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1

Surface tension of HFC refrigerant mixtures  

SciTech Connect

The surface tension of refrigerant mixtures, i.e., R-410A (50 mass% R-32/50 mass% R-125), R-410B (45 mass% R-32/55 mass% R-125), R-407C (23 mass% R-32/25 mass% R-125/52 mass% R-134a), R-404A (44 mass% R-125/52 mass% R-143a/4 mass% R-134a), and R-507 (50 mass% R-125/50 mass% R-143a), has been measured and correlated in the present study. Although the first three mixtures are very important as promising replacements for R-22 in air-conditioners and heat-pumps and the last two are promising replacements for R-502, surface tension data for these mixtures were not previously available. The measurements were conducted under conditions of coexistence of the sample liquid and its saturated vapor in equilibrium. The differential capillary rise method (DCRM) was used, with two glass capillaries with inner radii of 0.3034 {+-} 0.0002 and 0.5717 {+-} 0.0002 mm. The temperature range covered was from 273 to 323 K, and the uncertainty of measurements for surface tensions and temperatures is estimated to be at most {+-} 0.2 mN {center_dot} m{sup {minus}1} and {+-} 20 mK, respectively. A mixing rule was selected for representing the temperature dependence of the resultant data. These data were successfully represented by a mixing rule using mass fraction based on the van der Waals correlation.

Okada, M. [Tsukuba Coll. of Technology (Japan). Dept. of Mechanical Engineering; Shibata, T.; Sato, Y.; Higashi, Y. [Iwaki Meisei Univ. (Japan)

1999-01-01

2

TWO-PHASE FLOW OF TWO HFC REFRIGERANT MIXTURES THROUGH SHORT-TUBE ORIFICES  

EPA Science Inventory

The report gives results of an experimental investigation to develop an acceptable flow model for short tube orifice expansion devices used in heat pumps. The refrigerants investigated were two hydrofluorocarbon (HFC) mixtures considered hydrochlorofluorocarbon (HCFC)-22 replacem...

3

The surface tension of HFC refrigerants and mixtures  

Microsoft Academic Search

The surface tension of the refrigerants R32, R125, R134a, R143a and R152a, as well as the binary refrigerant mixtures R32-R125, R32-R134a, R125-R134a, R125-R143a, R125- R152a, R143a-R134a and R134a-R152a, and the commercially available ternary mixtures R404A and R407C was measured across the temperature range from ?50 to 60°C using a measuring unit based on the capillary rise method. Different formulations for

R Heide

1997-01-01

4

Performance evaluation of two azeotropic refrigerant mixtures of HFC134a with R-290 (propane) and R-600a (isobutane)  

Microsoft Academic Search

The reduction in chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) production and the scheduled phase-out of these ozone-depleting refrigerants require the development and determination of environmentally safe refrigerants for use in heat pumps, water chillers, air conditioners, and refrigerators. This paper presents a performance evaluation of a generic heat pump with two azeotropic refrigerant mixtures of HFC-134a (1,1,1,2-tetrachloroethane) with R-290 (propane) and

M. S. Kim; W. J. Mulroy; D. A. Didion

1994-01-01

5

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

6

Performance evaluation of two azeotropic refrigerant mixtures of HFC-134a with R-290 (propane) and R-600a (isobutane)  

SciTech Connect

The reduction in chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) production and the scheduled phase-out of these ozone-depleting refrigerants require the development and determination of environmentally safe refrigerants for use in heat pumps, water chillers, air conditioners, and refrigerators. This paper presents a performance evaluation of a generic heat pump with two azeotropic refrigerant mixtures of HFC-134a (1,1,1,2-tetrachloroethane) with R-290 (propane) and R-600a (isobutane); R-290/134a (45/55 by mass percentage) and R-134a/600a (80/20 by mass percentage). The performance characteristics of the azeotropes were compared with pure CFC-12, HFC-134a, HCFC-22, and R-290 at the high temperature cooling and heating conditions including those using liquid-line/suction-line heat exchange. The coefficient of performance of R-290/134a is lower than that of HCFC-22 and R-290, and R-134a/600a shows higher coefficient of performance than CFC-12 and HFC-134a. The capacity for R-290/134a is higher than that for HCFC-22 and R-290, and R-134a/600a exhibits higher system capacity than CFC-12 and HFC-134a. Experimental results show that the discharge temperatures of the studied azeotropic mixtures are lower than those of the pure refrigerants, CFC-12 and HCFC-22.

Kim, M.S.; Mulroy, W.J.; Didion, D.A. (National Inst. of Standards and Technology, Gaithersburg, MD (United States). Building and Fire Research Lab.)

1994-06-01

7

Pressure drop of pure hfc refrigerants and their mixtures flowing in capillary tubes  

Microsoft Academic Search

The pressure drop of a capillary tube flow is experimentally investigated. In this study, pure refrigerants such as R32, R125 and R134a and their mixtures such as R32\\/R134a (3070 by mass fraction), R32\\/R125 (6040), R125\\/R134a (3070) and R32\\/R125\\/R134a (23\\/25\\/52) are used as test fluids. The binary interaction parameters for viscosities of the liquid state of refrigerant mixtures are found based

S.-D. Chang; S. T. Ro

1996-01-01

8

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...

9

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

10

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...

11

Isothermal VLE measurements for the binary mixtures HFC134a + HFC245fa and HC600a + HFC245fa  

Microsoft Academic Search

The substitution of CFC-114 in high temperature heat pumps is still far from being solved. Some pure compounds such as 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) and 1,1,1,3,3-pentafluoropropane (HFC-245fa) have been proposed, but it is probable that the best alternative will be given by a binary or ternary mixture including one of these fluids. The experimental data on the thermodynamic properties of

S Bobbo; L Fedele; M Scattolini; R Camporese

2001-01-01

12

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

13

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

SciTech Connect

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

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

1993-06-01

14

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

SciTech Connect

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

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

1993-01-01

15

Computing all the azeotropes in refrigerant mixtures through equations of state  

Microsoft Academic Search

Azeotropic mixtures of fluorocarbon (FC) and hydro fluorocarbon (HFC) with hydrocarbons are gaining popularity as drop-in substitutes for CFCs and HCFCs. A method to compute all the azeotropes in a refrigerant mixture through the equation of state approach is described. The method allows prediction of all the azeotropes in a refrigerant mixture and is in close agreement with the experimental

Naveed Aslam; Aydin K. Sunol

2004-01-01

16

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

17

Simulation of vapor-compression refrigeration cycles using HFC134a and CFC12  

SciTech Connect

A performance comparison analysis of vapor-compression refrigeration systems using refrigerant HFC134a and CFC12 is presented. The analysis is based on computer simulation of actual cycles rather than the ideal cycles. The simulation models for HFC134a and CFC12 are developed on the basis of fluid properties and thermo-hydraulic characteristics obtained from available experimental data and/or correlations. Using the simulation model thus developed, system performance with HFC134a and CFC12 are examined. A comparison of the performance of HFC134a and CFC12 is presented using COP (and compressor power) as a criterion for the same cooling load. Results indicate that the COP for HFC134a is slightly (about 3%) lower than that for a CFC12 system. This means that the power requirement for a HFC134a system is slightly higher than that for CFC12 system for an identical cooling requirement. A comparison of these two systems from a thermodynamic point of view is also presented using exergy loss as a performance evaluation criterion. These results indicate that the HFC134a system is only slightly inferior to the CFC 12 systems due to a higher (about 3%) exergy loss with HFC134a.

Chen, Q. [Combustion Dynamics Ltd., Halifax, Nova Scotia (Canada); Prasad, R.C. [Univ. of New Brunswick, Saint John, New Brunswick (Canada). Dept. of Engineering

1999-05-01

18

Ideal-Gas Heat Capacities and Virial Coefficients of HFC Refrigerants  

Microsoft Academic Search

Thermodynamic properties of HFC (hydrofluorocarbon) compounds have been extensively studied with worldwide interest as alternative refrigerants. Both quality and quantity in the experimental data far exceed those for the CFC and HCFC refrigerants. These data now provide a great opportunity to examine the validity of theoretical models, and vice versa. Among them, the ideal-gas heat capacity Cp0 and virial coefficients

A. Yokozeki; H. Sato; K. Watanabe

1998-01-01

19

Solubility of HFC-134a refrigerant in glycol-type compounds: Effects of glycol structure. [1,1,1,2-tetrafluoroethane  

SciTech Connect

Environmental concerns have dictated the replacement of CFC-12 refrigerant with HFC-134a in air-conditioning (A/C) systems. Since polyglycols are synthetic compounds compatible with HFC-134a and considered as lubricants for the A/C compressor, interactions of HFC-134a with glycol-type compounds and thermodynamic properties of the solutions are important in designing an A/C system. In this work, the solubility of HFC-134a in four glycol-type compounds was measured at [minus]5 to 80 C and 90 to 960 kPa. HFC-134a had the greatest solubility in tetraethylene glycol dimethyl ether. HFC-134a was less soluble in hexylene glycol and tetraethylene glycol and least soluble in triethylene glycol. Mixtures of HFC-134a with TRIG or TGDE showed phase separation. Solubility data were used to calculate the activity coefficient of HFC-134a in glycol solutions. An equation of the form, ln[gamma][sub r] = (1 [minus] x[sub r])[A + Bx[sub r

Tseregounis, S.I.; Riley, M.J. (General Motors Research and Development Center, Warren, MI (United States). Fuels and Lubricants Dept.)

1994-04-01

20

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

NASA Astrophysics Data System (ADS)

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

Akasaka, Ryo

21

Performance investigation of capillary tubes for machine tool coolers retrofitted with HFC-407C refrigerant  

NASA Astrophysics Data System (ADS)

The machine tool coolers are the best managers of coolant temperature in avoiding the deviation of spindle centerline for machine tools. However, the machine coolers are facing the compressed schedule to phase out the HCFC (hydro-chloro-floro-carbon) refrigerant and little attention has been paid to comparative study on sizing capillary tube for retrofitted HFC (hydro-floro-carbon) refrigerant. In this paper, the adiabatic flow in capillary tube is analyzed and modeled for retrofitting of HFC-407C refrigerant in a machine tool cooler system. A computer code including determining the length of sub-cooled flow region and the two phase region of capillary tube is developed. Comparative study of HCFC-22 and HFC-407C in a capillary tube is derived and conducted to simplify the traditional trial-and-error method of predicting the length of capillary tubes. Besides, experimental investigation is carried out by field tests to verify the simulation model and cooling performance of the machine tool cooler system. The results from the experiments reveal that the numerical model provides an effective approach to determine the performance data of capillary tube specific for retrofitting a HFC-407C machine tool cooler. The developed machine tool cooler system is not only directly compatible with new HFC-407C refrigerant, but can also perform a cost-effective temperature control specific for industrial machines.

Wang, Fujen; Chang, Tongbou; Chiang, Weiming; Lee, Haochung

2012-09-01

22

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

23

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

EPA Science Inventory

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

24

A review of lubrication and preformance issues in refrigeration systems using an HFC (R-134a) refrigerant  

SciTech Connect

It has been considered critical for refrigerant and compressor lubricant to be miscible with each other over part of the range of operating conditions of refrigerant systems. Adequate miscibility, many believe, provides oil return to the compressor. Presently, synthetic polyol esters have been selected for use with HFC refrigerants, such as R-134a, which are considered appropriate alternatives to CFCs. The authors will review the mechanical issues in miscible vs non-miscible naphthenic hydrocarbon oil-based lubricants. Extensive lab, test stand and cabinet testing has been conducted and data will be presented which show responsible and predictable performance based on the chemical and physical properties of the lubricant and refrigerant. Many non-miscible systems show satisfactory performance with the proper selection of lubricant, additives and mechanical configuration. 3 refs., 3 figs., 5 tabs.

Reyes-Gavilan, J.; Eckard, A.; Flak, T.; Tritak, T. [Witco Corporation, Oakland, NJ (United States)

1996-04-01

25

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

26

Evaluation of ozone-friendly hydrofluoropropane-based zeotropic refrigerant mixtures in a Lorenz-Meutzner refrigerator/freezer  

SciTech Connect

In this study, the L-M R/F having two evaporators and two intercoolers was experimentally tested in an environmental chamber according to Association of Home Appliance Manufacturers/Department of Energy testing standards using several hydrofluoropropane-based zeotropic mixtures. The results are compared to baseline testing with HFC-134a. A refrigerant sampling loop was added to determine the running composition of the mixture and its effect on the R/F performance.

Baskin, E.; Bayoglu, E.; Delafield, F.R.

1995-01-01

27

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

28

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

29

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

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

2013-07-01

30

EVALUATION OF PERFORMANCE AND COMPOSITION SHIFT OF ZEOTROPIC MIXTURES IN A LORENZ-MEUTZNER REFRIGERATOR/FREEZER  

EPA Science Inventory

Results from previous testing of this refrigerator/freezer (R/F) using a 750 Btu/hr compressor and several zeotrophic mixtures revealed a performance enhancement up to 16 percent above that of HFC-134a. In the study presented in this paper, the Lorenz-Meutzner (LM) R/F equipped ...

31

Consideration of Sludge Formation in HFC-134a / Polyol Ester oil Refrigeration System  

NASA Astrophysics Data System (ADS)

A refrigeration test employing HFC-134a and polyol ester oil was carried out in order to make clear the causes of the sludge formation in the capillary tube. Compressors used were two types: a hermetic reciprocating compressor and a rotary compressor. Installed dryer contained desiccant of the compound zeolite type. The results showed that the amount of capillary sludge increased as the compressor temperature rose. The capillary sludge was determined to consist of desiccant and metal dust for the reciprocating compressor, and of tar-like substance for the rotary compressor. Thermal stability test which was used to check the degree of deterioration of the ester oil, suggested that the presence of desiccant and high compressor temperature might produce tar-like substance by the break down and polymerization of the ester oil. In addition, it was confirmed that factors affecting the sludge formation were the dirtiness of the refrigeration circuit for the reciprocating compressor, and the presence of desiccant, for the rotary compressor.

Yamamoto, Tsutomu; Yamamoto, Tethuya; Simizu, Yasuhiko; Nakayama, Yoshinori; Takizawa, Kikuo

32

PERFORMANCE OF A TWO-CYCLE REFRIGERATOR/FREEZER USING HFC REFRIGERANTS  

EPA Science Inventory

A two-cycle 18 ft3 (0.51 m3) refrigerator/freezer (R/F) was tested utilizing American National Standards Institute (ANSI)/AHAM (1988) standards for energy consumption testing. A 34.9% energy consumption reduction was realized. This work presents a proven method of reducing the ...

33

Vaper Pressures for Mixtures of HFC-134a and Polyalkylene-glycol Oil  

NASA Astrophysics Data System (ADS)

This paper reports experimental results of the vapor pressure for mixtures of HFC-134a and polyalkylene-glycol(PAG) oil. The vapor pressure has been measured for temperatures from 283.15 K to 333.15 K and pressures up to 1.68 MPa. The mass fraction of HFC-134a in liquid phase ranges from 0.1 to 1 HFC-134a. The uncertainty of the measurements is estimated as ±15mK in temperature, ±8kPa in pressure and ±1% in concentration, respectively. The correlation equation that interpolates the experimental vapor pressures as a function of temperature and concentration is also presented for practical use.

Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

34

Heat exchanger analysis for nonazeotropic refrigerant mixtures  

SciTech Connect

A fundamental method for analyzing heat exchangers using pure refrigerants and nonazeotropic refrigerant mixtures is presented. The method allows for calculation of heat and mass transfer between moist air and nonazeotropic refrigerant mixtures and predicts local parameters of air and mixtures. Both single and two phase refrigerants can be analyzed with this method. Algorithms for the use of this model are presented. Data and calculated thermal performance for two conventional types of air-side geometries are also presented. The algorithms to calculate thermal performance of heat exchangers can be used for either conventional or enhanced geometries. A comparison of crossflow, cross-counterflow, and counterflow heat exchangers is given. The algorithms are sufficient for design and development of equipment using pure and mixed refrigerants.

Poz, M.Y. [Russian Association of Engineers for Heating, Ventilation, Air Conditioning, Heat Supply and Building Thermal Physics (ABOK), Moscow (Russian Federation); Conklin, J.C. [Oak Ridge National Lab., TN (United States)

1994-02-01

35

A Prediction Method of Local Heat and Mass Transfer Characteristics of Multi-component Zeotropic Refrigerant Mixture Condensing in A Horizontal Smooth Tube  

NASA Astrophysics Data System (ADS)

This paper deals with a prediction method for the condensation of a multi-component refrigerant mixture inside a horizontal smooth tube. The present method is obtained by extending our prediction method for a binary zeotropic refrigerant mixture to multi-component one. The governing equations for the local heat and mass transfer characteristics are derived based on the some reliable assumptions such as the phase equilibrium is established only at the vapor-liquid interface. In order to demonstrate the present method, the local heat and mass transfer characteristics of ternary zeotropic refrigerant mixtures composed of HFC32/HFC125/HFC134a, including R407C, are evaluated for a counterflow double-tube condenser cooed by water. Then, the local values of vapor quality, thermodynamic states at bulk vapor, vapor-liquid interface and bulk liquid, heat flux and condensation mass flux are obtained. The effects of the composition of HFC32/HFC125/HFC134a on the total pressure drop and the heat transfer characteristics are also examined.

Koyama, Shigeru; Lee, Sang-Mu

36

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

Microsoft Academic Search

The Peng-Robinson equation of state with the van der Waals mixing rules was used to correlate vapor–liquid equilibrium (VLE)\\u000a data for HFC\\/HC, HFC\\/HFC, and HC\\/HC binary mixtures. The interaction parameter k\\u000a \\u000a ij\\u000a was obtained for every binary mixture. It was assumed that k\\u000a \\u000a ij\\u000a has contributions from the two components, and each component has its own constant contribution factor k

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

2008-01-01

37

Saturation densities of new refrigerant mixtures  

Microsoft Academic Search

As has been shown in preceding papers, the vapour–liquid equilibria of binary and ternary mixtures of new refrigerants can be calculated mostly within experimental accuracy using simple cubic equations of state. The parameters of these equations are based on properties of the pure substances and on only a few experimental data of a nearly equimolar mixture of the relevant binary

M. Nagel; K. Bier

1998-01-01

38

The optimal design of refrigerant mixtures for a two-evaporator refrigeration system  

Microsoft Academic Search

The use of liquid-phase mixtures is common in a number of industrial applications. Mixtures have certain advantages over individual components, and these have been exploited advantageously. For the case of refrigerants, a number of azeotropic mixtures are used in practise. The use of non-azeotropic refrigerant mixtures, however, is not as common. This paper looks at the design of refrigerant mixtures

Nachiket Churi; Luke E. K. Achenie

1997-01-01

39

Ideal-Gas Heat Capacity Values and Equations for Hydrofluorocarbon (HFC) Refrigerants Based on Speed-of-Sound Measurements  

Microsoft Academic Search

Final values of ideal-gas heat capacity c0p derived from speed-of-sound measurements using an acoustic spherical resonator and equations of c0p as a simple function of temperature are provided from an overall assessment of speed-of-sound measurements for five hydrofluorocarbon (HFC) refrigerants, difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), and 1,1-difluoroethane (R152a). Some of the experimental results had systematic errors in

H. Sato; T. Kojima; K. Ogawa

2002-01-01

40

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

EPA Science Inventory

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

41

Relative permittivity and resistivity of liquid HFC refrigerants under high pressure  

SciTech Connect

The static relative permittivity (dielectric constant) and the resistivity of HFC-236ea (CF{sub 3}-CHF-CHF{sub 2}) and HFC-245fa (CF{sub 3}-CH{sub 2}-CHF{sub 2}) in the liquid phase were studied at temperatures from 293 to 343 K and pressures from 0.1 to 50 MPa. The relative permittivity was measured by a concentric-cylinder-type capacitance cell with an LCR meter with an uncertainty of less than 0.1%. The resistivity was measured by a high resistance meter using plane-parallel platinum electrodes installed in a borosilicate glass syringe. It was found that the relative permittivities and the resistivities of liquid HFC-236ea and HFC-245fa at 303 K and 0.101325 MPa are about 5.13 and 6.54 and 1.5 {times} 10{sup 10} and 0.2 {times} 10{sup 10} {Omega} {center_dot} cm, respectively. The relative permittivity and the resistivity increase monotonically with increasing pressure and decreasing temperature.

Tanaka, Y.; Matsuo, S.; Sotani, T.; Kondo, T.; Matsuo, T. [Kobe Univ. (Japan). Dept. of Chemical Science and Engineering

1999-01-01

42

Performance of environmentally friendly CFC-12 replacements for refrigerator/freezers  

SciTech Connect

The paper presents the capacity and energy consumption of refrigerant replacements for HFC-134a and/or CFC-12 as determined by experimental testing and analysis. Refrigerator/freezer (R/F) tests were run according to the Association of Home Appliance Manufacturer`s testing conditions in an environmental test chamber. The charge was optimized for each refrigerant, and the results were compared to those for HFC-134a and CFC-12. The numerical model and experiment results were compared to verify the model. The paper investigates HFC-245cb/HFC-134 and HFC-134. Computer modeling predicts that these azeotropes will perform similarly to HFC-134a, which has a higher global warming potential than any of the mixtures except HFC-245cb/HFC-134.

Baskin, E.; Bayoglu, E.S.; Delafield, F.R.

1995-12-31

43

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

PubMed

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

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

2009-12-15

44

HFC134a\\/HC600a\\/HC290 mixture a retrofit for CFC12 systems  

Microsoft Academic Search

The environmental concerns with the impact of refrigerant emissions lead to the importance in identifying a long-term alternative to meet all requirements in respect of system performance and service. Even though HFC134a and HC blend (containing 55.2% HC600a and 44.8% HC290 by weight) have been reported to be substitutes for CFC12, they have their own drawbacks in respect of energy

S. J. Sekhar; D. M. Lal

2005-01-01

45

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

SciTech Connect

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

Gunsel, Selda; Pozebanchuk, Michael

1999-04-01

46

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...

47

Global warming from HFC  

SciTech Connect

Using a variety of public sources, a computer model of hydrofluorocarbon (HFC) refrigerant emissions in the UK has been developed. This model has been used to estimate and project emissions in 2010 under three types of scenarios: (1) business as usual; (2) voluntary agreements to reduce refrigerant leakage; and (3) comprehensive regulations to reduce refrigerant leakage. This resulting forecast is that UK emissions of HFC refrigerants in 2010 will account for 2% to 4% of the UK`s 1990 baseline global warming contribution.

Johnson, E. [Atlantic Consulting, London (United Kingdom)

1998-11-01

48

Experimental investigation on condensation heat transfer and pressure drop of new HFC refrigerants (R134a, R125, R32, R410A, R236ea) in a horizontal smooth tube  

Microsoft Academic Search

This paper reports experimental heat transfer coefficients and pressure drops measured during condensation inside a smooth tube when operating with pure HFC refrigerants (R134a, R125, R236ea, R32) and the nearly azeotropic HFC refrigerant blend R410A. Data taken when condensing HCFC-22 are also reported for reference. The experimental runs are carried out at a saturation temperature ranging between 30 and 50°C,

A. Cavallini; G. Censi; D. Del Col; L. Doretti; G. A. Longo; L. Rossetto

2001-01-01

49

Releases of refrigerant gases (CFC12, HCFC22 and HFC134a) to the atmosphere  

Microsoft Academic Search

Two of the gases, CFC-12 (dichlorodifluoromethane, CF2Cl2) and HCFC-22 (chlorodifluoromethane, CHClF2) 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

Archie McCulloch; Pauline M Midgley; Paul Ashford

2003-01-01

50

Tubeside evaporation of nonazeotropic refrigerant mixtures from two enhanced surfaces  

Microsoft Academic Search

As part of the Building Equipment Research program at Oak Ridge National Laboratory, nonazeotropic refrigerant mixtures (NARMs) are being investigated to replace chlorofluorocarbon compounds. The evaporation of NARMs is not isothermal, and this can improve the heat exchanger effectiveness of an evaporator as well as improve thermodynamic cycle efficiencies. The evaporating heat transfer coefficient for four nonazeotropic mixtures of refrigerants

J. C. Conklin; E. A. Vineyard

1990-01-01

51

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

SciTech Connect

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

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

1997-07-01

52

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

SciTech Connect

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

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

1997-06-01

53

Recent Progress in Thermophysical Properties Research of Nonazeotropic Refrigerant Mixtures  

NASA Astrophysics Data System (ADS)

This article begins to describe some general thermodynamic behaviors of mixtures as well as the overview of the previously reported feasibility studies related to the performance test and the cycle analysis of the reversed Rankine cycle system with refrigerant mixtures. The current state of the art for the equilibrium and non-equiliburium properties of nonazeotropic refrigerant mixtures is then reviewed. The present review shows that the absolute quantity and quality of information about the thermophysical properties are still limited. Concerning the equilibrium properties, vapor-liquid equilibrium data are available for quite a few refrigerant mixtures, but most of them are in the limited range of temperature and pressure. PVTx data for several refrigerant mixtures are also available but scarce with respect to the calorimetric and other properties. Experimental studies concerning the non-equilibrium properties, on the other hand, have recently begun to reveal the temperature, pressure and composition dependence of the viscosity and thermal conductivity in gaseous phase for several refrigerant mixtures. It is, therefore, concluded that further experimental studies of both equilibrium and non-equilibrium properties should be made so as to develop estimation methods to correlate mixture properties more precisely as well as to promote practical applications of the nonazeotropic refrigerant mixtures in the advanced vaporcompression refrigeration and heat pump cycles.

Takaishi, Yoshinori; Watanabe, Koichi

54

Vapor-liquid equilibrium, coexistence curve, and critical locus for binary HFC-32/HFC-134a mixture  

NASA Astrophysics Data System (ADS)

Two kinds of equilibrium measurements of binary R-32/134a mixtures were carried out. The vapor-liquid equilibria were measured by the static method in the temperature range between 283 and 313 K. On the basis of the present experimental data, the temperature dependence of the binary interaction parameter k 12 for two equations of state, namely, the Soave-Redlich-Kwong equation and Carnahan-Starling-De Santis equation, was discussed. The vapor-liquid coexistence curve near the critical point was also measured by the observation of meniscus disappearance. The critical temperatures and critical densities of 30 and 70 wt% R-32 mixtures were determined on the basis of the saturation densities along the coexistence curve in the critical region. In addition, a correlation of the critical locus for this mixture is proposed as a function of composition.

Higashi, Y.

