These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

The Performance Evaluation of Vapor Compression Heat Pump System Using HFC Alternative Refrigerant Mixtures  

NASA Astrophysics Data System (ADS)

This paper deals with an experimental study on the performance evaluation of heat pump systems using HFC alternative refrigerants. The tested heat pump systems are modified from the R22 use to alternative refrigerants. Refrigerant mixtures of R410A, R407C. R32/125 and R32/134a are tested. where R410A and R407C launched into global market recently. Pure refrigerants of R22, R32, R125 and R134a are also tested. The experimental results of alternative refrigerants are evaluated in comparison with the result of R22, and the following are confirmed : (1) the performance of R32 is the highest. (2) adding R125 to R32 and R32/134a results into the deterioration of the performance, (3) the use of counter flow-like heat exchangers for a zeotropic refrigerant mixtures are effective, and (4) in case of R410A. the modification of the compressor to fit operating pressure heightens the performance. The effects of the performance of components on the COP are also analyzed based on the measured thermodynamic states at both ends of components in the system. Then, it is clarified that the most effective factor is irreversibility of compressors and the following is the pressure drop in low pressure side including the evaporator and the suction pipe.

Taira, Shigeharu; Yazima, Ryuzaburo; Tarutani, Isamu; Koyama, Shigeru

2

Improved energy efficiency for CFC domestic refrigerators retrofitted with ozone-friendly HFC134a\\/HC refrigerant mixture  

Microsoft Academic Search

Conversion of CFC12 systems to eco-friendly ones will be a major thrust area for refrigeration sector in the near future. As and when an existing CFC (chlorofluorocarbon) system has to be recharged it is advisable to retrofit the system with an eco-friendly energy efficient refrigerant. Presently two potential substitutes, namely, HFC134a and HC blends are available as drop in substitutes

S. Joseph Sekhar; D. Mohan Lal; S. Renganarayanan

2004-01-01

3

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...

4

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

E-print Network

entering the heat exchanger was monitored using a thermocouple and adjusted by a mechanical thermostat. The heat tape was mounted along an eight foot (2.44 m) section of refrigerant tubing after the evaporation heat exchanger. To prevent heat loss... of the test section was calculated by performing an energy balance of the power input into the heat tape, heat loss through the insulation, and enthalpy at the inlet of the heat tape. The enthalpy at the inlet of the heat tape, which was always subcooled...

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

1994-01-01

5

Evaluation of alternatives for HFC-134a refrigerant in motor vehicle air conditioning  

SciTech Connect

HFC (hydrofluorocarbon)-134a is currently used as the refrigerant in motor vehicle air conditioners. The EPA`s (Environmental Protection Agency`s) NRMRL (National Risk Management Research Laboratory) has evaluated lower global warming alternatives for HFC-134a in motor vehicle air conditioning. Alternative technologies were evaluated. Four pure chemicals and one azeotropic mixture were identified and evaluated as alternative refrigerants for conventional systems, but were found to be unsuitable. The four pure chemicals were HFC-227ca, HFC-227ea, HFC-245cb, and HFE (hydrofluoroether)-143a. The azeotropic mixture was 51.7 weight percent HFC-134 and 48.3 weight percent HFC-245cb. The evaluation process and results are described in this paper.

Jetter, J.J.; Smith, N.D.; Ratanaphruks, K.; Ng, A.S.; Tufts, M.W.

1997-09-01

6

Ozone friendly HFC134a\\/HC mixture compatible with mineral oil in refrigeration system improves energy efficiency of a walk in cooler  

Microsoft Academic Search

In the event of chlorofluorocarbon (CFC) phase out, identifying a long term alternative to meet all our requirements in respect of system performance and service is an important area for research in the refrigeration and air conditioning (RAC) sector. Even though HFC134a and the HC blend (containing 55.2% HC600a and 44.8% HC290) have been reported to be substitutes for CFC12,

S. Joseph Sekhar; K. Senthil Kumar; D. Mohan Lal

2004-01-01

7

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

NASA Astrophysics Data System (ADS)

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.

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

8

New concepts for refrigerant leak detection and mixture measurement  

NASA Astrophysics Data System (ADS)

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.

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

9

PERFORMANCE OF CHLORINE-FREE BINARY ZEOTROPIC REFRIGERANT MIXTURES IN A HEAT PUMP  

EPA Science Inventory

The report gives results of a study that uses a simulation model and an experimental heat pump apparatus with counterflow heat exchangers to show that two hydrofluorocarbon (HFC) refrigerant mixtures, HFC-32/-152a and HFC-32/-134a, may be considered to be replacements for hydroch...

10

HFC-134A and HCFC-22 supermarket refrigeration demonstration and laboratory testing. Phase I. Final report  

SciTech Connect

Aspen Systems and a team of nineteen agencies and industry participants conducted a series of tests to determine the performance of HFC-134a, HCFC-22, and CFC-502 for supermarket application. This effort constitutes the first phase of a larger project aimed at carrying out both laboratory and demonstration tests of the most viable HFC refrigerants and the refrigerants they replace. The results of the Phase I effort are presented in the present report. The second phase of the project has also been completed. It centered on testing all viable HFC replacement refrigerants for CFC-502. These were HFC-507, HFC-404A, and HFC-407A. The latter results are published in the Phase II report for this project. As part of Phase I, a refrigeration rack utilizing a horizontal open drive screw compressor was constructed in our laboratory. This refrigeration rack is a duplicate of one we have installed in a supermarket in Clifton Park, NY.

NONE

1996-04-01

11

Measurement of absorption rates of HFC single and blended refrigerants in POE oils  

SciTech Connect

Thermophysical properties of refrigerant/lubricant mixtures play an important role in refrigeration and air-conditioning system design. Therefore it is important to have a good understanding of the mixture composition in each system component such as the compressor or evaporator. Because the system operation is dynamic the rates of absorption and desorption become significant parameters. In this paper measured absorption rates of alternative refrigerants in polyolester (POE) oils are reported. An effective online mass gain method was designed and constructed to measure the absorption rates and solubility of refrigerants in lubricants. HFC single refrigerants (R-32, R-125, R-134a, and R-143a), and blended refrigerants (R-404A, R-407C, and R-410A) were tested with POE ISO 68 lubricant under various conditions. The experimental results showed that, at room temperature, R-134a is the most soluble in POE ISO 68 oil among all the refrigerants tested at pressures of 239 kPa (20 psig) to 446 kPa (70 psig). Among the blended refrigerants tested, R-407C was found to be the most soluble at room temperature and pressures of 239 kPa and 446 kPa. Experimental solubility data from this new measurement method were compared with data available in the literature. Good agreement between the two indicates the feasibility of the new method employed in this investigation.

Leung, M.; Jotshi, C.K.; Goswami, D.Y.; Shah, D.O.; Gregory, A.

1999-07-01

12

Solubility modeling of refrigerant/lubricant mixtures  

SciTech Connect

A general model for predicting the solubility properties of refrigerant/lubricant mixtures has been developed based on applicable theory for the excess Gibbs energy of non-ideal solutions. In our approach, flexible thermodynamic forms are chosen to describe the properties of both the gas and liquid phases of refrigerant/lubricant mixtures. After an extensive study of models for describing non-ideal liquid effects, the Wohl-suffix equations, which have been extensively utilized in the analysis of hydrocarbon mixtures, have been developed into a general form applicable to mixtures where one component is a POE lubricant. In the present study we have analyzed several POEs where structural and thermophysical property data were available. Data were also collected from several sources on the solubility of refrigerant/lubricant binary pairs. We have developed a computer code (NISC), based on the Wohl model, that predicts dew point or bubble point conditions over a wide range of composition and temperature. Our present analysis covers mixtures containing up to three refrigerant molecules and one lubricant. The present code can be used to analyze the properties of R-410a and R-407c in mixtures with a POE lubricant. Comparisons with other models, such as the Wilson or modified Wilson equations, indicate that the Wohl-suffix equations yield more reliable predictions for HFC/POE mixtures.

Michels, H.H.; Sienel, T.H.

1996-12-31

13

Determination of properties of PVE lubricants with HFC refrigerants[PolyVinylEther  

SciTech Connect

Polyalkyleneglycol (PAG) and polyol ester (POE) have been developed as refrigeration lubricants, used with HFC134a. PAG is used for automotive air conditioning systems and POE is used for domestic reciprocating refrigerators and for A/C systems. Although PAG exhibits good lubricity performance, it is difficult to use for domestic reciprocating refrigerators due to its low dielectric property. POE is difficult to use for automotive A/C systems, due to hydrolysis and poor lubricity performance. Polyvinylether (PVE) can be used in place of PAG and POE with HFC refrigerants. PVE is used for A/C systems as well as refrigerator and freezer applications. PVE is an ideal lubricant for use with HFCs.

Kaneko, Masato; Sakanoue, Shuichi; Tazaki, Toshihiro; Tominaga, Shoichi; Takagi, Minoru; Goodin, M.

1999-07-01

14

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

NASA Astrophysics Data System (ADS)

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.

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

15

Study on the Interaction Coefficients in PR Equation with vdW Mixing Rules for HFC and HC Binary Mixtures  

NASA Astrophysics Data System (ADS)

The Peng-Robinson equation of state with the van der Waals mixing rules was used to correlate vapor-liquid equilibrium (VLE) data for HFC/HC, HFC/HFC, and HC/HC binary mixtures. The interaction parameter k ij was obtained for every binary mixture. It was assumed that k ij has contributions from the two components, and each component has its own constant contribution factor k i for the mixture, and the values of k ij indicate the degree in difference of properties between the two components. Therefore, the interaction parameters k ij is proposed as: k ij = k i - k j . The values of the mixing factor k i for Hydrofluorocarbons (HFCs) and Hydrocarbons (HCs), including propane, isobutane, n-butane, R23, R32, R125, R143a, R134a, R152a, R227ea R236fa, R236ea, and R245fa, were obtained by least-square fitting. In total, 39 refrigerant binary mixtures were analyzed on the basis of this method, and the results showed good agreement with experimental data. The overall average absolute deviations of pressure and vapor mole fraction are 1.3 % and 0.0089, respectively.

Chen, Jian-Xin; Hu, Peng; Chen, Ze-Shao

2008-12-01

16

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

...1Contaminated HFC-134a (R-134a) sample shall be standard contaminated HFC-134a (R-134a) refrigerant, 13.6 kg sample size, consisting of liquid HFC-134a (R-134a) with 1300 ppm (by weight) moisture at 21 °C (70 °F) and 45...

2014-07-01

17

Solubility, viscosity and density of refrigerant/lubricant mixtures  

SciTech Connect

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.

Henderson, D.R.

1993-01-01

18

Miscibility comparison for three refrigerant mixtures and four component refrigerants  

SciTech Connect

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

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

1999-07-01

19

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

SciTech Connect

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.

Gunsel, Selda; Pozebanchuk, Michael

1999-04-01

20

Measurements of the Saturated Liquid Density for HFC-134a+Oil Mixtures  

NASA Astrophysics Data System (ADS)

The present paper reports experimental results of the saturated liquid density for four combinations of HFC-134a and its compatible lubricants such as Polyalkyleneglycol (PAG) and Polyolester (POE) oils. The saturated liquid density is measured by the method using spherical buoys made of glass. The experiments have been conducted for temperatures from 256 to 313 K, densities from 933 to 1327 kg• m-3 and oil-concentrations from 0 to 1. The present results show that the saturated liquid density for HFC-134a+oil mixtures decreases with increasing oil-concentration at a constant-temperature while showing slightly positive or negative deviations from the mass fraction average for the experimental temperatures we have concerned.

Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

21

Condensation of Downward-Flowing Zeotropic Mixture HCFC-123/HFC-134a on a Staggered Bundle of Horizontal Low-Finned Tubes  

NASA Astrophysics Data System (ADS)

Expenmentswere conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134 a on a staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a m ass fraction at the tube bundle inlet were maintained at about 50°C and 14% respectively. The refrigerant mass velocity ranged from 9 to 33 kg/m2s, and the condensation temperature difference from 2 to 12K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for HCFC-123. However, the effect of fin geometry was much smaller for the mixture than for HCFC-123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. On the other hand, the mass transfer coefficient increased with condensation temperature difference. This was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube.

Honda, Hiroshi; Takamatsu, Hiroshi; Takata, Nobuo

22

Application of nanoparticles in domestic refrigerators  

Microsoft Academic Search

The reliability and performance of a domestic refrigerator with nanoparticles in the working fluid was investigated experimentally. Mineral oil with TiO2 nanoparticles mixtures were used as the lubricant instead of Polyol-ester (POE) oil in the 1,1,1,2-tetrafluoroethane (HFC134a) refrigerator. The compatibility of nonmetallic materials in the system with the HFC134a and mineral oil–nanoparticles mixtures was studied before the refrigerator performance tests.

Sheng-shan Bi; Lin Shi; Li-li Zhang

2008-01-01

23

From mine to refrigeration: a life cycle inventory analysis of the production of HFC134a  

Microsoft Academic Search

A life cycle inventory analysis has been conducted for the production of HFC-134a (1,1,1,2-tetrafluoroethane, CH2FCF3)11HFCs, or Hydrofluorocarbons, are compounds comprising hydrogen fluorine and carbon only. through from basic raw materials (crude oil, natural gas, sulphur and fluorspar) to the pure product delivered to industrial customers. The analysis was based on real industrial operations in Japan, USA and UK. It showed

A McCulloch; A. A Lindley

2003-01-01

24

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...

25

REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures  

National Institute of Standards and Technology Data Gateway

SRD 73 NIST REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures (PC database for purchase)   REFLEAK estimates composition changes of zeotropic mixtures in leak and recharge processes.

26

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

E-print Network

.S. and foreign literature on the use of a mixture of refrigerants rather than a single one in a refrigeration. A temperature-concentration diagram of an ideal binary solution at a given pressure has the characteristics and vapor, and subcooled liquid. The line separating the mixture region from the superheated vapor region

Oak Ridge National Laboratory

27

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

SciTech Connect

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.

Henderson, D.R.

1993-01-01

28

Thermodynamic properties of refrigerant mixtures. Final report, 21 Jun-21 Dec 89  

SciTech Connect

The objective of this project was to analyze the impact of refrigerant mixtures on refrigeration system capacity and components. A heat pump computer simulator was developed to predict the change in system capacity of two baseline air-conditioning systems as a function of refrigerant mixture concentration. Refrigerant mixtures made of refrigerants normally stocked on Air Force bases were considered.

Grzyll, L.R.; Silvestri, J.J.

1990-01-31

29

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

Microsoft Academic Search

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

M. A. Alsaad; M. A. Hammad

1998-01-01

30

Testing of propane\\/isobutane mixture in domestic refrigerators  

Microsoft Academic Search

The performance of a propane\\/isobutane (R290\\/R600a) mixture was examined for domestic refrigerators. A thermodynamic cycle analysis indicated that the propane\\/isobutane mixture in the composition range of 0.2 to 0.6 mass fraction of propane yields an increase in the coefficient of performance (COP) of up to 2.3% as compared to CFC12. For the actual tests, two commercial refrigerators of 299 and

Dongsoo Jung; Chong-Bo Kim; Kilhong Song

2000-01-01

31

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

NASA Technical Reports Server (NTRS)

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.

Westra, Douglas G.

1993-01-01

32

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

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

33

Frontiers in thermoacoustic refrigeration and mixture separation  

E-print Network

waves. Stirling's "hot-air engine" of the early 19th century was one of the first heat engines to use­ refrigerator systems for electric-power generation and air conditioning for military and civilian uses. Much thermally stratified, purely oscillating flow is desired. Gravity helps stabilize this thermal

34

Tubeside condensation of nonazeotropic refrigerant mixtures for two enhanced surfaces  

SciTech Connect

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.

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

1990-01-01

35

Prediciton of nucleate pool boiling heat transfer coefficients of refrigerant-oil mixtures  

Microsoft Academic Search

This paper describes an experimental investigation to determine the mechanism governing nucleate pool boiling heat transfer in refrigerant-oil mixtures, the role diffusion plays in this process, and the influence of the fluid mixture properties. Boiling heat transfer date were taken in mixtures of up to 10 per cent oil by weight in R-113. Thermophysical properties of the mixtures (density, viscosity,

M. K. Jensen; D. L. Jackson

1984-01-01

36

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

NASA Astrophysics Data System (ADS)

The Lorenz-Meutzner refrigerator freezer (RF) circuit has been proposed as a design which would operate with nonazeotropic 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 (approximately 3 percent) are seen for the NARM over R-12 in the same refrigerator freezer circuit. Modeling results and steady-state data suggest larger improvements (approximately 15 percent) 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.

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

37

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

EPA Science Inventory

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

38

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...

39

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...

40

Simulation of nonazeotropic refrigerant mixtures for use in a dual-circuit refrigerator/freezer with countercurrent heat exchangers  

SciTech Connect

The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. In a standard cabinet, this RF appears to provide energy savings of 24%, compared to current U.S. RF designs. The NARMs modeled with the best performance included R-32/-152a, R-22/-142b, and R-32/-142b. An 18% improvement can be expected from the dual-circuit system using R-12 alone, and an additional 6% improvement can be gained by replacing R-12 with the selected NARMs in countercurrent heat exchangers. The advantages of the system include greatly reduced energy consumption, easy temperature and humidity control for each compartment, no humidity or odors transferred between compartments, and increased time between defrost cycles.

Bare, J.C.; Gage, C.L.; Radermacher, R.; Jung, D.

1991-01-01

41

FLAME SUPPRESSION AND LUBRICANT INTERACTION OF HYDROCARBON MIXTURES FOR HOUSEHOLD REFRIGERATOR/FREEZERS  

EPA Science Inventory

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

42

Some observations of foaming characteristics in the nucleate boiling performance of refrigerant-oil mixtures  

SciTech Connect

This paper discusses the effect of lubricant oil on nucleate boiling performance for a smooth tube. The lubricant oil used in the investigation includes 3GS and 5GS, and the working refrigerant is R-22. Experiments were conducted at saturation temperatures of {minus}5 C, 4.4 C, and 20 C. For refrigerant-oil mixtures, the heat transfer coefficients, h, decrease with increase of oil concentrations at T{sub s} = 20 C. Conversely, for T{sub s} = {minus}5 C, the heat transfer coefficients for refrigerant-oil mixtures may be larger than those of pure refrigerants at low oil concentration. Possible explanations for this phenomenon include (1) the effect of physical properties, especially that of surface tension, and (2) foaming characteristics.

Wang, C.C.; Lin, Y.T.; Chung, H.D.; Hu, Y.Z.R.

1999-07-01

43

TESTING OF REFRIGERANT MIXTURES IN RESIDENTIAL HEAT PUMPS  

EPA Science Inventory

The report gives results of an investigation of four possibilities for replacing Hydrochlorofluorocarbon-22 (HCFC-22) with the non-ozone-depleting new refrigerants R-407D and R-407C in residential heat pumps. The first and simplest scenario was a retrofit with no hardware modific...

44

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

SciTech Connect

For the pure or azeotropic refrigerants typically used in present air conditioning and refrigeration applications, the refrigerant changes phase at a constant temperature. Thus, the refrigerant circuiting arrangement such as crossfiow, counterfiow, or cross-counterflow, has no effect on the thermal performance. For zeotropic refrigerant mixtures, however, the phase-change occurs over a temperature range, or "glide", and the refrigerant circuiting arrangement, or flow path through the heat exchanger, can affect the thermal performance of both the heat exchangers as well as the overall efficiency of the vapor compression cooling cycle. The effects of tsvo diflerent circuiting arrangements on the thermal performance of a zeotropic retligerant mixture and an almost azeotropic refrigerant mixture in a four-row cross-countertlow heat exchanger arrangement are reported here. The two condensers differ only in the manner of circuiting the refrigerant tubes, where one has refrigerant always flowing downward in the active heat transfer region ("identical order") and the other has refrigerant alternating flow direction in the active heat transfer region ("inverted order"). All other geometric parameters, such as bce are% fin louver geometry, refrigerant tube size and enhancement etc., are the same for both heat exchangers. One refrigerant mixture (R-41OA) un&rgoes a small temperature change ("low glide") during phase change, and the other retligerant mixture (a multi- component proprietary mixture) has a substantial temperature change ("high glide") of approximately 10"C during the phase change process. The overall thermal conductance, two-phase conductance, and pressure drop are presented. For the flow conditions of these tests, which are representative of resi&ntial cooling conditions, inverted order circuiting is more desirable than identical order. The potential thermal advantages of the i&ntical order arrangement for high-glide zeotropic refrigerant mixtures are negated by the increased parasitic refrigerant-side pressure drop utiortunately resulting from tkbrication requirements of the identical order circuiting.

Chen, D.T.; Conklin, J.C.

1999-03-15

45

Performance Analysis of heat pump cycle using CO2/DME refrigerant mixture  

NASA Astrophysics Data System (ADS)

Performance analyses have been carried out for a heat pump cycle using zeotropic refrigerant mixtures of carbon dioxide (CO2) and dimethyl ether (DME). In order to clarify the characteristics and coefficient of performance (COP) of CO2/DME heat pump cycle, the concentration of mixture was varied over a wide range. The calculation conditions were established as a hot-water supply system and the calculations were conducted by considering the heat transfer between the refrigerant and heat source/sink water. Because the heat transfer between refrigerant and heat source/sink water strongly affects on the cycle behavior, effects of the heat transfer capability parameter were investigated. The heat pump cycle is formed around the critical point for high CO2 concentration mixtures and it is formed under the critical point for low CO2 concentration mixtures. The COP has the maximum at a certain pressure for each mixture and the COPs of the mixture and pure DME are higher than that of pure CO2. Operating pressure decreases with increase of DME concentration. The effects of heat transfer between the refrigerant and heat source/sink water on characteristics of the cycle have also been clarified.

Onaka, Yoji; Miyara, Akio; Tsubaki, Koutaro; Koyama, Shigeru

46

Nucleate boiling heat transfer coefficients of pure halogenated refrigerants  

Microsoft Academic Search

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

Dongsoo Jung; Youngil Kim; Younghwan Ko; Kilhong Song

2003-01-01

47

The performance of propane\\/isobutane mixtures in a vapour-compression refrigeration system  

Microsoft Academic Search

Experiments have been conducted to investigate the performance of hydrocarbon refrigerants in a hermetic vapour-compression system. It is shown that propane and propane\\/isobutane mixtures may be used in an unmodified R12 system and give better COPs than R12 under the same operating conditions.

R. N. Richardson; J. S. Butterworth

1995-01-01

48

Simulation of nonazeotropic refrigerant mixtures for use in a dual-circuit refrigerator/freezer with countercurrent heat exchanges  

SciTech Connect

The paper discusses the simulation of Non-azeotropic Refrigerant Mixtures (NARMs) for use in a dual-circuit refrigerator/freezer (RF) with countercurrent heat exchangers. The simulated RF has two complete and independent refrigeration cycles for its two compartments. It uses a NARM in each cycle and countercurrent heat exchangers throughout. In a standard cabinet, the RF is simulated to provide energy savings of 24 percent compared to current U.S. RF designs. The NARMs modeled with the best performance are R-32/-152a, R-32/-142b, and R-22/-142b. An 18 percent improvement can be expected from the dual-circuit system using R-12 alone, and an additional 6 percent improvement can be gained by replacing R-12 with the selected NARMs in countercurrent heat exchangers. Advantages of the system include greatly reduced energy consumption, easy temperature and humidity control for each compartment, no humidity or odors transferred between compartments, and increased time between defrost cycles. Disadvantages include additional hardware requirements, compressor size, and the difficulties of using a NARM.

Bare, J.C.; Gage, C.L.; Radermacher, R.; Jung, D.S.

1992-01-01

49

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

Code of Federal Regulations, 2011 CFR

...polyalkylene glycol oil with 46-160 cst viscosity...fixture with electric motor) for up to 15 minutes...2000 rpm to circulate oil and refrigerant. The...minutes. 8.4Remove the oil reservoir, empty and...powered by an electric motor during recovery,...

2011-07-01

50

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

Code of Federal Regulations, 2010 CFR

...polyalkylene glycol oil with 46-160 cst viscosity...fixture with electric motor) for up to 15 minutes...2000 rpm to circulate oil and refrigerant. The...minutes. 8.4Remove the oil reservoir, empty and...powered by an electric motor during recovery,...

2010-07-01

51

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

Drop Correlations............. 21 2.2 The Overall Nucleate Boiling Contribution 25 3.1 Schematic Diagram ofExperimental Setup 36 3.2 Cut Away View of the Test Section 38 3.3 Oil SamplingDevice 42 3.4 Measurement ofBulk Temperautre 44 4.1 Comparison... Transfer Coefficient of HFC-32/HFC-125 at a Mass Flux of700 kg/m 2·s 117 6.1 The Effect ofNucleate Boiling and Convective Forces on Heat Transfer Coefficient........................................................... 126 6.2 The Effect ofMass Flux and Heat...

McJimsey, Bert Ashford

52

Lubricants for HFC-134a Compatible Rotary Compressors  

NASA Astrophysics Data System (ADS)

In replacing CFC-12 with HFC-134a for refrigerator compressors, the compatibility with lubricating oil, and lubrication in general, are of major concern. HFC-134a dose not have adequate solubility with current lubricating oils because of its molecular structure. Current oils also do not provide enough lubricating action when using HFC-134a. A new oil and new materials have to be utilized in order to use HFC-134a. Developing a new lubricating oil involved numerous tests of different combinations of many polyolester synthetic oils and additives. One of the pre-evaluated methods was pursued via sealed tube tests. Lubricated parts were selected by studies involving a plane-on-roller type of wear test machine and by analyzing the traces of acid material commonly created during the lubricating action. The matrices of new lubricating oils and new lubricated materials were estimated based on durability tests conducted on compressors and refrigerators. Results showed that polyolester synthetic oils having a low total acid value and including certain quantities of additives did not break down into a tar-like substance and they did not produce composite particles in the operating compressors and refrigerators. The study also found that ceramics and anti-corrosion alloy steel possessed good adrasion-reducing qualities. Based on our evaluation, we will implement compressor reliability tests and apply HFC-134a to rotary compressors for refrigerators.

Takaichi, Kenji; Sakai, Hisakazu

53

NEW CHEMICAL ALTERNATIVE FOR OZONE-DEPLETING SUBSTANCES: HFC-236FA  

EPA Science Inventory

The report gives results of a preliminary evaluation of a new hydrofluorocarbon (HFC)--HFC-236fa or 1,1,1,3,3,3-hexafluoropropane--as a possible alternative for chlorofluorocarbon (CFC)-114 (1,2-dichloro-1,1,2,2-tetrafluoroethane) refrigerant for chillers and as a possible fire s...

54

Chemical and thermal stability of refrigerant-lubricant mixtures with metals  

NASA Astrophysics Data System (ADS)

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 were selected from among two mineral oils and one alkylbenzene fluid. Each test mixture was aged at three temperature levels.

Huttenlocher, D. F.

1992-10-01

55

Flow boiling heat transfer coefficients at cryogenic temperatures for multi-component refrigerant mixtures of nitrogen-hydrocarbons  

NASA Astrophysics Data System (ADS)

The recuperative heat exchanger governs the overall performance of the mixed refrigerant Joule-Thomson cryocooler. In these heat exchangers, the non-azeotropic refrigerant mixture of nitrogen-hydrocarbons undergoes boiling and condensation simultaneously at cryogenic temperature. Hence, the design of such heat exchanger is crucial. However, due to lack of empirical correlations to predict two-phase heat transfer coefficients of multi-component mixtures at low temperature, the design of such heat exchanger is difficult.

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

2014-01-01

56

An experimental evaluation of two nonazeotropic refrigerant mixtures in a water-to-water breadboard heat pump  

NASA Astrophysics Data System (ADS)

As part of the Department of Energy/Oak Ridge National Laboratory Building Equipment Research program, the National Institute of Standards and Technology constructed an experimental, easily reconfigurable, water-to-water, breadboard heat pump apparatus in order to compare pure R22 to nonazeotropic refrigerant mixtures. Performance of the heat pump charged with a range of compositions of the binary mixtures R22/RI14 and R13/R12 were compared to R22. The advantage claimed for mixtures in this application is improved thermodynamic efficiency as a result of gliding refrigerant temperatures in the evaporator and condenser in low lift, high glide applications typical of air conditioning.

Kauffeld, Michael; Mulroy, William; McLinden, Mark; Didion, David

1990-02-01

57

Pool boiling heat transfer of refrigerant mixtures R32/R125  

SciTech Connect

Nucleate pool boiling heat transfer of new, environmentally harmless refrigerant mixtures R32/R125 has been systematically investigated in a wide range of pressure and heat flux under saturation conditions using a horizontal platinum wire (d = 0.1 mm). The platinum wire served as both heating element and resistance thermometer. The experimental results are compared with calculated values using a modified Jungnickel correlation. The comparison between all calculated data and experimental data shows good agreement. Most of the data fall within {+-}20% of the correlation. The mean average deviation is {+-}8.25%.

