space thermo-acoustic refrigerator (STAR). Master's thesis

    SciTech Connect

    Susalla, M.P.

    1988-06-01

    The objective of the STAR project is to test and space qualify a new continuous-cycle cryogenic refrigeration system for cooling of sensors and electronics which is based upon the newly discovered thermoacoustic heat-pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 Hz, and uses acoustic resonance to enhance the overall power density and efficiency. This thesis is concerned specifically with the design and testing of the thermodynamic element (or stack), which is responsible for the thermo-acoustic power conversion, and the testing of binary inert-gas mixtures as working fluids. Using the refrigerator's coefficient of performance relative to the ideal Carnot coefficient of performance as a measure of efficiency, a 93% improvement over previous designs.

  18. High frequency thermoacoustic refrigerator. Annual summary report, 2 September 1993-31 May 1994

    SciTech Connect

    Symko, O.G.

    1994-06-16

    A small thermoacoustic refrigerator was developed for operation at 5 kHz. Its main components are a piezoelectric driver of the bimorph type, a cotton wool stack, a 1/2-wave resonator (operated at its 3rd harmonic), and photolithographically processed copper heat exchangers. Tests with air at 1 atmosphere as the working gas produced a temperature difference Delta T across the stack of 32 deg C in 4 seconds for an acoustic power input level of 160 dB. The refrigerator did not have thermal insulation. Improved performance is expected with pressurized helium gas and helium-xenon mixtures. The performance of this refrigerator and its small size make it attractive for applications in high speed electronics and possibly IR detectors.

  19. Miscibility of lubricants with refrigerants, Phase 1. Final report, 6 February 1992--15 October 1992

    SciTech Connect

    Pate, M.B.; Zoz, S.C.; Berkenbosch, L.J. [Iowa State Univ. of Science and Technology, Ames, IA (United States). Dept. of Agricultural Engineering

    1992-10-01

    Miscibility data have been obtained for a variety of non-CFC refrigerants and their potential lubricants. Ten different refrigerants and seven different lubricants were investigated. Experiments are being performed in two phases: Phase I, reported herein, focuses on performing screening tests for miscibility and Phase II consists of developing miscibility plots. The miscibility tests are being performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The bath temperature can be precisely controlled over a temperature range of -50 C to 90C(-58 F to 194 F). The test cells are constructed to allow for complete visibility of lubricant-refrigerant mixtures under all test conditions.

  20. The ISM equation of state applied to refrigerants

    SciTech Connect

    Eslami, H.; Sabzi, F.; Boushehri, A.

    1999-09-01

    In this work, the authors apply an equation of state based on statistical-mechanical perturbation theory to liquid refrigerants and their mixtures. Three temperature-dependent parameters are needed to use the equation of state: the second virial coefficient, B{sub 2}(T), an effective van der Waals covolume, b(T), and a scaling factor, {alpha}(T). The second virial coefficients are calculated from a correlation based on the heat of vaporization, {Delta}H{sub vap}, and the liquid density at the freezing point, p{sub fp}. {alpha}(T) and {beta}(T) can also be calculated from the second virial coefficient by a scaling rule. Based on the theory, these two temperature-dependent parameters depend only on the repulsive branch of the potential function, and therefore, by the procedure, can be found from {Delta}H{sub vap} and p{sub fp}. The theory has considerable predictive power, since it permits the construction of the p-v-T surface from the heat of vaporization plus the triple-point density. The equation of state is tested for pure, two- and three-component liquid refrigerant mixtures.

  1. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

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

    1992-07-01

    Information contained in this reporters 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. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have 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 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  2. Cryogen-free dilution refrigerators

    NASA Astrophysics Data System (ADS)

    Uhlig, K.

    2012-12-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 ?W at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  3. Optimization of characteristics of refrigerating machine operating with recharging of compressor cylinder with refrigerant

    Microsoft Academic Search

    G. K. Lavrenchenko

    2008-01-01

    The results of scientific and technical research for improving the characteristics of small refrigerating machines (SRM) by\\u000a adapting them to effective natural refrigerants (R600a and R600) are reported. A method, which consists in recharging (supplementary\\u000a charging) of the compressor cylinder with a refrigerant in a Voorhees refrigerating machine, has been proposed for reducing\\u000a losses in the compressor. The results of

  4. Environmental fate of the next generation refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf).

    PubMed

    Im, Jeongdae; Walshe-Langford, Gillian E; Moon, Ji-Won; Löffler, Frank E

    2014-11-18

    The hydrofluoroolefin 2,3,3,3-tetrafluoropropene (HFO-1234yf) has been introduced to replace 1,1,1,2-tetrafluoroethane (HFC-134a) as refrigerant in mobile, including vehicle, air conditioning systems because of its lower global warming potential. HFO-1234yf is volatile at ambient temperatures; however, high production volumes and widespread handling are expected to release this fluorocarbon into terrestrial and aquatic environments, including groundwater. Laboratory experiments explored HFO-1234yf degradation by (i) microbial processes under oxic and anoxic conditions, (ii) abiotic processes mediated by reactive mineral phases and zerovalent iron (Fe(0), ZVI), and (iii) cobalamin-catalyzed biomimetic transformation. These investigations demonstrated that HFO-1234yf was recalcitrant to microbial (co)metabolism and no transformation was observed in incubations with ZVI, makinawite (FeS), sulfate green rust (GR(SO4)), magnetite (Fe(3)O(4)), and manganese oxide (MnO2). Sequential reductive defluorination of HFO-1234yf to 3,3,3-trifluoropropene and 3,3-dichloropropene with concomitant stoichiometric release of fluoride occurred in incubations with reduced cobalamins (e.g., vitamin B12) indicating that biomolecules can transform HFO-1234yf at circumneutral pH and at ambient temperature. Taken together, these findings suggest that HFO-1234yf recalcitrance in aquifers should be expected; however, HFO-1234yf is not inert and a biomolecule may mediate reductive transformation in low redox environments, albeit at low rates. PMID:25329364

  5. Heat Pipe Applications in Sorption Refrigerators

    Microsoft Academic Search

    L. L. Vasiliev; A. G. Kulakov

    \\u000a Some sorption refrigeration machines (sorption technologies) developed in Belarus are presented in this paper with emphasises\\u000a on different heat pipes application: conventional heat pipes, heat pipe panels, loop heat pipes, vapour-dynamic thermosyphons,\\u000a etc. Heat pipes are very flexible systems with regards to the effective thermal control. They can easily be implemented inside\\u000a sorption refrigerators and other types of refrigerators [1].

  6. Equivalent Carnot cycles for sorption refrigeration

    Microsoft Academic Search

    F. Meunier; P. Neveu; J. Castaing-Lasvignottes

    1998-01-01

    Temperature–entropy diagrams are usually used to describe heat-driven engines as well as vapour compressor refrigerators, but they have not yet been used for sorption refrigeration. Such Carnot cycles are introduced here to describe three sorption refrigeration technologies (liquid absorption, solid adsorption, chemical reaction). This is performed for basic cycles (without heat recovery) and for simple advanced cycles. Equivalent four-temperature Carnot

  7. Thermodynamic investigation for developing solar refrigerator

    Microsoft Academic Search

    A. A. Missallam; O. M. Algero

    2010-01-01

    The present study uses basic thermodynamic relationships capable of assisting in the design of a solar refrigerator for agricultural\\u000a products refrigeration. The data used for calculation are daily average meteorological data collected over a period of five\\u000a years in Hun city in Lybia, taking 1988 as a reference year and 2000 to 2003 for comparison. The investigated adsorption refrigeration\\u000a cycle

  8. Experimental investigation of the performance of a single-stage auto-cascade refrigerator

    NASA Astrophysics Data System (ADS)

    Rui, Shengjun; Zhang, Hua; Zhang, Bohan; Wen, Dongsheng

    2015-05-01

    Auto-refrigerating cascade (ARC) systems possess many advantages comparing with traditional cascade refrigeration systems. This work proposed a novel ternary mixture, R600a/R23/R14, for ARC systems for 190 K applications. The performance of the ternary mixture and the influences of compositional ratio and bypass scheme were assessed in a modified domestic cooler. The results demonstrated the feasibility of the proposed R600a/R23/R14 ternary mixture as an environmental benign alternative for ARC systems. The performance varied little within a certain composition range and a mass ratio of 35/30/35 for R600a/R23/R14 mixture was recommended. It also showed that the two bypass schemes, which can regulate more effectively the refrigerant compositions, were better than the conventional hot-gas bypass approach. The variation of the evaporator temperature suggested the presence of local dryout at high heat loads (i.e., larger than the design value), which should be carefully prevented.