1995-09-01

55

Two-phase heat transfer coefficients of three HFC refrigerants inside a horizontal smooth tube, part I: evaporation  

Microsoft Academic Search

This paper presents experimental heat transfer results obtained during the evaporation of Isceon 59, R407C and R404A in a horizontal tube. The results have been compared with existing correlations which characterise the evaporative heat transfer coefficient to assess the validity of these models for refrigerant mixtures. The results compared well with the (Gungor K.E., Winterton, R.H.S. Simplified general correlation for

X. Boissieux; M. R. Heikal; R. A. Johns

2000-01-01

56

Vapor-liquid equilibrium, coexistence curve, and critical locus for binary HFC32\\/HFC134a mixture  

Microsoft Academic Search

Two kinds of equilibrium measurements of binary R-32\\/134a mixtures were carried out. The vapor-liquid equilibria were measured by the static method in the temperature range between 283 and 313 K. On the basis of the present experimental data, the temperature dependence of the binary interaction parameterk12 for two equations of state, namely, the Soave-Redlich-Kwong equation and Carnahan-Starling-De Santis equation, was

Y. Higashi

1995-01-01

57

Evaluation of vapor compression cycles using nonazeotropic refrigerant mixtures  

NASA Astrophysics Data System (ADS)

A comprehensive investigation is carried out, on a systematic and consistent basis, to explore a range of advanced heat pump cycle concepts using nonazeotropic refrigerants for COP enhancement and capacity modulation along with the trade-offs associated with refrigerant mixture selection. The objectives of the study were to: identify candidate nonazeotropic mixtures and advanced heat pump cycle concepts with emphasis on their potential for single-speed capacity modulation with mixture composition control; assess the effect of conjunction with nonazeotropic mixture cycles; evaluate the cycles analytically and recommend the most promising cycles and mixtures for further development; and provide recommendations relating to the needs for additional refrigerant property data, experimental studies of basic heat transfer phenomena with mixed refrigerants, development of system components, and/or more detailed modeling of specific components.

Merriam, Richard L.

58

Modified Peng-Robinson Equation of State for Pure and Mixture Refrigerants with R-32,R-125 and R-134a  

NASA Astrophysics Data System (ADS)

On the basis of critically-evaluated thermodynamic property data among those recently published, a new Peng-Robinson equation of state for the HFC refrigerants,R-32,R-125 and R-134a,has be end eveloped so as to represent the VLE properties in the vapor-liquid coexisting phase at temperatures 223K-323K. In accord with a challenge to correlate the binary and/or ternary interatction parameters as functions of temperature, we have also applied the present modified Peng-Robinson equation of state to the promising alternative HFC refrigerant mixtures, i.e., R-32/125,R-32/134a and R-32/125/134a systems. The developed equation of state improves significantly its effectiveness for practical engineering property calculations at refrigerantion and air-conditioning industries in comparison with conventional Peng-Robinson equation.

Ll, Jin; Sato, Haruki; Watanabe, Koichi

59

Tubeside condensation of nonazeotropic refrigerant mixtures for two enhanced surfaces  

Microsoft Academic Search

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

J. C. Conklin; E. A. Vineyard

1990-01-01

60

Tubeside condensation of nonazeotropic refrigerant mixtures for two enhanced surfaces.  

National Technical Information Service (NTIS)

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 ca...

J. C. Conklin E. A. Vineyard

1990-01-01

61

Tubeside evaporation of nonazeotropic refrigerant mixtures from two enhanced surfaces.  

National Technical Information Service (NTIS)

As part of the Building Equipment Research program at Oak Ridge National Laboratory, nonazeotropic refrigerant mixtures (NARMs) are being investigated to replace chlorofluorocarbon compounds. The evaporation of NARMs is not isothermal, and this can improv...

J. C. Conklin E. A. Vineyard

1990-01-01

62

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

63

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

NASA Astrophysics Data System (ADS)

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

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

64

Materials Compatibility and Lubricants Research on CFC-refrigerant substitutes. Quarterly MCLR Program technical progress report, July 1--September 30, 1995  

SciTech Connect

The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. This report summarizes the research conducted during the third quarter of calendar year 1995 on the following projects: Thermophysical properties of HCFC alternatives; Compatibility of manufacturing process fluids with HFC refrigerants and ester lubricants; Compatibility of motor materials used in air-conditioning for retrofits with alternative refrigerants and lubricants; Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants; Products of motor burnouts; Accelerated test methods for predicting the life of motor materials exposed to refrigerant-lubricant mixtures; Investigation of flushing and clean-out methods; Investigation into the fractionation of refrigerant blends; Lean flammability limits as a fundamental refrigerant property; Effect of selected contaminants in AC and R equipment; Study of foaming characteristics; Study of lubricant circulation in systems; Evaluation of HFC-245ca for commercial use in low pressure chillers; Infrared analysis of refrigerant mixtures; Refrigerant database; Refrigerant toxicity survey; Thermophysical properties of HFC-32, HFC-123, HCFC-124 and HFC-125; Thermophysical properties of HFC-143a and HFC-152a; Theoretical evaluations of R-22 alternative fluids; Chemical and thermal stability of refrigerant-lubricant mixtures with metals; Miscibility of lubricants with refrigerants; Viscosity, solubility and density measurements of refrigerant-lubricant mixtures; Electrohydrodynamic enhancement of pool and in-tube boiling of alternative refrigerants; Accelerated screening methods; and more.

Szymurski, S.R.; Hourahan, G.C.; Godwin, D.S.; Amrane, K.

1995-10-01

65

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

SciTech Connect

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

Henderson, D.R.

1993-10-01

66

Advantages of enthalpy-temperature diagrams for nonazeotropic refrigerant mixtures  

NASA Astrophysics Data System (ADS)

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

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

1991-08-01

67

Measurement of viscosity, density, and gas solubility of refrigerant blends in selected synthetic lubricants. Final report  

SciTech Connect

The lubricants tested in this project were chosen based on the results of liquid/liquid miscibility tests. EMKARATE RL32S and Emery 2968A were selected. The Vapor Liquid Equilibrium (VLE) viscosity reduction and gas fractionation of each was measured with three different refrigerant blends: (1) R-404A; (2) R-507; and (3) R-407C. In addition, the four single refrigerants that make up the blends, HFC-32, HFC-125, HFC-134a, and HFC-143a, were also measured. Lubricants found to have the lowest liquid/liquid miscibilities had nearly equal viscosity reduction profiles as did the more miscible lubricants. Analytical methodology consisted of maintaining equally both the composition of the head space vapor above the lubricant/refrigerant mixture, and the composition of the liquid blend refrigerant. Blends with large temperature glides were re-evaluated in order to test the concept of head space quality and a vented piston hydraulic cylinder assembly was developed to perform this task. Fluid property data, above critical temperature and pressure conditions, is presented for the two lubricants with HFC-32, HFC-125, HFC-143a refrigerants. This research shows that the lubricant EMKARATE RL32S, which had the lowest (poorest) liquid/liquid miscibilities with the selected refrigerants, also had nearly equal viscosity reduction profiles to the more miscible Emery 2968A lubricant. The analytical methodology consisted of maintaining the composition of the refrigerant gas above the lubricant to be equal in composition to that of the pure liquid refrigerant blend being introduced into the lubricant. Refrigerant blends with large temperature glides were re-evaluated in order to validate the concept of the importance of the composition of the gas over the lubricant. To do perform this task, a special vented piston hydraulic cylinder assembly was developed. Fluid property data is also presented for HFC-32, HFC-125, and HFC-143a above the critical temperature and pressure of each.

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

1995-05-15

68

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

69

Heat exchanger thermal performance for two nonazeotropic refrigerant mixtures.  

National Technical Information Service (NTIS)

Two nonazeotropic refrigerant mixtures (NARMs), the first consisting of 71% R22 and 29% R114 and the second consisting of 75% R143a and 25% R124 (approximate percentages by mass), were studied at various mass flow rate and heat loads in an experimental ap...

J. C. Conklin E. A. Vineyard

1991-01-01

70

An analysis of gas separation processes of HFC134a from gaseous mixtures with nitrogen—Comparison of two types of gas separation methods, liquefaction and hydrate-based methods, in terms of the equilibrium recovery ratio  

Microsoft Academic Search

Two types of gas separation methods, using liquefaction and gas hydrate formation, were compared in terms of the equilibrium recovery ratio for the separation of gaseous mixtures of HFC-134a and nitrogen. The equilibrium recovery ratio is defined as the molar ratio of the target component (HFC-134a, in the present case) recovered in the condensed (recovered) phase to that in the

Toru Nagata; Hideo Tajima; Akihiro Yamasaki; Fumio Kiyono; Yutaka Abe

2009-01-01

71

Foaming characteristics of refigerant/lubricant mixtures  

SciTech Connect

The air-conditioning and refrigeration industry has moved to HFC refrigerants which have zero ozone depletion and low global warming potential due to regulations on CFC and HCFC refrigerants and concerns for the environment. The change in refrigerants has prompted the switch from mineral oil and alkylbenzene lubricants to polyolester-based lubricants. This change has also brought about a desire for lubricant, refrigerant and compressor manufacturers to understand the foaming properties of alternative refrigerant/ lubricant mixtures, as well as the mechanisms which affect these properties. The objectives of this investigation are to experimentally determine the foaming absorption and desorption rates of HFC and blended refrigerants in polyolester lubricant and to define the characteristics of the foam formed when the refrigerant leaves the refrigerant/ lubricant mixture after being exposed to a pressure drop. The refrigerants being examined include baseline refrigerants: CFC-12 (R-12) and HCFC-22 (R-22); alternative refrigerants: HFC-32 (R-32), R-125, R-134a, and R-143a; and blended refrigerants: R-404A, R-407C, and R-410A. The baseline refrigerants are tested with ISO 32 (Witco 3GS) and ISO 68 (4GS) mineral oils while the alternative and blended refrigerants are tested with two ISO 68 polyolesters (Witco SL68 and ICI RL68H).

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

1997-04-01

72

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, 2010 CFR

...Recharging Equipment for HFC-134a Refrigerant C Appendix C to Subpart B of Part...Recharging Equipment for HFC-134a Refrigerant Foreword This Appendix establishes...of performance and durability as new refrigerant. 1. Scope The purpose...

2009-07-01

73

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, 2010 CFR

...Recharging Equipment for HFC-134a Refrigerant C Appendix C to Subpart B of Part...Recharging Equipment for HFC-134a Refrigerant Foreword This Appendix establishes...of performance and durability as new refrigerant. 1. Scope The purpose...

2010-07-01

74

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

EPA Science Inventory

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

75

Tubeside evaporation of nonazeotropic refrigerant mixtures from two enhanced surfaces  

SciTech Connect

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

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

1990-01-01

76

Heat exchanger thermal performance for two nonazeotropic refrigerant mixtures  

Microsoft Academic Search

Two nonazeotropic refrigerant mixtures (NARMs), the first consisting of 71 percent R22 and 29 percent R114 and the second consisting of 75 percent R143a and 25 percent R124 (approximate percentages by mass), were studied at various mass flow rates and heat loads in an experimental apparatus at Oak Ridge National Laboratory. The measured thermal performance of the evaporator and the

J. C. Conklin; E. A. Vineyard

1991-01-01

77

Evaluation of nonazeotropic refrigerant mixtures for capacity modulation  

SciTech Connect

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

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

1988-01-01

78

Heat transfer evaluation of HFC-236ea and CFC-114 in condensation and evaporation. Final report, October 1992-March 1995  

SciTech Connect

The report gives results of a heat transfer evaluation of the refrigerants hexafluoropropane (HFC-236ea) and 1,1,2,2-dichloro-tetrafluoroethane (CFC-114). This research focuses on comparing the refrigerants not only in condesation and pool boiling, but also with various tube surfaces. The test facility used in this study was initially used for spray evaporation testing; however, it was redesigned and modified for use with condensation, pool boiling, or spray evaporation testing. During condensation, the rig was capable of producing saturated or superheated vapor. During pool boiling or spray evaporation, the test facility was capable of testing pure refrigerants or refrigerant/lubricant mixtures.

Huebsch, W.W.; Pate, M.B.

1996-06-01

79

Mixing rules for the specific heat capacities of several HFC-mixtures  

Microsoft Academic Search

The specific heat capacity at constant pressure (cp) of some relevant HFCs as replacements for R12, R502 and R22 was measured. The liquids investigated are binary or ternary mixtures of R134a, R152a, R125, R32 and R143a. Empirical functional relations in polynomial forms between the temperature, specific heat capacity and concentration are established and the coefficients of the polynomial correlations are

D Günther; F Steimle

1997-01-01

80

Simulation and performance of a system using an R-12\\/R-114 refrigerant mixture  

Microsoft Academic Search

The objective of this combined analytical and experimental study is to determine energy conservation possibilities through the use of a refrigerant mixture in a refrigerator or heat pump. The system is one with two evaporators that are operated at different temperatures levels, and the basic approach was to maintain constant refrigeration loads and temperatures throughout a series of tests wherein

W. F. Stoecker; C. I. McCarthy

1984-01-01

81

Some Correlations for Saturated-Liquid Density of Refrigerant Mixtures  

NASA Astrophysics Data System (ADS)

Three methods to correlate and estimate the saturated-1iquid density of refrigerant mixtures are compared and evaluated on the basis of the measurements for five bibary and one ternary mixtures performed by the present authors. The first of them is a method using Peng-Robinson equation (PR-method) proposed originally by Peneloux et al. Since this method dose not require any measurements of the saturated-liquid density of mixture, it is useful for the estimation. However, the applicability of this method to various substances may be restricted. The second is the modified Rackett equation proposed by Spencer and Dannar (mR-method). The temperature functional form of this equation is quite simple, so it is useful to use it as a functional form of the fitting. Unfortunately this method can not be used for strongly non-ideal mixtures. The last one is the Hankinson-Brobst-Thomson equation (HBT-method). This method can provide the most accurate density values among the three methods with two kinds of binary parameters where these binary parameters are introduced by the present authors. In the case that many experimental saturated liquid densities of mixtures are available in the wide range of temperatures, the HBT-method is recommended for the practical use.

Maezawa, Yukishige; Sato, Haruki; Watanabe, Koichi

82

Vapour-liquid equilibrium data for binary mixtures of some new refrigerants  

Microsoft Academic Search

The acceptance of the Montreal Protocol has led to a timetable for the phasing out of chlorine-containing refrigerants and their replacement by new chlorine-free materials. For many applications a pure alternative refrigerant can not be found with the appropriate properties and refrigerant mixtures have been considered. In order to model the properties of these refrigerant blends accurate vapour-liquid equilibrium (VLE)

M. H. Barley; J. D. Morrison; A. O'Donnel; I. B. Parker; S. Petherbridge; R. W. Wheelhouse

1997-01-01

83

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

Microsoft Academic Search

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

Xianping Zhang; Aidong Chen; Huanlin Duan

2010-01-01

84

Influence of Refrigerant Oil on Evaporator Performance  

NASA Astrophysics Data System (ADS)

Because of the phase-out CFC Freon series required by Montreal Protocal, the conversion to HFC alternatives for vapor compression refrigeration system have been in progress. The each component design of these system should need to be reassessed, however, to improve the performance and compactness of the evaporator, an influence of the refrigerant oil on the refrigerant side heat transfer remains as an important and unsolved subject. In this article, the previous research progresses on the thermophysical properties, two-phase flow regimes and heat transfer in evaporator tube of refrigerant and oil mixture are briefly reviewed and the ability of these results to the combination of the alternative refrigerant and oil system is discussed. According to the review, the limited quantitative agreements were obtained from the perfect miscible refrigerant and oil mixture and, in particular, the much detailed research on the heat transfer mechanisms are required in future.

Kim, Jong Soo; Katsuta, Masafumi

85

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

SciTech Connect

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

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

1992-01-01

86

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

SciTech Connect

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

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

1992-11-01

87

A heat exchanger model for mixtures and pure refrigerant cycle simulations  

Microsoft Academic Search

This paper describes a heat exchanger simulation developed for transient and steady state cycle simulations of mixtures and pure components. The simulation focuses on air to refrigerant condensers and evaporators found in residential heat pumps. The refrigerant differential momentum, continuity, species and energy equations are solved for these components and the steady state results are verified experimentally. Ten different heat

John Judge; Reinhard Radermacher

1997-01-01

88

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...

89

Heat exchanger thermal performance for two nonazeotropic refrigerant mixtures  

NASA Astrophysics Data System (ADS)

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

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

1991-08-01

90

Oil concentration variation for bottled refrigerant/oil mixtures during extraction  

NASA Astrophysics Data System (ADS)

In order to cut down setup cost for maintaining a constant concentration of oil in refrigerant/oil mixtures during experimentation, a bottle filled with a refrigerant/oil mixture having a predetermined oil concentration occurs as a suitable option. An attempt has been made to find the limits of variation in oil concentration during the extraction process so that the above technique can be suitably employed. Cases for oil with specific gravity in the range 0.80-1.00 and three refrigerants, viz., CO2, R290 and R134a are analysed. A sharp rise in oil concentration is revealed toward the end of the extraction process. It is proposed that oil concentration variation can be constrained by supplying the lowest residual/left mass fraction ( LMF) value (or the maximum extractable mixture weight) along with other specifications for the refrigerant/oil mixture. A correlation is obtained to determine oil concentration during various stages of the extraction process.

Yadav, Vipin

2012-01-01

91

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

Microsoft Academic Search

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

Baolian Niu; Yufeng Zhang

2007-01-01

92

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

... PROTECTION OF STRATOSPHERIC OZONE Servicing of Motor Vehicle...maintenance or replacement that affect the proper operation of the...from flammable refrigerants and health hazards from toxic refrigerants...modified in any way that could affect system performance for...

2009-07-01

93

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

... PROTECTION OF STRATOSPHERIC OZONE Servicing of Motor Vehicle...maintenance or replacement that affect the proper operation of the...from flammable refrigerants and health hazards from toxic refrigerants...modified in any way that could affect system performance for...

2010-07-01

94

Flow Regimes of Refrigerant Mixtures Condensing inside Tubes.  

National Technical Information Service (NTIS)

This study sought more insight into the condensation process by observing and photographing the flow regimes of the same nonazeotropic mixed refrigerants condensing in a single-tube glass condenser. Measurements of pressure and temperature profiles throug...

E. Kornota W. F. Stoecker

1985-01-01

95

Polyol esters as HFC-134a compressor lubricants  

SciTech Connect

A polyol ester-based lubricant has been applied to HFC-134a household refrigerator compressors, because of its good miscibility with HFC-134a refrigerant, and there is a possibility that it will be applied to automobile air conditions. For better performance, further improvements are needed regarding miscibility, lubricity and chemical stability of the lubricant, because such systems are often used under extreme conditions. This report discusses the required properties and ways to improve performance of polyol esters as HFC-134a compressor lubricants. 7 refs., 14 figs., 4 tabs.

Komatsuzaki, S.; Homma, Y.; Itoh, Y. [Hitachi Ltd. (Japan)] [and others

1994-10-01

96

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...

97

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...

98

Performance Evaluation of Chlorine Free Zeotropic Refrigerant Mixtures in Heat Pumps Computer Study and Tests.  

National Technical Information Service (NTIS)

Fifteen binary zeotropic refrigerant mixtures consisting of the components R 23, R32, R125, R134a, , R143a, and R152a are investigated as possible replacement fluids for R22. The two mixtures of R32/R134a abd R32/R152a showed COP imporvements over R22 of ...

D. A. Didion J. Pannock R. Radermacher

2003-01-01

99

Cycle performance comparison between a nonazeotropic refrigerant mixture and R22  

Microsoft Academic Search

In an effort to improve the efficiency of residential heat pumps and reduce the ozone depletion potential (ODP) of the refrigerant, nonazeotropic mixtures (NARMs) are being investigated as part of the Building Equipment Research program at Oak Ridge National Laboratory (ORNL). One of the NARMs, a mixture consisting of approximately 75% R143a and 25% R124 (percentages by mass) was tested

E. A. Vineyard; J. C. Conklin

1991-01-01

100

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

EPA Science Inventory

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

101

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...

102

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

Microsoft Academic Search

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

Aleksandr Vasserman C; Valentine Malchevsky S

103

Vapor-liquid equilibria of alternative refrigerants and their binaries by molecular simulations  

Microsoft Academic Search

Alternative refrigerants HFC125 (CHF2CF3), HFC 134a (CF3CH2F) are modeled as a dipolar two-center Lennard-Jones fluid and alternative refrigerant HFC32 (CH2F2) is modeled as a dipolar Lennard-Jones fluid. We calculate vapor- liquid equilibria of these refrigerants by Gibbs -Duhem integration and vapor- liquid equilibria of two binaries (HFC 125+HFC 134a, and HFC 134a+HFC 32) by the reaction Gibbs ensemble Monte Carlo

R. Budinsky; V. Vacek; M. Lisal

104

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...

105

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

106

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

107

Performance of chlorine-free binary zeotropic refrigerant mixtures in a heat pump  

SciTech Connect

The phase-out of the currently used refrigerants during the next decade requires fast and accurate methods to evaluate possible alternatives for the existing refrigerants. The report investigates possible replacement refrigerants for R22, where the replacements are binary zeotropic mixtures of the following hydrofluorocarbons (HFCs): R23, R32, R125, R134a, and R152a. The method, that was chosen, is based on three steps: (1) determining possible mixture components, (2) evaluating all fifteen possible mixtures using a simulation program developed by NIST and determining the best performing mixtures, (3) evaluating the best performing mixtures in a NIST built test facility. Following the path, two refrigerant mixtures, R32/R134a and R32/R152a were found to perform better than R22 with respect to COP and volumetric capacity for certain composition ranges. The used simulation model proved to be a very precise tool in finding possible replacement fluids and their possible performance advantages. The results give the confidence that this time saving combination of simulation and testing is a very powerful engineering tool.

Pannock, J.; Didion, D.A.

1991-12-01

108

Effect of dissolved lubricating oils on the viscosity of alternative refrigerants  

SciTech Connect

The operation of refrigeration systems involves the circulation of a working fluid which is actually a mixture of refrigerant and lubricant oil. Since the viscosity of oil and that of refrigerants normally differ by up to a factor of 4, the effect of dissolved oil is very large. In order to use new alternative refrigerants, accurate information on thermophysical properties of refrigerant-oil mixtures is needed. In the present study, the viscosity of refrigerant oil mixtures was measured for HCFC-123 + 3GSD and HFC-134a + PAG in the compressed liquid region with a falling-ball viscometer. The temperature range of the measurements was 253-333 K. 15 refs., 6 figs., 5 tabs.

Chang, Y.N.; Nagashima, A. (Keio Univ., Yokohama (Japan))

1993-09-01

109

Thermodynamic calculations for mixtures of environmentally safe refrigerants using the Lee-Kesler-Ploecker equation of state  

Microsoft Academic Search

The imminent phaseout of R-11, R-12, and R-115 because of their high ozone depletion potentials has prompted many independent investigations of alternative or substitute refrigerants, either as pure compounds or as mixtures of two or more environmentally acceptable fluids. There are several motivations for investigating mixtures. There are very few pure compounds which can be used for refrigerants that are

Steven K. Fischer; Jim R. Sand

1990-01-01

110

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

SciTech Connect

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

Kauffman, R.

1993-04-01

111

Moderately high temperature water source heat-pumps using a near-azeotropic refrigerant mixture  

Microsoft Academic Search

A ternary mixture of R124\\/R142b\\/R600a, named HTR01, for moderately high temperature heat pumps, was developed. Tests of material compatibility and oil miscibility showed that the mixture could be used with a R22 compressor in an HTR01 heat-pump system. A 2.92 kW moderately high temperature water source heat pump system was set up with HTR01 as the refrigerant to study the

Liu Nanxi; Lin Shi; Han Lizhong; Zhu Mingshan

2005-01-01

112

Pool boiling heat transfer of refrigerant mixtures R32\\/R125  

Microsoft Academic Search

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

Jianya Shen; Klaus Spindler; Erich Hahne

1999-01-01

113

Wet compression versus dry compression in heat pumps working with pure refrigerants or non-azeotropic binary mixtures for different heating applications  

Microsoft Academic Search

Wet compression versus dry compression in heat pumps working with pure refrigerants or non-azeotropic binary mixtures is investigated in this paper. In total 34 pure refrigerants as well as 31 non-azeotropic binary mixtures at different concentrations are considered. This resulted in approximately 300 different mixtures being analysed. The pure refrigerants were analysed for three different heating applications found in practice:

P. P. J Vorster; J. P Meyer

2000-01-01

114

Measurement of solubility, viscosity, and density of R-410A refrigerant/lubricant mixtures  

SciTech Connect

Measurements of the refrigerant vapor/liquid lubricant equilibrium viscosity reduction of four polyolester lubricants, viscosity grades 32 and 68 ISO VG, with the refrigerant R-410A were taken between {minus}13 F and 257 F and up to 700 psia. A high and low miscibility grade polyolester was analyzed for each viscosity. The viscosity, density, and composition of the solubilized gas mixture in solution with the lubricant was obtained with constant gas vapor composition in the viscometer head space. This refrigerant has a very small temperature glide but is considered a zeotropic blend nonetheless. The fractionation data presented were obtained from individual isothermal measurements. The isotherm for each temperature detailed the composition of the equilibrium gas fractionation of R-32 and R-125 in the lubricant, mixed vapor pressure, concentration of the total mixed blend (percent by weight) in the lubricant, and viscosity in centipoise (cP) and centistokes (cSt).

Cavestri, R.C.; Schafer, W.R.

2000-07-01

115

Performance Improvement of Pulse Tube Refrigerator for Space Application with Helium-hydrogen mixture  

NASA Astrophysics Data System (ADS)

Weight or size of the cryocoolers used is a key factor in space applications This can be acquired by the selection of high efficiency cryocoolers or through the optimization of structural parameters. Given the type of regenerator, another way to improve the cooling performance is the adoption of gas mixture instead of pure helium as the working fluids. Gas mixtures have been proved very useful to J-T cryocoolers at 80K temperature range. In this paper, we do some theoretical and experimental study to probe into the possibility of using gas mixture to improve the coefficient of performance of regenerative cryocoolers such as pulse tube refrigerators. The performance comparison of regenerator using helium-hydrogen mixtures to pure helium gas is presented based on the analysis of the heat transfer and fluid flow. The pressure drop for helium-hydrogen mixture decreased more rapidly than the increase of thermal loss compared with pure helium, so the improvement of overall regenerator performance can be obtained. Experiments have been done with helium-hydrogen mixture in a coaxial valveless pulse tube refrigerator. Experimental results show that the cooling capacity with He-H2 mixture is 10~20 percent larger than that with pure helium, which is in coincidence with the theoretical analysis.

Chen, G. B.; Yu, J. P.; Gan, Z. H.