Shen, J.; Spindler, K.; Hahne, E.

1999-11-01

58

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

Microsoft Academic Search

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

D. L. Hinton; J. C. Conklin; E. A. Vineyard

1992-01-01

59

Refrigeration Circuit Employed New Refrigerant  

NASA Astrophysics Data System (ADS)

There is urgent need to develop alternative refrigerants following the amendments to the Fourth Montreal Protocol regarding the regulation for HCFC's that is effective from January 1, 1996, and eventual the phase out of HCFC's production, currently scheduled for the year 2030. These alternative refrigerant shave less affect to ward the global environment, but are required to meet many conditions such as safety, thermal characteristics, stability, price, energy efficiency, behavior with lubricants and materials and so on. This report explains the current status of evaluation of candidates, and suggest about what is the best way to choice the best alternative refrigerant for the Air-conditioners, including the environmentally acceptability and safety. And explain the development for technologies to make good use of new HFC refrigerants and issues for them.

Ohnishi, Haruo

60

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...

61

Vapor-Liquid Equilibrium Measurements of the Binary R32+R125 Refrigerant Mixture  

NASA Astrophysics Data System (ADS)

Vapor-liquid equilibrium (VLE) data of the binary R32+R125 refrigerant mixture including R410A (50mass% R32 + 50mass% R125) were obtained by the circulation-type experimental apparatus with a liquid-bath thermostat. VLE measurements were carried out in the temperatures between 263.15 K and 318.15 K and in the pressures between 505 kPa and 2724 kPa. The experimental uncertainties of temperature, pressure, and composition measurements were estimated to be within 3 mK, 0.1 %, and 0.4 %, respectively. The present data were compared with reported experimental data against the REFPROP 6.01 as well as REFPROP 7.0 calculation results.

Higashi, Yukihiro; Miyake, Takeshi; Fujii, Ken-Ichi

62

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

National Technical Information Service (NTIS)

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 o...

D. R. Henderson

1993-01-01

63

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

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

64

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...

65

NEW CHEMICAL ALTERNATIVE FOR OZONE-DEPLETING SUBSTANCES: HFC-236EA  

EPA Science Inventory

The report gives results of a preliminary evaluation of a new hydrofluorocarbon (HFC-236ea or 1, 1, 1, 2, 3, 3-hexafluoropropane) as a possible alternative for chlorofluorocarbon (CFC)-114 (1, 2-dichloro-1, 1, 2, 2-tetrafluoroethane) refrigerant in chillers and high-temperature i...

66

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...

67

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

68

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

69

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

70

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

71

Polybasic esters: Novel synthetic lubricants designed for use in HFC compressors  

SciTech Connect

The replacement of ozone-depleting refrigerants with ozone-friendly hydrofluorocarbons (HFCs) requires the use of lubricants that have not historically been used in refrigeration compressors and systems. Polyalkylene glycol (PAG) and polyol ester (POE) lubricants have been extensively evaluated in various refrigeration applications and are being used commercially. Novel synthetic lubricants have been developed based on polybasic esters (PBEs) resulting from malonate-acrylate Michael adducts. These lubricants were designed to address problems encountered in current HFC systems. PBE-based fluids show desired miscibility with R-134a and other HFC blends, excellent hydrolytic stability, no copper plating (even in wet systems), and excellent lubricity. All of these properties are obtained without the use of performance-enhancing additives. Key physical property data, bench and compressor test results, and compatibility study results will be presented.

Lilje, K.C.; Sabahi, M. [Albemarle Corp., Baton Rouge, LA (United States); Hamid, S. [Huels America, Inc., Piscataway, NJ (United States)

1995-12-31

72

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

SciTech Connect

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.

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

2002-08-30

73

Design of oil-free simple turbo type 65 K/6 KW helium and neon mixture gas refrigerator for high temperature superconducting power cable cooling  

NASA Astrophysics Data System (ADS)

For the requirement of HTS facility cooling, we propose oil-free simple turbo-type refrigerator. The working gas is a helium and neon mixture. Two single-stage turbo compressors and two expansion turbines are applied to the cycle. The rotor consists of the compressor impeller, turbine impeller and driving motor, and is supported by foil type gas bearing. The refrigerator requires two rotating machines with excellent reliability and compactness, and the motor power required is 72.5 kW for a refrigeration load of 6 kW. For the cooling of power cable, sub-cooled pressurized liquid nitrogen and a circulation pump must be provided. If the estimated distance between inter-cooling stations is quite long, for example 5 km, plural refrigerators may be set up on one cooling station.

Saji, N.; Asakura, H.; Yoshinaga, S.; Ishizawa, T.; Miyake, A.; Obata, M.; Nagaya, S.

2002-05-01

74

Refrigeration and thermometry of liquid3He-4He mixtures in the ballistic regime  

NASA Astrophysics Data System (ADS)

The ballistic regime of liquid3He-4He mixtures is characterized by a large mean free path ? of the thermal excitations compared to the characteristic dimension of the experiment. We report on investigations of the transport properties of mixtures as well as superfluid3He in the ballistic regime by means of the vibrating wire technique. In order to avoid possible sources of heat leaks into the liquid, the experimental setup was built as far as possible of pure materials only. The contribution of a Ag sinter to the heat leak as well as its influence on the attainable minimum temperature of the mixtures were investigated by performing measurements in two similar setups which differed in the size of the heat exchanger by about one order of magnitude. Moreover, we have used the vibrating wire partly immersed in the superfluid3He-B phase of a phase-separated mixture as a very sensitive, continuously monitoring thermometer for liquid mixtures in their ballistic regime. The achieved minimum temperature of a 6.8%-mixture at p = 0.35 bar and of a 9.5%-mixture at p = 9.8 bar was 130 ?K. This value can be considered as an upper limit for the temperature of the mixtures as the damping of the vibrating wire thermometer saturates at this temperature due to its intrinsic properties.

König, R.; Betat, A.; Pobell, F.

1994-11-01

75

Energy Efficient, Environmentally Friendly Refrigerants  

E-print Network

refrigerants have become expensive or unavailable. A safe, environmentally friendly, high performance refrigerant mixture for replacement of R-12 and R-134a has been developed. The mixture, designated Ikon B, is nonflammable, has zero ozone depletion potential...

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

76

The large contribution of projected HFC emissions to future climate forcing  

PubMed Central

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

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

2009-01-01

77

Performance of an auto refrigerant cascade refrigerator operating in gas refrigerant supply (GRS) mode with nitrogen-hydrocarbon and argon-hydrocarbon refrigerants  

NASA Astrophysics Data System (ADS)

There is a worldwide interest in the development of auto refrigerant cascade (ARC) refrigerators operating with refrigerant mixtures. Both flammable and non-flammable refrigerant mixtures can be used in these systems. The performance of an ARC system with optimum nitrogen-hydrocarbon and argon-hydrocarbon mixtures between 90 and 160 K is presented in this paper.

Gurudath Nayak, H.; Venkatarathnam, G.

2009-07-01

78

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)

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.

Akasaka, Ryo

79

Tribological Studies on Scuffing Due to the Influence of Carbon Dioxide Used as a Refrigerant in Compressors  

Microsoft Academic Search

Because hydrofluorocarbon (HFC) refrigerants in air-conditioning systems are known to have a negative effect on the environment, carbon dioxide (CO2) is a candidate as a replacement refrigerant. Research work related to CO2 as a refrigerant has been focused primarily on its thermodynamic performance, whereas work in the area of tribology related to carbon dioxide is absent. In this study, the

NICHOLAOS G. DEMAS; ANDREAS A. POLYCARPOU; THOMAS F. CONRY

2005-01-01

80

ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment  

NASA Astrophysics Data System (ADS)

In this paper the reliability and performance of a vapour compression refrigeration system with ZnO nanoparticles in the working fluid was investigated experimentally. Nanorefrigerant was synthesized on the basis of the concept of the nanofluids, which was prepared by mixing ZnO nanoparticles with R152a refrigerant. The conventional refrigerant R134a has a global warming potential (GWP) of 1300 whereas R152a has a significant reduced value of GWP of 140 only. An experimental test rig is designed and fabricated indigenously in the laboratory to carry out the investigations. ZnO nanoparticles with refrigerant mixture were used in HFC R152a refrigeration system. The system performance with nanoparticles was then investigated. The concentration of nano ZnO ranges in the order of 0.1% v, 0.3% v and 0.5%v with particle size of 50 nm and 150 g of R152a was charged and tests were conducted. The compressor suction pressure, discharge pressure and evaporator temperature were measured. The results indicated that ZnO nanorefrigerant works normally and safely in the system. The ZnO nanoparticle concentration is an important factor considered for heat transfer enhancement in the refrigeration system. The performance of the system was significantly improved with 21% less energy consumption when 0.5%v ZnO-R152a refrigerant. Both the suction pressure and discharge pressure were lowered by 10.5% when nanorefrigerant was used. The evaporator temperature was reduced by 6% with the use of nanorefrigerant. Hence ZnO nanoparticles could be used in refrigeration system to considerably reduce energy consumption. The usage of R152a with zero ozone depleting potential (ODP) and very less GWP and thus provides a green and clean environment. The complete experimental results and their analysis are reported in the main paper.

Sendil Kumar, D.; Elansezhian, R.

2014-03-01

81

A new type mixture refrigeration auto-cascade cycle with partial condensation and separation reflux exchanger and its preliminary experimental test  

NASA Astrophysics Data System (ADS)

A new type of mixture refrigeration cycle with reflux exchanger is presented in this paper. In this cycle, a new type of L-V separator with inner heat and mass transfer is employed to replace the combination of conventional L-V separator or complicated rectifier and succeeding heat exchanger used in traditional auto-cascade cycle or Kleemenko cycle. A prototype is developed based on this refrigeration cycle. The thermodynamic performance is discussed as well as some other specifications such as cost, reliability, etc. The experimental results show that this prototype can reach 74 W at 135 K and 265 W at 171 K with a nominal input power of 1.5 HP.

Wu, J. F.; Gong, M. Q.; Liu, J. L.; Luo, E. C.; Qi, Y. F.; Hu, Q. G.

2002-05-01

82

Reliability of Heat Pumps Containing R410-A Refrigerant  

E-print Network

years. High volume production through these years has helped manufacturers to produce reliable products. R- 4104 a hydrofluorocarbon (HFC) mixture, is a leading candidate to replace R-22 in residential and light commercial air conditioners and heat pumps...

McJimsey, B. A.; Cawley, D.

1998-01-01

83

Investigation into the fractionation of refrigerant blends. Final technical report, March 1994--December 1995  

SciTech Connect

As a means of complying with current and impending national and international environmental regulations restricting the use and disposal of conventional CFC and HCFC refrigerants which contribute to the global ozone depletion effects, the HVAC industry is vigorously evaluating and testing BFC refrigerant blends. While analyses and system performance tools have shown that BFC refrigerant blends offer certain performance, capacity and operational advantages, there are significant possible service and operational issues that are raised by the use of blends. Many of these issues occur due to the fractionation of the blends. Therefore, the objective of this program is to conduct analyses and experimental tests aimed at understanding these issues, develop approaches or techniques to predict these effects and convey to the industry safe and reliable approaches. As a result, analytical models, verified by laboratory data, have been developed that predict the fractionation effects of HFC refrigerant blends when (1) exposed to selected POE lubricants, (2) during the system charging process from large liquid containers, and (3) during system startup, operation and shutdown within various system components (where two-phase refrigerant exists), and during selected system and component leakage scenarios. Model predictions and experimental results are presented for HFC refrigerant blends containing HFC-32, HFC-134a, and HFC-125 and the data are generalized for various operating conditions and scenarios.

Biancardi, F.R.; Michels, H.; Sienel, T.; Pandy, D.

1996-01-01

84

Study on the compatibility of insulation materials for hermetic motor under alternative refrigerants and new lubricants atmosphere  

NASA Astrophysics Data System (ADS)

HFC407C and HFC410A were introduced as the alternative refrigerants for HCFC22 in air conditioner to follow the Motreal protocol. But HFCs were also regulated by the Kyoto protocol and natural refrigerants like hydrocarbon (HC) and CO2 are researched and introduced in the market. Under these circumstances the compatibility of motor insulation materials for hermetic motor under alternative refrigerants and lubricants become important. In this paper we discuss the compatibility of magnet wires and films of hermetic motor for air conditioner under atmosphere of HFC407C and HFC410A with POE and PVE lubricants and also discuss it under atmosphere of R600a with mineral oil and CO2 with PAG lubricant in comparison of conventional atmosphere.

Komatsubara, Takeo; Sunaga, Takeshi; Takahashi, Yasuki

85

Atmospheric histories and global emissions of the anthropogenic hydrofluorocarbons HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa  

E-print Network

We report on ground-based atmospheric measurements and emission estimates of the four anthropogenic hydrofluorocarbons (HFCs) HFC-365mfc (CH[subscript 3]CF[subscript 2]CH[subscript 2]CF[subscript 3], 1,1,1,3,3-pentafluorobutane), ...

Rigby, Matthew

86

New immiscible refrigeration lubricant for HFCs  

SciTech Connect

This study examines the capability of a family of very low-viscosity alkylbenzenes (AB) used in high-side rotary compressors for HFCs. In the development of refrigeration lubricants for HFCs, miscibility is one of the most important problems to be solved. Therefore, PAG (polyalkylene glycols) and POE (polyol esters), which have good miscibility, have been applied in new HFC applications. However, it is difficult for these lubricants to maintain long-term durability in high-side rotary compressors. In friction tests under high HFC pressure, ABs with much lower viscosities than mineral oil maintained a much stronger oil film than the combination of mineral oil/R-12 or POE/HFCs. These results were also proven by compressor durability tests. From the study of the solubility of ABs and HFCs, it is suggested that the total amount of refrigerant can be reduced because HFCs are barely soluble with ABs inside the high-side shell.

Sunami, Motoshi [Nippon Oil Co. Ltd., Tokyo (Japan). Lubricant Marketing and Product Engineering Dept.; Takigawa, Katsuya; Suda, Satoshi; Sasaki, Umekichi [Nippon Oil Co. Ltd., Yokohama (Japan). Central Technical Research Lab.

1995-12-31

87

Thermodynamic Properties for A Drop-in Refrigerant R-SP34E  

NASA Astrophysics Data System (ADS)

Although a transition into several promising HFC alternative refrigerants and their mixtures from conventional CFC and/or HCFC refrigerants is steadily in progress, there still remains a niche to pursue a drop-in refrigerant in some limited engineering applications where the advantage of retrofitting can be emphasized.R-SP34E is one of such drop-in refrigerants to complement R-12 which is a ternary mixture refrigerant consisted of R-134a with minor fractions of propane and ethanol. In this paper, the fundamental thermodynamic properties such as VLE properties and gas-phase PVT properties of R-SP34E are presented. This paper reports the first sets of measured data including 7 dew-and bubble-point pressures and 73 gas-phase PVT properties in the extensive range of temperatures 300-380 K, pressures 0.1-5.2 MPa, and densities up to around the critical density, obtained by employing the Burnett apparatus. In order to complement and confirm the reliability of the measurements, thermodynamic models including a dew-point pressure correlation and a truncated virial equation of state were originally developed in this study. The models were confirmed to exhibit not only excellent reproducibility of the measurements but also the thermodynamic consistency regarding the temperature dependence of the second and third virial coefficients and derived properties such as specific heats or speed of sound. By presenting the reliable thermodynamic model, a systematic information about the thermodynamic properties of R-SP34E is provided in this paper.

Kayukawa, Yohei; Hondo, Takashi; Watanabe, Koichi

88

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

NASA Astrophysics Data System (ADS)

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.

Sukornick, B.

1989-05-01

89

Modeling and testing of fractionation effects with refrigerant blends in an actual residential heat pump system  

SciTech Connect

The heating, ventilating, and air-conditioning (HVAC) industry is actively evaluating and testing hydrofluorocarbon (HFC) refrigerant blends as a means of complying with current and impending national and international environmental regulations restricting the use and disposal of conventional chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants that contribute to the global ozone-depletion effects. While analyses and system performance tools have shown that HFC refrigerant blends offer certain performance, capacity, and operational advantages, there are significant possible service and operational issues that are raised by the use of blends. Many of these issues occur due to the fractionation of the blends. Therefore, the objective of this program was to conduct analyses and experimental tests aimed at understanding these issues, develop approaches or techniques to predict these effects, and convey to the industry safe and reliable approaches. As a result, analytical models verified by laboratory data have been developed that predict the fractionation effects of HFC refrigerant blends (1) when exposed to selected POE lubricants, (2) during the system charging process from large liquid containers, and (3) during system start-up, operation, and shutdown within various system components (where two-phase refrigerant exists) and during selected system and component leakage scenarios. Model predictions and experimental results are presented for HFC refrigerant blends containing R-32, R-134a, and R-125 and the data are generalized for various operating conditions and scenarios.

Biancardi, F.R.; Pandy, D.R.; Sienel, T.H.; Michels, H.H. [United Technologies Research Center, East Hartford, CT (United States)

1997-12-31

90

Performance of an auto refrigerant cascade refrigerator operating in liquid refrigerant supply (LRS) mode with different cascade heat exchangers  

NASA Astrophysics Data System (ADS)

Auto refrigerant cascade (ARC) refrigerators operating with zeotropic mixtures provide refrigeration at temperatures less than 173 K (-100 °C) using a single compressor. Different authors have suggested different cascade heat exchangers for ARC refrigerators. There is no study in literature that suggests at what temperature ranges one, two or three cascade heat exchangers are necessary. In this paper the performance of an ARC refrigerator operating in the liquid refrigerant supply mode and operating with optimized hydrocarbon mixtures and different cascade heat exchangers is studied. The optimum number of cascade heat exchangers (stages) to be used for different operating temperatures is suggested.

Gurudath Nayak, H.; Venkatarathnam, G.

2010-11-01

91

Mixtures  

NSDL National Science Digital Library

Mixtures allows exploration of percents through two piles of colored and uncolored chips. The user must decide how many chips to color to create the desired percentage of colored chips compared to the total pile. Mixtures is one of the Interactivate assessment explorers.

92

Ultra High Pressure Tribometer for Testing CO2 Refrigerant at Chamber Pressures up to 2000 psi to Simulate Compressor Conditions  

Microsoft Academic Search

The growing interest for using the natural refrigerant carbon dioxide (CO2) in refrigeration and air-conditioning applications instead of HFC refrigerants, due to environmental concerns, has led to the development of an ultra high pressure tribometer (UHPT) specifically tailored for testing in CO2 environment. The existing research on tribology related to CO2 environment has focused on investigations at relatively low chamber

NICHOLAOS G. DEMAS; ANDREAS A. POLYCARPOU

2006-01-01

93

Control software for data/HFC systems  

NASA Astrophysics Data System (ADS)

TCP/UDP/IP data transport over hybrid fiber coaxial cable (HFC) networks for Internet or enterprise service requires new approaches for scaling, provisioning, authentication, service differentiation and quality of service. MAC layer bridging alone at the head end will fail to provide scaling, conditional access, and quality of service. Additionally, the half duplex, shared nature of the HFC network and the need for multiple return paths per forward path, will encourage the use of packet layer routing in the head end. Data/cable industry suppliers have been concentrating on physical and link layer issues such as modulation, forward error correction and media access control (MAC) protocols. Less thought has been given to system software issues which are crucial to scaling residential broadband networks. By scaling, we mean the capability to provision, diagnose, manage and ensure expected performance when thousands or millions of subscribers are attached. This paper describes some software scaling issues and discusses cable DHCP and virtual dialup as examples of software scaling solutions.

Abe, George

1996-11-01

94

Alternative refrigerants and refrigeration cycles for domestic refrigerators  

SciTech Connect

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.

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

1992-12-01

95

Experimental evaluation of automotive air-conditioning using HFC-134a and HC-134a  

NASA Astrophysics Data System (ADS)

An experimental study to evaluate the energy consumption of an automotive air conditioning is presented. In this study, these refrigerants will be tested using the experimental rig which simulated the actual cars as a cabin complete with a cooling system component of the actual car that is as the blower, evaporator, condenser, radiators, electric motor, which acts as a vehicle engine, and then the electric motor will operate the compressor using a belt and pulley system, as well as to the alternator will recharge the battery. The compressor working with the fluids HFC-134a and HC-134a and has been tested varying the speed in the range 1000, 1500, 2000 and 2500 rpm. The measurements taken during the one hour experimental periods at 2-minutes interval times for temperature setpoint of 20°C with internal heat loads 0, 500, 700 and 1000 W. The final results of this study show an overall better energy consumption of the HFC-134a compared with the HC-134a.

Nasution, Henry; Zainudin, Muhammad Amir; Aziz, Azhar Abdul; Latiff, Zulkarnain Abdul; Perang, Mohd Rozi Mohd; Rahman, Abd Halim Abdul

2012-06-01

96

Malone refrigeration  

SciTech Connect

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

Swift, G.W.

1993-01-01

97

Thermoacoustic refrigeration  

NASA Technical Reports Server (NTRS)

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.

Garrett, Steven L.; Hofler, Thomas J.

1991-01-01

98

Thermotile Refrigerators  

NASA Technical Reports Server (NTRS)

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.

Park, Brian V.

1994-01-01

99

Malone refrigeration  

SciTech Connect

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

Swift, G.W.

1993-06-01

100

Oil-return characteristics of refrigerant oils in split heat pump system  

SciTech Connect

Currently, HFC substitute refrigerants for R-22 are being evaluated in air-conditioning and heat pump applications. The oil return characteristics and heat transfer effects of the lubricants are being studied again. Based on commercial refrigeration experience POEs are the lubricants of choice for HFC refrigerants. POEs have two major drawbacks: hygroscopicity and high cost. Thus the question is raised to what extent is it possible to replace POEs with a lower cost, but immiscible, oil such as mineral oil. It is the purpose of this study to experimentally investigate the oil return behavior of R-407C with mineral oil in a split three-ton heat pump in comparison to R407C/POE and R-22/Mineral Oil.

Sundaresan, S.G. [Copeland Corp., Sidney, OH (United States). Materials Engineering and Systems Chemistry; Radermacher, R.

1996-08-01

101

Surface Tension of Alternative Refrigerants  

NASA Astrophysics Data System (ADS)

In this paper, current researches for surface tension of alternative refrigerants are reviewed. The refrigerants of interests are seven HCFCs: namely R-123, R-123a, R-124, R -141b, R-142b, R-225ca and R-225cb, and six HFCs; namely R-23, R-32, R-125, R-134, R- 134a and R-152a. The available data and correlations of experimental surface tension for HCFCs and HFCs are summarized. Most of experimental data were obtained by using capillary rise method. With regard to R-123 and R-134a, new surface tension correlations have been developed and are accepted as the international standard. For other refrigerants, the author selected one correlation for each refrigerant as a recommended correlation. In addition, graphical estimation method of surface tension for binary mixture is introduced. In particular, more research is expected on the surface tension of mixture in the future.

Okada, Masaaki

102

46 CFR 154.1735 - Methyl acetylene-propadiene mixture.  

Code of Federal Regulations, 2010 CFR

...acetylene-propadiene mixture must have a refrigeration system without vapor compression or have a refrigeration system with the following features...separate cargo piping, vent piping, and refrigeration equipment for methyl...

2010-10-01

103

Atmospheric trend and emission estimates for HFC-43-10mee (1999 to 2010)  

NASA Astrophysics Data System (ADS)

We present the first atmospheric measurements of HFC-43-10mee (1,1,1,2,2,3,4,5,5,5-decafluoropentane), an anthropogenic gas introduced in the mid-1990s as a substitute for CFC-113 (1,1,2-trichlorotrifluoroethane). The global warming potential of this HFC (hydrofluorocarbon) has been reported as 1640 (100-year time horizon), hence, its inclusion within a class of chemicals in the Kyoto Protocol and now its consideration for addition in the Montreal Protocol. Commercial HFC-43-10mee is a mixture of two diastereomers; both detectable using the Medusa GC-MS cryogenic trapping system (Miller et al., 2008), and included in our calculations for total HFC-43-10mee concentration. Chen et al. [2010] recently reported that the diastereomers have identical lifetimes in the troposphere of ?18 years. Our northern hemisphere (NH) tropospheric record spans from 1999 to present day, utilizing 12 archive samples together with recent in situ measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) program at Trinidad Head and La Jolla, California. Precisions of < 0.01 ppt (parts-per-trillion, dry air mole fraction) allow for observation of an accelerated rise from 0.04 ppt in 2000 (growth rate of 0.01 ppt/yr) to 0.10 ppt in 2005 (0.02 ppt/yr) and 0.21 ppt in 2010 (0.03 ppt/yr). From the experimentally defined mole fractions in the background NH, we estimate the growth trend in the southern hemisphere using a simple box model which includes the stratosphere. Further, we estimate ‘top-down’ emissions to the global atmosphere for 2009 at ? 1200 tonnes. ‘Bottom-up’ estimates from the Emission Database for Global Atmospheric Research (EDGAR) v.4.0 only include emissions from Austria and France in 2005, which total 206 tonnes. For comparison, the global emissions in 2005 from our model equate to ? 800 tonnes. Further measurement and modeling efforts are warranted together with projections of future consumption. References: Miller, B. R., R. F. Weiss, P. K. Salameh, T. Tanhua, B. R. Greally, J. Mühle, and P. G. Simmonds (2008), Medusa: A sample preconcentration and GC/MS detector system for in situ measurements of atmospheric trace halocarbons, hydrocarbons and sulfur compounds, Anal. Chem., 80, 1536- 1545. Chen, L., S. Uchimaru, K. Kutsuna, K.Tokuhashi and A. Sekiya (2010), Kinetics study of gas-phase reactions of erythro/threo-CF3CHFCHFC2F5 with OH radicals at 253-328 K, Chem. Phys. Lett., 488, 22-26

Arnold, T.; Ivy, D. J.; Muhle, J.; Harth, C. M.; Salameh, P.; Weiss, R. F.

2010-12-01

104

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

105

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

E-print Network

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 ...

Miller, Franklin K., 1970-

2005-01-01

106

HFC-6000 for Nuclear I and C Upgrade  

SciTech Connect

The scalability of the HFC-6000 product line makes it an effective solution for nuclear power plant I and C upgrade applications. Its 19-in. rack-mounted platform provides a modular structure whose components can be used for many different nuclear power plant safety applications. This single-platform solution reduces the overall complexity of I and C implementation by minimizing operational and maintenance requirements. The HFC-6000 product line is designed to operate with either single or multiple control remote units in each channel. The main controller module in a remote unit is the system controller (HFCSBC06), which executes control logic programs, I/O scan, and C-Link communication. All three functions are handled by dedicated 64/32-bit microprocessors. A redundant configuration of system controllers consists of two HFC-SBC06 modules and one HFC-DPM06 dual-ported memory module. The hardware interface with external peripheral equipment is provided by an HFC-PCC06 peripheral interface module in the same rack. This module communicates with dedicated Control Switch Modules (the operator interface for digital control) and M/A stations (the operator interface for analog control), which are mounted on the plant main control board. Individual input/output modules serve as the hardware interface with the field devices under control and are implemented by different types of I/O modules. Each I/O module has a redundant serial communication interface. This serial interface employs a proprietary poll-response intercommunication link (ICL) protocol for communication with the system controllers. When a remote is configured with redundant controllers, the two ICL interfaces on each I/O module are connected to separate system controllers to create a redundant link. The I/O modules can be installed locally or remotely. If the I/O modules are physically remote from the controller, the ICL can be implemented with fiber optics to provide physical and electrical isolation from non-safety components. An HFC-FPD06 Flat Panel Display Module can be used as a human-machine interface (HMI). This HMI is composed of a qualified flat panel display and an HFC-FPC06 FPD controller. The FPC06 module has hardware interfaces for both the ICL and the fast Ethernet C-Link. It is configured as a subordinate to the HFC-SBC06 system controller and controls graphic displays on the HMI; it can also perform data voting and validation functions for redundant or triple redundant safety channels. The HFC-FPC06 can be used in either single or redundant configurations. The Power Supply Module consists of a redundant, rack-mounted power supply set. The typical configuration provides 24-vdc for all logic functions and 48-vdc for excitation power. Individual power supplies are redundant and hot swappable. Currently, HFC-6000 system is being installed in Kori Units no.1 to no.4 for its AAC D/G control and monitoring system and several other NPP I and C upgrade projects. (authors)

Taylor, Jonathan; Hsu, Allen; Gerardis, Terry; Stevens, John; McCreary, Tim; Yang, Steve [HF Controls Corporation, 16650 Westgrove Dr., Suite 500s (United States)

2006-07-01

107

SAFETY FEATURES OF HC REFRIGERANTS IN CAR AIR CONDITIONING  

Microsoft Academic Search

Hydrocarbon (HC) refrigerants are environmentaly safe, readily available, non toxic, and have good thermodynamic and transfer properties. However, they are also flammable. The subject of this paper is the effect of leakage of refrigerant into the passenger compartment of a vehicle from an assumed fracture in the refrigerant circuit. If the resultant mixture in the passenger compartment is close to

DUSAN R. TOSOVIC; IAN L. MACLAINE-CROSS

108

Properties and Cycle Performance of Refrigerant Blends Operating Near and Above the Refrigerant Critical Point, Task 2: Air Conditioner System Study  

SciTech Connect

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 conducting comprehensive measurements of thermophysical for refrigerant R125 and refrigerant blends R410A and R507A and developing new equation of state formulations and mixture models for predicting thermophysical properties of HFC refrigerant blends. Part 2 of this project conducted performance measurements of split-system, 3-ton R22 and R410A residential air conditioners in the 80 to 135 F (27.8 to 57.2 C) outdoor temperature range and development of a system performance model. The performance data was used in preparing a beta version of EVAP-COND, a windows-based simulation package for predicting performance of finned-tube evaporators and condensers. The modeling portion of this project also included the formulation of a model for an air-conditioner equipped with a thermal expansion valve (TXV). Capacity and energy efficiency ratio (EER) were measured and compared. The R22 system's performance was measured over the outdoor ambient temperature range of 80 to 135 F (27.8 to 57.2 C). The same test range was planned for the R410A system. However, the compressor's safety system cut off the compressor at the 135.0 F (57.2 C) test temperature. The highest measurement on this system was at 130.0 F (54.4 C). Subsequently, a custom-manufactured R410A compressor with a disabled safety system and a more powerful motor was installed and performance was measured at outdoor temperatures up to 155.0 F (68.3 C). Both systems had similar capacity and EER performance at 82.0 F (27.8 C). The capacity and EER degradation of both systems were nearly linearly dependent with rising ambient outdoor ambient test temperatures. The performance degradation of R410A at higher temperatures was greater than R22. However, the R22 and R410A systems both operated normally during all tests. Visual observations of the R410A system provided no indication of vibrations or TXV hunting at high ambient outdoor test conditions with the compressor operating in the transcritical regime.