  9. M. Bahrami ENSC 461 (S 11) Refrigeration Cycle 1 Refrigeration Cycle

    E-print Network

    Bahrami, Majid

    is called a Carnot refrigerator or a Carnot heat pump. Fig. 5-1: T-s diagram and major components for Carnot-h diagrams for an ideal vapor-compression refrigeration cycle. 1-2: A reversible, adiabatic (isentropic and pressure decrease at constant enthalpy. The refrigerant enters the evaporator at state 4 as a low

  10. Experimental study and comparison of thermochemical resorption refrigeration cycle and adsorption refrigeration cycle

    Microsoft Academic Search

    T. X. Li; R. Z. Wang; J. K. Kiplagat; H. Chen

    2010-01-01

    The cycle characteristics of thermochemical resorption refrigeration system were investigated, and the experimental comparison between the basic resorption cycle and adsorption cycle was performed. Experimental results showed that the conversion rate during the regeneration phase in the resorption refrigeration cycle was higher than that in the adsorption refrigeration cycle at the same constraining temperatures. However, the conversion rate was lower

  11. 49 CFR 179.102-1 - Carbon dioxide, refrigerated liquid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Carbon dioxide, refrigerated liquid. 179...114 and 120) § 179.102-1 Carbon dioxide, refrigerated liquid. (a) Tank cars used to transport carbon dioxide, refrigerated liquid...

  12. 49 CFR 179.102-1 - Carbon dioxide, refrigerated liquid.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Carbon dioxide, refrigerated liquid. 179...114 and 120) § 179.102-1 Carbon dioxide, refrigerated liquid. (a) Tank cars used to transport carbon dioxide, refrigerated liquid...

  13. 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...

  14. 46 CFR 58.20-20 - Refrigeration piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Refrigeration piping. 58.20-20 Section 58.20-20 Shipping...Refrigeration Machinery § 58.20-20 Refrigeration piping. (a) All piping materials shall be suitable for handling...

  15. 46 CFR 58.20-20 - Refrigeration piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Refrigeration piping. 58.20-20 Section 58.20-20 Shipping...Refrigeration Machinery § 58.20-20 Refrigeration piping. (a) All piping materials shall be suitable for handling...

  16. 46 CFR 58.20-20 - Refrigeration piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Refrigeration piping. 58.20-20 Section 58.20-20 Shipping...Refrigeration Machinery § 58.20-20 Refrigeration piping. (a) All piping materials shall be suitable for handling...

  17. 49 CFR 179.102-17 - Hydrogen chloride, refrigerated liquid.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Hydrogen chloride, refrigerated liquid...114 and 120) § 179.102-17 Hydrogen chloride, refrigerated liquid. Each tank car used to transport hydrogen chloride, refrigerated liquid...

  18. 46 CFR 128.410 - Ship's service refrigeration systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated spaces for ship's stores need...chapter if— (a) The unit uses a fluorocarbon refrigerant allowed by part 147 of this chapter; (b)...

  19. 46 CFR 128.410 - Ship's service refrigeration systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated spaces for ship's stores need...chapter if— (a) The unit uses a fluorocarbon refrigerant allowed by part 147 of this chapter; (b)...

  20. 46 CFR 128.410 - Ship's service refrigeration systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...refrigeration systems. No self-contained unit either for air-conditioning or for refrigerated spaces for ship's stores need...chapter if— (a) The unit uses a fluorocarbon refrigerant allowed by part 147 of this chapter; (b)...

  1. 75 FR 29823 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...proposed rulemaking (NOPR) to amend the test procedures for refrigerators,...

  2. 78 FR 41609 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...notice of proposed rulemaking to amend the test procedures for refrigerators,...

  3. 75 FR 78809 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-16

    ...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...proposed rulemaking (NOPR) to amend the test procedures for refrigerators,...

  4. Improvement of the Performance for an Absorption Refrigeration System with Lithium bromide-water as Refrigerant by Increasing Absorption Pressure 

    E-print Network

    Xie, G.; Sheng, G.; Li, G.; Pan, S.

    2006-01-01

    Because the absorption refrigeration system uses the Lithium bromide- water solution as refrigerant, it is profitable for the environment that human beings are living since the values of ODP and GWP of the refrigerant almost are zero. However...

  5. Growth characteristics of Listeria monocytogenes as affected by a -native microflora in cooked ham under refrigerated and temperature abuse conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined the growth characteristics of L. monocytogenes as affected by a native microflora in cooked ham at refrigerated and abuse temperatures. A five-strain mixture of L. monocytogenes and a native microflora isolated from cooked meat were inoculated alone (monocultured) or co-inoculate...

  6. Continuous Crystallization of Urea-Water Mixture

    NASA Astrophysics Data System (ADS)

    Hokamura, Taku; Ohkubo, Hidetoshi; Watanabe, Satoshi; Seki, Mitsuo; Murakoshi, Hiromichi

    Ice slurries have been used as environmentally-friendly secondary refrigerants. In addition to such ice slurries, aqueous solutions in slurry-state have also been put to practical use at temperatures below 0 oC. Urea-water mixture is a multi-component substance that has a eutectic point. If we can form a two-phase fluid substance by the liquid-solid phases at the eutectic point, it can be used as a fluid latent heat storage material, which will maintain the secondary refrigerant in a heat exchanger at constant temperature. In the present study, we propose a urea-water mixture as a novel functional thermal fluid that can be used as a fluid latent heat material. To demonstrate its feasibility, we first measured the latent heat and density of a urea-water mixture, and then used a counter-flow double tube heat exchanger to produce a liquid-solid two-phase flow of the urea-water mixture. This work demonstrates that it is possible to make a fluid latent heat storage material continuously from an aqueous solution at the eutectic point by flowing it through a double tube heat exchanger equipped with a stirrer.

  7. Superconducting tunnel-junction refrigerator

    SciTech Connect

    Melton, R.G.; Paterson, J.L.; Kaplan, S.B.

    1980-03-01

    The dc current through an S/sub 1/-S/sub 2/ tunnel junction, with ..delta../sub 2/ greater than ..delta../sub 1/, when biased with eV<..delta../sub 1/+..delta../sub 2/, will lower the energy in S/sub 1/. This energy reduction will be shared by the phonons and electrons. This device is shown to be analogous to a thermoelectric refrigerator with an effective Peltier coefficient ..pi..* approx. ..delta../sub 1//e. Tunneling calculations yield the cooling power P/sub c/, the electrical power P/sub e/ supplied by the bias supply, and the cooling efficiency eta=P/sub c//P/sub e/. The maximum cooling power is obtained for eV= +- (..delta../sub 2/-..delta../sub 1/) and t/sub 1/=T/sub 1//T/sub c/1 approx. 0.9. Estimates are made of the temperature difference T/sub 2/-T/sub 1/ achievable in Al-Pb and Sn-Pb junctions with an Al/sub 2/O/sub 3/ tunneling barrier. The performance of this device is shown to yield a maximum cooling efficiency eta approx. = ..delta../sub 1//(..delta../sub 2/-..delta../sub 1/) which can be compared with that available in an ideal Carnot refrigerator of eta=T/sub 1//(T/sub 2/-T/sub 1/). The development of a useful tunnel-junction refrigerator requires a tunneling barrier with an effective thermal conductance per unit area several orders of magnitude less than that provided by the A1/sub 2/O/sub 3/ barrier in the Al-Pb and Sn-Pb systems.