116

First principles predictions of thermophysical properties of refrigerant mixtures  

NASA Astrophysics Data System (ADS)

We present pair potentials for fluorinated methanes and their dimers with CO2 based on ab initio potential energy surfaces. These potentials reproduce the experimental second virial coefficients of the pure fluorinated methanes and their mixtures with CO2 without adjustment. Ab initio calculations on trimers are used to model the effects of nonadditive dispersion and induction. Simulations using these potentials reproduce the experimental phase-coexistence properties of CH3F within 10% over a wide range of temperatures. The phase coexistence curve of the mixture of CH2F2 and CO2 is reproduced with an error in the mole fractions of both phases of less than 0.1. The potentials described here are based entirely on ab initio calculations, with no empirical fits to improve the agreement with experiment.

Oakley, Mark T.; Do, Hainam; Hirst, Jonathan D.; Wheatley, Richard J.

2011-03-01

117

First principles predictions of thermophysical properties of refrigerant mixtures.  

PubMed

We present pair potentials for fluorinated methanes and their dimers with CO(2) based on ab initio potential energy surfaces. These potentials reproduce the experimental second virial coefficients of the pure fluorinated methanes and their mixtures with CO(2) without adjustment. Ab initio calculations on trimers are used to model the effects of nonadditive dispersion and induction. Simulations using these potentials reproduce the experimental phase-coexistence properties of CH(3)F within 10% over a wide range of temperatures. The phase coexistence curve of the mixture of CH(2)F(2) and CO(2) is reproduced with an error in the mole fractions of both phases of less than 0.1. The potentials described here are based entirely on ab initio calculations, with no empirical fits to improve the agreement with experiment. PMID:21428643

Oakley, Mark T; Do, Hainam; Hirst, Jonathan D; Wheatley, Richard J

2011-03-21

118

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...

119

Tribological evaluation of some aluminum-based materials in lubricant\\/refrigerant mixtures  

Microsoft Academic Search

The tribological characteristics of various aluminum alloys, surface treated 356 aluminum alloy and an aluminum composite are evaluated in lubricant\\/refrigerant (L\\/R) mixtures. The evaluation is based on a cylindrical pin\\/disc line contact geometry. This research program consists of two parts. The first part focuses mainly on materials screening of various aluminum\\/steel contact pairs lubricated by polyolester\\/R134a (tetrafluoroethane) and polyalkylene glycol

Hyung Yoon; Todor Sheiretov; Cris Cusano

1998-01-01

120

Vapor–liquid equilibria of alternative refrigerants and their binaries by molecular simulations employing the reaction Gibbs ensemble Monte Carlo method  

Microsoft Academic Search

Alternative refrigerants HFC125 (CHF2CF3) and HFC 134a (CF3CH2F) are modeled as a dipolar two-center Lennard–Jones fluid and alternative refrigerant HFC32 (CH2F2) is modeled as a dipolar Lennard–Jones fluid. We calculate vapor–liquid equilibria of these refrigerants by Gibbs–Duhem integration and vapor–liquid equilibria of two binaries (HFC 125 + HFC 134a and HFC 134a + HFC 32) by the reaction Gibbs ensemble

R. Budinský; V. Vacek; M. L??sal

2004-01-01

121

Chemical and thermal stability of refrigerant-lubricant mixtures with metals  

SciTech Connect

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

Huttenlocher, D.F.

1992-10-09

122

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

SciTech Connect

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

Huttenlocher, D.F.

1992-10-09

123

Selection of ozone-safe, nonazeotropic refrigerant mixtures for capacity modulation in residential heat pumps  

SciTech Connect

Many combinations of refrigerants have been tested in an effort to improve the efficiency of residential heat pumps. Up to this point, there has been no systematic approach for determining which fluid pairs have the greatest potential for improving heat pump performance. The primary purpose of this work was to perform a comprehensive screening of refrigerant pairs which, through a shift in composition, could improve the performance of heat pump systems by modulating their capacity to better follow a building load. Secondary goals were to select a mixture with (1) a gliding temperature difference that matches that of the heat transfer fluid in both heat exchangers and (2) a higher capacity relative to R22 at low outdoor temperatures. The number of pure components was pared on the basis of boiling point, stability, ozone depletion potential, and toxicity. Pairs were then assembled from the pure components using the temperature glide (the constant-pressure temperature change that the fluid undergoes in the two-phase region as it passes through the heat exchanger) and the coefficient of performance to determine those pairs with the highest potential. The conclusions were that mixtures of R32/R124, R32/R142b, R143a/R124, R143a/R142b, and R143a/C318 were the best candidates for accomplishing the project goals. Although the mixtures were tailored for residential heat pumps with an emphasis on capacity modulation, the screening process could be used for other refrigeration applications as well. 11 refs., 4 figs., 2 tabs.

Vineyard, E.A.; Sand, J.R.; Statt, T.G.

1989-01-01

124

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

125

Experimental investigation of moderately high temperature water source heat pump with non-azeotropic refrigerant mixtures  

Microsoft Academic Search

Experimental investigations were carried out on non-azeotropic refrigerant mixtures, named M1A (mass fraction of 20%R152a and 80%R245fa), M1B (mass fraction of 37% R152a and 63%R245fa) and M1C (mass fraction of 50%R152a and 50%R245fa), based on a water-to-water heat pump system in the condensing temperature range of 70–90°C with a cycle temperature lift of 45°C. Performance of R245fa was tested for

Shengjun Zhang; Huaixin Wang; Tao Guo

2010-01-01

126

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

127

Compatibility of refrigerants and lubricants with motor materials  

SciTech Connect

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

Doerr, R.; Kujak, S.

1992-10-01

128

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

129

Vapour-liquid equilibrium of ternary mixtures of the refrigerants R125, R143a and R134a  

Microsoft Academic Search

Apart from ternary mixtures of R32 with R125 and R134a, similar mixtures with R143a instead of R32 are discussed as alternatives to the widely used refrigerants R22 and R502. In the present work, the phase equilibrium of such ternary mixtures is described by simple cubic equations of state which are based only on experimental data for the pure substances and

M Nagel; K Bier

1996-01-01

130

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

SciTech Connect

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

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

1993-08-18

131

Investigation of HFC236EA and HFC-236FA as CFC-114 replacements in high-temperature heat pumps  

SciTech Connect

The paper discusses a thermodynamic analysis of HFC-236ea and HFC-236fa as ozone-safe CFC-114 alternatives in a vapor-compression cycle at high-temperature heat-pump conditions. The cooling capacities and the coefficients of performance (COPs) are evaluated. Parameters assessed as criteria for performance evaluation and for reliable performance were: cooling capacity; electric power input, current, and voltage; COP; compressor volumetric and isentropic efficiencies; and discharge, winding, and oil temperatures. With all three refrigerants, the compressor ran 1800 hours without failure and without indication of excessive noise or vibration.

Kazachki, G.S.; Gage, C.L.; Hendriks, R.V.; Rhodes, W.J.

1994-05-01

132

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...

133

Theoretical Consideration on the Characteristics and the Performance Evaluation for a Heat Pump Cycle of Non-azeotropic Refrigerant Mixtures  

NASA Astrophysics Data System (ADS)

The present paper treats a possibility of performance improvement and its evaluation method for a heat pump cycle of non-azeotropic refrigerant mixtures. Calculation is made for R22 + R114 and R22 + R11 mixtures under the conditions that the inlet temperature and flow rates of heat source fluids through a condenser and an evaporator of counter flow type, heat pump thermal output and FK-value (heat transfer area times average overall heat transfer coefficient) are given. It is graphically shown that the coefficient of performance (COP)h, pressures and volumetric flow rates at suction and discharge ports of a compressor depend on the FK-value and on the flow rate of heat source fluid as well as mixture composition. The characteristics of the heat pump cycle thus obtained are markedly different from those, in which the state points of the refrigerant mixture are fixed.

Fujii, Tetsu; Koyama, Shigeru; Miyara, Akio

134

An algorithmic approach towards finding better refrigerant substitutes of CFCs in terms of the second law of thermodynamics  

Microsoft Academic Search

In this study, rational efficiency (RE) and component based irreversibility ratios of a cooling system based on the second law of thermodynamics using HFC and HC based pure refrigerants, such as, R32, R125, R134a, R143a, R152a, R290, R600a and their binary and ternary mixtures, along with R12, R22 and R502 (i.e. CFCs) have been numerically calculated. The effect of temperature

Erol Arcakl?o?lu; Abdullah Çavu?o?lu; Ali Eri?en

2005-01-01

135

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

Microsoft Academic Search

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

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

2005-01-01

136

Performance of mixture refrigerant R152a\\/R125\\/R32 in domestic air-conditioner  

Microsoft Academic Search

This work reports a ternary blend R152a\\/R125\\/R32 with a mass ratio of 48\\/18\\/34 as a potential alternative to R22. A computer code has been developed with NIST REFPROP 7.0 for the comparative analysis of thermophysical properties and refrigerant performance of this new mixture and of R22. A drop-in test of this new mixture was performed in a domestic air-conditioner originally

Jiangtao Wu; Yingjie Chu; Jing Hu; Zhigang Liu

2009-01-01

137

Vapour-liquid equilibrium of ternary mixtures of the refrigerants R32, R125 and R134a  

Microsoft Academic Search

Ternary mixtures of R32, R125 and R134a of different compositions are recommended for replacing refrigerants R22 and R502. As a prerequisite for reliably calculating vapour pressure and phase equilibria of ternary mixtures within the relevant range of temperature and composition, VLE data of the three binary systems R32\\/R134a, R125\\/R134a and R32\\/R125 have been measured from ?70°C up to the critical

M Nagel; K Bier

1995-01-01

138

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

139

Alternatives for ozone-depleting refrigerants. Report for October 1991-April 1993  

SciTech Connect

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. The two compounds are: 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), a potential alternative for CFC-114; and 1,1,2,2,3-pentafluoropropane (HFC-245ca), a potential alternative for CFC-11. These two compounds have zero ozone depletion potential, low global warming potential, and thermophysical properties closely matching those of the chlorofluorocarbons (CFCs) they may replace. Limited toxicity tests to date reveal no adverse toxic effects. Flammability tests of HFC-236ea and HFC-245ca show the former to be nonflammable and the latter to be marginally flammable depending on humidity and ignition source energy. Both compounds have been shown to be thermally and hydrolytically stable, miscible with the new polyolester lubricants, and compatible with numerous construction materials commonly used in refrigeration.

Smith, N.D.; Ratanaphruks, K.

1993-01-01

140

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

SciTech Connect

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

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

1989-05-18

141

Friction and Wear Characteristics of TiN Coated Vane for the Rotary Compressor in a R410A Refrigerant©  

Microsoft Academic Search

HFC is a potential alternative refrigerant for CFC, which depletes the ozone layer. The rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed operation. R410A, an HFC refrigerant, is used in a refrigerator compressor, but its frictional characteristic is not established. In this study, the influence of R410A refrigerant on the roller-vane

OH SE-DOO; KIM JONG-WOO; LEE YOUNG-ZE

2004-01-01

142

Modelica-based modelling and simulation of dry-expansion shell-and-tube evaporators working with alternative refrigerant mixtures  

Microsoft Academic Search

A new methodology of intermediate complexity level is developed to model the dry-expansion shell and U-tube evaporators. The model has a reasonable level of accuracy and uses fundamental physical principles in a distributed parameters approach capable of detecting the complex circuit of the shell-side flow. This level of details is necessary to simulate accurately the zeotropic refrigerant mixtures evaporation. Using

Khattar Assaf; Assaad Zoughaib; Denis Clodic

2011-01-01

143

Gas Uptake Kinetics of 1,1,1,3,3,3-Hexafluoropropane (HFC-236fa) and Identification of its Potential Metabolites.  

National Technical Information Service (NTIS)

As part of the Navy's efforts to eliminate ozone depleting substances, a new refrigerant, HFC-236fa, has been developed through a joint EPA/Navy effort. This refrigerant is a replacement for refrigerant CFC-114 which is used in centrifugal chillers aboard...

A. Vinegar G. W. Buttler M. C. Caracci J. D. McCafferty

1995-01-01

144

Selection of ozone-safe, nonazeotropic refrigerant mixtures for capacity modulation in residential heat pumps  

Microsoft Academic Search

Many combinations of refrigerants have been tested in an effort to improve the efficiency of residential heat pumps. Up to this point, there has been no systematic approach for determining which fluid pairs have the greatest potential for improving heat pump performance. The primary purpose of this work was to perform a comprehensive screening of refrigerant pairs which, through a

E. A. Vineyard; J. R. Sand; T. G. Statt

1989-01-01

145

40 CFR Appendix F to Subpart B of... - Standard for Recover-Only Equipment That Extracts a Single, Specific Refrigerant Other Than CFC...  

Code of Federal Regulations, 2010 CFR

...Equipment That Extracts a Single, Specific Refrigerant Other Than CFC-12 or HFC-134a ...Equipment That Extracts a Single, Specific Refrigerant Other Than CFC-12 or HFC-134a ...recycle, any single, specific automotive refrigerant other than CFC-12 or...

2010-07-01

146

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

SciTech Connect

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

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

1992-08-01

147

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

SciTech Connect

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

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

1992-01-01

148

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

149

Solubility and viscosity of R-134a refrigerant/lubricant mixtures  

SciTech Connect

In response to concerns about the depletion of the stratospheric ozone layer, the HVAC and R industry is in the process of introducing environmentally safer refrigerants. This process is well underway. Because of the different properties of some new refrigerants (like R-134a), new lubricants are needed. There also exists a need for fundamental data on these new refrigerant/lubricant pairs. R-134a used in this work was 99.97 percent pure. The proprietary lubricant had a viscosity of 70 cs at 40{degrees} C.

Thomas, R.H.P.; Pham, H.T.; Wu, W.T. (Allied Signal Corp., Buffalo, NY (US))

1991-02-01

150

Vapor-liquid equilibria for the difluoromethane (HFC-32) + 1,1,1,2-tetrafluoroethane (HFC-134a) system  

SciTech Connect

Isothermal vapor-liquid equilibrium data of the binary mixture of difluoromethane (HFC-32) + 1,1,1,2-tetrafluoroethane (HFC-134a) have been measured in the temperature range between 263 K and 323 K. The experiment was carried out with a circulation type apparatus with the measurement of temperature, pressure, and compositions of the liquid and vapor phases. The experimental data were correlated with the Peng-Robinson and Redlich-Kwong-Soave equations of state, and comparison with literature results has been made.

Chung, E.Y.; Kim, M.S. [Seoul National Univ. (Korea, Republic of). Dept. of Mechanical Engineering

1997-11-01

151

Projecting future HFC-23 emissions  

NASA Astrophysics Data System (ADS)

A Reference Case (RC) scenario for emissions of HFC-23 from co-production during HCFC-22 manufacture over the next 25 yr is presented. Offered as a template rather than a prediction, this model projects current production practices and existing abatement frameworks to yield insights into how the atmosphere might evolve with and without additional efforts to constrain HFC-23 emissions. Assuming that no additional abatement measures are implemented, emissions for year 2035 in this Reference Case would rise to 24 ktonnes yr-1, (cf., 8.6 ktonnes yr-1 in 2009), the atmospheric abundance of HFC-23 would rise to 50 ppt, which is a 121 % increase over the 2009 observed abundance, and HFC-23 would be expected to contribute a radiative forcing of 9 mW m-2 (cf., 4 mW m-2 in 2009). Under such a scenario, the HFC-23 emission growth rate would be a continuation of the historical trend of ~0.2 ktonnes yr-2 until 2030, after which the growth is projected to quadruple as the Montreal Protocol phase-out of HCFC production for dispersive use concludes and HFC-23 thermal decomposition in the projects of the Clean Development Mechanism (CDM) comes to a scheduled end while growth in the production of HCFC-22 for feedstock use continues to climb with projected GDP growth. Two opposite variations regarding the future renewal of CDM projects are examined for their impact on projected emissions and abundance, relative to the Reference Case scenario.

Miller, B. R.; Kuijpers, L. J. M.

2011-08-01

152

Performance and Simulation of Once-Through and Separating Cycles Using Nonazeotropic Refrigerant Mixtures.  

National Technical Information Service (NTIS)

A simulation program developed at the University of Illinois at Urbana-Champaign was refined to match the performance of an experimental refrigeration facility located in the laboratory of the Department of Mechanical and Industrial Engineering in which t...

D. Boggs W. F. Stoecker

1986-01-01

153

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

SciTech Connect

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

Doerr, R.; Kujak, S.

1992-10-01

154

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...J2788âHFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

2013-07-01

155

An Experimental Investigation of Pressure Drop in Flow Boiling of Pure Refrigerants and Their Mixture in Horizontal Tube  

NASA Astrophysics Data System (ADS)

Experimental investigation of pressure drop for pure refrigerants R134a and R123 and their mixtures as test fluids was carried out for both an adiabatic and a diabatic two-phase flow in a horizontal tube. The measured frictional pressure drop in the adiabatic experiments increased in the S-shaped curve as equilibrium vapor quality was increased. These data were compared to various correlations proposed in the past for the frictional pressure drop. The homogeneous model considerally underpredicted the present data both for pure fluids and their mixtures in the entire mass flux range 150 to 600kg/m2s covered in the measurements, while Friedel correlation was found rather well to correlate the frictional pressure drop data among compared correlations. However a detailed examination showed Friedel correlation underpredicted the present data in the stratified and stratified-wavy flow regions at low vapor quality and overpredicted in the annular flow region at high quality. A new two-phase multiplier was developed from a dimensional analysis of the frictional pressure drop data measured in the adiabatic experiment. This new multiplier was found successfully to correlate the frictional pressure drop measured in the diabatic flow boiling experiments of pure refrigerants and their mixtures almost with a mean deviation of 20%.

Lim, Tae Woo; Kim, Jun Hyo

156

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...

157

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...

158

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...

159

Emissions and environmental impacts from air-conditioning and refrigeration systems  

Microsoft Academic Search

The impacts of air conditioning and refrigeration systems on stratospheric ozone are primarily linked to release of ozone-depleting refrigerants. Their contributions to global warming stem both from release of refrigerants and from emission of greenhouse gases (GHGs) for associated energy use. Because the energy-related component has a significantly higher warming impact, phaseout of hydrofluorocarbon (HFC) refrigerants with less efficient options

James M. Calm

2002-01-01

160

Computational and experimental investigation of low ODP and low GWP HCFC123 and HC290 refrigerant mixture alternate to CFC12  

Microsoft Academic Search

At the advent of the Montreal protocol, R134a has been suggested as an alternate refrigerant to R12. R134a is a high global warming potential gas and needs to be controlled as per the Kyoto protocol. It is reported that there is no single refrigerant or mixture available to satisfy both the ozone depletion potential (ODP) and global warming potential (GWP)

K. Senthil Kumar; K. Rajagopal

2007-01-01

161

Projecting future HFC-23 emissions  

NASA Astrophysics Data System (ADS)

A Reference Case (RC) scenario for emissions of HFC-23 from co-production during HCFC-22 manufacture over the next 25 years is presented. Offered as a template rather than a prediction, this model projects current production practices and existing abatement frameworks to yield insights into how atmospheric composition and radiative forcing might change with and without additional efforts to constrain HFC-23 emissions. Assuming that no additional abatement measures are implemented, emissions for year 2035 in this Reference Case would rise to 24 ktonnes yr-1, (cf., 8.6 ktonnes yr-1 in 2009), the atmospheric abundance of HFC-23 would rise to 50 ppt, which is a 121 % increase over the 2009 observed abundance, and HFC-23 would be expected to contribute a radiative forcing of 9 mW m-2 (cf., 4 mW m-2 in 2009). Under such a scenario, the HFC-23 emission growth rate would be a continuation of the historical trend of ∼0.2 ktonnes yr-2 until 2030, after which the growth is projected to quadruple as the Montreal Protocol phase-out of HCFC production for dispersive use concludes and HFC-23 thermal decomposition in the projects of the Clean Development Mechanism (CDM) comes to a scheduled end while growth in the production of HCFC-22 for feedstock use continues to climb with projected GDP growth. Two opposite variations regarding the future renewal of CDM projects are examined for their impact on projected emissions and abundance, relative to the Reference Case scenario.

Miller, B. R.; Kuijpers, L. J. M.

2011-12-01

162

Selection of Ozone-Safe, Nonazeotropic Refrigerant Mixtures for Capacity Modulation in Residential Heat Pumps.  

National Technical Information Service (NTIS)

Many combinations of refrigerants have been tested in an effort to improve the efficiency of residential heat pumps. Up to this point, there has been no systematic approach for determining which fluid pairs have the greatest potential for improving heat p...

E. A. Vineyard J. R. Sand T. G. Statt

1989-01-01

163

Alternatives for CFC-12 refrigerant in automotive air conditioning. Report for October 1996-March 1997  

SciTech Connect

Ten refrigerants including CFC-12, HFC-134a, and eight refrigerant blends were tested in an instrumented automotive air-conditioning system designed for CFC-12. The refrigerants were compared at three test conditions for refrigeration capacity, coefficient of performance, compressor discharge pressure, compressor discharge temperature, and evaporator outlet pressure. The results were obtained by testing all the refrigerants in the same system under the same conditions, and the results provide an indication of the comparative performance of the refrigerants.

Jetter, J.J.; Delafield, F.R.

1997-12-31

164

New chemical alternative for ozone-depleting substances: HFC-236fa. Final report, December 1996-April 1997  

SciTech Connect

The report gives results of a preliminary evaluation of a new hydrofluoro-carbon (HFC)--HFC-236fa or 1,1,1,3,3,3-hexafluoropropane--asa possible alternative for chlorofluorocarbon (CFC)-114 (1,2-dichloro-1, 1,2,2-tetrafluoroethane) refrigerant for chillers and asa possible fire suppressant replacement for halon-1301 (bromotrifluoromethane). Evaluation tests included an examination of flammability, stability, atmospheric lifetime, thermophysical properties, lubricant miscibility and solubility, materials compatibility, inhalation toxicity, refrigerant performance, heat transfer characteristics, and flame suppression.

Smith, N.D.; Brna, T.G.; Gage, C.L.; Hendriks, R.V.

1997-07-01

165

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

166

Relative permittivity measurements of 1,1,1,2-tetrafluoroethane (HFC 134a), pentafluoroethane (HFC 125), and difluoromethane (HFC 32)  

SciTech Connect

The relative permittivity of HFC 134a, HFC 32, and HFC 125 was measured as a function of temperature and pressure, to cover the liquid and gaseous states. The temperature range studied was 303 to 403 K, and the pressure range was 4.0 to 30.0 MPa. The relative permittivity, {epsilon}, could be fitted to the reduced density {rho}{sub r} using the function ({epsilon} {minus} 1)/(2{epsilon} + 1). The dipole moment of HFC 134 a in the liquid phase has been calculated.

Abbott, A.P.; Eardley, C.A.; Tooth, R. [Leicester Univ. (United Kingdom). Chemistry Dept.

1999-01-01

167

Evaluation of Ikon-12 (trade name) refrigerant for motor vehicle air conditioning. Report for October 1995-June 1996  

SciTech Connect

The paper gives results of an evaluation of a proprietary refrigerant, Ikon-12, as an alternative to hydrofluorocarbon (HFC)-134a for automotive air conditioning. In preliminary tests, Ikon-12 was found to be compatible with a polyolester lubricant and engineering materials. Refrigeration capacity and efficiency for Ikon-12 compared favorably to those for HFC-134a. In a preliminary durability test, Ikon-12 refrigerant showed no significant chemical breakdown after extended operation with an elevated compresssor discharge temperature.

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

1997-09-01

168

Evaluation of Ikon-12 (trade name) refrigerant for motor vehicle air conditioning. Report for October 1995June 1996  

Microsoft Academic Search

The paper gives results of an evaluation of a proprietary refrigerant, Ikon-12, as an alternative to hydrofluorocarbon (HFC)-134a for automotive air conditioning. In preliminary tests, Ikon-12 was found to be compatible with a polyolester lubricant and engineering materials. Refrigeration capacity and efficiency for Ikon-12 compared favorably to those for HFC-134a. In a preliminary durability test, Ikon-12 refrigerant showed no significant

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

1997-01-01

169

Solubility of Blowing Agents HCFC 142b, HFC 134a, HFC 125 and Isopropanol in Polystyrene  

Microsoft Academic Search

The vapor-liquid equilibria of HCFC 142b, HFC 134a, HFC 125 and isopropanol in polystyrene were determined in a closed high pressure vessel at temperatures up to 220°C. Complete solubility maps are presented for each blowing agent, including conditions for phase separation in the polystyrene phase. In order of decreasing solubility, the blowing agents rank isopropanol > HCFC 142b > HFC

Louis E. Daigneault; Y. Paul Handa; Betty Wong; Louis M. Caron

1998-01-01

170

Retrofitting an automotive air conditioner with HFC-134a, additive, and mineral oil. Final report, October 1992-May 1994  

SciTech Connect

The paper gives results of an evaluation of a lubricant additive developed for use in retrofitting motor vehicle air conditioners. The additive was designed to enable HFC-134a to be used as a retrofit refrigerant with the existing mineral oil in CFC-12 systems. The goal of the project was to provide preliminary feasibility testing of the additive. The cooling effect of the test system retrofitted with HFC-134a and the oil additive was nearly the same as that of the original system with CFC 12 refrigerant. If lubricant additives prove to be successful, miscible lubricants may not be needed for retrofitting some automotive systems. The retrofitting procedure might be simplified and the cost to consumers might be reduced. It has not been determined if retrofitting systems with HFC-134a and oil additives is feasible for a wider range of operating conditions and types of equipment, including the applicability of orifice tube/suction accumulator systems.

Jetter, J.J.; Delafield, F.R.

1994-05-01

171

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

PubMed

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

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

2012-11-20

172

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.