Piotr A. Domanski; W. Vance Payne

2002-10-31

109

Refrigeration Showcases  

NASA Technical Reports Server (NTRS)

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.

1997-01-01

110

Global emissions of HFC-143a (CH3CF3) and HFC-32 (CH2F2) from in situ and air archive atmospheric observations  

NASA Astrophysics Data System (ADS)

High-frequency, in situ observations from the Advanced Global Atmospheric Gases Experiment (AGAGE), for the period 2003 to 2012, combined with archive flask measurements dating back to 1977, have been used to capture the rapid growth of HFC-143a (CH3CF3) and HFC-32 (CH2F2) mole fractions and emissions into the atmosphere. Here we report the first in situ global measurements of these two gases. HFC-143a and HFC-32 are the third and sixth most abundant hydrofluorocarbons (HFCs) respectively and they currently make an appreciable contribution to the HFCs in terms of atmospheric radiative forcing (1.7 ± 0.04 and 0.7 ± 0.02 mW m-2 in 2012 respectively). In 2012 the global average mole fraction of HFC-143a was 13.4 ± 0.3 ppt (1?) in the lower troposphere and its growth rate was 1.4 ± 0.04 ppt yr-1; HFC-32 had a global mean mole fraction of 6.2 ± 0.2 ppt and a growth rate of 1.1 ± 0.04 ppt yr-1 in 2012. The extensive observations presented in this work have been combined with an atmospheric transport model to simulate global atmospheric abundances and derive global emission estimates. It is estimated that 23 ± 3 Gg yr-1 of HFC-143a and 21 ± 11 Gg yr-1 of HFC-32 were emitted globally in 2012, and the emission rates are estimated to be increasing by 7 ± 5% yr-1 for HFC-143a and 14 ± 11% yr-1 for HFC-32.

O'Doherty, S.; Rigby, M.; Mühle, J.; Ivy, D. J.; Miller, B. R.; Young, D.; Simmonds, P. G.; Reimann, S.; Vollmer, M. K.; Krummel, P. B.; Fraser, P. J.; Steele, L. P.; Dunse, B.; Salameh, P. K.; Harth, C. M.; Arnold, T.; Weiss, R. F.; Kim, J.; Park, S.; Li, S.; Lunder, C.; Hermansen, O.; Schmidbauer, N.; Zhou, L. X.; Yao, B.; Wang, R. H. J.; Manning, A. J.; Prinn, R. G.

2014-09-01

111

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

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

112

Carbon dioxide emission implications if hydrofluorocarbons are regulated: a refrigeration case study.  

PubMed

The U.S. is strongly considering regulating hydrofluorocarbons (HFCs) due to their global climate change forcing effects. A drop-in replacement hydrofluoroether has been evaluated using a gate-to-grave life cycle assessment of greenhouse gas emissions for the trade-offs between direct and indirect carbon dioxide equivalent emissions compared to a current HFC and a historically used refrigerant. The results indicate current regulations being considered may increase global climate change. PMID:20050659

Blowers, Paul; Lownsbury, James M

2010-03-01

113

Refrigeration Servicing.  

ERIC Educational Resources Information Center

This self-study course is designed to familiarize Marine enlisted personnel with the services required to be performed on refrigeration equipment. The course contains four study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the unit. The study units are divided into numbered work…

Hamilton, Donald L.; And Others

114

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

SciTech Connect

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.

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

115

46 CFR 151.50-79 - Methyl acetylene-propadiene mixture.  

Code of Federal Regulations, 2010 CFR

...acetylene-propadiene mixture must have a refrigeration system that does not compress the cargo vapor or have a refrigeration system with the following features...piping system, including the cargo refrigeration system, for tanks to be...

2010-10-01

116

Refrigerant piping  

SciTech Connect

The piping design of an air conditioning system is a critical element in the proper performance of the system. It involves an extremely complex relationship in the flow of refrigerant oil through the various parts of the system. The factor that must be considered in a piping design are the inter-relationships between velocity, pressure, friction and density, as well as the related variables required for proper fluid flow. These variables and relationships can be expressed in long mathematical equations, performance charts, and pressure drop tables for fluid flow through the piping. The improper design and sizing of refrigerant piping in a sealed system may result in loss of system efficiency that could lead to a los of overall system capacity as well as eventual failure of components of the system.

Puzio, H. [Sussex County Vocational Technical School, Sparta, NJ (United States)

1996-10-01

117

Fluorescent refrigeration  

DOEpatents

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.

Epstein, Richard I. (Santa Fe, NM); Edwards, Bradley C. (Los Alamos, NM); Buchwald, Melvin I. (Santa Fe, NM); Gosnell, Timothy R. (Santa Fe, NM)

1995-01-01

118

Magnetic Refrigeration Development  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

119

NEW CHEMICAL ALTERNATIVE FOR OZONE-DEPLETING SUBSTANCES: HFC-245CA  

EPA Science Inventory

The report gives results of a preliminary evaluation of a new hydrofluorocarbon (HFC) -- HFC-245ca or 1,1,2,2,3-pentafluoropropane -- as a possible alternative for chlorofluorocarbon (CFC)-11 (trichlorofluoromethane) and hydrochlorofluorocarbon (HCFC)-123 (1,1,1-trifluoro-2,2-dic...

120

EVALUATION OF HFC-245FA AS A POTENTIAL ALTERNATIVE FOR CFC-11 IN LOW PRESSURE CHILLERS  

EPA Science Inventory

The paper reports results of an evaluation of HFC-245fa as a potential alternative for CFC-11 in low pressure chillers. (NOTE: It was reported previously that HFC245ca (1,1,2,2,3-pentafluoro-propane) has many attributes that make it an attractive candidate alternative for CFC-11 ...

121

Refrigerant pressurization system with a two-phase condensing ejector  

DOEpatents

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.

Bergander, Mark (Madison, CT)

2009-07-14

122

Evaluated rate constants for selected HCFC's and HFC's with OH and O((sup)1D)  

NASA Technical Reports Server (NTRS)

The chemistry of HCFC's and HFC's in the troposphere is controlled by reactions with OH in which a hydrogen atom is abstracted from the halocarbon to form water and a halo-alkyl radical. The halo-alkyl radical subsequently reacts with molecular oxygen to form a peroxy radical. The reactions of HCFC's and HFC's with O(exp1D) atoms are unimportant in the troposphere, but may be important in producing active chlorine of OH in the stratosphere. Here, the rate constants for the reactions of OH and O(exp1D) with many HFC's and HCFC's are evaluated. Recommendations are given for the five HCFC's and three HFC's specified by AFEAS as primary alternatives as well as for all other isomers of C1 and C2 HCFC's and HFC's where rate data exist. In addition, recommendations are included for CH3CCl3, CH2Cl2, and CH4.

Hampson, Robert F.; Kurylo, Michael J.; Sander, Stanley P.

1990-01-01

123

Refrigerant directly cooled capacitors  

DOEpatents

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

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

2007-09-11

124

Fluorescent refrigeration  

DOEpatents

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.

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

1995-09-05

125

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

SciTech Connect

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.

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

1998-11-01

126

Refrigeration system  

SciTech Connect

This patent describes a chamber including an expandable refrigerant system associated therewith. The system comprises reservoir containing an expandable refrigerant coolant and lead piping connecting the reservoir to conduits carrying the coolant therein. The chamber comprises top, bottom and side walls, accordingly defining an interior and an exterior to the chamber, one of the walls comprises a door affording access into the chamber, each of the walls being insulated with insulating material. At least one of the walls comprises a first layer of the insulating material extending thereover adjacent the exterior and a second layer of the insulating material extending thereover adjacent the interior. The reservoir, lead piping and conduits are disposed intermediate the first and second layers of insulating material thereby isolating them from both the interior and exterior. Heat transferring through the at least one wall is substantially absorbed by the coolant and the insulating material cooled by the coolant, before it is able to penetrate through the at least one wall, permitting a product placed in the chamber to effectively maintain or substantially maintain a selected even temperature.

Pagani, R.F.; Clarke, K.J.; Avon, E.J.

1986-11-11

127

REACH. Refrigeration Units.  

ERIC Educational Resources Information Center

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

Snow, Rufus; And Others

128

Stirling Refrigerator  

NASA Astrophysics Data System (ADS)

A Stirling cooler (refrigerator) was proposed in 1862 and the first Stirling cooler was put on market in 1955. Since then, many Stirling coolers have been developed and marketed as cryocoolers. Recently, Stirling cycle machines for heating and cooling at near-ambient temperatures between 173 and 400K, are recognized as promising candidates for alternative system which are more compatible with people and the Earth. The ideal cycles of Stirling cycle machine offer the highest thermal efficiencies and the working fluids do not cause serious environmental problems of ozone depletion and global warming. In this review, the basic thermodynamics of Stirling cycle are briefly described to quantify the attractive cycle performance. The fundamentals to realize actual Stirling coolers and heat pumps are introduced in detail. The current status of the Stirling cycle machine technologies is reviewed. Some machines have almost achieved the target performance. Also, duplex-Stirling-cycle and Vuilleumier-cycle machines and their performance are introduced.

Kagawa, Noboru

129

ARTI refrigerant database  

SciTech Connect

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilities 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.

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

1999-01-01

130

ARTI refrigerant database  

SciTech Connect

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.

Calm, J.M.

1996-11-15

131

ARTI refrigerant database  

SciTech Connect

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.

Calm, J.M.

1996-07-01

132

ARTI refrigerant database  

SciTech Connect

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.

Calm, J.M.

1996-01-15

133

Microminiature Refrigeration  

NASA Astrophysics Data System (ADS)

The dramatic growth of industrial cryogenics in the past century has overshadowed the need for cryogenics on a smaller scale. Today, small scale, MEMS or microminiature refrigerators constitute a small part of the field, but one with a unique role to play, often in instrumentation. Key attributes of these coolers have proved to be their small size, low noise, fast response, and low cost. The small size has enabled the integration of the instrument and cooler. The fast response and low noise have made possible instruments of unique capabilities. Opportunities exist for the seamless integration of cryogenics in other products, but to succeed here, companies need strength in both cryogenics and a broad range of other disciplines, including materials science, electronics, and software. To offset economies of scale, new fabrication technologies have had to be created, and others are needed. Some key elements remain to be developed before more widespread use of this technology will be seen. Better miniature heat exchangers and regenerators are needed. Development of miniature compressors to power the coolers could herald a new world of cooled devices analogous to the revolution created by fractional horsepower electric motors in the past fifty years. Opportunities abound!

Little, W. A.

2008-03-01

134

Historical emissions of HFC-23 (CHF3) in China and projections upon policy options by 2050.  

PubMed

Trifluoromethane (CHF3, HFC-23) is one of the hydrofluorocarbons (HFCs) regulated under the Kyoto Protocol with a global warming potential (GWP) of 14?800 (100-year). China's past, present, and future HFC-23 emissions are of considerable interest to researchers and policymakers involved in climate change. In this study, we compiled a comprehensive historical inventory (1980-2012) and a projection (2013-2050) of HFC-23 production, abatements, and emissions in China. Results show that HFC-23 production in China increased from 0.08 ± 0.05 Gg/yr in 1980 to 15.4 ± 2.1 Gg/yr (228 ± 31 Tg/yr CO2-eq) in 2012, while actual HFC-23 emissions reached a peak of 10.5 ± 1.8 Gg/yr (155 ± 27 Tg/y CO2-eq) in 2006, and decreased to a minimum of 7.3 ± 1.3 Gg/yr (108 ± 19 Tg/yr CO2-eq) in 2008 and 2009. Under the examined business-as-usual (BAU) scenario, the cumulative emissions of HFC-23 in China over the period 2013-2050 are projected to be 609 Gg (9015 Tg CO2-eq which approximates China's 2012 CO2 emissions). Currently, China's annual HFC-23 emissions are much higher than those from the developed countries, while it is estimated that by year 2027, China's historic contribution to the global atmospheric burden of HFC-23 will have surpassed that of the developed nations under the BAU scenario. PMID:24605818

Fang, Xuekun; Miller, Benjamin R; Su, Shenshen; Wu, Jing; Zhang, Jianbo; Hu, Jianxin

2014-04-01

135

Influence of Oil on Refrigerant Evaporator Performance  

NASA Astrophysics Data System (ADS)

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%.

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

136

Refrigeration for Cryogenic Sensors  

NASA Technical Reports Server (NTRS)

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.

Gasser, M. G. (editor)

1983-01-01

137

New Rules for Refrigerants.  

ERIC Educational Resources Information Center

Discusses how educational facilities can comply with new Environmental Protection Agency regulations regarding commercial refrigerants. Tips include developing a compliance plan with a manager in charge of it, and developing an accurate and complete refrigerant-systems assessment. (GR)

Jackson, Robert

1999-01-01

138

A New Functional Form and New Fitting Techniques for Equations of State with Application to Pentafluoroethane ,,HFC-125...  

E-print Network

; thermodynamic properties. Contents List of Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 to Pentafluoroethane ,,HFC-125... Eric W. Lemmona... Physical and Chemical Properties Division, National Institute

139

Development of Magnetic Refrigerator  

NASA Astrophysics Data System (ADS)

A series of R & D of magnetic refrigerators has been done in order to realize an advanced type cryocooler for superconducting magnets of maglev trains and MRI medical system. As a result of efforts on both the magnetic refrigerator and superconducting magnets, a parasitic type magnetic refrigeration system was proposed.

Ogiwara, Hiroyasu; Nakagome, Hideki; Kuriyama, Tohru

140

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,...

141

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

142

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

143

HFC-23 (CHF3) emission trend response to HCFC-22 (CHClF2) production and recent HFC-23 emission abatement measures  

E-print Network

HFC-23 (also known as CHF3 [CHF subscript 3], fluoroform or trifluoromethane) is a potent greenhouse gas (GHG), with a global warming potential (GWP) of 14 800 for a 100-year time horizon. It is an unavoidable by-product ...

Miller, B. R.

144

A Study of TCP Dynamics over HFC Networks New broadband access technologies such as Hybrid Fiber Coaxial (HFC) are likely to provide fast and cost effective sup-  

E-print Network

of applications including Video on demand (VoD), interactive computer games, and internet-type applications performance and show, by means of analysis and simulation, the performance degradation of TCP (Reno), due and the propagation delay. However, in the case of multiple access media, such as HFC, it is important to study

145

Construction and performance of a thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

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 data, and the gas-control panel which is used to fill and purge the system and to prepare gas mixtures. The system is assembled and the first measurements show a good behavior. A low temperature of -65 °C is achieved which is one of the lowest reported temperatures up to date.

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

2002-01-01

146

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)

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.

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

2008-12-01

147

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

SciTech Connect

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.

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

2012-01-01

148

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

Microsoft Academic Search

The partly halogenated Câ-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

Armin Jordan; Hartmut Frank

1999-01-01

149

ARTI refrigerant database  

SciTech Connect

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

Calm, J.M.

1997-02-01

150

ARTI refrigerant database  

SciTech Connect

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 manufactures and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on many refrigerants including propane, ammonia, water, carbon dioxide, propylene, ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.

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

1998-08-01

151

On-road performance analysis of R134a\\/R600a\\/R290 refrigerant mixture in an automobile air-conditioning system with mineral oil as lubricant  

Microsoft Academic Search

R134a has been accepted as the single major refrigerant in the automobile industry and it has been used worldwide. But, the problem associated with it is the use of the PAG oil as the lubricant. Unlike the conventional mineral oil, the synthetic PAG oil used with R134a is highly hygroscopic in nature. The PAG lubricants come with different additives unique

T. S. Ravikumar; D. Mohan Lal

2009-01-01

152

Waste Heat Recovery from Refrigeration  

E-print Network

-product of the refrigeration cycle becomes economically justifiable. This paper treats the history of the refrigeration machine, and the modern developments which have made available the system concept of waste heat recovery from refrigeration. A typical application...

Jackson, H. Z.

1982-01-01

153

Chemically assisted mechanical refrigeration process  

DOEpatents

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.

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

1987-01-01

154

Chemically assisted mechanical refrigeration process  

DOEpatents

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.

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

1987-01-01

155

Chemically assisted mechanical refrigeration process  

DOEpatents

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

Vobach, A.R.

1987-11-24

156

Chemically assisted mechanical refrigeration process  

DOEpatents

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

Vobach, A.R.

1987-06-23

157

Selection of the most suitable refrigerant for a shell and tube condenser  

NASA Astrophysics Data System (ADS)

A theoretical performance study on a shell and tube condenser with various refrigerant blends was conducted for various ratios proposed by other researchers in the literature. The theoretical results showed that all of the alternative refrigerants investigated in the analysis have a slightly lower convective heat transfer coefficient than their base refrigerants. The refrigerant mixture of R290/R600, R152a/R125/R32 and R32/R134a were found to be the most proper replacement refrigerant among the alternatives.

Dalkilic, A. S.; Mahian, O.; Wongwises, S.

2014-02-01

158

Theory of cascade refrigeration  

NASA Astrophysics Data System (ADS)

The maximum difference between the warm and cold temperature of a refrigeration cycle is limited by properties of the refrigerant and/or losses associated with the transport of the refrigerant. For larger temperature differences, one has to arrange several refrigeration cycles "above" each other, each cycle spanning a certain temperature difference. This approach is called cascade refrigeration and has played an important role in the history of cryogenics. For a theory of cascade refrigeration it is helpful to define a general one-stage non-reversible refrigeration step and to visualize it within the temperature-entropy diagram. Then one can combine several one-stage cycles to a cascade. There exist two types of cascades: "Full" cascades, where all entropy gains of a lower stage are transferred to the next higher temperature stage, and "partial" cascades, where each single cycle goes up to ambient temperature, where a part of the entropy gain is removed, and only the rest of the entropy gain is transferred to the next higher temperature stage. In cryogenic refrigeration "partial" cascades are generally more efficient than "full" cascades.

Quack, Hans H.

2012-06-01

159

Evidence for under-reported western European emissions of the potent greenhouse gas HFC-23  

NASA Astrophysics Data System (ADS)

Western European emission inventories of the potent greenhouse gas trifluoromethane (HFC-23) are validated at a country level by combining 2-hourly atmospheric in-situ measurements at Jungfraujoch (Switzerland) and Mace Head (Ireland) with Lagrangian transport simulations. HFC-23 has an atmospheric lifetime of ˜270 yr and a 100-yr global warming potential (GWP) of 14,800 and is unintentionally produced during the manufacture of chlorodifluoromethane (HCFC-22). For the study region we derive emissions of 144-216 Mg/yr for July 2008-July 2010, which are 60-140% higher than the official emissions gathered from the national reports for the year 2009. The largest discrepancy is found for Italy, where our estimate of 26-56 Mg/yr exceeds the national inventory (2.6 Mg/yr) by more than an order of magnitude. These findings suggest that non-reported emissions from Annex 1 countries partly explain the recently derived gap between global bottom-up and top-down HFC-23 emission estimates. The results presented here provide independent information to relevant authorities on effective reporting of HFC-23 emissions, and demonstrate the potential of atmospheric measurements for real-world verification of greenhouse gas emissions.

Keller, Christoph A.; Brunner, Dominik; Henne, Stephan; Vollmer, Martin K.; O'Doherty, Simon; Reimann, Stefan

2011-08-01

160

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

PubMed

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

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

2012-02-01

161

Selected Vuilleumier refrigerator performance characteristics  

NASA Technical Reports Server (NTRS)

Study of the performance characteristics of the Vuilleumier refrigerator for spacecraft applications. The effect on refrigerator performance of several important components and design parameters is examined. The components and design parameters selected for investigation include the cold-end heat conductance, cold regenerator, refrigerator rpm, and refrigerator sump temperature.

Sherman, A.

1973-01-01

162

Magnetic refrigeration for space applications  

SciTech Connect

Magnetic refrigeration is briefly analyzed and thermodynamically compared to gas refrigeration. The characteristics of magnetic refrigerators with respect to spacecraft applications are discussed and indicate that high reliability coupled with high efficiency is possible. The latest experimental results on several wheel and reciprocating magnetic refrigerators are summarized.

Barclay, J.A.; Steyert, W.A.

1980-01-01

163

PERFORMANCE OF HC AND HFC REFRIGERANTS IN A FINNED-TUBE EVAPORATOR AND ITS EFFECT ON SYSTEM EFFICIENCY  

Microsoft Academic Search

The paper presents a comparable evaluation of isobutane (R600a), propane (R290), R134a, R22, R410A, and R32 in a n optimized finned-tube evaporator, and analyzes the impact of evaporator effects on the system coefficient of performance (COP). The study relied on a detailed evaporator model derived from NIST's EVAP-COND simulation package and used the ISHED1 scheme employing a non -Darwinian Learnable

M. Kim

164

Thermoacoustic engines and refrigerators  

SciTech Connect

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}.

Swift, G.

1996-12-31

165

DOE/AHAM advanced refrigerator technology development project  

SciTech Connect

As part of the effort to improve residential energy efficiency and reduce greenhouse emissions from power plants, several design options were investigated for improving the energy efficiency of a conventionally designed domestic refrigerator-freezer. The program goal was to reduce the energy consumption of a 20-ft{sup 3} (570-L) top-mount refrigerator-freeze to 1.00 kWh/d, a 50% reduction from the 1993 National Appliance Energy Conservation Act (NAECA) standard. The options--such as improved cabinet and door insulation, a high-efficiency compressor, a low-wattage fan, a large counterflow evaporator, and adaptive defrost control--were incorporated into prototype refrigerator-freezer cabinets and refrigeration systems. The refrigerant HFC-134a was used as a replacement for CFC-12. The baseline energy performance of the production refrigerator-freezers, along with cabinet heat load and compressor calorimeter test results, were extensively documented to provide a firm basis for experimentally measured energy savings. The project consisted of three main phases: (1) an evaluation of energy-efficient design options using computer simulation models and experimental testing, (2) design and testing of an initial prototype unit, and (3) energy and economic analyses of a final prototype. The final prototype achieved an energy consumption level of 0.93 kWh/d--an improvement of 45% over the baseline unit and 54% over the 1993 NAECA standard for 20-fg{sup 3} (570-L) units. The manufacturer`s cost for those improvements was estimated at $134; assuming that cost is doubled for the consumer, it would take about 11.4 years to pay for the design changes. Since the payback period was thought to be unfeasible, a second, more cost-effective design was also tested. Its energy consumption level was 1.16 kWh/d, a 42% energy savings, at a manufacturer`s cost increase of $53. Again assuming a 100% markup, the payback for this unit would be 6.6 years.

Vineyard, E.A.; Sand, J.R.; Rice, C.K.; Linkous, R.L.; Hardin, C.V.; Bohman, R.H.

1997-03-01

166

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

Microsoft Academic Search

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,

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

2000-01-01

167

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

Microsoft Academic Search

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

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

1995-01-01

168

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

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

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

2013-01-01

169

46 CFR 154.702 - Refrigerated carriage.  

Code of Federal Regulations, 2010 CFR

...Refrigerated carriage. (a) Each refrigeration system must: (1) Have...to the capacity of the largest refrigeration unit in the system. (b) For the purpose of this section, a “refrigeration unit” includes a...

2010-10-01

170

Determination of a vapor compression refrigeration system refrigerant charge  

NASA Astrophysics Data System (ADS)

A physical model is established in this paper to describe the heat transfer and two phase flow of a refrigerant in the evaporator and condenser of a vapor compression refrigeration system. The model is then used to determine the refrigerant charge in vapor compression units. The model is used for a sensitivity analysis to determine the effect that varing design parameters on the refrigerant charge. The model is also used to evaluate the effect of refrigerant charge and the thermal physical properties on the refrigeration cycle. The predicted value of the refrigerant charge and experimental data agree well. The model and the method presented in this paper could be used to design vapour compression units such as domestic refrigerators and air conditioners.

Yang, Chun-Xin; Dang, Chao-Bin

1995-09-01

171

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)

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.

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

172

ARTI Refrigerant Database  

NASA Astrophysics Data System (ADS)

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.

Cain, J. M.

1993-04-01

173

ARTI Refrigerant Database  

NASA Astrophysics Data System (ADS)

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.

Calm, J. M.

1993-11-01

174

ARTI Refrigerant Database  

SciTech Connect

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.

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

1993-04-30

175

Adsorption Refrigeration System  

SciTech Connect

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.

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

2011-01-01

176

Evaluation of design options for improving the energy efficiency of an environmentally safe domestic refrigerator-freezer  

SciTech Connect

In order to reduce greenhouse emissions from power plants and respond to regulatory actions arising from the National Appliance Energy Conservation Act (NAECA), several design options were investigated for improving the energy efficiency of a conventionally designed, domestic refrigerator-freezer. The options, such as improved cabinet insulation and high-efficiency compressor and fans, were incorporated into a prototype refrigerator-freezer cabinet and refrigeration system to produce a unit that is superior from an environmental viewpoint due to its lower energy consumption and the use of refrigerant HFC-134a as a replacement for CFC-12. Baseline energy performance of the original 1993 production refrigerator-freezer, along with cabinet heat load and compressor calorimeter test results, were extensively documented to provide a firm basis for experimentally measured energy savings. A detailed refrigerator system computer model was used to evaluate the energy savings for several design modifications that, collectively, could achieve a targeted energy consumption of 1.00 kWh/d for a 20 ft{sup 3} (570 l) top-mount, automatic-defrost, refrigerator-freezer. The energy consumption goal represents a 50% reduction in the 1993 NAECA standard for units of this size. Following the modeling simulation, laboratory prototypes were fabricated and tested to experimentally verify the analytical results and aid in improving the model in those areas where discrepancies occurred. While the 1.00 kWh/d goal was not achieved with the modifications, a substantial energy efficiency improvement of 22% (1.41 kWh/d) was demonstrated using near-term technologies. It is noted that each improvement exacts a penalty in terms of increased cost or system complexity/reliability. Further work on this project will analyze cost-effectiveness of the design changes and investigate alternative, more-elaborate, refrigeration system changes to further reduce energy consumption.

Vineyard, E.A.; Sand, J.R. [Oak Ridge National Lab., TN (United States); Bohman, R.H.

1995-03-01

177

Save with Hybrid Refrigeration  

E-print Network

the possibility of ammonium carbamate formation caused by air leakage. In order to prOVide a -45?F refrigeration, an AAR unit requires a higher temperature heat source at higher value levels would reduce recovery of low cost waste heat from process streams... the possibility of ammonium carbamate formation caused by air leakage. In order to prOVide a -45?F refrigeration, an AAR unit requires a higher temperature heat source at higher value levels would reduce recovery of low cost waste heat from process streams...

Chung, C. W.