  8. Asset Management Equipment Disposal Form -Refrigerant Recovery

    E-print Network

    Sin, Peter

    Asset Management Equipment Disposal Form - Refrigerant Recovery Safe Disposal Requirements Under EPA's rule, equipment that is typically dismantled on site before disposal (e.g., retail food the refrigerant recovered in accordance with EPA's requirements for servicing. However, equipment that typically

  9. Construction and performance of a thermoacoustic refrigerator

    Microsoft Academic Search

    M. E. H Tijani; J. C. H Zeegers; A. T. A. M de Waele

    2002-01-01

    This paper deals with the construction and performance of a thermoacoustic refrigerator. The manufacturing of the different components of the apparatus will be explained along with the reasons for using specific materials. The setup consists of three major parts: The refrigerator which is contained in a vacuum vessel, the electronic apparatus necessary for the measurements and acquisition of the experimental

  10. A solar and electrical solid sorption refrigerator

    Microsoft Academic Search

    Leonard Leonardovich Vasiliev; Donatos Algirdo Mishkinis; Alexander Antonovich Antukh; Leonid Leonardovich Vasiliev

    1999-01-01

    A new solar and electrical refrigerator based on solid sorption phenomena was designed and tested. This refrigerator has very short (15 min) non-intermittent two adsorber heat recovery cycles and uses an active carbon fibre as a sorbent bed and ammonia as a working fluid. The system management involves only the actuation of valves of special type to change the direction

  11. Experimental development of an intelligent refrigeration system

    Microsoft Academic Search

    L. O. S. Buzelin; S. C. Amico; J. V. C. Vargas; J. A. R. Parise

    2005-01-01

    In this study, an alternative solution to reduce energy consumption in industrial refrigeration systems is proposed and introduced. A typical industrial refrigeration system was conceived, built and modified in the laboratory, receiving a novel power law control system, which utilizes a frequency inverter. The operation and energy consumption of the system operating either with the new control system or with

  12. BNL Refrigerant Overview Presentation to the

    E-print Network

    Homes, Christopher C.

    temperature) to cold (low temperature). · To make heat flow from cold to hot, we must do work (add energy) to the cycle. Refrigerants are the "working fluids" in refrigeration, air conditioning and heat pumping systems between desirable / undesirable properties: · Thermal / physical properties (Boiling point? Freezing point

  13. Solar energy refrigeration and air conditioning system

    Microsoft Academic Search

    C. T. Pitts; H. A. Ingley; E. A. Farber; C. A. Morrison

    1977-01-01

    A solar energy refrigeration and air conditioning system for cooling an enclosed area comprising a low temperature vapor generator, condenser and evaporator specifically configured for use with a low boiling point refrigerant to use solar energy as a means of vapor generation is described. The low temperature vapor generator is coupled to an externally heated water source through a first

  14. The use of semiconductors in thermoelectric refrigeration

    Microsoft Academic Search

    H J Goldsmid; R W Douglas

    1954-01-01

    In the past the possibility of thermoelectric refrigeration has been considered, but all attempts to produce a practical refrigerator have failed owing to lack of suitable thermocouple materials. In this paper it is proposed that semiconductors should be used and the factors governing their selection are discussed. It is concluded that the semiconductors should be chosen with high mean atomic

  15. Design considerations for a thermoelectric refrigerator

    Microsoft Academic Search

    1995-01-01

    Heat transfer at a finite rate and electrical resistive losses are necessarily irreversible processes and unavoidable in a thermoelectric device. It is shown that the internal and exernal irreversibilities in a thermoelectric refrigerator may be characterized by a single parameter, named the device-design parameter. The presence of this parameter in the equations for the refrigeration effect and the maximum input

  16. Electricity for refrigeration and air conditioning

    Microsoft Academic Search

    1984-01-01

    This book consists of twenty-two units, each covering a specific area of this important part of the air conditioning and refrigeration industry. Each unit begins with an introduction to the particular phase of study and advances through the more technical aspects of electrical theory. Application of these theories to the air conditioning and refrigeration industry are made to aid the

  17. Energy use of icemaking in domestic refrigerators

    Microsoft Academic Search

    A. Meier; M. S. Martinez

    1996-01-01

    This study was designed to develop and test a procedure to measure the electrical consumption of ice making in domestic refrigerators. The Department of Energy (DOE) test procedure was modified to include the energy used for icemaking in conventional refrigerators and those equipped with automatic icemakers. The procedure assumed that 500 grams of ice would be produced daily. Using the

  18. Solubility correlation and phase behaviors of carbon dioxide and lubricant oil mixtures

    Microsoft Academic Search

    A. Yokozeki

    2007-01-01

    Recently, carbon dioxide is being considered as one of the promising environmentally-friendly refrigerants, and extensive studies on the “trans-critical” vapor-compression cycle using CO2 have been undertaken both experimentally and theoretically. In the vapor compression cycle, lubricant oils are always required, and thus thermophysical properties of lubricant and refrigerant mixtures must be well understood. Currently, the lubricants of choice are polyalkylene

  19. Sorption compressor/mechanical expander hybrid refrigeration

    NASA Technical Reports Server (NTRS)

    Jones, J. A.; Britcliffe, M.

    1987-01-01

    Experience with Deep Space Network (DSN) ground-based cryogenic refrigerators has proved the reliability of the basic two-stage Gifford-McMahon helium refrigerator. A very long life cryogenic refrigeration system appears possible by combining this expansion system or a turbo expansion system with a hydride sorption compressor in place of the usual motor driven piston compressor. To test the feasibility of this system, a commercial Gifford-McMahon refrigerator was tested using hydrogen gas as the working fluid. Although no attempt was made to optimize the system for hydrogen operation, the refrigerator developed 1.3 W at 30 K and 6.6 W at 60 K. The results of the test and of theoretical performances of the hybrid compressor coupled to these expansion systems are presented.

  20. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

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

    1993-01-01

    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. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have 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 from the refrigerant test fluids and 24 hours after removal from the lubricants.

  1. 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.

  2. A rocket-borne He-3 refrigerator

    NASA Technical Reports Server (NTRS)

    Duband, L.; Alsop, D.; Lange, A.; Kittel, P.

    1990-01-01

    A self-contained, recyclable He-3 refrigerator suitable for use in space has been developed. The refrigerator is compact, has no moving parts, and requires only electrical connections and thermal contact in order to operate from a 2 K cold stage. A charcoal adsorption pump is used to efficiently condense and cool the He-3. Sintered copper confines the He-3 to the evaporator in zero-gravity and, in fact, allows the refrigerator to operate upside-down in the laboratory. Mounted on a 2 K cold stage, the refrigerator provides 100 microwatts of cooling power at 346 mK, with a 7 hour hold time. On a 1.5 K cold stage, the lowest temperature achieved is 277 mK. The refrigerator has been vibration tested at 7.5 G amplitude from 30 to 400 Hz and 15 G amplitude from 400 to 2000 Hz.

  3. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

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

    1992-10-01

    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. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on the availability of additional quantities of R-32. Swell behavior in the fluids have 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 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  4. Novel materials for laser refrigeration

    SciTech Connect

    Hehlen, Markus P [Los Alamos National Laboratory

    2009-01-01

    The status of optical refrigeration of rare-earth-doped solids is reviewed, and the various factors that limit the performance of current laser-cooling materials are discussed. Efficient optical refrigeration is possible in materials for which {Dirac_h}{omega}{sub max} < E{sub p}/8, where {Dirac_h}{omega}{sub max} is the maximum phonon energy of the host material and E{sub p} is the pump energy of the rare-earth dopant. Transition-metal and OH{sup -}impurities at levels >100 ppb are believed to be the main factors for the limited laser-cooling performance in current materials. The many components of doped ZBLAN glass pose particular processing challenges. Binary fluoride glasses such as YF{sub 3}-LiF are considered as alternatives to ZBLAN. The crystalline system KPb{sub 2}CI{sub 5} :Dy{sup 3+} is identified as a prime candidate for high-efficiency laser cooling.

  5. Oil cooled, hermetic refrigerant compressor

    DOEpatents

    English, William A. (Murrysville, PA); Young, Robert R. (Murrysville, PA)

    1985-01-01

    A hermetic refrigerant compressor having an electric motor and compressor assembly in a hermetic shell is cooled by oil which is first cooled in an external cooler 18 and is then delivered through the shell to the top of the motor rotor 24 where most of it is flung radially outwardly within the confined space provided by the cap 50 which channels the flow of most of the oil around the top of the stator 26 and then out to a multiplicity of holes 52 to flow down to the sump and provide further cooling of the motor and compressor. Part of the oil descends internally of the motor to the annular chamber 58 to provide oil cooling of the lower part of the motor, with this oil exiting through vent hole 62 also to the sump. Suction gas with entrained oil and liquid refrigerant therein is delivered to an oil separator 68 from which the suction gas passes by a confined path in pipe 66 to the suction plenum 64 and the separated oil drops from the separator to the sump. By providing the oil cooling of the parts, the suction gas is not used for cooling purposes and accordingly increase in superheat is substantially avoided in the passage of the suction gas through the shell to the suction plenum 64.