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

2009-01-01

173

Proceedings of the 1993 Non-Fluorocarbon Insulation, Refrigeration and Air Conditioning Technology Workshop  

NASA Astrophysics Data System (ADS)

Sessions included: HFC blown polyurethanes, carbon dioxide blown foam and extruded polystyrenes, plastic foam insulations, evacuated panel insulation, refrigeration and air conditioning, absorption and adsorption and stirling cycle refrigeration, innovative cooling technologies, and natural refrigerants. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

174

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

Microsoft Academic Search

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

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

2006-01-01

175

Choked flow mechanism of HFC134a flowing through short-tube orifices  

Microsoft Academic Search

This paper is a continuation of the author’s previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406mm to 0.686mm with lengths ranging from 1mm to 3mm which can be applied to a miniature vapour-compression refrigeration system

Kitti Nilpueng; Somchai Wongwises

2011-01-01

176

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

NASA Astrophysics Data System (ADS)

We report on ground-based atmospheric measurements and emission estimates of the four anthropogenic hydrofluorocarbons (HFCs) HFC-365mfc (CH3CF2CH2CF3, 1,1,1,3,3-pentafluorobutane), HFC-245fa (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane), HFC-227ea (CF3CHFCF3, 1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (CF3CH2CF3, 1,1,1,3,3,3-hexafluoropropane). In situ measurements are from the global monitoring sites of the Advanced Global Atmospheric Gases Experiment (AGAGE), the System for Observations of Halogenated Greenhouse Gases in Europe (SOGE), and Gosan (South Korea). We include the first halocarbon flask sample measurements from the Antarctic research stations King Sejong and Troll. We also present measurements of archived air samples from both hemispheres back to the 1970s. We use a two-dimensional atmospheric transport model to simulate global atmospheric abundances and to estimate global emissions. HFC-365mfc and HFC-245fa first appeared in the atmosphere only ˜1 decade ago; they have grown rapidly to globally averaged dry air mole fractions of 0.53 ppt (in parts per trillion, 10-12) and 1.1 ppt, respectively, by the end of 2010. In contrast, HFC-227ea first appeared in the global atmosphere in the 1980s and has since grown to ˜0.58 ppt. We report the first measurements of HFC-236fa in the atmosphere. This long-lived compound was present in the atmosphere at only 0.074 ppt in 2010. All four substances exhibit yearly growth rates of >8% yr-1 at the end of 2010. We find rapidly increasing emissions for the foam-blowing compounds HFC-365mfc and HFC-245fa starting in ˜2002. After peaking in 2006 (HFC-365mfc: 3.2 kt yr-1, HFC-245fa: 6.5 kt yr-1), emissions began to decline. Our results for these two compounds suggest that recent estimates from long-term projections (to the late 21st century) have strongly overestimated emissions for the early years of the projections (˜2005-2010). Global HFC-227ea and HFC-236fa emissions have grown to average values of 2.4 kt yr-1 and 0.18 kt yr-1 over the 2008-2010 period, respectively.

Vollmer, Martin K.; Miller, Benjamin R.; Rigby, Matthew; Reimann, Stefan; Mühle, Jens; Krummel, Paul B.; O'Doherty, Simon; Kim, Jooil; Rhee, Tae Siek; Weiss, Ray F.; Fraser, Paul J.; Simmonds, Peter G.; Salameh, Peter K.; Harth, Christina M.; Wang, Ray H. J.; Steele, L. Paul; Young, Dickon; Lunder, Chris R.; Hermansen, Ove; Ivy, Diane; Arnold, Tim; Schmidbauer, Norbert; Kim, Kyung-Ryul; Greally, Brian R.; Hill, Matthias; Leist, Michael; Wenger, Angelina; Prinn, Ronald G.

2011-04-01

177

The performance of a residential heat pump operating with a nonazeotropic binary refrigerant mixture  

NASA Astrophysics Data System (ADS)

Results of laboratory measurement of the performance change of a substantially unmodified residential heat pump designed for 222 when charged with a non azeotropic, binary mixture of R1381 and R152a is presented. Results are presented for various sizes of fixed expansion devices. The effect of gliding temperature in the saturation zone was found to be small. The effect of compositions shift by flash distillation in the accumulator was found to measurably improve low temperature heating performance. It was further observed that some system modification (such as the addition of a receiver) could have further enhanced this low temperature heating performance improvement.

Didion, D.; Mulroy, W.

178

Thermodynamic and transport properties of some alternative ozone-safe refrigerants for industrial refrigeration equipment: Study in Belarus and Ukraine  

SciTech Connect

The study of several hydrofluorocarbons (HFC) and fluorocarbons (FC) and their binary mixtures that have no ozone-depleting ability is being carried out in the framework of Belarus National program. The fluids include HFCs R134a, R152a, R125, and R32, and FC R218. The following properties are being investigated: (1) phase equilibrium parameters including the boiling and condensing curve and critical point, thermophysical properties at these parameters, and heat of evaporation; (2) isobaric and isochoric heat capacity, ethalpy, and entropy in the gas and liquid state; (3) speed of sound, thermal conductivity, viscosity, and density in the gas and liquid state; (4) dielectric properties and surface tension; (5) behavior of combined construction materials inside the refrigerant medium; and (6) solubility in compressor oils and other technological characteristics. The series of results obtained by authors during the period 1990-1993 is presented.

Grebenkov, A.J.; Klepatsky, P.M.; Beljajeva, O.V. [Inst. of Power Engineering Problems, Minsk (Belgium)] [and others

1996-05-01

179

Transport properties of refrigerants R32, R125, R134a, and R125+R32 mixtures in and beyond the critical region  

Microsoft Academic Search

A practical representation for the transport coefficients of pure refrigerants R32, R125, R134a, and R125+R32 mixtures is presented which is valid in the vapor–liquid critical region. The crossover expressions for the transport coefficients incorporate scaling laws near the critical point and are transformed to regular background values far away from the critical point. The regular background parts of the transport

S. B Kiselev; R. A Perkins; M. L Huber

1999-01-01

180

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

National Technical Information Service (NTIS)

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. ...

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

1992-01-01

181

Viscosity modeling of several HFC refrigerants using the friction theory  

Microsoft Academic Search

The viscosity models of pentafluoroethane (R125), 1,1-difluoroethane (R152a), 1,1,1,2-tetrafluoroethane (R134a), difluoromethane (R32), and 1,1,1-trifluoroethane (R143a) have been correlated using the friction theory in conjunction with the Span–Wagner equation of state and Sato et al. equation of state. The obtained viscosity models cover a wide range of fluids states, including the supercritical region. And the models can represent the viscosities of

Xiaopo Wang; Jiangtao Wu; Zhigang Liu

2007-01-01

182

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

183

Manufacture of refrigeration oils  

Microsoft Academic Search

Lubricating oils suitable for use in refrigeration equipment in admixture with fluorinated hydrocarbon refrigerants are produced by solvent extraction of naphthenic lubricating oil base stocks, cooling the resulting extract mixture, optionally with the addition of a solvent modifier, to form a secondary raffinate and a secondary extract, and recovering a dewaxed oil fraction of lowered pour point from the secondary

R. P. Chesluk; H. J. Platte; A. J. Sequeira

1981-01-01

184

High temperature hot water heat pump with non-azeotropic refrigerant mixture HCFC22\\/HCFC141b  

Microsoft Academic Search

A water-to-water high temperature heat pump was studied experimentally. The performance of the system was characterized by refrigerant compositions, compressor RPM and water temperature change. For the experimental conditions of the inlet water temperature of evaporator of 40 °C and the inlet and outlet water temperatures of the condenser of 70 and 80 °C, respectively, the experiment shows that the

T. X. Li; K. H. Guo; R. Z. Wang

2002-01-01

185

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

186

Vapor–Liquid Equilibria of Alternative Refrigerants by Molecular Dynamics Simulations  

Microsoft Academic Search

Alternative refrigerants HFC-152a (CHF2CH3), HFC-143a (CF3CH3), HFC-134a (CF3CH2F), and HCFC-142b (CF2ClCH3) are modeled as a dipolar two-center Lennard–Jones fluid. Potential parameters of the model are fitted to the critical temperature and vapor–liquid equilibrium data. The required vapor–liquid equilibrium data of the model fluid are computed by the Gibbs–Duhem integration for molecular elongations L=0.505 and 0.67, and dipole moments µ*2=0, 2,

M. Lísal; R. Budinský; V. Vacek; K. Aim

1999-01-01

187

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

Microsoft Academic Search

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

Christophe Coquelet; Dominique Richon

2007-01-01

188

Two-phase frictional pressure drop of R-134a and R-410A refrigerant-oil mixtures in straight tubes and U-type wavy tubes  

SciTech Connect

This study presents single-phase and two-phase pressure drop data for R-134a/oil mixture flowing in a wavy tube with inner diameter of D=5.07mm and curvature ratio 2R/D=5.18 and R-410A/oil mixture flowing in a wavy tube of D=3.25mm and 2R/D=3.91. Both mixtures have oil concentration C=0%, 1%, 3% and 5% for the tests. The ratio of frictional factor between U-bend in wavy tube and straight tube (f{sub C}/f{sub S}) is about 3.5 for Re<2500 and is approximate 2.5 for Re=3500-25,000 for oil and liquid R-134a mixture flowing in the 5.07mm diameter wavy tube. The influence of oil concentration on single-phase friction factor is negligible, provided that the properties are based on the mixture of lubricant and refrigerant. The ratio between two-phase pressure gradients of U-bend and straight tube is about 2.5-3.5. This ratio is increased with oil concentration and vapor quality. The influence of oil is augmented at a higher mass flux for liquid spreading around the periphery at an annular flow pattern. Moreover, the influence of lubricant becomes more evident of a U-bend configuration. This is associated the induced swirled flow motion and an early change of flow pattern from stratified to annular flow pattern. The frictional two-phase multiplier for straight tube can be fairly correlated by using the Chisholm correlation for the data having Martinelli parameter X between 0.05 and 1.0. Fridel correlation also shows a good agreement with a mean deviation of 17.6% to all the straight tube data. For the two-phase pressure drop in U-bend, the revised Geary correlation agrees very well with the R-134a and R-410A oil-refrigerant data with a mean deviation of 16.4%. (author)

Chen, Ing Youn; Wu, Yu-Shi [Mechanical Engineering Department, National Yunlin University of Science and Technology, Yunlin 640 (Taiwan); Chang, Yu-Juei; Wang, Chi-Chuan [Energy and Resource Laboratories, Industrial Technology Research Institute Hsinchu 310 (Taiwan)

2007-02-15

189

Effect of Fin Geometry on Condensation of Zeotropic Refrigerant Mixture R407C in a Staggered Bundle of Horizontal Finned Tubes  

NASA Astrophysics Data System (ADS)

Row-by-row heat transfer data were obtained during condensation of downward-flowing refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two kinds of conventional low-fin tubes with flat-sided annular fins and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m2s, and the condensation temperature difference from 1.5 to 12 K. At a low to medium film Reynolds number(<2000), the highest heat transfer coefficient was obtained by one of the three-dimensional fin tubes. At a high film Reynolds number(>2000), on the other hand, the highest performance was obtained by one of the low-fin tubes. For all tubes tested, the heat transfer coefficient decreased with decreasing mass velocity. On the basis of previous results for R134a, consideration was given to the characteristics of vapor phase mass transfer of R407C.

Honda, Hiroshi; Takata, Nobuo; Takamatsu, Hiroshi; Kim, Jeongsik; Usami, Keiichiro

190

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy.  

PubMed

The aim of this study was the quantification of vapors of the ozone-depleting refrigerant R22 in the presence of its most important substitute R134a, by the use of the reflectometric interference spectroscopy and polymers as sensitive layers. First, the sorption characteristic of different types of polymers exposed to the vapors of the two analytes was investigated. Then, binary mixtures of the two refrigerants were measured with an array set-up on the basis of six polymer sensors. The measurements were evaluated by the use of neural networks, whereby low limits of detection of 0.45 percentage volume (vol. %)for R22 and 1.45 vol. % for R134a could be established. Additionally, one polar polymer and one microporous polymer were selected for the measurements with a low-cost set-up. The quantification of R22 in the presence of R134a with this low-cost set-up was possible with a limit of detection of 0.44 vol. %, which would enable a fast and economical monitoring at recycling stations. PMID:12434242

Dieterle, F; Belge, G; Betsch, C; Gauglitz, G

2002-10-08

191

Refrigeration and thermometry of liquid {sup 3}He-{sup 4}He mixtures in the ballistic regime  

SciTech Connect

The ballistic regime of liquid {sup 3}He-{sup 4}He mixtures is characterized by a large mean free path {lambda} 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 superfluid {sup 3}He 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 superfluid {sup 3}He-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 {mu}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.

Koenig, R.; Betat, A.; Pobell, F. [Universitaet Bayreuth (Germany)

1994-11-01

192

Overview of CFC replacement issues for household refrigeration  

SciTech Connect

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

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

1991-12-31

193

Overview of CFC replacement issues for household refrigeration  

SciTech Connect

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

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

1991-01-01

194

Overview of CFC replacement issues for household refrigeration  

NASA Astrophysics Data System (ADS)

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

Vineyard, E. A.; Roke, L.; Hallett, F.

195

Thermodynamic Properties of HFC227ea  

Microsoft Academic Search

The density and speed of sound in gaseous and liquid 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) have been studied by a ?-attenuation technique, an ultrasonic interferometer, and an isochoric piezometer method over the temperature range of 273 to 383?K at pressures up to 3.5?MPa. The purity of the samples used throughout the measurements are 99.99?mol%. The pressures of the saturated vapor were measured over

V. A. Gruzdev; R. A. Khairulin; S. G. Komarov; S. V. Stankus

2002-01-01

196

Gas absorber and refrigeration system using same  

SciTech Connect

A refrigeration system is described comprising: (a) a separator for separating a refrigerant gas from a refrigerant-rich solution to produce a refrigerant-lean solution; (b) a condenser for emitting heat to thereby condense the refrigerant gas received from the separator and an evaporator for absorbing heat to thereby evaporate the condensed refrigerant gas; (c) an absorber assembly including: a precooler for precooling the refrigerant-lean solution received from the separator; a mixer for mixing the refrigerant gas from the evaporator with the precooled refrigerant-lean solution received form the precooler to thereby form a gas-solution mixture, the mixer having nozzles for allowing the refrigerant-lean solution to be injected there through into a flow of the gas-solution mixture, the nozzles being adapted to cause the refrigerant-lean solution to experience a predetermined pressure drop there across; and absorbent tubes for allowing the gas-solution mixture to flow there through while causing the refrigerant-lean solution to absorb the refrigerant gas to thereby generate a refrigerant-rich solution; (d) a solution receiver for receiving the refrigerant-rich solution through the absorber tubes and a manifold for containing an overflow through the absorber tubes during a normal operation of the refrigeration system, an upper part of the solution receiver serving to contain the refrigerant gas; (e) recycling means for controllably recycling the refrigerant gas from the solution receiver into the absorber assembly; and a solution pump for delivering the refrigerant-rich solution from the solution receiver to the separator through a generator for heating the refrigerant-rich solution.

Dehne, H.

1993-08-24

197

Performance of a residential heat pump operating with a non-azeotropic binary refrigerant mixture - an interim report. [R22 vs non-azeotropic binary mixture of R13B1 and R152a  

SciTech Connect

This report presents results of laboratory measurement of the performance change of a substantially unmodified residential heat pump designed for R22 when charged with a non-azeotropic, binary mixture of R13B1 and R152a. Results are presented for various sizes of fixed expansion devices. The effect of gliding temperature in the saturation zone was found to be small. The effect of composition shift by flash distillation in the accumulator was found to measurably improve low temperature heating performance. There appears to be an inherent trade-off when operating an unmodified heat pump with mixtures so as to increase capacity at lower temperatures. This trade-off is that as the evaporator pressure decreases and refrigerant begins to flood through to the accumulator and thus allowing the composition shift to occur, the subcooling on the high pressure side also decreases causing a decrease in the available latent enthalpy difference. A possible solution to this problem might be to increase the amount of initial charge. This would cause on increase in head pressures which could be a problem in the cooling mode. A possible solution to this excessive head pressure problem would be to incorporate a receiver in the system in the branch line just ahead of the expansion device for the outdoor coil. Thus, when this coil is acting as an evaporator (i.e., heating mode) the stored refrigerant would be released into the circulating system allowing for more composition shift to occur. Such a solution will be pursued as one of the items of study during the next phase of this project. 9 refs., 11 figs., 1 tab.

Didion, D.; Mulroy, W.

1984-01-01

198

Condensing Heat Transfer Characteristics of HFC-134a and CFC-12 Inside a Smooth Tube in Low Mass Velocity Range  

NASA Astrophysics Data System (ADS)

Condensing heat transfer coefficients of HFC-134a and CFC-12 were measured inside a horizontal and a vertical smooth tub with an inner diameter of 4.35mm. The mass velocity of refrigerant ranged from 60 to 170 kg/(m2s) and the saturation temperature was about 450°C. The results obtained are as follows ; (1) According to the difference in flow directions, condensing heat transfer coefficients in low mass velocity range (below 100 kg / (m2s)) were ranked as follows ; horizontal›vertical upward›vertical downward. (2) Condensing heat transfer coefficient of HFC-134a was 15-20% higher than that of CFC-12 with both horizontal and vertical tubes.

Itoh, Masaaki; Kobayashi, Chie; Hara, Toshitugu; Shibayama, Masayuki; Kunugi, Yoshifumi

199

A numerical investigation of a diffusion-absorption refrigeration cycle based on R124DMAC mixture for solar cooling  

Microsoft Academic Search

Research on new working fluid for uses in absorption systems has been continued. The feasibility of a solar driven DAR using the mixture R124\\/DMAC as working fluid is investigated by numerical simulation. The cycle is simulated for two cooling medium temperatures, 27°C and 35°C, and four driving heat temperatures in the range [90°C–180°C]. The performance characteristics of this system is

N. Ben Ezzine; R. Garma; A. Bellagi

2010-01-01

200

Physical properties of fluorinated propane and butane derivatives as alternative refrigerants  

SciTech Connect

The paper presents physical property measurements for 24 fluorinated propane and butane derivatives and one fluorinated ether which include melting point, boiling point, vapor pressure below the boiling point, heat of vaporization at the boiling point, critical properties (temperature and density), and liquid-phase heat capacities at 40 C. Measured vapor pressures are reported to the critical temperature for four of the compounds: HFC-227ea, HFC-245cb, HFC-236ea, and HFE-125a. These measured data, combined with estimated vapor-phase densities, heat capacities, and vapor pressures, may be used to evaluate the potentials of these chemicals as alternative refrigerants. Modified corresponding states methods, using HFC-134a as a reference fluid, are presented as a way to obtain the needed estimated data, and the accuracy of these methods is judged by comparisons with measured data.

Beyerlein, A.; DesMarteau, D.; Hwang, S.; Smith, N.; Joyner, P.

1993-01-01

201

Thermodynamic properties of HFC338mccq, CFâCFâCFâCHâF, 1,1,1,2,2,3,3,4-octafluorobutane  

Microsoft Academic Search

The authors report the thermodynamic properties of 1,1,1,2,2,3,3,4-octafluorobutane, which has been designated as HFC-338mccq by the refrigeration industry. The measurements span the temperature and pressure ranges encountered in thermal machinery. The properties measured include the vapor pressure, the density of the compressed liquid, the refractive index of both the saturated liquid and the saturated vapor, the critical temperature, the capillary

D. R. Defibaugh; E. Carrillo-Nava; J. J. Hurly; M. R. Moldover; J. W. Schmidt; L. A. Weber

1997-01-01

202

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

NASA Astrophysics Data System (ADS)

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

Friedmann, Gideon

203

Refrigerant poisoning  

MedlinePLUS

A refrigerant is a chemical that makes things cold. This article discusses poisoning from sniffing or swallowing such chemicals. ... occurs when people intentionally sniff a type of refrigerant called freon. This is for information only and ...

204

Thermoacoustic Refrigeration.  

National Technical Information Service (NTIS)

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 oper...

S. L. Garrett T. J. Hofler

1991-01-01

205

INVESTIGATION OF HFC-236EA AND HFC-236FA AS CFC-114 REPLACEMENTS IN HIGH-TEMPERATURE HEAT PUMPS  

EPA Science Inventory

The paper discusses a thermodynamic analysis of HFC-236ea and HFC-236f as ozone-safe CFC-114 alternatives in a vapor-compression cycle at high-temperature heat-pump conditions. he cooling capacities and the coefficients of performance (COPs) are evaluated. omprehensive calorimete...

206

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

207

Isochoric Heat Capacity Measurements for Binary Refrigerant Mixtures Containing Difluoromethane (R32), Pentafluoroethane (R125), 1,1,1,2-Tetrafluoroethane (R134a), and Trifluoroethane (R143a) from 200 to 345 K at Pressures to 35 MPa  

Microsoft Academic Search

Molar heat capacities at constant volume Cv were measured for binary refrigerant mixtures with an adiabatic calorimeter with gravimetric determinations of the amount of substance. Temperatures ranged from 200 to 345 K, while pressures extended up to 35 MPa. Measurements were conducted on liquid samples with equimolar compositions for the following binary systems: R32\\/R134a, R32\\/R125, R125\\/R134a, and R125\\/R143a. The uncertainty

J. W. Magee

2000-01-01

208

Isochoric p–?–T and Heat Capacity Cv Measurements for Ternary Refrigerant Mixtures Containing Difluoromethane (R32), Pentafluoroethane (R125), and 1,1,1,2-Tetrafluoroethane (R134a) from 200 to 400 K at Pressures to 35 MPa  

Microsoft Academic Search

The p–?–T relationships and constant volume heat capacity Cv were measured for ternary refrigerant mixtures by isochoric methods with gravimetric determinations of the amount of substance. Temperatures ranged from 200 to 400 K for p–?–T and from 203 to 345 K for Cv, while for both data types pressures extended to 35 MPa. Measurements of p–?–T were carried out on

J. W. Magee

2000-01-01

209

Refrigeration - Principles of Mechanical Refrigeration.  

National Technical Information Service (NTIS)

Shows the application of basic physics of heat transfer in refrigeration units. Explains how temperature changes in refrigerant passes through the expanision valve, compressor, condensor, and evaporator as it carries heat to the outside air.

1994-01-01

210

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

211

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

SciTech Connect

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

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

1994-08-01

212

Experiment on Flow Boiling of HFC134a in a Multi-port Extruded Tube  

NASA Astrophysics Data System (ADS)

In the present study, the local heat transfer and pressure drop characteristics are investigated experimentally for the flow boiling of refrigerant HFC134a in a multi-port extruded tube of 1.06mm in hydraulic diameter. The test tube is 865mm in total length made of aluminum. The pressure drop was measured at an interval of 191mm, the local heat transfer coefficient was measured in every subsection of 75mm in effective heating length. The measured pressure drop was compared with a few correlations. Those data agree with the correlation of Koyama et al., proposed for condensation process, and of Friedel. The local heat transfer coefficients were also compared with correlation of Yu et al. It is pointed out that multiplier of the convection term in a rectangular channel is different from that of circular tube.

Kuwahara, Ken; Koyama, Shigeru; Kazari, Kengo; Nakahita, Kouichi

213

Incidence of Clostridium perfringens in commercially produced cured raw meat product mixtures and behavior in cooked products during chilling and refrigerated storage.  

PubMed

A total of 445 whole-muscle and ground or emulsified raw pork, beef, and chicken product mixtures acquired from industry sources were monitored over a 10-month period for vegetative and spore forms of Clostridium perfringens. Black colonies that formed on Shahidi-Ferguson perfringens (SFP) agar after 24 h at 37 degrees C were considered presumptive positive. Samples that were positive after a 15-min heat shock at 75 degrees C were considered presumptive positive for spores. Of 194 cured whole-muscle samples, 1.6% were positive; spores were not detected from those samples. Populations of vegetative cells did not exceed 1.70 log10 CFU/g and averaged 1.56 log10 CFU/g. Of 152 cured ground or emulsified samples, 48.7% were positive, and 5.3% were positive for spores. Populations of vegetative cells did not exceed 2.72 log10 CFU/g and averaged 1.98 log10 CFU/g; spores did not exceed 2.00 log10 CFU/g and averaged 1.56 log10 CFU/g. Raw bologna (70% chicken), chunked ham with emulsion, and whole-muscle ham product mixtures were inoculated with C. perfringens spores (ATCC 12916, ATCC 3624, FD1041, and two product isolates) to ca. 3.0 log10 CFU/g before being subjected either to thermal processes mimicking cooking and chilling regimes determined by in-plant temperature probing or to cooking and extended chilling regimes. Populations of C. perfringens were recovered on SFP from each product at the peak cook temperatures, at 54.4, 26.7, and 7.2 degrees C, and after up to 14 days of storage under vacuum at 4.4 degrees C. In each product, populations remained relatively unchanged during chilling from 54.4 to 7.2 degrees C and declined slightly during refrigerated storage. These findings indicate processed meat products cured with sodium nitrite are not at risk for the growth of C. perfringens during extended chilling and cold storage. PMID:12540184

Taormina, Peter J; Bartholomew, Gene W; Dorsa, Warren J

2003-01-01

214

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

215

High frequency thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

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

Symko, Orest G.

1994-06-01

216

A recuperative superfluid stirling refrigerator  

SciTech Connect

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

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

1993-07-01

217

Alternative Drop-in Refrigerant to R22 for Refrigerating System of Refrigerated Warehouse  

NASA Astrophysics Data System (ADS)

We tested to use several compositions of a four-component-mixture R 32/125/134a/600 as a refrigerant for replacing R 22 in refrigeration system of refrigerated warehouses. R 32, R 125, and R 134a are hydrofluorocarbons and R 600 is normal butane. The refrigeration system designed for R 22 can be used without any change or with very minor change. By using appropriate composition of the four-component refrigerant, existing refrigeration system can provide best performance because the adjusted properties of the refrigerant can somewhat compensate for the individual hardware problems. Practical operation test was done by using a refrigeration system of nominal cooling capacity of 30.2 kW with a 22 kW two-stage compressor which equipped for an 858m3 refrigerated warehouse maintaining at -30°C. The pressure condition and the coefficient of performance of R 32/125/134a/600 are similar to R 22 from a theoretical viewpoint. The power consumption of R 32/125/134a/600 was small enough or not to be worse than that of R22, which was confirmed from the actual test results.

Bandoh, Yuriko; Furuyama, Kyoko; Saito, Motomu; Sato, Haruki; Morimoto, Masanori; Iwasaki, Minoru; Tonouchi, Takashi; Kotani, Yasuhisa

218

Heat transfer during condensation of HFC-134a and R-404A inside of a horizontal smooth and micro-fin tube  

SciTech Connect

In recent small and medium capacity refrigeration systems, the condenser tubes are provided with micro-fins from inside. The vapour refrigerant at the compressor outlet and the condenser inlet is in superheat state. As it advances in the condenser it is in two phases and at the outlet it is in sub cooled liquid. The heat transfer coefficient (HTC) during condensation of HFC-134a and R-404A in a smooth (8.56 mm ID) and micro-fin tubes (8.96 mm ID) are experimentally investigated. Different from previous studies, the present experiments are performed for various condensing temperatures, with superheating and sub cooling and using hermetically sealed compressor. The test runs are done at average saturated condensing temperatures ranging from 35 C to 60 C. The mass fluxes are between 90 and 800 kg m{sup -2} s{sup -1}. The experimental results indicate that the average HTC increases with mass flux but decreases with increasing condensing temperature for both smooth and micro-fin tubes. The average condensation HTCs of HFC-134a and R-404A for the micro-fin tubes were 1.5-2.5 and 1.3-2 times larger than that in smooth tube respectively. The HTCs for R-404A are less than that of HFC-134a. New correlations based on the data gathered during the experimentation for predicting condensation HTCs are proposed for wide range of operating conditions. (author)

Sapali, S.N. [Govt. College of Engineering, Department of Mechanical Engineering, Shivaji Nagar, Pune, Maharashtra 411 005 (India); Patil, Pradeep A. [AISSMS College of Engineering, Pune University, Mechanical Engineering Department, Kennedy Road, Near R.T.O., Pune, Maharashtra 411 001 (India)

2010-11-15

219

Vapor-liquid equilibria for the difluoromethane (HFC-32) + 1,1,1-trifluoroethane (HFC-143a) system  

SciTech Connect

Isothermal vapor-liquid equilibrium data of the binary system of difluoromethane (HFC-32) + 1,1,1-trifluoroethane (HFC-143a) were obtained in the temperature range from 263.15 K to 313.15 K. Temperature, pressure, and compositions of the liquid and vapor phases were measured with a circulation type apparatus. The experimental data were correlated with the Canahan-Starling-De Santis, Peng-Robinson, and Redlich-Kwong-Soave equations of state.