178

Variable Refrigerant Flow HVAC  

E-print Network

Variable refrigerant flow technology HVAC CATEE 2013 San Antonio, TX ESL-KT-13-12-33 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16-18 What is the acronym VRF? ? Variable Refrigerant Flow Operates like a... heat pump utilizing VFD Inverter Compressors and LEV’s Unlike conventional commercial and residential HVAC systems in the USA The predominate method of cooling and heating in the world ESL-KT-13-12-33 CATEE 2013: Clean Air Through Energy Efficiency...

Jones, S.

2013-01-01

179

Helium dilution refrigeration  

E-print Network

. The refrigerator was then leak tested on a Veeco NS-9 Helium Leak Detector. A small leak was found at the capillary joint between the still and mixing cham'oer and repaired. No other leaks were detectable on the most sensitive scale of the detector. 6.... The refrigerator was then leak tested on a Veeco NS-9 Helium Leak Detector. A small leak was found at the capillary joint between the still and mixing cham'oer and repaired. No other leaks were detectable on the most sensitive scale of the detector. 6...

McKee, Thomas Raymond

2012-06-07

180

Low-temperature magnetic refrigerator  

DOEpatents

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.

Barclay, J.A.

1983-05-26

181

Status Of Sorption Cryogenic Refrigeration  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.

1988-01-01

182

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...

183

COLD STORAGE DESIGN REFRIGERATION EQUIPMENT  

E-print Network

of each section-1 This leaflet is part one of a series of five to be prepared within the broader overallCOLD STORAGE DESIGN AND REFRIGERATION EQUIPMENT REFRIGERATION OF FISH - PART 1 \\ "..\\- ,,, T I Fishery Leaflet 427 Washington 25, D. C. June 1956 REFRIGERATION OF FISH - PART em; COlD STORAGE DESIGN

184

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

SciTech Connect

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.

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

2014-01-01

185

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

186

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

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Definitions concerning commercial refrigerators, freezers and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2011-01-01

187

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

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Definitions concerning commercial refrigerators, freezers and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2012-01-01

188

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

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Definitions concerning commercial refrigerators, freezers and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2013-01-01

189

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

...2014-01-01 false Definitions concerning commercial refrigerators, freezers and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2014-01-01

190

Multilayer Thermionic Refrigeration  

Microsoft Academic Search

A new method of refrigeration is proposed. Efficient cooling is obtained by thermionic emission of electrons over Schottky barriers between metals and semiconductors. Since the barriers have to be thin, each barrier can have only a small temperature difference (â¼1 K) . Macroscopic cooling is obtained with a multilayer device. The same device is also an efficient generator of electrical

G. D. Mahan; L. M. Woods

1998-01-01

191

Multilayer thermionic refrigeration  

Microsoft Academic Search

A review is presented of our program to construct an efficient solid state refrigerator based on thermionic emission of electrons over periodic barriers in the solid. The experimental program is to construct a simple device with one barrier layer using a three layers: metal-semiconductor-metal. The theoretical program is doing calculations to determine: (i) the optimal layer thickness, and (ii) the

G. D. Mahan

1999-01-01

192

Improved cryogenic refrigeration system  

NASA Technical Reports Server (NTRS)

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.

Higa, W. H.

1967-01-01

193

Fundamentals of Refrigeration.  

ERIC Educational Resources Information Center

This self-study course is designed to familiarize Marine enlisted personnel with the principles of the refrigeration process. The course contains five study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the unit. The study units are divided into numbered work units, each…

Sutliff, Ronald D.; And Others

194

Solar Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

195

Plant Site Refrigeration Upgrade  

E-print Network

an outdated, energy inefficient, CFC based system that was unreliable and expensive to operate. The installation of the direct compression ammonia Refrigeration System resulted in energy savings of 64.8% and reduced electric costs by more than $600,000 per...

Zdrojewski, R.; Healy, M.; Ramsey, J.

196

Modeling phase equilibria in mixtures containing hydrogen fluoride and halocarbons  

Microsoft Academic Search

Recently, much attention has been focused on the production of environmentally acceptable refrigerants, which not only offer desirable physico-chemical properties, but do not deplete the ozone layer and do not cause the greenhouse effect. The production of such refrigerants involves the separation of multicomponent mixtures containing hydrogen fluoride, hydrogen chloride, and various chlorinated and fluorinated hydrocarbons. Therefore, it is indispensable

M. Lencka; Andrzej Anderko

1993-01-01

197

Dilution refrigeration for space applications  

NASA Technical Reports Server (NTRS)

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

Israelsson, U. E.; Petrac, D.

1990-01-01

198

Step piston pulse tube refrigerator  

NASA Astrophysics Data System (ADS)

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.

Zhu, Shaowei

2014-11-01

199

Evaluation of volatile compounds and free fatty acids in set types yogurts made of ewes’, goats’ milk and their mixture using two different commercial starter cultures during refrigerated storage  

Microsoft Academic Search

Six different types of yogurt were manufactured from Damascus goat milk, Awassi ewe milk and a mixture of equal portions of the 2 species of milk using 2 types of commercial yogurt cultures (CH-1 and YF-3331). Yogurts were chemically analysed at 1, 7, 14 and 21days of storage. Results showed that cultures significantly affected acetaldehyde (P<0.05), acetone (P<0.05) and diacetyl

Zehra Güler; Alev Canan Gürsoy-Balc?

2011-01-01

200

Initial parametric results using CYCLEZ: A LMTD-specified, Lorenz-Meutzner cycle refrigerator-freezer model  

Microsoft Academic Search

A computer model representing a two-evaporator, two-intercooler refrigerator-freezer operating at steady-state with nonazeotropic refrigerant mixtures (CYCLEZ) has been developed at Oak Ridge National Laboratory (ORNL). This model is being used to assess the effects of system design and operating parameters on the cycle performance of a refrigerator-freezer designed around the Lorenz-Meutzner (L-M) circuit. Separate evaporators for the freezer and fresh-food

C. Keith Rice; James R. Sand

1990-01-01

201

16 CFR Appendix A2 to Part 305 - Refrigerators and Refrigerators-Freezers With Manual Defrost  

Code of Federal Regulations, 2013 CFR

...false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2 to Part 305 Commercial Practices FEDERAL...305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range Information Manufacturer's Rated Total...

2013-01-01

202

16 CFR Appendix A2 to Part 305 - Refrigerators and Refrigerators-Freezers With Manual Defrost  

Code of Federal Regulations, 2012 CFR

...false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2 to Part 305 Commercial Practices FEDERAL...305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range Information Manufacturer's Rated Total...

2012-01-01

203

16 CFR Appendix A2 to Part 305 - Refrigerators and Refrigerators-Freezers With Manual Defrost  

Code of Federal Regulations, 2011 CFR

...false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2 to Part 305 Commercial Practices FEDERAL...305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range Information Manufacturer's Rated Total...

2011-01-01

204

16 CFR Appendix A2 to Part 305 - Refrigerators and Refrigerators-Freezers With Manual Defrost  

...false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2 to Part 305 Commercial Practices FEDERAL...305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range Information Manufacturer's Rated Total...

2014-01-01

205

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

Code of Federal Regulations, 2010 CFR

...refrigerator, freezer, and refrigerator-freezer means refrigeration equipment that— (1) Is not a consumer product (as defined...Holding temperature application means a use of commercial refrigeration equipment other than a pull-down temperature...

2010-01-01

206

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material  

DOEpatents

A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

Barclay, John A. (Madison, WI); Stewart, Walter F. (Marshall, WI); Henke, Michael D. (Los Alamos, NM); Kalash, Kenneth E. (Los Alamos, NM)

1987-01-01

207

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material  

DOEpatents

A magnetic refrigerator operating in the 12 to 77 K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

Barclay, J.A.; Stewart, W.F.; Henke, M.D.; Kalash, K.E.

1986-04-03

208

Space helium refrigerator  

NASA Astrophysics Data System (ADS)

Design studies and flight tests of an automatic closed-cycle three-cascade helium refrigerator are presented. Intended for cooling submillimeter telescope detectors to 4.4 K on the orbital station Salyut-6, the cryogenic system is based on the Joule-Thomson cooling effect, with two gas cooling machines operating under the Stirling cycle for preliminary cooling levels of 80 K and 20 K. Power requirements are less than 1.5 kW, while providing useful refrigeration of 0.5 W. Results of two years of flight tests indicate successful operation, including the merits of high accuracy and stability in maintaining operation temperature, short cool-down period, high efficiency, reliability and simplicity of operation.

Salomonovich, A. E.; Sidiakina, T. M.; Khaikin, A. S.; Bakun, V. N.; Nikonov, A. A.; Maslakov, V. A.; Klimenko, E. I.; Kurkin, V. N.

1981-08-01

209

Compact acoustic refrigerator  

DOEpatents

A compact acoustic refrigeration system 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. 18 figs.

Bennett, G.A.

1992-11-24

210

Superfluid thermodynamic cycle refrigerator  

DOEpatents

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.

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

1992-12-22

211

Compact acoustic refrigerator  

DOEpatents

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.

Bennett, Gloria A. (Los Alamos, NM)

1992-01-01

212

Superfluid thermodynamic cycle refrigerator  

DOEpatents

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.

Swift, Gregory W. (Santa Fe, NM); Kotsubo, Vincent Y. (La Canada, CA)

1992-01-01

213

Vaccine refrigerator testing. Final report  

SciTech Connect

For the Central American Health Clinic Project initiated in 1986, Sandia National Laboratories and the Florida Solar Energy Center recognized the need for a test and evaluation program for vaccine refrigeration systems. At the Florida Solar Energy Center, side-by-side testing of three photovoltaic powered vaccine refrigerators began in 1987. The testing was expanded in 1988 to include a kerosene absorption refrigerator. This report presents observations, conclusions, and recommendations derived from testing the four vaccine refrigeration systems. Information is presented pertaining to the refrigerators, photovoltaic arrays, battery subsystems, charge controllers, and user requirements. This report should be of interest to designers, manufacturers, installers, and users of photovoltaic-powered vaccine refrigeration systems and components.

Ventre, G.G. [Univ. of Central Florida, Orlando, FL (United States); Kilfoyle, D.; Marion, B. [Florida Solar Energy Center, Cape Canaveral, FL (United States)

1990-06-01

214

Japanese activities in refrigeration technology  

NASA Astrophysics Data System (ADS)

This paper reviews recent activities in refrigeration technology in Japan. The projects described are stimulated by growing industrial needs or form part of large national projects. The JNR project on the MAGLEV train is currently the most powerful activity and it demands knowledge in all the different disciplines of cryogenics in particular on various scales of refrigeration. Research activities are also directed towards the development of Stirling cycle and magnetic refrigerators for applications in a wider area.

Fujita, T.; Ohtsuka, T.; Ishizaki, Y.

215

NICE3: Industrial Refrigeration System  

SciTech Connect

Energy Concepts has developed an absorption-augmented system as a cost-effective means of achieving more cooling capacity with a substantial reduction in energy consumption and greenhouse gas emissions for industrial refrigeration. It cuts fuel consumption by 30% by combining an internal combustion engine with a mechanical compression refrigeration system and an absorption refrigeration system. The absorption system is powered by engine waste heat. Conventional industrial refrigeration uses mechanical vapor compression, powered by electric motors, which results in higher energy costs. By the year 2010, the new system could cut fuel consumption by 19 trillion Btu and greenhouse emissions by more than 1 million tons per year.

Simon, P.

1999-09-29

216

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 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...

2012-10-01

217

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2011 CFR

...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...

2011-10-01

218

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 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...

2013-10-01

219

PERFORMANCE TESTING OF A SEMI-HERMETIC COMPRESSOR WITH HFC-236EA AND CFC-114 AT CHILLER CONDITIONS  

EPA Science Inventory

The paper gives results of tests of both HFC-236ea and CFC-114 at a range of temperatures covering surface craft and submarine chiller conditions. vaporating temperatures ranged from 1.7 to 12.8 C, and condensing temperatures from 40.6 to 65.6 C, in order to develop a nine-point ...

220

The refrigerator revolution  

SciTech Connect

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.

Ayres, E.; French, H.

1996-09-01

221

He dilution refrigerator  

NASA Astrophysics Data System (ADS)

We describe the preparation of ultracold atomic clouds in a dilution refrigerator. The closed-cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultrahigh vacuum conditions. The presented system is a step toward the creation of a quantum hybrid system combining ultracold atoms and solid-state quantum devices.

Jessen, F.; Knufinke, M.; Bell, S. C.; Vergien, P.; Hattermann, H.; Weiss, P.; Rudolph, M.; Reinschmidt, M.; Meyer, K.; Gaber, T.; Cano, D.; Günther, A.; Bernon, S.; Koelle, D.; Kleiner, R.; Fortágh, J.

2014-09-01

222

Sun synchronous solar refrigeration  

NASA Astrophysics Data System (ADS)

The primary goal of this project was to prototype a complete Sun Synchronous Solar Powered Refrigerator. The key element to the technology is the development of the hermetic motor compressor assembly. The prototype was to be developed to either the stage where Polar Products could receive additional venture capital or to the point whereby Polar could use their own capital to manufacture the systems. Our goal was to construct a prototype which would be the next step to a proven and market ready product. To demonstrate the technology under laboratory conditions was a very minimal goal.

223

Heat recovery from refrigeration systems  

Microsoft Academic Search

There are many very complicated methods on the market of recovering waste heat from refrigeration systems. Most are based on a particular manufacturer's product. Most result in having to run the refrigeration system at higher than necessary condensing conditions, wasting rather than conserving energy. Through the techniques shown above with the use of very common components, multiple condenser systems can

Stamm

1982-01-01

224

Performances of the mixed-gases Joule-Thomson refrigeration cycles for cooling fixed-temperature heat loads  

NASA Astrophysics Data System (ADS)

Numerous mixed-gases refrigeration cycle configurations based on Joule-Thomson effects were developed in the past several decades. In this paper, comprehensive thermodynamic analyses were made on two typical cycle configurations to learn their performance for cooling fixed-temperature heat loads. One is the single-stage cycle without phase separators; the other is the auto-cascade refrigeration cycle which has at least one phase separator. An exergy model was developed to analyze the thermodynamic performance of those refrigeration cycles. Comprehensive comparisons were made on the performance of the recuperative throttling cycles using multicomponent mixture as refrigerant, including extensive simulations and optimizations of mixtures and cycle configurations. The results show that the auto-cascade cycle can improve thermodynamic performance in the case of using mixtures with increased fraction of high-boiling components, however, degrade the performance when using mixtures with increased fraction of low-boiling components. The results also show that the mixed refrigerant is the most important designing parameter in the design of such mixed-gases refrigeration system. Different cycle configuration has different optimal mixture composition. When using optimal mixtures, both cycles (separation and non-separation) can provide approximately equal performance.

Gong, M. Q.; Wu, J. F.; Luo, E. G.

2004-12-01

225

Helium dilution refrigeration system  

DOEpatents

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

Roach, P.R.; Gray, K.E.

1988-09-13

226

Helium dilution refrigeration system  

DOEpatents

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

Roach, Patrick R. (Darien, IL); Gray, Kenneth E. (Naperville, IL)

1988-01-01

227

Transient phenomena initiating phase transition in dilution refrigerator  

NASA Astrophysics Data System (ADS)

We have analysed the transient processes in a Dilution Refrigerator (DR) leading to phase separation of 3He-4He mixture into concentrated and dilute solutions using an extended SIDFO (Simulation of Integrated Dilution refrigerator For Optimisation) Pradhan et al. (2013) analysis tool. The evolution of the phase separation interface along the concentrated channel and its arrival in the mixing chamber for a given physical situation has been thoroughly examined. The significance of the 3He/4He composition in the mixer, the flow rate and the still power on the phase separation is presented here. The consequences of several relevant thermodynamic parameters and the composition of isotopic mixture for successful function of the DR is also discussed in this paper.

Pradhan, Jedidiah; Das, Nisith K.; Chakrabarti, Alok

2014-09-01

228

Multistation refrigeration system  

NASA Technical Reports Server (NTRS)

A closed cycle refrigeration (CCR) system is disclosed for providing cooling at different parts of a maser. The CCR includes a first station for cooling the maser's parts, except the amplifier portion, to 4.5 K. The CCR further includes means with a 3.0 K station for cooling the maser's amplifier to 3.0 K and, thereby, increases the maser's gain and/or bandwith by a significant factor. The means which provide the 3.0 K cooling include a pressure regulator, heat exchangers, an expansion valve, and a vacuum pump, which coact to cause helium, provided from a compressor, to liquefy and thereafter expand so as to vaporize. The heat of vaporization for the helium is provided by the maser amplifier, which is thereby cooled to 3.0 K.

Wiebe, E. R. (inventor)

1978-01-01

229

Cryogenic refrigeration apparatus  

DOEpatents

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.

Crunkleton, James A. (Cambridge, MA)

1992-01-01

230

Cryogenic refrigeration apparatus  

DOEpatents

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. 6 figs.

Crunkleton, J.A.

1992-03-31

231

A comparison between Anderko's model with composition-dependent physical interaction parameters and SRK-based hexamer model for HFC and HF systems  

Microsoft Academic Search

A new composition-dependent mixing rule in physical contribution term of AEOS by Anderko [A. Anderko, Phase equilibria in aqueous systems from an equation of state based on the chemical approach. Fluid Phase Equilibria, 1991, 65, 89.] was introduced to predict the phase behavior for HFC-134a+HF and HFC-32+HF binary systems. The approach developed in this work gives better results for systems

Jungho Cho; Seungbaik Rho; Sangjin Park; Jongcheon Lee; Hwayong Kim

1998-01-01

232

Adsorbability of 1,1,1,2-tetrafluoromethane (HFC134a) onto plasma-treated activated carbon in CF{sub 4} and CCl{sub 4}  

SciTech Connect

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 included into the pores having radii greater than 7.5 {angstrom} and with less than 7.5 {angstrom} 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.

Tanada, Seiki; Kawasaki, Naohito; Nakamura, Takeo; Ohue, Takashi [Kinki Univ., Higashi, Osaka (Japan). Faculty of Pharmaceutical Sciences] [Kinki Univ., Higashi, Osaka (Japan). Faculty of Pharmaceutical Sciences; Abe, Ikuo [Osaka Municipal Technical Research Inst., Osaka (Japan)] [Osaka Municipal Technical Research Inst., Osaka (Japan)

1997-07-15

233

Magnetic refrigeration for maser amplifier cooling  

NASA Technical Reports Server (NTRS)

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

Johnson, D. L.

1982-01-01

234

Mixture Experiments  

SciTech Connect

A mixture experiment involves combining two or more components in various proportions or amounts and then measuring one or more responses for the resulting end products. Other factors that affect the response(s), such as process variables and/or the total amount of the mixture, may also be studied in the experiment. A mixture experiment design specifies the combinations of mixture components and other experimental factors (if any) to be studied and the response variable(s) to be measured. Mixture experiment data analyses are then used to achieve the desired goals, which may include (i) understanding the effects of components and other factors on the response(s), (ii) identifying components and other factors with significant and nonsignificant effects on the response(s), (iii) developing models for predicting the response(s) as functions of the mixture components and any other factors, and (iv) developing end-products with desired values and uncertainties of the response(s). Given a mixture experiment problem, a practitioner must consider the possible approaches for designing the experiment and analyzing the data, and then select the approach best suited to the problem. Eight possible approaches include 1) component proportions, 2) mathematically independent variables, 3) slack variable, 4) mixture amount, 5) component amounts, 6) mixture process variable, 7) mixture of mixtures, and 8) multi-factor mixture. The article provides an overview of the mixture experiment designs, models, and data analyses for these approaches.

Piepel, Gregory F.

2007-12-01

235

Solid-Vapor Sorption Refrigeration Systems  

E-print Network

SOLID-VAPOR SORPTION REFRIGERATION SYSTEMS DR. WILLIAM GRAEBEL DR. UWE ROCKENFELLER MR. LANCE KIROL Engineer President Chief Engineer Rocky Research Rocky Research Rocky Research Boulder city, NV Boulder city, NV Boulder City, NV Abstract... Complex compound sorption reactions are ideally suited for use in refrigeration cycles as an economically viable alternative to CFC refrigerants. Complex compound refrigeration provides a number of energy-saving advantages over present refrigeration...

Graebel, W.; Rockenfeller, U.; Kirol, L.

236

Magnetic refrigeration apparatus and method  

DOEpatents

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.

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

1984-01-01

237

Magnetic refrigeration apparatus and method  

SciTech Connect

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.

Barclay, J.A.; Overton, W.C.; Stewart, W.F. Jr.

1984-07-17

238

10 CFR 429.42 - Commercial refrigerators, freezers, and refrigerator-freezers.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Commercial refrigerators, freezers, and refrigerator-freezers...ENFORCEMENT FOR CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.42 Commercial refrigerators, freezers, and...

2013-01-01

239

10 CFR 429.42 - Commercial refrigerators, freezers, and refrigerator-freezers.  

...2014-01-01 2014-01-01 false Commercial refrigerators, freezers, and refrigerator-freezers...ENFORCEMENT FOR CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.42 Commercial refrigerators, freezers, and...

2014-01-01

240

10 CFR 429.42 - Commercial refrigerators, freezers, and refrigerator-freezers.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Commercial refrigerators, freezers, and refrigerator-freezers...ENFORCEMENT FOR CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.42 Commercial refrigerators, freezers, and...

2012-01-01

241

A generalized magnetic refrigeration scheme  

NASA Astrophysics Data System (ADS)

We have investigated the magnetocaloric effects in antiferromagnets and compared them with those in ferromagnets using Monte Carlo simulations. In antiferromagnets, the magnetic entropy reaches a maximum value at a finite magnetic field when the temperature is fixed below the Néel temperature. Using the fact, we proposed a protocol for applying magnetic fields to achieve the maximum efficiency for magnetic refrigeration in antiferromagnets. In particular, we found that at low temperatures, antiferromagnets are more useful for magnetic refrigeration than ferromagnets.

Tamura, Ryo; Ohno, Takahisa; Kitazawa, Hideaki

2014-02-01

242

Electronic band structures and x-ray photoelectron spectra of ZrC, HfC, and TaC  

Microsoft Academic Search

The band structures and densities of states (DOSs) of ZrC, HfC, and TaC were calculated by the augmented-plane-wave method, and the x-ray photoelectron spectra of valence bands of these compounds were observed. The theoretical energy distribution curves (EDCs) were in good agreement with the experimental EDCs. These band structures resemble each other and also those of TiC obtained by our

Hideo Ihara; Masayuki Hirabayashi; Hiroshi Nakagawa

1976-01-01

243

Adsorption of atomic oxygen on HfC and TaC (1 1 0) surface from first principles  

NASA Astrophysics Data System (ADS)

We investigated the initial adsorption of oxygen atom on the HfC (1 1 0) and TaC (1 1 0) surface using first principles. Both the carbides have the same crystal structure, a sodium-chloride structure. The (1 1 0) surfaces of the carbides were modeled with (2 × 1) supercells. Every supercell is composed of five atomic planes. Our results demonstrate that the preferred site for oxygen atom is the C-Hf bridge site and the Ta-Ta bridge site on the HfC (1 1 0) and TaC (1 1 0) surface, respectively. The adsorption sites are different from the one on the (1 0 0) surfaces of the carbides. For the carbides, the adsorption energies of oxygen on the (1 1 0) surfaces are larger than that on the (1 0 0) surfaces. There exists the Csbnd O bond in O/HfC (1 1 0), while no Csbnd O bond is found in O/TaC (1 1 0), indicating that the adsorption mechanism of atomic oxygen on the TaC (1 1 0) surface is different from that on the HfC (1 1 0) surface at initial adsorption stage.

Liu, Dongliang; Deng, Jianguo; Jin, Yongzhong; He, Cheng

2012-11-01

244

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

line is subcooled liquid. The region enclosed by the pair represents a mixture of liquid and vapor are as follows: Assume the system is charged with a mixture having a concentration of component A designated, the refrigerant will be a mixture of liquid and vapor, as usually occurs in a single-refrigerant system. One

Oak Ridge National Laboratory

245

Initial parametric results using CYCLEZ: A LMTD-specified, Lorenz-Meutzner cycle refrigerator-freezer model  

NASA Astrophysics Data System (ADS)

A computer model representing a two-evaporator, two-intercooler refrigerator-freezer operating at steady-state with nonazeotropic refrigerant mixtures (CYCLEZ) has been developed at Oak Ridge National Laboratory (ORNL). This model is being used to assess the effects of system design and operating parameters on the cycle performance of a refrigerator-freezer designed around the Lorenz-Meutzner (L-M) circuit. Separate evaporators for the freezer and fresh-food compartments are modeled, as well as two intercoolers that subcool liquid refrigerant from the condenser by heat transfer with low-pressure refrigerant. The CYCLEZ refrigerator/freezer model is derived from the CYCLEZ heat-pump model developed originally by the National Institute of Standards and Technology (NIST). CYCLEZ currently uses the Carnahan-Starling-DeSantis (CSD) equation-of-state to compute refrigerant thermodynamic properties, so that new refrigerants can easily be added. Condenser and evaporator heat-exchanger performance are defined by user-specified overall LMTDs which allow equivalent heat-exchanger sizing per unit refrigeration load to be maintained for different refrigerant mixtures. A more consistent formulation of overall heat-exchanger LMTD is applied across the condenser superheated and two-phase regions as well as over the two evaporators. Source and sink conditions are specified in terms of inlet and outlet temperatures of the external fluid streams. Intercooler high-side (subcooling) delta Ts and relative fresh-food-to-freezer load ratio are also user-specified. These features make this model well suited for evaluating the optimal thermodynamic cycle requirements of the five heat exchangers used in the L-M refrigerator/freezer circuit.

Rice, C. Keith; Sand, James R.

246

Auto defrost refrigerator  

SciTech Connect

A refrigerator is described including: an upper freezer compartment, a lower fresh food compartment and an insulating partition separating the compartments; an evaporator chamber separate from the freezer and fresh food compartment and above the fresh food compartment; means for conducting relatively cold air from the chamber to the freezer compartment and means for conducting relatively cold air from the chamber to the fresh food compartment; return means for returning relatively warm air from the freezer compartment to the chamber; duct means connecting the lower portion of the fresh food compartment with the chamber for returning relative warm air from the fresh food compartment to the chamber; evaporator means, including a first evaporator section positioned in the evaporator chamber and a second evaporator section positioned in the duct means, for cooling air passing thereover; and fan means for withdrawing relatively warm air from the compartments, circulating the air from the freezer compartment over the first evaporator section, circulating the air from the fresh food compartment serially over both the second and first evaporator sections and discharging cooled air from the evaporator chamber.

Schulze, J.L.

1988-05-03

247

Expendable refrigeration control  

SciTech Connect

This patent describes, in a refrigeration system, an apparatus for controlling the opening and closing operation of a liquid flow valve for dispensing fluid fed thereto from a reservoir and using the inherent gas pressure from the reservoir, comprising in combination: (a) a pneumatic piston operated actuator device having a piston side and a rod side, the rod side being operable connected to the flow valve for opening and closing the same; and (b) control means for controlling the operation of the pneumatic actuator device. The control means has a first pneumatic linear timer valve having a cycle time delay and is connected to a gas pressure line of the reservoir. A second pneumatic linear timer valve has an injection time delay and also connected to the gas pressure line of the reservoir, the first and second pneumatic linear timer valves being interconnected through a control valve. A pneumatic actuator control valve is connected to the gas pressure line of the reservoir and to the piston side and rod side of the actuator device for controlling the operation of the actuator device. The first pneumatic linear timer valve is connected to the actuator control valve to operate same after the cycle time delay to cause the actuator device to operate the liquid flow valve to dispense fluid from the reservoir and to further actuate the second pneumatic linear device to initiate the injection time delay and open condition of the liquid flow valve.

Clarke, K.J.; Lamb, G.

1986-12-23

248

Performance Analysis of the Absorption Refrigeration Cycle using TFE/NMP as a Working Fluid  

NASA Astrophysics Data System (ADS)

Performance analysis was made for the absorption refrigeration cycle using TFE/NMP as a working fluid. In the calculation the steady states model, and the separation and mixture of refrigerant model were constructed. The experimental equipment of the absorption refrigeration cycle was also manufactured. The calculation model and the experimental equipment consisted of the generator, the condenser, the evaporator, the absorber, the partial condenser, the rectifier, the reservoir, the heat recovery heat exchanger, the solution pump and the expansion valve. The reservoir was used to store the liquid refrigerant for changing the solution concentration in the cycle. The calculation and experimental results showed the agreement at the lower generation temperature, but presented the opposite trend because of the influence of the heat release in the partial condenser. The calculation and experimental results showed the good agreement for the separation and mixture of refrigerant process. In results, it was found that this absorption refrigeration cycle using TFE/NMP as a working fluid had possibility to utilize recovering the wide range waste heat to energy.