  6. Development of a low noise 10 K J-T refrigeration system

    NASA Astrophysics Data System (ADS)

    Little, William A.

    1987-02-01

    This report summarizes work on the development of a low noise Joule-Thomson, microminiature refrigeration system, designed for 10 K operation. Two events have occurred since the last report which have had an important influence on the confirmation through a series of experimental measurements of the remarkable cooling power at 80 K to 90 K of the nitrogen-hydrocarbon gas mixtures discussed briefly in the previous report. These experiments confirmed that these mixtures could give a refrigeration an order of magnitude greater than that attainable with argon or nitrogen at the same input pressures. In addition, it was recognized that this high efficiency allowed one to use a heat exchanger of substantially smaller surface area and a compressor designed for operation at much lower pressures. This lower pressure operation would greatly reduce the wear of the piston seals and thereby prolong the life of the system. It was also discovered in the course of these measurements that the use of the gas mixtures resulted in virtually clog-free operation of the refrigerators.

  7. Near azeotropic mixture substitute for dichlorodifluoromethane

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1996-01-01

    The present invention comprises a refrigerant mixture having two halocarbon components. The first component is present in a mole fraction of about 0.7 to less than 1.0 while the second component is present in a mole fraction of more than 0.0 to about 0.3. The first component is CH.sub.2 FCF.sub.3. The second component can be CHClFCF.sub.3, CH.sub.3 CClF.sub.2, a mixture of CHClFCF.sub.3 and CH.sub.3 CClF.sub.2, a mixture of CHF.sub.2 CH.sub.3 and CHClFCF.sub.3, a mixture of CHF.sub.2 CH.sub.3 and CH.sub.3 CClF.sub.2, or a mixture of CHClFCF.sub.3, CH.sub.3 CClF.sub.2 and CHF.sub.2 CH.sub.3. The preferred embodiment of this invention comprises about 0.7 to less than 1.0 mole fraction CH.sub.2 FCF.sub.3, and more than 0.0 to about 0.3 mole fraction of a mixture of CHClFCF.sub.3 and CH.sub.3 CClF.sub.2. The most preferred embodiment of this invention comprises about 0.7 to less than 1.0 mole fraction CH.sub.2 FCF.sub.3 and more than 0.0 to about 0.3 mole fraction CH.sub.3 CClF.sub.2. The resulting refrigerant has a vapor pressure close to-that of CF.sub.2 Cl.sub.2, a nearly constant vapor pressure with evaporation, and is substantially less damaging to the Earth's ozone layer than CF.sub.2 Cl.sub.2.

  8. Modeling of secondary loop refrigeration systems in supermarket applications

    Microsoft Academic Search

    William Travis Horton

    2002-01-01

    Today's supermarket refrigeration systems predominantly use the direct expansion vapor compression cycle to provide cooling to refrigeration and freezer display cases. Next to the environmental concerns of global warming and ozone depletion associated with leakage of the currently used CFC and HCFC refrigerants from these systems, there is also a concern for the rising cost of purchasing suitable alternative refrigerants

  9. 1st TECCS meeting, 26th April 2007 Adsorption Refrigeration

    E-print Network

    Davies, Christopher

    cycles for: Heat pumps Refrigerators Air conditioning Driven by heat from: Fossil fuels Bio fuels Waste1st TECCS meeting, 26th April 2007 Adsorption Refrigeration Research at Warwick Prof. R.E. Critoph refrigerant into a solid as the basis of a refrigeration cycle. It all started with Faraday in 1821... #12;1st

  10. SEARCHING FOR NEW ALTERNATIVE REFRIGERANT FOR AUTOMOBILE AIR - CONDITIONING

    Microsoft Academic Search

    Andrzej Skrzyniowski; Dorota Skrzyniowska

    Due to high consumer acceptance of automobile air conditioning systems, the discussion of the effects of refrigerants on global warming is becoming more important to an environmentally aware public. The CFC problem created searching for new alternative refrigerant for automobile air conditioning. Natural refrigerant - CO2 is a near idea of refrigerant which can be used in automobile air- conditioning

  11. Combined marine refrigerating and air conditioning system using thermal storage

    Microsoft Academic Search

    Alston

    1993-01-01

    A refrigerating and air conditioning system is described for a marine vessel which comprises: (a) a single compressor means to create a pressure differential in the refrigerant gas, and (b) a water cooled condenser to cause the pressurized refrigerant gas to liquify, and (c) a receiver to store liquidized refrigerant gas, and (d) a heat transfer means to transfer heat

  12. Energy performance of supermarket refrigeration and air conditioning integrated systems

    Microsoft Academic Search

    Luca Cecchinato; Marco Corradi; Silvia Minetto

    2010-01-01

    The electricity consumption for air conditioning and refrigerated cases in large supermarkets represents a substantial share of the total electricity consumption. The energy efficiency of supermarkets can be improved by optimising components design, recovering thermal and refrigerating energy, adopting innovative technology solutions, integrating the HVAC system with medium temperature and low-temperature refrigeration plants and, finally, reducing thermal loads on refrigerated

  13. Dual-circuit, multiple-effect refrigeration system and method

    DOEpatents

    DeVault, Robert C. (Knoxville, TN)

    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.

  14. 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.

  15. Room Temperature Magnetic Refrigerator Using Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Naoki, Hirano

    2003-03-01

    This paper describes experimental results of a magnetic refrigerator which is operated at room temperature region. The feature of this study is that a permanent magnet is used to make a magnetic field. A magnetic refrigerator has been expected as an Eco-friendly refrigerator which does not use any CFCs (chlorofluorocarbons) or alternatives and as a high efficient refrigerator. But one of the technical issues for a magnetic refrigerator is that it needs a high magnetic field. A superconducting magnet has been often used to generate a high magnetic field up to about 5 T. It reduces a efficiency and increases the size of a magnetic refrigerator. In this study, a permanent magnet was adopted to generate a magnetic field of 0.6 T and confirmed the refrigeration at room temperature region with such a weak magnetic field. The magnetic refrigerator mainly consisted of two sets of FeNdB magnet with iron yokes, four sets of magnetic material vessels with driving system and cooling system of materials. Gd_1-XDyX were used as magnetic materials and they were filled in magnetic material vessels. Three kinds of materials such as Gd_1-XDyX (x = 0.11, 0.13, 0.16) were used and their Curie temperatures were 10 ^oC, 5 ^oC and 0 ^oC respectively. The magnetic material vessels were reciprocated by the driving system to apply high (0.6 T) and low (0 T) magnetic field to the materials alternatively. Each vessel had two pipes which were connected to the cooling system. The cooling system flowed alcohol doped water alternatively. The alternative magnetic field and water flow in 0.25 Hz made an active magnetic refrigeration cycle. In this configuration, the maximum temperature difference of 12 ^oC was obtained and the lowest temperature of -1 ^oC was achieved.

  16. Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC database). Published Search

    SciTech Connect

    NONE

    1995-01-01

    The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains a minimum of 118 citations and includes a subject term index and title list.)

  17. Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC database). Published Search

    SciTech Connect

    Not Available

    1994-02-01

    The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains a minimum of 107 citations and includes a subject term index and title list.)

  18. Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC database). Published Search

    SciTech Connect

    NONE

    1995-12-01

    The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  19. Improved Regenerative Sorbent-Compressor Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1992-01-01

    Conceptual regenerative sorbent-compressor refrigerator attains regeneration efficiency and, therefore, overall power efficiency and performance greater than conventional refrigerators. Includes two fluid loops. In one, CH2FCF3 (R134a) ciculates by physical adsorption and desorption in four activated-charcoal sorption compressors. In other, liquid or gas coolant circulated by pump. Wave of regenerative heating and cooling propagates cyclically like peristatic wave among sorption compressors and associated heat exchangers. Powered by electricity, oil, gas, solar heat, or waste heat. Used as air conditioners, refrigerators, and heat pumps in industrial, home, and automotive applications.

  20. Refrigerant PhaseChange Stirling-Cycle Solar Power Towers

    Microsoft Academic Search

    Dezhong Huang

    2011-01-01

    This paper firstly introduces the principles of Refrigerant Phase-Change Stirling-Cycle solar power towers This heat engines use solar reservoire. When the refrigerant in an engine cylinder absorbs heat from high-temperature heat sources, refrigerant is transformed from liquid to gas and the volume of the refrigerant expands to drive the piston apply work. When the refrigerant releases heat to low-temperature sources,

  1. Compatibility of refrigerants and lubricants with engineering plastics

    SciTech Connect

    Cavestri, R.C.