Kim, C.N.; Park, Y.M.

2000-02-01

220

Securing confidentiality in PON and HFC networks  

NASA Astrophysics Data System (ADS)

In Some kind of networks like PON (Passive Optical Networks) and HFC (Hybrid Fiber Coaxial) networks, the information from the central station (headend) to the terminals is broadcast to all of them. So each one of them besides its own data gets also the data destined for the others. Under these conditions privacy and confidentiality do not exist. The usual way to overcome this drawback is conventional encryption of the data between headend and terminals. This method besides making the communication procedure more complex, has also the drawback that traffic data cannot be protected, since the destination field of each cell cannot be encrypted. Here another method is presented which, although not encryption in the conventional meaning of the term, secures a high degree of individuality and confidentiality. The basic idea is to use different multiplexing patterns for each connection so that each terminal can demultiplex only its own data. The method is suited for the high data speed of the PON networks and maybe preferable to conventional encryption.

Koulouris, John; Koulouris, A.

1998-09-01

221

Prediction of Thermodynamic Properties of Alternative Refrigerants  

NASA Astrophysics Data System (ADS)

The use of refrigerant mixtures for R22 alternative has recently been attracted in refrigerating and air conditioning industry. However, there has not been enough information about thermodynamic properties required to analyse the properties of mixtures. In this paper, stressing the adaptability of the modified van der Waals equation of state for refrigerant mixtures, the prediction methods of thermodynamic properties for the a1ternative refrigerant and mixture are explained. Seven generalized equations of state are chosen for the subjects of discussion. Data on R32,R125,R134a and their mixtures are applied to discuss the adaptability of these equations. Resu1ts of calculation using these equations are compared with available experimental and reference data. The optimum binary interaction parameters for those equations of state are a1so presented.

Fukushima, Masato

222

Refrigeration Showcases.  

National Technical Information Service (NTIS)

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 ...

1997-01-01

223

Refrigerator Thermometers:  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... below; the freezer should be at 0 °F. Since few refrigerator controls show actual ... Also, keep in mind that your car is probably even hotter than typical ... More results from www.fda.gov/downloads/food/resourcesforyou

224

Thermodynamic properties for the alternative refrigerants  

Microsoft Academic Search

Models commonly used to calculate the thermodynamic properties of refrigerants are summarized. For pure refrigerants, the virial, cubic, Martin-Hou, Benedict-Webb-Rubin, and Helmholtz energy equations of state and the extended corresponding states model are discussed. High-accuracy formulations for 16 refrigerants are recommended. These models may be extended to mixtures through the use of mixing rules applied either to the parameters of

Mark O McLinden; Eric W Lemmon; Richard T Jacobsen

1998-01-01

225

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

SciTech Connect

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

Vineyard, E.A.

1987-01-01

226

Atmospheric lifetime and global warming potential of HFC245fa  

Microsoft Academic Search

We describe the method used to compute the global warming potential of hydrofluorocarbon (HFC) 245fa (CHF2CH2CF3). The Atmospheric and Environmental Research (AER) two-dimensional (latitude-height) chemistry-transport model was used to calculate the atmospheric lifetime and atmospheric scale height of HFC-245fa. Assuming that reaction with OH is the only removal mechanism, the recommended rate constant from Jet Propulsion Laboratory [1997] (6.1×10-13exp(-1330\\/T)cm-3s-1) implies

Malcolm Ko; Run-Lie Shia; Nien-Dak Sze; Hillel Magid; Robert G. Bray

1999-01-01

227

Aging of polyurethane foam insulation in simulated refrigerator walls  

SciTech Connect

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

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

1997-10-01

228

Recent Refrigeration Cycle Technologies for Household Refrigerators  

NASA Astrophysics Data System (ADS)

The household refrigerator is one of the most important and the biggest energy-consuming home appliances. This paper summarize recent refrigeration cycle developments in the field of domestic household refrigerators based on a survey of publications.

Nagatomo, Shigemi

229

Compatibility of refrigerants and lubricants with engineering plastics. Final report  

SciTech Connect

23 plastics have been subjected to immersion studies using 7 different lubricants at 60 C and 100 C, and 10 different refrigerants at ambient and 60 C. In the first part of the study, 22 hermetic stress crack-creep rupture test chambers were used to determine dynamic effects of a constant dead weight load on plastic test bars immersed at 20 C in a 40% refrigerant 32 ISOVG branched acid polyolester lubricant. The creep modulus data of the 10 refrigerants, using a dead weight load of 25% of ultimate tensile, are compared to values for air and HCFC-22. In the second part, the plastic test bars were aged for 14 d at constant refrigerant pressure 300 psia with 17 refrigerant lubricant combinations at 150 C. Additional evaluations were conducted to elucidate the effects of temperature, refrigerant, and lubricant on the plastics. At 150 C, high acid formation (high TAN) was further examined with dehydrated plastics. These evaluations indicate that dehydrating the plastics reduced, but did not eliminate, high TAN values and that heat alone caused the lost physicals. Alternative HFC refrigerants had little impact on plastics; some polyolester lubricants caused identifiable changes.

Cavestri, R.C.

1993-12-01

230

A recirculation apparatus for vapor–liquid equilibrium measurements of refrigerants. Binary mixtures of R600a, R134a and R236fa  

Microsoft Academic Search

An apparatus for the measurement of vapor–liquid equilibria (P–T–x–y) data of refrigerant systems was designed, built and tested. The recirculation method was used and the vapor phase was forced through the liquid phase by a magnetic pump. The thermodynamic equilibrium was reached in a visual cell with an internal volume of 50 cm3. The compositions of the phases were analyzed

Sergio Bobbo; Roman Stryjek; Nicola Elvassore; Alberto Bertucco

1998-01-01

231

Alternatives to CFC-114 in high-temperature heat pumps: Compressor performance with HFC-236ea and HFC-236fa  

SciTech Connect

The paper gives results of comprehensive calorimeter tests on a semihermetic compressor with chlorofluorocarbon (CFC)-114, hydrofluorocarbon (HFC)-236ea, and HFC-236fa over a wide range of temperature test conditions: evaporating temperatures from 0 to 35 C and condensing temperatures from 40 to 110 C. Parameters assessed as criteria for performance evaluation and for reliable performance include: cooling capacity; electric power input, current, and voltage; coefficients of performance; compressor volumetric and isentropic efficiencies; and discharge and oil temperatures. Polyolester oil was used as lubricant in the compressor.

Kazachki, G.S.; Gage, C.L.; Hendriks, R.V.

1996-12-31

232

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

233

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

234

Optical refrigeration  

NASA Astrophysics Data System (ADS)

The idea of cooling a solid-state optical material by simply shining a laser beam onto it may seem counterintuitive, but this is rapidly becoming a promising technology for future cryocoolers. Here, we chart the evolution of the science of optical refrigeration in rare-earth-doped solids and semiconductors from its origins through to the present day.

Sheik-Bahae, Mansoor; Epstein, Richard I.

2007-12-01

235

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…

Hamilton, Donald L.; And Others

236

Optical refrigeration  

Microsoft Academic Search

The idea of cooling a solid-state optical material by simply shining a laser beam onto it may seem counterintuitive, but this is rapidly becoming a promising technology for future cryocoolers. Here, we chart the evolution of the science of optical refrigeration in rare-earth-doped solids and semiconductors from its origins through to the present day.

Mansoor Sheik-Bahae; Richard I. Epstein

2007-01-01

237

Soundvelocity measurements for HFC134a and HFC152a with a spherical resonator  

Microsoft Academic Search

A spherical acoustic resonator was developed for measuring sound velocities in the gaseous phase and ideal-gas specific heats for new refrigerants. The radius of the spherical resonator, being about 5 cm, was determined by measuring sound velocities in gaseous argon at temperatures from 273 to 348 K and pressures up to 240 kPa. The measurements of 23 sound velocities in

T. Hozumi; T. Koga; H. Sato; K. Watanabe

1993-01-01

238

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

239

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

Microsoft Academic Search

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

S. G Kim; M. S Kim

2002-01-01

240

Performance evaluation of a variable-speed, mixed-refrigerant heat pump  

Microsoft Academic Search

The performance of an innovative heat pump, equipped with a distillation column to shift the composition of a zeotropic refrigerant mixture, was evaluated. The results of the DoE rating tests and seasonal energy calculations are reported with the main cycle refrigerant compositions. No composition shifting of the circulating refrigerant mixture was observed. To demonstrate the potential value of composition shifting,

P. I. Rothfleisch; D. A. Didion

1991-01-01

241

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

SciTech Connect

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

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

2011-02-15

242

Synthesis of HFC134a by isomerization and hydrogenation  

Microsoft Academic Search

For the preparation of HFC-134a, the isomerization of CFC-114 and the hydrogenation of CFC-114a were investigated. Both reactions\\u000a were catalyzed by AlC3 and supported Pd catalysts, respectively. For the comparison purpose, the isomerization of CFC-113 was carried out also.\\u000a With virgin AICI3 catalyst, both isomerization reactions proceeded after a certain induction period probably because the catalyst needed the\\u000a activation by

Dong Jin Suh; Tae-Jin Park; Byung-Gwon Lee; Kun-You Park

1996-01-01

243

Halocarbon Refrigerant Detection Methods.  

National Technical Information Service (NTIS)

The Montreal Protocol and the U.S. Clean Air Act limit the production of ozone-depleting substances, including many refrigerants. Three options for cost-effectively phasing out these refrigerants from Army installations are: (1) refrigerant containment, (...

R. E. Tapscott C. W. Sohn

1996-01-01

244

Recovery efficiency of the hydrofluorocarbon (HFC?134a) by activated carbons of different physicochemical properties  

Microsoft Academic Search

The adsorption characteristics of 1,1,1,2?tetrafluoroethane (HFC?134a) on activated carbon were investigated to evaluate the recovery efficiency of HFC?134a by six activated carbons (two granular activated carbons (GAC1 and GAC2), one high?surface area activated carbon (HAC), and three activated carbon fibers (ACF10, ACF15, and ACF20)). HFC?134a adsorption on the activated carbons increased with increase in the specific surface area and pore

Naohito Kawasaki; Seiki Tanada; Takeo Nakamura; Takashi Ohue; Ikuo Abe

1999-01-01

245

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

246

Research on HFC network broadband access using WLAN technology  

NASA Astrophysics Data System (ADS)

Current broadband access system such as ADSL can not satisfy the network applications as the development of network services. In this paper, we proposed to use WLAN technology on the HFC network as a terminal broadband access plan. First of all, theoretical analysis is given to support the feasibility of using WLAN technology on the HFC network. Then, transmission experiments and results of the proposed plan are described in this paper. The key point of the plan is to use a WLAN access point device as a modem to modulate the baseband Ethernet signal into 2.4GHz WLAN signal which then be transmitted via coaxial cable(COAX). The experimental results show that the average traffic throughput of the system could reach to approximate 20Mbps which is the theoretical throughput of 802.11g WLAN transmission. And the transmission throughput has no remarkable change no matter there is CATV signal in the system or not. Finally, conclusions are drawn out: The proposed system can work properly. WLAN signal is quite suitable to be transmitted in the coaxial cable. CATV signal and WLAN signal are not interfering with each other in the system. Using WLAN on the existing coaxial cable which has already accessed to thousands of people's home could be a cost-effective plan for broadband access on the HFC network.

Chang, Yuguang; Liu, Deming; Zhang, Shu; Wu, Guangsheng

2007-12-01

247

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

248

Thermal conductivity of gaseous HFC-134a, HFC-143a, HCFC-141b, and HCFC-142b  

NASA Astrophysics Data System (ADS)

The thermal conductivity of new environmentally acceptable fluorocarbons HFC-134a (CH2FCF3), HFC-143a (CH3CF3), HCFC-141b (CH3CCl2F), and HCFC-142b (CH3CCl2F) in the gaseous phase has been measured in the temperature range 293 353 K at pressures up to 4 MPa. The thermal conductivity has been measured with a coaxial-cylinder cell on a relative basis. The apparatus was calibrated with He, Ne, Ar, Kr, N2, CH4, and SF6 as reference fluids. The uncertainty of the experimental data obtained is estimated to be within 2% except for the uncertainty associated with the reference thermal-conductivity values. The excess thermal conductivity has been correlated satisfactorily as a function of density.

Tanaka, Y.; Nakata, M.; Makita, T.

1991-11-01

249

Refrigerator Module, System and Process.  

National Technical Information Service (NTIS)

A hermetically sealed, valve-free assembly containing helium 3 or other refrigerant is used in a refrigerator module including a refrigerant evaporator, a refrigerant condenser, and a refrigerant adsorption pump serially connected but thermally isolated, ...

W. F. Brooks P. Kittel

1981-01-01

250

Helmholtz-Type Equations of State for Hydrocarbon Refrigerant Mixtures of Propane\\/ n Butane, Propane\\/Isobutane, n Butane\\/Isobutane, and Propane\\/ n Butane\\/Isobutane  

Microsoft Academic Search

Highly accurate thermodynamic property models for binary and ternary hydrocarbon mixtures containing propane, n-butane, and isobutane have been developed. In the present model, reliable equations of state explicit in Helmholtz free energy for these three hydrocarbons that have already been developed by the present authors have been adapted. The excess term used to represent the contribution of mixing was optimized

H. Miyamoto; K. Watanabe

2003-01-01

251

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

252

Thermodynamic and transport properties of some alternative ozone-safe refrigerants for industrial refrigeration equipment: Study in Belarus and Ukraine  

Microsoft Academic Search

The study of several hydrofluorocarbons (HFC) and fluorocarbons (FC) and their binary mixtures that have no ozone-depleting ability is being carried Out in the framework of Belarus National Program. The fluids include HFCs R134a. R152a, R135, and R32, and FC R218. The following properties are being investigated: ( I ) phase equilibrium parameters including the boiling and condensing curve and

A. J. Grebenkov; V. P. Zhelezny; P. M. Klepatsky; O. V. Beljajeva; Yu. A. Chernjak; Yu. G. Kotelevsky; B. D. Timofejev

1996-01-01

253

Refrigerant reclaim apparatus  

SciTech Connect

This patent describes an apparatus for reclaiming refrigerant. It comprises: cleaning means for removing gaseous or liquid refrigerant from a container, vaporizing all of the liquid refrigerant and separating oil from the gaseous refrigerant, a compressor for receiving and compressing the gaseous refrigerant from the containers, a condenser for receiving and condensing the gaseous refrigerant from the compressor, storing means for receiving and storing the liquid refrigerant from the condenser, removal means for removing condensed refrigerant out from the storing means, and evacuations beans for evacuating high pressure gaseous refrigerant from the entire apparatus after all of the condenser refrigerant has been removed the storing means; the evacuation means comprised of the three-way solenoid valve and an operator activated switch functionally associated with the solenoid valve wherein the activation of the switch caused the evacuation of high pressure gaseous refrigerant; and the evacuation means located adjacent to and in fluid communication with the exit of the compressor.

Van Steenburgh, L.R.

1992-02-11

254

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

255

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

Microsoft Academic Search

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

S. L Bapat

2000-01-01

256

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

EPA Science Inventory

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

257

Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels--One-Year 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 the first year of a multi-year study for the full-thickness panels and for about 1-1/2 years of aging for the core-foam specimens.

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

1999-09-27

258

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

259

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

260

The performance of a triple pressure level absorption cycle (TPLAC) with working fluids based on the absorbent DMEU and the refrigerants R22, R32, R124, R125, R134a and R152a  

Microsoft Academic Search

This paper compares the performance of a single-stage triple pressure level (TPL) absorption cycle with different refrigerant–absorbent pairs. Four HFC refrigerants namely: R32, R125, R134a and R152a which are alternative to HCFC, such as R22 and R124, in combination with the absorbent dimethylethylenurea (DMEU) were considered. The highest coefficient of performance (COP) and the lowest circulation ratio (f), were found

M. Jelinek; A. Levy; I. Borde

2008-01-01

261

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 ...

262

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...

263

Atmospheric Degradation Mechanisms of Hydrogen Containing Chlorofluorocarbons (HCFC) and Fluorocarbons (HFC).  

National Technical Information Service (NTIS)

The current knowledge of atmospheric degradation of hydrogen containing chlorofluorocarbons (HCFC 22 (CHClF2), HCFC 123 (CHCl2CF3), HCFC 124 (CHClFCF3), HCFC 141b (CFCl2CH3), HCFC 142b (CF2ClCH3)) and fluorocarbons (HFC 125 (CHF2CF3), HFC 134a (CH2FCF3), ...

R. Zellner

1990-01-01

264

Adsorption of hydrofluorocarbons HFC-134 and HFC-134A on X and Y zeolites: Effect of ion-exchange on selectivity and heat of adsorption  

SciTech Connect

Adsorption isotherms and heats of adsorption were measured for HFC-134 (1,1,2,2-tetrafluoroethane) and HFC-134a (1,1,1,2-tetrafluoroethane) on a series of ion-exchanged (H, Li, Na, Rb, Cs) faujasites using volumetric and calorimetric techniques. The species and number of ions present in the zeolite strongly influence the heats of adsorption and the preferential adsorption of HFC-134 compared to HFC-134a. The selectivity is considerably higher in X than in Y zeolites because of the larger number of nonframework ions in X zeolites. The saturation capacity is six molecules per supercavity for both HFCs. The differences in observed heats of adsorption (except for RbX) can be explained by reasonable and consistent values of dispersion and ion-dipole electrostatic energies. The high selectivities for NaX and RbX indicate that either zeolite would be highly effective for gas separation.

Savitz, S.; Siperstein, F.R.; Huber, R.; Tieri, S.M.; Gorte, R.J.; Myers, A.L.; Grey, C.P.; Corbin, D.R.

1999-09-30

265

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

266

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

1999-01-01

267

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

268

Atmospheric lifetimes of HFC143a and HFC245fa: Flash photolysis resonance fluorescence measurements of the OH reaction rate constants  

Microsoft Academic Search

Rate constants for the reactions of hydroxyl radicals with CHâCFâ (HFC-143a) and CHFâCHâCFâ (HFC-245fa) have been measured using the flash photolysis resonance fluorescence technique over the temperature range 273-370 K. A data analysis procedure is presented which should minimize rate constant errors introduced by the possible effects of radical diffusion. Arrhenius expressions have been derived for the reactions of OH

Vladimir L. Orkin; Robert E. Huie; Michael J. Kurylo

1996-01-01

269

Refrigerant recovery system  

SciTech Connect

This patent describes improvement in a refrigerant recovery apparatus of the type having inlet means for connecting to a refrigerant air system to withdraw refrigerant from the system, expansion means for converting refrigerant received from the system in liquid phase to a gaseous refrigerant, a compressor having a suction chamber with a suction inlet for receiving and pressurizing the gaseous refrigerant, the compressor having a housing containing oil for lubricating the compressor, a condenser for receiving the pressurized gaseous refrigerant and condensing it to liquid refrigerant, and a storage chamber for storing the liquid refrigerant. The improvement comprises in combination: oil separator means mounted exterior of the housing to one end of an inlet line, which has another end connected to the suction inlet of the compressor for receiving the flow of refrigerant from the refrigerated air system for separating out oil mixed with the refrigerant being received from the refrigerated air system prior to the refrigerant entering the suction inlet of the compressor; and the oil separator means being mounted at a lower elevation than the suction inlet of the compressor, the inlet line being unrestricted for allowing refrigerant flow to the compressor and oil from the compressor for draining oil in the housing of the compressor above the suction inlet back through the inlet line into the oil separator means when the compressor is not operating.

Abraham, A.W.

1991-08-20

270

Energy saving refrigeration system  

SciTech Connect

A refrigeration system having an increasing efficiency of operation and reduction in power consumption. Low head pressure and subcooling the liquid refrigerant emitted from the remote condenser, the efficiency of operation of the compressor of the refrigeration system can be substantially increased. The particular type of refrigeration system of concern generally includes a compressor for compressing a gaseous refrigerant, a condenser for condensing the gaseous refrigerant and subcooling the liquid refrigerant, a receiver for receiving the liquid and a plurality of display cases having evaporators for evaporating the liquid refrigerant. The gaseous refrigerant passing through the condenser is first condensed into a liquid at a condensing temperature of approximately 10/sup 0/ to 25/sup 0/ F above a preselected cooling temperature. The condensed liquid is then subcooled to the preselected cooling temperature which should be preferably either approximately 50/sup 0/ F or the temperature of the ambient atmosphere surrounding the condenser, whichever is higher.

Bowman, E.; Ibrahim, F.

1983-02-15

271

Energy saving refrigeration system  

SciTech Connect

A refrigeration system having an increased efficiency of operation and reduction in power consumption. Low head pressure and subcooling the liquid refrigerant emitted from the remote condenser, the efficiency of operation of the compressor of the refrigeration system can be substantially increased. The particular type of refrigeration system of concern generally includes a compressor for compressing a gaseous refrigerant, a condenser for condensing the gaseous refrigerant and subcooling the liquid refrigerant, a receiver for receiving the liquid and a plurality of display cases having evaporators for evaporating the liquid refrigerant. The gaseous refrigerant passing through the condenser is first condensed into a liquid at a condensing temperature of approximately 10 to 25/sup 0/ F Above a preselected cooling temperature. The condensed liquid is then subcooled to the preselected cooling temperature which should be preferably either approximately 50/sup 0/ F or the temperature of the ambient atmosphere surrounding the condenser, whichever is higher.

Abraham, F.; Bowman, E.

1982-12-28

272

Energy saving refrigeration system  

SciTech Connect

A refrigeration system is claimed which has an increased efficiency of operation and reduction in power consumption. By maintaining a low head pressure and subcooling the liquid refrigerant emitted from the remote condenser, the efficiency of operation of the compressor of the refrigeration system can be substantially increased. The particular type of refrigeration system of concern generally includes a compressor for compressing a gaseous refrigerant, a condenser for condensing the gaseous refrigerant and subcooling the liquid refrigerant, a receiver for receiving the liquid and a plurality of display cases having evaporators for evaporating the liquid refrigerant. The gaseous refrigerant passing through the condenser is first condensed into a liquid at a condensing temperature of approximately 10 to 25/sup 0/ F above a preselected cooling temperature. The condensed liquid is then subcooled to the preselected cooling temperature which should be preferably either approximately 50/sup 0/ F or the temperature of the ambient atmosphere surrounding the condenser, whichever is higher.

Abraham, F.; Bowman, E.

1981-09-01

273

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

274

FURTHER DEVELOPMENT OF A MIXED GAS JOULE THOMSON REFRIGERATOR  

Microsoft Academic Search

A mixed gas Joule Thomson refrigerator has distinct advantages over other cryocooler for certain applications. The system is compact, has good thermodynamic efficiency and low levels of vibration and noise. Further development of this refrigeration machine is possible by optimization of the gas mixture composition. A method was developed which permits a reduction by a large factor in the number

A. Alexeev; Ch. Haberstroh; H. Quack

275

An investigation of the performance of a scroll compressor under liquid refrigerant injection  

Microsoft Academic Search

In this study, fundamental and practical influence of liquid refrigerant injection on the performance of a refrigerant scroll compressor has been investigated experimentally and theoretically. In the theoretical analysis, a compression model of vapor\\/liquid mixture is developed by taking account of heat transfer from the cylinder wall to suction, compression and injection refrigerant. An experiment has been done under the

Asit K. Dutta; Tadashi Yanagisawa; Mitsuhiro Fukuta

2001-01-01

276

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

NASA Astrophysics Data System (ADS)

The cyclic analysis of Stirling cycle working with a single gaseous fluid is modified to suit two-component two-phase mixtures. When the results were examined carefully, these showed that a substantial increase in cooling effect is obtained. In order to understand how the two-component two-phase working fluid functions in the Stirling cooler, some other processes, generally not coming into picture with a single gaseous fluid, are also considered to get good idea about the working of the cooler and then the estimates about the performance of the cooler are obtained. The processes include, simultaneous compression of gases with different ratios of Cp and Cv, the drop-wise condensation, isentropic expansion of liquid in presence of other gas, the entrainment process as observed in heat pipes, and saturation process as observed in air humidification process. The change in regenerator effectiveness due to condensation in the regenerator also has to be considered. How the above mentioned processes are affecting the system performance is discussed in detail. The analysis shows that the Stirling cycle and vapour compression cycle with isentropic expansion operate simultaneously. The criterion for selection of the gaseous carrier fluid and the condensable fluid, which undergoes phase change is established. For selection of carrier gas, helium and hydrogen are considered and for the condensable fluid, nitrogen, carbon mono-oxide, nitrogen-tri-fluoride and neon are compared. Using the above mentioned criterion, helium and nitrogen combination has been chosen for cold tip temperatures in liquid nitrogen temperature range. The paper discusses the analytical approach and the results indicate that the presence of vapour compression cycle with isentropic expansion, operating under a small difference between the condensation and evaporation temperatures, leads to high values of cooling effect and coefficient of performance (COP). It also shows that beyond a certain concentration, the cooling effect starts dropping and becomes zero at certain higher concentration. It can be mentioned that no changes in the hardware are necessary as the cooler can operate at pressures lower than normal working pressure and still provide large capacity with marginally higher power input.

Bapat, S. L.

2000-01-01

277

Benchtop, Refrigerator Centrifuges  

Cancer.gov

CHECKLIST FOR BENCHTOP, REFRIGERATED CENTRIFUGES CG 15 Any program area utilizing the SAIC-Frederick procurement system for benchtop, refrigerated centrifuges must adhere to this process Instructions: 1) Check off model from list below and attach a list

278

Evolution of Refrigerant Application.  

National Technical Information Service (NTIS)

The paper reviews the development of chlorofluorocarbon refrigerants, the implemented replacements of ozone depleting fluids, other considered alternatives, and the prospect for next-generation refrigerants in response to climate change concerns. Convinci...