Kato, Masashi; Tsujimori, Atsushi; Morita, Hajime

249

46 CFR 151.40-11 - Refrigeration systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Refrigeration systems. 151.40-11 Section...Control Installations § 151.40-11 Refrigeration systems. (a) Boiloff systems... (b) Vapor compression, tank refrigeration, and secondary refrigeration...

2010-10-01

250

Separating Mixtures  

NSDL National Science Digital Library

Students learn how to classify materials as mixtures, elements or compounds and identify the properties of each type. The concept of separation of mixtures is also introduced since nearly every element or compound is found naturally in an impure state such as a mixture of two or more substances, and it is common that chemical engineers use separation techniques to separate mixtures into their individual components. For example, the separation of crude oil into purified hydrocarbons such as natural gas, gasoline, diesel, jet fuel and/or lubricants.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

251

Superinsulation in refrigerators and freezers  

SciTech Connect

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.

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

1998-02-01

252

Shear viscosity of binary mixtures: The Gay-Berne potential  

NASA Astrophysics Data System (ADS)

The Gay-Berne (GB) potential model is an interesting and useful model to study the real systems. Using the potential model, we intend to examine the thermodynamical properties of some anisotropic binary mixtures in two different phases, liquid and gas. For this purpose, we apply the integral equation method and solve numerically the Percus-Yevick (PY) integral equation. Then, we obtain the expansion coefficients of correlation functions to calculate the thermodynamical properties. Finally, we compare our results with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, benzene + methanol, cyclohexane + ethanol, benzene + ethanol, carbon tetrachloride + ethyl acetate, and methanol + ethanol]. The results show that the GB potential model is capable for predicting the thermodynamical properties of binary mixtures with acceptable accuracy.

Khordad, R.

2012-05-01

253

A class of internally irreversible refrigeration cycles  

NASA Astrophysics Data System (ADS)

A Carnot-like irreversible refrigeration cycle is modelled with two isothermal and two non-adiabatic, irreversible processes. The generic source of internal irreversibility, measured by the Clausius inequality, is a general irreversibility term which could include any heat leaks into the Joule - Thompson expansion valve, the evaporator and compressor cold boxes. This cycle is optimized first for maximum refrigeration power and maximum refrigeration load, then for maximum coefficient of performance. Its performances are compared with those of the endoreversible refrigeration cycle, based on a propane stage of a classical cascade liquefaction cycle example. Both cycle models achieve optimum power and maximum refrigeration load at nearly the same refrigeration temperature, but only the coefficient of performance of the irreversible refrigeration cycle reaches a maximum. Moreover, its prediction of heat conductance allocation between evaporator and condenser appears to be not only more conservative, but also more realistic for actual design considerations of refrigeration cycles.

Ait-Ali, Mohand A.

1996-03-01

254

Refrigerator Thermometers: Cold Facts about Food Safety  

MedlinePLUS

... foods, it's important to get foods that need refrigeration into your fridge quickly. Leaving perishable foods out ... meat, poultry, seafood, eggs, or produce that requires refrigeration to sit at room temperature for more than ...

255

A review of pulse tube refrigeration  

NASA Technical Reports Server (NTRS)

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.

Radebaugh, Ray

1990-01-01

256

REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS  

EPA Science Inventory

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

257

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...

258

Krypton based adsorption type cryogenic refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

259

Thermoelectric refrigerator having improved temperature stabilization means  

DOEpatents

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.

Falco, Charles M. (Woodridge, IL)

1982-01-01

260

Cascade Joule-Thomson refrigerators  

NASA Astrophysics Data System (ADS)

The design criteria for cascade Joule-Thomson refrigerators for cooling in the temperature range from 300 K to 4.2 K were studied. The systems considered use three or four refrigeration stages with various working gases to achieve the low temperatures. Each stage results in cooling to a progressively lower temperature and provides cooling at intermediate temperatures to remove the substantial amount of parasitic heat load encountered in a typical dewar. With careful dewar design considerable cooling can be achieved with moderate gas flows. For many applications, e.g., in the cooling of sensitive sensors, the fact that the refrigerator contains no moving parts and may be remotely located from the gas source is of considerable advantage. A small compressor suitable for providing the gas flows required was constructed.

Tward, E.; Steyert, W. A.

1983-12-01

261

Self-regulated energy saving refrigeration circuit  

SciTech Connect

A self-regulated refrigeration circuit incorporating a compressor/condenser guard device for cooling compressor refrigerant output prior to application to a condenser and for reevaporating liquid refrigerant discharged from the evaporators prior to its return to the compressor. A pressure differential chamber and high velocity suction line operate in conjunction with the compressor/condenser guard device to control refrigerant flow through the evaporators in both the freeze and defrost cycles of the circuit.

Aleksandrow, J.

1985-07-23

262

Refrigerator temperature and defrost control  

SciTech Connect

This patent describes a refrigerator having cooling means including an evaporator and a compressor for cooling a refrigerated compartment. The compressor has first and second power terminals and defrost means for heating the evaporator to remove frost. The defrost means has first and second power terminals, and a source of power coupled to first and second power conductors, an electrical control for controlling the application of power to the power terminals of each of the compressor and the defrost means. The control comprises: defrost initiation means for producing a defrost initiation signal upon a determination that the energization of the defrost means is desired.

Janke, D.E.

1987-05-12

263

Pot-in-Pot Refrigeration  

NSDL National Science Digital Library

In this activity (on page 2 of PDF), learners create a low-tech refrigerator that requires no electricity to keep food from spoiling. It uses only clay pots, one smaller than the other and separated by wet sand. As the water evaporates from the sand, it lowers the temperature inside the inner pot, similar to how evaporation from a sweaty person lowers the person's body temperature. This "refrigerator" with no moving parts is great for exploring evaporative cooling, as well as scientific innovation, especially since it has been used successfully in Africa.

Omsi

2004-01-01

264

Wheel-type magnetic refrigerator  

DOEpatents

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.

Barclay, J.A.

1983-10-11

265

Wheel-type magnetic refrigerator  

DOEpatents

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.

Barclay, J.A.

1982-01-20

266

Wheel-type magnetic refrigerator  

DOEpatents

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.

Barclay, John A. (Los Alamos, NM)

1983-01-01

267

Solar Refrigerators Store Life-Saving Vaccines  

NASA Technical Reports Server (NTRS)

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

2014-01-01

268

Ternary Dy-Er-Al magnetic refrigerants  

DOEpatents

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.

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

1995-07-25

269

21 CFR 1250.34 - Refrigeration equipment.  

Code of Federal Regulations, 2010 CFR

...and Drugs 8 2010-04-01 2010-04-01 false Refrigeration equipment. 1250.34 Section 1250.34 Food and Drugs...on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment. Each refrigerator shall be equipped with...

2010-04-01

270

Method and apparatus for desuperheating refrigerant  

DOEpatents

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

Zess, James A. (Kelso, WA); Drost, M. Kevin (Richland, WA); Call, Charles J. (Richland, WA)

1997-01-01

271

Piston sealing arrangement for a cryogenic refrigerator  

SciTech Connect

A sealing arrangement for a rectilinear reciprocable piston within a cryogenic refrigerator comprising a buffer defined by dual O-rings disposed around the circumference of the piston and containing pressurized gas of the same type as the refrigeration gas. The buffer limits or prevents both the entrance of contaminants and also the escape of the refrigeration gas.

Green, G.F.; Humphrey, J.C.

1984-02-21

272

Ternary Dy-Er-Al magnetic refrigerants  

DOEpatents

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

Gschneidner, Jr., Karl A. (Ames, IA); Takeya, Hiroyuki (Ibaraki, JP)

1995-07-25

273

Compact heat exchanger for refrigeration systems  

Microsoft Academic Search

In combination with a vapor\\/compression refrigeration system, a defrosting apparatus for receiving mixed phase refrigerant emanating from the system evaporator outlet during system defrost, and transmitting only superheated gaseous refrigerant to the system compressor inlet, is described comprising: a cylindrical metal body having a preselected length, diameter and wall thickness, and top and bottom ends; a metal defrost tube means

1988-01-01

274

Magnetocaloric refrigeration near room temperature (invited)  

Microsoft Academic Search

Modern society relies on readily available refrigeration. The ideal cooling machine would be a compact, solid state, silent and energy-efficient heat pump that does not require maintenance. Magnetic refrigeration has three prominent advantages compared to compressor-based refrigeration. First, there are no harmful gases involved, second it may be built more compact as the working material is a solid and third

E. Brück; O. Tegus; D. T. C. Thanh; K. H. J. Buschow

2007-01-01

275

Theoretical and experimental investigation of an ammonia–water power and refrigeration thermodynamic cycle  

Microsoft Academic Search

A combined thermal power and cooling cycle proposed by Goswami is under intensive investigation, both theoretically and experimentally. The proposed cycle combines the Rankine and absorption refrigeration cycles, using a binary ammonia–water mixture as the working fluid. This cycle can be used as a bottoming cycle using waste heat from a conventional power cycle or an independent cycle using low

G Tamm; D. Y Goswami; S Lu; A. A Hasan

2004-01-01

276

Airborne trifluoroacetic acid and its fraction from the degradation of HFC-134a in Beijing, China.  

PubMed

Trifluoroacetic acid (TFA) has been attracting increasing attention worldwide because of its increased environmental concentrations and high aquatic toxicity. Atmospheric deposition is the major source of aquatic TFA, but only a few studies have reported either air concentrations or deposition fluxes for TFA. This is the first study to report the atmospheric concentrations of TFA in China, where an annular denuder and filter pack collection system were deployed at a highly urbanized site in Beijing. In total, 144 air samples were collected over the course of 1 year (from May 2012 to April 2013) and analyzed directly using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) or following derivatization by gas chromatography-mass spectrometry (GC-MS). The annual mean atmospheric concentration of TFA was 1580 ± 558 pg/m(3), higher than the previously reported annual mean levels in Germany and Canada. For the first time, it was demonstrated that maximum concentrations of TFA were frequently observed in the afternoon, following a diurnal cycle and suggesting that a major source of airborne TFA is likely degradation of volatile precursors. Using a deposition model, the annual TFA deposition flux was estimated to be 619 ± 264 ?g m(-2) year(-1). Nevertheless, a box model estimated that the TFA deposition flux from the degradation of HFC-134a contributed only 14% (6-33%) to the total TFA deposition flux in Beijing. Source analysis is quite important for future TFA risk predictions; therefore, future research should focus on identifying additional sources. PMID:24628386

Wu, Jing; Martin, Jonathan W; Zhai, Zihan; Lu, Keding; Li, Li; Fang, Xuekun; Jin, Hangbiao; Hu, Jianxin; Zhang, Jianbo

2014-04-01

277

Multilayer thermionic refrigerator and generator  

Microsoft Academic Search

A new method of refrigeration is proposed. Cooling is obtained by thermionic emission of electrons over periodic barriers in a multilayer geometry. These could be either Schottky barriers between metals and semiconductors or else barriers in a semiconductor superlattice. The same device is an efficient power generator. A complete theory is provided.

G. D. Mahan; J. O. Sofo; M. Bartkowiak

1998-01-01

278

Low-temperature magnetic refrigerator  

DOEpatents

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.

Barclay, John A. (Los Alamos, NM)

1985-01-01

279

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

280

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

281

Low-temperature magnetic refrigerator  

SciTech Connect

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.

Barclay, J. A.

1985-04-02

282

Solar-powered jet refrigerator  

NASA Technical Reports Server (NTRS)

Design criteria are easily evaluated by tool. Thermodynamic analysis of solar-powered vapor-jet refrigerator combines important performance parameters in nomogram that assist design of practical system. Projected coefficients of performance for difference ejector configurations, working fluids, and other design variables are easily obtained from nomogram.

Chai, V. W.; Lansing, F. L.

1979-01-01

283

Model Based Control Refrigeration Systems  

E-print Network

Model Based Control of Refrigeration Systems Ph.D. Thesis Lars Finn Sloth Larsen Central R & D The work presented in thesis has been carried out under the Industrial Ph.D. programme supported, Danfoss A/S and at the Department of Control Engineering, Institute of Electronic Systems, Aal- borg

284

Magnetic refrigeration using flux compression in superconductors  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

285

The high-capacity, spaceborne, Vuilleumier refrigerator  

NASA Astrophysics Data System (ADS)

This paper describes the features and gives the thermal performance capabilities of the high-capacity (Hi Cap), Vuilleumier cryogenic refrigerator. This refrigerator simultaneously cools at three different temperature levels, the lowest being below 15 K. It is designed to cool electro-optical sensors in a spaceborne environment. The basic design of the Hi Cap refrigerator is discussed, and the individual machine elements are identified. Data on the thermal performance of this refrigerator is presented for various thermal load conditions on the three cold stages. The capability of this refrigerator for off-design-speed operation is also discussed.

Doody, R. D.

1980-01-01

286

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

Code of Federal Regulations, 2012 CFR

...Failure Mode and Effects Analysis in Design (Design FMEA...Failure Mode and Effects Analysis in Manufacturing and Assembly...Failure Mode and Effects Analysis for Machinery (Machinery FMEA) shall be applied to the design and...

2012-07-01

287

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

...Failure Mode and Effects Analysis in Design (Design FMEA...Failure Mode and Effects Analysis in Manufacturing and Assembly...Failure Mode and Effects Analysis for Machinery (Machinery FMEA) shall be applied to the design and...

2013-07-01

288

Keeping Cool With Solar-Powered Refrigeration  

NASA Technical Reports Server (NTRS)

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

2003-01-01

289

Magnetic Refrigeration: Perfecting the Process  

NSDL National Science Digital Library

Currently, conventional refrigeration technology cyclically pressurizes and depressurizes Chlorofluorocarbons (commonly known as Freon) to provide cooling in modern air conditioners and kitchen refrigerators. One of the main problems with this process is the unavoidable leakage of Freon into the atmosphere, causing ozone depletion and pollution. Additionally, current refrigeration cannot easily reach temperatures below 30 K (-405° F), which are necessary for satellite sensor cooling and hydrogen liquification (for the future fleet of hydrogen-powered cars) without multi-stage cooling that can be grossly inefficient. An exciting and revolutionary alternative to the presently inefficient and environmentally harmful conventional refrigeration is magnetic refrigeration. This technology is based on the magnetocaloric effect of a material (the temperature change of that material due to the alignment of its magnetic spins when subjected to a magnetic field). Prototype magnetic refrigerators use metal alloys and permanent magnets to exploit this effect. A metal alloy is cyclically magnetized and demagnetized to provide powerful and efficient cooling without damage to the earthâs atmosphere. The alloy is placed in the cooling chamber and a strong magnetic field is applied to magnetize the substance, thereby increasing its temperature but cooling the surrounding air in the refrigeration compartment. Then the material is removed from both the cooling chamber and the magnetic field. This allows the atomic spins to return to a disordered state and the stored heat to be released, preparing the material for another cycle of cooling. Magnetic refrigeration is both nondestructive and theoretically more efficient than either vapor expansion or radiant cooling. In order to optimize the cooling effects of a magnetic refrigerator, a metal alloy must be found that exhibits optimal magnetocaloric effects at temperature ranges of interest. A recent publication in Nature (âHysteresis losses in Gd5Ge2Si2 by addition of ironâ, Nature, Volume 429, 24 June 2004, pages 853-857) shows that certain compounds, doped with iron, possess greatly enhanced effects. This project was focused on examining Holmium-Titanium-Germanium (HoTiGe) alloys doped with iron under the prediction they would also possess similar enhancements. Improved cooling potential around 90 K (-298° F) was previously documented by a group of Dutch scientists (âMagnetic-phase transitions and magnetocaloric effectsâ, Physica B, Volume 319, 15 February 2002, pages 174-192). This summer, we revisited the Dutch research and found large magnetocaloric effects on this particular system at 15 K (-433° F) and 2 K (-456° F) as well. Further, we have identified the specific phase of the alloy that is responsible for these low-temperature magnetocaloric effects, Ho58Ti5Ge36Fe. These results could have a major impact on low-temperature cooling techniques in the future by greatly improving the efficiency of magnetic cooling at low temperatures.

Baumgold, Ben

2005-01-01

290

Dilution Refrigerator for Nuclear Refrigeration and Cryogenic Thermometry Studies  

NASA Astrophysics Data System (ADS)

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

Nakagawa, Hisashi; Hata, Tohru

2014-07-01

291

Practical concerns for refrigerant management in buildings  

SciTech Connect

The new laws that regulate the HVAC industry are sometimes confusing and carry heavy fines for non-compliance. The guidelines set forth in ASHRAE Standard 15-1992, Safety Code for Mechanical Refrigeration, may not show up in local codes for quite some time, which leaves the question of diligence in the hands of the building owner. In the case of equipment retrofit, city permits may not be acquired and whether Standard 15 is being met by contractors and owners is a matter of choice. Standard 15 involves refrigeration room ventilation, doors and passageways, long and short-term refrigerant monitoring, pressure-relief piping, alarms, self-contained breathing apparatus requirements, etc. In terms of being practical with liability, nothing short of strict compliance with Standard 15 will provide protection. Once beyond chiller room safety, EPA compliance, namely Rule 608 (National Emissions Reduction Program) of Title VI Clean Air Act of 1990, requires minimal record keeping when CFC and HCFC refrigerants are present. The EPA suggests the following measures as a means of getting started with a practical approach to managing refrigerant in buildings: (1) designate a facility refrigerant manager; (2) conduct an inventory of equipment and refrigerants; and (3) develop a refrigerant management plan. The plan should combine these actions: maintaining existing equipment; retrofitting equipment to alternative refrigerants; and replacing oil or inefficient equipment. Lastly, when making decisions about replacement refrigerants, keep in mind that the United States could be moving toward mandated limits on greenhouse gas emissions.

Wylie, D. (ASW Engineering, Tustin, CA (United States))

1994-01-01

292

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

NASA Astrophysics Data System (ADS)

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

Komatsubara, Takeo; Sunaga, Takasi; Takahasi, Yasuki

293

A compact rotating dilution refrigerator.  

PubMed

We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid (4)He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10(-3) rad s(-1) up to angular velocities in excess of 2.5 rad s(-1). The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated. PMID:24182127

Fear, M J; Walmsley, P M; Chorlton, D A; Zmeev, D E; Gillott, S J; Sellers, M C; Richardson, P P; Agrawal, H; Batey, G; Golov, A I

2013-10-01

294

A compact rotating dilution refrigerator  

NASA Astrophysics Data System (ADS)

We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10-3 rad s-1 up to angular velocities in excess of 2.5 rad s-1. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

Fear, M. J.; Walmsley, P. M.; Chorlton, D. A.; Zmeev, D. E.; Gillott, S. J.; Sellers, M. C.; Richardson, P. P.; Agrawal, H.; Batey, G.; Golov, A. I.

2013-10-01

295

Suction muffler for refrigeration compressor  

DOEpatents

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. 5 figs.

Nelson, R.T.; Middleton, M.G.

1983-01-25

296

Suction muffler for refrigeration compressor  

DOEpatents

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.

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

1983-01-01

297

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

ERIC Educational Resources Information Center

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

Carey, John

298

Environmental Fate of the Next Generation Refrigerant 2,3,3,3-Tetrafluoropropene (HFO-1234yf).  

PubMed

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 (GRSO4), magnetite (Fe3O4), 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

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

2014-11-18

299

Magnetic refrigerator for hydrogen liquefaction  

NASA Astrophysics Data System (ADS)

This paper reviews the status of magnetic refrigeration system for hydrogen liquefaction. There is no doubt that hydrogen is one of most important energy sources in the near future. In particular, liquid hydrogen can be utilized for infrastructure construction consisting of storage and transportation. When we compare the consuming energy of hydrogen liquefaction with high pressurized hydrogen gas, FOM must be larger than 0.57 for hydrogen liquefaction. Thus, we need to develop a highly efficient liquefaction method. Magnetic refrigeration using the magneto-caloric effect has potential to realize not only the higher liquefaction efficiency >50%, but also to be environmentally friendly and cost effective. Our hydrogen magnetic refrigeration system consists of Carnot cycle for liquefaction stage and AMR (active magnetic regenerator) cycle for precooling stages. For the Carnot cycle, we develop the high efficient system with >80% liquefaction efficiency by using the heat pipe. For the AMR cycle, we studied two kinds of displacer systems, which transferred the working fluid. We confirmed the AMR effect with the cooling temperature span of 12 K for 1.8 T of the magnetic field and 6 s of the cycle. By using the simulation, we estimate the efficiency of the hydrogen liquefaction plant for 10 kg/day. A FOM of 0.47 is obtained for operation temperature between 20 K and 77 K including LN2 work input.

Numazawa, T.; Kamiya, K.; Utaki, T.; Matsumoto, K.

2014-07-01

300

A novel refrigerator attaining temperature below ? point  

NASA Astrophysics Data System (ADS)

The present study proposes a novel refrigerator in theory, which uses 4He as working fluid to directly reach 2.3 K and uses a small amount of 3He to attain the temperature below 1.7 K. The compact and highly efficient new refrigerator works with the Vuilleumier cycle. The novel refrigerator is driven by a thermal compressor which creatively uses mix-refrigerants J-T refrigerator alternative to liquid nitrogen as the power source. Furthermore, the Vuilleumier cycle can be used to achieve temperature below liquid helium with the improvement of the ultra-low temperature regenerator material. A new method of reaching the temperature below 1.7 K is proposed on the regenerative refrigerator, which could be an important breakthrough for the cryogenic science and technology.

Zhou, Yuan; Xue, XiaoDai; Wang, JunJie; Gu, Chao

2012-08-01

301

Magnetocaloric refrigeration near room temperature (invited)  

NASA Astrophysics Data System (ADS)

Modern society relies on readily available refrigeration. The ideal cooling machine would be a compact, solid state, silent and energy-efficient heat pump that does not require maintenance. Magnetic refrigeration has three prominent advantages compared to compressor-based refrigeration. First, there are no harmful gases involved, second it may be built more compact as the working material is a solid and third magnetic refrigerators generate much less noise. Recently, a new class of magnetic refrigerant materials for room-temperature applications was discovered. These new materials have important advantages over existing magnetic coolants: They exhibit a large magnetocaloric effect (MCE) in conjunction with a magnetic phase transition of first order. This MCE is, larger than that of Gd metal, which is used in the demonstration refrigerators built to explore the potential of this evolving technology. In the present review, we compare the different materials considering both scientific aspects and industrial applicability.

Brück, E.; Tegus, O.; Thanh, D. T. C.; Buschow, K. H. J.

2007-03-01

302

TOPICAL REVIEW: Developments in magnetocaloric refrigeration  

NASA Astrophysics Data System (ADS)

Modern society relies on readily available refrigeration. Magnetic refrigeration has three prominent advantages compared with compressor-based refrigeration. First, there are no harmful gases involved; second, it may be built more compactly as the working material is a solid; and third, magnetic refrigerators generate much less noise. Recently a new class of magnetic refrigerant-materials for room-temperature applications was discovered. These new materials have important advantages over existing magnetic coolants: they exhibit a large magnetocaloric effect (MCE) in conjunction with a magnetic phase-transition of first order. This MCE is larger than that of Gd metal, which is used in the demonstration refrigerators built to explore the potential of this evolving technology. In the present review we compare the different materials considering both scientific aspects and industrial applicability. Because fundamental aspects of MCE are not so widely discussed, we also give some theoretical considerations.

Brück, Ekkes

2005-12-01

303

Performance and Safety of LPG Refrigerants  

Microsoft Academic Search

Ozone depletion and global warming require replacement of chlorouo- rocarbon refrigerants like R12. The hydrouorocarbon R134a is nonammable, difcult to synthesize, has zero ozone depletion and high global warming. LPG refrigerants are highly ammable, occur naturally, have zero ozone de- pletion and negligible global warming. In Germany, most new refrigerators use R600a and many heat pumps and air conditioners now

I. L. Maclaine-cross; E. Leonardi

304

Modeling phase equilibria in mixtures containing hydrogen fluoride and halocarbons  

SciTech Connect

Recently, much attention has been focused on the production of environmentally acceptable refrigerants, which not only offer desirable physico-chemical properties, but do not deplete the ozone layer and do not cause the greenhouse effect. The production of such refrigerants involves the separation of multicomponent mixtures containing hydrogen fluoride, hydrogen chloride, and various chlorinated and fluorinated hydrocarbons. Therefore, it is indispensable to know the phase behavior of these mixtures. While the phase behavior of refrigerant mixtures can be adequately modeled in the absence of HF using standard thermodynamic techniques, drastically increases the complexity of the mixture because of its unusually strong association. The association of HF manifests itself in its significantly reduced gas-phase compressibility factor and the strong nonideality of mixtures containing HF and hydrocarbons or halocarbons. In this work, the authors develop an accurate, yet simple, association model for HF and compare it with simulation data. The model is combined with a simple equation of state to yield a closed-form expression that is applicable to both pure fluids and mixtures. In addition to representing the pure-component data for HF, the theory accurately predicts phase equilibria in HF + halocarbon systems.

Lencka, M. (Polish Academy of Sciences, Warszawa (Poland)); Anderko, A. (Lawrence Berkeley Lab., CA (United States) Polish Academy of Sciences, Warszawa (Poland))

1993-03-01

305

Compact heat exchanger for refrigeration systems  

SciTech Connect

In combination with a vapor/compression refrigeration system, a defrosting apparatus for receiving mixed phase refrigerant emanating from the system evaporator outlet during system defrost, and transmitting only superheated gaseous refrigerant to the system compressor inlet, is described comprising: a cylindrical metal body having a preselected length, diameter and wall thickness, and top and bottom ends; a metal defrost tube means having a first tube end; a first metal end cap, fixedly attached to the bottom end of the body, for sealably enclosing the bottom end; a second metal end cap, fixedly attached to the top end of the body, for sealably enclosing the top end thereby forming, in cooperation with the first cap, a chamber therewithin; a first metal standpipe tube, passing through and fixedly attached to the second end cap, and extending a first preselected depth into the chamber, for receiving the mixed phase refrigerant from the evaporator outlet and transmitting the mixed phase refrigeration into the chamber, the mixed phase refrigerant absorbing the heat transmitted therein from the coil and transforming the mixed phase refrigerant into superheated low pressure refrigerant gas; and a second metal standpipe tube, passing through and fixedly attached to the second end cap, and extending a second preselected depth into the chamber, the first depth of the first standpipe being substantially greater than the second depth, for receiving and transmitting only the superheated refrigerant to the compressor inlet.

Warren, J.

1988-01-12

306

16 CFR Appendix A2 to Part 305 - Refrigerators and Refrigerators-Freezers With Manual Defrost  

Code of Federal Regulations, 2010 CFR

...Refrigerators-Freezers With Manual Defrost A2 Appendix A2 to Part 305 Commercial Practices FEDERAL TRADE COMMISSION...CONSERVATION ACT (âAPPLIANCE LABELING RULEâ) Pt. 305, App. A2 Appendix A2 to Part 305—Refrigerators and Refrigerators-Freezers...

2010-01-01

307

46 CFR 130.230 - Protection from refrigerants.  

Code of Federal Regulations, 2010 CFR

...230 Protection from refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic...stowed convenient to, but outside, the space containing the refrigeration equipment. (c) A complete recharge in the form...

2010-10-01

308

46 CFR 58.20-15 - Installation of refrigerating machinery.  

Code of Federal Regulations, 2010 CFR

...ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Refrigeration Machinery § 58.20-15 Installation of refrigerating...control device located outside the compartment. (c) All refrigeration compressor spaces shall be effectively ventilated and...

2010-10-01

309

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...

310

46 CFR 128.410 - Ship's service refrigeration systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Ship's service refrigeration systems... OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND...Specific Systems § 128.410 Ship's service refrigeration systems...or for refrigerated spaces for ship's stores need comply...

2012-10-01

311

46 CFR 128.410 - Ship's service refrigeration systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Ship's service refrigeration systems... OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND...Specific Systems § 128.410 Ship's service refrigeration systems...or for refrigerated spaces for ship's stores need comply...

2011-10-01

312

Seven-effect absorption refrigeration  

DOEpatents

A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

DeVault, R.C.; Biermann, W.J.

1989-05-09

313

Seven-effect absorption refrigeration  

DOEpatents

A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

DeVault, Robert C. (Knoxville, TN); Biermann, Wendell J. (Fayetteville, NY)

1989-01-01

314

Enantiomeric differentiation of oxygenated p-menthane derivatives by 13C NMR using Yb(hfc)3.  