    1993-01-01

    Seven oil immersion studies were completed at both 20 and 60C. Test bars used in this study fall within the manufacturer specification limits of physical consistency and integrity. Refrigerant Immersion studies at ambient and 60C are also complete. Equilibrium refrigerant gas solubilities of the 32 ISO VG branched acid polyolester with all ten refrigerants have been determined and completed at 20C. Finally, the thermal aging of plastics at constant refrigerant pressure exposure with seventeen refrigerant lubricant combinations have been completed.

  2. Refrigeration cycle operable by low thermal potential energy sources

    Microsoft Academic Search

    I. Borde; Y. Yaron

    1986-01-01

    An absorption-refrigeration system is described which consists of: a volatile refrigerant selected from the group consisting of fluoro- and fluoro-chloro-hydrocarbons; an absorbent consisting essentially of an organic polar solvent possessing a strong chemical affinity for the refrigerant; means, comprising a generator having a solution of the refrigerant in the solvent therein for vaporizing the refrigerant from the solution by heat

  3. New magnetic refrigeration materials for the liquefaction of hydrogen

    SciTech Connect

    Gschneidner, K.A.; Takeya, H.; Moorman, J.O.; Pecharsky, V.K.; Malik, S.K. [Iowa State Univ., Ames, IA (United States); Zimm, C.B. [Astronautics Corporation of America, Madison, WI (United States)

    1994-12-31

    Five heavy lanthanide ferromagnetic intermetallic compounds were studied as potential magnetic refrigerants for the liquefaction of hydrogen gas. (Dy{sub 0.5}Er{sub 0.5})Al{sub 2} and TbNi{sub 2} appear to be better refrigerants than GdPd for a Joule-Brayton cycle refrigerator, while (Gd{sub 0.54}Er{sub 0.46})AlNi seems to be a suitable refrigerant for an Ericsson cycle refrigerator.

  4. Main characteristics of a Brayton refrigeration cycle of paramagnetic salt

    NASA Astrophysics Data System (ADS)

    Chen, Lixuan; Yan, Zijun

    1994-02-01

    The characteristics of a magnetic Brayton refrigeration cycle are investigated on the basis of the general equation of state of a simple paramagnetic salt. The refrigeration heat and the coefficient of performance of the magnetic Brayton refrigeration cycle are derived, and the effect of regeneration on the performance is discussed. It is expounded that the magnetic Brayton refrigeration cycle possesses both advantages of the magnetic Ericsson and the magnetic Carnot refrigeration cycles.

  5. Bearing construction for refrigeration compresssor

    DOEpatents

    Middleton, Marc G. (Wyoming, MI); Nelson, Richard T. (Worthington, OH)

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  6. Ferroelectric Stirling-Cycle Refrigerator

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr. (Inventor); Hellbaum, Richard F. (Inventor); Rohrbach, Wayne W. (Inventor)

    1999-01-01

    A Stirling-cycle refrigerator has a three-pump configuration and pumping sequence, in which one pump serves as a compressor. one pump serves as an expander, and one pump serves as a displacer. The pumps are ferroelectrically actuated diaphragm pumps which are coordinated by synchronizing the ferroelectric-actuator voltages in such a way that the net effect of the displacer is to reduce the deleterious effect of dead space; that is, to circulate a greater fraction of the working fluid through the heat exchangers than would be possible by use of the compressor and expander alone. In addition. the displacer can be controlled separately to make the flow of working fluid in the heat exchangers turbulent (to increase the rate of transfer of heat at the cost of greater resistance to flow) or laminar (to decrease the resistance to flow at the cost of a lower heat-transfer rate).

  7. Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration

    SciTech Connect

    Bansal, Pradeep [ORNL; Vineyard, Edward Allan [ORNL; Abdelaziz, Omar [ORNL

    2012-01-01

    This paper presents a review of the next generation not-in-kind technologies to replace conventional vapor compression refrigeration technology for household applications. Such technologies are sought to provide energy savings or other environmental benefits for space conditioning, water heating and refrigeration for domestic use. These alternative technologies include: thermoacoustic refrigeration, thermoelectric refrigeration, thermotunneling, magnetic refrigeration, Stirling cycle refrigeration, pulse tube refrigeration, Malone cycle refrigeration, absorption refrigeration, adsorption refrigeration, and compressor driven metal hydride heat pumps. Furthermore, heat pump water heating and integrated heat pump systems are also discussed due to their significant energy saving potential for water heating and space conditioning in households. The paper provides a snapshot of the future R&D needs for each of the technologies along with the associated barriers. Both thermoelectric and magnetic technologies look relatively attractive due to recent developments in the materials and prototypes being manufactured.

  8. Purification and Liquefacttion of Neon Using a Helium Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Boeck, S.

    2010-04-01

    The cryogenic plant developed by Linde Kryotechnik is used to extract neon out of a crude gas flow coming from an air separation plant. The crude gas is cooled down by a two stage helium refrigeration process using the Linde Kryotechnik dynamic gas bearing turbines. After the first cooling stage, nitrogen is liquefied and separated from the crude gas. The Cryogenic adsorbers located at a temperature level below 80 K clean the crude gas from remaining nitrogen traces before the neon-helium mixture enters the final cooling stage. In the second cooling stage neon is liquefied and separated from the helium. The final product quality will be achieved within a rectification column at low pressure level.

  9. Lubrication characteristics of a rotary compressor used for refrigeration and air-conditioning systems (the influence of alternative refrigerants)

    Microsoft Academic Search

    Ihn-Sung Cho; Jae-Youn Jung

    2010-01-01

    The rolling piston type rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness\\u000a and high-speed characteristics. However, it is necessary to develop alternative refrigerants that can guarantee environmental\\u000a protection. In addition, advanced refrigerant compressors must be further developed to overcome the compatibility problems\\u000a inherent in refrigeration and air-conditioning systems. The refrigerant compressor is the

  10. Simulation of the Energy Saver refrigeration system

    SciTech Connect

    Barton, H.R. Jr.; Nicholls, J.E.; Mulholland, G.T.

    1981-10-01

    The helium refrigeration for the Energy Saver is supplied by a Central Helium Liquefier and 24 Satellite Refrigerators installed over a 1-1/4 square mile area. An interactive, software simulator has been developed to calculate the refrigeration available from the cryogenic system over a wide range of operating conditions. The refrigeration system simulator incorporates models of the components which have been developed to quantitatively describe changes in system performance. The simulator output is presented in a real-time display which has been used to search for the optimal operating conditions of the Satellite-Central system, to examine the effect of an extended range of operating parameters and to identify equipment modifications which would improve the system performance.

  11. Three-terminal quantum-dot refrigerators

    NASA Astrophysics Data System (ADS)

    Zhang, Yanchao; Lin, Guoxing; Chen, Jincan

    2015-05-01

    Based on two capacitively coupled quantum dots in the Coulomb-blockade regime, a model of three-terminal quantum-dot refrigerators is proposed. With the help of the master equation, the transport properties of steady-state charge current and energy flow between two quantum dots and thermal reservoirs are revealed. It is expounded that such a structure can be used to construct a refrigerator by controlling the voltage bias and temperature ratio. The thermodynamic performance characteristics of the refrigerator are analyzed, including the cooling power, coefficient of performance (COP), maximum cooling power, and maximum COP. Moreover, the optimal regions of main performance parameters are determined. The influence of dissipative tunnel processes on the optimal performance is discussed in detail. Finally, the performance characteristics of the refrigerators operated in two different cases are compared.

  12. Defrost Temperature Termination in Supermarket Refrigeration Systems

    SciTech Connect

    Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

    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, 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.

  13. Refrigeration system having standing wave compressor

    DOEpatents

    Lucas, Timothy S. (Glen Allen, VA)

    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.

  14. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...refrigeration system must: (1) Have a heat exchanger with an excess capacity...required capacity; or (2) A standby heat exchanger. (d) Where cooling...other. (f) The pressure of the heat transfer fluid in each cooling coil in a...

  15. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...refrigeration system must: (1) Have a heat exchanger with an excess capacity...required capacity; or (2) A standby heat exchanger. (d) Where cooling...other. (f) The pressure of the heat transfer fluid in each cooling coil in a...