P. A. Domanski

1999-01-01

279

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

280

Refrigeration for Cryogenic Sensors.  

National Technical Information Service (NTIS)

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 ...

M. G. Gasser

1983-01-01

281

Refrigeration for Cryogenic Sensors  

SciTech Connect

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.

1983-12-01

282

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.

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

1994-05-27

283

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

284

Human Inhalation of Halon 1301, HFC-134a and HFC-227ea for Collection of Pharmacokinetic Data.  

National Technical Information Service (NTIS)

International agreement and regulatory decisions have driven activities to replace ozone depleting chemicals (ODCs) in fire suppression and refrigeration applications. In order to validate a human physiologically based pharmacokinetic model designed for u...

A. Vinegar G. W. Jepson R. S. Cook J. D. McCafferty M. C. Caracci

1997-01-01

285

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

286

Electrocaloric refrigeration for superconductors  

Microsoft Academic Search

A solid state type of refrigeration, which utilizes the electrocaloric effect in certain dielectric materials, has been investigated. Such a refrigerator would operate with a load at 4 K and reject heat to a reservoir at 15 K. Heat switches for such a refrigerator were studied. One type was a multiple leaf contract switch. The other type was a magnetothermal

R. Radebaugh; J. D. Siegwarth; W. N. Lawless; A. J. Morrow

1977-01-01

287

Molecular Modeling of Fluoropropene Refrigerants.  

PubMed

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

Raabe, Gabriele

2012-05-01

288

Saturation properties of the refrigerant 143A  

Microsoft Academic Search

1,1,1-Trifluoroethane (CH3?CF3; R143a) is currently under consideration as a potential candidate as a component in refrigerant mixtures. Among other things, the accurate knowledge of saturation properties of the pure fluids is a pre-requisite for evaluation of mixture properties. There is a considerable amount of scatter in the available data for R143a. This article presents a conciliation of saturation property data

K Srinivasan; L. R Oellrich

1997-01-01

289

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,...

290

HFC365mfc: A Versatile Blowing Agent for Rigid Polyurethane Foams  

Microsoft Academic Search

HFC-365mfc and HFC-245fa are now well documented as promising blowing agents, and their production will come on stream in a few years. However, none has the same ideal boiling point as CFC-11 or HCFC-141b. Blends may offer the best compromise to customize the different end-use requirements. Two different directions for further developments have emerged from our work:Two binary, non-azeotropic blends

L. Zipfel; K. Börner; W Krücke; P Barthélemy; P Dournel

1999-01-01

291

Recent increases in global HFC23 emissions and early trends in other HFCs  

Microsoft Academic Search

Hydrofluorocarbons (HFCs) generally have high global warming potentials and are used as substitutes for ozone-depleting gases. Trifluoromethane (HFC-23) is an unintended by-product of chlorodifluoromethane (HCFC-22) production and has the longest lifetime (270 yr) and largest 100-yr global warming potential (14,800) of all the most commonly produced HFCs. Firn-air and ambient air measurements of HFC-23 from three firn sampling excursions to

Steve Montzka; Lambert Kuijpers; Lloyd Miller; Mark Battle; Murat Aydin; Kristal Verhulst; Eric Saltzman; David Fahey; Ben Miller; Bradley Hall

2010-01-01

292

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

293

Alternate refrigerants and lubricants for the microclimate cooling system. Final report, December 1991-March 1992  

SciTech Connect

This research identified, explored, and evaluated the use of alternative refrigerants and lubricants in vapor compression cycle for refrigeration. With impending phaseouts of chlorofluorocarbons (CFC`s), there is an immediate need to find suitable replacements for use existing systems, as well as new systems designed to operate with the new substances. The alternative refrigerants and lubricants have certain problems when used in retrofitted systems. Differences in properties must also be considered when designing a system for use with the alternatives. For Microclimate Cooling Systems, HFC-134a is considered when designing a system for use with the alternatives. For Microclimate Cooling Systems, HFC-134A is considered to be the best candidate. R-134a requires a higher pressure increase to achieve a good refigeration cycle; however, 134a necessities the use of a new lubricant. For 134a, a polyolester lubricant is the best choice. It has desirable properties and a very low ecotoxicity rating. It is also compatible with CFC-12. This allows a system run with an ester based lubricant and R-12 to be easily retrofitted to operate on 134.

Wolfson, M.W.

1992-09-01

294

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

NASA Astrophysics Data System (ADS)

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

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

1993-04-01

295

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

NASA Astrophysics Data System (ADS)

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

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

1994-02-01

296

Characteristics of a Mixed Refrigerant Vapor Compression Cycle  

NASA Astrophysics Data System (ADS)

In comparison with conventional refrigerants, the use of non-azeotropic binary mixtures of refrigerants in vapor compression refrigerating systems can result in extension of the application limits, higher reliability, and savings in power consumption. This paper discusses the high temperature heat pump system performance operating with mixed refrigerants. In order to survey the system performances with various mixtures, six kinds of mixtures are examined : R22-R1l4, R22-R11, R12-R114, R12-R11, R 12-R113, and R22-R12. Thermodynamic properties of the first five mixtures are calculated from the Peng-Robinson equation of state with the mixing rules proposed by Ototake, and R22-R12 mixtures by the BWR type equation of state proposed by Kagawa et al. When counter-flow heat exchangers with large surface areas are used for the evaporator and the condenser, the temperature differences between the refrigerant and the heat sink / source fluids can be reduced, and so the energy waste resulting from irreversible heat trasfer can be reduced. Comparing the mixed refrigerants with the pure ones by fixing the refrigerant temperature at the evaporator inlet and the dewpoint temperature at the condenser, higher coefficients of performance (COP), lower condensing pressures, and lower pressure ratios in the refrigerant compressor can be realized. But the performances of the mixtures with R114 as a less volatile component are not so good. When the heat transfer surface area is not large, the mean temperature difference becomes large. If the dewpoint temperatures at the evaporator and the condenser fixed, the range of composition for the improvement of the COP is restricted.

Hihara, Eiji; Muneta, Yoshihiro; Saito, Takamoto

297

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; Fricke, Brian A [ORNL; Vineyard, Edward Allan [ORNL

2012-01-01

298

Isochoric p–?–T Measurements for Binary Refrigerant Mixtures Containing Difluoromethane (R32), Pentafluoroethane (R125), 1,1,1,2-Tetrafluoroethane (R134a), and 1,1,1-Trifluoroethane (R143a) from 200 to 400 K at Pressures to 35 MPa  

Microsoft Academic Search

The p–?–T relationships were measured for binary refrigerant mixtures by an isochoric method with gravimetric determinations of the amount of substance. Temperatures ranged from 200 to 400 K, while pressures extended up to 35 MPa. Measurements were conducted on compressed gas and liquid samples with the following mole fraction compositions: 0.4997 R32+0.5003 R134a, 0.3288 R32+0.6712 R134a, 0.4996 R32+0.5004 R125, 0.5001

J. W. Magee; W. M. Haynes

2000-01-01

299

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

300

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

301

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

302

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

303

Chemically assisted mechanical refrigeration process  

SciTech Connect

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

304

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

305

Chemically assisted mechanical refrigeration process  

SciTech Connect

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

306

Thermal diffusion factor of Stockmayer mixtures: A non-equilibrium molecular dynamic study  

NASA Astrophysics Data System (ADS)

Thermal diffusion factors (TDFs) in binary Stockmayer model mixtures as well as real mixtures of four refrigerants with N2 and CO have been calculated by NEMD simulations. The results of the model mixtures show that the TDF increases with the two component dipole moment ratio, however it is not a sensitive function of the ratio of the moment of inertia and the intermolecular cutoff distance. The calculated TDFs in N2/CO-refrigerants mixtures were equal for less polar refrigerants, however the TDFs of CO mixtures increase more than that of the N2 mixtures with the dipole strength of the refrigerant.

Yeganegi, Saeid; Kameli, Panah

2013-03-01

307

Miscibility of lubricants with refrigerants, Phase 1  

SciTech Connect

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

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

1992-10-01

308

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.

2013-10-01

309

Electrocaloric Refrigeration for Superconductors.  

National Technical Information Service (NTIS)

A solid state type of refrigeration, which utilizes the electrocaloric effect in certain dielectric materials, has been investigated. Such a refrigerator would operate with a load at 4 K and reject heat to a reservoir at 15 K. Heat switches for such a ref...

A. J. Morrow J. D. Siegwarth R. Radebaugh W. N. Lawless

1977-01-01

310

Electrocaloric Refrigeration for Superconductors.  

National Technical Information Service (NTIS)

The goal of the program is to demonstrate the feasibility of a refrigerator based on the electrocaloric effect. It is planned to develop a prototype refrigerator which will absorb on the order of 1 watt at 4 K and have an upper reservoir temperature of 15...

1974-01-01

311

Thermoacoustic engines and refrigerators  

NASA Astrophysics Data System (ADS)

Thermoacoustic engines and refrigerators use gas inertia and compressibility to eliminate many of the mechanical contrivances required by traditional engines and refrigerators while providing potentially attractive options that might reduce environmental impacts. The operation of both standing-wave and traveling-wave devices will be described and illustrated with thermoacoustic devices that have been used outside the laboratory.

Garrett, Steven L.

2012-06-01

312

Refrigerant recovery device  

Microsoft Academic Search

This patent describes a lightweight, portable unmotorized apparatus for removing a condensable gas from a vessel comprised of the gas. It comprises a first container adapted to contain a refrigerant, conduit means partially disposed within the container for allowing at least a portion of the refrigerant to flow from the first container and to vent to an area of lower

Daily

1992-01-01

313

Adsorption Refrigeration System  

Microsoft Academic Search

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

Kai Wang; Edward Allan Vineyard

2011-01-01

314

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

Code of Federal Regulations, 2010 CFR

... false Definitions concerning commercial refrigerators, freezers and refrigerator-freezers. 431.62 Section 431.62...COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and Refrigerator-Freezers...

2009-01-01

315

Ranking of refrigerants.  

PubMed

Environmental ranking of refrigerants is of need in many instances. The aim is to assess the relative environmental hazard posed by 40 refrigerants, including those used in the past, those presently used, and some proposed substitutes. Ranking is based upon ozone depletion potential, global warming potential, and atmospheric lifetime and is achieved by applying the Hasse diagram technique, a mathematical method that allows us to assess order relationships of chemicals. The refrigerants are divided into 13 classes, of which the chlorofluorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, hydrofluoroethers, and hydrocarbons contain the largest number of single substances. The dominance degree, a method for measuring order relationships among classes, is discussed and applied to the 13 refrigerant classes. The results show that some hydrofluoroethers are as problematic as the hydrofluorocarbons. Hydrocarbons and ammonia are the least problematic refrigerants with respect to the three environmental properties. PMID:18497145

Restrepo, Guillermo; Weckert, Monika; Brüggemann, Rainer; Gerstmann, Silke; Frank, Hartmut

2008-04-15

316

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

317

Toxicological evaluation of 1,1,1,2,2-pentafluoroethane (HFC-125).  

PubMed

Acute, subacute, and subchronic inhalation toxicity studies, developmental toxicity studies, a cardiac sensitization evaluation, and mutagenicity assays were conducted with pentafluoroethane (HFC-125). In the acute study, rats were exposed to a single concentration of 800,000 ppm for 4 hr. Ataxic gait and abnormal respiration were observed during exposure but not after exposure. There was no mortality or other signs of toxicity. Repeated exposures of rats to 50,000 ppm, 6 hr/day, 5 days/week for either 4 or 13 weeks elicited no effects on body weight, food consumption, clinical signs, hematology, biochemistry, urinalysis, organ weight, or tissue morphology. Positive evidence of cardiac sensitization in response to an intravenous epinephrine challenge in dogs was seen at 100,000 ppm and above, but not at 75,000 ppm. HFC-125 was not mutagenic in Salmonella typhimurium and Escherichia coli strains at concentrations of 20 to 100% (v/v) with and without activation. No evidence of clastogenic activity was observed in cultured Chinese hamster ovary (CHO) cells or human lymphocytes at < or = 70% HFC-125 when treatments were conducted for 3-4 hr with activation or for 24 and 48 hr (human lymphocytes only) without activation. However, a statistically significant increase in chromosomally aberrant cells was observed in CHO cells at 60% HFC-125 when treatment without activation was extended to 48 hr. The biological significance of this effect is questionable since signs of severe toxicity were also present. In vivo, no micronuclei were induced in mouse bone marrow at concentrations as high as 600,000 ppm HFC-125 for a 6-hr exposure. In addition, HFC-125 did not induce embryotoxic or teratogenic effects in either the rat or the rabbit at exposure concentrations as high as 50,000 ppm. PMID:8835232

Kawano, T; Trochimowicz, H J; Malinverno, G; Rusch, G M

1995-12-01

318

Pulse Tube Refrigerator  

NASA Astrophysics Data System (ADS)

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

Matsubara, Yoichi

319

Ejectors: applications in refrigeration technology  

Microsoft Academic Search

This paper provides a literature review on ejectors and their applications in refrigeration. A number of studies are grouped and discussed in several topics, i.e. background and theory of ejector and jet refrigeration cycle, performance characteristics, working fluid and improvement of jet refrigerator. Moreover, other applications of an ejector in other types of refrigeration system are also described.

Kanjanapon Chunnanond; Satha Aphornratana

2004-01-01

320

Rotary two-phase refrigeration apparatus and method  

SciTech Connect

Rotary vacuum evaporation of a primary refrigerant cools a secondary refrigerant mixed with it. The secondary refrigerant does not change state and meanders through a low pressure cooling circuit for refrigeration applications. The primary refrigerant changes state and remains in a short and secure circuit. Evaporation is produced at a surface around the axis of rotation and within the mixture by opposed centrifugal and centripetal forces acting through a narrow afferent mesial passage between rotating disks mounted on a hollow shaft. Vapor is stripped from the surface, scrubbed by cyclonic flow through the afferent mesial passage, and condensed by a centrifugal compressor, which is a centrifugal pump having its inlet communicating with the bore of the hollow shaft and the afferent mesial passage. Latent heat is drawn off by water, making this a water heater, and the water is produced by de-humidification. The primary refrigerant and the secondary refrigerant are cheap and environmentally harmless, e.g. propylene glycol and acetone. A method and apparatus for refrigeration using only water is disclosed. Energy efficiency is maximized by avoidance of positive displacement pumps and narrow conduits, and by operation during times when excess power is in the grid. 7 figs.

McCutchen, W.H.

1994-01-04

321

Actinide extraction from simulated and irradiated spent nuclear fuel using TBP solutions in HFC-134a  

SciTech Connect

It was demonstrated that solutions of TBP-nitric acid adduct in liquid Freon HFC-134a (1.2 MPa, 25 deg. C) allowed for recovery of uranium with nearly the same effectiveness as supercritical CO{sub 2} at 30 MPa. At nearly quantitative recovery of U and Pu, a DF of ca. 10 can be attained on dissolution and extraction of simulated SNF samples. The possibility of recovery of actinides contained in cakes produced by oxide conversion of simulated and irradiated SNF with solutions of TBP and DBE in Freon HFC-134a was shown. (authors)

Shadrin, A.; Babain, V.; Kamachev, V.; Murzin, A.; Shafikov, D.; Dormidonova, A. [Khlopin Radium Institute, RPA, 28, 2-nd Murinskii ay., St-Petersburg (Russian Federation)

2008-07-01

322

Inhalation uptake and metabolism of Halon 1301 replacement candidates, HFC-227ea, HFC-125, and FC-218. Interim report, March-December 1994  

SciTech Connect

The purpose of this study was to measure the tissue to air partition coefficients and to describe the uptake and distribution kinetics of bromotrifluoromethane`s (Halon 1301) proposed replacement chemicals HFC-227ea, HFC-125, and FC-218. Parallel information pertaining to Halon 1301 and CF(3)I can be found in AL/OE-TR-1994-0068. Tissue to air partition coefficients were determined using the vial equilibration method. Inhalation pharmacokinetics for all Halon 1301 replacements were determined experimentally in Fischer 344 (F-344) male rats via a closed chamber recirculating gas uptake methods. A physiologically-based pharmacokinetic (PBPK) model was used to describe mathematically the disposition and metabolism of the chemicals employing chemical-specific parameters and apparent whole-body metabolic constants calculated from these experiments.

Creech, J.R.; Black, R.K.; Neurath, S.K.; Williams, R.J.; Jepson, G.W.

1995-02-01

323

Evaluation of the use of multicomponent refrigerants in gas-fired heat pumps. Final report Jan 82Feb 83  

Microsoft Academic Search

The use of multicomponent refrigerants in heat pump cycles was evaluated theoretically and experimentally; in the theoretical evaluation, a vapor compression cycle using refrigerant mixtures was formulated and analyzed. The results of this analysis show that the achievable improvement in efficiency using optimum mixtures would be on the order of 20 to 25%. A laboratory test stand was also built

Mathiprakasam

1983-01-01

324

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 (e.g., enhancements of 13 pptv and 11 pptv for CFC-11 and CFC-12, respectively). Emissions estimates of HFC-152a (0.98±0.05 Gg) and HFC-134a (1.40±0.11 Gg) in LA County for 2008 were obtained using the observed HFC:CO enhancement ratio. The emission rates were extrapolated to the SoCAB (1.48±0.07 Gg for HFC-152a and 2.12±0.17 Gg for HFC-134a) and US (30.1±1.5 Gg for HFC-152a and 43.0±3.4 Gg for HFC-134a) using population data. In addition, emission rates of the two HFCs in LA County and SoCAB also were calculated by a second method that utilizes air quality modeling. Estimates obtained using both methods agree well.

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

2010-11-01

325

Refrigeration systems program summary.  

National Technical Information Service (NTIS)

In addition to saving energy, deploying advanced refrigeration technologies can substantially benefit the environment. Chlorofluorocarbons (CFCs) have been identified as a major cause of potential global climate change and about 20% of the CFCs consumed b...

1991-01-01

326

Electroluminescence refrigeration in semiconductors  

Microsoft Academic Search

An InGaAs light emitting diode monolithically integrated with a suspended lens is proposed as a prototype semiconductor electroluminescence refrigeration device. Simulations predict that a temperature drop up to 6degC is achievable in this device.

S.-Q. Yu; D. Ding; J.-B. Wang; S. R. Johnson; Y.-H. Zhang

2006-01-01

327

Improved Icy Ball Refrigerator.  

National Technical Information Service (NTIS)

Two Icy Ball Refrigerator Units of improved designed compared with earlier units fabricated under this program were tested in the laboratory and in the field. Under both laboratory and hot-wet field conditions the units performed reliably. Adequate inside...

N. Montanarelli

1974-01-01

328

An Improved Helium Refrigerator.  

National Technical Information Service (NTIS)

An improved helium refrigerator is described with a plurality of counter-flow heat exchangers and a maximum reserve cooling capacity. The final or low temperature heat exchanger is substantially filled with liquid helium. An electrical bridge circuit incl...

E. R. Wiebe

1974-01-01

329

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

330

Prediction of pressure drop in refrigerant–lubricant oil flows with high contents of oil and refrigerant outgassing in small diameter tubes  

Microsoft Academic Search

This paper presents an analysis of the available prediction methodologies for frictional pressure drop in two-phase gas–liquid flows of oil-rich refrigerant–lubricant oil mixtures in a small diameter tube. In this particular application, the liquid–vapour phase change (flashing) is caused by a reduction of the solubility of the refrigerant in the mixture. The very low vapour pressure of the oil causes

J. R. Barbosa; V. T. Lacerda; A. T. Prata

2004-01-01

331

Two-way Broadband CATV-HFC Networks: State-of-the-Art and Future Trends  

Microsoft Academic Search

Cable modems allow two way digital data transmission between households and a central neighborhood server. In this overview we briefly describe some of the common characteristics of the Hybrid Fiber Coax (HFC) operation as presented by several standards bodies (both completed standards and works in progress). This includes a description and comparison of the media access control and physical layer

Stephen Perkins; Alan Gatherer

1999-01-01

332

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

EPA Science Inventory

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

333

HEAT TRANSFER EVALUATION OF HFC-236EA WITH HIGH PERFORMANCE ENHANCED TUBES IN CONDENSATION AND EVAPORATION  

EPA Science Inventory

The report gives results of an evaluation of the heat transfer performance of pure hydrofluorocarbon (HFC)-236ea for high performance enhanced tubes which had not been previously used in Navy shipboard chillers. Shell-side heat transfer coefficient data are presented for condensa...

334

PhD-title: Regions' role in the formative phase of an HFC innovation system  

Microsoft Academic Search

The concept of a hydrogen economy captures the high expectations that hydrogen and fuel cell (HFC) technology may bring for the future. According to hydrogen economy supporters, this emerging technology will be able to bring radical changes to all parts of the energy sector through its many application types within transport, stationary and portable devices. If the hydrogen is produced

Anne Nygaard Madsen

335

Evaluated Rate Constants for Selected HCFC's and HFC's with OH and O((sup)1D).  

National Technical Information Service (NTIS)

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 ...

R. F. Hampson M. J. Kurylo S. P. Sander

1990-01-01

336

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

337

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

2012-01-24

338

THERMODYNAMIC PERFORMANCE LIMIT AND EVAPORATOR DESIGN CONSIDERATIONS FOR NARM-BASED DOMESTIC REFRIGERATOR-FREEZER SYSTEMS  

EPA Science Inventory

The paper gives results of an investigation of non-azeotrophic refrigerant mixtures (NARMs) for a two-temperature-level heat exchange process found in a domestic refrigerator-freezer. deal (constant air temperature) heat exhcange processes are assumed. he results allow the effect...

339

21 CFR 1250.34 - Refrigeration equipment.  

Code of Federal Regulations, 2013 CFR

...Land and Air Conveyances, and Vessels § 1250.34 Refrigeration equipment. Each refrigerator shall be equipped with a thermometer located in the warmest portion thereof. Waste water drains from ice boxes, refrigerating equipment, and refrigerated...

2013-04-01

340

Viscosity correlations of normal gases at normal pressures and several HFC refrigerants using the corresponding states theory  

Microsoft Academic Search

Coupling the corresponding states theory with the dimensional analysis method, the viscosity correlations for calculating gas-phase viscosity at normal pressures were proposed by correlating the non-dimensional viscosity ?* with the reduced temperature Tr and the critical compressibility factor ZC. The correlations would apply to monatomic gases, diatomic gases, hydrocarbons and halogenated hydrocarbons. Compared the calculated results with literature data, the

Ying Zhang; Maogang He; Yang Liu; Libin Chen

2011-01-01

341

Experimental investigation of a process cooling system retrofitted with HFC404A refrigerant for precise manufacturing application  

Microsoft Academic Search

Precise-manufacturing facilities, which emphasize accurate and stable machining of the working components to be used in semiconductor\\u000a industry, cannot function properly without appropriate and precise cooling. HCFC (hydro-chloro-floro-carbon) has been commonly\\u000a used as the coolant for precise manufacturing facilities; but it is facing the pressing schedule to be phased out. Additionally,\\u000a the dramatic variation of heat load during high-accuracy and

Fu-Jen Wang; Kuei-I Tsai; Yao-Jun Wang; Hao-Chuan Lee

2011-01-01

342

Cryogenic forced convection refrigerating system  

SciTech Connect

This patent describes the method of refrigerating products by contact with a refrigerating gas which comprises introducing product into a refrigeration zone, contacting the product with the refrigerating gas for a sufficient time to refrigerate it to the appropriate extent and removing the refrigerated product. The improvement for producing the refrigeration gas from a liquid cryogen such that essentially all of the liquid cryogen is fully vaporized before contacting the product comprises: (a) introducing the liquid cryogen, selected from the group consisting of liquid air and liquid nitrogen, at elevated pressure into an ejector as the motive fluid to accelerate a portion of a warm refrigerating gas through the ejector while mixing the cryogen and gas to effect complete vaporization of the liquid cryogen and substantial cooling of the portion of the refrigerating gas resulting in a cold discharge gas which is above the liquefaction temperature of the cryogen; (b) introducing the cold discharge gas into a forced circulation pathway of refrigerating gas and producing a cold refrigerating gas which contacts and refrigerates product and is then at least partially recirculated; (c) sensing the temperature of the refrigerating gas in the forced circulation pathway and controlling the introduction of liquid cryogen with regard to the sensed temperature to maintain the temperature of the discharge gas above the liquefacton temperature of the cryogen utilized.

Klee, D.J.

1988-02-23

343

Downhole pulse tube refrigerators  

SciTech Connect

This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

1997-12-01

344

Development of a Low Noise 10 K J-T (Joule-Thomson) Refrigeration System.  

National Technical Information Service (NTIS)

This report summarizes work done on the development of a low noise Joule-Thomson, microminiature refrigeration system designed for 10 K operation. Topics discussed include: calculation of phase diagram of mixtures of certain hydrocarbon gases with nitroge...

W. A. Little

1987-01-01

345

Gas absorber and refrigeration system using same  

Microsoft Academic Search

A refrigeration system is described comprising: (a) a separator for separating a refrigerant gas from a refrigerant-rich solution to produce a refrigerant-lean solution; (b) a condenser for emitting heat to thereby condense the refrigerant gas received from the separator and an evaporator for absorbing heat to thereby evaporate the condensed refrigerant gas; (c) an absorber assembly including: a precooler for

Dehne

1993-01-01

346

ARTI Refrigerant Database  

SciTech Connect

The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air- conditioning and refrigeration equipment. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R- 717 (ammonia), ethers, and others as well as azeotropic and zeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents on compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. A computerized version is available that includes retrieval software.

Calm, J.M.

1992-11-09

347

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

348

Magnetic refrigeration for spacecraft systems  

SciTech Connect

Magnetic refrigerators, i.e., those that use the magnetocaloric effect of a magnetic working material in a thermodynamic cycle, offer potentially reliable, and efficient refrigeration over a variety of temperature ranges and cooling powers. A descriptive analysis of magnetic refrigeration systems is performed with particular emphasis on more efficient infrared detector cooling. Three types of magnetic refrigerator designs are introduced to illustrate some of the possibilities.

Barclay, J.A.

1981-01-01

349

Superfluid Stirling refrigerator with a counterflow regenerator  

SciTech Connect

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

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

1992-01-01

350

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...