PubMed

The (13)C NMR behaviour of 21 p-menthanic terpene bearing an oxygenated function (alcohol, ketone, acetate) was examined in the presence of a chiral lanthanide shift reagent (Yb(hfc)(3)). For each monocyclic compound, we measured the lanthanide-induced shift (LIS) on the signals of the carbons and the splitting of signals allowing the enantiomeric differentiation. Some general features were found about their LIS behaviour: experimental data establishing distinct patterns for carvomenthone-like compounds and menthone-like compounds. The enantiomeric splitting was observed for the majority of signals in the spectrum of each compound. In the case of alcohols and acetates, the influence of the relative stereochemistry (cis vs trans) of isopropyl(ene) and the binding function was discussed. PMID:18828150

Lanfranchi, Don Antoine; Blanc, Marie-Cécile; Vellutini, Muriel; Bradesi, Pascale; Casanova, Joseph; Tomi, Félix

2008-12-01

315

Modeling supermarket refrigeration energy use and demand  

SciTech Connect

A computer model has been developed that can predict the performance of supermarket refrigeration equipment to within 3% of field test measurements. The Supermarket Refrigeration Energy Use and Demand Model has been used to simulate currently available refrigerants R-12, R-502 and R-22, and is being further developed to address alternative refrigerants. This paper reports that the model is expected to be important in the design, selection and operation of cost-effective, high-efficiency refrigeration systems. It can profile the operation and performance of different types of compressors, condensors, refrigerants and display cases. It can also simulate the effects of store humidity and temperature on display cases; the efficiency of various floating head pressure setpoints, defrost alternatives and subcooling methods; the efficiency and amount of heat reclaim from refrigeration systems; and the influence of other variables such as store lighting and building design. It can also be used to evaluate operational strategies such as variable-speed drive or cylinder unloading for capacity control. Development of the model began in 1986 as part of a major effort, sponsored by the U.S. electric utility industry, to evaluate energy performance of then conventional single compressor and state-of-the-art multiplex refrigeration systems, and to characterize the contribution of a variety of technology enhancement features on system energy use and demand.

Blatt, M.H.; Khattar, M.K. (Electric Power Research Inst., Palo Alto, CA (US)); Walker, D.H. (Foster Miller Inc., Waltham, MA (US))

1991-07-01

316

Feasibility Study of an Automotive Thermoacoustic Refrigerator  

Microsoft Academic Search

Concerns regarding the environmental impact associated with the use of current vapour-compression refrigeration systems in automobiles have led to the investigation of alternative 'green' technologies. Thermoacoustic refrigera- tion, an emerging 'green' technology based upon the purposeful use of high-pressure sound waves to provide cooling, is the most promising replacement investigated so far. Thermoacoustic refrigerators use environmentally benign gases, are relatively

Luke Zoontjens; Carl Howard; Anthony Zander; Ben Cazzolato

2005-01-01

317

Brownian Refrigerator C. Van den Broeck  

E-print Network

perform a refrigerator function upon loading. We analytically calculate the corresponding heat flow the evaporation by expansion of a cooling liquid in domestic refrigerators, to high-tech meth- ods including laser- terized by a nonzero average speed in a given direction. When both motor units reside in a single

Kawai, Ryoichi

318

Refrigerated display case lighting with LEDs  

Microsoft Academic Search

The rapid development of high brightness light emitting diodes (LEDs) has triggered many applications, especially in the area of display lighting. This paper focuses on the application of white LEDs in refrigerated display cases. The fluorescent lighting presently used in commercial refrigerators is inefficient in the application and also it provides poor lighting for merchandising. A laboratory human factors experiment

Ramesh Raghavan; Nadarajah Narendran

2002-01-01

319

DESIGN AND OPTIMIZATION OF A REFRIGERATION SYSTEM  

EPA Science Inventory

The paper discusses the design and optimization of a refrigeration system, using a mathematical model of a refrigeration system modified to allow its use with the optimization program. he model was developed using only algebraic equations so that it could be used with the optimiz...

320

Commercial Refrigeration Technology. Florida Vocational Program Guide.  

ERIC Educational Resources Information Center

The program guide for commercial refrigeration technology courses in Florida identifies primary considerations for the organization, operation, and evaluation of a vocational education program. Following an occupational description for the job title for refrigeration mechanic, and its Dictionary of Occupational Titles code, are six sections…

University of South Florida, Tampa. Dept. of Adult and Vocational Education.

321

The Thermodynamics of a Refrigeration System.  

ERIC Educational Resources Information Center

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

Azevedo e Silva, J. F. M.

1991-01-01

322

Energy recovery system for refrigeration systems  

Microsoft Academic Search

The invention discloses an energy recovery system for heating water with by-product heat from a refrigeration system wherein a heat exchanger within a refrigerant compressor hot gas conduit may selectively heat water within a storage tank. The flow of water through the storage tank and heat exchanger is controlled by a pump operating during operation of the compressor, preferably, only

Ritchie

1979-01-01

323

Practical concerns for refrigerant management in buildings  

SciTech Connect

In this context, the word practical implies a cross between virtual and economic concerns, and in the case of refrigerant management, the balancing act includes diligence at one end of the scale and cost on the other. The new laws that regulate the HVAC industry are sometimes confusing and carry heavy fines for non-compliance. Even more threatening are potential law suits from someone who can prove that lack of proper refrigerant handling posed a health or safety problem. The guidelines set forth in ASHRAE Standard 15-1992, Safety Code for Mechanical Refrigeration, may not show up in local codes for quite some time, which leaves the question of diligence in the hands of the building owner. The Environmental Protection Agency (EPA) suggests the following measures as a means of getting started with a practical approach to managing refrigerants in buildings: designate a facility refrigerant manager; conduct an inventory of equipment and refrigerants; and develop a refrigerant management plan for maintaining existing equipment, retrofitting equipment to alternative refrigerants, and replacing old or inefficient equipment.

Wylie, D. [ASW Engineering, Tustin, CA (United States)

1995-06-01

324

Pipeline gas pressure reduction with refrigeration generation  

Microsoft Academic Search

The high pressure of pipeline gas is reduced to the low pressure of a distribution system with simultaneous generation of refrigeration by passing the gas through two successive centrifugal compressors driven by two turbo-expanders in which the compressed gas is expanded to successively lower pressures. Refrigeration is recovered from the gas as it leaves each turbo-expander. Methanol is injected into

S. J. Markbreiter; H. P. Schorr

1985-01-01

325

Compatibility of refrigerants and lubricants with elastomers  

SciTech Connect

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.

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

1992-10-01

326

Compatibility of refrigerants and lubricants with elastomers  

SciTech Connect

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.

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

1993-01-01

327

Sorption compressor/mechanical expander hybrid refrigeration  

NASA Technical Reports Server (NTRS)

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.

Jones, J. A.; Britcliffe, M.

1987-01-01

328

Sorption compressor/mechanical expander hybrid refrigeration  

NASA Astrophysics Data System (ADS)

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.

Jones, J. A.; Britcliffe, M.

1987-08-01

329

Dynamic simulation of a reverse Brayton refrigerator  

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

330

Oil cooled, hermetic refrigerant compressor  

DOEpatents

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 and is then delivered through the shell to the top of the motor rotor where most of it is flung radially outwardly within the confined space provided by the cap which channels the flow of most of the oil around the top of the stator and then out to a multiplicity of holes 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 to provide oil cooling of the lower part of the motor, with this oil exiting through vent hole also to the sump. Suction gas with entrained oil and liquid refrigerant therein is delivered to an oil separator from which the suction gas passes by a confined path in pipe to the suction plenum 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. 3 figs.

English, W.A.; Young, R.R.

1985-05-14

331

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, 2011 CFR

...2000 rpm) to circulate refrigerant and oil, and provide some engine and warm-up...refrigerant that is recovered, following oil separation, shall be measured and the quantity...requirement. 7.6The equipment shall separate oil from the refrigerant, measure the...

2011-07-01

332

Mixed refrigerant Joule-Thomson sorption cryocoolers  

NASA Astrophysics Data System (ADS)

Joule-Thomson (JT) sorption cryocooling is the most mature technology for cooling from a normal Room-Temperature (RT) down to temperatures below 100 K in the absence of moving parts. Therefore, high reliability and no vibrations are attainable, in comparison with other cryocoolers. Cooling to 80 - 100 K with JT cryocoolers is often implemented with pure nitrogen. Alternatively, mixed refrigerants have been suggested for reducing the operating pressures to enable closed cycle cryocooling. There is a variety of publications describing nitrogen sorption cryocoolers with different configurations of sorption compressors. In the present research we suggest a novel sorption JT cryocooler that operates with a mixed refrigerant. Merging of sorption cryocooling and a mixed refrigerant enables the use of a simple, single stage compressor for cooling to 80 - 100 K, lower operating temperatures of the sorption cycle, and thus - reduced power consumption. In previous studies we have analyzed sorption compressors for mixed gases and mixed refrigerants for JT cryocoolers, separately. In this paper the option of mixed refrigerant sorption JT cryocoolers is explored. The considerations for developing mixed refrigerants to be driven by sorption compressors and to be utilized with JT cryocoolers are provided. It appears that, unlike with pure nitrogen, mixed refrigerants can be suitable for JT cryocooling with a single stage sorption compressor.

Tzabar, Nir; Grossman, Gershon

2014-01-01

333

Supermarket with Ground Coupled Carbon Dioxide Refrigeration Plant  

E-print Network

) answers? ? Natural refrigerants ? Use of natural heat sinks and sources ? Covered refrigerated shelves ? Waste heat recovery ? Highly insulated building envelope ? Energy efficient heating and ventilating 1. Backgrounds ? Fraunhofer ISE 7 En...) answers? ? Natural refrigerants ? Use of natural heat sinks and sources ? Covered refrigerated shelves ? Waste heat recovery ? Highly insulated building envelope ? Energy efficient heating and ventilating 1. Backgrounds ? Fraunhofer ISE 7 En...

Rehault, N.

2012-01-01

334

IEA Annex 26: Advanced Supermarket Refrigeration\\/Heat Recovery Systems  

Microsoft Academic Search

With increased concern about the impact of refrigerant leakage on global warming, a number of new supermarket refrigeration system configurations requiring significantly less refrigerant charge are being considered. In order to help promote the development of advanced systems and expand the knowledge base for energy-efficient supermarket technology, the International Energy Agency (IEA) established IEA Annex 26 (Advanced Supermarket Refrigeration\\/Heat Recovery

2003-01-01

335

Bearing construction for refrigeration compresssor  

DOEpatents

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.

Middleton, Marc G. (Wyoming, MI); Nelson, Richard T. (Worthington, OH)

1988-01-01

336

Quantum-enhanced absorption refrigerators  

E-print Network

Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step t...

Correa, Luis A; Alonso, Daniel; Adesso, Gerardo

2014-01-01

337

Dual-circuit, multiple-effect refrigeration system and method  

DOEpatents

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.

DeVault, Robert C. (Knoxville, TN)

1995-01-01

338

Bypass and monitoring circuit for refrigeration system  

SciTech Connect

A bypass and monitoring circuit is described for use with a refrigeration system having means to sense a need to initiate a defrost cycle and means to reset the defrost cycle upon sensing the defrosting of the refrigeration system. The circuit comprises: first means to sense whether the duration of each defrost cycle exceeds a certain period; and second means, responsive to the first means sensing that the duration of a given cycle exceeded the certain period, for electrically decoupling the reset means from the refrigeration system, for resetting the given defrost cycle and for enabling the occurrence of and controlling the duration of subsequent defrost cycle.

Kyzer, G.; Smollon, J.

1987-05-19

339

Mathematical analysis of a Vuilleumier refrigerator.  

NASA Technical Reports Server (NTRS)

A comprehensive analysis of the Vuilleumier refrigerator was conducted. This analysis includes the effects of nonisothermal gas heat addition and rejection, hot and cold regenerator inefficiencies, conduction losses, and gas leakage losses. A computer program was written which solves the equations resulting from the analysis. The program calculates internal pressures, temperatures, and gas flow rates as functions of refrigerator crank angle, as well as overall refrigerator cooling load and power input. Comparisons between the program results and available data show good agreement, with a marked improvement over the predictions of the ideal model.

Sherman, A.

1971-01-01

340

Sorption cryogenic refrigeration - Status and future  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.

1988-01-01

341

Space shuttle orbiter mechanical refrigeration system  

NASA Technical Reports Server (NTRS)

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

Williams, J. L.

1974-01-01

342

Life Cycle Inventory Analysis of the Production of a High-performance Foam Blowing Agent HFC245fa (1,1,1,3,3-pentafluoropropane)  

Microsoft Academic Search

A life cycle inventory analysis is described for the production of HFC-245fa (1,1,1,3,3-pentafluoropropane) from basic raw materials to the pure product ready for shipment to customers. The analysis was based on typical industrial operations, assumed to be located in southern USA. It showed the mineral requirements to be mainly salt, fluorspar, sulphur, and limestone, together with natural gas and oil

Archie Mcculloch

2010-01-01

343

Technical and Economical Demands on 25K - 77K Refrigerators for Future HTS — Series Products in Power Engineering  

NASA Astrophysics Data System (ADS)

For the future high temperature superconductivity, HTS, series products new refrigerators are essential. Demands are made on these which are only partly fulfilled by refrigerators available in the market today. This refers to cooling power, initial cost and in particular reliability. Without proper refrigeration techniques it will be almost impossible to bring HTS products to the market. Based on the experiences made by the construction and operation of HTS prototypes within our company, like the 400 kW motor, 1.2 MVA current limiter and 1 MVA traction-transformer provided with refrigerators which are available in the market today, criteria have been established to identify the future technical and economical requirements. These criteria apply to efficiency, maintainability, operation flexibility, feasibility of integration and performance/cost ratio. For the temperature range of 20 K to 77 K cooling with Gifford-McMahon, Pulse Tube, Stirling and Mixture-Cascade refrigerators are applicable. The development potential of these processes are compared for the different applications in future series products. Presented are the necessary steps towards reliable and economic refrigerators from the viewpoint of an equipment manufacturer. These are essential for a market entry in the year 2008.

Gromoll, B.

2004-06-01

344

Compatibility of refrigerants and lubricants with engineering plastics  

SciTech Connect

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.

Cavestri, R.C.

1993-01-01

345

Application of Cascade Refrigeration System with Mixing Refrigerant in Cold Air Cutting  

NASA Astrophysics Data System (ADS)

In the mechanical cutting process, the replacement of traditional cutting solution with cold air can avoid the pollution of environment. In order to high efficient the refrigerating device and flexible adjust the temperature of cold air, it is necessary to use cascade refrigeration system to supply cool quantity for the compressed air. The introduction of a two-component non-azeotropic mixing refrigerant into the cryogenic part of the cascade system, can effectively solve the problems of the system working at too high pressure and the volume expanding of refrigerant in case of the cascade refrigeration sets closed down. However, the filling ratio of mixing refrigerants impact on the relationships among the closing down pressure, refrigerating output and refrigerating efficiency. On the basis of computing and experiment, the optimal mixing ratio of refrigerant R22/R13 and a low temperature of -60° were obtained in this study. A cold air injecting device possessing high efficiency in energy saving has also been designed and manufactured. The cold air, generated from this cascade system and employed in a cutting process, takes good comprehensive effects on machining and cutting.

Yang, Y.; Tong, M. W.; Yang, G.; Wang, X. P.

346

Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration  

SciTech Connect

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.

Bansal, Pradeep [ORNL; Vineyard, Edward Allan [ORNL; Abdelaziz, Omar [ORNL

2012-01-01

347

Vaccine refrigeration: thinking outside of the box.  

PubMed

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

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

2014-04-01

348

Intra-molecular refrigeration in enzymes  

E-print Network

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.

Hans J. Briegel; Sandu Popescu

2009-12-14

349

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

350

Shuttle kit freezer refrigeration unit conceptual design  

NASA Technical Reports Server (NTRS)

The refrigerated food/medical sample storage compartment as a kit to the space shuttle orbiter is examined. To maintain the -10 F in the freezer kit, an active refrigeration unit is required, and an air cooled Stirling Cycle refrigerator was selected. The freezer kit contains two subsystems, the refrigeration unit, and the storage volume. The freezer must provide two basic capabilities in one unit. One requirement is to store 215 lbs of food which is consumed in a 30-day period by 7 people. The other requirement is to store 128.3 lbs of medical samples consisting of both urine and feces. The unit can be mounted on the lower deck of the shuttle cabin, and will occupy four standard payload module compartments on the forward bulkhead. The freezer contains four storage compartments.

Copeland, R. J.

1975-01-01

351

Refrigeration system having standing wave compressor  

DOEpatents

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.

Lucas, Timothy S. (Glen Allen, VA)

1992-01-01

352

21 CFR 1250.34 - Refrigeration equipment.  

Code of Federal Regulations, 2013 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment. Each...

2013-04-01

353

21 CFR 1250.34 - Refrigeration equipment.  

Code of Federal Regulations, 2012 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment. Each...

2012-04-01

354

21 CFR 1250.34 - Refrigeration equipment.  

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment. Each...

2014-04-01

355

21 CFR 1250.34 - Refrigeration equipment.  

Code of Federal Regulations, 2011 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Food Service Sanitation on Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment. Each...

2011-04-01

356

Defrost Temperature Termination in Supermarket Refrigeration Systems  

SciTech Connect

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.

Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

2011-11-01

357

Magnetic refrigeration: the promise and the problems  

SciTech Connect

Magnetic refrigeration uses the temperature- and field-dependence of the entropy of some magnetic materials to accomplish cooling. Because of the intrinsically high efficiency of the magnetization and demagnetization process and because of the potential for excellent heat transfer between solids and fluids, magnetic refrigerators promise to have higher efficiency than existing gas-cycle refrigerators. Many ground-based and space-based applications could benefit significantly from the cost savings implied by higher efficiency. Other attributes of these devices are high reliability and low volume and mass per unit cooling power. The development of these refrigerators is underway at several places around the world, including the Los Alamos National Laboratory. The progress to date has been encouraging but some problems have been clearly identified. The arguments for high efficiency and the problems that will need to be solved to achieve this goal are discussed.

Barclay, J.A.

1984-01-01

358

Simulation of the Energy Saver refrigeration system  

SciTech Connect

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.

Barton, H.R. Jr.; Nicholls, J.E.; Mulholland, G.T.

1981-10-01

359

Elastic Metal Alloy Refrigerants: Thermoelastic Cooling  

SciTech Connect

BEETIT Project: UMD is developing an energy-efficient cooling system that eliminates the need for synthetic refrigerants that harm the environment. More than 90% of the cooling and refrigeration systems in the U.S. today use vapor compression systems which rely on liquid to vapor phase transformation of synthetic refrigerants to absorb or release heat. Thermoelastic cooling systems, however, use a solid-state material—an elastic shape memory metal alloy—as a refrigerant and a solid to solid phase transformation to absorb or release heat. UMD is developing and testing shape memory alloys and a cooling device that alternately absorbs or creates heat in much the same way as a vapor compression system, but with significantly less energy and a smaller operational footprint.

None

2010-10-01

360

Performance evaluation of heat exchanger for mixed refrigerant J-T cryocooler  

NASA Astrophysics Data System (ADS)

In mixed refrigerant Joule-Thomson cryocooler, a multi-component mixture of nitrogen-hydrocarbons undergoes evaporation and condensation process in a helical coiled heat exchanger simultaneously at different pressures. Experimental data and empirical correlations for predicting heat transfer coefficients of evaporating and condensing streams of multi-component mixtures at cryogenic temperatures are unavailable. As a result, design of these heat exchangers is a challenging task. The present work aims to address this challenge. It assesses the existing condensation correlations against the calculated data obtained during experimentation. Experiments are conducted to determine overall heat transfer coefficients along the length of the heat exchanger for various mixtures. The paper studies the applicability of these correlations to the multi-component mixtures at cryogenic temperatures.

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

2014-09-01

361

Combined cold compressor/ejector helium refrigerator  

DOEpatents

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.

Brown, D.P.

1984-06-05

362

Magnetic refrigeration in space - Practical considerations  

NASA Technical Reports Server (NTRS)

Various schemes of using adiabatic demagnetization to provide refrigeration in the 10-1000 mK range are discussed with particular reference to the requirements for use in space. The methods considered are complete demagnetization, isothermal demagnetization, moving magnet demagnetization, and continuous refrigeration. The requirements that are important for use in space are low mass, low power dissipation, high mechanical rigidity, modular design, and ease of use.

Kittel, P.

1980-01-01

363

Combined cold compressor/ejector helium refrigerator  

DOEpatents

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.

Brown, Donald P. (Southold, NY)

1985-01-01

364

Acute lung injury following refrigeration coil deicing.  

PubMed

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

McKeown, Nathanael J; Burton, Brent T

2012-03-01

365

Retrofit cogeneration system increases refrigeration capacity  

SciTech Connect

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.

Amberger, R.F. (Modern Energy Technology Corp., Rochester, NY (United States)); DeFrees, J.A. (Fleming Group, Syracuse, NY (United States))

1993-04-01

366

Method and apparatus for preventing overheating of the superheated vapors in a solar heating system using a refrigerant  

SciTech Connect

This invention relates to an improved method and apparatus for preventing overheating of the superheated vapors in a solar heating system using a refrigerant to collect heat from the atmosphere, the improvement consisting of sensing the amount of superheat contained in the superheated vapors leaving the collector and if an overheated condition is detected, bleeding off a portion of the refrigerant mixture entering the collector and mixing it with the overheated vapors to cool them down before they enter the compressor. The apparatus involved includes a thermostatic expansion valve responsive to the temperature of the superheated vapors leaving the collector and associated piping operative upon actuation to bypass a portion of the refrigerant mixture entering the collector around the later and mix it with the overheated vapors before they reach the compressor. The invention also encompasses the use of the improved desuperheating method and apparatus outlined above in such a way that it only becomes functional and operative when the conventional solar system is already activated to deliver the full charge of refrigerant mixture to the collectors.

Weis, F.A.

1980-10-07

367

Boiling of multicomponent liquid mixtures  

SciTech Connect

This article reviews the significant advances in the understanding of the boiling process germane to mixtures. The scope of this review is limited to miscible systems. The effects of impurities (such as lubricating oils in refrigerants), surfactants, soluble salts, and dissolved gases are excluded from consideration. Both pool and convective boiling are addressed. The ultimate goals of the study of boiling of liquid mixtures are: to predict the superheat required for the inception of boiling, to predict their heat transfer coefficients with a reasonable degree of accuracy, and to predict the variation in the peak nucleate and dry out heat fluxes with composition. These goals are closer to being met for pool boiling than they are for convective boiling. The topics discussed in this survey are presented in much the same order as when an increasing heat flux is applied to a surface to cause boiling. Thus bubble nucleation or boiling incipience is considered first, since this defines the criteria required for boiling to commence. Then the growth of the vapor bubbles from vapor nuclei up to and including their departure from the surface is discussed. This is followed by a survey of the heat transfer mechanisms, resulting from the vaporization process, which affect the nucleate pool boiling curve, and this leads to a discussion of equations for predicting nucleate pool boiling heat transfer coefficients. The peak nucleate heat flux in pool boiling is examined prior to a description of film boiling. Several aspects of convective boiling are then presented.

Thome, J.R.; Shock, R.A.W.

1984-01-01

368

Computer modeling of commercial refrigerated warehouse facilities  

SciTech Connect

The use of computer models to simulate the energy performance of large commercial refrigeration systems typically found in food processing facilities is an area of engineering practice that has seen little development to date. Current techniques employed in predicting energy consumption by such systems have focused on temperature bin methods of analysis. Existing simulation tools such as DOE2 are designed to model commercial buildings and grocery store refrigeration systems. The HVAC and Refrigeration system performance models in these simulations tools model equipment common to commercial buildings and groceries, and respond to energy-efficiency measures likely to be applied to these building types. The applicability of traditional building energy simulation tools to model refrigerated warehouse performance and analyze energy-saving options is limited. The paper will present the results of modeling work undertaken to evaluate energy savings resulting from incentives offered by a California utility to its Refrigerated Warehouse Program participants. The TRNSYS general-purpose transient simulation model was used to predict facility performance and estimate program savings. Custom TRNSYS components were developed to address modeling issues specific to refrigerated warehouse systems, including warehouse loading door infiltration calculations, an evaporator model, single-state and multi-stage compressor models, evaporative condenser models, and defrost energy requirements. The main focus of the paper will be on the modeling approach. The results from the computer simulations, along with overall program impact evaluation results, will also be presented.

Nicoulin, C.V.; Jacobs, P.C.; Tory, S.

1997-07-01

369

GEA Refrigeration Technologies / GEA Refrigeration Germany GmbH Wolfgang Dietrich / Dr. Ole Fredrich  

E-print Network

Refrigeration Technologies Single stage heat pump ­ a "combined system" Achema 2012 // heat pumps using ammonia9 Fredrich GEA Grasso heat pumps using ammonia ­ the megawatt range #12;GEA Refrigeration Technologies2 Achema 2012 // heat pumps using ammonia Heat pumps using ammonia ­ a sustainable choice How to improve

Oak Ridge National Laboratory

370

Method of operating a transport refrigeration system  

SciTech Connect

A method of enhancing the defrost cycle of a truck refrigeration system which lacks a dedicated prime mover of the internal combustion type, is described comprising the steps of: providing a transport refrigeration system having a first compressor operatively coupled to the engine of the associated truck, a second compressor operatively coupled to an electric motor, and a single refrigeration circuit including a condenser, evaporator, accumulator, and valve means operable to provide cooling and defrost cycles utilizing the discharge gas of one of the compressors, using the discharge gas of the first compressor in the single refrigeration circuit when the truck engine is operating, connecting the electric motor to an electrical stand-by source when the truck engine is not operating, using the discharge gas of the second compressor in the single refrigeration circuit when the electrical motor is connected to the electrical stand-by source, providing heat storage means in heat exchange relation with the accumulator, and providing electrical resistance means for continuously storing heat in the heat storage means while the single refrigeration circuit is connected to either one of the first and second compressors, at the lowest heat storage rate which will provide adequate heat build up between defrost cycles to vaporize liquified refrigerant introduced into the accumulator during a defrost cycle, the step of providing electrical resistance means including the steps of: connecting the electrical resistance means to the electrical system of the associated truck when the first compressor is operative, and connecting the electrical resistance means to an electrical stand-by source when the second compressor is operative.

Howland, L.L.

1988-01-26

371

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...

372

A Superfluid Pulse Tube Refrigerator Without Moving Parts for Sub-Kelvin Cooling  

NASA Technical Reports Server (NTRS)

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.

Miller, Franklin K.

2012-01-01

373

Potential Refrigerants for Power Electronics Cooling  

SciTech Connect

In the past, automotive refrigerants have conventionally been used solely for the purpose of air conditioning. However, with the development of hybrid-electric vehicles and the incorporation of power electronics (PEs) into the automobile, automotive refrigerants are taking on a new role. Unfortunately, PEs have lifetimes and functionalities that are highly dependent on temperature and as a result thermal control plays an important role in the performance of PEs. Typically, PEs are placed in the engine compartment where the internal combustion engine (ICE) already produces substantial heat. Along with the ICE heat, the additional thermal energy produced by PEs themselves forces designers to use different cooling methods to prevent overheating. Generally, heat sinks and separate cooling loops are used to maintain the temperature. Disturbingly, the thermal control system can consume one third of the total volume and may weigh more than the PEs [1]. Hence, other avenues have been sought to cool PEs, including submerging PEs in automobile refrigerants to take advantage of two-phase cooling. The objective of this report is to explore the different automotive refrigerants presently available that could be used for PE cooling. Evaluation of the refrigerants will be done by comparing environmental effects and some thermo-physical properties important to two-phase cooling, specifically measuring the dielectric strengths of potential candidates. Results of this report will be used to assess the different candidates with good potential for future use in PE cooling.

Starke, M.R.

2005-10-24

374

Cold chain: solar refrigerator field tested.  

PubMed

The Health Ministries of Colombia and Peru, in collaboration with the Expanded Program on Immunization (EPI)/Pan American Health Organization (PAHO) and the Centers for Disease Control (CDC), have begun field testing a solar-powered vaccine refrigerator. The aim of the fields trials is to determine whether solar refrigerators can maintain the temperatures required for vaccine storage (+4-8 degrees Celsius) and produce ice at a rate of 2 kg/24 hours under different environmental conditions. these refrigerators would be particularly useful in areas that lack a consistent supply of good quality fuel or where the electrical supply is intermittent or nonexistent. Full appraisal of this technology will require 2 years of field testing; Colombia and Peru expect to complete testing in 1985. To date, 5 models have passed CDC-developed specifications, all of which are manufactured in the US. PAHO/WHO recommends that health ministries should consider the following guidelines in considering the purchase of a particular system: the initial purchase should be for a limited quantity (about 5) of refrigerators to permit field testing; solar panels should meet specific criteria; consideration should be given only to those models that have passed qualification tests; each unit should be fully equipped with monitoring devices and spare parts; and a trained refrigerator technician should be available to repair the equipment. PMID:12314506

1983-04-01

375

Quantum heat engines and refrigerators: continuous devices.  