  16. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...refrigeration system must: (1) Have a heat exchanger with an excess capacity...required capacity; or (2) A standby heat exchanger. (d) Where cooling...other. (f) The pressure of the heat transfer fluid in each cooling coil in a...

  17. Intra-molecular refrigeration in enzymes

    E-print Network

    Hans J. Briegel; Sandu Popescu

    2009-12-14

    We present a simple mechanism for intra-molecular refrigeration, where parts of a molecule are actively cooled below the environmental temperature. We discuss the potential role and applications of such a mechanism in biology, in particular in enzymatic reactions.

  18. Design of Industrial Process Refrigeration Systems 

    E-print Network

    Witherell, W. D.

    1987-01-01

    When considering electric driven refrigeration compressors, proper integration with the process may result in reduced power consumption. However, the total utility situation must be considered when evaluating the compressor driver. Conversion from...

  19. Residential Refrigerator Recycling Ninth Year Retention Study

    E-print Network

    Residential Refrigerator Recycling Ninth Year Retention Study Study ID Nos. 546B, 563 Prepared RECYCLING PROGRAMS Study ID Nos. 546B and 563 Prepared for Southern California Edison Rosemead, California

  20. 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.

  1. Thermal modeling for an optical refrigerator

    NASA Astrophysics Data System (ADS)

    Martin, K. W.; Schomacker, J.; Fraser, T.; Dodson, C.

    2015-03-01

    Optical refrigeration is currently the only completely solid state cooling method capable of reaching cryogenic temperatures from room temperature. Optical cooling utilizing Yb:YLF as the refrigerant crystal has resulted in temperatures lower than 123K measured via a fluorescence thermometry technique. However, to be useful as a refrigerator this cooling crystal must be attached to a sensor or other payload. The phenomenology behind laser cooling, known as anti-Stokes fluorescence, has a relatively low efficiency which makes the system level optimization and limitation of parasitic losses imperative. We propose a variety of potential designs for a final optical refrigerator, enclosure and thermal link; calculate conductive and radiative losses, and estimate direct fluorescence reabsorption. Our simulated designs show losses between 60 and 255 mW, depending on geometry and enclosure choice, with a lower bound as low as 23 mW.

  2. Refrigeration system for W7-X

    Microsoft Academic Search

    Y. Bozhko; F. Schauer

    2003-01-01

    The refrigeration system for the W7-X superconducting magnet and the divertor cryo-vacuum pumps is presented. In total, five main helium cooling circuits have to be supplied by the refrigerator---four for the magnet including auxiliary equipment like support structure, thermal shield and current leads, and one for the cryo-pumps. For the shields of the latter, an additional LN2---cooling circuit is required.

  3. Acute lung injury following refrigeration coil deicing.

    PubMed

    McKeown, Nathanael J; Burton, Brent T

    2012-03-01

    We report a case of a worker who developed ALI requiring mechanical ventilatory support after attempting to melt ice condensate by applying the flame of an oxy-acetylene torch to refrigeration coils charged with a halocarbon refrigerant in a closed environment. A discussion of possible etiologies are discussed, including phosgene, carbonyl fluoride, and nitrogen oxides. Primary prevention with adequate respiratory protection is recommended whenever deicing is performed in a closed space environment. PMID:22372791

  4. 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.

  5. Combined cold compressor/ejector helium refrigerator

    DOEpatents

    Brown, D.P.

    1984-06-05

    A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

  6. Retrofit cogeneration system increases refrigeration capacity

    SciTech Connect

    Amberger, R.F. (Modern Energy Technology Corp., Rochester, NY (United States)); DeFrees, J.A. (Fleming Group, Syracuse, NY (United States))

    1993-04-01

    This article describes a retrofit cogeneration systems for increasing refrigeration capacity at a milk processing plant in Queens, New York. The natural gas/ammonia cogeneration and subcooling systems reduce CO[sub 2] emissions and provide cost and energy savings. The topics of the article include the innovative aspects, computer modeling for system analysis, analysis technique, system configuration, refrigeration loads, operations and maintenance, cost effectiveness and environmental benefits.

  7. Efficient electrochemical refrigeration power plant using natural gas with ?100% CO2 capture

    NASA Astrophysics Data System (ADS)

    Al-musleh, Easa I.; Mallapragada, Dharik S.; Agrawal, Rakesh

    2015-01-01

    We propose an efficient Natural Gas (NG) based Solid Oxide Fuel Cell (SOFC) power plant equipped with ?100% CO2 capture. The power plant uses a unique refrigeration based process to capture and liquefy CO2 from the SOFC exhaust. The capture of CO2 is carried out via condensation and purification using two rectifying columns operating at different pressures. The uncondensed gas mixture, comprising of relatively high purity unconverted fuel, is recycled to the SOFC and found to boost the power generation of the SOFC by 22%, when compared to a stand alone SOFC. If Liquefied Natural Gas (LNG) is available at the plant gate, then the refrigeration available from its evaporation is used for CO2 Capture and Liquefaction (CO2CL). If NG is utilized, then a Mixed Refrigerant (MR) vapor compression cycle is utilized for CO2CL. Alternatively, the necessary refrigeration can be supplied by evaporating the captured liquid CO2 at a lower pressure, which is then compressed to supercritical pressures for pipeline transportation. From rigorous simulations, the power generation efficiency of the proposed processes is found to be 70-76% based on lower heating value (LHV). The benefit of the proposed processes is evident when the efficiency of 73% for a conventional SOFC-Gas turbine power plant without CO2 capture is compared with an equivalent efficiency of 71.2% for the proposed process with CO2CL.

  8. Prediction of Heat Transfer Coefficient for Refrigerant With Oil Contained in Horizontal Evaporator Tuvbes

    NASA Astrophysics Data System (ADS)

    Matsunaga, Takeshi; Yoshida, Suguru

    A method which is generally applicable to predict the axially local (circumferentially averaged) heat transfer coefficient for refrigerant with oil contained flowing in horizontal evaporator tubes was developed by modifying a prediction method for pure refrigerants. The dimensionless correlation for an annular flow regime takes account of the influence of oil on an improvement or a reduction in the heat transfer, in addition to the change of the properties due to the addition of oil. For a separated flow regime, the correlations of the average heat transfer coefficients in the top part and the bottom part and their boundary angle were developed by modifying each correlation for pure refrigerants. The circumferentially averaged heat transfer coefficient for the separated flow regime can be obtained by using the solution of the steady heat conduction equation in the tube wall, to which the values calculated from the above correlations are applied as the boundary conditions at the inside surface of the tube. Which flow regime, annular or separated, prevails can be determined by the correlation of the boundary angle. The present prediction method was confirmed to be applicable to various kinds of refrigerant-oil mixture.

  9. Vaccine refrigeration technologies and power sources

    SciTech Connect

    Rovero, C.; Waddle, D. (Oak Ridge Associated Universities, Inc., TN (USA); Oak Ridge National Lab., TN (USA))

    1989-10-01

    Adequate refrigeration of vaccines is an essential component of the worldwide child immunization effort sponsored cooperatively by such development assistance agencies as the World Health Organization, the United Nations Children's Fund, and the US Agency for International Development (AID), and by developing countries. Unfortunately, the areas in most urgent need of effective immunization programs are often far from reliable refrigerated storage facilities or energy services. Selection of an appropriate energy supply and/or refrigeration technology has been seen as a limiting factor in effective immunization programs. In response to this problem, this document has been prepared to assist in the selection of reliable and affordable refrigeration systems. It provides information on refrigeration technologies and energy sources currently employed in the vaccine cold chain and discusses possible responses to a variety of energy-related problems, including intermittent or unreliable electric service, and unreliable supply, unavailability, or poor quality of fuels for refrigerators in health centers not served by the electric power grid. 18 refs., 5 figs.