351

Electrocaloric refrigeration at cryogenic temperatures  

Microsoft Academic Search

Refrigeration utilizing the electrocaloric effect can be produced with no moving parts and thus, promises to be highly reliable. This paper reviews the principles and experimental results on electrocaloric refrigeration, particularly in the 4–15K temperature range. Many electrocaloric materials were studied but none was found with a sufficiently large reversible electrocaloric effect for a practical refrigerator. The largest effects were

Ray Radebaugh; W. N. Lawless; J. D. Siegwarth; A. J. Morrow

1980-01-01

352

Impact of air and refrigerant maldistributions on the performance of finned-tube evaporators with R-22 and R-407C. Final Report  

Microsoft Academic Search

The report presents basic features of the evaporator model, EVAP5M, and simulation results for an evaporator operating with R-22 and R-407C at non-uniform air and refrigerant distributions. EVAP5M was developed under this project to provide a tool for simulating a finned-tube air-to refrigerant evaporator operating with single-component refrigerants and refrigerant mixtures. The tube-by-tube modeling approach allowed for one-dimensional non-uniformity in

Jangho Lee; P. A. Domanski

1997-01-01

353

PERFORMANCE EVALUATION OF A VARIABLE SPEED, MIXED REFRIGERANT HEAT PUMP  

EPA Science Inventory

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

354

Thermophysical-property needs for the environmentally acceptable halocarbon refrigerants  

Microsoft Academic Search

The need for and uses of thermodynamic and transport properties in the selection of working fluids for the vapor compression cycle and in equipment design are reviewed. A list of hydrogen-containing halocarbons, as well as their mixtures, is presented as alternatives to the environmentally harmful, fully halogenated chlorofluorocarbons. These fluids range from well-characterized, widely available refrigerants to materials available only

M. O. McLinden; D. A. Didion

1989-01-01

355

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

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Definitions concerning commercial refrigerators, freezers and refrigerator-freezers...CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and...

2010-01-01

356

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

357

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

358

Education in Helium Refrigeration  

NASA Astrophysics Data System (ADS)

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

Gistau Baguer, G. M.

2004-06-01

359

Education in Helium Refrigeration  

SciTech Connect

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

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

2004-06-23

360

MLAP: a MAC level access protocol for the HFC 802.14 network  

Microsoft Academic Search

Interactive residential broadband\\/multimedia services are expected to be the next main event in the cyberspace experience. The large excess bandwidth (well over 300 MHz) available in today's cable TV (CATV) hybrid fiber\\/coaxial (HFC) plants is an ideal candidate to provide the underlying communications infrastructure for interactive digital services to the home; cable operators that have not yet upgraded their all-coaxial

C. Bisdikian; B. McNeil; R. Norman; R. Zeisz

1996-01-01

361

Choked flow mechanism of HFC134a flowing through short-tube orifices  

Microsoft Academic Search

This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a

Kitti Nilpueng; Somchai Wongwises

2011-01-01

362

The thermal conductivity of liquid 1,1,1,2-tetrafluoroethane (HFC-134a)  

SciTech Connect

The thermal conductivity of HFC 134a was measured in the liquid phase with the polarized transient hot-wire technique. The experiments were performed at temperatures from 213 to 293 K at pressures up to 20 MPa. The data were analyzed to obtain correlations in terms of density and pressure. This study is part of an international project coordinated by the Subcommittee on Transport Properties of Commission I.2 of IUPAC, conducted to investigate the large discrepancies between the results reported by various authors for the transport properties of HFC 134a, using samples of different origin. Two samples of HFC 134a from different sources have been used. The thermal conductivity of the first sample was measured along the saturation line as a function of temperature and the data were presented earlier. The thermal conductivity of the second one, the round-robin sample, was measured as a function of pressure and temperature. These data were extrapolated to the saturation line and compared with the data obtained, previously in order to demonstrate the importance of the sample origin and their real purity. The accuracy of the measurements is estimated to be 0.5%. Finally, the results are compared with the existing literature data.

Gurova, A.N.; Mardolcar, U.V. [Inst. Superior Tecnico, Lisboa (Portugal). Dept. de Fisica; Nieto de Castro, C.A. [Univ. de Lisboa (Portugal)

1997-09-01

363

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

364

EFFECT OF RE-HEATING ON VIABILITY OF A 5-STRAIN MIXTURE OF L. MONOCYTOGENES IN VACUUM-SEALED PKGS OF FRANKFURTERS,COMMERCIALLY PREPARED WITH AND WITHOUT 2.0% POTASSIUM LACTATE, FOLLOWING REFRIGERATED OR FROZEN STORAGE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The purpose of this study was to assess the effect of product formulation and storage times and temperatures on the viability of Listeria monocytogenes after re-heating of frankfurters. Individual links were inoculated with about 8.0 log10 CFU/package of a five-strain mixture of the pathogen, vacuu...

365

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

Code of Federal Regulations, 2013 CFR

...designed to compress and liquefy a specific refrigerant that is remotely located from the refrigerated equipment and consists of 1 or more refrigerant compressors, refrigerant condensers, condenser fans and motors,...

2013-01-01

366

Evaluation of alternative refrigerant—adsorbent pairs for refrigeration cycles  

Microsoft Academic Search

The refrigerant-adsorbent pairs at present preferred for solid-sorption refrigeration cycles are ammonia-carbon, methanol-carbon, ammonia salts and water-zeolite. Porosity tests have been carried out on a range of alternatives, including R32 and butane, as refrigerants and new monolithic carbon adsorbents. The results of fitting to the Dubinin equation and modelling of cycles based on these pairs are presented. Ammonia is still

R. E. Critoph

1996-01-01

367

Discussion of Refrigeration Cycle Using Carbon Dioxide as Refrigerant  

NASA Astrophysics Data System (ADS)

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

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

368

Bayreuth nuclear demagnetization refrigerator  

SciTech Connect

The design, construction, and performance of a Cu nuclear refrigerator are reported. The first nuclear stage (total 275 moles Cu with 104 moles Cu in 8 T) has refrigerated a /sup 195/Pt NMR thermometer in the low-field experimental region to 15 ..mu..K; it can keep experiments below 20 ..mu..K for more than 1 week. It can alternatively precool a second nuclear stage (2 moles Cu in 9 T). Demagnetizing this stage has resulted in a temperature of at most 12 ..mu..K as measured by another /sup 195/Pt NMR thermometer attached to the stage. The details of the thermometry are described and possible origins of the observed internal heat leaks as well as unexpected contributions to the specific heat of the nuclear stages are discussed.

Gloos, K.; Smeibidl, P.; Kennedy, C.; Singsaas, A.; Sekowski, P.; Mueller, R.M.; Pobell, F.

1988-10-01

369

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

370

Compact acoustic refrigerator  

DOEpatents

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

Bennett, G.A.

1991-12-31

371

Dual mixed refrigerant natural gas liquefaction  

Microsoft Academic Search

A process and apparatus is described for liquefying natural gas using two closed cycle, multicomponent refrigerants wherein a low level refrigerant cools and liquefies the gas by indirect heat exchange and a high level refrigerant cools and partially liquefies the low level refrigerant by indirect multistage heat exchange. The high level refrigerant is phase separated in order to use lighter

Y.-N. Liu; J. W. Pervier

1985-01-01

372

Head pressure control system for refrigeration unit  

Microsoft Academic Search

A refrigeration system having a closed refrigerant loop is described comprising: an evaporator; an air cooled condenser; a compressor connected between the evaporator and the condenser; an expansion device connected between the condenser and the evaporator; a receiver for separating gaseous refrigerant and liquid refrigerant prior to the liquid refrigerant entering the expansion device; a pressure regulating means connecting the

ONeal

1988-01-01

373

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

374

Study to determine the existence of an azeotropic R-22 `drop-in` substitute  

SciTech Connect

The reduction in chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) production and the scheduled phase-out of these ozone depleting refrigerants requires the development and determination of environmentally safe refrigerants for use in heat pumps, water chillers, air conditioners, and refrigerators. Azeotropic mixtures are attractive as alternative refrigerants because they behave very nearly as pure materials. A simple correlative scheme that allows one to judge whether or not an azeotrope is likely in a binary refrigerant mixture is discussed. This paper presents laboratory and computer simulation model evaluation of two of the azeotropic refrigerant mixtures which are identified, HFC-134a (1,1,1,2-tetrafluoroethane) with R-C290 (Propane) and HFC-134a with R-600a (Isobutane), in a generic heat pump apparatus. A third azeotropes mixture, HFC-134a with R-C290 (Cyclopropane) is examined by computer simulation only.

Kim, M.S.; Morrison, G.; Mulroy, W.J.; Didion, D.A.

1996-03-01

375

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.

376

A general dynamic simulation model for evaporators and condensers in refrigeration. Part II: simulation and control of an evaporator  

Microsoft Academic Search

A mathematical model of an evaporator based on one-dimensional partial differential equations representing mass conservation, and tube wall energy has been formulated. These equations are then restructured and linked to a program data base of all major refrigerants and refrigerant mixtures. The result is a simulation model of an evaporator that is general and flexible. The model is tested over

N. B. O. L. Pettit; M. Willatzen; L. Ploug-Sørensen

1998-01-01

377

Piezoelectrically-driven Thermoacoustic Refrigerator  

NASA Astrophysics Data System (ADS)

Thermoacoustic refrigeration is an emerging refrigeration technology which does not require any moving parts or harmful refrigerants in its operation. This technology uses acoustic waves to pump heat across a temperature gradient. The vast majority of thermoacoustic refrigerators to date have used electromagnetic loudspeakers to generate the acoustic input. In this thesis, the design, construction, operation, and modeling of a piezoelectrically-driven thermoacoustic refrigerator are detailed. This refrigerator demonstrates the effectiveness of piezoelectric actuation in moving 0.3 W of heat across an 18 degree C temperature difference with an input power of 7.6 W. The performance characteristics of this class of thermoacoustic-piezoelectric refrigerators are modeled by using DeltaEC software and the predictions are experimentally validated. The obtained results confirm the validity of the developed model. Furthermore, the potential of piezoelectric actuation as effective means for driving thermoacoustic refrigerators is demonstrated as compared to the conventional electromagnetic loudspeakers which are heavy and require high actuation energy. The developed theoretical and experimental tools can serve as invaluable means for the design and testing of other piezoelectrically-driven thermoacoustic refrigerator configurations.

Chinn, Daniel George

378

Simulation of the Energy Saver Refrigeration System.  

National Technical Information Service (NTIS)

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 ...

H. R. Barton J. E. Nicholls G. T. Mulholland

1981-01-01

379

Energy Savings Potential for Commercial Refrigeration Equipment.  

National Technical Information Service (NTIS)

The study examined commercial refrigeration equipment (supermarkets, refrigerated vending machines, beverage merchandisers, reach-in and walk-in refrigerators and freezers, and ice machines). Baseline energy use, potential energy savings, and the economic...

D. Westphalen R. A. Zogg A. F. Varone M. A. Foran

1996-01-01

380

46 CFR 154.702 - Refrigerated carriage.  

Code of Federal Regulations, 2012 CFR

...capacity requirements for the essential purposes and the refrigeration cooling water. (e) Each refrigeration system must use refrigerants that are compatible with the cargo and, for cascade units, with each other. (f) The pressure of the heat...

2012-10-01

381

46 CFR 154.702 - Refrigerated carriage.  

Code of Federal Regulations, 2011 CFR

...capacity requirements for the essential purposes and the refrigeration cooling water. (e) Each refrigeration system must use refrigerants that are compatible with the cargo and, for cascade units, with each other. (f) The pressure of the heat...

2011-10-01

382

Sorption Compressor/Mechanical Expander Hybrid Refrigeration.  

National Technical Information Service (NTIS)

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 expansi...

J. A. Jones M. Britcliffe

1987-01-01

383

Refrigerator-freezer energy testing with alternative refrigerants  

SciTech Connect

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

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

1989-01-01

384

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

385

Recent progress in magnetic refrigeration studies  

NASA Astrophysics Data System (ADS)

The results of two investigations of magnetic refrigeration above 15 K are discussed. One was initiated to improve the refrigeration characteristics of a system for the Carnot magnetic refrigerator, and the other to study the Ericsson magnetic refrigerator. It was found that the refrigeration range could be expanded by using a new magnetic material, Dy3Al5O12, instead of the usual Gd3Ga5O12, as the refrigerant in a reciprocating Carnot magnetic refrigerator. A method was developed to make this refrigerant suitable for the ideal Ericsson cycle.

Hashimoto, T.; Yazawa, T.; Li, R.; Kuzuhara, T.; Matsumoto, K.

386

Heat transfer of oil-contaminated HFC134a in a horizontal evaporator  

Microsoft Academic Search

The introduction of chlorine-free refrigerants to the market requires experimental investigations of their behaviour in heat pumps and refrigerators. One particular area of interest is the effect of the new oils on the heat transfer in evaporators and condensers. Oil can either increase or decrease the heat transfer coefficient. This paper presents the results from an experimental investigation of the

K Hambraeus

1995-01-01

387

Distributed laser refrigeration.  

PubMed

A 250-mum-diameter fiber of ytterbium-doped ZBLAN (fluorine combined with Zr, Ba, La, Al, and Na) has been cooled from room temperature. We coupled 1.0 W of laser light from a 1013-nm diode laser into the fiber. We measured the temperature of the fiber by using both fluorescence techniques and a microthermocouple. These microthermocouple measurements show that the cooled fiber can be used to refrigerate materials brought into contact with it. This, in conjunction with the use of a diode laser as the light source, demonstrates that practical solid-state laser coolers can be realized. PMID:18364823

Rayner, A; Hirsch, M; Heckenberg, N R; Rubinsztein-Dunlop, H

2001-10-20

388

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.

389

Quantum Absorption Refrigerator  

NASA Astrophysics Data System (ADS)

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

Levy, Amikam; Kosloff, Ronnie

2012-02-01

390

Condensation of refrigerants flowing inside smooth and corrugated tubes  

SciTech Connect

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

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

1995-07-01

391

Magnetocaloric effect and magnetic refrigeration  

Microsoft Academic Search

The phenomenon of the magnetocaloric effect along with recent progress and the future needs in both the characterization and exploration of new magnetic refrigerant materials with respect to their magnetocaloric properties are discussed. Also the recent progress in magnetic refrigerator design is reviewed.

Vitalij K. Pecharsky; Karl A. Gschneidner Jr

1999-01-01

392

MFTF-B refrigerator analysis  

SciTech Connect

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

NONE

1995-02-10

393

Superinsulation in refrigerators and freezers  

Microsoft Academic Search

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.

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

1998-01-01

394

Heat recovery in refrigeration: I  

Microsoft Academic Search

Considers heat recovery methods, hot gas reclaim, load calculations, and piping (series and parallel) considerations with regard to refrigeration systems. Presents diagrams showing early heat recovery system; discharge gas heat recovery system with heat recovery condenser below main condenser; discharge gas heat recovery system parallel hookup; and discharge gas heat recovery system with highside float control. Explains that all refrigeration

1983-01-01

395

Semiconductor-based optical refrigerator  

DOEpatents

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

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

2002-01-01

396

Comparative study of the performance of an ejector refrigeration cycle operating with various refrigerants  

Microsoft Academic Search

Ejector refrigeration systems have attracted many research activities in recent years. These systems traditionally operate with water as refrigerant with low COP values. Other refrigerants commonly used in mechanical vapour compression cycles may provide better performance for ejector refrigeration cycles. Eleven refrigerants, including water, halocarbon compounds (CFCs, HCFCs and HFCs), a cyclic organic compound, and an azeotrope, are chosen as

Da-Wen Sun

1999-01-01

397

Simulation of the Energy Saver refrigeration system  

Microsoft Academic Search

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

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

1981-01-01

398

Modeling supermarket refrigeration energy use and demand  

Microsoft Academic Search

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

M. H. Blatt; M. K. Khattar; D. H. Walker

1991-01-01

399

Analyses and syntheses of ferroelectric refrigeration ceramics  

Microsoft Academic Search

Cryogenic refrigeration could be realized by using the electrocaloric effect (i. e. inverse pyroelectric effect) of ferroelectric materials. Recent progresses implied that ferroelectric refrigeration may be a possible new technique of cryogenic refrigeration operated near room temperature. The analyses and syntheses of ferroelectric refrigeration ceramics of PMN-PT system are presented in this paper

D. Q. Xiao; B. Yang; S. Q. Peng; Y. C. Wang; J. G. Zhu

1997-01-01

400

Development of jt Coolers Operating at Cryogenic Temperatures with Nonflammable Mixed Refrigerants  

NASA Astrophysics Data System (ADS)

Throttle cycle coolers, operating with mixed refrigerants have been already used at refrigeration temperatures down to 70 K. An industrial single-stage, oil lubricated compressor can be used to provide both, a relatively low cost and long operational time. Application of nonflammable mixed refrigerants is important for safety, transportation, service and maintenance. However, it is more difficult to provide a required refrigeration performance and long-term reliability due to properties of nonflammable components. The paper presents experimental and modeling data for single-stage coolers operating in a temperature range of 80 to 150 K. The nonflammable components were selected to develop mixed refrigerants for the desired temperature ranges. A gas refrigerant supply technology is used for a single-stage cooler design. The minimal achievable temperature is restricted by the freezing point of the mixture. Selected gas refrigerant technology restricts the maximal refrigeration capacity. However, it allows a compromise between stable, long-term reliable operation and simplicity of equipment design. Stability of operation of small-scale, highly reliable coolers has been proven by the data accumulated over more than one year of testing.

Khatri, A.; Boiarski, M.

2008-03-01

401

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

402

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

403

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 ...

404

Saturated liquid densities and bubble-point pressures of the binary HFC 152a+HCFC 142b system  

NASA Astrophysics Data System (ADS)

Forty-eight sets of the saturated liquid densities and bubble-point pressures of the binary HFC 152a + HCFC 142b system were measured with a magnetic densimeter coupled with a variable-volume cell. The measurements obtained at four compositions, 20, 40, 60, and 80 wt%, of HFC 152a cover a range of temperatures from 280 to 400 K. The experimental uncertainties in temperature, pressure, density, and composition were estimated to be within ±15mK, ±20kPa, ±0.2%, and between -0.14 and ±0.01 wt% HFC 152a (-0.01 and + 0.14 wt% HCFC 142b), respectively. The purities of the samples were 99.9 wt% for HFC 152a and 99.8 wt% for HCFC 142b. A binary interaction parameter, k ij , in the Peng-Robinson equation of state was determined as a function of temperature for representing the bubble-point pressures. On the other hand, two constant binary-interaction parameters, k ij and l ij , were introduced into the mixing rule of the Hankinson-Brobst-Thomson equation for representing the saturated liquid densities.

Maezawa, Y.; Widiatmo, J. V.; Sato, H.; Watanabe, K.

1991-11-01

405

Refrigerator-freezer energy testing with alternative refrigerants  

SciTech Connect

As a result of the Montreal Protocol (UNEP 1987) that limits the production of ozone-depleting refrigerants, manufacturers are searching for alternatives to replace the R12 that is presently used in residential refrigerator-freezers. Before an alternative can be selected, several issues must resolved. Among these are energy impacts, system compatibility, cost, and availability, In an effort to determine the energy impacts of some of the alternatives, energy consumption tests were performed in accordance with section 8 of the Association of Home Appliance Manufacturers (AHAM) standard for household refrigerators and household freezers (AHAM 1985). The results are presented for an 18 ft{sup 3} (0.51 m{sup 3}), top mount refrigerators-freezer with a static condenser using the following refrigerants: R 12, R500, R12/dimethylether (DME), R22/R142b, and R134a. Conclusions from the AHAM test are that R500 and R12/DME have a reduced energy consumption relative to R12 when replaced in the test unit with no modifications to the refrigeration system. Run times were slightly lower than R12 for both refrigerants, indicating a higher capacity. While the R134a and R22/R142b results were less promising (6.8% and 8.5% higher energy consumption, respectively), changes to the refrigeration system, such as a different capillary tube or compressor, may improve their performance. It is noted that the test results are only an initial step in determining a replacement for R12.

Sand, J.R. (Oak Ridge National Lab., Oak Ridge, TN (US)); Vineyard, E.A.; Sand, J.R.

1989-01-01

406

Performance evaluation of a variable-speed, mixed-refrigerant heat pump  

SciTech Connect

The performance of an innovative heat pump, equipped with a distillation column to shift the composition of a zeotropic refrigerant mixture, was evaluated. The results of the DoE rating tests and seasonal energy calculations are reported with the main cycle refrigerant compositions. No composition shifting of the circulating refrigerant mixture was observed. To demonstrate the potential value of composition shifting, an ideal vapor compression cycle computer program was used to predict what the system performance would have been had composition shifting occurred. Seasonal energy usage calculations based on the computer predictions demonstrated that the effect of composition shifting on HSPF was very small, increasing slightly with climate zone. However, the savings in auxiliary heat was found to be substantial. In cooling mode, computer predictions showed pure R22 to have a SEER approximately two percent higher than a mixture of 20% R13B1 and 80% R22 by weight.

Rothfleisch, P.I.; Didion, D.A.

1991-06-01

407

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

SciTech Connect

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

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

2007-10-15

408

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

SciTech Connect

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

Dennis Cartlidge; Hans Schellhase

2003-07-31

409

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

410

16 CFR 305.11 - Labeling for refrigerators, refrigerator-freezers, freezers, dishwashers, clothes washers, water...  

Code of Federal Regulations, 2010 CFR

...appliances. (ii) For refrigerators, refrigerator-freezers, and freezers...range based only on refrigerator models of similar capacity...fueled by [natural gas, oil, propane, or...appendix D4) and heat pump water...

2009-01-01

411

16 CFR 305.11 - Labeling for refrigerators, refrigerator-freezers, freezers, dishwashers, clothes washers, water...  

Code of Federal Regulations, 2010 CFR

...appliances. (ii) For refrigerators, refrigerator-freezers, and freezers...range based only on refrigerator models of similar capacity...fueled by [natural gas, oil, propane, or...appendix D4) and heat pump water...

2010-01-01

412

Superinsulation in refrigerators and freezers.  

National Technical Information Service (NTIS)

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 t...

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

1998-01-01

413

Experimental exposure to 1,1,1,3,3-pentafluoropropane (HFC-245fa): uptake and disposition in humans.  

PubMed

The aim of this study was to determine the toxicokinetics of inhaled 1,1,1,3,3-pentafluoropropane (HFC-245fa) in humans. Five healthy volunteers of each sex were exposed in random order to 0, 100, or 300 ppm HFC-245fa for 2 h at light exercise (50 W) in an exposure chamber. Capillary blood, urine, and exhaled air were sampled up to 22 h postexposure and analyzed for HFC-245fa. In addition, the metabolites fluoride, 3,3,3-trifluoropropionic acid (TFPA), and trifluoroacetic acid (TFAA) were analyzed in urine. Symptoms of irritation and central nervous system effects were rated in visual analogue scales. Various biochemical (aspartate-amino transferase, alanine-amino transferase, alkaline phosphate, glutamyl transferase, urate, creatine kinase [CK], and CK muscle brain) and inflammatory markers (serum amyloid A protein, fibrinogen, D-dimer, C-reactive protein, and interleukin-6) in plasma were analyzed. The initial increase in blood was fast and an apparent steady state was reached within a few minutes at both exposure levels. The postexposure decrease in blood was equally fast and parallel to that in exhaled air. Only minor amounts of unchanged HFC-245fa were excreted in breath (0.7% of inhaled) and urine (0.001%). The observed time courses in blood and breath agreed reasonably well those obtained by physiologically based pharmacokinetic (PBPK) modeling. The PBPK simulations indicate a relative uptake during exposure of 2.1%. TFPA was not detected in urine, and no increase in TFAA or fluoride above background was seen, suggesting little or no metabolism, the calculated minimum detectable metabolism being 0.001% of the inhaled amount. The symptom ratings revealed no HFC-245fa-related effects. None of the biochemical markers was affected. The changes in inflammatory markers, some of which are statistically significant, were not consistent with an inflammatory response. PMID:19915083

Ernstgård, Lena; Andersen, Melvin; Dekant, Wolfgang; Sjögren, Bengt; Johanson, Gunnar

2009-11-13

414

Dipole moments of seven refrigerants  

Microsoft Academic Search

This paper reports that Dielectric constant measurements have been performed on seven refrigerants in the gaseous state over the range 305-415 K in order to determine their dipole moments. Four of the refrigerants have temperature-independent moments: R123, [mu] -= 1.358 [plus minus] 0.019 D; R141b, [mu] = 2.014 [plus minus] 0.018 D; R22, [mu] = 1.458 [plus minus] 0.003 D;

Christopher W. Meyer; Graham Morrison

1991-01-01

415

Thermoelectric refrigerator for gas analyzer  

Microsoft Academic Search

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

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

1987-01-01

416

Noise and distortions limitations in the design of HFC CATV systems  

NASA Astrophysics Data System (ADS)

The paper deals with HFC CATV systems. System parameters determinative in obtaining the desired carrier-to-noise ratio (CNR) and acceptable nonlinear distortions are considered. Formulae for the gain and the maximum number of RF amplifiers in the longest coaxial trunk line are developed. A mathematical model of the optical channel is suggested that makes it possible for the signal minimum level at the optical receiver input to be calculated if the value of CNR and the number of TV channels transmitted are known. Analytical expressions to determine the RF signal voltage in the input and output of the optical line are given that take into consideration the nonlinear distortions in the laser transmitter, the number of TV channels and the losses within the optical fiber and passive elements. Experimental results are given to illustrate the application of the formulae in the design of a HFS system section.

Dobrev, Dobri; Jordanova, Lidia

2006-04-01

417

Refrigerant recycling apparatus, method and system  

SciTech Connect

A refrigerant recycling apparatus for recovery and purification of refrigerant is described comprising: (a) an input conduit system for connecting a refrigerant source to the refrigerant recycling apparatus; (b) a first disposable filter capable of removing moisture and particulates from the refrigerant, said disposable filter being located such that the filter is easily accessible for service; (c) a primary heat exchanger configured so as to provide heat to the refrigerant thereby causing the refrigerant to be vaporized; (d) a secondary heat exchanger for further heating of the refrigerant to further assist in vaporization of the refrigerant; (e) an expansion valve located prior in line to said primary and secondary heat exchangers for controlling the flow of the refrigerant and reducing the pressure of the refrigerant, thereby allowing the refrigerant to expand to a predominantly gaseous state; (f) a separator for removing oil from the refrigerant; (g) a compressor pump having a vacuum producing inlet and a pressure producing outlet, the pump being a hermetically sealed, lubricated-for-life positive displacement pump; (h) a condenser for cooling the refrigerant; (i) a second disposable filter for removing moisture, acids, and other particulates from the refrigerant passing there through, said disposable filter being located in an area easily accessible for servicing; (j) an interconnecting conduit system for interconnecting the input conduit system, the first and second disposable filters, the heat exchangers, the compressor pump, the condenser, the expansion valve, and the refrigerant source; (k) a moisture indicator located after the second disposable filter, for measuring the degree of moisture present within the refrigerant after the refrigerant has flowed through the second disposable filter.

Christensen, J.P.; Gordon, R.F.

1993-07-13

418

The influence of lubricant viscosity on the wear of hermetic compressor components in HFC134a environments  

Microsoft Academic Search

Hydrofluorocarbons (HFCs) are transitional refrigerants being used in the wake of international agreements aimed at developing more environmentally acceptable refrigerants. An evaluation of the tribological characteristics relating to the conforming contact between the die-cast aluminium alloy connecting rod and the hardened steel gudgeon pin of a reciprocating compressor is presented. An experimental investigation was carried out on liquid\\/vapour refrigeration systems.

C Ciantar; M Hadfield; A. M Smith; A Swallow

1999-01-01

419

Top-down Estimation of Emission Strengths of Major Anthropogenic Halocarbons from China Using High-frequency Measurements with HCFC-22/HFC-23 as Tracers  

NASA Astrophysics Data System (ADS)

In this study we present calculations of Chinese emissions of most major anthropogenic halocarbon species, including CFCs (CFC-11, CFC-12), HCFCs (HCFC-22, HCFC-141b, HCFC-142b), HFCs (HFC-134a, HFC-125, HFC-152a, HFC-23, HFC-143a, HFC-32), H-1211, PFCs(CF4, PFC-116, PFC-218) and solvents (CH3Cl, CH2Cl2, CHCl3, CCl4), using data from high-frequency measurements made with a automated GC-MSD instrument (“Medusa”) operated at Gosan station (126°E, 33°N, Jeju Island, Korea) under the Advanced Global Atmospheric Gases Experiment(AGAGE) network. China is one of the top consumers of HCFC-22 in the world, and enhancement of HCFC-22 seem to correlate well with enhancements in most other species, indicative of its wide use. HFC-23 is special in that most its emission occur during HCFC-22 production (1~4% of HCFC-22 production). Considering that China is one of the world’s largest producers of HFC-23, pollution events of HFC-23 indicate influence of specific industrial regions in the vicinity of HCFC-22 production plants. Using measurements during November 2007 ~ December 2008, we analyze pollution occurrence and magnitudes of HCFC-22 data based on the AGAGE pollution algorithm, then use three-dimensional air mass trajectory models to separate pollution events of Chinese origin. From these Chinese pollution events, we analyze the concurrent episodes of pollution in other species to find a enhancement ratio against HCFC-22, which is converted to actual emission rates by multiplying independently calculated values for HCFC-22 emission rates. Similar methodology is used with HFC-23 for a subset of species that show good correlation with both HCFC-22 and HFC-23 enhancements. Our methodology provide a means to assess Chinese emissions of almost all important halocarbons, and the coupled tracer approach provides the means to test the validity of our calculations. Comparing our results to both top-down and bottom-up emissions estimates performed for China as well as global, the importance of Chinese emissions to the global budget can be clearly seen with substantial emissions of CFCs and HCFCs coming from China. While developed countries have been overall faster in adopting HFCs resulting in relatively less total emissions in China, a number of compounds show large Chinese emissions, which may be largely underestimated in current bottom-up studies.

Kim, K.; Kim, J.; Li, S.; Muhle, J.; Stohl, A.; Kim, S.; Lee, G.; Weiss, R. F.

2009-12-01

420

46 CFR 151.40-11 - Refrigeration systems.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 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...

2009-10-01

421

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

422

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

423

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

424

Search for Alternative Refrigerants: A Molecular Approach.  

National Technical Information Service (NTIS)

The impending production limitation on the fully halogenated CFC refrigerants is causing an intense search for possible substitutes. This study reviews the historical development of the CFC refrigerants and the relationship between molecular structure and...

D. A. Didion M. O. McLinden

1988-01-01

425

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...

426

A review of absorption refrigeration technologies  

Microsoft Academic Search

This paper provides a literature review on absorption refrigeration technology. A number of research options such as various types of absorption refrigeration systems, research on working fluids, and improvement of absorption processes are discussed.

Pongsid Srikhirin; Satha Aphornratana; Supachart Chungpaibulpatana

2001-01-01

427

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, ...

428

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

429

Liquid Helium Refrigerator for Testing Superconducting System.  

National Technical Information Service (NTIS)

In the next several years, various superconducting test transmission cables will probably be built and tested. Each test cable will require a medium sized helium refrigerator. To avoid unnecessary duplication of refrigeration systems required for testing,...

H. Morihara J. W. Terbot

1975-01-01

430

Performance comparison of magnetic refrigeration cycles.  

National Technical Information Service (NTIS)

Magnetic refrigeration has been used for cryogenic cooling at temperatures near absolute zero for many years. In these cases, a single-step adiabatic demagnetization method that does not provide continuous refrigeration is commonly used. The possibilities...

F. C. Chen G. L. Chen R. W. Murphy V. C. Mei

1990-01-01

431

Theoretical study of a transcritical ejector refrigeration cycle with refrigerant R143a  

Microsoft Academic Search

In this paper, a transcritical ejector refrigeration cycle (TERC) using refrigerant R143a as working fluid is proposed to improve the performance of the ejector refrigeration systems driven by low-grade thermal energy. This method adopts an adequate combination of thermal and mechanical energy through the operation of the transcritical process for generator to enhance the performance of the conventional ejector refrigeration

Jianlin Yu; Zhenxing Du

2010-01-01

432

Heat recovery in refrigeration: II  

SciTech Connect

Evaluates refrigeration systems with regard to controls, hot water recovery units, packaged condensing units, and energy efficiency. Most present day controls are microprocessors that programmed to react to a multiplicity of conditions such as outdoor temperature, condensing pressure, space humidity and time of day. Hot water heat recovery units are heat exchangers, usually of the double tube counterflow type, which are connected on the refrigerant side to the compressor discharge. Since the most effective energy saving method in refrigeration systems is operation at reduced head pressure, many commercial packaged systems have been redesigned to offer more condensing capacity, which means either increased air cooled condenser surface or the option to add evaporative cooling of the condenser during the summer season. Another more obvious option is a water cooled booster condenser which is placed in operation at times when condensing pressure exceeds a predetermined limit, or a complete changeover to water cooled condensing.

Nussbaum, O.J.

1983-02-01

433

Thermophysical-property needs for the environmentally acceptable halocarbon refrigerants  

NASA Astrophysics Data System (ADS)

The need for and uses of thermodynamic and transport properties in the selection of working fluids for the vapor compression cycle and in equipment design are reviewed. A list of hydrogen-containing halocarbons, as well as their mixtures, is presented as alternatives to the environmentally harmful, fully halogenated chlorofluorocarbons. These fluids range from well-characterized, widely available refrigerants to materials available only by custom synthesis about which very little is known. Data priorities for these fluids are presented; most essential are critical point, vapor pressure, liquid density, ideal-gas heat capacity, and vapor p-V-T data. A critical need exists for these data on a number of candidate working fluids in order not to lose the opportunity to select the best set of future refrigerants.

McLinden, M. O.; Didion, D. A.

1989-05-01

434

Description of the vapor–liquid equilibrium in binary refrigerant\\/lubricating oil systems by means of an extended Flory–Huggins model  

Microsoft Academic Search

In the present work, the extended Flory–Huggins equation is applied to describe the vapor–liquid equilibrium in binary mixtures usually used in refrigerating cycle machines and constituted by a fluorinated refrigerant (CFC) and a lubricating oil.With the purpose of testing the model, some isothermal measurements of equilibrium pressure have been carried out for mixtures with different CFC compositions in oil related

R Tesser; E Musso; M Di Serio; G Basile; E Santacesaria

1999-01-01

435

Application of the PFGC-MES equation of state to refrigerants  

SciTech Connect

The parameters from group contribution (PFGC) equation of state, as used by Moshfeghian, Erbar, and Shariat (PFGC-MES), is used to describe the thermodynamic behavior of 20 refrigerants. These refrigerants include pure halogenated compounds, azotropic mixtures of halogenated compounds, and ammonia. The parameters were determined by simultaneously fitting data for vapor pressure, saturated vapor and liquid volumes, and heats of vaporization using a standard nonlinear analysis program. All parameters for the 20 refrigerants are reported, as are the deviations between predicted and experimental data. These deviations are compared to those from the Soave-Redlich-Kwong equation state. The predicted and experimental {ital K} values for two binary mixtures of the pure halogenated compounds are also compared.

Moshfeghian, M.; Shariat, A. (Dept. of Chemical Engineering, Shiraz Univ., Shiraz (IR)); Erbar, J.H.; Erbar, R.C. (School of Chemical Engineering, Oklahoma State Univ., Stillwater, OK (US))

1989-12-01

436

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

437

Refrigeration System which Compensates for Heat Leakage.  

National Technical Information Service (NTIS)

A refrigeration system/cycle includes two or more refrigeration stages, in which one or more of the warmer stages provide(s) cooling to partially compensate for heat leakage that would otherwise leak to the colder stage(s). The refrigeration system includ...

D. S. Beck

2004-01-01

438

Simulation of the energy saver refrigeration system  

Microsoft Academic Search

An interactive, software simulator is described as has been developed to calculate the refrigeration available from the energy saver refrigeration system, Fermilab Energy Saver. The refrigeration system simulator incorporates models of the components which have been developed to quantitaviley describe changes in system performance. The simulator output is presented in a real-time display which has been used to search for

H. R. Barton; G. T. Mullholland; J. E. Nicholls

1982-01-01

439

Ternary Dy-Er-Al magnetic refrigerants  

SciTech Connect

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

440

46 CFR 147.90 - Refrigerants.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Refrigerants. 147.90 Section 147.90 Shipping...Requirements for Particular Materials § 147.90 Refrigerants. (a) Only refrigerants listed in ANSI/ASHRAE 34-78 may be...

2012-10-01

441

46 CFR 147.90 - Refrigerants.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Refrigerants. 147.90 Section 147.90 Shipping...Requirements for Particular Materials § 147.90 Refrigerants. (a) Only refrigerants listed in ANSI/ASHRAE 34-78 may be...

2011-10-01

442

Method and apparatus for desuperheating refrigerant  

SciTech Connect

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

443

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

444

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

445

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

446

Absorption refrigeration: cooling with hot water  

Microsoft Academic Search

The absorption cycle is a process by which refrigeration effect is produced through the use of two fluids and some quantity of heat input, rather than electrical input as in the more familiar vapor compression cycle. Both vapor compression and absorption refrigeration cycles accomplish the removal of heat through the evaporation of a refrigerant at a low pressure and the

Rafferty

1984-01-01

447

Methods development for measuring and classifying flammability/combustibility of refrigerants. Final report  

SciTech Connect

Because of concerns for the effect that chlorofluorocarbon (CFC) fluids currently in use as refrigerants have on the environment, the refrigeration industry is considering the use of natural refrigerants, many of which are potentially flammable. In some cases, these flammable fluids may result in the least environmental damage when considering ozone depletion, global warming, efficiency, and photochemical reactivity. Many potentially flammable fluids have been proven to be effective when used either by themselves or as a part of a binary or ternary mixture. However, despite favorable initial test results, these fluids may not be acceptable to the general public if questions of safety cannot be adequately addressed. Significant research is being conducted to investigate the flammability of these materials. The purpose of this project is to experimentally determine the impact and variability of eleven different parameters which may affect flammability and/or combustibility of refrigerants and refrigerant blends, as a function of composition and test conditions, and to develop a better understanding of methods and conditions to measure the flammability of refrigerants. The refrigerants used in this study are being considered as new refrigerants and reviewed published data on these materials is scarce. The data contained herein should not be considered complete and should be used only to make relative comparisons of the impacts of the test parameters, not to represent the flammability characteristics of the materials. This report documents Task 3 of the test program. During Task 1, technical literature was thoroughly reviewed and a database of available documents was constructed. During Task 2, the test plan for this task was written. The goals of Task 3 are to investigate the flammability characteristics of selected blends of refrigerants R32, R134a, and R125 using an existing explosion sphere and a newly-constructed ASTM E681 apparatus.

Heinonen, E.W.; Tapscott, R.E.; Crawford, F.R. [Univ. of New Mexico, Albuquerque, NM (United States)

1994-12-01

448

On the temperature distribution in the counter flow heat exchanger with multicomponent non-azeotropic mixtures  

Microsoft Academic Search

The influence of mixture composition on the temperature distribution in the counter flow heat exchanger used in mixture Joule–Thomson refrigerators is investigated in this paper. A perfect heat capacity matching between the supply and the return streams can be achieved by optimizing the mixture composition. The deeper reason is that in two-phase state the latent heat makes a very important

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

2002-01-01

449

Refrigeration and space cooling unit  

Microsoft Academic Search

This invention embodies improvements in evaporative type refrigeration and space cooling units, both as to energy conservation and efficiency and economy of operation. It utilizes the new abentropic principle as set forth in my U.S. Pat. No. 4, 109,470, which demonstrates that the energy of the latent heat vapor is potential energy and need not be discarded as is done

1980-01-01

450

Vapor-liquid equilibria for hydrogen fluoride + difluoromethane, + 1,1,1,2-tetrafluoroethane, and + 1-chloro-1,2,2,2tetrafluoromethane at 283.3 and 298.2 K  

Microsoft Academic Search

The production of refrigerants involves the separation of multicomponent mixtures containing hydrogen fluoride, hydrogen chloride, and various chlorinated and fluorinated hydrocarbons. Therefore, it is essential to known the phase behavior of these mixtures. Isothermal vapor-liquid equilibria for hydrogen fluoride (HF) + difluoromethane (HFC-32), HF + 1,1,1,2-tetrafluoroethane (HFC-134a), and HF + 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) were measured by the P-T-x method at 283.3

J. Lee; H. Kim; J. S. Lim; J. D. Kim; Y. Y. Lee

1996-01-01

451

Direct condensation refrigerant recovery and restoration system  

SciTech Connect

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

Grant, D.C.H.

1992-03-10

452

Refrigeration systems for low-temperature processes  

SciTech Connect

Refrigeration systems are common in processes related to the petroleum-refining, petrochemical and chemical industries. The refrigeration effect can be achieved by using one of the following cycles; (a) vapor compression (reversed Carnot), (b) expansion (reversed Brayton), (c) absorption, and (d) steam jet (water-vapor compression). All of these cycles have been used successfully in industrial refrigeration, but the majority of installations use vapor compression. This paper discusses only the reversed Carnot cycle. The discussion is based on mathematical analysis of thermodynamic process. It is presented under headings - thermodynamics of cycles; vapor-compression cycle; actual refrigeration system; single-stage system; two-stage system; three-stage system; effect of condensing medium; refrigerated subcooling; refrigerant for reboiling; refrigerant cascading. 3 refs.

Mehra, Y.R.

1982-07-12

453

Head pressure control system for refrigeration unit  

SciTech Connect

A refrigeration system having a closed refrigerant loop is described comprising: an evaporator; an air cooled condenser; a compressor connected between the evaporator and the condenser; an expansion device connected between the condenser and the evaporator; a receiver for separating gaseous refrigerant and liquid refrigerant prior to the liquid refrigerant entering the expansion device; a pressure regulating means connecting the compressor to the receiver for automatically maintaining the pressure in the receiver and the condenser in cool ambient conditions; a means connecting the outlet of the condenser to the receiver, including a check valve permitting flow from the condenser into the top of the receiver; a bypass means for diverting sub-cooled liquid refrigerant from the condenser to the expansion device, and a liquid outlet from the receiver extending downwardly from the receiver and interconnected to the bypass means at an elevation below the receiver whereby a static pressure heads of liquid refrigerant is present in the bypass means.

O'Neal, A.

1988-04-05

454

Storage tank scale for a refrigerant recovery system  

SciTech Connect

This patent describes a refrigerant recovery system. It includes a refrigerant storage container, means for withdrawing refrigerant from a refrigeration system and feeding such refrigerant to the container for storage, a scale supporting the container for supplying an electrical signal to indicate impending overfill of the container, and means for directing the electrical signal to the refrigerant-withdrawing means to terminate operation of the refrigerant-withdrawing means when the scale indicates impending overfill of the container.

Punches, R.J.; Murray, G.P.; Shirley, R.D.

1989-11-07

455

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

456

Uptake and disposition of 1,1-difluoroethane (HFC-152a) in humans.  

PubMed

The aim of this study was to determine the toxicokinetics of inhaled 1,1-difluoroethane (HFC-152a) in humans. Healthy volunteers were exposed to 0, 200 or 1000 ppm 1,1-difluoroethane for 2h at light exercise in an exposure chamber. Capillary blood, urine and exhaled air were sampled up to 22 h post-exposure and analyzed for 1,1-difluoroethane. Fluoride and other potential metabolites were analyzed in urine. Symptoms of irritation and central nervous system effects were rated and inflammatory markers were analyzed in blood. Within a few minutes of exposure to 200 and 1000 ppm, 1,1-difluoroethane increased rapidly in blood and reached average levels of 7.4 and 34.3 ?M, respectively. The post-exposure decreases in blood were fast and parallel to those in exhaled air. The observed time courses in blood and breath agreed well with those obtained with the PBPK model. The PBPK simulations indicate a net uptake during exposure to 1000 ppm of 6.6 mmol (6.7%) which corresponds to the amount exhaled post-exposure. About 20 ?mol excess fluoride (0.013% of inhaled 1,1-difluoroethane on a molar basis) was excreted in urine after exposure to 1000 ppm, compared to control. No fluorine-containing metabolites were detected in urine. Symptom ratings and changes in inflammatory markers revealed no exposure-related effects. PMID:22155657

Ernstgård, Lena; Sjögren, Bengt; Dekant, Wolfgang; Schmidt, Tobias; Johanson, Gunnar

2011-12-04

457

Synchronized discrete multitone: a bandwidth-efficient solution for the upstream channel of an HFC system  

NASA Astrophysics Data System (ADS)

Discrete multitone (DMT) has been accepted as a very effective modulation technique for point-to-point transmission on a channel whose SNR is highly frequency-dependent, and it has been adopted by ANSI as the standard for ADSL [up to 7 Mbit/s on unshielded twisted- pair (UTP)]. Synchronized DMT (SDMT), a variation of DMT for multipoint-to-point transmission, will be proposed to the ATIS committee T1E1.4 for VDSL (up to 51.8 Mbit/s on hybrid fiber/UTP), and to the IEEE committee 802.14 for the upstream channel of an HFC system. This paper describes the method of synchronization, which allows the efficient combination of signals from multiple transmitters without the use of guard bands in either the frequency- or time-domain. It also describes a protocol for controlling access to the shared channel by these transmitters, which may have widely varying needs for data rates and formats.

Bingham, John A.

1995-11-01

458

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

PubMed

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

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

2003-02-15

459

Method and apparatus for recovering and purifying refrigerant  

SciTech Connect

This patent describes a method for recovering compressible refrigerant from a refrigeration system, and, delivering the recovered refrigerant to a refrigeration storage means. It comprises withdrawing refrigerant from a refrigeration system; compressing the withdrawn refrigerant in a compressor to form a high pressure gaseous refrigerant; condensing the high pressure gaseous refrigerant to form liquid refrigerant; delivering the liquid refrigerant to the storage means; determining the pressure ratio across the compressor; monitoring the determined pressure ratio; stopping the withdrawal of refrigerant from the refrigeration system when the monitored pressure ratio exceeds a predetermined value; withdrawing refrigerant from the storage means; compressing the refrigerant withdrawn from the storage means in the same compressor used to compress refrigerant withdrawn from the refrigeration system; condensing the compressed refrigerant withdrawn from the storage means; expanding the condensed refrigerant withdrawn from the storage means; expanding the condensed refrigerant withdrawn from the storage means; delivering the expanded refrigerant withdrawn from the storage means back to the storage means to thereby cool the storage means.

Paige, L.E.; Ripka, C.D.

1992-07-07

460

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

461

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

462

Stability of split Stirling refrigerators  

NASA Astrophysics Data System (ADS)

In many thermal systems spontaneous mechanical oscillations are generated under the influence of large temperature gradients. Well-known examples are Taconis oscillations in liquid-helium cryostats and oscillations in thermoacoustic systems. In split Stirling refrigerators the compressor and the cold finger are connected by a flexible tube. The displacer in the cold head is suspended by a spring. Its motion is pneumatically driven by the pressure oscillations generated by the compressor. In this paper we give the basic dynamic equations of split Stirling refrigerators and investigate the possibility of spontaneous mechanical oscillations if a large temperature gradient develops in the cold finger, e.g. during or after cool down. These oscillations would be superimposed on the pressure oscillations of the compressor and could ruin the cooler performance.

de Waele, A. T. A. M.; Liang, W.

2009-02-01

463

Novel materials for laser refrigeration  

NASA Astrophysics Data System (ADS)

The status of optical refrigeration of rare-earth-doped solids is reviewed, and the various factors that limit the performance of current laser-cooling materials are discussed. Efficient optical refrigeration is possible in materials for which h?max < Ep/8, where h&omegamax is the maximum phonon energy of the host material and Ep is the pump energy for the rare-earth dopant. Transition-metal and OH- impurities at levels >100 ppb are believed to be the main reason for the limited laser-cooling performance in current materials. The many components of doped ZBLAN glass pose particular processing challenges. Binary fluoride glasses such as YF3-LiF are considered as alternatives to ZBLAN, and the crystalline system KPb2Cl5 :Dy3+ is identified as a prime candidate for high-efficiency laser cooling.

Hehlen, Markus P.

2009-02-01

464

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

465

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

466

A miniature pulse tube refrigerator for temperatures below 100K  

Microsoft Academic Search

A miniature pulse tube refrigerator reaching temperatures below 100K has been developed. In this paper the test results of the refrigerator are reported. The refrigerator is a orifice pulse tube refrigerator. It is based on a miniature Stirling refrigerator. It consists of a compressor, a cold head and. a reservoir. The features are high operating frequency and compact size. The

Ken-Ichi Kanao; Norihisa Watanabe; Yoshiaki Kanazawa

1994-01-01

467

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

468

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

469

ISS Update: Solar Powered Refrigerator  

NASA Video Gallery

NASA Public Affairs Officer Dan Huot interviews Mike Ewert, Life Support and Thermal Systems Engineer. Ewert co-invented the solar powered refrigerator for stowage of medical samples, preservation of food and cooling of astronauts and thier habitats. Questions? Ask us on Twitter @NASA_Johnson and include the hashtag #askStation. For the latest news about the space station, visit http://www.nasa.gov/station.

Mark Garcia

2012-04-16

470

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

...liquid fill of the storage container does not exceed 80% of the tank's rated volume...4Portable refillable tanks or containers used...Cylinders for Compressed Gasses CGA Pamphlet... 6.1.7The tank assembly shall... 6.4Additional Storage Tank...

2012-07-01

471

Thermoacoustic Refrigerator Design and Performance  

NASA Astrophysics Data System (ADS)

The thermoacoustic theory of N. Rott is applied to a design for a thermoacoustic refrigerator having one moving part. Some general features and practical aspects of the design are discussed. A fully functional refrigerator has been constructed and its measured temperature and efficiency performance is presented. The lowest measured ratio of cold temperature to ambient temperature is 0.66 and the highest measured coefficient of performance relative to Carnot is 12% of Carnot at a temperature ratio of 0.82. The refrigerator is powered by a high-intensity acoustic driver apparatus that is instrumented for accurate measurement of the accoustic power delivered by the driver. The accuracy of the power measurement is (+OR-)3% and the phase between the acoustic pressure and velocity at the driver is measured with an accuracy of (+OR-)1(DEGREES). There are various acoustic losses and heat loading effects that occur in the experiment in addition to the primary measured powers. The magnitude of these additional effects have been either measured or calculated so that a valid comparison between the experiment the Rott theory can be made. The resulting agreement between experiment and theory is fair.

Hofler, Thomas James

472

Simulation of a refrigerant evaporator  

NASA Astrophysics Data System (ADS)

A computer model for the design and optimization of the compressor refrigeration cycle especially with respect to dynamic behavior was developed. A steady state version was also developed. The model describing the refrigerant is divided into the evaporation and superheating regions. A mechanism based on empirics corrects the model for the influence of transportation times in the evaporation region. The mass balance of the refrigerant in the superheat region is regarded as quasi-static, because of the small mass of the vapor. The energy balance accounts for a distributed model and is represented by the steady state solution of the partial differential equation which describes this area for the steady conditions. A correction for the dynamical effects was added to this solution, for all influencing parameters, according to the analytical dynamic solution for the case of the evaporation temperature as input parameter. The expansion device model was worked out for the usual type of device in combination with a dry evaporator, the thermostatic expansion valve. Validation tests are described.

Vandermeer, Jakob Stefanus

473

Compatibility of refrigerants and lubricants with elastomers  

SciTech Connect

Information contained in this reporters designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

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

1992-07-01

474

Screening of pure fluids as alternative refrigerants  

Microsoft Academic Search

Hydrofluorocarbons are now well established as refrigerants because of their zero ozone depletion potential. Since they have a high global warming potential, other alternatives as, e.g. fluorinated ethers or cyclic hydrocarbons are considered as next-generation refrigerants. Screening of alternative refrigerants is difficult because mostly no or only few data are available. To evaluate, e.g. the cycle performance, the thermodynamic properties

B. Saleh; M. Wendland

2006-01-01

475

Vapor-liquid equilibria for hydrogen fluoride + difluoromethane, + 1,1,1,2-tetrafluoroethane, and + 1-chloro-1,2,2,2-tetrafluoromethane at 283.3 and 298.2 K  

SciTech Connect

The production of refrigerants involves the separation of multicomponent mixtures containing hydrogen fluoride, hydrogen chloride, and various chlorinated and fluorinated hydrocarbons. Therefore, it is essential to known the phase behavior of these mixtures. Isothermal vapor-liquid equilibria for hydrogen fluoride (HF) + difluoromethane (HFC-32), HF + 1,1,1,2-tetrafluoroethane (HFC-134a), and HF + 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) were measured by the P-T-x method at 283.3 and 298.2 K. Vapor compositions were calculated from these results. Among these systems, the HF + HFC-134a and HF + HCFC-124 systems exhibit minimum boiling azeotropes at both temperatures.

Lee, J.; Kim, H. [Seoul National Univ. (Korea, Republic of). Dept. of Chemical Engineering; Lim, J.S.; Kim, J.D.; Lee, Y.Y. [KIST, Seoul (Korea, Republic of). CFC Alternatives Technology Center

1996-01-01

476

A global three-dimensional study of the fate of HCFCs and HFC-134a in the troposphere  

NASA Astrophysics Data System (ADS)

We present the first attempt to use a global three-dimensional model of the troposphere to study the degradation chemistry of the alternative chlorofluoro- and fluorohydrocarbons HCFC-22, HCFC-123, HCFC-124, HFC-134a, HCFC-141b, and HCFC-142b and the main removal processes from the troposphere of these halogenated hydrocarbons and their oxidation products. Lifetimes of the parent hydrochlorofluorocarbons (HCFCs) and HFC-134a range from 1.3 to 20 years, with oxidation by