PubMed

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 ?c and heat capacity cV of the cold bath. PMID:24689798

Kosloff, Ronnie; Levy, Amikam

2014-01-01

376

Refrigerator DSM programs: Status and prospects  

SciTech Connect

The energy use of new refrigerators in the US has decreased by nearly 50 percent since 1980, driven by federal standards and utility demand-side management (DSM) programs. With today`s new refrigerators so much more efficient than earlier products, are refrigerators still an attractive target for demand-side management efforts? An E Source analysis of US utility programs reveals the following: (1) The retirement of older, inefficient refrigerators from homes with two or more units is generally a cost-effective DSM approach, with savings of about 1,000 kWh per year for every spare unit that is eliminated from use and not replaced with a new model. (2) Hundreds of new models exceed federal efficiency standards by at least 10 percent, using 50 to 300 kWh per year less than the standards allow. Modest incentives for these machines can still be cost-effective for some utilities, although many rebate programs have been dropped. (3) More utilities are targeting rebates and other incentives ``upstream`` to retailers or manufacturers as a means of increasing the leverage of DSM investments. (4) Multi-utility efforts, such as the establishment of uniform performance targets by several utilities, can be more effective than individual utility programs in moving the market for higher efficiency refrigerators, and are getting increasing attention.

George, K.L.; Shepard, M.

1994-12-31

377

Quantum Heat Engines and Refrigerators: Continuous Devices  

NASA Astrophysics Data System (ADS)

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.

Kosloff, Ronnie; Levy, Amikam

2014-04-01

378

Cool sound: the future of refrigeration? Thermodynamic and heat transfer issues in thermoacoustic refrigeration  

NASA Astrophysics Data System (ADS)

During the past two decades the thermoacoustic refrigeration and prime mover cycles gained importance in a variety of refrigeration applications. Acoustic work, sound, can be used to generate temperature differences that allow the transport of heat from a low temperature reservoir to an ambient at higher temperature, thus forming a thermoacoustic refrigeration system. The thermoacoustic energy pumping cycle can also be reversed: temperature difference imposed along the stack plates can lead to sound generation. In this situation the thermoacoustic system operates as a prime mover. Sound generated by means of this thermoacoustic energy conversion process can be utilized to drive different types of refrigeration devices that require oscillatory flow for their operation, such as thermoacoustic refrigerators, pulse tubes and Stirling engines. In order for a thermoacoustic refrigeration or prime mover system as well as a thermoacoustic prime mover driving a non-thermoacoustic refrigeration system to be competitive on the current market, it has to be optimized in order to improve its overall performance. Optimization can involve improving the performance of the entire system as well as its components. The paper addresses some of the thermodynamic and heat transfer issues relevant in improving the performance of the thermoacoustic system, such as optimization for maximum COP, maximum cooling load and the role of the heat exchangers. Results obtained using the two optimization criteria are contrasted in the paper to illustrate the complexity of the optimization process.

Herman, C.; Travnicek, Z.

2006-04-01

379

Radiation properties and sound quality characteristics of refrigerator noise  

NASA Astrophysics Data System (ADS)

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.

Jeon, Jin Yong; Jeong, Jeong Ho; You, Jin

2005-09-01

380

OPTIONS FOR REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS  

EPA Science Inventory

The report was prepared to assist personnel responsible for the design, construction, and maintenance of retail food refrigeration equipment in making knowledgeable decisions regarding the implementation of refrigerant-emissions-reducing practices and technologies. It characteriz...

381

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...

382

46 CFR 98.25-35 - Refrigerated systems.  

Code of Federal Regulations, 2010 CFR

...temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically regulated by pressure variations...necessary auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to maintain the vapor...

2010-10-01

383

46 CFR 128.410 - Ship's service refrigeration systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Ship's service refrigeration systems. 128.410 Section 128.410 Shipping ...Requirements for Specific Systems § 128.410 Ship's service refrigeration systems. No self-contained unit either for...

2010-10-01

384

Fully portable, highly flexible dilution refrigerator systems for neutron scattering  

E-print Network

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

Boyer, Edmond

385

Thermoelectric refrigerator having improved temperature-stabilization means  

SciTech Connect

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.

Falco, C.M.

1981-07-29

386

Motor Frame Cooling with Hot Liquid Refrigerant and Internal Liquid.  

National Technical Information Service (NTIS)

This invention presents the device and method for cooling electric machines with hot liquid refrigerant in a floating refrigerant loop and using an internal liquid such as oil for enhancing the cooling effects. The electric machine cooling apparatus has a...

J. S. Hsu, C. W. Ayers, C. Coomer

2005-01-01

387

Proposed Methodology for LEED Baseline Refrigeration Modeling (Presentation)  

SciTech Connect

This PowerPoint presentation summarizes a proposed methodology for LEED baseline refrigeration modeling. The presentation discusses why refrigeration modeling is important, the inputs of energy models, resources, reference building model cases, baseline model highlights, example savings calculations and results.

Deru, M.

2011-02-01

388

Load leveling on industrial refrigeration systems  

NASA Astrophysics Data System (ADS)

A computer model was constructed of a brewery with a 2000 horsepower compressor/refrigeration system. The various conservation and load management options were simulated using the validated model. The savings available for implementing the most promising options were verified by trials in the brewery. Result show that an optimized methodology for implementing load leveling and energy conservation consisted of: (1) adjusting (or tuning) refrigeration systems controller variables to minimize unnecessary compressor starts, (2) The primary refrigeration system operating parameters, compressor suction pressure, and discharge pressure are carefully controlled (modulated) to satisfy product quality constraints (as well as in-process material cooling rates and temperature levels) and energy evaluating the energy cost savings associated with reject heat recovery, and (4) a decision is made to implement the reject heat recovery system based on a cost/benefits analysis.

Bierenbaum, H. S.; Kraus, A. D.

1982-01-01

389

An analytical model for regenerative refrigerators  

NASA Astrophysics Data System (ADS)

An analytical model for regenerative refrigerators is given. The model has two main features: (1) establish the models of parts, including regenerator, heat exchanger, working volume, etc., individually, then, relate all parts by the boundary conditions. (2) the equation of model is reduced to a set of linear algebraic equations. In the model, the interaction of all parts, the cyclic flow and heat transfer of regenerators and heat exchangers and limited heat transfer of working volumes, effect of real gas, etc, are considered simultaneously. In addition, the numerical results of a Vuilleumier refrigerator with power being supplied by liquid nitrogen are compared with the Schmidt model and the experimental results. The model provides a better understanding of the working mechanism of regenerative refrigerators.

Jian-Feng, Wu; Yuan, Zhou

390

Analysis of magnetic refrigerators with external regeneration  

SciTech Connect

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.

Overton, W.C. Jr.; Barclay, J.A.

1986-01-01

391

THE REFRIGERATION TREATMENT OF CHRONIC OSTEOMYELITIS  

PubMed Central

Systemic penicillin therapy plus refrigeration at the site of the lesion, with operation if necessary, was used in the treatment of chronic osteomyelitis. Nine patients with disease of long standing were treated. For three, bed rest, chemotherapy and refrigeration were sufficient. Surgical treatment in addition was carried out in six cases. Operations consisted of unroofing the abscess cavity, multiple drilling for sievelike perforation of the abscessed bone, and primary suture of the incision. Solutions of penicillin, 500 to 1,000 units per cubic centimeter, were used for local irrigation at the time of closure. In all cases the lesions healed and there was no recurrence within a period of two years. The period of hospitalization did not exceed 14 days in any case. Refrigeration of the infected area before and after operation reduced pain, swelling, infection and toxemia. PMID:14801722

Bingham, Robert

1951-01-01

392

Toxicity Data to Determine Refrigerant Concentration Limits  

SciTech Connect

This report reviews toxicity data, identifies sources for them, and presents resulting exposure limits for refrigerants for consideration by qualified parties in developing safety guides, standards, codes, and regulations. It outlines a method to calculate an acute toxicity exposure limit (ATEL) and from it a recommended refrigerant concentration limit (RCL) for emergency exposures. The report focuses on acute toxicity with particular attention to lethality, cardiac sensitization, anesthetic and central nervous system effects, and other escape-impairing effects. It addresses R-11, R-12, R-22, R-23, R-113, R-114, R-116, R-123, R-124, R-125, R-134, R-134a, R-E134, R-141b, R-142b, R-143a, R-152a, R-218, R-227ea, R-236fa, R-245ca, R-245fa, R-290, R-500, R-502, R-600a, R-717, and R-744. It summarizes additional data for R-14, R-115, R-170 (ethane), R-C318, R-600 (n-butane), and R-1270 (propylene) to enable calculation of limits for blends incorporating them. The report summarizes the data a nd related safety information, including classifications and flammability data. It also presents a series of tables with proposed ATEL and RCL concentrations-in dimensionless form and the latter also in both metric (SI) and inch-pound (IP) units of measure-for both the cited refrigerants and 66 zerotropic and azeotropic blends. They include common refrigerants, such as R-404A, R-407C, R-410A, and R-507A, as well as others in commercial or developmental status. Appendices provide profiles for the cited single-compound refrigerants and for R-500 and R-502 as well as narrative toxicity summaries for common refrigerants. The report includes an extensive set of references.

Calm, James M.

2000-09-30

393

Pipeline gas pressure reduction with refrigeration generation  

SciTech Connect

The high pressure of pipeline gas is reduced to the low pressure of a distribution system with simultaneous generation of refrigeration by passing the gas through two successive centrifugal compressors driven by two turbo-expanders in which the compressed gas is expanded to successively lower pressures. Refrigeration is recovered from the gas as it leaves each turbo-expander. Methanol is injected into the pipeline gas before it is expanded to prevent ice formation. Aqueous methanol condensate separated from the expanded gas is distilled for the recovery and reuse of methanol.

Markbreiter, S. J.; Schorr, H. P.

1985-06-11

394

Helium refrigeration considerations for cryomodule design  

NASA Astrophysics Data System (ADS)

Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads.

Ganni, V.; Knudsen, P.

2014-01-01

395

Entanglement enhances cooling in microscopic quantum refrigerators  

NASA Astrophysics Data System (ADS)

Small self-contained quantum thermal machines function without external source of work or control but using only incoherent interactions with thermal baths. Here we investigate the role of entanglement in a small self-contained quantum refrigerator. We first show that entanglement is detrimental as far as efficiency is concerned—fridges operating at efficiencies close to the Carnot limit do not feature any entanglement. Moving away from the Carnot regime, we show that entanglement can enhance cooling and energy transport. Hence, a truly quantum refrigerator can outperform a classical one. Furthermore, the amount of entanglement alone quantifies the enhancement in cooling.

Brunner, Nicolas; Huber, Marcus; Linden, Noah; Popescu, Sandu; Silva, Ralph; Skrzypczyk, Paul

2014-03-01

396

Electronic refrigeration at the quantum limit.  

PubMed

We demonstrate quantum-limited electronic refrigeration of a metallic island in a low-temperature microcircuit. We show that matching the impedance of the circuit enables refrigeration at a distance, of about 50 microm in our case, through superconducting leads with a cooling power determined by the quantum of thermal conductance. In a reference sample with a mismatched circuit this effect is absent. Our results are consistent with the concept of electromagnetic heat transport. We observe and analyze the crossover between electromagnetic and quasiparticle heat flux in a superconductor. PMID:19519012

Timofeev, Andrey V; Helle, Meri; Meschke, Matthias; Möttönen, Mikko; Pekola, Jukka P

2009-05-22

397

An analytical screening of alternatives for R-502 in low-temperature refrigerating applications  

NASA Astrophysics Data System (ADS)

R-502 is used as the working fluid of low-temperature refrigerating systems with evaporating temperatures as low as -40 F (-40 C). It was selected as the refrigerant of choice for these applications because it is both nonflammable and nontoxic and has an acceptable compressor discharge temperature when used in a high-efficiency vapor-compression system. Replacement fluids are going to be needed for use in place of R-502, however, because of the provisions of the Montreal Protocol. R-502 is an azeotropic blend of R-22 and R-115, and R-115 is a chlorofluorocarbon (CFC). The provisions of the Montreal Protocol currently require a total phase-out of the production of all fully halogenated CFCs, including R-115, by the year 2000. Consequently, replacement fluids will be needed for new and existing equipment. This study was initiated to identify other possible fluids that can be used either in new or retrofit applications for low-temperature refrigerant. It includes an evaluation of predicted cycle efficiency, system capacity, pressure ratio, fluid flammability, and compressor discharge temperature. Eight different chemical compounds are considered for use as pure refrigerants as well as components in binary and ternary mixtures: R-134a, R-134, R-125, R-143a, R-152a, R-32, R-124, and R-22. An exhaustive study of the composition of blends was performed to determine the mass fractions of each component in the mixtures that are most promising on the basis of efficiency, flammability, low discharge temperature, and acceptable capacity and pressure ratio. Several blends are identified for further laboratory and analytical evaluation.

Fischer, S. K.

398

Method and apparatus for de-superheating refrigerant  

DOEpatents

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

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

1997-11-25

399

Adsorption refrigeration research in Shanghai Jiao Tong University  

Microsoft Academic Search

The research work on adsorption refrigeration in Shanghai Jiao Tong University (SJTU) started in 1993, various adsorption refrigeration cycles have been investigated, such as continuous heat recovery cycle, mass recovery cycle, thermal wave cycle, convective thermal wave cycle, cascade multi effect cycle, hybrid heating and cooling cycle etc. Several prototype adsorption refrigeration systems have been developed and tested, typical examples

R. Z. Wang

2001-01-01

400

Refrigerator Recycling Evaluation Protocol Doug Bruchs, The Cadmus Group, Inc.  

E-print Network

1 Refrigerator Recycling Evaluation Protocol Doug Bruchs, The Cadmus Group, Inc. Refrigerator recycling programs have become a staple of residential demand-side management portfolios. 1 Measure Description Refrigerator recycling programs are designed to save energy through the removal of old

401

Commissioning and operation of the CEBAF end station refrigeration system.  

National Technical Information Service (NTIS)

The CEBAF End Station Helium Refrigerator (ESR) System provides refrigeration at 80 K, 20 K, and 4.5 K to three End Station experimental halls. The facility consists of a two stage helium screw compressor system, 4.5 K refrigerator, cryogen distribution v...

D. Arenius, B. Bevins, W. C. Chronis, V. Ganni, D. Kashy

1996-01-01

402

Lubricity effect of carbon dioxide used as an environmentally friendly refrigerant in air-conditioning and refrigeration compressors  

Microsoft Academic Search

Environmental concerns have increased the interest in alternative natural refrigerants for air-conditioning and refrigeration compressors. Carbon dioxide (CO2) or R744 is an attractive candidate to replace harmful hydrofluorocarbon refrigerants, which will need to be replaced in the near future due to their high global warming potential. In this paper the tribological behavior of gray cast iron in the presence of

Emerson Escobar Nunez; Kyriaki Polychronopoulou; Andreas A. Polycarpou

2010-01-01

403

Carbon Dioxide and Ionic Liquid Refrigerants: Compact, Efficient Air Conditioning with Ionic Liquid-Based Refrigerants  

SciTech Connect

BEETIT Project: Notre Dame is developing an air-conditioning system with a new ionic liquid and CO2 as the working fluid. Synthetic refrigerants used in air conditioning and refrigeration systems are potent GHGs and can trap 1,000 times more heat in the atmosphere than CO2 alone—making CO2 an attractive alternative for synthetic refrigerants in cooling systems. However, operating cooling systems with pure CO2 requires prohibitively high pressures and expensive hardware. Notre Dame is creating a new fluid made of CO2 and ionic liquid that enables the use of CO2 at low pressures and requires minimal changes to existing hardware and production lines. This new fluid also produces no harmful emissions and can improve the efficiency of air conditioning systems— enabling new use of CO2 as a refrigerant in cooling systems.

None

2010-10-01

404

CFD simulation of refrigerated display cabinets  

Microsoft Academic Search

The finite element method is employed for the analysis of velocity and temperature distributions in refrigerated open display cabinets. The CFD code is based on the streamfunction-vorticity formulation, and incorporates a LES turbulence model. As an example of application, a vertical multi-deck cabinet is investigated under different operating conditions. The numerical results have been validated by comparison with experimental tests

Giovanni Cortella; Marco Manzan; Gianni Comini

2001-01-01

405

Refrigeration or heat pump system defrost  

SciTech Connect

Disclosed is a refrigeration or heat pump system comprising an evaporator coil and apparatus for initiating the defrost cycles of the evaporator coil at a frequency proportional to the difference between a water vapor pressure in air in the evaporator coil environment and a saturation water vapor pressure corresponding to the evaporator coil temperature.

Bonne, V.

1985-12-31

406

Waste Heat Recapture from Supermarket Refrigeration Systems  

Microsoft Academic Search

The objective of this project was to determine the potential energy savings associated with improved utilization of waste heat from supermarket refrigeration systems. Existing and advanced strategies for waste heat recovery in supermarkets were analyzed, including options from advanced sources such as combined heat and power (CHP), micro-turbines and fuel cells.

Fricke; Brian A

2011-01-01

407

Natural Refrigerant, Geothermal Heating & Cooling Solutions  

E-print Network

Natural Refrigerant, Geothermal Heating & Cooling Solutions Lalit Chordia, PhD, Marc Portnoff 150 · Significantly less expensive · Does not affect the ozone layer · Orders of magnitude less impact on global)? 0 500 1000 1500 2000 2500 3000 3500 R22 R134A R404A R410A R744 (CO2) GWP Global

408

REFRIGERANT CONCENTRATIONS IN MOTOR VEHICLE PASSENGER COMPARTMENTS  

EPA Science Inventory

Refrigerant leak rates were measured for faulty air-conditioner evaporators removed from vehicles, and results indicated a range of very small to very large leaks. A survey of automotive air-conditioning service shops was conducted, and leakage scenarios were evaluated to determi...

409

Fundamentals of Air Conditioning and Refrigeration.  

ERIC Educational Resources Information Center

This set of instructional materials provides secondary and postsecondary students with a state-of-the-art curriculum for the air conditioning and refrigeration industry that includes the many changes brought by new Environmental Protection Agency (EPA) regulations. Introductory materials explain the use of this publication and provide the…

Clemons, Mark

410

Air Conditioning and Refrigeration Book IV.  

ERIC Educational Resources Information Center

This publication is the concluding text in a four-part curriculum for air conditioning and refrigeration. Materials in Book 4 are designed to complement theoretical and functional elements in Books 1-3. Instructional materials in this publication are written in terms of student performance using measurable objectives. The course includes six…

Eckes, William; Fulkerson, Dan

411

Air Conditioning and Refrigeration. Book One.  

ERIC Educational Resources Information Center

Designed to provide students with the basic skills for an occupation in air conditioning and refrigeration, this curriculum guide includes seven major areas, each consisting of one or more units of instruction. These areas and their respective units are titled as follows: Orientation (history and development, and job opportunities), Safety…

Wantiez, Gary W.

412

Saturated Vapour Pressure and Refrigeration - Part I  

ERIC Educational Resources Information Center

The first part of a two-part article describes an experimental approach that can be used in teaching the concept of saturated vapour pressure. This leads to a discussion of refrigeration cycles in the second part of the article. (JR)

Bunker, C. A.

1973-01-01

413

Regenerative sorption compressors for cryogenic refrigeration  

NASA Technical Reports Server (NTRS)

Dramatic efficiency improvements for sorption coolers appear possible with use of compressor heat regeneration techniques. The general theory of sorption compressor heat regeneration is discussed in this paper, and several design concepts are presented. These designs result in long-life, low-vibration cryocoolers that potentially have efficiencies comparable to Stirling refrigerators for 65 to 90 K spacecraft instrument cooling applications.

Bard, Steven; Jones, Jack A.

1990-01-01

414

Air Conditioning and Refrigeration. Book Two.  

ERIC Educational Resources Information Center

This curriculum guide (book II), along with book I, is designed to provide students with the basic skills for an occupation in air conditioning and refrigeration. Six major areas are included, each consisting of one or more units of instruction. These areas and their respective units are titled as follows: Electricity (fundamentals of electricity,…

Wantiez, Gary W.

415

Air Conditioning and Refrigeration Supplementary Units.  

ERIC Educational Resources Information Center

This document contains supplemental materials for special needs high school students intended to facilitate their mainstreaming in regular air conditioning and refrigeration courses. Teacher's materials precede the materials for students and include general notes for the instructor, additional suggestions, two references, a questionnaire on the…

Winston, Del; And Others

416

Readings in Air Conditioning and Refrigeration.  

ERIC Educational Resources Information Center

Designed to encourage vocational high school students to read by offering reading materials relevant to their vocational goals, this document contains thirty-seven articles related to air conditioning and refrigeration which have been selected from trade journals, magazines, and newspapers and adapted to the students' reading capabilities. A…

Uberto, Jeffrey A.

417

Lead acid batteries in solar refrigeration systems  

Microsoft Academic Search

Batteries play a vital role in solar photovoltaic refrigeration systems. Despite breakthroughs in operational characteristics of various components of such systems, lead acid batteries continue to be the only viable electrical energy storage devices as of date. The purpose of this paper is to report the results of characterization of a lead acid battery system as a component of a

Thomachan A Kattakayam; K Srinivasan

2004-01-01

418

A pulse tube refrigerator below 2 K  

Microsoft Academic Search

Up to now, all pulse tube refrigerators operating at the liquid helium temperature range use 4He as the working fluid. However, the lambda transition of 4He is a barrier for reaching temperatures below 2 K. Theoretical analysis in this paper shows that, using 3He, the temperature limit is below 2 K, and the efficiency of a 4 K pulse tube

M. Y. Xu; Y. L. Ju

1999-01-01

419

Ground Loops for Heat Pumps and Refrigeration  

E-print Network

Ground loops are used for water source heat pumps. Refrigeration can be put on a ground loop. Water-cooled condensing units are more efficient than air-cooled, and they can be put indoors. Indoor location makes piping for desuperheater hot water...

Braud, H. J.

1986-01-01

420

Air Conditioning and Refrigeration Book III.  

ERIC Educational Resources Information Center

Designed to present theory as a functional aspect, this air conditioning and refrigeration curriculum guide is comprised of nine units of instruction. Unit titles include (1) Job Orientation, (2) Applying for a Job, (3) Customer Relations, (4) Business Management, (5) Psychometrics, (6) Residential Heat Loss and Heat Gain, (7) Duct Design and…

Eckes, William; Fulkerson, Dan

421

Advanced insulations for refrigerated shipping containers  

Microsoft Academic Search

This article reports on a research project that was recently conducted to find a cost effective insulation for refrigerated shipping containers (reefers) that avoids the environmental problems associated with CFCs currently used in foam insulated reefers. Advanced vacuum insulations (which contain no CFCs and have high thermal resistances) have been studied at U.S. National Laboratories and at several companies in

K. T. Jr

1993-01-01

422

Fuzzy Technology in the Refrigeration & Airconditioning Systems  

NASA Astrophysics Data System (ADS)

Recently, in many goods, new products applied by Fuzzy theory are produced. In the refrigeration & airconditioning systems, I discussed in this paper (1) the application methods (2) the technic problems (3) key-technology. Specially, I discussed (1) physical mechanism & Fuzzy (2) tuning tools (3) self organiging functions.

Matsuoka, Fumio

423

Refrigerated display case lighting with LEDs  

NASA Astrophysics Data System (ADS)

The rapid development of high brightness light emitting diodes (LEDs) has triggered many applications, especially in the area of display lighting. This paper focuses on the application of white LEDs in refrigerated display cases. The fluorescent lighting presently used in commercial refrigerators is inefficient in the application and also it provides poor lighting for merchandising. A laboratory human factors experiment was conducted to assess the preference for the different lighting systems, namely, fluorescent and LED. Two refrigerated display cases, one with the traditional fluorescent lighting system and the other with a prototype LED lighting system, were placed side-by-side in a laboratory setting. Illuminance measurements made within the two display cases showed that the lighting was more uniform with the LED system compared to the traditional fluorescent system. Sixteen human subjects participated in this study and rated their preference for the two lighting systems. The results show that human subjects strongly preferred the display case with the LED lighting. The authors of this manuscript believe a field study would be greatly beneficial to further confirm these results and to understand the relationship between preference and sales. Considering the luminous efficacy of white LEDs presently available in the marketplace, it is possible to develop a LED based lighting system for commercial refrigerators that is competitive with fluorescent lighting system in terms of energy use. The LED based lighting would provide better lighting than traditional fluorescent lighting.

Raghavan, Ramesh; Narendran, Nadarajah

2002-11-01

424

Metrics for Air Conditioning & Refrigeration, Heating, Ventilating.  

ERIC Educational Resources Information Center

Designed to meet the job-related metric measurement needs of the air conditioning and refrigeration, heating and ventilating student, this instructional package is one of three for the construction occupations cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already…

Cooper, Gloria S., Ed.; Magisos, Joel H., Ed.

425

Numerical Simulation of Refrigerated Display Cabinets  

Microsoft Academic Search

Food requires strict temperature control throughout the so-called 'cold-China', in which a particular storage temperature is need for each link. Display cabinets are known to be the weakest link from this point of view and, therefore, particular attention is paid to their design. And it is a real challenge for manufacturers and users of refrigerated display cabinets to provide the

Yan-li Lv; Wen-hui Zhang; Yi Gong; Wen-quan Tao

2007-01-01

426

Cooling by heating: refrigeration powered by photons.  

PubMed

We propose a new mechanism for refrigeration powered by photons. We identify the strong coupling regime for which maximum efficiency is achieved. In this case, the cooling flux is proportional to T in the low temperature limit T?0. PMID:22540566

Cleuren, B; Rutten, B; Van den Broeck, C

2012-03-23

427

The smallest refrigerators can reach maximal efficiency  

E-print Network

We investigate whether size imposes a fundamental constraint on the efficiency of small thermal machines. We analyse in detail a model of a small self-contained refrigerator consisting of three qubits. We show analytically that this system can reach the Carnot efficiency, thus demonstrating that there exists no complementarity between size and efficiency.

Paul Skrzypczyk; Nicolas Brunner; Noah Linden; Sandu Popescu

2010-09-04

428

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

Microsoft Academic Search

This study examined the growth characteristics of Listeria 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, consisting of Brochothrix spp., isolated from cooked meat were inoculated alone (monocultured) or co-inoculated (co-cultured) onto cooked ham slices. The growth characteristics, lag phase duration (LPD, h),

Cheng-An Hwang; Shiowshuh Sheen

2011-01-01

429

Modeling of Solar-Powered Single-Effect Absorption Cooling System and Supermarket Refrigeration\\/HVAC System  

Microsoft Academic Search

This thesis consists of two different research problems. In the first one, the aim is to model and simulate a solar-powered, single-effect, absorption refrigeration system using a flat-plate solar collector and LiBr-H2O mixture as the working fluid. The cooling capacity and the coefficient of performance of the system are analyzed by varying all independent parameters, namely: evaporator pressure, condenser pressure,

Ammar Bahman

2011-01-01

430

Health effects among refrigeration repair workers exposed to fluorocarbons.  

PubMed Central

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

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

1986-01-01

431

Dilution cycle control for an absorption refrigeration system  

DOEpatents

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

Reimann, Robert C. (Lafayette, NY)

1984-01-01

432

The production of W-0.35HfC (Mol %) wirebar by arc melting and high energy rate extrusion of small diameter ingots  

NASA Astrophysics Data System (ADS)

Tungsten alloy fiber reinforced tungsten is a candidate emitter material for space nuclear thermionic multi-kilowatt power systems. Fuel swelling which results in emitter deformation has been a primary concern for being able to achieve long lived (7 years or greater) thermionic fuel elements (TFE) operating at temperatures at or above 1900 K. The tungsten alloy (W-0.35 mo/%HfC) has extremely attractive mechanical properties above 1900 K and is a candidate reinforcement of tungsten for emitters. Because of its high strength, processing of the W-035HfC alloy to small diameter (0.38mm) wire has been difficult and the yield of useable product has been low. The purpose of this work was to demonstrate that by vacuum arc melting 38mm diameter ingots and high energy rate extrusions, small diameter (18mm) rod could be produced which is more compatible with swaging equipment used in tungsten wire production. Six 38 mm diameter ingots of W-0.35 HfC were produced by consumable electrode vacuum arc melting. The ingots were clad in 46 mm diameter molybdenum heated to 2270K and successfully extruded through a zirconia coated die at a reduction ratio of 7:1. The microstructure of the as-extruded bars is highly worked and should be amenable to processing to small diameter wire.

Buckman, R. William; Begg, Lester L.