  10. Initial adsorption of water molecule on HfC and TaC (0 0 1) surfaces from density-functional study

    NASA Astrophysics Data System (ADS)

    Liu, Dongliang; Deng, Jianguo; Jin, Yongzhong

    2014-01-01

    We investigated the initial adsorption of molecular water on HfC and TaC (0 0 1) surfaces using first-principles density-functional theory. In our investigation, the revised Perdew-Burke-Ernzerhof functional (RPBE) generalized gradient approach (GGA) was used to treat the exchange and correlation potential. We modeled the (0 0 1) surfaces with (?2 × ?2) R45° supercell. Every supercell contains five atomic planes. Our calculations show that the adsorption energies of H2O are low. The energies are -0.44 eV/molecule and -0.65 eV/molecule on HfC and TaC (0 0 1) surfaces, respectively. On both the (0 0 1) surfaces, molecular water prefers to be adsorbed on top of surface metal atom. However, only the oxygen atom of water molecule is bound with surface metal atom. And the plane of water molecule tends to be parallel to the surfaces. Compared with the oxygen and hydrogen atoms of an isolated water molecule, the oxygen and hydrogen atoms in H2O/HfC (0 0 1) and H2O/TaC (0 0 1) have less negative and positive charges, respectively. Our results show that water molecule is adsorbed molecularly on HfC and TaC (0 0 1) surfaces at initial adsorption stage. Moreover, the interaction of water molecule with the (0 0 1) surfaces is weak. Charge density differences and density of states show that Osbnd Ta bond is slightly stronger than Osbnd Hf bond. Due to the strong Osbnd Ta bond, the oxidation resistance of TaC may stronger than HfC in water vapor atmosphere.

  11. Comparative analysis of CO 2 -based transcritical Rankine cycle and HFC245fa-based subcritical organic Rankine cycle using low-temperature geothermal source

    Microsoft Academic Search

    Tao Guo; HuaiXin Wang; ShengJun Zhang

    2010-01-01

    A detailed thermodynamic and techno-economic comparison is presented for a CO2-based transcritical Rankine cycle and a subcritical organic Rankine cycle (ORC) using HFC245fa (1,1,1,3,3-pentafluoro-propane)\\u000a as the working fluid driven by the low-temperature geothermal source, in order to determine the configuration that presents\\u000a the maximum net power output with a minimum investment. The evaluations of both Rankine cycles have been performed

  12. A Superfluid Pulse Tube Refrigerator Without Moving Parts for Sub-Kelvin Cooling

    NASA Technical Reports Server (NTRS)

    Miller, Franklin K.

    2012-01-01

    A report describes a pulse tube refrigerator that uses a mixture of He-3 and superfluid He-4 to cool to temperatures below 300 mK, while rejecting heat at temperatures up to 1.7 K. The refrigerator is driven by a novel thermodynamically reversible pump that is capable of pumping the He-3 He-4 mixture without the need for moving parts. The refrigerator consists of a reversible thermal magnetic pump module, two warm heat exchangers, a recuperative heat exchanger, two cold heat exchangers, two pulse tubes, and an orifice. It is two superfluid pulse tubes that run 180 out of phase. All components of this machine except the reversible thermal pump have been demonstrated at least as proof-of-concept physical models in previous superfluid Stirling cycle machines. The pump consists of two canisters packed with pieces of gadolinium gallium garnet (GGG). The canisters are connected by a superleak (a porous piece of VYCOR glass). A superconducting magnetic coil surrounds each of the canisters.

  13. 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 ...

  14. Challenges in recovery and recycling of refrigerants from Indian refrigeration and air-conditioning service sector

    Microsoft Academic Search

    Sukumar Devotta; Saroja Asthana; Rahul Joshi

    2004-01-01

    India is a large producer and user of chlorofluorocarbons (CFCs) in the refrigeration and air-conditioning (RAC) sector. Government of India has taken several steps to restrict the production and consumption of CFCs. Refrigerant conservation through recovery, recycling (R&R) and reclamation is one way of reducing emissions and encouraging timely phase out of CFCs in developing countries. CFC recovery, recycling and

  15. Global warming impacts of ozone-safe refrigerants and refrigeration, heating, and air-conditioning technologies

    Microsoft Academic Search

    S. Fischer; J. Sand; V. Baxter

    1997-01-01

    International agreements mandate the phase-out of many chlorine containing compounds that are used as the working fluid in refrigeration, air-conditioning, and heating equipment. Many of the chemical compounds that have been proposed, and are being used in place of the class of refrigerants eliminated by the Montreal Protocol are now being questioned because of their possible contributions to global warming.

  16. 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 Program. Discussion topics include requirements for developing a refrigerant management plan and establishing priorities for cost-effective compliance with the CAAA, as well as ways in which employees can be empowered to develop a comprehensive refrigerant management plan. The result of this employee empowerment was a cooperative labor-management effort that is beneficial for Y-12, DOE, and the environment.

  17. 77 FR 3559 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-25

    ...Conservation Program for Consumer Products: Test Procedures for Refrigerators, Refrigerator-Freezers...rulemaking amends the interim final rule for test procedures for refrigerators, refrigerator-freezers...December 16, 2010. Specifically, it amends test procedures at subpart B, appendices...

  18. LOW-GLOBAL-WARMING CHEMICALS AND REFRIGERANT TECHNOLOGIES (ATMOSPHERIC PROTECTION BRANCH, APPCD, NRMRL)

    EPA Science Inventory

    The Atmospheric Protection Branch's Refrigeration Applications Laboratory has the capability to test several types of refrigeration equipment with various refrigerants. Refrigeration compressors are tested according to the ANSI/ASHRAE 23-1993 Test Standard and under various oper...

  19. saturated liquid. The region above the vapor line is superheated vapor; that below the lower line is subcooled liquid. The region enclosed by the pair represents a mixture of liquid and

    E-print Network

    Oak Ridge National Laboratory

    DIAGRAM OF A MIXTURE A convenient tool to assist in cycle calculations of refrigerating systems is a pressure- enthalpy diagram displaying the saturated-liquid and saturated-vapor lines, as well-114. The first noticeable difference between Figure 3 and a p-h diagram for a single refrigerant

  20. Quantum Heat Engines and Refrigerators: Continuous Devices

    NASA Astrophysics Data System (ADS)

    Kosloff, Ronnie; Levy, Amikam

    2014-04-01

    Quantum thermodynamics supplies a consistent description of quantum heat engines and refrigerators up to a single few-level system coupled to the environment. Once the environment is split into three (a hot, cold, and work reservoir), a heat engine can operate. The device converts the positive gain into power, with the gain obtained from population inversion between the components of the device. Reversing the operation transforms the device into a quantum refrigerator. The quantum tricycle, a device connected by three external leads to three heat reservoirs, is used as a template for engines and refrigerators. The equation of motion for the heat currents and power can be derived from first principles. Only a global description of the coupling of the device to the reservoirs is consistent with the first and second laws of thermodynamics. Optimization of the devices leads to a balanced set of parameters in which the couplings to the three reservoirs are of the same order and the external driving field is in resonance. When analyzing refrigerators, one needs to devote special attention to a dynamical version of the third law of thermodynamics. Bounds on the rate of cooling when Tc?0 are obtained by optimizing the cooling current. All refrigerators as Tc?0 show universal behavior. The dynamical version of the third law imposes restrictions on the scaling as Tc?0 of the relaxation rate γc and heat capacity cV of the cold bath.

  1. Magnetocaloric refrigeration. Research and development report

    SciTech Connect

    Green, G.; Patton, G.; Stevens, J.; Humphrey, J.

    1987-03-01

    The magnetocaloric refrigerator uses the adiabatic temperature response of ferromagnetic materials (rare-earth metals) in a high magnetic field. A mathematical model of a reciprocating magnetic refrigerator having an active element of a rare-earth metal predicted that a 60-K temperature span could be achieved. Based on the model's results, an experimental refrigerator was fabricated and the thermal characteristics of an active regenerator in a reciprocating apparatus were measured. The active material was gadolinium, which has a Curie temperature of 293 K and was formed into an embossed ribbon geometry. Significant regeneration in the magnetic material was observed, and a 50-K temperature span was achieved. A cold end temperature of 246 K was measured. The results indicated that the active regeneration concept can successfully produce magnetocaloric refrigeration at temperatures near the Curie temperature of the material, and the measured temperature span verified the mathematical model developed to describe the process. Further, if the active magnetic element were a combination of several rare-earth metals having significant magnetocaloric effects at decreasing temperatures, the possibility exists for producing a single-stage magnetic refrigerator that could operate over a very large temperature span.

  2. Fully portable, highly flexible dilution refrigerator systems for neutron scattering

    E-print Network

    Boyer, Edmond

    775 Fully portable, highly flexible dilution refrigerator systems for neutron scattering P. A systems developed specifically for neutron scattering environ- ments. The refrigerators are completely relatively recently however, the lowest temperatures available in almost all neutron scattering laboratories

  3. Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems

    E-print Network

    Barrer, P. J.; Jones, S. M.