1991-01-01

433

The production of W-0. 35HfC (Mol %) wirebar by arc melting and high energy rate extrusion of small diameter ingots  

SciTech Connect

Tungsten alloy fiber reinforced tungsten is a candidate emitter material for space nuclear thermionic multi-kilowatt power systems. Fuel swelling which results in emitter deformation has been a primary concern for being able to achieve long lived (7 years or greater) thermionic fuel elements (TFE) operating at temperatures at or above 1900 K. The tungsten alloy (W-0.35 mo/%HfC) has extremely attractive mechanical properties above 1900 K and is a candidate reinforcement of tungsten for emitters. Because of its high strength, processing of the W-035HfC alloy to small diameter (0.38mm) wire has been difficult and the yield of useable product has been low. The purpose of this work was to demonstrate that by vacuum arc melting 38mm diameter ingots and high energy rate extrusions, small diameter (18mm) rod could be produced which is more compatible with swaging equipment used in tungsten wire production. Six 38 mm diameter ingots of W-0.35 HfC were produced by consumable electrode vacuum arc melting. The ingots were clad in 46 mm diameter molybdenum heated to 2270K and successfully extruded through a zirconia coated die at a reduction ratio of 7:1. The microstructure of the as-extruded bars is highly worked and should be amenable to processing to small diameter wire.

Buckman, R.W. Jr. (Westinghouse Electric Corp. Advanced Energy Systems P.O. Box 10864 Pittsburgh, PA 15236 (USA)); Begg, L.L. (General Atomics P. O. Box 85608 San Diego, CA 92186-9784 (USA))

1991-01-01

434

Binary mixed-refrigerants for steady cooling temperatures between 80 K and 150 K with Joule-Thomson cryocoolers  

NASA Astrophysics Data System (ADS)

Joule-Thomson (JT) cryocoolers operating with pure gases attain vapor-liquid equilibrium in the evaporator and yield a steady cooling temperature which depends solely on the pressure. Mixed gases often substitute the pure gases as the working fluid in order to allow lower pressure ratios and improved coefficient of performance; however, mixed refrigerants are known for their cooling temperature dependence on the ambient temperature and heat load. It is possible to control the cooling temperature via the compressor operating parameters, heating device at the evaporator, bypass ports for the fluid, and more. The present research aims to achieve a steady cooling temperature with mixed refrigerants in a manner similar to pure refrigerants; meaning, having enough phases to leave a single degree of freedom of the fluid thermodynamic state. Thus, by stabilizing the pressure a stable temperature is attained. The current study focuses on binary mixtures since they can be analytically investigated in a more convenient manner relative to multi-component mixtures. Nitrogen-ethane and nitrogen-propane mixtures are considered based on former research conclusions. The present research includes an analytical method for calculating the cooling temperature, a numerical method for calculating the cooling power of the JT cryocooler in order to evaluate whether the cooling temperature is feasible, and experimental data are presented to verify some of the calculated results.

Tzabar, N.

2014-11-01

435

IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems  

SciTech Connect

With increased concern about the impact of refrigerant leakage on global warming, a number of new supermarket refrigeration system configurations requiring significantly less refrigerant charge are being considered. In order to help promote the development of advanced systems and expand the knowledge base for energy-efficient supermarket technology, the International Energy Agency (IEA) established IEA Annex 26 (Advanced Supermarket Refrigeration/Heat Recovery Systems) under the ''IEA Implementing Agreement on Heat Pumping Technologies''. Annex 26 focuses on demonstrating and documenting the energy saving and environmental benefits of advanced systems design for food refrigeration and space heating and cooling for supermarkets. Advanced in this context means systems that use less energy, require less refrigerant and produce lower refrigerant emissions. Stated another way, the goal is to identify supermarket refrigeration and HVAC technology options that reduce the total equivalent warming impact (TEWI) of supermarkets by reducing both system energy use (increasing efficiency) and reducing total refrigerant charge. The Annex has five participating countries: Canada, Denmark, Sweden, the United Kingdom, and the United States. The working program of the Annex has involved analytical and experimental investigation of several candidate system design approaches to determine their potential to reduce refrigerant usage and energy consumption. Advanced refrigeration system types investigated include the following: distributed compressor systems--small parallel compressor racks are located in close proximity to the food display cases they serve thus significantly shortening the connecting refrigerant line lengths; secondary loop systems--one or more central chillers are used to refrigerate a secondary coolant (e.g. brine, ice slurry, or CO2) that is pumped to the food display cases on the sales floor; self-contained display cases--each food display case has its own refrigeration unit; low-charge direct expansion--similar to conventional multiplex refrigeration systems but with improved controls to limit charge. Means to integrate store HVAC systems for space heating/cooling with the refrigeration system have been investigated as well. One approach is to use heat pumps to recover refrigeration waste heat and raise it to a sufficient level to provide for store heating needs. Another involves use of combined heating and power (CHP) or combined cooling, heating, and power (CCHP) systems to integrate the refrigeration, HVAC, and power services in stores. Other methods including direct recovery of refrigeration reject heat for space and water heating have also been examined.

Baxter, VAN

2003-05-19

436

Element, Mixture, Compound  

NSDL National Science Digital Library

Students gain a better understanding of the different types of materials as pure substances and mixtures and learn to distinguish between homogeneous and heterogeneous mixtures by discussing an assortment of example materials they use and encounter in their daily lives.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

437

The Mixtures Lab  

NSDL National Science Digital Library

The representation illustrates the separation of mixtures using physical properties. The interactive simulation allows "lab attendants" to separate mixtures using virtual tools. Separation mechanisms are chosen based upon substances' physical properties, and findings are recorded in a chart.

438

Learning Mixtures of Gaussians  

Microsoft Academic Search

Mixtures of Gaussians are among the most fundamental and widely used statistical models. Current techniques for learning such mixtures from data are local search heuris- tics withweak performance guarantees. We present the first provably correct algorithm for learning a mixture of Gaus- sians. This algorithm is very simple and returns the true centers of the Gaussians to withinthe precision specified

Sanjoy Dasgupta

1999-01-01

439

10 CFR 431.64 - Uniform test method for the measurement of energy consumption of commercial refrigerators...  

Code of Federal Regulations, 2013 CFR

...for the measurement of energy consumption of commercial refrigerators, freezers, and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2013-01-01

440

10 CFR 431.64 - Uniform test method for the measurement of energy consumption of commercial refrigerators...  

Code of Federal Regulations, 2012 CFR

...for the measurement of energy consumption of commercial refrigerators, freezers, and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2012-01-01

441

10 CFR 431.64 - Uniform test method for the measurement of energy consumption of commercial refrigerators...  

Code of Federal Regulations, 2011 CFR

...for the measurement of energy consumption of commercial refrigerators, freezers, and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2011-01-01

442

10 CFR 431.64 - Uniform test method for the measurement of energy consumption of commercial refrigerators...  

Code of Federal Regulations, 2010 CFR

...for the measurement of energy consumption of commercial refrigerators, freezers, and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2010-01-01

443

10 CFR 431.64 - Uniform test method for the measurement of energy consumption of commercial refrigerators...  

...for the measurement of energy consumption of commercial refrigerators, freezers, and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2014-01-01

444

Compact Claude cycle refrigerator for laboratory use  

NASA Technical Reports Server (NTRS)

A Claude cycle refrigerator with a three stage reciprocating expansion engine is described. Instead of a cam mechanism, valves are driven directly by magnetic solenoids operated by means of a micro processor control system. A swash plate mechanism is used to convert reciprocating motion of the expander pistons to rotary motion. A refrigeration capacity of 8 watts was achieved at 4.5 K with the operating pressure of 1.1 MPa and flow rate of 2.4 g/sec.. An effect of overintake operation was studied. Experimental results show that the efficiency of the expander has a peak point in the region of overintake operation with constant cycle speed, which agrees with theoretical results. The electrically controlled valve system is useful to vary the valve timing to achieve an optimum condition of operation.

Hiersaki, Y.; Kaneko, M.; Munekata, T.; Baba, Y.; Matsubara, Y.; Yasukochi, K.

1983-01-01

445

Economical Analysis about Ammonia Absorption Refrigeration Plants  

NASA Astrophysics Data System (ADS)

NH3-H2O absorption refrigeration plant is attractive from each standpoint of electric power saving, non-fluorocarbon and energy saving. The plant can be the economic alternative of power compression refrigeration for evaporation temperature range from 0°C to -60°C, using suitable waste heat (co-generation system, waste incinerator), oil and natural gas. In the application of the plant, the equipment cost and the COP must be reasonable from economical standpoint. Therefore, the paper shows the following. 1) Necessary heating temparature analysis for absorption plant 2) Equipment cost analysis for heating temperature 3) Equipment cost analysis for COP 4) Number of trays in the rectifying column for COP 5) Equipment cost analysis and COP in two-stage absorption

Takei, Toshitaka

446

Screw Compressor Characteristics for Helium Refrigeration Systems  

NASA Astrophysics Data System (ADS)

The oil injected screw compressors have practically replaced all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, minimal vibration, reliability and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium systems, typically two-thirds of the lost input power is due to the compression system. Therefore it is important to understand the isothermal and volumetric efficiencies of these machines to help properly design these compression systems to match the refrigeration process. This presentation summarizes separate tests that have been conducted on Sullair compressors at the Superconducting Super-Collider Laboratory (SSCL) in 1993, Howden compressors at Jefferson Lab (JLab) in 2006 and Howden compressors at the Spallation Neutron Source (SNS) in 2006. This work is part of an ongoing study at JLab to understand the theoretical basis for these efficiencies and their loss mechanisms, as well as to implement practical solutions.

Ganni, V.; Knudsen, P.; Creel, J.; Arenius, D.; Casagrande, F.; Howell, M.

2008-03-01

447

An electrocaloric refrigerator without external regenerator  

NASA Astrophysics Data System (ADS)

Regeneration processes are commonly used in cooling devices to improve the device performance. However, irreversible heat loss within the regenerators in many earlier designs of magnetocaloric and electrocaloric (EC) based cooling devices reduces the device performance. In this paper, an electrocaloric based refrigerator without external regenerators is proposed and studied. The regeneration process in this device is realized by direct heat exchange between contacting EC elements which are moving in opposite directions with different applied fields. Simulation results show that a 37 W/cm3 cooling power density is obtained for a Tspan of 20 K while the refrigerator still maintains 57% of Carnot efficiency for a cooling device made of an EC polymer.

Gu, Haiming; Qian, Xiao-Shi; Ye, Hui-Jian; Zhang, Q. M.

2014-10-01

448

Theory of an active magnetic regenerative refrigerator  

SciTech Connect

The adiabatic temperature change with field is limited to about 2 K/Tesla for ferromagnets near their Curie temperatures by the change of magnetization with temperature and the lattice heat capacity. Hence, practical magnetic refrigerators operate on a regenerative cycle such as the Brayton cycle. One way to execute this cycle is through the use of an active magnetic regenerator, i.e. a regenerator composed of magnetic material that is cycled in an out of a magnetic field with appropriate fluid flows. The theory of these devices can be predicted by solving the partial differential equations that describe fluid and the magnetic solid. The active magnetic regenerator is described along with the method of calculation. Temperature profiles for a normal regenerator and a magnetic regenerative refrigerator are shown.

Barclay, J.A.

1982-01-01

449

Two design aspects of defrosting refrigerators  

Microsoft Academic Search

This paper shows that the intermittent operation of a defrosting vapour-compression-cycle refrigerator can be optimized with respect to: (1) the frequency of on\\/off operation, and (2) the way in which the supply of heat exchanger surface is divided between evaporator and condenser. The method used is that of thermodynamic optimization (or entropy generation minimization, or finite-time thermodynamics), in which heat

J. S Lim

1995-01-01

450

Absorption refrigeration and heat pump system  

SciTech Connect

An absorption refrigeration and/or heating system in connection with a primary source of heat, a cooling or heating load, and a heat sink or secondary source, and an external source of mechanical energy to selectively provide heat to or remove heat from the load is described comprising: (a) a multiple effect generator means to apply the primary source of heat to an absorption solution pair comprising a highly volatile refrigerant, and an absorbent, and to desorb refrigerant from the pair; (b) first and second heat exchanger means, one of which is in heat exchange relationship with the heat sink or secondary source, and the other of which is in heat exchange relationship with the load, (c) valve means to selectively switch and reverse the functions of the first and second heat exchangers, from condenser to evaporator, in the cooling or heating mode and vice versa; (d) an absorber means selectively connectable to the first or second heat exchanger when the heat exchanger is functioning as the evaporator; (e) a pump means connected between the absorber means and the generator means to transfer solution flow to the generator means at higher pressure; (f) the generator means comprising coiled tubes with the coils juxtaposed one to the next in a generally annular composite form with a generator means surrounding the source of heat; (g) the pump means having connection means to mechanically convert pressure energy in the refrigerant and/or solution pair to mechanical energy, and means to add the converted mechanical energy to the mechanical energy externally supplied to the system; and (h) means to defrost the system.

Reid, E.A. Jr.; Cook, F.B.; Winter, E.M.; Merrick, R.H.; Purvis, E.M. Jr.; Cremean, S.P.

1988-01-19

451

Optimum temperature staging of cryogenic refrigeration system  

NASA Astrophysics Data System (ADS)

Optimum temperature staging is investigated to minimize entropy generation in a multi-stage cryogenic refrigeration cycle. It is found that the best intermediate temperature distribution is to have the same high to low temperature ratio at each stage of the system. As an example, the result is applied to the design of a cryogenic cascade thermoelectric cooler to find the optimum size distribution of each stage.

Jeong, S.; Smith, J. L.

452

Hydrocarbon Refrigerants for Car Air Conditioners  

Microsoft Academic Search

The world needs car air conditioning and the hydrocarbon (HC) refrigerant 290\\/600a avoids stratospheric ozone depletion and a typical 15% increase in TEWI from R134a leakage and service emissions. Measurements suggest that R290\\/600a (55\\/45) matches the performance of R134a best if ethane impurity is below 0.5%. Batches of HC replacement for R12, 134a, 22 and 502 can be manufactured from

Ian Maclaine-cross; E. Leonardi

453

Thermoelectric power generation in a thermoacoustic refrigerator  

Microsoft Academic Search

Commercially available solid-state thermoelectric devices may be used for their electrical power generation capabilities when coupled to a thermoacoustic refrigerator or heat pump. General performance characteristics as well as bulk thermal conductivity for a selection of thermoelectric elements was first found by using a two-plate apparatus to maintain a constant temperature difference across the element. Further studies of an element’s

W. V. Slaton; J. C. H. Zeegers

2006-01-01

454

Device applications of cryogenic optical refrigeration  

NASA Astrophysics Data System (ADS)

With the coldest solid-state temperatures (?T <185K from 300K) achievable by optical refrigeration, it is now timely to apply this technology to cryogenic devices. Along with thermal management and pump absorption, this work addresses the most key engineering challenge of transferring cooling power to the payload while efficiently rejecting optical waste-heat fluorescence. We discuss our optimized design of such a thermal link, which shows excellent performance in optical rejection and thermal properties.

Melgaard, Seth D.; Seletskiy, Denis V.; Epstein, Richard I.; Alden, Jay V.; Sheik-Bahae, Mansoor

2014-02-01

455

Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant  

Microsoft Academic Search

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor

John S. Hsu; Curtis W. Ayers; Chester Coomer; Laura D. Marlino

2006-01-01

456

Stirling cycle engine and refrigeration systems  

NASA Technical Reports Server (NTRS)

A Stirling cycle heat engine is disclosed in which displacer motion is controlled as a function of the working fluid pressure P sub 1 and a substantially constant pressure P sub 0. The heat engine includes an auxiliary chamber at the constant pressure P sub 0. An end surface of a displacer piston is disposed in the auxiliary chamber. During the compression portion of the engine cycle when P sub 1 rises above P sub 0 the displacer forces the working fluid to pass from the cold chamber to the hot chamber of the engine. During the expansion portion of the engine cycle the heated working fluid in the hot chamber does work by pushing down on the engine's drive piston. As the working fluid pressure P sub 1 drops below P sub 0 the displacer forces most of the working fluid in the hot chamber to pass through the regenerator to the cold chamber. The engine is easily combinable with a refrigeration section to provide a refrigeration system in which the engine's single drive piston serves both the engine and the refrigeration section.

Higa, W. H. (inventor)

1976-01-01

457

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

...1The amount of noncondensable gases shall be determined by gas chromatography. A sample of vaporized refrigerant liquid shall be separated and analyzed by gas chromatography. A Porapak Q column at 130 °C (266 °F) and a hot wire...

2014-07-01

458

Absorption refrigeration system for mobile applications utilizing exhaust gases  

NASA Astrophysics Data System (ADS)

A breadboard prototype of an absorption system for truck refrigeration using heat from the exhaust-gases was designed, built and tested. Measured COP values of the unoptimized single-stage ammonia-water absorption cycle varied between 23 and 30%, but system modeling shows that this can be improved to values considerably over 30%. Computer simulation for the system included cycle analysis as well as component modeling, using a detailed two-fluid model for flow of the ammonia-water mixture in the condenser and absorber. This detailed model was also validated using test data. In addition, the recoverable energy of the exhaust gases was analyzed for representative truck-driving conditions for city traffic, mountain roads and flat roads. The results show that the system is promising for long distance driving on flat roads. Zusammenfassung Es wurde ein Prototyp einer abgasbetriebenen Absorptionskälteanlage für Transportkühlung ausgelegt, gebaut und getestet. Das gemessene Wärmeverhältnis der noch nicht optimierten einstufigen Ammoniak-Wasser Absorptionskältemaschine (AKM) liegt zwischen 23 und 30%. Simulationsrechnungen zeigen, daß das Wärmeverhältnis auf deutlich über 30% gesteigert werden kann. Die Simulationsrechnungen wurden sowohl für den gesamten Kreisprozeß als auch für einzelne Komponenten durchgeführt. Insbesondere wurde für den Verflüssiger und Absorber ein detailiertes Zweifluidmodell für die Strömung des Ammoniak-Wasser-Gemisches entwickelt und mit Hilfe der Meßdaten validiert. Zusätzlich wurde für repräsentative Lkw Fahrten im Stadtverkehr und auf gebirgigen und ebenen Außerortsstrecken die nutzbare Abgasenergie analysiert. Die Ergebnisse zeigen, daß eine abgasbetriebene AKM besonders für Langstreckenfahrten auf ebener Strecke geeignet ist.

Koehler, J.; Tegethoff, W. J.; Westphalen, D.; Sonnekalb, M.

459

Development of a high efficiency, automatic defrosting refrigerator-freezer  

NASA Astrophysics Data System (ADS)

The development of an energy efficient refrigerator freezer prototype to accelerate the commercialization of residential, high efficiency refrigerator freezers is described. A computer model developed to simulate the cabinet and refrigeration unit performance was used to evaluate alternative designs and optimize the cabinet insulation as well as the refrigeration component integration. Placement of polyurethane foam insulation in the cabinet and thicker insulation in the doors were used to reduce the closed door heat load of the prototype. Modifications to the evaporator system provide automatic frost-free operation with a significantly reduced defrost energy requirement. Resulting higher moisture levels in the refrigerator compartment enhance fresh food storage. A dual control system, different from most models which use only one active control, provides precise temperature regulation in both the freezer and refrigerator compartments.

Topping, R. F.; Lee, W. D.

460

Magnetically suspended Stirling cryogenic space refrigerator Status report  

NASA Technical Reports Server (NTRS)

At the 1979 Cryogenic Engineering Conference, attention was given to conceptual designs of spaceborne cryogenic refrigeration systems which can provide long-term, unattended operation. Since that time, efforts have continued to translate one of those concepts into an engineering model. The present investigation is concerned with a refrigerator which was designed to generate 5 W of cooling power at a temperature of 65 K. The compression heat of the refrigerator is dissipated at a temperature of 300 K, and the output of the system is to be maintained reliably for a period of five years or longer. The refrigerator design is based on the Stirling cycle, which has an ideal efficiency equal to that of the Carnot cycle. Attention is given to some background information concerning a cryogenic refrigerator, the design of the refrigerator components, and the development status. The magnetic bearings and the linear motors have been tested at the component level.

Daniels, A.; Gasser, M.; Sherman, A.

1982-01-01

461

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

SciTech Connect

BEETIT Project: Astronautics is developing an air conditioning system that relies on magnetic fields. Typical air conditioners use vapor compression to cool air. Vapor compression uses a liquid refrigerant to circulate within the air conditioner, absorb the heat, and pump the heat out into the external environment. Astronautics’ design uses a novel property of certain materials, called “magnetocaloric materials”, to achieve the same result as liquid refrigerants. These magnetocaloric materials essentially heat up when placed within a magnetic field and cool down when removed, effectively pumping heat out from a cooler to warmer environment. In addition, magnetic refrigeration uses no ozone-depleting gases and is safer to use than conventional air conditioners which are prone to leaks.

None

2010-09-01

462

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

DOEpatents

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

Gschneidner, Jr., Karl A. (Ames, IA); Pecharsky, Vitalij K. (Ames, IA)

1998-04-28

463

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

DOEpatents

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

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

1998-04-28

464

Microcomputer Software for Refrigerant Property and Cycle Analysis Calculations  

E-print Network

for each fluorocarbon refrigerant, represent curve fits to existing tabular property data. For both ammonia and the fluorocarbon refrigerants, the equations for the following four basic properties of refrigerants are used. - Liquid density as a... often involve approximations from graphical data or tedious single-,' or sometimes double-interpola tions from tabular data. To provide a fast, accurate, and convenient alternative to these cumbersome procedures, REFRIG has been designed...

Bierschenk, J. L.; Strohl, S. T.; Schmidt, P. S.

465

Refrigerated dynamic seal to 6.9 MPa (1000 psi)  

NASA Technical Reports Server (NTRS)

The self sealing, high shear flow passage approach which was extended to large pressure differences was studied. In a refrigerated seal the fluid to be sealed flows through a refrigerated housing or constriction. The fluid can be frozen to the housing during the transient phase. Under steady state conditions the refrigerated seal proves to be a dynamic low leakage seal. The concept is extended to pressure differences of 6.9 MPa.

Hendricks, Robert C.; Mullen, R. L.; Braun, M. J.

1986-01-01

466

Refrigerated dynamic seal to 6.9 MPa (1000 psi)  

NASA Technical Reports Server (NTRS)

The self sealing, high shear flow passage approach which was extended to large pressure differences was studied. In a refrigerated seal the fluid to be sealed flows through a refrigerated housing or constriction. The fluid can be frozen to the housing during the transient phase. Under steady state conditions the refrigerated seal proves to be a dynamic low leakage seal. The concept is extended to pressure differences of 6.9 MPa.

Hendricks, R. C.; Mullen, R. L.; Braun, M. J.

1985-01-01

467

Magnetic refrigeration for space applications: Report on a design study  

NASA Astrophysics Data System (ADS)

Results of a preliminary design study of magnetic refrigerators for space applications are summarized. Three items are discussed: (1) a design for a 5-W, 4 K to 20 K magnetic-wheel refrigerator; (2) a theoretical evaluation of a new device, called a regenerative-magnetic expander, that operates between 3.8 K and 20 K; and (3) an active magnetic regenerator that provides refrigeration at 4 K and expels heat at 200 K.

Barclay, J. A.; Steyert, W. A.

1980-02-01

468

Magnetic refrigeration for space applications: report on a design study  

SciTech Connect

Results of a preliminary design study of magnetic refrigerators for space applications are summarized. Three items are discussed: (1) a design for a 5-W, 4 K to 20 K magnetic-wheel refrigerator; (2) a theoretical evaluation of a new device, called a regenerative-magnetic expander, that operates between 3.8 K and 20 K; and (3) an active magnetic regenerator that provides refrigeration at 4 K and expels heat at 200 K.

Barclay, J.A.; Steyert, W.A.

1980-02-01

469

New Design of Neon Refrigerator for Hts Power Machines  

Microsoft Academic Search

In 2007, we developed a prototype refrigerator with a small turbo-expander to provide adequate cooling power (2 kW at 70 K) for HTS (High Temperature Superconductor) power machines. The reverse-Brayton cycle with neon gas as a working fluid was adopted in the refrigerator. The prototype refrigerator does not have enough COP (Coefficient of Performance) for practical HTS applications, and the

S. Yoshida; H. Hirai; A. Takaike; M. Hirokawa; Y. Aizawa; Y. Kamioka; H. Okamoto; H. Hayashi; Y. Shiohara

2010-01-01

470

Process Options for Nominal 2-K Helium Refrigeration System Designs  

SciTech Connect

Nominal 2-K helium refrigeration systems are frequently used for superconducting radio frequency and magnet string technologies used in accelerators. This paper examines the trade-offs and approximate performance of four basic types of processes used for the refrigeration of these technologies; direct vacuum pumping on a helium bath, direct vacuum pumping using full or partial refrigeration recovery, cold compression, and hybrid compression (i.e., a blend of cold and warm sub-atmospheric compression).

Peter Knudsen, Venkatarao Ganni

2012-07-01

471

Magnetic refrigeration—towards room-temperature applications  

Microsoft Academic Search

Modern society relies very much on readily available cooling. Magnetic refrigeration based on the magneto-caloric effect (MCE) has become a promising competitive technology for the conventional gas-compression\\/expansion technique in use today. Recently, there have been two breakthroughs in magnetic-refrigeration research: one is that American scientists demonstrated the world's first room-temperature, permanent-magnet, magnetic refrigerator; the other one is that we discovered

E. H. Brück; O. Tegus; X. W. Li; F. R. de Boer; K. H. J. Buschow

2003-01-01

472

A rotary magnetic refrigerator for superfluid helium production  

Microsoft Academic Search

A new rotary-magnetic refrigerator designed to obtain superfluid helium temperatures by executing a magnetic Carnot cycle is developed. A rotor containing 12 magnetic refrigerants (gadolinium-gallium-garnet) is immersed in liquid helium at 4.2 K and rotated at constant speed in a steady magnetic field distribution. Performance tests demonstrate that the new rotary refrigerator is capable of obtaining a temperature of 1.48

Y. Hakuraku; H. Ogata

1986-01-01

473

Self-actuating heat switches for redundant refrigeration systems  

NASA Technical Reports Server (NTRS)

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

Chan, Chung K. (inventor)

1988-01-01

474

Spacecraft-borne long life cryogenic refrigeration: Status and trends  

NASA Technical Reports Server (NTRS)

The status of cryogenic refrigerator development intended for, or possibly applicable to, long life spacecraft-borne application is reviewed. Based on these efforts, the general development trends are identified. Using currently projected technology needs, the various trends are compared and evaluated. The linear drive, non-contacting bearing Stirling cycle refrigerator concept appears to be the best current approach that will meet the technology projection requirements for spacecraft-borne cryogenic refrigerators. However, a multiply redundant set of lightweight, moderate life, moderate reliability Stirling cycle cryogenic refrigerators using high-speed linear drive and sliding contact bearings may possibly suffice.

Johnson, A. L.

1983-01-01

475

A rotary magnetic refrigerator for superfluid helium production  

NASA Astrophysics Data System (ADS)

A new rotary-magnetic refrigerator designed to obtain superfluid helium temperatures by executing a magnetic Carnot cycle is developed. A rotor containing 12 magnetic refrigerants (gadolinium-gallium-garnet) is immersed in liquid helium at 4.2 K and rotated at constant speed in a steady magnetic field distribution. Performance tests demonstrate that the new rotary refrigerator is capable of obtaining a temperature of 1.48 K. The maximum useful cooling power obtained at 1.8 K is 1.81 W which corresponds to a refrigeration efficiency of 34%.

Hakuraku, Y.; Ogata, H.

1986-11-01

476

7 CFR 3300.37 - Testing of a mechanical refrigerating appliance.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Testing of a mechanical refrigerating appliance. 3300... Procedures for Separate Testing of Mechanical Refrigerating Appliances § 3300.37 Testing of a mechanical refrigerating appliance. For...

2013-01-01

477

7 CFR 3300.37 - Testing of a mechanical refrigerating appliance.  

...2014-01-01 false Testing of a mechanical refrigerating appliance. 3300... Procedures for Separate Testing of Mechanical Refrigerating Appliances § 3300.37 Testing of a mechanical refrigerating appliance. For...

2014-01-01

478

76 FR 29791 - Bottom Mount Combination Refrigerator-Freezers From Korea and Mexico  

Federal Register 2010, 2011, 2012, 2013

...from Korea of bottom mount combination refrigerator-freezers...from Mexico of bottom mount combination refrigerator-freezers...consumer organizations have the right to appear as parties in Commission...subsidized imports of bottom mount combination refrigerator-freezers...

2011-05-23

479

7 CFR 3300.37 - Testing of a mechanical refrigerating appliance.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Testing of a mechanical refrigerating appliance. 3300... Procedures for Separate Testing of Mechanical Refrigerating Appliances § 3300.37 Testing of a mechanical refrigerating appliance. For...

2011-01-01

480

7 CFR 3300.37 - Testing of a mechanical refrigerating appliance.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Testing of a mechanical refrigerating appliance. 3300... Procedures for Separate Testing of Mechanical Refrigerating Appliances § 3300.37 Testing of a mechanical refrigerating appliance. For...

2012-01-01