    This paper presents case studies of two moderately sized ammonia refrigeration systems retrofitted for floating head pressure control. It also presents a parametric analysis to assist in selecting appropriate pressures in an ammonia refrigeration...

  4. Microcomputer Software for Refrigerant Property and Cycle Analysis Calculations 

    E-print Network

    Bierschenk, J. L.; Strohl, S. T.; Schmidt, P. S.

    1985-01-01

    A microcomputer program entitled REFRIG has been developed to determine the thermodynamic properties of common refrigerants and to analyze vapor-compression refrigeration cycles. This paper describes the theoretical basis for property determination...

  5. CONTROL OF HYDROCARBON EMISSIONS FROM GASOLINE LOADING BY REFRIGERATION SYSTEMS

    EPA Science Inventory

    The report gives results of a study of the capabilities of refrigeration systems, operated at three temperatures, to control volatile organic compound (VOC) emissions from truck loading at bulk gasoline terminals. Achievable VOC emission rates were calculated for refrigeration sy...

  6. Thermoelectric refrigerator having improved temperature-stabilization means

    SciTech Connect

    Falco, C.M.

    1981-07-29

    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.

  7. Optimal Design Refrigeration System for a Mucilage Glue Fiber Factory 

    E-print Network

    Tan, C.; Liu, J.; Tang, F.; Liu, Y.

    2006-01-01

    In a mucilage glue fiber factory, the design of the refrigeration system takes into account the characteristics of mucilage glue fiber production and fully uses the refrigeration compressor heat to economize energy and reduce the production cost...

  8. 46 CFR 58.20-20 - Refrigeration piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Refrigeration...primary refrigerant, brine, or fluid used, and shall be of such chemical and physical properties as to remain ductile at the...

  9. Analysis of magnetic refrigeration for air conditioning applications

    Microsoft Academic Search

    1979-01-01

    The report presents an analysis of the principles of magnetic refrigeration with application to air conditioning. A comparison with conventional evaporation-condensation gas cycle devices is presented. Conclusions concerning the applicability of magnetic refrigeration to air conditioning are made.

  10. 49 CFR 179.102-1 - Carbon dioxide, refrigerated liquid.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...dioxide, refrigerated liquid. (a) Tank cars used to transport carbon dioxide, refrigerated liquid must comply with the following... (1) All plates for tank, manway nozzle and anchorage...section of the printed volume and at...

  11. 49 CFR 179.102-1 - Carbon dioxide, refrigerated liquid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...dioxide, refrigerated liquid. (a) Tank cars used to transport carbon dioxide, refrigerated liquid must comply with the following... (1) All plates for tank, manway nozzle and anchorage...section of the printed volume and at...

  12. Radiation properties and sound quality characteristics of refrigerator noise

    NASA Astrophysics Data System (ADS)

    Jeon, Jin Yong; Jeong, Jeong Ho; You, Jin

    2005-09-01

    The characteristics of refrigerator noise in an anechoic chamber and in an actual environment were investigated. In order to predict the noise propagation in real apartment house, room acoustic simulations and measurements using different types of refrigerators were conducted. The sound-pressure level of the refrigerator noise in the real living room was much higher than in the anechoic chamber. In addition, an allowable sound-pressure level for refrigerator noise was determined by auditory experiments. For the stimuli of auditory experiments, the dry source of refrigerator noise was presented using a loud speaker at the position of the refrigerator. When the result of the subjective evaluation was at the level 2 (the noise rarely aware but comfortable), in which sound pressure level was about 25 dB(A), 95% of people were satisfied with the refrigerator noise. A semantic differential test using various adjectives was also conducted to evaluate the sound quality of refrigerator noise.

  13. Thermodynamic Comparison of Two Types of Stirling Refrigerators

    Microsoft Academic Search

    Z. H. Wu; E. C. Luo; W. Dai; S. F. Li

    The pulse-tube type of two-piston Stirling refrigerator can improve reliability by moving the expansion piston from the cold end to the ambient temperature end. More recently, the thermo- acoustic-Stirling refrigerator further improves reliability by eliminating the expansion piston. The thermoacoustic-Stirling refrigerator uses a traveling-wave loop to achieve the Stirling cycle. Both refrigerators have a pulse tube. By means of thermodynamic

  14. Microcomputer Software for Refrigerant Property and Cycle Analysis Calculations

    E-print Network

    Bierschenk, J. L.; Strohl, S. T.; Schmidt, P. S.

    the properties of temperature, pressure, enthalpy, entropy, and specific volume at all state points in a refrigeration cycle for any of the 11 refrigerants. In addition, RBPRIG computes coefficients of performance for both the refrigeration and the heat pump.... This approximation is used in determining sub cooled specific volume, internal energy, and entropy. Sub-cooled enthalpy is corrected for the increase in pressure above saturation by the following: Refrigeration Cycle Analysis In addition to the property determi...

  15. Analysis of magnetic refrigerators with external regeneration

    SciTech Connect

    Overton, W.C. Jr.; Barclay, J.A.

    1986-01-01

    The central idea of the magnetic refrigeration systems analyzed in this paper is that of a MR having a regenerator composed of an integral number of separate stages but having only a single magnetic stage. In principle, each stage is thermally isolated from the others, but the stages are accessed by a manifold and valve system which allows gas to flow between the MM and the individual stages. The concept therefore is distinctly unlike that of the unusual continuous regenerator of gas refrigerators. Although a small amount of gas in the manifold is responsible for the actual transfer of heat between elements of the REGMR, it is clear from the cycle description in the caption of Fig. 1 that the fixed mass of the MM is analogous to a fixed mass of a working fluid in a gas refrigerator or engine. Both, in effect, are carried thermally through all parts of their respective systems.

  16. Method and apparatus for refrigerant recovery

    SciTech Connect

    Sevrain, C.J.; Lambert, B.C.

    1993-08-17

    An apparatus is described for recovering refrigerant from a system, the apparatus comprising: a vane pump, the vane pump including a central hub having a plurality of blades extending therefrom, the hub and blades being mounted for rotary motion in a chamber defined by a housing, the vane pump including an inlet and an outlet; a motor, the motor being coupled to the hub of the vane pump for imparting rotary motion thereto; a conduit coupling the inlet of the vane pump to the system; a phase sensor positioned to determine the phase of the refrigerant passing from the system to the pump, the sensor producing an output signal corresponding thereto; and pump control means coupled to the sensor and serving to change the capacity of the pump depending on whether the sensor senses the refrigerant is in gas or liquid phase.

  17. Optimal performance of endoreversible quantum refrigerators.

    PubMed

    Correa, Luis A; Palao, José P; Adesso, Gerardo; Alonso, Daniel

    2014-12-01

    The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results that are model independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for any endoreversible quantum refrigerator. At striking variance with the universality of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics. PMID:25615061

  18. An adiabatic demagnetization refrigerator for SIRTF

    SciTech Connect

    Timbie, P.T.; Bernstein, G.M.; Richards, P.L.

    1989-02-01

    An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the Multiband Imaging Photometer of the Space Infrared Telescope Facility (SIRTF). The authors have built one such refrigerator which employs a ferric ammonium alum salt pill suspended by nylon threads in a 3 Tesla solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is <0.5 ..mu..W. The system has a hold time at 0.1 /sup 0/K of >12 hours. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built as a SIRTF prototype to fly on a balloon-borne telescope. It will employ a ferromagnetic shield. The possibility of using high T/sub c/ leads to the superconducting magnet and a solenoid-actuated heat switch are also discussed.

  19. An adiabatic demagnetization refrigerator for SIRTF

    NASA Technical Reports Server (NTRS)

    Timbie, P. T.; Bernstein, G. M.; Richards, P. L.

    1989-01-01

    An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the multiband imaging photometer of the Space Infrared Telescope Facility (SIRTF). One such refrigerator has been built which uses a ferric ammonium alum salt pill suspended by nylon threads in a 3-T solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is less than 0.5 microW. The system has a hold time at 0.1K of more than 12 h. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built at a SIRTF prototype to fly on a ballon-borne telescope. It will use a ferromagnetic shield. The possibility of using a high-Tc solenoid-actuated heat switch is also discussed.

  20. Optimal performance of endoreversible quantum refrigerators

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.; Palao, José P.; Adesso, Gerardo; Alonso, Daniel

    2014-12-01

    The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results that are model independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for any endoreversible quantum refrigerator. At striking variance with the universality of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics.