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1

Two-Phase Cooling Method Using R134a Refrigerant to Cool Power Electronic Devices  

SciTech Connect

This paper presents a two-phase cooling method using R134a refrigerant to dissipate the heat energy (loss) generated by power electronics (PE) such as those associated with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles (HEVs). The cooling method involves submerging PE devices in an R134a bath, which limits the junction temperature of PE devices while conserving weight and volume of the heat sink without sacrificing equipment reliability. First, experimental tests that included an extended soak for more than 300 days were performed on a submerged IGBT and gate-controller card to study dielectric characteristics, deterioration effects, and heat flux capability of R134a. Results from these tests illustrate that R134a has high dielectric characteristics, no deterioration on electrical components, and a heat flux of 114 W/cm 2 for the experimental configuration. Second, experimental tests that included simultaneous operation with a mock automotive air-conditioner (A/C) system were performed on the same IGBT and gate controller card. Data extrapolation from these tests determined that a typical automotive A/C system has more than sufficient cooling capacity to cool a typical 30 kW traction inverter. Last, a discussion and simulation of active cooling of the IGBT junction layer with R134a refrigerant is given. This technique will drastically increase the forward current ratings and reliability of the PE device

Lowe, Kirk T [ORNL; Tolbert, Leon M [ORNL; Ayers, Curtis William [ORNL; Ozpineci, Burak [ORNL; Campbell, Jeremy B [ORNL

2007-01-01

2

A solar ejector cooling system using refrigerant R134a in the Athens area  

Microsoft Academic Search

This paper describes the performance of an ejector cooling system driven by solar energy and R134a as working fluid. The system operating in conjunction with intermediate temperature solar collector in Athens, is predicted along the 5 months (May–September). The operation of the system and the related thermodynamics are simulated by suitable computer codes and the required local climatologically data are

G. K. Alexis; E. K. Karayiannis

2005-01-01

3

Experimental investigation on R134a vapour ejector refrigeration system  

Microsoft Academic Search

The experimental investigation of the performance of a vapour ejector refrigeration system is described. The system uses R134a as working fluid and has a rated cooling capacity of 0.5kW. The influence of generator, evaporator and condenser temperatures on the system performance is studied. This kind of system can be operated with low grade thermal energy such as solar energy, waste

A. Selvaraju; A. Mani

2006-01-01

4

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

5

Condensation heat transfer and pressure drop of refrigerant R-134a in a small pipe  

Microsoft Academic Search

The characteristics of condensation heat transfer and pressure drop for refrigerant R-134a flowing in a horizontal small circular pipe that has an inside diameter of 2.0 mm were investigated experimentally in this study. The effects of the heat flux, mass flux, vapor quality and saturation temperature of R-134a on the measured condensation heat transfer and pressure drop were examined in

Yi-Yie Yan; Tsing-Fa Lin

1999-01-01

6

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

7

Evaporation heat transfer and pressure drop of refrigerant R-134a in a small pipe  

Microsoft Academic Search

An experiment was carried out to investigate the characteristics of the evaporation heat transfer and pressure drop for refrigerant R-134a flowing in a horizontal small circular pipe having an inside diameter of 2.0 mm. The data are useful in designing more compact and effective evaporators for various refrigeration and air conditioning systems. The effects of the imposed wall heat flux,

Yi-Yie Yan; Tsing-Fa Lin

1998-01-01

8

Thermal conductivity of refrigerants R123, R134a, and R125 at low temperatures  

Microsoft Academic Search

Using a transient coaxial cylinder technique, thermal conductivities were measured for liquid 1,1,1-trifluoro-2,2-dichloroethane (refrigerant R123), 1,1,1,2-tetrafluoroethane (refrigerant R134a). and pentalluoroethane (refrigerant R 125). The uncertainty of the experimental data is estimated to be within 2–3 %. Thermal conductivities of refrigerants were measured at temperatures ranging from -114 to 20°C under pressures up to IOMPa. The apparatus was calibrated with four

O. B. Tsvetkov; Yu. A. Laptev; A. G. Asambaev

1994-01-01

9

Thermal conductivity of refrigerants R123, R134a, and R125 at low temperatures  

Microsoft Academic Search

Using a transient coaxial cylinder technique, thermal conductivities were measured for liquid 1,1,1-trifluoro-2,2-dichloroethane (refrigerant R123), 1,1,1,2-tetrafluoroethane (refrigerant R134a). and pentalluoroethane (refrigerant R 125). The uncertainty of the experimental data is estimated to be within 2 3 %. Thermal conductivities of refrigerants were measured at temperatures ranging from -114 to 20°C under pressures up to IOMPa. The apparatus was calibrated with

O. B. Tsvetkov; Yu. A. Laptev; A. G. Asambaev

1994-01-01

10

Flow Boiling Heat Transfer of Refrigerants R134a and R245fa in a Horizontal MicroChannel  

Microsoft Academic Search

Micro-channel-based evaporators are a promising option for high heat flux cooling applications. Micro-channels offer several advantages, including a smaller coolant inventory, superior heat transfer performance, compactness, lightness of weigh. Despite being attractive, the governing phenomena in micro-channels, especially during phase change, are less understood. This article reports the experimental flow boiling heat transfer results of refrigerants R134a and R245fa in

R. Ali; B. Palm; M. H. Maqbool

2012-01-01

11

Thermal conductivity of refrigerants R123, R134a, and R125 at low temperatures  

NASA Astrophysics Data System (ADS)

Using a transient coaxial cylinder technique, thermal conductivities were measured for liquid 1,1,1-trifluoro-2,2-dichloroethane (refrigerant R123), 1,1,1,2-tetrafluoroethane (refrigerant R134a). and pentalluoroethane (refrigerant R 125). The uncertainty of the experimental data is estimated to be within 2 3 %. Thermal conductivities of refrigerants were measured at temperatures ranging from -114 to 20°C under pressures up to IOMPa. The apparatus was calibrated with four kinds of liquids and gases. The features of the density dependence of thermal conductivity are indicated. Existing equations for calculating the coefficient are analyzed in cases where development has been sufficient to enable comparisons to be made with experiment. Saturated-liquid thermal conductivities for R134a and R123 are compared with corresponding experimental values.

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

1994-03-01

12

The direct thermal effects of the refrigerant R-134A on atmospheric surface temperature  

NASA Astrophysics Data System (ADS)

The direct thermal effect of refrigerant R-134A (1, 1, 1, 2-tetrafluoroethane) has been evaluated using a one-dimensional radiative-convective model of the atmosphere. The surface temperature increase from a uniform 1 ppbv distribution of R-134A was calculated to be less than 0.04 K, as compared to 0.14 K for 1 ppbv of R-12. Using recent extimates (Anderson L., 1981, Atmospheric Environment15, 1579-1582) of 0.1 ppbv for the worst case ground level concentration of R-134A, our results give a temperature increase from direct thermal heating of 0.004 K, about an order of magnitude less than that from R-12.

Hummel, John R.

13

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

14

Thermal conductivity and thermal diffusivity of the R134a refrigerant in the liquid state  

NASA Astrophysics Data System (ADS)

Thermal conductivity and thermal diffusivity of “ozone-safe” refrigerant R134a in liquid state within the range of temperatures 295.9-354.9 K and pressures from the liquid — vapor equilibrium line up to 4.08 MPa have been studied by high-frequency thermal-wave method. The experimental uncertainties of the temperature, pressure, thermal conductivity and thermal diffusivity measurement errors were estimated to be 0.1 K, 3 kPa, 1.5 and 2.5 %, respectively. Values of thermal conductivity and thermal diffusivity of liquid R134a on saturated line have been calculated. Approximation dependences for thermal conductivity and thermal diffusivity within the whole studied range of temperatures and pressures as well as on the saturated line have been obtained.

Baginsky, A. V.; Shipitsyna, A. S.

2009-06-01

15

Effect of Fin Geometry on Condensation Heat Transfer of Refrigerant R134a on Enhanced Finned Tubes  

NASA Astrophysics Data System (ADS)

This paper presents the experimental results on the outside condensation heat tral1sfer coefficient of horizontal enhanced filmed tubes. Three different fin geometry types of three-dimensional enhanced finned tubes were tested. A low-fin-tube (LFT) 19 fin-per-inch (fpi) was also tested for reference. Experimental refrigerant used was R134a. The heat tral1sfer coefficient test was carried out at a condensing temperature of 40°C, at a cooling water velocity of 1.5 m/s, and the heat flux of 10 to 110 kW/m2K. The outside condensation heat transfer coefficient of all three dimensional enhanced finned tubes were approximately 1.9 times higher than that of LFTl9fpi at high heat flux range. In low heat flux range, the enhanced finned tube of small circumferential segmentation pitches at the fin tip was shown the highest outside heat transfer coefficient for all tubes tested.

Takahashi, Hiroyuki; Saeki, Chikara; Koyama, Shigeru

16

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

17

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

18

Mechanisms of electrohydrodynamic flow boiling heat transfer in coaxial flow channels of dielectric refrigerant R-134a  

Microsoft Academic Search

Experimental and numerical investigations have been conducted to study the mechanisms involved in dielectric refrigerant R-134a electrohydrodynamic (EHD) flow boiling in a concentric horizontal flow channel. Numerical calculations of the electric field distribution in two-phase flow with different gas-liquid distributions and interfacial geometries in a concentric electrode arrangement are conducted by a finite element method. The experiments conducted are performed

J. Cotton; D. Brocilo; M. M. Shoukri; T. Smith-Pollard; J. S. Chang

1998-01-01

19

Experimental Performance of R-1234yf and R-1234ze as Drop-in Replacements for R-134a in Domestic Refrigerators  

SciTech Connect

Concerns about anthropogenic climate change have generated an interest in low global warming potential (GWP) refrigerants and have spawned policies and regulations that encourage the transition to low GWP refrigerants. Recent research has largely focused on hydrofluoroolefins (HFOs), including R-1234yf (GWP = 4) as a replacement for R-134a (GWP = 1430) in automotive air-conditioning applications. While R-1234yf and R-1234ze (GWP = 6) have been investigated theoretically as a replacements for R-134a in domestic refrigeration, there is a lack of experimental evidence. This paper gives experimental performance data for R-1234yf and R-1234ze as drop-in replacements for R134a in two household refrigerators one baseline and one advanced technology. An experiment was conducted to evaluate and compare the performance of R-134a to R-1234yf and R-1234ze, using AHAM standard HRF-1 to evaluate energy consumption. These refrigerants were tested as drop-in replacements, with no performance enhancing modifications to the refrigerators. In Refrigerator 1 and 2, R-1234yf had 2.7% and 1.3% higher energy consumption than R-134a, respectively. This indicates that R-1234yf is a suitable drop-in replacement for R-134a in domestic refrigeration applications. In Refrigerator 1 and 2, R-1234ze had 16% and 5.4% lower energy consumption than R-134a, respectively. In order to replace R-134a with R-1234ze in domestic refrigerators the lower capacity would need to be addressed, thus R-1234ze might not be suitable for drop-in replacement.

Karber, Kyle M [ORNL; Abdelaziz, Omar [ORNL; Vineyard, Edward Allan [ORNL

2012-01-01

20

Experimental studies on heat and mass transfer performance of a coiled tube absorber for R134a-DMAC based absorption cooling system  

NASA Astrophysics Data System (ADS)

Absorber is an important component in vapor absorption refrigeration system and its performance has greater influence in overall efficiency of absorption machines. Falling film heat and mass transfer in an absorber is greatly influenced by fluid properties, geometry of heat exchanger and its operating parameters. This paper presents on the results of experimental studies on the heat and mass transfer characteristics of a coiled tube falling film absorber, using 1,1,1,2-Tetrafluroethane(R-134a) and N-N Dimethyl Acetamide (DMAC) as working fluids. The effects of film Reynolds number, inlet solution temperature and cooling water temperature on absorber heat load, over all heat transfer coefficient and mass of refrigerant absorbed are presented and discussed. Normalized solution and coolant temperature profiles and refrigerant mass absorbed along the height of absorber are also observed from the experimental results. The optimum over all heat transfer coefficient for R-134a DMAC solution found to be 726 W/m2K for a film Reynolds number of 350. The R-134a vapour absorption rate is maximum in the normalized coil height of 0.6 to 1.

Mohideen, S. Tharves; Renganarayanan, S.

2008-04-01

21

Evaporation heat transfer and pressure drop of refrigerant R-134a in a plate heat exchanger  

Microsoft Academic Search

Plate heat exchangers (PHE) have been widely used in food processing, chemical reaction processes, and other industrial applications for many years. Particularly, in the last 20 years plate heat exchangers have been introduced to the refrigeration and air conditioning systems as evaporators or condensers for their high efficiency and compactness. Here, the evaporation heat transfer coefficient and pressure drop for

Y.-Y. Yan; T.-F. Lin

1999-01-01

22

R-134a: The best alternative for chillers  

SciTech Connect

This article proposes R-134a as the best refrigerant alternative for chillers. The topics of the article include automobile industry and refrigerant manufacturers support of R-134a, the pros and cons of R-134a refrigerant, recommended system changes for use of R-134a refrigerant, and retrofitting of R-22 chillers may require replacement of compressors and control devices.

Madan, C. (Continental Products Inc., Indianapolis, IN (United States))

1993-05-01

23

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

24

Thermal conductivity of the new refrigerants R134a, R152a, and R123 measured by the transient hot-wire method  

Microsoft Academic Search

Thermal-conductivity measurements are reported for the new refrigerants R134a, R152a und R123. Transient hot-wire experiments were performed which cover both the liquid and vapor states at temperatures and pressures ranging from?=-20°C to 90°C and fromp=0.1 bar to 60 bar respectively. The results are correlated with density and temperature. In addition temperature dependent correlations are presented for (i) saturated liquid, (ii)

U. Gross; Y. W. Song; E. Hahne

1992-01-01

25

Equation of state and thermmodynamic properties of 1,1,1,2-tetrafluoroethane (refrigerant R134a)  

SciTech Connect

An equation of state and tables of thermodynamic properties of R134a in the saturation state and in the one-phase region are obtained in the temperature interval 320-500 K at pressures ranging from 0.01 to 7.5 MPa.

Vas`kov, E.T. [St. Petersburg State Univ. of Architecture and Civil Engineering (Russian Federation)

1995-08-01

26

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

27

Experimental investigations into the impact of the void fraction on the condensation characteristics of R134a refrigerant in minichannels under conditions of periodic instability  

NASA Astrophysics Data System (ADS)

This paper present the results of experimental investigations of condensation of R134a refrigerant in pipe minichannels with internal diameters 0.64, 0.90, 1.40, 1.44, 1.92 and 3.30 mm subject to periodic pressure instabilities. It was established that as in conventional channels, the displacement velocity of the pressure instabilities distinctly depends on the frequency of their hydrodynamic generation. The void fraction distinctly influences the velocity of the pressure instabilities. The form of this relationship depends on the internal diameter of the minichannels and on the method of calculating the void fraction.

Kuczy?ski, Waldemar; Charun, Henryk

2011-08-01

28

Formation Of CFC Alternative R134a Gas Hydrate  

Microsoft Academic Search

In this study, R134a was selected as an alternative refrigerant for refrigerant gas hydrate as cool storage material. The pressure-tempt:rature phase diagram was determined experimentally. From the phase diagram the critical decomposition temperature, pressure and the heat of formation were obtained. The test of formation-decomposition of gas hydrate were carried out by changing the temperature of the cell using temperature

M. Oowa; M. Nakaiwa; T. Akiya; H. Fukuura; K. Suzuki; M. Ohsuka

1990-01-01

29

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

30

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

31

Effects of flow obstacles on the critical heat flux in a vertical tube cooled with upward flow of R-134a  

Microsoft Academic Search

This paper presents a summary of a 4-year investigation into the effect of flow obstacles on critical heat flux (CHF). The investigation was performed using a vertical 6.92 mm tube, cooled with R-134a. The tests covered a pressure range from 0.96 to 2.39 MPa, a mass flux range from 500 to 3000 kgm?2s?1, and an outlet (critical) quality range from

I. L. Pioro; D. C. Groeneveld; S. S. Doerffer; Y. Guo; S. C. Cheng; A. Vasi?

2002-01-01

32

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

33

R-134a emissions from vehicles.  

PubMed

We report the first study of R-134a (also known as HFC-134a and CF3CFH2) refrigerant leakage from air conditioning (AC) systems of modern vehicles. Twenty-eight light duty vehicles from five manufacturers (Ford, Toyota, Daimler Chrysler, General Motors, and Honda) were tested according to the USEPA (Federal) extended diurnal test procedure using the Sealed Housing for Evaporative Determination (SHED) apparatus. All tests were conducted using stationary vehicles with the motor and air conditioning system turned off. R-134a was measured using gas chromatography (GC) with a flame ionization detector (FID). All vehicles exhibited measurable R-134a leakage over the 2-day diurnal test. Leak rates of R-134a ranged from 0.01 to 0.36 g/day with an average of 0.07+/-0.07 g/day. When combined with leakage associated with vehicle operation, servicing, and disposal we estimate that the lifetime average R-134a emission rate from an AC equipped vehicle is 0.41+/-0.27 g/day (the majority of emissions are associated with vehicle servicing and disposal). Assuming that the average vehicle travels 10 000 miles per year we estimate that the global warming impact of R-134a leakage from an AC equipped vehicle is approximately 4-5% of that of the CO2 emitted by the vehicle. The results are discussed with respect to the contribution of vehicle emissions to global climate change. PMID:11878368

Siegl, W O; Wallington, T J; Guenther, M T; Henney, T; Pawlak, D; Duffy, M

2002-02-15

34

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

35

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

36

Effect of Refrigerant Oil Additive on R134a and R123 Boiling Heat Transfer Performance and Related Issues for GSA.  

National Technical Information Service (NTIS)

The paper investigates the effect that an additive had on the boiling performance of an R134a/polyolester lubricant (POE) mixture and an R123/naphthenic mineral oil mixture on a roughened, horizontal flat surface. Both pool boiling heat transfer data and ...

M. A. Kedzierski

2004-01-01

37

Thermophysical properties of gaseous refrigerants from speed of sound measurements. I. Apparatus, model, and results for 1,1,1,2-tetrafluoroethane R134a  

Microsoft Academic Search

The speed of sound in gaseous 1,1,1,2-tetrafluoroethane (R134a) has been obtained between 233.16 and 340 K from measurements of the frequency of the radial acoustic resonances of a gas-filled spherical cavity. Perfect-gas heat capacities and second and third acoustic virial coefficients have been calculated from the results. The acoustic virial coefficients are used to estimate the density virial coefficients B(T)

A. R. H. Goodwin; M. R. Moldover

1990-01-01

38

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

39

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

40

Experimental Study of the Flow of R-134a Through an Adiabatic Helically Coiled Capillary Tube  

Microsoft Academic Search

An experimental investigation was carried out to evaluate the flow characteristics of refrigerant R-134a through an adiabatic helically coiled capillary tube. The effect of various physical parameters like diameter and length of capillary tube, coil pitch, and inlet subcooling on the mass flow rate of R-134a was investigated. Moreover, the refrigerant mass flow rate through an instrumented capillary tube was

Mohd. Kaleem Khan; Ravi Kumar; Pradeep K. Sahoo

2008-01-01

41

Simulation des propriétés thermodynamiques du fluide R134a  

Microsoft Academic Search

We present in this article, the simples relations of polynomial form to determine the thermodynamic properties of the refrigerant fluid R134a by simulation without having recourse to the abacuses. The equations suggested were determined by numerical methods and are applicable in the interval of saturation temperature of -40°C to 90°C for the saturation state and a real temperature of +

D. Diaf; A. Malek

42

Experimental performance of ozone-safe alternative refrigerants: Experimental performance comparisons of R32, R125, R143a, R218, R134a, R152a, R124, R142b, RC318 and R143 in a refrigeration circuit  

NASA Astrophysics Data System (ADS)

Several compounds proposed as near term or longer range substitutes for the regulated chlorofluorocarbon (CFC) refrigerants were tested in a breadboard vapor-compression circuit, and their performance was evaluated relative to more commonly used refrigerants. The limited physical property information available in the literature for these alternative compounds was used to fit an equation of state so coefficients of performance (COPs) and capacities calculated from refrigerant property subroutines could be compared to those obtained experimentally. Comparisons of measured and modeled performance are given for 11 alternatives and for R22, R12, and R114. Estimates of compressor efficiency with each refrigerant are provided. Several of the alternatives exhibited better performance than the more widely used refrigerants at some or all of the conditions tested. Ozone-safe, alternative refrigerants that performed better than CFC counterparts at selected conditions are R152a, R143a, R134a, R134, and R142b.

Sand, James R.; Vineyard, Edward A.; Nowak, Richard J.

1990-02-01

43

Experimental performance of ozone-safe alternative refrigerants: Experimental performance comparisons of R32, R125, R143a, R218, R134a, R152a, R134, R124, R142b, RC318 and R143 in a refrigeration circuit  

SciTech Connect

Several compounds proposed as near term or longer range substitutes for the regulated chlorofluorocarbon (CFC) refrigerants were tested in a breadboard vapor-compression circuit, and their performance was evaluated relative to more commonly used refrigerants. The limited physical property information available in the literature for these alternative compounds was used to fit an equation of state so coefficients of performance (COPs) and capacities calculated from refrigerant property subroutines could be compared to those obtained experimentally. Comparisons of measured and modeled performance are given for 11 alternatives and for R22, R12, and R114. Estimates of compressor efficiency with each refrigerant are provided. Several of the alternatives exhibited better performance than the more widely used refrigerants at some or all of the conditions tested. Ozone-safe, alternative refrigerants that performed better than CFC counterparts at selected conditions are R152a, R143a, R134a, R134, and R142b. 9 refs., 1 fig., 8 tabs.

Sand, J.R.; Vineyard, E.A. (Oak Ridge National Lab., TN (USA)); Nowak, R.J. (Purdue Univ., Lafayette, IN (USA))

1990-01-01

44

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

45

Experimental studies on heat and mass transfer performance of a coiled tube absorber for R134a-DMAC based absorption cooling system  

Microsoft Academic Search

Absorber is an important component in vapor absorption refrigeration system and its performance has greater influence in overall\\u000a efficiency of absorption machines. Falling film heat and mass transfer in an absorber is greatly influenced by fluid properties,\\u000a geometry of heat exchanger and its operating parameters. This paper presents on the results of experimental studies on the\\u000a heat and mass transfer

S. Tharves Mohideen; S. Renganarayanan

2008-01-01

46

Fundamentals of a floating loop concept based on R134a refrigerant cooling of high heat flux electronics  

Microsoft Academic Search

The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has been developing technologies to address the thermal concerns associated with hybrid electric vehicles (HEVs). This work is part of the ongoing FreedomCAR and Vehicle Technologies program (FCVT), performed for the Department of Energy (DOE). Removal of the heat generated from electrical losses in traction motors

C. W. Ayers; J. S. Hsu; K. T. Lowe

2006-01-01

47

Exergetic analysis of a vapour compression refrigeration system with R134a, R143a, R152a, R404A, R407C, R410A, R502 and R507A  

Microsoft Academic Search

This communication deals with the exergetic analysis of a vapour compression refrigeration system with selected refrigerants.\\u000a The various parameters computed are COP and exergetic efficiency in the system. Effects of degree of condenser temperature,\\u000a evaporator temperature and sub-cooling of condenser outlet, supper-heating of evaporator out let and effectiveness of vapour\\u000a liquid heat exchanger are also computed and discussed. In this

V. Siva Reddy; N. L. Panwar; S. C. Kaushik

48

Effect of Coolant Temperature on the Condensation Heat Transfer in Air-Conditioning and Refrigeration Applications  

Microsoft Academic Search

This article directly investigates the effect of a cooling medium's coolant temperature on the condensation of the refrigerant R-134a. The study presents an experimental investigation into condensation heat transfer, vapor quality, and pressure drop of R-134a flowing through a commercial annular helicoidal pipe under the severe climatic conditions of a Kuwait summer. The quality of the refrigerant is calculated using

M. H. Alhajeri; A. M. Koluib; R. Alajmi; S. P. Kalim

2009-01-01

49

Study of heat pump performance using mixtures of R32/R134A and R32/R125/R134A as drop-in' working fluids for R22 with and without a liquid-suction heat exchanger  

SciTech Connect

A ductless mini-split residential heat pump with a modified indoor coil was utilized to compare the performance of R22 and a mixture of 34% R32/66% R134a by weight. This test was intended to serve as an indicator of 'drop-in' performance so the system was optimized for each refrigerant by varying only the charge mass and expansion valve setting. At the 27.8 C (82 F) cooling test condition the capacity and COP of the mixture were 94% and 90% of the values for R22, respectively. Additional tests were conducted with a liquid-suction intracycle heat exchanger. The modified system was operated with both single-phase and two-phase refrigerant entering the low pressure side of the liquid-suction heat exchanger. The addition of the liquid-suction heat exchanger showed a minimal performance improvement with the performance of the two-phase variation being slightly higher. The best performing liquid-suction heat exchanger variant (two-phase refrigerant on the low pressure side) was also run with a ternary mixture of 30% R32/10% R125/60% R134a, by weight. The results for this mixture were similar to the binary mixture.

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

1993-12-01

50

Comparison of R744 and R134a heat transfer coefficients during flow boiling in a horizontal circular smooth tube  

Microsoft Academic Search

In last and recent years new regulamentations and p rotocols concerning the environmental impact of ref rigerants have led to the research of new environmental friendly refrigerants. In this contest the carbon dioxide (R744) is considered as one of the most promising substitute of the actually most widely used refrigerant in com mercial refrigeration: R134a. However, some technical and thermodynamic

R. Mastrullo; A. W. Mauro; A. Rosato; G. P. Vanoli

51

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

52

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

53

Experimental analysis of a window air conditioner with a R-22 and R32/R125/R134a mixture  

SciTech Connect

Much experimental and theoretical analysis of potential R-22 replacements has been accomplished. However, published information about the experimental analysis of any off-the-shelf air conditioner with a potential R-22 replacement at realistic, operating conditions is still rare. This type of work could be useful because it provides baseline data for comparing the performance of R-22 and its potential replacement at drop-in conditions. In this study, an off-the-shelf window air conditioner was tested at Air Conditioning and Refrigeration Institute (ARI)-rated indoor conditions and at different ambient temperatures, including the ARI-rated outdoor condition, with R-22 and with its potential replacement, a ternary mixture of R-32(30%)/R-125(10%)/R-134a(60%) (the ternary mixture). A test rig was built that provided for baseline operation and for the option of operating the system with a flooded evaporator by means of liquid over-feeding (LOF). The test results indicated the cooling capacity of the ternary mixture was 7.7% less than that of R-22 at 95{degrees}F ambient for baseline operation. The cooling capacity for both refrigerants improved when a flooded evaporator, or LOF, was used. For LOF operation, the cooling capacity of the ternary mixture was only 1.1% less than that of R-22. The ternary mixture had slightly higher compressor discharge pressure, a lower compressor discharge temperature, slightly lower compressor power consumption, and a higher compressor high/low pressure ratio.

Mei, V.C.; Chen, F.C.; Chen, D.T. [Oak Ridge National Lab., TN (United States); HuangFu, E.P. [USDOE, Washington, DC (United States)

1995-07-01

54

Oil cooled, hermetic refrigerant compressor  

DOEpatents

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

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

1985-01-01

55

Oil cooled, hermetic refrigerant compressor  

DOEpatents

A hermetic refrigerant compressor having an electric motor and compressor assembly in a hermetic shell is cooled by oil which is first cooled in an external cooler and is then delivered through the shell to the top of the motor rotor where most of it is flung radially outwardly within the confined space provided by the cap which channels the flow of most of the oil around the top of the stator and then out to a multiplicity of holes to flow down to the sump and provide further cooling of the motor and compressor. Part of the oil descends internally of the motor to the annular chamber to provide oil cooling of the lower part of the motor, with this oil exiting through vent hole also to the sump. Suction gas with entrained oil and liquid refrigerant therein is delivered to an oil separator from which the suction gas passes by a confined path in pipe to the suction plenum and the separated oil drops from the separator to the sump. By providing the oil cooling of the parts, the suction gas is not used for cooling purposes and accordingly increase in superheat is substantially avoided in the passage of the suction gas through the shell to the suction plenum. 3 figs.

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

1985-05-14

56

Condensation pressure drop of R22, R134a and R410A in a single circular microtube  

NASA Astrophysics Data System (ADS)

The condensation pressure drop characteristics for pure refrigerants R22, R134a, and a binary refrigerant mixture R410A without lubricating oil in a single circular microtube were investigated experimentally. The test section consists of 1,220 mm length with horizontal copper tube of 3.38 mm outer diameter and 1.77 mm inner diameter. The experiments were conducted at refrigerant mass flux of 450-1,050 kg/m2s, and saturation temperature of 40°C. The main experimental results showed that the condensation pressure drop of R134a is higher than that of R22 and R410A for the same mass flux. The experimental data were compared against 14 two-phase pressure drop correlations. A new pressure drop model that is based on a superposition model for refrigerants condensing in the single circular tube is presented.

Son, Chang-Hyo; Oh, Hoo-Kyu

2012-08-01

57

Durability of R-134a compressors; The role of the lubricant  

SciTech Connect

With the impending phase-out of CFC-12 (R-12), the most promising alternative as of now is HFC-134a (R-134a). Despite thermodynamic properties as close to R-12 as one can hope for, the problem of substituting R-134a in domestic refrigerator freezers lies in the lack of a compatible lubricant. Polyalkylene glycols (PAGs) have good miscibility with R-134a and were the popular candidates a year or so ago. Today, they seem to have fallen out of favor and appear to have been replaced by polyol esters. True, the publicized problems of PAGs are moisture absorption, partial miscibility with mineral oils used during assembly of compressors, and incompatibility with chlorinated solvents. Other complaints about PAGs concern their somewhat low electrical resistivity as compared to mineral oils, a property important for hermetic applications. However, this too can be handled by good housekeeping involving protection from moisture and the addition of a non-intrusive (200 ppm) stabilizer to the PAG at the point of manufacture. This treatment effectively prevents formation of peroxides and acidic materials (referred to as ionic impurities) in the PAGs, and maintains a reasonably good volume resistivity.

Sanvordenker, K.S. (Tecumseh Products, Ann Arbor, MI (US))

1991-02-01

58

Effect of Oils on Kinematic Viscosity of R134a  

NASA Astrophysics Data System (ADS)

The kinematic viscosity defined as a ratio of viscosity to density is one of the key properties in producing technically important dimensionless numbers such as Prandtl and Reynolds numbers. We measured both viscosity and density of R134a/POE and R134a/PAG mixtures at saturation in the range of relatively low oilconcentrations. The density measurements for oil-concentrations up to 50 mass% were conducted with a densimeter making use of glass buoys within overall uncertainty of ±1.0%, and the viscosity measurements for oil-concentrations up to 16 mass% were carried out with an oscillating-cup viscometer making use of polarizer with overall uncertainty less than ±3.5%. The kinematic viscosities obtained from the experimental viscosity and density data are presented for both R134a/POE and R134a/PAG mixtures in the range of temperatures from 278 K to 288 K for oil-concentrations up to 15 mass%. The oil-concentration dependence of the kinematic viscosity for both mixtures is also reported.

Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

59

Horizontal Nucleate Flow Boiling Heat Transfer Coefficient Measurements and Visual Observations for R12, R134a, and R134a/Ester Lubricant Mixtures.  

National Technical Information Service (NTIS)

The paper presents a calorimetric and visual investigation of horizontal nucleate flow boiling of five different fluids: (1) dichlorodifluoromethane (R12), (2) 1,1,1,2-tetrafluoroethane (R134a), (3) R134a/1.7% proprietary polyol ester lubricant, (4) R134a...

M. A. Kedzierski M. P. Kaul

1993-01-01

60

Study of heat pump performance using mixtures of R32\\/R134A and R32\\/R125\\/R134A as drop-in' working fluids for R22 with and without a liquid-suction heat exchanger  

Microsoft Academic Search

A ductless mini-split residential heat pump with a modified indoor coil was utilized to compare the performance of R22 and a mixture of 34% R32\\/66% R134a by weight. This test was intended to serve as an indicator of 'drop-in' performance so the system was optimized for each refrigerant by varying only the charge mass and expansion valve setting. At the

P. I. Rothfleisch; D. A. Didion

1993-01-01

61

Equations of State for Mixtures of R-32, R-125, R-134a, R-143a, and R-152a  

Microsoft Academic Search

Mixture models explicit in Helmholtz energy have been developed to calculate the thermodynamic properties of refrigerant mixtures containing R-32, R-125, R-134a, R143a, and R-152a. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the compressibility (or real fluid) contribution, and the contribution from mixing. The independent variables are the density, temperature, and composition. The model

Eric W. Lemmon; Richard T Jacobsen

2004-01-01

62

Experimental performance of ozone-safe alternative refrigerants: Experimental performance comparisons of R32, R125, R143a, R218, R134a, R152a, R124, R142b, RC318 and R143 in a refrigeration circuit  

Microsoft Academic Search

Several compounds proposed as near term or longer range substitutes for the regulated chlorofluorocarbon (CFC) refrigerants were tested in a breadboard vapor-compression circuit, and their performance was evaluated relative to more commonly used refrigerants. The limited physical property information available in the literature for these alternative compounds was used to fit an equation of state so coefficients of performance (COPs)

James R. Sand; Edward A. Vineyard; Richard J. Nowak

1990-01-01

63

Solar Cooling by Absorption Refrigerating Machines.  

National Technical Information Service (NTIS)

An absorption refrigerating unit for solar cooling application have been tested at various part load rates. A physical model is developed, on the basis of the thermodynamical cycle and heat transfer characteristics, to evaluate the effects of various inte...

D. Beguin

1983-01-01

64

Elastic Metal Alloy Refrigerants: Thermoelastic Cooling  

SciTech Connect

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

None

2010-10-01

65

Experimental performance of ozone-safe alternative refrigerants: Experimental performance comparisons of R32, R125, R143a, R218, R134a, R152a, R134, R124, R142b, RC318 and R143 in a refrigeration circuit.  

National Technical Information Service (NTIS)

Several compounds proposed as near term or longer range substitutes for the regulated chlorofluorocarbon (CFC) refrigerants were tested in a breadboard vapor-compression circuit, and their performance was evaluated relative to more commonly used refrigera...

J. R. Sand E. A. Vineyard R. J. Nowak

1990-01-01

66

Flow Boiling Heat Transfer and Two-Phase Pressure Drop of R134A in a Microfinned Helically Coiled Tube  

NASA Astrophysics Data System (ADS)

The performance of evaporator is of importance in cryogenic and refrigeration systems. In this paper, evaporative heat transfer and pressure drop characteristics of refrigerant R134a boiling inside a new geometry microfinned helically coiled tube is experimentally studied. Compared with corresponding smooth helically coiled tube, the heat transfer enhancement factors of microfinned helically coiled tube are up to 2.2 with the varieties of mass flux and heat flux. The frictional pressure drop values are obtained by subtracting acceleration pressure drop and gravitational pressure drop from the measured total pressure drop. The frictional pressure drop data can be well correlated using Lockhart-Martinelli method.

Cui, W. Z.; Li, L. J.; Chen, Q. H.; Xin, M. D.

67

Potential Refrigerants for Power Electronics Cooling  

SciTech Connect

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

Starke, M.R.

2005-10-24

68

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

69

Condensation heat transfer and pressure drop characteristics of R-290, R-600a, R-134a and R-22 in horizontal tubes  

NASA Astrophysics Data System (ADS)

This paper presents the experimental results of condensation heat transfer coefficients of hydrocarbon (HC) refrigerants R-290 and R-600a, hydrochlorofluorocarbon (HCFC) refrigerant R-22, and hydrofluorocarbon (HFC) refrigerant R-134a in a horizontal double-pipe heat exchanger having pipe inner diameters of 10.07, 7.73, 6.54, and 5.80 mm. The condensation process experiments were conducted at mass flux of 35.5-210.4 kg/m2 s and condensation temperature of 40°C. The main results were summarized as follows: The average condensation heat transfer coefficients of R-290 and R-600a were higher than those of R-22 and R-134a. The pressure drops of the four refrigerants were in the order of R-600a > R-290 > R-134a > R-22. The pressure drops of R-600a, R-290, R-134a, and R-22 were approximately 6-15, 9.8-12.5, 4.3-6.7, and 2.1-4.6% higher, respectively, in the 10.7 mm diameter tubes compared to the 5.80 mm diameter tubes. Comparing the condensation heat transfer coefficients of our experimental results with those of other correlations, our experimental data in all the test tubes coincided best with that of Haraguchi et al.

Lee, Ho-Saeng; Son, Chang-Hyo

2010-05-01

70

Effect of Lubricant Concentration, Miscibility, and Viscosity on R134a Pool Boiling.  

National Technical Information Service (NTIS)

This paper presents pool boiling heat transfer data for twelve different R134a/lubricant mixtures and pure R134a on a Turbo-BII(trademark)-HP surface. The mixtures were designed to examine the effects of lubricant mass fraction, viscosity, and miscibility...

M. A. Kedzierski

2000-01-01

71

A helium refrigerator with features for supercritical pressure cooling  

NASA Astrophysics Data System (ADS)

The cold end of the helium refrigerator with features for supercritical pressure cooling where it deviates from a conventional refrigerator is described. Two methods of transporting cooling from the load are considered. The first uses a cold circulating pump to circulate helium around the load. The second simply uses the J-T flow from the refrigerator to transport cooling. Measurements have been performed to verify refrigerator capacity. The refrigerator configuration is illustrated, and results of the capacity of the refrigerator and performance data for the ejector and the circulating pump are presented. Operating experience is discussed.

Wu, K. C.; Brown, D. P.; Schlafke, A. P.; Sondericker, J. H.

1983-08-01

72

Design and modelling of hot-wall condensers in domestic refrigerators  

Microsoft Academic Search

This paper presents the experimental and modelling results of hot-wall condensers that are commonly used in domestic vapour compression based refrigerators. Experiments were carried out on a real refrigerator using R134a as the refrigerant to obtain the condenser capacity, pressure loss and degree of sub-cooling at different operating conditions. A simulation model was developed to analyse the heat transfer characteristics

P. K. Bansal; T. C. Chin

2002-01-01

73

Effect of Fin Geometry on Condensation of R134a in a Staggered Bundle of Horizontal Finned Tubes  

NASA Astrophysics Data System (ADS)

Experimental results are presented that show the effect of fin geometry on condensation of refrigerant R134a in a staggered bundle of horizontal fined tubes. Two kinds of conventional low-fin tubes and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 8 to 23 kg/m2s and the condensation temperature difference from 1.5 to 12 K. In most cases, the highest performance was obtained by one of the three-dimensional fin tubes. In the case of high mass velocity and high film Reynolds number, however, the highest performance was obtained by one of the low-fin tubes. The results were compared with previous experimental results for bundles of smooth tubes and low-fin tubes.

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

74

Flow boiling heat transfer of R134a, R236fa and R245fa in a horizontal 1.030 mm circular channel  

Microsoft Academic Search

This research focuses on acquiring accurate flow boiling heat transfer data and flow pattern visualization for three refrigerants, R134a, R236fa and R245fa in a 1.030 mm channel. We investigate trends in the data, and their possible mechanisms, for mass fluxes from 200 to 1600 kg\\/m²s, heat fluxes from 2.3 kW\\/m² to 250 kW\\/m² at T{sub sat} = 31 C and

Chin L. Ong; John R. Thome

2009-01-01

75

Liquid Thermal Conductivity of Ternary Mixtures of Difluoromethane (R32), Pentafluoroethane (R125), and 1,1,1,2-Tetrafluoroethane (R134a) 1  

Microsoft Academic Search

The thermal conductivities of ternary refrigerant mixtures of difluoromethane (R32), pentafluoroethane (R125), and 1,1,1,2-tetrafluoroethane (R134a) in the liquid phase have been measured by the transient hot-wire method with one bare platinum wire. The experiments were performed in the temperature range of 233 to 323 K and in the pressure range of 2 to 20 MPa at various compositions. The measured data are

S. U. Jeong; M. S. Kim; S. T. Ro

2000-01-01

76

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

DOEpatents

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.

Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN

2006-02-07

77

Vapour–liquid equilibrium measurements for binary mixtures of R32, R143a, R134a and R125 with a perfluoropolyether lubricant  

Microsoft Academic Search

In the present work, vapour–liquid equilibria of four binary systems refrigerant–lubricant oil have been investigated, CF3CHF2 (R125), CF3CH2F (R134a), CF3CH3 (R143a) and CH2F2 (R32) as refrigerants and a commercial perfluoropolyether (PFPE), Fluorolink D10H, as lubricant. Vapour–liquid equilibrium data, consisting of isothermal measurement of equilibrium pressure at a fixed composition, have been correlated with an extended Flory–Huggins equation and the corresponding

R Tesser; M Di Serio; R Gargiulo; G Basile; L Bragante; E Santacesaria

2003-01-01

78

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

Microsoft Academic Search

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

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

2006-01-01

79

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

80

Viscosity of R134a, R32, And R125 at Saturation  

Microsoft Academic Search

This paper reports the results of the measurement of the viscosity of R134a close to the saturation line in the vapor phase. The new measurements were carried out in a vibrating-wire viscometer specially constructed for the purpose, and the results have an accuracy of ±2%. In addition, the opportunity is taken to present a reevaluation of earlier measurements along the

C. M. B. P. Oliveira; W. A. Wakeham

1999-01-01

81

Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant.  

National Technical Information Service (NTIS)

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrige...

J. S. Hsu C. W. Ayers C. Coomer L. D. Marlino

2004-01-01

82

Ion signals with R134a and R134 in a parallel plate proportional counter  

NASA Astrophysics Data System (ADS)

The electrical signals from a PPAC (parallel plate avalanche counter) are identical for R134a (1,1,1,2-tetrafluoroethane) and R134 (1,1,2,2-tetrafluoroethane) except for the ion part, which, for R134a, is slower and smaller, but with the same area. The two compounds are identical except for the location of one fluorine atom. With three fluorine atoms on one end, the more common R134a has a large electric dipole moment, about the same as water; while R134 is symmetric, with no dipole moment. The attraction of the polar R134a molecules interferes with the motion of the ions, which results in a longer ion collection time. The counter is two circular plates of 1.0 cm^2 area separated by 0.5 mm operating at 700 torr and 2120 V. The ion signal is constant for a time t0 and then goes linearly to zero at time t1. The values of t0 and t1 are 1.3 ?s and 1.8 ?s for R134a, but only 0.8 ?s and 1.3 ?s for R134. These are not precise times because the signals are very small and the values depend on the location of the primary ion formation (from a ^137Cs ? source). During the constant part of the signal the ions are moving between the plates. The signal goes toward zero as the ions are collected at the cathode. For both gasses the large signal from electrons is fast with a full width at half maximum of only 1.0 ns.

Norbeck, Edwin; Olson, J. E.; Onel, Y.

2006-10-01

83

4. INTERIOR VIEW OF CLUB HOUSE REFRIGERATION UNIT, SHOWING COOLING ...  

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

4. INTERIOR VIEW OF CLUB HOUSE REFRIGERATION UNIT, SHOWING COOLING COILS AND CORK-LINED ROOM. CAMERA IS BETWEEN SEVEN AND EIGHT FEET ABOVE FLOOR LEVEL, FACING SOUTHEAST. - Swan Falls Village, Clubhouse 011, Snake River, Kuna, Ada County, ID

84

110. COMPRESSOR FOR REFRIGERANT COOLING BY WEST WALL OF MECHANICAL ...  

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

110. COMPRESSOR FOR REFRIGERANT COOLING BY WEST WALL OF MECHANICAL EQUIPMENT ROOM (201), LSB (BLDG. 751) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

85

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

86

Cooling-load density optimization for a regenerated air refrigerator  

Microsoft Academic Search

A performance analysis and optimization of a regenerated air refrigeration cycle with variable-temperature heat-reservoirs is carried out by taking the cooling-load density, i.e., the ratio of cooling load to the maximum specific volume in the cycle, as the optimization objective using finite-time thermodynamics (FTT) or entropy-generation minimization (EGM). The model of a regenerated air refrigerator is presented, and analytical relationships

Shengbing Zhou; Lingen Chen; Fengrui Sun; Chih Wu

2004-01-01

87

Flow boiling heat transfer of R134a, R236fa and R245fa in a horizontal 1.030 mm circular channel  

Microsoft Academic Search

This research focuses on acquiring accurate flow boiling heat transfer data and flow pattern visualization for three refrigerants, R134a, R236fa and R245fa in a 1.030mm channel. We investigate trends in the data, and their possible mechanisms, for mass fluxes from 200 to 1600kg\\/m2s, heat fluxes from 2.3kW\\/m2 to 250kW\\/m2 at Tsat=31°C and ?Tsub from 2 to 9K. The local saturated

Chin L. Ong; John R. Thome

2009-01-01

88

Economy of replacing a refrigerant in a cooling system for preparing chilled water  

Microsoft Academic Search

Due to the negative impact of refrigerants containing Cl and Br on the ozone layer, these refrigerants are being replaced with refrigerants containing fluorine. The article describes the replacing of refrigerant R22 in a cooling system for preparing chilled water, used for cooling reactors producing phenol–formaldehyde resins. After analyzing the existing state and the capabilities of the cooling system, the

B. Kulcar; D. Goricanec; J. Krope

2010-01-01

89

Viscosity of R134a, R32, and R125 at saturation  

SciTech Connect

This paper reports the results of the measurement of the viscosity of R134a close to the saturation time in the vapor phase. The new measurements were carried out in a vibrating-wire viscometer specially constructed for the purpose, and the results have an accuracy of {+-}2%. In addition, the opportunity is taken to present a reevaluation of earlier measurements along the saturation line of the viscosity of R32 and R125. Improved equations of state for these fluids are now available and can be employed to generate improved values for the viscosity.

Oliveira, C.M.B.P. [Univ. Aberta, Lisboa (Portugal)]|[Instituto Superior Tecnico, Lisboa (Portugal). Centro de Quimica Estrutural; Wakeham, W.A. [Imperial Coll., London (United Kingdom). Dept. of Chemical Engineering and Chemical Technology

1999-03-01

90

Investigation of potential benefits of compressor cooling  

Microsoft Academic Search

The compressor is certainly the largest power consumer in a vapor compression system. To reduce the power consumption of the compressors two performance improving options are investigated theoretically for refrigerants R22, R134a, R410A and R744 as working fluids. The first option is cooling the motor by external means other than using the suction gas. Analysis results for this option show

Xudong Wang; Yunho Hwang; Reinhard Radermacher

2008-01-01

91

Decomposition of SF6-R134a effluents by RF plasma  

NASA Astrophysics Data System (ADS)

The efficiency of recovery achieved by open or closed loop extraction of RPC exhaust gases is in the range of 90-95% under optimum conditions. For a large detector setup operating on one volume change per day basis, a 5% loss amounts to discharging 50 kg of R134a and 0.5 kg of SF6 into atmosphere every day. The emissions are equivalent to create nearly 50 000 m3 of carbon dioxide daily. The gas emissions need to be completely converted to safer compounds.The gases such as R134a and SF6 are stable compounds. In order to decompose these, the mixture is first activated by adding of 50% oxygen and 2% argon and under typical RF plasma conditions of 13.56 MHz, 1 Torr pressure and 0.2 W/cm2 power density. The chemical reaction takes place on the surface of a silicon electrode. The product of the reaction is mainly SiF4 (gas), which is further hydrolyzed to form HF solution and silicon hydroxide sludge. More than 90% of the effluent gas mixture can be effectively removed by this method.

Joshi, Avinash V.

2012-01-01

92

Equations for the Thermal Conductivity of R-32, R-125, R-134a, and R-143a  

Microsoft Academic Search

At present hydrofluorocarbons (HFCs) such as R32, R-125, R-134a, and R-143a are widely used, and it is required to obtain accurate information of thermophysical properties, especially of the thermal conductivity of HFCs. In this paper new thermal conductivity equations for R-32, R-125, R134a, and R143a are proposed, applicable over a wide range of temperature and pressure including the critical region

J. Yata; Y. Ueda; M. Hori

2005-01-01

93

Cooling SABER with a miniature pulse tube refrigerator  

Microsoft Academic Search

Utah State University\\/Space Dynamics Laboratory, teaming with NASA Langley Research Center, is currently building the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument. Stringent mass and power constraints, together with a greater than two year mission life, led to the selection of a TRW miniature pulse tube refrigerator to cool SABER's infrared detectors to the required temperature of

Scott M. Jensen; J. Clair Batty; William A. Roettker; Matthew J. Felt

1998-01-01

94

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

SciTech Connect

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

None

2010-09-01

95

Cooling SABER with a miniature pulse tube refrigerator  

NASA Astrophysics Data System (ADS)

Utah State University/Space Dynamics Laboratory, teaming with NASA Langley Research Center, is currently building the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument. Stringent mass and power constraints, together with a greater than two year mission life, led to the selection of a TRW miniature pulse tube refrigerator to cool SABER's infrared detectors to the required temperature of 75 K. This paper provides an overview of the SABER thermal management plan and the challenges encountered in matching the refrigerator characteristics with instrument performance requirements under the broadly variant space environments expected for this mission. Innovative technologies were developed to keep heat loads within the limited cooling capacity of the miniature refrigerator, as well as mechanically isolating but thermally connecting the refrigerator cold block to the focal plane assembly (FPA). A passive radiator will maintain the SABER telescope at an average temperature of 230 K while a separate radiator will reject heat from the refrigerator and electronics at approximately 260 K. Significant breadboard tests of various components of the SABER instrument have taken place and the details of one of these will be discussed. The test included attaching a miniature mechanical refrigerator, borrowed from the Air Force, to the SABER FPA. This opportunity gave the SABER team a significant head start in learning about integrating and testing issues related with the TRW miniature pulse tube refrigerator. SABER is scheduled to be launched in January 2000 as the primary instrument of NASA's TIMED (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics) spacecraft. The TIMED program is being managed by the Applied Physics Laboratory at Johns Hopkins University.

Jensen, Scott M.; Batty, J. Clair; Roettker, William A.; Felt, Matthew J.

1998-09-01

96

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

97

Dry climate evaporative cooling with refrigeration backup  

Microsoft Academic Search

Is it possible to provide an industrial owner with an energy efficient evaporative cooling system when his building cannot tolerate the supply air temperature drift if left to the total mercy of the summer ambient wet bulb temperature This paper reports that the ideal humidity guideline should specify a relative humidity range that minimizes deleterious effects on human health and

C. M. Scofield; E. Sterling

1992-01-01

98

A Unique Approach to Power Electronics and Motor Cooling in a Hybrid Electric Vehicle Environment  

Microsoft Academic Search

An innovative system for cooling the power electronics of hybrid electric vehicles is presented. This system uses a typical automotive refrigerant R-134a (1,1,1,2 tetrafluoroethane) as the cooling fluid in a system that can be used as either part of the existing vehicle passenger air conditioning system or separately and independently of the existing air conditioner. Because of the design characteristics,

Curtis William Ayers; J. C. Conklin; J. S. Hsu; K. T. Lowe

2007-01-01

99

Effect of void fraction and friction factor models on the prediction of pressure drop of R134a during downward condensation in a vertical tube  

NASA Astrophysics Data System (ADS)

The theoretical flow models of homogeneous and separated flow are applied to in-tube condensation to predict the pressure drop characteristics of R134a. The homogeneous flow model is modified by ten different dynamic viscosity correlations and various alternative correlations of total, frictional and momentum pressure drops to take account of the partial condensation inside the tube. Numerical analyses were performed to determine the average and local homogeneous wall shear stresses and friction factors by means of a CFD program. The equivalent Reynolds number model is modified by six different two-phase friction factors to determine the total condensation pressure drop in the separated flow model. The refrigerant side total pressure drops, frictional pressure drops, friction factors and wall shear stresses are determined within a ±30% error band. The importance of using the alternative total, momentum and frictional pressure drop correlations for the homogeneous flow model is also shown.

Dalkilic, A. S.; Kürekci, N. A.; Wongwises, S.

2012-01-01

100

An overview and comparison of various refrigeration methods for microelectronics cooling  

Microsoft Academic Search

Small-scale refrigerators, termed mesoscale refrigerators, are possible cooling solutions for high-power microelectronics. The performance of mesoscale refrigerators has not yet been experimentally demonstrated, although a recent theoretical model indicated that at temperatures near room temperature and above, a vapor compression refrigerator may compete successfully with a thermoelectric cooler having extremely high efficiency [1]. The present study proposes an overview and

Victor Chiriac; Florea Chiriac

2008-01-01

101

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

102

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

103

Development of atmospheric characteristics of chlorine-free alternative fluorocarbons. Report on R-134a and E-143a  

SciTech Connect

Rate constants have been measured for the gas phase reaction of OH radicals with 1,1,1,2-tetrafluoroethane R-134a (CH{sub 2}F-CF{sub 3}) and methyl trifluoromethyl ether E-143a (CH{sub 3}-O-CF{sub 3}) over the temperature range 298--460 K. Arrhenius expressions were derived for atmospheric modeling. The infrared absorption cross-sections for R-134a and E-143a have been measured in the region from 400 to 1600 cm{sup {minus}1} and the integrated band strengths have been calculated. The atmospheric lifetimes R-134a and E-143a have been estimated to be 11.6 years and 4.1 years respectively. Global warming potentials have been estimated over time horizons of 20, 50, 100, 200, and 500 years.

Orkin, V.L.; Khamaganov, V.G.; Guschin, A.G.; Kasimovskaya, E.E.; Larin, I.K. [Institut Energeticheskiskh Problem Khimicheskoi Fiziki, Moscow (Russian Federation)

1993-04-01

104

Measurements of the Viscosity for Mixtures of R134a and Polyolester Oil at Low Oil-concentrations  

NASA Astrophysics Data System (ADS)

The paper presents new measurements on the viscosity for the mixtures of R134a and polyolester oil at low oil-concentrations. The measurements were conducted with a newly developed oscillating cup viscometer making use of polarizer at oil-concentrations between 0 and 16 mass% and temperatures from 278.15 K to 288.15 K. The uncertainty in viscosity was estimated to be less than ±4.3%. It was found that even a small amount of the oil into R134a had a significant effect on the viscosity. It increased exponentially with oil-concentration. Mixing the oil into R134a up to an oil-concentration of 16 mass% tripled the viscosity. A correlation equation as a function of temperature and oil mass fraction was formulated to interpolate the experimental viscosity data.

Sato, Tomoaki; Odaira, Akihiro; Takaishi, Yoshinori; Oguchi, Kosei

105

Heat and mass transfer characteristics of absorption of R134a into DMAC in a horizontal tube absorber  

NASA Astrophysics Data System (ADS)

In this paper the heat and mass transfer characteristics of a horizontal tube absorber for the mixture R134a/DMAC in terms of experimentally gained heat and mass transfer coefficients are presented. The heat transfer coefficient is mainly dependent on the solution’s mass flow rate. The mass transfer coefficient is strongly related to the subcooling of the solution. The data are compared to experimental absorption characteristics of water into aqueous lithium bromide in an absorption chiller. The mass transfer coefficients are of similar size whereas the heat transfer coefficients are about one order of magnitude smaller for R134a-DMAC.

Harikrishnan, L.; Maiya, M. P.; Tiwari, S.; Wohlfeil, A.; Ziegler, F.

2009-10-01

106

Heating surface material’s effect on subcooled flow boiling heat transfer of R134a  

SciTech Connect

In this study, subcooled flow boiling of R134a on copper (Cu) and stainless steel (SS) heating surfaces was experimentally investigated from both macroscopic and microscopic points of view. By utilizing a high-speed digital camera, bubble growth rate, bubble departure size, and nucleation site density, were able to be observed and analyzed from the microscopic point of view. Macroscopic characteristics of the subcooled flow boiling, such as heat transfer coefficient, were able to be measured as well. Experimental results showed that there are no obvious difference between the copper and the stainless surface with respect to bubble dynamics, such as contact angle, growth rate and departure size. On the contrary, the results clearly showed a trend that the copper surface had a better performance than the stainless steel surface in terms of heat transfer coefficient. It was also observed that wall heat fluxes on both surfaces were found highly correlated with nucleation site density, as bubble hydrodynamics are similar on these two surfaces. The difference between these two surfaces was concluded as results of different surface thermal conductivities.

Ling Zou; Barclay G. Jones

2012-11-01

107

Refrigerator-cooled cryostats for research on inertial confinement fusion  

SciTech Connect

In order to utilize the increased density of liquified or solidified DT fuel, one must provide means for cooling fusion targets to the range 15 K to 25 K. The heat loads at these low temperatures can be kept modest by providing adequate thermal shielding maintained near 75 K. Modern closed-cycle-helium refrigerators, operating on the Gifford-McMahon cycle, provide for both thermal loads reliably and inexpensively, thanks to the increasing implementation of the commercial cryopump. By adding a large sealed can containing helium exchange gas to the second state of the refrigerator, we create a nearly ideal environment for cryogenic fusion targets. We discuss the design and operation of two separate apparatus. One has been used almost continuously over the past two years for various inertial confinement fusion studies. 5 refs., 3 figs.

Hoffer, J.K.; Candler, R.J.

1988-01-01

108

Solar hybrid cooling system for high-tech offices in subtropical climate – Radiant cooling by absorption refrigeration and desiccant dehumidification  

Microsoft Academic Search

A solar hybrid cooling design is proposed for high cooling load demand in hot and humid climate. For the typical building cooling load, the system can handle the zone cooling load (mainly sensible) by radiant cooling with the chilled water from absorption refrigeration, while the ventilation load (largely latent) by desiccant dehumidification. This hybrid system utilizes solar energy for driving

K. F. Fong; T. T. Chow; C. K. Lee; Z. Lin; L. S. Chan

2011-01-01

109

Effect of CuO Nanolubricant on R134a Pool Boiling Heat Transfer with Extensive Measurement and Analysis Details.  

National Technical Information Service (NTIS)

This paper quantifies the influence of CuO nanoparticles on the boiling performance of R134a/polyolester mixtures on a roughened, horizontal, flat surface. Nanofluids are liquids that contain dispersed nano-size particles. A lubricant based nanofluid (nan...

M. Gong M. A. Kedzierski

2007-01-01

110

Electron swarm coefficients in 1,1,1,2 tetrafluoroethane (R134a) and its mixtures with Ar  

NASA Astrophysics Data System (ADS)

Using a pulsed Townsend technique, we have measured the drift velocity, the longitudinal diffusion coefficient and the effective ionisation coefficient of electrons in R134a and R134a-Ar over a wide range of the density-reduced electric field intensity, E/N. Regarding the measurement of the electron drift velocities and of the effective ionization coefficients, we have covered a wider range than that hitherto achieved for pure R134a. Both the electron drift velocity and the effective ionisation coefficient have been found in very good agreement with those published in the literature, covering a shorter range of E/N. On the other hand, the swarm coefficients on R134a-Ar are, to the best of our knowledge, the first to be published. It is hoped that these data will be of interest for the test/derivation of electron collision cross sections for this important hydrofluorocarbon gas, which is nowadays of great use in gaseous detectors.

de Urquijo, J.; Juárez, A. M.; Basurto, E.; Hernández-Ávila, J. L.

2009-02-01

111

Effect of CuO Nanparticle Concentration on R134a/Lubricant Pool Boiling Heat Transfer with Extensive Analysis.  

National Technical Information Service (NTIS)

This paper quantifies the influence of copper (II) oxide (CuO) nanoparticle concentration on the boiling performance of R134a/polyolester mixtures on a roughened, horizontal flat surface. Nanofluids are liquids that contain dispersed nano-size particles. ...

M. A. Kedzierski

2007-01-01

112

Experimental investigation on condensation heat transfer and pressure drop of R134a in a plate heat exchanger  

Microsoft Academic Search

Condensation heat transfer of R134a in a vertical plate heat exchanger was investigated experimentally. The local heat transfer coefficients are determined by means of the measured local wall temperatures. A differential energy balance model is developed for data evaluation. It is found that the correlation proposed by Shah using Psi and Z factors is suitable for condensation in plate heat

Z.-Y. Shi; J.-P. Chen; V. Grabenstein; S. Kabelac

2010-01-01

113

Two-phase flow in high-heat-flux micro-channel heat sink for refrigeration cooling applications: Part II—heat transfer characteristics  

Microsoft Academic Search

This paper is the second of a two-part study concerning two-phase flow and heat transfer characteristics of R134a in a micro-channel heat sink incorporated as an evaporator in a refrigeration cycle. Boiling heat transfer coefficients were measured by controlling heat flux (q?=15.9?93.8W\\/cm2) and vapor quality (xe=0.26?0.87) over a broad range of mass velocity. While prior studies point to either nucleate

Jaeseon Lee; Issam Mudawar

2005-01-01

114

Flow boiling heat transfer study of R-134a/R-290/R-600a mixture in 9.52 and 12.7 mm smooth horizontal tubes: Experimental investigation  

SciTech Connect

A detailed experimental investigation is carried out to study the flow boiling heat transfer behavior of R-134a/R-290/R-600a (91%/4.068%/4.932% by mass) refrigerant mixture in smooth horizontal tubes of diameter 9.52 and 12.7 mm. The heat transfer coefficients of the mixture are experimentally measured under varied heat flux conditions for stratified flow patterns using a coaxial counter-current heat exchanger test section. The tests are conducted for refrigerant inlet temperatures between -9 and 5 C and mass flow rates ranging from 3 to 5 g s{sup -1}. Kattan-Thome-Favrat maps are used to confirm the flow patterns for the tested conditions. The magnitude of the heat transfer coefficient with respect to flow patterns and different mechanisms of boiling are discussed. The heat transfer coefficient of the refrigerant mixture is also compared with that of R-134a for selected working conditions. The significance of nucleate boiling in the overall heat transfer process under these testing conditions is highlighted. (author)

Raja, B.; Mohan Lal, D.; Saravanan, R. [R and AC Division, Dept. of Mechanical Engg., College of Engineering, Guindy, Anna University, 1, Sardar Patel Road, Chennai 600 025 (India)

2009-03-15

115

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

116

Experimental study of R134A condensation heat transfer inside the horizontal micro-fin tubes  

NASA Astrophysics Data System (ADS)

The Investigation of the two-phase flow patterns and their transitions during the condensation has gained increasing interest and importance from the well-known phenomenon that the heat transfer characteristics are strongly dependent on the flow patterns. Therefore, it is very important to study on which heat transfer enhancement approach is suitable for an individual flow pattern inside a condenser, so that an accurate heat transfer mechanism can be understood that is consistent with the flow patterns. The condensation heat transfer for R134a in the two kinds of in-tube three-dimensional (3-D) micro-fin tubes with different geometries is experimentally investigated. Based on the flow pattern observations, the flow patterns in the Soliman flow regime map are divided into two-flow regimes; one with the vapor-shear-dominant annular regime and the other with the gravitational-force-dominant stratified-wavy regime. The flow regime transition criterion between the annular regime and the stratified-wavy regime is at Fr equal to 2. In the annular regime, the heat transfer coefficients h of the two kinds of in-tube 3-D micro-fin tubes decreases as the vapor quality x decreases. The regressed condensation heat transfer correlation from the experimental data of the annular flow region is obtained. The dispersibility of the experimental data is inside the limits of ±25%. In the stratified-wavy regime, the average heat transfer coefficient h of the two kinds of in-tube 3-D micro-fin tubes increases as the mass flux increases and the number of micro fins in the 3-D micro-fin tube is not the controlling factor for the performance of a condensation heat transfer. The regressed condensation heat transfer correlation of the stratified-wavy flow regime is experimentally obtained. The dispersibility of the experimental data is inside the limits of ±22%. Combined with the criteria of flow pattern transitions, the correlations can be used for the design of a condenser with 3-D micro-fin tubes.

Chen, Q.; Amano, R. S.; Xin, M. D.

2005-07-01

117

Refrigeration assisted spot cooling of a high heat density data center  

Microsoft Academic Search

Analytical modeling of two kinds of direct expansion refrigeration cooling evaporator and a secondary liquid cooling fan coil heat exchanger is incorporated with computational fluid dynamics (CFD) model to analyze a high heat density electronic and computer data center installed on a raised floor. Both models incorporate an accurate tube-by-tube thermal hydraulic modeling of the heat exchanger. The refrigeration coil

Ali Heydari; P. Sabounchi

2004-01-01

118

Vapor-liquid equilibria for an R134a/lubricant mixture: Measurements and equation-of-state modeling  

SciTech Connect

The authors measured bubble point pressures and coexisting liquid densities for two mixtures of R-134a and a polyolester (POE) lubricant. The mass fraction of the lubricant was approximately 9% and 12%, and the temperature ranged from 280 K to 355 K. The authors used the Elliott, Suresh, and Donohue (ESD) equation of state to model the bubble point pressure data. The bubble point pressures were represented with an average absolute deviation of 2.5%. A binary interaction parameter reduced the deviation to 1.4%. The authors also applied the ESD model to other R-134a/POE lubricant data in the literature. As the concentration of the lubricant increased, the performance of the model deteriorated markedly. However, the use of a single binary interaction parameter reduced the deviations significantly.

Huber, M.L.; Holcomb, C.D.; Outcalt, S.L.; Elliott, J.R.

2000-07-01

119

Experimental investigation on condensation heat transfer and pressure drop of R134a in a plate heat exchanger  

NASA Astrophysics Data System (ADS)

Condensation heat transfer of R134a in a vertical plate heat exchanger was investigated experimentally. The local heat transfer coefficients are determined by means of the measured local wall temperatures. A differential energy balance model is developed for data evaluation. It is found that the correlation proposed by Shah using ? and Z factors is suitable for condensation in plate heat exchangers and is adopted to fit the measured data.

Shi, Z.-Y.; Chen, J.-P.; Grabenstein, V.; Kabelac, S.

2010-11-01

120

Experimental Performance of R-134a-Filled and Water-Filled Loop Heat Pipe Heat Exchangers  

Microsoft Academic Search

Experimental investigations were conducted to determine the thermal performances of an R-134a-filled thermosyphon heat pipe heat exchanger (THPHE) and a water-filled loop heat pipe heat exchanger (LHPHE) for hot and cold energy recovery for air conditioning purposes. For such applications, the heat pipe heat exchangers are operated at low temperatures. Both exchangers were operated in the countercurrent flow mode. This

K. S. Ong

2010-01-01

121

Flow boiling heat transfer of R134a and R245fa in a 2.3 mm tube  

Microsoft Academic Search

This paper presents new experimental flow boiling heat transfer results in micro-scale tubes. The experimental data were obtained in a horizontal 2.3mm I.D. stainless steel tube with heating length of 464mm, R134a and R245fa as working fluids, mass velocities ranging from 50 to 700kgm?2s?1, heat flux from 5 to 55kWm?2, exit saturation temperatures of 22, 31 and 41°C, and vapor

Cristiano Bigonha Tibiriçá; Gherhardt Ribatski

2010-01-01

122

Experimental investigation on condensation heat transfer and pressure drop of R134a in a plate heat exchanger  

Microsoft Academic Search

Condensation heat transfer of R134a in a vertical plate heat exchanger was investigated experimentally. The local heat transfer\\u000a coefficients are determined by means of the measured local wall temperatures. A differential energy balance model is developed\\u000a for data evaluation. It is found that the correlation proposed by Shah using ? and Z factors is suitable for condensation in plate heat

Z.-Y. Shi; J.-P. Chen; V. Grabenstein; S. Kabelac

2010-01-01

123

Liquid Thermal Conductivity of Binary Mixtures of Pentafluoroethane (R125) and 1,1,1,2-Tetrafluoroethane (R134a)  

Microsoft Academic Search

Thermal conductivities of zeotropic mixtures of R125 (CF3CHF2) and R134a (CF3CH2F) in the liquid phase are reported. Thermal conductivities have been measured by a transient hot-wire method with one bare platinum wire. Measurements have been carried out in the temperature range of 233 to 323 K and in the pressure range of 2 to 20 MPa. The dependence of thermal

S. U. Jeong; M. S. Kim; S. T. Ro

1999-01-01

124

Critical heat flux performance for flow boiling of R-134a in vertical uniformly heated smooth tube and rifled tubes  

Microsoft Academic Search

In the present paper, critical heat flux (CHF) experiments for flow boiling of R-134a were performed to investigate the CHF characteristics of four-head and six-head rifled tubes in comparison with a smooth tube. Both of rifled tubes having different head geometry have the maximum inner diameter of 17.04mm while the smooth tube has the average inner diameter of 17.04mm. The

Chang Ho Kim; In Cheol Bang; Soon Heung Chang

2005-01-01

125

Experimental study of post-dryout with R-134a upward flow in smooth tube and rifled tubes  

Microsoft Academic Search

A study of post-dryout heat transfer was performed with a directed heated smooth tube and rifled tubes using vertical R-134a up-flow to investigate the heat transfer characteristics in the post-dryout region. Three types of rifled tube having different rib height and width were used to examine the effects of rib geometry and compare with the smooth tube, using a mass

Song Kyu Lee; Soon Heung Chang

2008-01-01

126

Two-phase flow in high-heat-flux micro-channel heat sink for refrigeration cooling applications: Part I––pressure drop characteristics  

Microsoft Academic Search

Two-phase pressure drop was measured across a micro-channel heat sink that served as an evaporator in a refrigeration cycle. The micro-channels were formed by machining 231?m wide×713?m deep grooves into the surface of a copper block. Experiments were performed with refrigerant R134a that spanned the following conditions: inlet pressure of Pin=1.44–6.60bar, mass velocity of G=127–654kg\\/m2s, inlet quality of xe,in=0.001–0.25, outlet

Jaeseon Lee; Issam Mudawar

2005-01-01

127

Flow boiling heat transfer of R134a, R236fa and R245fa in a horizontal 1.030 mm circular channel  

SciTech Connect

This research focuses on acquiring accurate flow boiling heat transfer data and flow pattern visualization for three refrigerants, R134a, R236fa and R245fa in a 1.030 mm channel. We investigate trends in the data, and their possible mechanisms, for mass fluxes from 200 to 1600 kg/m{sup 2}s, heat fluxes from 2.3 kW/m{sup 2} to 250 kW/m{sup 2} at T{sub sat} = 31 C and {delta}T{sub sub} from 2 to 9 K. The local saturated flow boiling heat transfer coefficients display a heat flux and a mass flux dependency but no residual subcooling influence. The changes in heat transfer trends correspond well with flow regime transitions. These were segregated into the isolated bubble (IB) regime, the coalescing bubble (CB) regime, and the annular (A) regime for the three fluids. The importance of nucleate boiling and forced convection in these small channels is still relatively unclear and requires further research. (author)

Ong, Chin L.; Thome, John R. [Laboratory of Heat and Mass Transfer (LTCM), Ecole Polytechnique Federale de Lausanne (EPFL), ME G0 520 ME Station 9, Lausanne CH 1015 (Switzerland)

2009-04-15

128

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

129

Mass recovery adsorption refrigeration cycle—improving cooling capacity  

Microsoft Academic Search

The study investigates the performance of two-bed, silica gel-water adsorption refrigeration cycle with mass recovery process. The cycle with mass recovery can be driven by the relatively low temperature heat source. In an adsorption refrigeration cycle, the pressures in adsorber and desorber are different. The chiller with mass recovery process utilizes the pressure difference to enhance the refrigerant mass circulation.

Akira Akahira; K. C. A. Alam; Yoshinori Hamamoto; Atsushi Akisawa; Takao Kashiwagi

2004-01-01

130

An investigation of a model of the flow pattern transition mechanism in relation to the identification of annular flow of R134a in a vertical tube using various void fraction models and flow regime maps  

SciTech Connect

In the present study, new experimental data are presented for literature on the prediction of film thickness and identification of flow regime during the co-current downward condensation in a vertical smooth copper tube having an inner diameter of 8.1 mm and a length of 500 mm. R134a and water are used as working fluids in the tube side and annular side of a double tube heat exchanger, respectively. Condensation experiments are done at mass fluxes of 300 and 515 kg m{sup -2} s{sup -1}. The condensing temperatures are between 40 and 50 C; heat fluxes are between 12.65 and 66.61 kW m{sup -2}. The average experimental heat transfer coefficient of the refrigerant HFC-134a is calculated by applying an energy balance based on the energy transferred from the test section. A mathematical model by Barnea et al. based on the momentum balance of liquid and vapor phases is used to determine the condensation film thickness of R134a. The comparative film thickness values are determined indirectly using relevant measured data together with various void fraction models and correlations reported in the open literature. The effects of heat flux, mass flux, and condensation temperature on the film thickness and condensation heat transfer coefficient are also discussed for the laminar and turbulent flow conditions. There is a good agreement between the film thickness results obtained from the theoretical model and those obtained from six of 35 void fraction models in the high mass flux region of R134a. In spite of their different valid conditions, six well-known flow regime maps from the literature are found to be predictive for the annular flow conditions in the test tube in spite of their different operating conditions. (author)

Dalkilic, A.S. [Heat and Thermodynamics Division, Department of Mechanical Engineering, Yildiz Technical University, Yildiz, Besiktas, Istanbul 34349 (Turkey); Wongwises, S. [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

2010-09-15

131

Evaluation of the protective properties of organic coatings on copper pipes for refrigerator cooling circuit  

Microsoft Academic Search

Copper pipes which are widely used in the refrigerator industry can sometimes work in high humidity atmospheres and in aggressive conditions which can produce dangerous corrosion phenomena of the pipes. Moreover, the design of the refrigerator cooling circuit can introduce some other corrosion problems because copper pipes are frequently in electrical contact with aluminium pipes causing serious galvanic attack on

Lorenzo Fedrizzi; Flavio Deflorian; PierLuigi Bonora

1999-01-01

132

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

133

Optical refrigeration progress: cooling below NIST cryogenic temperature of 123K  

NASA Astrophysics Data System (ADS)

We have achieved cryogenic optical refrigeration with a record low temperature in optical refrigeration by cooling 5% wt.Yb:YLF crystal to 119K +/-1K (~-154 C) at 1=1020 nm corresponding to its E4-E5 Stark manifold resonance with an estimated cooling power of 18 mW. This demonstration confirms the predicted minimum achievable temperature (MAT). Further cooling is achievable as shown by measurements of a doping study where a 10% wt. Yb:YLF crystal with reduced parasitic heating has predicted cooling below 100K (~-173K).

Melgaard, Seth D.; Seletskiy, Denis V.; Di Lieto, Alberto; Tonelli, Mauro; Sheik-Bahae, Mansoor

2013-03-01

134

Concentration Dependence of Pool Nucleate Boiling Heat Transfer Coefficients for R134a and Polyolester Oil System  

NASA Astrophysics Data System (ADS)

This paper presents experimental results of the concentration dependence of heat transfer coefficients for mixtures of R134a and polyolester (POE) oil under the conditions of pool nuc1eateboiling. The experiments are conducted by means of ah horizontal platinum wire at saturation tel11peraturesof 9, 19, and 29°C and at oil concentrations from 0 to 8 mass%. The present results show that the boiling heat transfer coefficient for the system concerned decreases with increasing oil concentration as a whole but increases slightly at a low oil concentration of about 4 mass%. A correlation equation is also given as a function of heat flux, temperature and oil concentration to reproduce the experimental boiling heat transfer coefficient within an uncertainly of about±15%.

Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

135

Liquid thermal conductivity of binary mixtures of pentafluoroethane (R125) and 1,1,1,2-tetrafluoroethane (R134a)  

SciTech Connect

Thermal conductivities of zeotropic mixtures of R125 (CF{sub 3}CHF{sub 2}) and R134a (CF{sub 3}CH{sub 2}F) in the liquid phase are reported. Thermal conductivities have been measured by a transient hot-wire method with one bare platinum wire. Measurements have been carried out in the temperature range of 233 to 323 K and in the pressure range of 2 to 20 MPa. The dependence of thermal conductivity on temperature, pressure, and composition of the binary mixture is presented. Measured thermal conductivity data are correlated as a function of temperature, pressure, and overall composition of the mixture. The uncertainty of the measurements was estimated to be better than 2%.

Jeong, S.U.; Kim, M.S.; Ro, S.T. [Seoul National Univ. (Korea, Republic of). Dept. of Mechanical Engineering

1999-01-01

136

IMPACTS OF REFRIGERANTLINE LENGTH ON SYSTEM EFFICIENCY IN RESIDENTIAL HEATING AND COOLING SYSTEMS USING REFRIGERANT DISTRIBUTION.  

SciTech Connect

The effects on system efficiency of excess refrigerant line length are calculated for an idealized residential heating and cooling system. By excess line length is meant refrigerant tubing in excess of the 25 R provided for in standard equipment efficiency test methods. The purpose of the calculation is to provide input for a proposed method for evaluating refrigerant distribution system efficiency. A refrigerant distribution system uses refrigerant (instead of ducts or pipes) to carry heat and/or cooling effect from the equipment to the spaces in the building in which it is used. Such systems would include so-called mini-splits as well as more conventional split systems that for one reason or another have the indoor and outdoor coils separated by more than 25 ft. This report performs first-order calculations of the effects on system efficiency, in both the heating and cooling modes, of pressure drops within the refrigerant lines and of heat transfer between the refrigerant lines and the space surrounding them.

ANDREWS, J.W.

2001-04-01

137

Characterization of refrigerant - 12 gas hydrate formation for heat pump cool storage applications  

Microsoft Academic Search

A latent cool storage system for load management applications is currently under development at Oak Ridge National Laboratory. This system utilizes a refrigerant gas hydrate as the storage medium and incorporates storage directly into the heat pump cycle. This paper reviews the chemistry of gas hydrates, describes the conceptual heat pump\\/cool storage system, and presents the results from experiments performed

1984-01-01

138

Absorption refrigeration method with alternative water-ammonia solution circulation system for microelectronics cooling  

Microsoft Academic Search

The study develops an analytical model of an optimized small scale absorption ammonia\\/water refrigeration system, designed to fit smaller scale power electronics, using a pump to circulate the binary ammonia-water solution cooling agent in the proposed miniaturized system. This continues the authors' previous study of a refrigeration absorption system, by replacing the thermo-siphon and gravitational based circulation of the compensatory

Victor Chiriac; Florea Chiriac

2010-01-01

139

The alternative refrigerant dilemma for refrigerator-freezers: Truth or consequences  

SciTech Connect

In an effort to select a refrigerant that has minimal impact on energy consumption and the environment, a screening analysis of potential refrigerants was performed that resulted in the selection of six candidates. The screening results show that R-134a, R-134, R-152a, R-134a/R-152a, R-22/R-152a/R-124, and R-134a/R-152a/R-124 are the most promising refrigerants based on the following criteria: ozone depletion potential, greenhouse warming potential, coefficient of performance, and safety. Energy consumption tests were performed for the three pure refrigerants in accordance with the Association of Home Appliance Manufacturers standard for household refrigerators and household freezers. The results indicate an increased energy consumption of 6.8%, 7.3%, and 7.3%, respectively for R-134, R-152a, and R-134a in the most efficient oil. However, when the effects of compressor efficiency are taken into account, the normalized energy consumption results in an increase of only 2.7% for R-152a and 5.5% for both R-134a and R-134. 14 refs., 5 tabs.

Vineyard, E.A.

1991-01-01

140

Visualization of Sub-Cooled Flow Film Boiling in Horizontal Channel on Flat Heat Exchangers  

SciTech Connect

The observation of sub-cooled flow film boiling was performed on a single-side-heated flat heat exchanger by using refrigerant R134a as the testing fluid. A stable vapor film was observed with the co-existence of sub-cooled bulk liquid. Vapor bubbles might release from the film, with the number and frequency changing under different conditions. The purpose of this paper is to describe these observations, and to provide a quantitative analysis of the phenomena. Results are compared with Berenson's model on horizontal heating surface, with discussion and suggestion made. (authors)

Wen Wu; Peipei Chen; Jones, Barclay G.; Newell, Ty A. [University of Illinois at Urbana-Champaign, Urbana, IL, 61801 (United States)

2006-07-01

141

Study of mixed refrigerant undergoing pulsating flow in micro coolers with pre-cooling  

NASA Astrophysics Data System (ADS)

Micro cryogenic coolers can provide low temperatures with a smaller volumetric footprint and smaller power draw than their conventional-scale counterparts. However, they can exhibit lower-than-desired cooling power. We measure the specific cooling power of a refrigerant expanding from a high pressure of 0.6 MPa to a low pressure of 0.1 MPa, while undergoing pulsating flow in a micro cryogenic cooler with pre-cooling. We further observe that the pulses in the flow-rate occur due to a volume of liquid forming in the high-pressure coupling mini-channel. The composition of the flowing refrigerant is analyzed with gas chromatography and thermal conductivity detection (GC/TCD), showing that there is no overall composition change in the refrigerant after it enters the pre-cooling lines. A model of the cooling power under such a pulsating flow regime is developed with good agreement to measured values. An improved refrigerant mixture is designed with this model, and subsequently tested, showing increased specific cooling power.

Lewis, Ryan; Wang, Yunda; Schneider, Hayley; Lee, Y. C.; Radebaugh, Ray

2013-10-01

142

Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane + 1,1,1,2-tetrafluoroethane (R125/R134a)  

SciTech Connect

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1,2-tetrafluoroethane (R134a) was measured along four isotherms between 283 K and 313 K. The vapor-liquid coexistence curve at constant composition near the mixture critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.2670 and 0.6648 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R134a mixture is correlated as a function of composition.

Higashi, Yukihiro [Iwaki Meisei Univ., Chuodai, Iwaki (Japan). Dept. of Mechanical Engineering

1999-03-01

143

Sample Loading and Accelerated Cooling of Cryogen-free Dilution Refrigerators  

NASA Astrophysics Data System (ADS)

We present results from system tests of top and bottom loading cryogen-free dilution refrigerators which enable cool-down times from room temperature to mK temperatures in 6 to 8 hours. The loading and unloading processes take only a few minutes to perform and the cooling procedure is fully automated. Sample temperatures of less than 10 mK have been achieved with up to 8 coaxial cables and 25 DC-wires connected to the sample holder. We also present cool-down tests of a beam line dilution refrigerator with a 35 kg mass installed on the mixing chamber. A heat pipe was developed to accelerate the cooling of large experimental payloads and the mass was cooled from room temperature to 30 mK in less than 28 hours.

Teleberg, G.; Matthews, A. J.; Batey, G.; Elford, J.

2012-12-01

144

Simulation of chip-size electrocaloric refrigerator with high cooling-power density  

NASA Astrophysics Data System (ADS)

The large electrocaloric effect that found in ferroelectric polymers creates unique opportunity for developing high performance chip scale solid state refrigerator. This letter presents a finite volume simulation study and shows that by employing solid state regenerators and the micro-heat pumping mechanism used in the thermoacoustic cooling, a compact Electrocaloric Oscillatory Refrigeration (ECOR) device can be realized. The simulation results demonstrate that a 1 cm-long ECOR device can provide 9 W/cm3 volumetric cooling power density at 20 K temperature span. By tuning the device parameters in the model, the ECOR can reach more than 50% of the Carnot efficiency.

Gu, Haiming; Craven, Brent; Qian, Xiaoshi; Li, Xinyu; Cheng, Ailan; Zhang, Q. M.

2013-03-01

145

Metered-dose inhaler formulations with beclomethasone-17,21-dipropionate using the ozone friendly propellant R 134a.  

PubMed

Metered-dose inhalers (MDI) are the most widely prescribed devices in the treatment of lung diseases but the continued use of chlorofluorocarbons (CFC) as propellants has made them unpopular due to their influence on the stratospheric ozone layer. The purpose of this study was to show possibilities of formulating beclomethasone-17,21-dipropionate (BDP) with the alternative propellant R 134a as a solution or as a suspension-type metered-dose inhaler. Influencing factors such as surfactant concentration, cosolvent content and actuator tube design were investigated. Metered-dose inhaler formulations were manufactured using a pressure filling technique. The resulting formulations were characterized with regard to their emitted fine particle fraction using the two-stage impinger, BP 93. Fine particle fraction was found to be independent on the surfactant concentration but highly dependent on the cosolvent content and the actuator tube design. In vitro fine particle fractions of 50% were obtained with solution phase MDIs. Formulating BDP as a suspension resulted in unstable dispersions in most cases because of the partial solubility of the drug in the liquified propellant. Stable suspension formulations gave an in vitro fine particle fraction of about 30%. A comparison with established marketed BDP suspension formulations which were found to emit a fine particle fraction in the range 10-50% showed the equivalence of the new CFC-free formulations. PMID:9700025

Steckel, H; Müller, B W

1998-07-01

146

A Unique Approach to Power Electronics and Motor Cooling in a Hybrid Electric Vehicle Environment  

SciTech Connect

An innovative system for cooling the power electronics of hybrid electric vehicles is presented. This system uses a typical automotive refrigerant R-134a (1,1,1,2 tetrafluoroethane) as the cooling fluid in a system that can be used as either part of the existing vehicle passenger air conditioning system or separately and independently of the existing air conditioner. Because of the design characteristics, the cooling coefficient of performance is on the order of 40. Because liquid refrigerant is used to cool the electronics directly, high heat fluxes can result while maintaining an electronics junction temperature at an acceptable value. In addition, an inverter housing that occupies only half the volume of a conventional inverter has been designed to take advantage of this cooling system. Planned improvements should result in further volume reductions while maintaining a high power level.

Ayers, Curtis William [ORNL; Hsu, John S [ORNL; Lowe, Kirk T [ORNL; Conklin, Jim [ORNL

2007-01-01

147

Experimental Thermal Conductivity Values for the IUPAC Round-Robin Sample of 1,1,1,2-Tetrafluoroethane (R134a).  

National Technical Information Service (NTIS)

Experimental measurements are reported for the thermal conductivity of 1,1,1,2-tetrafluoroethane (R134a). These measurements were obtained with transient and steady-state hot wires; both bare platinum and anodized tantalum hot wires were used to examine e...

R. A. Perkins A. Laesecke J. Howley M. L. V. Ramires A. N. Gurova L. Cusco

2000-01-01

148

Cooling of superconducting devices by liquid storage and refrigeration unit  

DOEpatents

A system is disclosed for cooling superconducting devices. The system includes a cryogen cooling system configured to be coupled to the superconducting device and to supply cryogen to the device. The system also includes a cryogen storage system configured to supply cryogen to the device. The system further includes flow control valving configured to selectively isolate the cryogen cooling system from the device, thereby directing a flow of cryogen to the device from the cryogen storage system.

Laskaris, Evangelos Trifon; Urbahn, John Arthur; Steinbach, Albert Eugene

2013-08-20

149

A SOLAR EJECTOR COOLING SYSTEM USING REFRIGERANT R141b  

Microsoft Academic Search

A high-performance solar ejector cooling system using R141b as the working fluid was developed. We obtain experimentally a COP of 0.5 for a single-stage ejector cooling system at a generating temperature of 90°C, condensing temperature of 28°C, and an evaporating temperature 8°C. For solar cooling application, an optimum overall COP can be obtained around 0.22 at a generating temperature of

B. J Huang; J. M Chang; V. A Petrenko; K. B Zhuk

1998-01-01

150

THERMODYNAMIC EVALUATION OF FIVE ALTERNATIVE REFRIGERANTS IN VAPOR-COMPRESSION CYCLES  

EPA Science Inventory

The paper gives results of a thermodynamic evaluation of five alternative refrigerants in a vapor-compression refrigeration cycle, utilizing throttling, super-heating, and combined throttling and superheating. ive alternative refrigerants (R32, R125, R134a, R143a, and R152a) were...

151

Characterization of diabatic two-phase flows in microchannels: Flow parameter results for R-134a in a 0.5 mm channel  

Microsoft Academic Search

An optical measurement method for two-phase flow pattern characterization in microtubes has been utilized to determine the frequency of bubbles generated in a microevaporator, the coalescence rates of these bubbles and their length distribution as well as their mean velocity. The tests were run in a 0.5mm glass channel using saturated R-134a at 30°C (7.7bar). The optical technique uses two

Rémi Revellin; Vincent Dupont; Thierry Ursenbacher; John R. Thome; Iztok Zun

2006-01-01

152

Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane + 1,1,1,2-tetrafluoroethane (R125\\/R134a)  

Microsoft Academic Search

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1,2-tetrafluoroethane (R134a) was measured along four isotherms between 283 K and 313 K. The vapor-liquid coexistence curve at constant composition near the mixture critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.2670 and 0.6648 mole fraction of R125 were determined from the

Yukihiro Higashi; Yukihiro

1999-01-01

153

Supercritical fluid extraction of polybrominated diphenyl ethers (PBDEs) from house dust with supercritical 1,1,1,2-tetrafluoroethane (R134a).  

PubMed

The extraction of polybrominated diphenyl ethers (PBDEs) from SRM 2585 (Organic Contaminants in House Dust) was investigated using supercritical fluid R134a as an extraction solvent. Three methods of dust extraction were studied: (1) extraction of dry dust, (2) extraction of dry dust dispersed on Ottawa sand and (3) extraction of dust wet with dichloromethane. For each of the three sample preparation methods, extracts at three temperatures (110, 150, and 200 degrees C) above the critical temperature of R134a were performed. Eight PBDE congeners (BDE-28, -47, -99, 100, -153, -154, -183, and -209) in the SFE extracts were analyzed by liquid chromatography negative-ion atmospheric pressure photoionization tandem mass spectrometry (LC/NI-APPI/MS/MS). The optimum extraction of PBDEs from house dust using supercritical R134a is obtained when the dust is pre-wet with dichloromethane prior to extraction to swell the dust. For all sample preparation methods, higher temperatures afforded higher percent recoveries of the eight PBDE congeners. Only a combination of high-temperature (200 degrees C) and pre-wetting the dust with dichloromethane produced high recovery of the environmentally important, fully brominated PBDE congener, BDE-209. PMID:20006061

Calvosa, Frank C; Lagalante, Anthony F

2010-01-15

154

The Prospects of Alternatives to Vapor Compression Technology for Space Cooling and Food Refrigeration Applications  

SciTech Connect

Five alternatives to vapor compression technology were qualitatively evaluated to determine their prospects for being better than vapor compression for space cooling and food refrigeration applications. The results of the assessment are summarized in the report. Overall, thermoacoustic and magnetic technologies were judged to have the best prospects for competing with vapor compression technology, with thermotunneling, thermoelectric, and thermionic technologies trailing behind in that order.

Brown, Daryl R.; Dirks, James A.; Fernandez, Nicholas; Stout, Tyson E.

2010-03-31

155

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

156

The Prospects of Alternatives to Vapor Compression Technology for Space Cooling and Food Refrigeration Applications  

SciTech Connect

This article identifies and describes five alternative cooling technologies (magnetic, thermionic, thermoacoustic, thermoelectric, and thermotunnel) and qualitatively assesses the prospects of each technology relative to vapor compression for space cooling and food refrigeration applications. Assessment of the alternatives was based on the theoretical maximum % of Carnot efficiency, the current state of development, the best % of Carnot efficiency currently achieved, developmental barriers, and the extent of development activity. The prospect for each alternative was assigned an overall qualitative rating based on the subjective, composite view of the five characteristics.

Brown, Daryl R.; Stout, Tyson E.; Dirks, James A.; Fernandez, Nicholas

2012-12-01

157

Evaporation heat transfer and friction characteristics of R-134a flowing downward in a vertical corrugated tube  

SciTech Connect

Differently from most previous studies, the heat transfer and friction characteristics of the pure refrigerant HFC-134a during evaporation inside a vertical corrugated tube are experimentally investigated. The double tube test sections are 0.5 m long with refrigerant flowing in the inner tube and heating water flowing in the annulus. The inner tubes are one smooth tube and two corrugated tubes, which are constructed from smooth copper tube of 8.7 mm inner diameter. The test runs are performed at evaporating temperatures of 10, 15, and 20 C, heat fluxes of 20, 25, and 30 kW/m{sup 2}, and mass fluxes of 200, 300, and 400 kg/m{sup 2} s. The quality of the refrigerant in the test section is calculated using the temperature and pressure obtained from the experiment. The pressure drop across the test section is measured directly by a differential pressure transducer. The effects of heat flux, mass flux, and evaporation temperature on the heat transfer coefficient and two-phase friction factor are also discussed. It is found that the percentage increases of the heat transfer coefficient and the two-phase friction factor of the corrugated tubes compared with those of the smooth tube are approximately 0-10% and 70-140%, respectively. (author)

Aroonrat, Kanit; 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 10140 (Thailand)

2011-01-15

158

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

159

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

160

REVISED DRAFT Hydrocarbon Refrigerants in Australian Cars  

Microsoft Academic Search

Australians need car air conditioning and the hydrocarbon (HC) refrig- erant 290\\/600a avoids stratospheric ozone depletion and a typical 15% in- crease in TEWI from R134a leakage and service emissions. From nothing in 1994, Australian HC refrigerant sales have increased to about 5% of their available market in 1998 because costs were kept less than half competing refrigerants. Batches of

Ian Maclaine-cross; Jan Goedhart

161

Cooling performance of hybrid refrigerant of solid nitrogen and small amount of neon for the purpose of HTS power applications  

Microsoft Academic Search

We have investigated cooling performance of a hybrid refrigerant of solid nitrogen and small amount of neon by using a short sample of Bi-2223\\/Ag tape as a cooling target. Solid nitrogen is expected as a heat capacitor for HTS applications operated below triple point temperature of nitrogen, and we have proposed in our previous study a method for overcoming the

K. Higashikawa; T. Nakamura

2009-01-01

162

Effect of pulse tube volume on dynamics of linear compressor and cooling performance in Stirling-type pulse tube refrigerator  

Microsoft Academic Search

In a Stirling-type pulse tube refrigerator (PTR), the pulse tube volume affects the dynamic behavior of a linear compressor as well as the cooling performance of PTR. In this study, PTRs which have different pulse tube volume are tested and simulated. The simulation code is verified with the experimental measurement of piston displacement, pressure wave, input power and cooling capacity.

Junseok Ko; Sangkwon Jeong; Taekyoung Ki

2010-01-01

163

ANALYSING MULTIVARIABLE CONTROL OF REFRIGERATION PLANT USING MATLAB\\/SIMULINK  

Microsoft Academic Search

Little work has been done on the closed loop response of refrigeration plant using the new chlorine-free refrigerants. A simulation model of a water-water refrigeration plant using R134a is developed for the purpose of investigating control system performance. The well-established problem of coupling between the two main regulatory control loops governing evaporator degree-of-superheat and plant capacity is recognised and the

C P Underwood

164

Refrigerant mass migration modeling and simulation for air conditioning systems  

Microsoft Academic Search

Refrigerant mass migration and redistribution are regarded as key factors affecting the cycling performance of air conditioning and refrigeration systems. A dynamic model of an R134a automotive air conditioning system is presented as an example in this paper to capture the refrigerant migration during compressor shut-down and start-up operations. Model validation against experimental data demonstrates the capabilities of the modeling

Bin Li; Steffen Peuker; Predrag S. Hrnjak; Andrew G. Alleyne

2011-01-01

165

Environmental implications of hydrocarbon refrigerants applied to the hermetic compressor  

Microsoft Academic Search

This paper describes the environmental impacts of hydrocarbon refrigerants deployed in the domestic refrigerator hermetic compressor. In-use durability is examined from a tribological viewpoint. Experimental tribological information is presented from physical test procedures involving sliding tests to establish wear mechanisms and friction coefficients within critical components. Hydrocarbon refrigerant R600a is compared with hydroflourocarbon R134a using aluminium on steel samples within

N. P. Garland; M. Hadfield

2005-01-01

166

Kinetic electrocaloric effect and giant net cooling of lead-free ferroelectric refrigerants  

NASA Astrophysics Data System (ADS)

The electrocaloric effect of BaTiO3 multilayer thick film structure was investigated by direct measurement using differential scanning calorimeter. The samples show a giant electrocaloric effect of 0.89 J/g under E=176 kV/cm, which also depends on the varying rate of applied field, following a general power-law relation. Based on the large net-cooling (0.37 J/g) resulting from the difference in the varying rates of rising and falling fields, the kinetic electrocaloric effect provides a solution for the design of refrigeration cycle in ferroelectric microrefrigerator.

Bai, Yang; Zheng, Guang-Ping; Shi, San-Qiang

2010-11-01

167

Measurement and modeling of a large-area normal-metal/insulator/superconductor refrigerator with improved cooling  

NASA Astrophysics Data System (ADS)

In a normal-metal/insulator/superconductor (NIS) tunnel junction refrigerator, the normal-metal electrons are cooled and the dissipated power heats the superconducting electrode. This paper presents a review of the mechanisms by which heat leaves the superconductor and introduces overlayer quasiparticle traps for more effective heat sinking. A comprehensive thermal model is presented that accounts for the described physics, including the behavior of athermal phonons generated by both quasiparticle recombination and trapped quasiparticles. We compare the model to measurements of a large-area (>400?m2) NIS refrigerator with overlayer quasiparticle traps, and demonstrate that the model is in good agreement experiment. The refrigerator IV curve at a bath temperature of 300 mK is consistent with an electron temperature of 82 mK. However, evidence from independent thermometer junctions suggests that the refrigerator junction is creating an athermal electron whose total excitation energy corresponds to a higher temperature than is indicated by the refrigerator IV curve.

O'Neil, Galen C.; Lowell, Peter J.; Underwood, Jason M.; Ullom, Joel N.

2012-04-01

168

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

Microsoft Academic Search

Numerous mixed-gases refrigeration cycle configurations based on Joule–Thomson effects were developed in the past several decades. In this paper, comprehensive thermodynamic analyses were made on two typical cycle configurations to learn their performance for cooling fixed-temperature heat loads. One is the single-stage cycle without phase separators; the other is the auto-cascade refrigeration cycle which has at least one phase separator.

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

2004-01-01

169

Performance prediction of refrigerant-DMF solutions in a single-stage solar-powered absorption refrigeration system at low generating temperatures  

SciTech Connect

A theoretical analysis of the coefficient of performance was undertaken to examine the efficiency characteristics of R22 + DMF, R134a + DMF, R32 + DMF as working fluids, respectively, for a single-stage and intermittent absorption refrigerator which allows the use of heat pipe evacuated tubular collectors. The modeling and simulation of the performance considers both solar collector system and the absorption cooling system. The typical meteorological year file containing the weather parameters for Hangzhou is used to simulate the system. The results show that the system is in phase with the weather. In order to increase the reliability of the system, a hot water storage tank is essential. The optimum ratio of storage tank per solar collector area for Hangzhou's climate for a 1.0 kW system is 0.035-0.043L. Considering the relative low pressure and the high coefficient of performance, R134a + DMF mixture presents interesting properties for its application in solar absorption cycles at moderate condensing and absorbing temperatures when the evaporating temperatures in the range from 278 K to 288 K which are highly useful for food preservation and for air-conditioning in rural areas. (author)

He, L.J. [Institute of Refrigeration and Cryogenics, Zhejiang University, Hangzhou 310027 (China); Institute of Environment and Energy, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Tang, L.M.; Chen, G.M. [Institute of Refrigeration and Cryogenics, Zhejiang University, Hangzhou 310027 (China)

2009-11-15

170

The development of high cooling power and low ultimate temperature superfluid Stirling refrigerators  

NASA Astrophysics Data System (ADS)

The superfluid Stirling refrigerator (SSR) is a recuperative Stirling cycle refrigerator which provides cooling to below 2 K by using a liquid 3He-4He mixture as the working fluid. In 1990, Kotsubo and Swift demonstrated the first SSR, and by 1995, Brisson and Swift had developed an experimental prototype capable of reaching a low temperature of 296 mK. The goal of this thesis was to improve these capabilities by developing a better understanding of the SSR and building SSR's with higher cooling powers and lower ultimate temperatures. This thesis contains four main parts. In the first part, a numerical analysis demonstrates that the optimal design and ultimate performance of a recuperative Stirling refrigerator is fundamentally different from that of a standard regenerative Stirling refrigerator due to a mass flow imbalance within the recuperator. The analysis also shows that high efficiency recuperators remain a key to SSR performance. Due to a quantum effect called Kapitza resistance, the only realistic and economical method of creating higher efficiency recuperators for use with an SSR is to construct the heat exchangers from very thin (12 ?m - 25 ?m thick) plastic films. The second part of this thesis involves the design and construction of these recuperators. This research resulted in Kapton heat exchangers which are leaktight to superfluid helium and capable of surviving repeated thermal cycling. In the third part of this thesis, two different single stage SSR's are operated to test whether the plastic recuperators would actually improve SSR performance. Operating from a high temperature of 1.0 K and with 1.5% and 3.0% 3He-4He mixtures, these SSR's achieved a low temperature of 291 mK and delivered net cooling powers of 3705 ?W at 750 mK, 977 ?W at 500 mK, and 409 ?W at 400 mK. Finally, this thesis describes the operation of three versions of a two stage SSR. Unfortunately, due to experimental difficulties, the merits of a two stage SSR were not demonstrated and further work is still required. However, despite these difficulties, one of the two stage SSR's was able to reach an ultimate low temperature of 248 mK from a high temperature of 1.03 K. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Patel, Ashok B.

171

The maximal cooling power of magnetic and thermoelectric refrigerators with La(FeCoSi)13 alloys  

NASA Astrophysics Data System (ADS)

Using our data on magnetic entropy change ?Sm, adiabatic temperature change ?Tad and heat capacity CH for La(FeCoSi)13 alloys, the upper limit of heat Qc transferred per cycle, and the lowest limit of consumed work Wc were established for magnetic refrigerators operating in ??0H=1.9 T. In order to estimate the cooling power, attributable to thermoelectric refrigerators with La(FeCoSi)13, thermal conductivity ?, resistivity ?, and Seebeck coefficient ? were measured and the maximal cooling power QL, the input power Pi, and coefficient of performance have been calculated.

Skokov, K. P.; Karpenkov, A. Yu.; Karpenkov, D. Yu.; Gutfleisch, O.

2013-05-01

172

Thermodynamic evaluation of five alternative refrigerants in vapor-compression cycles  

Microsoft Academic Search

The paper gives results of a thermodynamic evaluation of five alternative refrigerants in a vapor-compression refrigeration cycle, utilizing throttling, superheating, and combined throttling and superheating. Five alternative refrigerants (R32, R125, R134a, R143a, and R152a) were considered for refrigerants R12, R22, and R502. Thermodynamically, the best alternative for R12 in a wide range of evaporation and condensing temperatures is R152a, which

G. S. Kazachki; C. L. Gage

1991-01-01

173

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

174

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

175

The Cost of Helium Refrigerators and Coolers for SuperconductingDevices as a Function of Cooling at 4 K  

SciTech Connect

This paper is an update of papers written in 1991 and in1997 by Rod Byrns and this author concerning estimating the cost ofrefrigeration for superconducting magnets and cavities. The actual costsof helium refrigerators and coolers (escalated to 2007 dollars) areplotted and compared to a correlation function. A correlation functionbetween cost and refrigeration at 4.5 K is given. The capital cost oflarger refrigerators (greater than 10 W at 4.5 K) is plotted as afunction of 4.5-K cooling. The cost of small coolers is plotted as afunction of refrigeration available at 4.2 K. A correlation function forestimating efficiency (percent of Carnot) of both types of refrigeratorsis also given.

Green, Michael A.

2007-08-27

176

Flow boiling heat transfer of R134a and R404A in a microfin tube at low mass fluxes and low heat fluxes  

NASA Astrophysics Data System (ADS)

An experimental investigation of flow boiling heat transfer in a commercially available microfin tube with 9.52 mm outer diameter has been carried out. The microfin tube is made of copper with a total fin number of 55 and a helix angle of 15°. The fin height is 0.24 mm and the inner tube diameter at fin root is 8.95 mm. The test tube is 1 m long and is electrically heated. The experiments have been performed at saturation temperatures between 0 and -20°C. The mass flux was varied between 25 and 150 kg/m2s, the heat flux from 15,000 W/m2 down to 1,000 W/m2. All measurements have been performed at constant inlet vapour quality ranging from 0.1 to 0.7. The measured heat transfer coefficients range from 1,300 to 15,700 W/m2K for R134a and from 912 to 11,451 W/m2K for R404A. The mean heat transfer coefficient of R134a is in average 1.5 times higher than for R404A. The mean heat transfer coefficient has been compared with the correlations by Koyama et al. and by Kandlikar. The deviations are within ±30% and ±15%, respectively. The influence of the mass flux on the heat transfer is most significant between 25 and 62.5 kg/m2s, where the flow pattern changes from stratified wavy flow to almost annular flow. This flow pattern transition is shifted to lower mass fluxes for the microfin tube compared to the smooth tube.

Spindler, Klaus; Müller-Steinhagen, Hans

2009-05-01

177

Current and future miniature refrigeration cooling technologies for high power microelectronics  

Microsoft Academic Search

Utilizing refrigeration may provide the only means by which future high-performance electronic chips can be maintained below predicted maximum temperature limits. Widespread application of refrigeration in electronic packaging will remain limited, until the refrigerators can be made sufficiently small so that they can be easily incorporated within the packaging. A review of existing microscale and mesoscale refrigeration systems revealed that

Patrick E. Phelan; Victor A. Chiriac; Tien-Yu Tom Lee

2002-01-01

178

Voltage-driven superconducting weak link as a refrigerator for cooling of nanomechanical vibrations  

NASA Astrophysics Data System (ADS)

We consider a new type of cooling mechanism for a suspended nanowire acting as a weak link between two superconductive electrodes. By applying a bias voltage over the system, we show that the system can be viewed as a refrigerator for the nanomechanical vibrations, where energy is continuously transferred from the vibrational degrees of freedom to the extended quasiparticle states in the leads through the periodic modulation of the inter-Andreev level separation. The necessary coupling between the electronic and mechanical degrees of freedom responsible for this energy-transfer can be achieved both with an external magnetic or electrical field, and is shown to lead to an effective cooling of the vibrating nanowire. Using realistic parameters for a suspended nanowire in the form of a metallic carbon nanotube we analyze the evolution of the density matrix and demonstrate the possibility of cooling the system down to a stationary vibron population of ~0.1. Furthermore, it is shown that the stationary occupancy of the vibrational modes of the nanowire can be directly probed using the dc current responsible for carrying away the absorbed energy from the vibrating nanowire.

Sonne, G.; Peña-Aza, M. E.; Shekhter, R. I.; Gorelik, L. Y.; Jonson, M.

2010-10-01

179

Dipole moments of seven partially halogenated ethane refrigerants  

Microsoft Academic Search

Dielectric constant measurements have been performed on seven partially halogenated ethanes, currently being considered as alternative refrigerants, in the gaseous state over the range 305-415 K in order to determine their dipole moments. Argon was also studied to test the apparatus. Five of the refrigerants have temperature-independent moments: R125 (CFâCHFâ), μ = 1.563 {plus minus} 0.005 D; R134a (CFâCHâF), μ

Christopher W. Meyer; Graham Morrison

1991-01-01

180

Numerical analysis of choked refrigerant flow in adiabatic capillary tubes  

Microsoft Academic Search

This paper presents a homogeneous simulation model for choked flow conditions for pure refrigerants (R134a, R600a) in adiabatic capillary tubes. The model is based on the first principles of thermodynamics and fluid mechanics and some empirical relations. This study presents a fresh-look at the classical fluid flow problem, known as ‘Fanno flow’ for refrigerant flow in capillary tubes. A new

P. K. Bansal; G. Wang

2004-01-01

181

Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat  

SciTech Connect

BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

None

2010-09-01

182

Determination of the refrigerating capacity of cryogenic gas machines for cooling current leads containing high-temperature superconductors  

NASA Astrophysics Data System (ADS)

A method of calculation of current leads containing high-temperature semiconductors and cooled by cryogenic gas machines (cryocoolers) has been proposed. The method is based on subdivision of current leads into individual portions (sections) differing in the character of traversal of the current and cooling conditions. The results of the change in the required refrigerating capacity of the coolers operating at different temperature levels as a function of the length and arrangement of the sections have been shown. The distinctive features of the variation in the temperature and the heat flux along cryocooler-cooled current leads have been analyzed.

Buyanov, Yu. L.; Veselovskii*, A. S.; Baev, V. P.

2011-05-01

183

Effectiveness of a head wash cooling protocol using non-refrigerated water in reducing heat stress.  

PubMed

Envisioning a cooling method and aiming at maximum feasibility and simplicity, we designed an experimental intervention-control study based on non-refrigerated water usage, consisting of pouring 2 l of 23.0 degrees C water simultaneously on head and hands for one minute, after every 20 min of exertion. The subjects were 11 fit male individuals between 19 and 26 yr old. Each individual participated in one control and one intervention measurement in a climatic chamber at 35 degrees C and 60% humidity (31.5 degrees C WBGT) on different days. Heart rate, rectal, esophageal, skin and external ear canal temperatures were monitored constantly. Each experiment consisted of 10 min of basal recording followed by 3 intervals of 20 min of cycling and 15 min of rest. Stabilometry and visual reaction time tests were performed before and after each resting period. A questionnaire evaluating equilibrium, concentration, alertness and tiredness was administered at the beginning and at the end of every experiment. Paired t-test analysis revealed significant improvements in subjective parameters (all p<0.05), as well as skin (p<0.05), external ear canal (p<0.01) and esophageal (p<0.05) temperatures during the rest periods. Repeated measurement analysis of variance revealed significant cooling in all the aforementioned temperatures except the esophageal temperature (p=0.28). Other parameters were not significantly different. Our findings indicate that this method has subjective and physiologic positive effects, and thus can be used as a complementary low cost method to cool subjects safely. PMID:18413974

Fujii, Ronaldo Kenzou; Horie, Seichi; Tsutsui, Takao; Nagano, Chikage

2008-04-15

184

Cooling performance of hybrid refrigerant of solid nitrogen and small amount of neon for the purpose of HTS power applications  

NASA Astrophysics Data System (ADS)

We have investigated cooling performance of a hybrid refrigerant of solid nitrogen and small amount of neon by using a short sample of Bi-2223/Ag tape as a cooling target. Solid nitrogen is expected as a heat capacitor for HTS applications operated below triple point temperature of nitrogen, and we have proposed in our previous study a method for overcoming the problem of its thermal contact with a cooling target with the aid of small amount of liquid neon. This paper discusses the phase state as well as the quantity of neon required for such an improvement. Nitrogen gas was introduced into a sample chamber through a mass flow controller, and then was liquefied and solidified by a Gifford-McMahon cryocooler. After that, in order to improve thermal contact of the solid nitrogen with the sample, neon gas was also introduced into the chamber at 25 K where neon can be liquefied. Cooling performance of such a hybrid refrigerant with different inputs of neon was evaluated by measuring temperature rise of the sample with the transportation of overcurrent. As a result, neon could suppress the temperature rise even in gas state, and the existence of liquid neon could additionally suppress the temperature rise. Furthermore, the required proportion of the liquid neon to the solid nitrogen was very small. From these results, we concluded that introducing neon until neon can be liquefied was the best way to make the most of the potential of the hybrid refrigerant.

Higashikawa, K.; Nakamura, T.

2009-11-01

185

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

186

Thermodynamic cycle performances analysis of high temperature refrigerants in a multi-stage heat pump system  

Microsoft Academic Search

Based on the select criteria of the refrigerants for high temperature heat pump system, six selected refrigerants, R245fa, R245ca, R236ea, R123, R600 and R134a are used as working fluid of the high temperature heat pump. Three kinds of multi-stage refrigeration circulations, i.e. two-stage compression cycle with one subcooler, two-stage compression cycle with one heat regenerator and one flash tank and

Ma Liangdong; Zhang Jili; Zhang Shuyan

2010-01-01

187

Effect of flow topology on the calculation of two-phase frictional multipliers in uniformly heated flow of R-134a in a rectangular duct  

SciTech Connect

The two-phase frictional multipliers for SUVA R-134a flowing in a rectangular duct (with D{sub H} = 4.8 mm) have been measured for three nominal system pressures (0.88, 1.34 and 2.34 MPa) and four nominal mass fluxes (510, 1020 and 1740, 2040 kg/m{sup 2}/s) under uniform heat flux conditions. The data is compared with adiabatic data previously taken at similar flow conditions, as well as with several classical multiplier correlations. The comparisons reveal a strong effect of pressure and mass flux on the flow topology and, by extension, a large effect on the calculation of acceleration and frictional pressure drop components. For this fluid and this geometry, entrainment and fluid separation is enhanced at higher pressures and mass flux such that most of the liquid exists in the test section edges and as dispersed droplets in the core. For these cases, the classical simplified approach to calculate acceleration pressure drop fails to adequately predict the acceleration component and leads to erroneous calculations of frictional pressure drop from the measured total pressure drop. Best estimates of the true acceleration component are given, based on void profiles measured with a gamma densitometer system, comparisons to the adiabatic data, and recasting the data in terms of the total pressure drop multiplier as a function of the Martinelli parameter, X{sub tt}. (author)

Vassallo, Peter; Kevin Cope, W.; Smith, Walter C. [Bechtel Marine Propulsion Corporation, Niskayuna, NY 12309 (United States)

2010-11-15

188

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

Microsoft Academic Search

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

Ammar Bahman

2011-01-01

189

A Rapid Turnaround Two-Stage Adiabatic Demagnetization Refrigerator for Cooling to 50 mK  

NASA Astrophysics Data System (ADS)

Many research and development programs require rapid access to very low temperatures (~50 mK). For detector development, relatively large experiment volumes are also needed for tests involving integrated detectors and readout amplifiers (which may need to be stationed at a different temperature). To provide this capability in a versatile, fast turnaround system, we have constructed a two-stage adiabatic demagnetization refrigerator (ADR) that is operated in a simple bucket-style dewar. The ADR/cryostat is separated into two concentric inserts; the outer insert supports two 3.3 T magnets, magnet leads and magnetic shielding, and the inner one consists of a hermetic experiment volume coupled to the ADR's salt pills and heat switches. The magnet insert remains in the dewar at all times, while the ADR insert may be inserted and removed even when the dewar is cold. The cooldown from room temperature takes less than 1.5 hours, and cycling of the ADR as little as 30 minutes. Future tests will investigate the use of neon exchange gas to accelerate cooling of the ADR and more thermally isolated components such as wiring and structural supports. Design and operation of the system are discussed.

Shirron, P. J.; Dipirro, M. J.; Panek, J. S.; Francis, J. J.; Warner, B. A.; Jackson, M. L.

2006-04-01

190

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

191

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

192

Experimental investigation of velocity and length of elongated bubbles for flow of R-134a in a 0.5 mm microchannel  

SciTech Connect

The length and velocity of elongated bubbles have been experimentally investigated for R-134a flowing in a 0.5 mm microchannel, where 440 experimental data points were obtained at the exit of a microevaporator using an optical laser measurement technique. The variation of the elongated bubble velocity u{sub v} as a function of its length L{sub v} shows firstly, a nearly linear increase of u{sub v} with L{sub v} and secondly, a region where the velocity tends towards a plateau and where it varies little with further increase in length. This behavior is the starting point to explain merging between elongated bubbles in microchannels during flow boiling. No influence of a small variation in the inlet subcooling (ranging from 2 to 5 C) and the microevaporator length (ranging from 30 to 70 mm) was observed on the bubble velocity and the bubble length. On the other hand, when decreasing the saturation temperature, the bubble length and the bubble velocity both increased due to the decrease in the vapor density. Almost 92% of the new database obtained here is predicted by the elongated bubble velocity model of Agostini et al. [B. Agostini, R. Revellin, J.R. Thome, Elongated bubbles in microchannels. Part I: Experimental study and modelisation of elongated bubble velocity. Int. J. Multiphase Flow, in press] within a {+-}20% error band. Furthermore, this model shows that during diabatic flow boiling of elongated bubbles in horizontal microchannels, the drift flux distribution parameter C is close to unity and the drift velocity is not necessarily equal to zero as predicted by the original drift flux model of Zuber and Findlay [N. Zuber, J.A. Findlay, Average volumetric concentration in two-phase flow systems. J. Heat Transfer 87 (1965) 458-463]. Rather the drift velocity can deviate substantially from the average bubble velocity given by the homogeneous model. (author)

Revellin, Remi [Centre de Thermique de Lyon (CETHIL), UMR 5008 CNRS-INSA-Univ. Lyon 1, Bat. Sadi Carnot, INSA-Lyon, F-69621 Villeurbanne Cedex (France); Agostini, Bruno [ABB Switzerland Ltd., Corporate Research, Segelhofstrasse 1 K/P.O. Box, CH-5405 Baden 5 Daettwil (Switzerland); Ursenbacher, Thierry; Thome, John R. [EPFL STI ISE LTCM, ME G1 464, Station 9, CH-1015 Lausanne (Switzerland)

2008-01-15

193

Horizontal Convective Condensation of Alternative Refrigerants within a Micro-Fin Tube.  

National Technical Information Service (NTIS)

This paper presents local convective condensation measurements for four refrigerants: R134a, R410A(R32/R125, 50/50 % mass), R125, and R32 in a micro-fin tube. Both heat transfer and pressure drop measurements are provided. The heat transfer degradation as...

M. A. Kedzierski J. M. Goncalves

1997-01-01

194

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

195

An Evaluation of Small Closed-Cycle Cryogenic Refrigerators as Cooling Devices for Infrared Detectors.  

National Technical Information Service (NTIS)

Miniature closed-cycle cryogenic refrigerators are required to maintain photoconductive and photovoltaic infrared detectors used in airborne passive infrared surveillance devices at their proper operating temperatures in the range of 21 degrees to 90 degr...

E. A. Mebus N. S. Fitti

1969-01-01

196

Airborne exposure to trihalomethanes from tap water in homes with refrigeration-type and evaporative cooling systems.  

PubMed

This study evaluates airborne concentrations of common trihalomethane compounds (THM) in selected living spaces of homes supplied with chlorinated tap water containing >85 ppb total THM. Three small homes in an arid urban area were selected, each having three bedrooms, a full bath, and approximately 1000 square feet; two homes had standard (refrigeration-type) central air conditioning and the third had a central evaporative cooling system ("swamp cooler"). A high-end water-use pattern was used at each home in this exposure simulation. THM were concurrently measured on 4 separate test days in tap water and air in the bathroom, living room, the bedroom closest to the bathroom, and outside using Summa canisters. Chloroform (trichloromethane, TCM), bromodichloromethane (BDCM), and dibromochloromethane (DBCM) concentrations were quantified using U.S. EPA Method TO-14. The apparent volatilization fraction consistently followed the order: TCM > BDCM > DBCM. Relatively low airborne THM concentrations (similar to outdoors) were found in the living room and bedroom samples for the home with evaporative cooling, while the refrigeration-cooled homes showed significantly higher THM levels (three- to fourfold). This differential remained after normalizing the air concentrations based on estimated THM throughput or water concentrations. These findings indicate that, despite higher throughput of THM-containing water in homes using evaporative coolers, the higher air exchange rates associated with these systems rapidly clears THM to levels similar to ambient outdoor concentrations. PMID:15799243

Kerger, Brent D; Suder, David R; Schmidt, Chuck E; Paustenbach, Dennis J

2005-03-26

197

Materials compatibility and lubricants research on CFC-refrigerant substitute: Miscibility of lubricants with refrigerants  

SciTech Connect

During this reporting period, modifications were made to the experimental apparatus in preparation for performing the experiments required in this project. In addition, new procedures for charging the lubricant and refrigerant into the cells for high temperature tests have been adopted. All of the refrigerants (10 different types) and lubricants (seven different types) have been ordered from the manufacturers. To date, the data obtained includes that for R-134a and four lubricants, namely, two esters and two polypropylene glycols (PAGs). Methods for quantifying immiscibility based on observation by different lab workers have been developed.

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

1992-04-01

198

X-ray investigation of a domestic refrigerator. Observations at 25°C ambient temperature  

Microsoft Academic Search

In this study, the transient behavior of a domestic refrigerator is investigated by the use of an X-ray system. The studies are made on a two-door upright freezer with a volume of 435 liters, and which has an automatic defrost feature. The refrigerant is R134a. During the experimental study, ambient temperature is held at 25±2 °C. Real time X-ray video images

Cemil Inan; Turgay Gonul; M. Yalcin Tanes

2003-01-01

199

Phase equilibria of some alternative refrigerants hydrates and their mixtures using for cool storage materials  

Microsoft Academic Search

Electric power demand for residential air-conditioning has been increasing in Japan. Development of cool storage systems which shifts this demand to off-peak period and contributes to the load leveling of power generation is necessary. The hydrate cool storage system is the suitable cool storage system because its cool storage density is large and chiller efficiency is high. In this study,

Takaji Akiya; Tomio Shimazaki; Masaru Oowa; Masaru Nakaiwa; Takashi Nakane; Toshikatsu Hakuta; Mitsuharu Matsuo; Yuji Yoshida

1997-01-01

200

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

201

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

202

Superfluid stirling refrigerator: A new method for cooling below 1 Kelvin  

SciTech Connect

We have invented and built a new type of cryocooler, which we call the superfluid Stirling refrigerator (SSR). The first prototype reached 0.6 K from a starting temperature of 1.2 K. The working fluid of the SSR is the {sup 3}He solute in a superfluid {sup 3}He--{sup 4}He solution. At low temperatures, the superfluid {sup 4}He is in its quantum ground state, and therefore is thermodynamically inert, while the {sup 3}He solute has the thermodynamic properties of a dense ideal gas. Thus, in principle, any refrigeration cycle that can use an ideal gas can also use the {sup 3}He solute as working fluid. In our SSR prototype, bellows-sealed superleak pistons driven by a room-temperature camshaft work on the {sup 3}He solute. Ultimately, we anticipate elimination of moving parts by analogy with pulse-tube refrigeration. 15 refs., 6 figs.

Kotsubo, V.; Swift, G.W.

1990-01-01

203

Generalized Pressure Drop Correlation for Evaporation and Condensation of Alternative Refrigerants in Smooth and Micro-Fin Tubes.  

National Technical Information Service (NTIS)

This paper presents a pressure drop correlation for evaporation and condensation in smooth and micro-fin tubes. The correlation was developed from a database consisting of the following pure and mixed refrigerants: R125, R134a, R32, R410A (R32/R125 50/50 ...

H. Y. Choi M. A. Kedzierski P. A. Domanski

1999-01-01

204

The Use of Water Vapor as a Refrigerant: Impact of Cycle Modifications on Commercial Viability  

SciTech Connect

This project investigated the economic viability of using water as the refrigerant in a 1000-ton chiller application. The most attractive water cycle configuration was found to be a flash-intercooled, two-stage cycle using centrifugal compressors and direct contact heat exchangers. Component level models were developed that could be used to predict the size and performance of the compressors and heat exchangers in this cycle as well as in a baseline, R-134a refrigeration cycle consistent with chillers in use today. A survey of several chiller manufacturers provided information that was used to validate and refine these component models. The component models were integrated into cycle models that were subsequently used to investigate the life-cycle costs of both an R-134a and water refrigeration cycle. It was found that the first cost associated with the water as a refrigerant cycle greatly exceeded the savings in operating costs associated with its somewhat higher COP. Therefore, the water refrigeration cycle is not an economically attractive option to today's R-134a refrigeration system. There are a number of other issues, most notably the requirements associated with purging non-condensable gases that accumulate in a direct contact heat exchanger, which will further reduce the economic viability of the water cycle.

Brandon F. Lachner, Jr.; Gregory F. Nellis; Douglas T. Reindl

2004-08-30

205

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

206

Robie House. Phase II report. Recommendations for cooling and ventilation, restoration of doors and windows, refrigerated cooling retrofit  

SciTech Connect

The purpose of this effort is to provide the building owner, the University of Chicago, with recommendations for cooling. Natural ventilation is the preferred method as long as it can meet the needs of a modern office. This is especially attractive given the natural cooling design features mentioned by Frank Lloyd Wright scholars and confirmed by this research.

Not Available

1986-04-30

207

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

208

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

209

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

210

Experimental performance of ozone-safe alternative refrigerants  

SciTech Connect

Several compounds proposed as near-term or longer range substitutes for the regulated chlorofluorocarbon (CFC) refrigerants were tested in a breadboard vapor-compression circuit, and their performance was evaluated relative to more commonly used refrigerants. The limited physical property information available in the literature for these alternative compounds was used to fit an equation of state so coefficients of performance (COP) and capacities calculated from refrigerant property subroutines could be compared to those obtained experimentally. Comparisons of measured and modeled performance are given for 11 alternatives and for R22, R12, ad R11 Estimates of compressor efficiency with each refrigerant are provided. Several of the alternatives exhibited better performance than the more widely used refrigerants at some or all of the conditions tested. Ozone-safe, alternative refrigerants that performed better than CFC counterparts-at selected conditions are R152a, R143a, R134a, and R142b.

Sand, J.R.; Vineyard, E.A. (Oak Ridge National Lab., Oak Ridge, TN (US)); Nowak, R.J. (Purdue Univ., West Lafayette, IN (US))

1990-01-01

211

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

212

Performance test of a refrigerator cooled magnet fabricated using Bi2212 multilayer superconducting tapes  

Microsoft Academic Search

A stacked pancake coil was fabricated by Ag-alloy sheathed Bi-2212 multilayer tapes and tested using a refrigerator. The magnet consisted of ten double pancakes wound with 100 m class tapes. The Ic values of the tapes varied from 80 A to 150 A at 4.2 K and 10 T because of the scattering of the thickness in the superconducting layers.

T. Hasegawa; Y. Hikichi; T. Koizumi; N. Ohtani; H. Kurnakura; H. Kitaguchi; K. Togano

1999-01-01

213

On-Chip Two-Phase Cooling With Refrigerant 85 $\\\\mu{\\\\rm m}$Wide Multi-Microchannel Evaporator Under Hot-Spot Conditions  

Microsoft Academic Search

Hot-spots are present in micro-electronics and are challenging to cool effectively. This paper presents highly nonuniform heat flux measurements obtained for a pseudo-CPU with 35 local heaters and temperature sensors cooled by a silicon multi-microchannel evaporator with 85 $\\\\mu{\\\\rm m}$ wide and 560 $\\\\mu{\\\\rm m}$ high channels separated by 46 $\\\\mu{\\\\rm m}$ wide fins. A low pressure dielectric refrigerant, R245fa,

Etienne Costa-Patry; Stefano Nebuloni; Jonathan Olivier; John Richard Thome

2012-01-01

214

Pressure drop during condensation of refrigerants in pipe minichannels  

NASA Astrophysics Data System (ADS)

The present paper describes results of experimental investigations of pressure drop during the condensation of R134a, R404a and R407C refrigerants in pipe minichannels with internal diameter 0.31-3.30 mm. The results concern investigations of the mean and local pressure drop in single minichannels. The results of experimental investigations were compared with the calculations according to the correlations proposed by other authors. A pressure drop during the condensation of refrigerants is described in a satisfactory manner with Friedel and Garimella correlations. On the basis of the experimental investigations, the authors proposed their own correlation for calculation of local pressure drop during condensation in single minichannels.

Bohdal, Tadeusz; Charun, Henryk; Sikora, Ma?gorzata

2012-08-01

215

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

216

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

217

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

218

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

219

Kinetic electrocaloric effect and giant net cooling of lead-free ferroelectric refrigerants  

Microsoft Academic Search

The electrocaloric effect of BaTiO3 multilayer thick film structure was investigated by direct measurement using differential scanning calorimeter. The samples show a giant electrocaloric effect of 0.89 J\\/g under E=176 kV\\/cm, which also depends on the varying rate of applied field, following a general power-law relation. Based on the large net-cooling (0.37 J\\/g) resulting from the difference in the varying

Yang Bai; Guang-Ping Zheng; San-Qiang Shi

2010-01-01

220

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

221

A survey of current worldwide research on the thermophysical properties of alternative refrigerants  

Microsoft Academic Search

The survey represents an exhaustive compilation of the research activities throughout the world concerned with either measurements or correlations of the thermophysical properties of alternative refrigerants. The properties covered include thermodynamic, transport, phase equilibria, and other properties such as dielectric constant and refractive index. The survey included a wide range of fluids (including R23, R32, R125, R143a, R22, R134a, R152a,

M. O. McLinden; W. M. Haynes; J. T. R. Watson; K. Watanabe

1991-01-01

222

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

223

Prediction of two-phase pressure gradients of refrigerants in horizontal tubes  

Microsoft Academic Search

Two-phase pressure drop data were obtained for evaporation in two horizontal test sections of 10.92 and 12.00 mm diameter for five refrigerants (R-134a, R-123, R-402A, R-404A and R-502) over mass velocities from 100 to 500 kg\\/m2 s and vapor qualities from 0.04 to 1.0. These data have then been compared against seven two-phase frictional pressure drop prediction methods. Overall, the

M. B. Ould Didi; N. Kattan; J. R. Thome

2002-01-01

224

Experimental Study on Condensation of Pure Refrigerants in Horizontal Micro-fin Tubes  

NASA Astrophysics Data System (ADS)

This paper presents the heat transfer and pressure drop correlations for condensation in micro-fin tubes. Experimental data for eleven micro-fin tubes with different fin dimensions were used, and the refrigerants tested were R22, R123 and R134a. The predicted results using new correlations show good agreement with experimental results within an absolute deviation of ±30%. Experimental results for the micro-fin tubes were also compared with previous correlations for micro-fin Tubes.

Yonemoto, Ryuichiro; Koyama, Shigeru

225

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

226

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

227

Materials compatibility and lubricants research on CFC-refrigerant substitute: Miscibility of lubricants with refrigerants. Quarterly report, 6 February 1992--31 March 1992  

SciTech Connect

During this reporting period, modifications were made to the experimental apparatus in preparation for performing the experiments required in this project. In addition, new procedures for charging the lubricant and refrigerant into the cells for high temperature tests have been adopted. All of the refrigerants (10 different types) and lubricants (seven different types) have been ordered from the manufacturers. To date, the data obtained includes that for R-134a and four lubricants, namely, two esters and two polypropylene glycols (PAGs). Methods for quantifying immiscibility based on observation by different lab workers have been developed.

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

1992-04-01

228

Cooling and heating apparatus  

Microsoft Academic Search

This patent describes an energy transfer apparatus for transferring energy from and to a source liquid to heat and cool a facility, the apparatus comprising: means for providing a refrigerant cycle including means for evaporating refrigerant, means for condensing refrigerant and means for producing a phase change in the refrigerant; means for cooling air; means for providing a single continuous

Dittell

1987-01-01

229

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

230

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

231

A generalized equation for the surface tension of refrigerants  

Microsoft Academic Search

This work presents a literature survey of the available data of the experimental surface tension data for refrigerants. The experimental data were collected for the following pure fluids: R11, R12, R13, R13B1, R14, R21, R22, R23, R32, R113, R114, R115, R123, R123a, R124, R125, R134, R134a, R141b, R143a, R152a, R218, R225ca, R225cb, R227ea, R236ea, R236fa, R245ca, R245fa, R365mfc, R846, and

Giovanni Di Nicola; Matteo Moglie

2011-01-01

232

Measurements of viscosity of refrigerants in the vapor phase  

SciTech Connect

Measurements of the viscosity of refrigerants R124, R125, R134a, and R152a in the vapor phase are presented. The measurements, performed in a new vibrating-wire instrument, cover a temperature range from 273 to 333 K from about atmospheric pressure up to below the saturation pressure. The uncertainty of the reported values is estimated to be better than {+-}1%. Comparison with measurements of other investigators reveals a lack of reliable data in the vapor region for these compounds.

Assael, M.J.; Polimatidou, S.K. [Aristotle Univ., Thessaloniki (Greece). Faculty of Chemical Engineering

1997-03-01

233

Transcritical carbon dioxide small commercial cooling applications analysis  

Microsoft Academic Search

This paper presents a project to develop an R744 commercial single door bottle cooler that is cost competitive and matches the performance of typical cost optimised R404A and R134a systems. Compressors with different displacement and efficiency values are evaluated for refrigerating systems with fin and tube and steel wire-on-tube gas coolers. Capillary tubes are tested. A methodology to properly sizing

Luca Cecchinato; Marco Corradi

2011-01-01

234

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

235

Thermal conductivity of a wide range of alternative refrigerants measured with an improved guarded hot-plate apparatus  

Microsoft Academic Search

The thermal conductivity of the refrigerants R22, R123, R134a, R142b, R143a, and R152a has been determined as a function of temperature in the range from 300 to 460 K. Measurements were carried out at atmospheric pressure with an improved guarded hot-plate apparatus. The width of the instrument's gas layer and the temperature difference across the metering section were varied to

U. Hammerschmidt

1995-01-01

236

Gas chromatographic measurements of activity coefficients at infinite dilution for refrigerants with a polyol ester oil as a stationary phase  

Microsoft Academic Search

Activity coefficients at infinite dilution have been measured by gas chromatography for 14 refrigerants (R12, R22, R32, R124, R125, R134a, R142b, R143a, RE170, R236ea, R290, R600, R600a, and R236fa) as solutes, using a polyol ester oil (POE), EMKARATE by ICI, as a stationary phase (solvent). Instrumental analysis (NMR, IR) showed that the main components of the oil are pentaerithritol esters

Roman Stryjek; Sergio Bobbo; Roberto Camporese; Claudio Zilio

1999-01-01

237

Two-phase pressure drop of refrigerants during flow boiling in small channels: an experimental investigation and correlation development  

Microsoft Academic Search

Two-phase flow pressure drop measurements were made during a phase-change heat transfer process with three refrigerants (R-134a, R-12, and R-113) at six different pressures ranging from 138 to 856 kPa, and in two sizes of round tubes (2.46 and 2.92 mm inside diameters) and one rectangular channel (4.06 × 1.7 mm). The data were compared with those from large tubes

T. N Tran; M.-C Chyu; M. W Wambsganss; D. M France

2000-01-01

238

Refrigerant pressure drop in chevron and bumpy style flat plate heat exchangers  

Microsoft Academic Search

Adiabatic pressure drop in chevron and two styles of bumpy plate heat exchangers were investigated for vertical upward flow with R134a. Qualities ranging from sub-cooled liquid to superheated vapor were investigated. Mass fluxes ranged from 16kg\\/m2s (for superheated vapor) to approximately 300kg\\/m2s (for sub-cooled liquid). The pressure drop experiments were conducted for 10°C and 20°C inlet temperatures. A two-phase pressure

E. W. Jassim; T. A. Newell; J. C. Chato

2006-01-01

239

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

240

Feed gas drier precooling in mixed refrigerant natural gas liquefaction processes  

Microsoft Academic Search

A process is described for the liquefaction of a natural gas feedstream using two closed cycle, multicomponent refrigerants wherein a high level refrigerant cools a low level refrigerant and the low level refrigerant cools and liquefies the natural gas feedstream which includes: cooling and liquefying a natural gas stream by heat exchange with a low level multicomponent refrigerant in a

Y. N. Liu; C. L. Newton

1988-01-01

241

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

242

Method and apparatus for passive refrigerant retrieval and storage  

SciTech Connect

This patent describes a method of retrieving and storing refrigerant from a cooling system being serviced of the type having a compressor for circulating a compressible refrigerant in a closed, pressurized system between a condenser and an evaporator to provide a cooling effect. It comprises: connecting one end of a refrigerant collector tube contained within a housing to the cooling system at the condenser outlet; connecting the interior of the housing to the compressor inlet; operating the cooling system compressor to pressurize refrigerant in the cooling system and pump the refrigerant into the collector tube; and discharging refrigerant from the collector tube into the housing interior through a metering valve where the refrigerant pressure is reduced and evaporates and cools the refrigerant remaining in the tube and the evaporated refrigerant is drawn into the compressor inlet whereby the refrigerant becomes trapped within the housing.

Squire, D.C.

1991-12-17

243

Large area impingement spray cooling from multiple normal and inclined spray nozzles  

NASA Astrophysics Data System (ADS)

An inclined spray chamber with four multiple nozzles to cool a 1 kW 6U electronic test card has been designed and tested in this study. The multiple inclined sprays can cover the same heated surface area as that with the multiple normal sprays but halve the volume of the spray chamber. The spray cooling system used R134a as a working fluid in a modified refrigeration cycle. It is observed that increasing mass flow rate and pressure drop across the nozzles improved the heat transfer coefficient with a maximum enhancement of 117 %, and reduced the maximum temperature difference at the heated surface from 13.8 to 8.4 °C in the inclined spray chamber with a heat flux of 5.25 W/cm2, while the heat transfer coefficient of the normal spray increased with a maximum enhancement of 215 % and the maximum temperature difference decreased from 10.8 to 5.4 °C under similar operating conditions. We conclude that the multiple inclined sprays could produce a higher heat transfer coefficient but with an increase in non-uniformity of the surface temperature compared with the multiple normal sprays.

Yan, Z. B.; Duan, F.; Wong, T. N.; Toh, K. C.; Choo, K. F.; Chan, P. K.; Chua, Y. S.; Lee, L. W.

2013-07-01

244

Saturated liquid viscosity correlations for alternative refrigerants  

SciTech Connect

This article presents dimensionless equations for the temperature dependence of the saturated liquid viscosity of R32, R123, R124, R125, R134a, R141b, and R152a valid over a temperature range of engineering interest. The correlation has the form {Phi}{sub D}{sup n}= A +BT{sub D} where {Phi}{sub D} is the dimensionless fluidity (1/{eta}{sub D}) and T{sub D} is a dimensionless temperature. n, A, and B are evaluated for each of the above refrigerants based on a least-squares fit to experimental data. This equation is found to provide an improved fit over those existing in the literature up to T{sub D} = 0.8.

Khan, S.; Srinivasan, K. [Indian Inst. of Science, Bangalore (India)

1996-03-01

245

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

246

Energy Efficiency and Environmental Impact Analyses of Supermarket Refrigeration Systems  

SciTech Connect

This paper presents energy and life cycle climate performance (LCCP) analyses of a variety of supermarket refrigeration systems to identify designs that exhibit low environmental impact and high energy efficiency. EnergyPlus was used to model refrigeration systems in a variety of climate zones across the United States. The refrigeration systems that were modeled include the traditional multiplex DX system, cascade systems with secondary loops and the transcritical CO2 system. Furthermore, a variety of refrigerants were investigated, including R-32, R-134a, R-404A, R-1234yf, R-717, and R-744. LCCP analysis was used to determine the direct and indirect carbon dioxide emissions resulting from the operation of the various refrigeration systems over their lifetimes. Our analysis revealed that high-efficiency supermarket refrigeration systems may result in up to 44% less energy consumption and 78% reduced carbon dioxide emissions compared to the baseline multiplex DX system. This is an encouraging result for legislators, policy makers and supermarket owners to select low emission, high-efficiency commercial refrigeration system designs for future retrofit and new projects.

Fricke, Brian A [ORNL; Bansal, Pradeep [ORNL; Zha, Shitong [Hillphoenix

2013-01-01

247

Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains a minimum of 118 citations and includes a subject term index and title list.)

NONE

1995-01-01

248

Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

NONE

1995-12-01

249

Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains a minimum of 107 citations and includes a subject term index and title list.)

Not Available

1994-02-01

250

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

251

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

252

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

253

System for cooling  

Microsoft Academic Search

A cooling system particularly suitable for use in the air conditioning of buildings is described. The system includes: (A) a cooling zone containing a conduit for cooling fluid, the conduit encountering the heat load, means in the conduit for propelling the fluid through the conduit, and cooling fluid in the conduit; (B) a refrigeration zone containing a closed refrigeration circuit

Wildfeuer

1981-01-01

254

Magnetic refrigeration: materials, design, and applications. January 1975-April 1989 (Citations from the INSPEC: Information Services for the Physics and Engineering Communities data base). Report for January 1975-April 1989  

SciTech Connect

This bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parisitic refrigerators, Ericsson refrigerators, and Stirling-cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains 103 citations fully indexed and including a title list.)

Not Available

1989-05-01

255

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

256

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

257

Revised Viscosities of Saturated Liquid Halocarbon Refrigerants from 273 to 353 K  

Microsoft Academic Search

This paper presents revised saturated liquid viscosities for 15 halocarbon refrigerants, that is, R11, R12, R22, R13B1, R152a, R113, R123, R123a, R143a, R114, R134a, R141b, R142b, R225ca, and R225cb, reported in our previous papers [1, 2], in which the vapor buoyancy correction for the sealed capillary viscometer was not applied. The maximum corrections amount to from 1.2% for R225cb to

A. Kumagai; C. Yokoyama

2000-01-01

258

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

259

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

260

Measurements of the thermal conductivity of refrigerants in the vapor phase  

SciTech Connect

Measurements of the thermal conductivity of refrigerants R124, R125, and R134a in the vapor phase are presented. The measurements, performed in a newly developed transient hot-wire instrument, cover a temperature range from 273 to 333 K, and a pressure range from about atmospheric up to below the saturation pressure. A finite-elements program developed allowed the reexamination of the major corrections employed in the analysis of the results. The uncertainty of the reported values is estimated to be better than {+-}1%. Comparisons with measurements of other investigators along the saturation line show a lack of reliable thermal conductivity data in the vapor phase for these compounds.

Assael, M.J.; Malamataris, N.; Karagiannidis, L. [Aristotle Univ., Thessaloniki (Greece). Faculty of Chemical Engineering

1997-03-01

261

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

262

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

263

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

264

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

265

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

266

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

267

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

268

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 ...

269

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

270

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

271

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

272

Surface tension for 1,1,1-trifluorethane (R-143a), 1,1,1,2-tetrafluoroethane (R-134a), 1,1-dichloro-2,2,3,3,3-pentafluoropropane (R-225ca), and 1,3-dichloro-1,2,2,3,3-pentafluoropropane (R-225cb)  

SciTech Connect

The surface tensions for 1,1,1-trifluoroethane (R-143a), 1,1,1,2-tetrafluoroethane (R-134a), 1,1-dichloro-2,2,3,3,3-pentafluoropropane (R-225ca), and 1,3-dichloro-1,2,2,3,3-pentafluoropropane (R-225cb) have been measured by the differential capillary rise method. The results were obtained in the temperature range between 273 K and 343 K. The experimental uncertainties of temperature and surface tension are estimated to be within {+-}20 mK and {+-}0.15 mN/m, respectively. A correlation for the surface tension as a function of temperature is presented.

Higashi, Yukihiro; Shibata, Takahide [Iwaki Meisei Univ., Fukushima (Japan). Dept. of Mechanical Engineering; Okada, Masaaki [Tsukuba Coll. of Technology, Ibaraki (Japan). Dept. of Mechanical Engineering

1997-05-01

273

Modeling of secondary loop refrigeration systems in supermarket applications  

Microsoft Academic Search

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

William Travis Horton

2002-01-01

274

Combined marine refrigerating and air conditioning system using thermal storage  

Microsoft Academic Search

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

Alston

1993-01-01

275

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

276

A New Surface Tension Equation for Refrigerants  

NASA Astrophysics Data System (ADS)

This study presents a new formula for the surface tension prediction of refrigerants. As a first step, an analysis of the available experimental surface tension data for refrigerants was performed. The experimental data were collected, after a careful literature survey, for the following pure fluids: R11, R12, R13, R13B1, R14, R21, R22, R23, R32, R113, R114, R115, R123, R124, R125, R134, R134a, R141b, R143a, R152a, R218, R227ea, R236ea, R236fa, R245ca, R245fa, R365mfc, and R1234yf. Then, the experimental data were regressed with the most reliable semi-empirical correlating methods based on the corresponding-states theory existing in the literature. As a final step, to minimize the deviation between the predicted data and the experimental data and to find the optimal equation for experimental data regression, a (? + ?)-evolution strategy was adopted. After a careful statistical analysis of the results, a new formula based on the corresponding-states principle with improved representation of the experimental results was found and proposed.

Di Nicola, Giovanni; Di Nicola, Cristiano; Moglie, Matteo

2011-05-01

277

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

278

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

279

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

280

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

281

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

282

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

283

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

284

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

285

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

286

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

287

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

288

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

289

Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC: Information Services for the Physics and Engineering Communities datab base). Published Search  

SciTech Connect

The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains a minimum of 87 citations and includes a subject term index and title list.)

Not Available

1992-10-01

290

Magnetic refrigeration: Materials, design, and applications. (Latest citations from the INSPEC: Information services for the Physics and Engineering Communities database). Published Search  

SciTech Connect

The bibliography contains citations concerning cryogenics using magnetic refrigerants. Refrigerant properties, magnetic materials, and thermal characteristics are discussed. Magnetic refrigerators are used for helium liquefaction, cooling superconductors, and superfluid helium production. Carnot-cycle refrigerators, reciprocating refrigerators, parasitic refrigerators, Ericsson refrigerators, and Stirling cycle refrigerators are among the types of magnetic refrigerators evaluated. (Contains a minimum of 94 citations and includes a subject term index and title list.)

NONE

1993-08-01

291

Barocaloric effect and the pressure induced solid state refrigerator  

SciTech Connect

The current refrigerators are based on the heating and cooling of fluids under external pressure variation. The great inconvenience of this refrigeration technology is the damage caused to the environment by the refrigerant fluids. In this paper, we discuss the magnetic barocaloric effect, i.e., the heating or cooling of magnetic materials under pressure variation and its application in the construction of refrigerators using solid magnetic compounds as refrigerant materials and pressure as the external agent. The discussion presented in this paper points out that such a pressure induced solid state refrigerator can be very interesting because it is not harmful to the environment and can exhibit a good performance.

Oliveira, N. A. de [Instituto de Fisica Armando Dias Tavares Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier 524, Rio de Janeiro, 20550-013, RJ (Brazil)

2011-03-01

292

Feed gas drier precooling in mixed refrigerant natural gas liquefaction processes  

SciTech Connect

A process is described for the liquefaction of a natural gas feedstream using two closed cycle, multicomponent refrigerants wherein a high level refrigerant cools a low level refrigerant and the low level refrigerant cools and liquefies the natural gas feedstream which includes: cooling and liquefying a natural gas stream by heat exchange with a low level multicomponent refrigerant in a first closed refrigeration cycle, which refrigerant is rewarmed during the heat exchange, compressing the rewarmed low level refrigerant to an elevated pressure and aftercooling it against an external cooling fluid, further cooling the low level refrigerant by multiple stage heat exchange against a high level multicomponent refrigerant in a second closed refrigeration cycle, which high level refrigerant is rewarmed during the heat exchange, compressing the rewarmed high level refrigerant to an elevated pressure and aftercooling it against an external cooling fluid to partially liquefy the refrigerant, phase separating the high level refrigerant into a vapor phase refrigerant stream and a liquid phase refrigerant stream.

Liu, Y.N.; Newton, C.L.

1988-07-05

293

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

294

Viscosity of saturated liquid fluorocarbon refrigerants from 273 to 353 K  

NASA Astrophysics Data System (ADS)

Viscosity measurements were carried out on saturated liquid fluorocarbon refrigerants using an improved capillary viscometer for 11 kinds of fluorocarbon refrigerants; CCl3F (R11), CCl2F2 (R12), CHClF2 (R22), CBrF3 (R13B1), CH3CHF2 (R152a), CCl2FCClF2 (R113), CHCl2CF3 (R123), CHClFCClF2 (R123a), CH3CF3 (R143a), CClF2CCl2F2 (R114), and CH2FCF3 (R134a), in the temperature range from 273 to 353 K. An equation is given to represent the viscosity as a function of temperature.

Kumagai, A.; Takahashi, S.

1991-01-01

295

Viscosity of saturated liquid fluorocarbon refrigerants from 273 to 353 K  

Microsoft Academic Search

Viscosity measurements were carried out on saturated liquid fluorocarbon refrigerants using an improved capillary viscometer for 11 kinds of fluorocarbon refrigerants; CCl3F (R11), CCl2F2 (R12), CHClF2 (R22), CBrF3 (R13B1), CH3CHF2 (R152a), CCl2FCClF2 (R113), CHCl2CF3 (R123), CHClFCClF2 (R123a), CH3CF3 (R143a), CClF2CCl2F2 (R114), and CH2FCF3 (R134a), in the temperature range from 273 to 353 K. An equation is given to represent the

A. Kumagai; S. Takahashi

1991-01-01

296

Prediction of refrigerant void fraction in horizontal tubes using probabilistic flow regime maps  

SciTech Connect

A state of the art review of two-phase void fraction models in smooth horizontal tubes is provided and a probabilistic two-phase flow regime map void fraction model is developed for refrigerants under condensation, adiabatic, and evaporation conditions in smooth, horizontal tubes. Time fraction information from a generalized probabilistic two-phase flow map is used to provide a physically based weighting of void fraction models for different flow regimes. The present model and void fraction models in the literature are compared to data from multiple sources including R11, R12, R134a, R22, R410A refrigerants, 4.26-9.58 mm diameter tubes, mass fluxes from 70 to 900 kg/m{sup 2} s, and a full quality range. The present model has a mean absolute deviation of 3.5% when compared to the collected database. (author)

Jassim, E.W.; Newell, T.A.; Chato, J.C. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)

2008-04-15

297

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

298

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

299

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

300

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

301

Test results on a thermosyphon concept to high-power cool desktop computers and servers  

Microsoft Academic Search

This paper reports measured thermal performance of two prototype thermo-syphon devices designed to cool desktop computers and servers. The prototype was designed to reject 100 W with 35 K CPU-to-air temperature difference using an 80 mm 3350 rpm fan for air flow. One prototype is aluminum and uses R-134A, while the other is copper and uses water. The working fluid

R. L. Webb; Shinobu Yamauchi; Showa Denko

2002-01-01

302

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

303

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

304

Feasibility Study of an Automotive Thermoacoustic Refrigerator  

Microsoft Academic Search

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

Luke Zoontjens; Carl Howard; Anthony Zander; Ben Cazzolato

2005-01-01

305

The refrigerated gas and vapor turbine cycle  

Microsoft Academic Search

Gas turbine engineers have long known that a reduction in turbine air intake temperature results in an increase in net power output. This fact has initiated the investigation of various means to cool intake air without expending more power to do so than the projected gain itself. The author plot refrigerated and non-refrigerated cases both on the same set of

J. H. Anderson; F. M. Laucks

1987-01-01

306

Theoretical optimization of a regenerated air refrigerator  

Microsoft Academic Search

The performance analysis and optimization of a regenerated air refrigerator is carried out by taking the cooling load density, i.e. the ratio of cooling load to the maximum specific volume in the cycle, as the optimization objective using finite-time thermodynamics or entropy generation minimization in this paper. Analytical relationships between cooling load density and pressure ratio, as well as between

Shengbing Zhou; Lingen Chen; Fengrui Sun; Chih Wu

2003-01-01

307

Review of solar sorption refrigeration technologies: Development and applications  

Microsoft Academic Search

In this paper, a review of the research state of art of the solar sorption (absorption and adsorption) refrigeration technologies is presented. After an introduction of basic principles, the development history and recent progress in solar sorption refrigeration technologies are reported. The application areas of these technologies are categorized by cooling temperature demand. It shows that solar-powered sorption refrigeration technologies

Y. Fan; L. Luo; B. Souyri

2007-01-01

308

Refrigeration for Cryogenic Sensors and Electronic Systems.  

National Technical Information Service (NTIS)

The purpose of the meeting was to discuss progress in the development of refrigeration systems which have been specialized for use with cryogenic sensors and electronic systems. The meeting focused primarily on the temperature range below 20 K and cooling...

D. B. Sullivan J. E. Zimmerman S. E. McCarthy

1981-01-01

309

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

310

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

311

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

312

Dilution refrigerator for muon spin relaxation experiments  

SciTech Connect

The design, construction, and operational characteristics of a continuous THe--UHe dilution refrigerator specifically built for use in muon spin relaxation ( SR) measurements at LAMPF are described in this paper. The refrigerator is unique in that it makes an angle of 30 with respect to horizontal: a requirement imposed by the previously existing physical constraints of the SR spectrometer. Additionally, the refrigerator and associated gas handling units are portable so as to facilitate ease of movement into and out of the muon beam. Typical parameters describing refrigerator performance are 60-mK base temperature with 22- W cooling capacity at 100 mK.

Cooke, D.W.; Hoffer, J.K.; Maez, M.; Steyert, W.A.; Heffner, R.H.

1986-03-01

313

Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage.  

PubMed

Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted. PMID:11288304

Levine, C; Younglove, T; Barth, M

2000-10-01

314

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

315

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

316

Two-phase pressure drop of refrigerants during flow boiling in small channels : an experimental investigation and correlation development.  

SciTech Connect

Two-phase flow pressure drop measurements were made during a phase-change heat transfer process with three refrigerants (R-134a, R-12, and R-113) at six different pressures ranging from 138 kPa to 856 kPa, and in two sizes of round tubes (2.46 mm and 2.92 mm inside diameters) and one rectangular channel (4.06 x 1.7 mm). State-of-the-art large-tube correlations failed to satisfactorily predict the experimental data. The data were used to develop a new correlation for two-phase pressure drop during flow boiling in small channels. The correlation was then tested against the experimental data for the three refrigerants; the error was {+-}20%.

Chyu, M.-C.; France, D. M.; Tran, T. N.; Wambsganss, M. W.

1999-01-19

317

Combination cooler and freezer for refrigerating containers and food in outer space  

SciTech Connect

A refrigeration apparatus for cooling containers and food in the microgravity conditions of outer space is described comprising: (a) a housing defining a refrigeration compartment for supporting the containers in a container storage area and food in a refrigerated food storage area, and freezer compartment; (b) cold plate means within the refrigeration compartment for cooling the containers and food by conduction; (c) thermoelectric refrigeration means for maintaining the cold plates at temperatures which cool the contents of the refrigeration compartment, and the freezer compartment.

Rudick, A.G.

1988-04-19

318

Combined marine refrigerating and air conditioning system using thermal storage  

SciTech Connect

A refrigerating and air conditioning system is described for a marine vessel which comprises: (a) a single compressor means to create a pressure differential in the refrigerant gas, and (b) a water cooled condenser to cause the pressurized refrigerant gas to liquify, and (c) a receiver to store liquidized refrigerant gas, and (d) a heat transfer means to transfer heat from the liquified refrigerant at a higher pressure to the gaseous refrigerant at a lower pressure, and (e) a means to remove moisture and particulate matter from the circulating refrigerant, and (f) a liquid refrigerant distribution means to cause liquid refrigerant to flow in a controlled manner through any one of a plurality of circuits into expansion valves supplying a metered flow of refrigerant to refrigerating and air conditioning evaporator coils with such, (g) refrigerating evaporator coils enclosed in a sealed container and surrounded by a liquid storing medium from which heat can be extracted causing the liquid to solidify and to which heat can be added causing the solidified medium to liquify with little rise in temperature and, such (h) air conditioning evaporator coils positioned so that air pressurized by a blower shall flow over them enabling heat to be removed from the passing air into the evaporating refrigerant, and (i) a means to remove liquid refrigerant from gaseous refrigerant flowing from the evaporators to the compressor.

Alston, G.A.

1993-08-24

319

Gas chromatographic measurements of activity coefficients at infinite dilution for refrigerants with a polyol ester oil as a stationary phase  

SciTech Connect

Activity coefficients at infinite dilution have been measured by gas chromatography for 14 refrigerants (R12, R22, R32, R124, R125, R134a, R142b, R143a, RE170, R236ea, R290, R600, R600a, and R236fa) as solutes, using a polyol ester oil (POE), EMKARATE by ICI, as a stationary phase (solvent). Instrumental analysis (NMR, IR) showed that the main components of the oil are pentaerithritol esters of carboxylic acids, and electrospray ionization spectrometry revealed an average molecular mass of the POE of 618 g/mol. The measurements were performed within a temperature range of 244 K to 313 K, but a specific temperature range for each refrigerant was adopted depending on its retention data. The experimental findings are well-represented by the equation: ln {gamma}{sub i}{sup {infinity}} = a{sub i} {minus} b{sub i}/T. Some refrigerants, i.e., R22, R124, R125, R236ea, and R236fa, show quite a considerable positive temperature dependence of their activity coefficients at infinite dilution, which can be attributed to hydrogen bonding with the POE, unlike other refrigerants that show a small, either positive or negative temperature dependence. To the authors` knowledge, there are no data in the literature on activity coefficients at infinite dilution for refrigerant and oil (lubricant) systems, and details on the solubility of refrigerants in oils are also extremely scarce.

Stryjek, R. [Polish Academy of Sciences, Warsaw (Poland). Inst. of Physical Chemistry; Bobbo, S.; Camporese, R. [National Research Council, Padova (Italy). Inst. of Refrigeration; Zilio, C. [Univ. di Padova (Italy). Dept. di Fisica Tecnica

1999-05-01

320

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

321

Photonic and electronic cooling  

Microsoft Academic Search

Thermal management, which is usually regarded as the domain of mechanical engineering, actually offers exciting opportunities for photonics and electronics. This talk will describe research at Los Alamos National Laboratory and at the University of New Mexico on optical refrigeration and on thin-film electrocaloric heat engines. In optical refrigeration, the goal is to cool solids, typically rare-earth doped glasses and

Richard I. Epstein

2009-01-01

322

Apparatus of the Vapor-pressure Measurements for Natural Refrigerants  

NASA Astrophysics Data System (ADS)

An apparatus for measuring the vapor-pressures was newly designed and constructed in order to make the basic thermodynamic properties for environmentally acceptable refrigerants clear. The temperature of sample fluid was measured with 100? platinum resistance thermometer calibrated against ITS-90 using a 25? standard platinum resistance thermometer. With respect to the pressure measurement, two kinds of presure transducer were adopted. One is a diaphragm semi-conductor strain pressure transducer with the uncertainty of ±0.09%. This pressure transducer was calibrated against quartz crystal pressure transducer with the uncertainty of ±0.01% after every series of experiments. Another is a quartz crystal pressure transducer with the uncertainty of ±0.01%. A quartz crystal pressure transducer was calibrated against the dead weight pressure gauge and barometer. The vapor-pressures for R-32, R-134a, R-290 (propane), R-600a (iso-butane) and n-pentane were measured in the temperature range between273.15 and 323.15K. As the results of vapor-pressure measurements, the reliability of the experimental apparatus as well as the reproducibility of the experimental data were confirmed. In addition, coefficients of Antoine vapor pressure equation were determined from the experimental data. Normal boiling points for environmentally acceptable refrigerants were also determined with high accuracy.

Higuchi, Satoru; Higashi, Yukihiro

323

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

324

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

325

Sealed tube comparisons of the compatibility of desiccants with refrigerants and lubricants  

NASA Astrophysics Data System (ADS)

Continuing environmental concerns mandate replacement of CFC's with alternate refrigeration fluids. At this time relatively little testing has been reported in the literature for compatibility of desiccants in these new working fluids. Work has begun, and some results are reported, on a project that will determine the compatibility of virtually all of the currently used desiccant types--both bead and molded core--with thirteen refrigerant/lubricant combinations. The desiccants are tested by exposure to refrigerant and lubricant in sealed, glass tubes in accordance with ASHRAE/ANSI Standard 97-1989. After aging the lubricants are evaluated for change in color and acid formation. The refrigerants are analyzed for charges by gas chromatography and halide ion formation using ion chromatography. The desiccants are evaluated for changes in crush strength and for retention of acids and halide ions. Metal catalysts, also present in the sealed tubes, are visually examined for corrosion, copper plating, and appearance change. Results are reported for 4 A and 3 A molecular sieve desiccants aged in R-12, R-134a, and R-32.

Field, J. E.

326

Sealed tube comparisons of the compatibility of desiccants with refrigerants and lubricants  

SciTech Connect

Continuing environmental concerns mandate replacement of CFC`s with alternate refrigeration fluids. At this time relatively little testing has been reported in the literature for compatibility of desiccants in these new working fluids. Work has begun, and some results are reported, on a project that will determine the compatibility of virtually all of the currently used desiccant types -- both bead and molded core, with thirteen refrigerant/lubricant combinations. The desiccants are tested by exposure to refrigerant and lubricant in sealed, glass tubes in accordance with ASHRAE/ANSI Standard 97-1989. After aging the lubricants are evaluated for change in color and acid formation. The refrigerants are analyzed for charges by gas chromatography and halide ion formation using ion chromatography. The desiccants are evaluated for changes in crush strength, and for retention of acids and halide ions. Metal catalysts, also present in the sealed tubes, are visually examined for corrosion, copper plating, and appearance change. Results are reported for 4{Angstrom} and 3{Angstrom} molecular sieve desiccants aged in R-12, R-134a and R-32.

Field, J.E. [Spauschus Associates, Inc., Stockbridge, GA (United States)

1994-04-01

327

A survey of current worldwide research on the thermophysical properties of alternative refrigerants  

NASA Astrophysics Data System (ADS)

The survey represents an exhaustive compilation of the research activities throughout the world concerned with either measurements or correlations of the thermophysical properties of alternative refrigerants. The properties covered include thermodynamic, transport, phase equilibria, and other properties such as dielectric constant and refractive index. The survey included a wide range of fluids (including R23, R32, R125, R143a, R22, R134a, R152a, R134, R124, R142b, R123, R123a, R141b) along with mixtures containing at least one of these fluids. Summary information is presented in tabular form about each research activity; the survey does not present raw data or correlating equations.

McLinden, M. O.; Haynes, W. M.; Watson, J. T. R.; Watanabe, K.

1991-06-01

328

Development of a prototype optical refrigerator  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have carried out a range of tasks directed toward the construction and testing of a proof-of-principle optical refrigerator prototype. They procured and tested new cooling elements that are at the heart of an optical refrigerator. The cooling element absorbs pump radiation and then fluoresces with nearly unity quantum efficiency. They constructed and tested a cooling chamber with low thermal emissivity walls that reduces the parasitic heating.

Epstein, R.I.; Edwards, B.C.; Sigel, G.H.

1998-01-01

329

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, C.M.

1981-07-29

330

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

331

Counterflow absorber for an absorption refrigeration system  

DOEpatents

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

Reimann, Robert C. (Lafayette, NY)

1984-01-01

332

Magnetic refrigeration: the promise and the problems  

SciTech Connect

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

Barclay, J.A.

1984-01-01

333

Cycle design for the ISABELLE helium refrigerator  

SciTech Connect

The superconducting magnets for the ISABELLE storage ring/accelerator are designed to be operated at 3.8/sup 0/K using a forced-flow supercritical helium cooling system. The ISABELLE refrigerator has been designed subject to these special requirements. The design output is 13.65 KW of refrigeration below 4.2/sup 0/K (for cooling the magnet and distribution system), 55 KW at 55/sup 0/K (to cool heat shields for the whole system) and 100 g/s of liquefaction (for magnet power leads cooling). The system incorporates a subcooler section that produces liquid helium at 5.3 atm and 2.6 K and circulates it through the loads, and a Claude-type main refrigerator section. The main refrigerator section has five stages of cooling, with four of them below liquid nitrogen temperature. Liquid nitrogen precooling is not used. With 60% isothermal compressors the efficiency of the refrigerator system will be about 26% of Carnot.

Brown, D.P.; Schlafke, A.P.; Wu, K.C.; Moore, R.W.

1981-01-01

334

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

SciTech Connect

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

None

2010-10-01

335

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

336

Dipole moments of seven partially halogenated ethane refrigerants  

SciTech Connect

Dielectric constant measurements have been performed on seven partially halogenated ethanes, currently being considered as alternative refrigerants, in the gaseous state over the range 305-415 K in order to determine their dipole moments. Argon was also studied to test the apparatus. Five of the refrigerants have temperature-independent moments: R125 (CF{sub 3}CHF{sub 2}), {mu} = 1.563 {plus minus} 0.005 D; R134a (CF{sub 3}CH{sub 2}F), {mu} = 2.058 {plus minus} 0.010 D; R143a (CF{sub 3}CH{sub 3}), {mu} = 2.340 {plus minus} 0.010 D; R152a (CHF{sub 2}CH{sub 3}), {mu} = 2.262 {plus minus} 0.008 D; and R124 (CF{sub 3}CHClF), {mu} = 1.469 {plus minus} 0.012 D. Two refrigerants have conformer-dependent moments, making their time-averaged moments temperature dependent: R134 (CHF{sub 2}CHF{sub 2}), with a moment ranging from 0.991 {plus minus} 0.004 D at 309 K to 1.250 {plus minus} 0.004 D at 413 K; and R143 (CHF{sub 2}CH{sub 2}F), where the moment ranges from 1.680 {plus minus} 0.001 D at 309 K to 1.745 {plus minus} 0.001 D at 410 K. Accurate estimation of a molecule's temperature-dependent dipole moment requires an independent determination of its polarizability; this determination has been made from index of refraction measurements. Where possible, the present results are compared with earlier determinations of dipole moments. In all but one instance, the agreement is good.

Meyer, C.W.; Morrison, G. (National Inst. of Standards and Technology, Gaithersburg, MD (United States))

1991-05-02

337

THE EFFECTS OF DIFFERENT COOLING TECHNIQUES ON QUALITY PARAMETERS OF HERRING IN RELATION TO MALAYSIAN FISHERIES AND DESIGN OF REFRIGERATION SYSTEM SUITABLE FOR MALAYSIAN VESSELS  

Microsoft Academic Search

A comparison of three different cooling systems was carried out with the environmental temperature at 2°C and 25°C using herring (Clupea harengus) as raw material. Ungutted herring was stored in flake ice, CSW, and liquid ice using un- insulated polyethylene boxes for a period of 10 days. During storage protein, fat, salt, total volatile nitrogen compounds (TVB-N) and total plate

Razak Bin Hassan

338

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

339

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

340

Method of reducing chlorofluorocarbon refrigerant emissons to the atmosphere  

DOEpatents

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

DeVault, Robert C. (Knoxville, TN); Fairchild, Phillip D. (Clinton, TN); Biermann, Wendell J. (Fayetteville, NY)

1990-01-01

341

Development of a solar-powered passive ejector cooling system  

Microsoft Academic Search

This paper describes the development of an ejector refrigeration system that is powered by solar thermal energy. The cooling system contains no active parts and is therefore deemed passive. Water is used as the refrigerant though other natural refrigerants could be used for lower temperature operation. A prototype system was built with a nominal cooling capacity of 7 kW. This

V. M Nguyen; S. B Riffat; P. S Doherty

2001-01-01

342

Performance of a gamma-ray and x-ray spectrometer utilizing germanium and Si(Li) detectors cooled by a closed-cycle cryogenic mechanical refrigerator  

SciTech Connect

A mechanically cooled spectrometer has been constructed and tested separately with Si(Li) planar, high-purity germanium (HPGe) planar, and HPGe coaxial detectors. For each of these types of semiconductor detectors, this spectrometer has attained the lowest noise and best resolution at 5.9 keV, 122 keV, or 1.33 MeV of any closed-cycle mechanically cooled spectrometer which has been reported on in the literature. Resolutions at 5.9 keV were 175 eV FWHM with a 4 mm diameter Si(Li) detector and 202 eV with a 16 mm HPGe planar detector. With a 10% relative efficiency HPGe coaxial detector, resolutions of 816 eV at 122 keV and 1.70 keV at 1.33 MeV were obtained.

Stone, R.E.; Barkley, V.A.; Fleming, J.A.

1986-02-01

343

Performance analysis and optimization of a single barrier solid-state thermionic refrigerator with external heat transfer  

Microsoft Academic Search

A model of a single barrier solid-state thermionic refrigerator with external heat transfer is established in this paper. The performance of the refrigerator is analyzed and optimized by using the combination of finite time thermodynamics and non-equilibrium thermodynamics. The general expressions for cooling load and coefficient of performance (COP) of the refrigerator are derived. The optimum regions of cooling load

ZE-MIN DING; LIN-GEN CHEN; FENG-RUI SUN

2012-01-01

344

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

345

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

346

Development of the Los Alamos solid-state optical refrigerator  

Microsoft Academic Search

Laser-induced cooling of a solid by net anti-Stokes fluorescence, first experimentally demonstrated in 1995, can be the basis of a new type of cryocooler, an optical refrigerator. This article describes the physics and design issues of a practical optical refrigerator for operation at 77 K. In particular, the Los Alamos Solid-State Optical Refrigerator (LASSOR) which we are developing would have

Bradley C. Edwards; Melvin I. Buchwald; Richard I. Epstein

1998-01-01

347

IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems  

SciTech Connect

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

Baxter, VAN

2003-05-19

348

A Nanosize Quantum-Dot Photoelectric Refrigerator  

NASA Astrophysics Data System (ADS)

We investigate the thermodynamic performance of a nanosized photoelectric refrigerator consisting of two single energy levels embedded between two reservoirs at different temperatures. Based on the quantum master equation, expressions for the cooling power and coefficient of performance (COP) of the refrigerator are derived. The characteristic curves between the cooling power and COP are plotted. Moreover, the optimal performance parameters are analyzed by the numerical calculation and graphic method. The influence of the nonradiative processes on the performance characteristics and optimal performance parameters are discussed in detail.

Li, Cong; Zhang, Yan-Chao; He, Ji-Zhou

2013-10-01

349

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

350

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

351

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

352

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

353

HTS microwave devices and subsystems with pulse tube refrigerators  

Microsoft Academic Search

Two new types of pulse tube refrigerators with optimized cooling power of 6 W at 77 K have been designed and fabricated. Experiments show that vibration of the pulse tube refrigerators is at least an order of magnitude smaller than that of Stirling coolers. Two microwave devices, a HTS cavity and a HTS miniature lumped band-stop filter, were integrated with

Yusheng He; Yuan Zhou; Jingtao Liang; Hong Li; Luwei Yang; Wenxiu Zhu; Jinghui Cai; Aisheng He; Zhonglin Gong; Peiheng Wu; Yijun Feng; T. W. Button; P. A. Smith; M. J. Lancaster; F. Wellhofer; C. E. Gough

1999-01-01

354

Magnetically suspended Stirling cryogenic space refrigerator Status report  

Microsoft Academic Search

At the 1979 Cryogenic Engineering Conference, attention was given to conceptual designs of spaceborne cryogenic refrigeration systems which can provide long-term, unattended operation. Since that time, efforts have continued to translate one of those concepts into an engineering model. The present investigation is concerned with a refrigerator which was designed to generate 5 W of cooling power at a temperature

A. Daniels; M. Gasser; A. Sherman

1982-01-01

355

Study of fractionation of refrigerant blends in contact with lubricants and measurement of the solubility, density, and viscosity  

SciTech Connect

The fractionation of two refrigerant blends was studied using the gas equilibrium method. The amount of fractionation was measured by maintaining a constant composition of the refrigerant gas vapor over the lubricant, which was equal in composition to the liquid refrigerant gas blend introduced into the viscometer. Specifically, the concentration of the dissolved refrigerant gas in the lubricant ranges from 0.6% to 78% by weight in the specified temperature range of {minus}25 C to 125 C and within the highest test pressure of 500 psia (3.45 MPa). The polyolester chosen for this study was a 32 ISO VG complex branched acid pentaerythritol product. Smoothed graphical data presented were obtained from individual isothermal measurements. These individual isothermal measurement temperatures detail the composition of the equilibrium gas fractionation of R-32 and R-134a in the lubricant, mixed vapor pressure, concentration of the total mixed blend as percent by weight in the lubricant and viscosity in centipoise (cP) and centistokes (cSt). The raw data are presented in a smoothed graphical form based on a fixed vapor composition.

Cavestri, R.C.; Falconi, E.A.

1999-07-01

356

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.

357

The Carnot type magnetic refrigeration below 4.2 K - Computer simulation  

Microsoft Academic Search

Cooling devices based on a utilization of the Carnot type magnetic refrigeration cycle are usually selected for the temperature range from 20 K to 1.8 K. However, the refrigeration power in the case of such devices is frequently limited by the heat transfer coefficient between the heat source and the magnetic working substance. Thus, in a magnetic refrigerator studied by

T. Hashimoto; T. Numazawa; T. Maro

1984-01-01

358

Laser cooling of solids  

Microsoft Academic Search

Laser cooling in optical solids can lead to the realization of all-solid state cryocoolers. We present new results on Yb- and Tm-doped glasses and crystals and describe progress toward achieving net cooling in GaAs heterostructures. Solid-state laser cooling (optical refrigeration) is based on the principle of anti-Stokes fluorescence where laser photons with energy less than the mean fluorescence energy are

M. Sheik-Bahae; R. I. Epstein

2009-01-01

359

Results on the characterization of gas hydrate formation in a direct contact heat pump cool storage system  

Microsoft Academic Search

This report describes an investigation of a latent cool storage system which employs a refrigerant gas hydrate as the storage medium. A refrigerant gas hydrate is a compound consisting of a refrigerant gas molecule contained within a crystalline water molecule cage. In this system, the storage component is incorporated directly into the refrigeration cycle, replacing the conventional evaporator. The refrigerant

M. P. Ternes

1985-01-01

360

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

361

Ventilation Cooling: An Old Solution to New Problems. Part 1: The Economics.  

ERIC Educational Resources Information Center

|This first article in a series about cooling classrooms by ventilation explains that energy consumption for one day of refrigeration cooling is equal to energy use for 35 days of ventilation cooling. Schools using only refrigeration cooling are passing up energy savings that could be provided by ventilation cooling. (Author/MLF)|

DiMercurio, C.

1981-01-01

362

Experimental study of a three-adsorber sorption refrigerator for utilization of renewable sources of energy  

NASA Astrophysics Data System (ADS)

A three-adsorber refrigerator has been created and experimentally tested, in which use is made of a composite sorbent consisting of activated carbon fiber and alkali salts. This sorbent has a high capacity of storage of refrigeration characteristic of chemical coolers and a high sorption rate characteristic of adsorption refrigerators. The sorbent structure makes it possible to effect a convective intrapore process of cooling of the sorbent through intense two-phase heat transfer. A three-adsorber refrigerator has a higher refrigeration efficiency and smaller mass and overall dimensions than a traditional two-stage four-adsorber refrigerator.

Tsitovich, A. P.

2013-03-01

363

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

364

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

365

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

366

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

367

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

368

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

369

A closed-cycle dilution refrigerator for space applications  

NASA Astrophysics Data System (ADS)

We discuss the development of a gravity-insensitive dilution refrigerator adapted from the open-cycle refrigerator used for the Planck mission. Since the 3He and 4He components are circulated (the 4He by a fountain-effect pump operating at about 2 K, the 3He by a compressor at room temperature) rather than ejected into space, the lifetime of a closed-cycle refrigerator is not limited by the quantity of 3He and 4He available. In this work, we concentrate on the design and performance of the cold end (counterflow heat exchanger and mixing chamber) of the refrigerator. We discuss the sizing of the heat exchanger and present cooling power measurements. We detail the working of the fountain pump. We also briefly touch upon some practical issues including the choice of a 3He compressor and the pre-cooling requirements for the dilution refrigerator.

Chaudhry, Gunaranjan; Volpe, Angela; Camus, Philippe; Triqueneaux, Sébastien; Vermeulen, Gerard

2012-10-01

370

Hydronic rooftop cooling systems  

DOEpatents

A roof top cooling unit has an evaporative cooling section that includes at least one evaporative module that pre-cools ventilation air and water; a condenser; a water reservoir and pump that captures and re-circulates water within the evaporative modules; a fan that exhausts air from the building and the evaporative modules and systems that refill and drain the water reservoir. The cooling unit also has a refrigerant section that includes a compressor, an expansion device, evaporator and condenser heat exchangers, and connecting refrigerant piping. Supply air components include a blower, an air filter, a cooling and/or heating coil to condition air for supply to the building, and optional dampers that, in designs that supply less than 100% outdoor air to the building, control the mixture of return and ventilation air.

Bourne, Richard C. (Davis, CA); Lee, Brian Eric (Monterey, CA); Berman, Mark J. (Davis, CA)

2008-01-29

371

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

372

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

373

Magnetically suspended Stirling cryogenic space refrigerator Status report  

NASA Astrophysics Data System (ADS)

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

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

374

Novel materials for laser refrigeration  

SciTech Connect

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

Hehlen, Markus P [Los Alamos National Laboratory

2009-01-01

375

Ecological optimization criterion for an irreversible three-heat-source refrigerator  

Microsoft Academic Search

On the basis of a new irreversible three-heat-source refrigerator model, an ecological optimization criterion is proposed for the best mode of operation of the refrigerators, which consists of maximizing a function representing the best compromise between the cooling rate and entropy production rate. We investigate the ecological optimization performance and derive the optimal cooling rate, coefficient of performance and entropy

Zijun Yan; Guoxing Lin

2000-01-01

376

Application of waste heat powered absorption refrigeration system to the LNG recovery process  

Microsoft Academic Search

The recovery process of the liquefied natural gas requires low temperature cooling, which is typically provided by the vapor compression refrigeration systems. The usage of an absorption refrigeration system powered by waste heat from the electric power generating gas turbine could provide the necessary cooling at reduced overall energy consumption. In this study, a potential replacement of propane chillers with

Paul Kalinowski; Yunho Hwang; Reinhard Radermacher; Saleh Al Hashimi; Peter Rodgers

2009-01-01

377

Refrigeration system for W7-X  

NASA Astrophysics Data System (ADS)

The refrigeration system for the W7-X superconducting magnet and the divertor cryo-vacuum pumps is presented. In total, five main helium cooling circuits have to be supplied by the refrigerator—four for the magnet including auxiliary equipment like support structure, thermal shield and current leads, and one for the cryo-pumps. For the shields of the latter, an additional LN2—cooling circuit is required. The lowest operating temperature is 3.3 K. It will be provided by evacuating a sub-cooler bath using a cold or warm compressor. Three of the helium cooling circuits use altogether four identical cold circulators. Apart from the current leads which are supplied with the coolant from a LHe storage tank, the peak reserve power required is equal to 7 kW at 4.5 K entropy equivalent. However, this potential maximal demand occurs continuously for periods of only a few hours at most, and altogether for less than 1% of annual time. The refrigerator thus will be designed for 5 kW continuous power at 4.5 Kequiv. corresponding to 1.5 MW compressor connected rating. The reserve peak power will be covered, if necessary, by using the latent heat and vapour enthalpy of LHe from a storage tank. This supporting LHe stream is added to the phase separator and fed subsequently to the low pressure return stream at the cold end of the cold box. LN2-pre-cooling equipment of the cold box—which is installed for W7-X cool-down anyway—can also be used to increase refrigeration power. The LHe required for maintaining reserve refrigeration power as well as for running the current leads is generally produced overnight when W7-X is in idle current mode.

Bozhko, Y.; Schauer, F.

2003-09-01

378

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

379

Engineering analysis of the use of compression refrigerants in the thin polymer icemaker  

SciTech Connect

In previous studies the authors have developed the concept of an ice-making device constructed of thin polymer films, arranged so that when filled with a cold fluid they expand in a set of parallel tubes, on the exterior of which ice forms. When the ice is about one millimeter thick, the cold fluid is removed from the tubes and they collapse, being pulled away from the ice by a vacuum within. The device has been successfully demonstrated in a version where the tubes are filled with a water-ethylene glycol brine. This was followed by an economic assessment which indicated that the device would be even more competitive with existing systems if the compression refrigerant itself were admitted into the polymer film structure on which the ice forms. This report presents an engineering study of such a system, examines the outstanding questions which must still be answered and assesses the potential economics of the system. The authors develop preliminary designs for systems using R-134a and R-C318 as refrigerants which satisfy code requirements. They use standard thermodynamic and heat transfer analysis to determine expected performance for the systems, and combine this with component and assembly cost estimates to prepare life-cycle costs for the two new systems. Comparing them to commercially available systems, they find that these ``polymer evaporator`` systems seem to be completely feasible technically and that if they are successfully demonstrated, they should have substantial economic advantages over existing ice-making devices.

Leigh, R.; Andrews, J.

1995-11-01

380

Numerical Dynamic Simulation of Optimized Cross-Flow Heat Exchanger with Various Refrigerants  

NASA Astrophysics Data System (ADS)

Dynamic behaviors of fluid flow and interaction with the pipe material as well as the temperature are very useful in the design of heat exchangers. The information can be used to determine the effective operating condition and the limitation of the heat exchanger which will then benefited the manufacturers and consumers in terms of economy and safety. A single pass cross flow heat exchanger with conduction and forced convection heat transfer was represented by a mathematical model consist sets of partial differential equations. The equations were then transformed to non-dimensional form for the solution. A computer program was developed to solve the problem numerically. The governing equations were solved by finite difference method using implicit method. Five different types of refrigerant were used in the study; water, R-134a, R-23, R-22 and ammonia. Time response for steady state temperature then was determined and compared between the refrigerants which were then shows that ammonia has the shortest time response and water is the lowest steady state temperature. The results also showed that the tube length affects the air final temperature difference with the increase of temperature difference along with the tube length. The working fluid temperature difference was also affected by tube length with unique behaviors of the increase in temperature with respect to tube length. Finally, maximum air velocity showed the increase with working fluid velocity up to certain magnitude then the air velocity showed negligible change with the increase of working fluid velocity.

Osman, Kahar; Jong, Rudiyanto P.; Shariff, M. Shahril

2010-06-01

381

Correlation and prediction of the transport properties of refrigerants using two modified rough hard-sphere models  

SciTech Connect

Two methods are presented for the correlation and prediction of the viscosities and thermal conductivities of refrigerants R11, R12, R22, R32, R124, R125, R134a, R141b, and R152 and their mixtures. The first (termed RHS1) is a modified rough-hard-sphere method based on the smooth hard-sphere correlations of Assael et al. The method requires two or three parameters for characterizing each refrigerant but is able to correlate transport properties over wide ranges of pressure and temperature. The second method (RHS2) is also a modified rough-hard-sphere method, but based on an effective hard-sphere diameter for Lennard-Jones (LJ) fluids. The LJ parameters and the effective hard-sphere diameter required in this method are determined from a knowledge of the density-temperature behavior of the fluid at saturation. Comparisons with the rough-hard-sphere method of Assael and co-workers (RHS3) are shown. They also show that the RHS2 method can be used to correlate as well as predict the transport properties of refrigerants.

Teja, A.S.; King, R.K.; Sun, T.F. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Chemical Engineering; Smith, R.L. Jr. [Tohoku Univ., Sendai (Japan). Dept. of Chemical Engineering

1999-01-01

382

Soft Computing in Absorption Cooling Systems  

Microsoft Academic Search

\\u000a Absorption cooling systems make sense in many applications for process water cooling. Instead of mechanically compressing\\u000a a refrigerant gas, as in the conventional vapor compression process, absorption cooling uses a thermo-chemical process. Two\\u000a different fluids are used, a refrigerant and an absorbent. Heat directly from natural gas combustion, solar energy, waste-heat\\u000a source or indirectly from a boiler, drives the process.

Arzu ?ahin; Soteris Kalogirou

383

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

384

Neon turbo-Brayton cycle refrigerator for HTS power machines  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

385

Experimental measurement on characteristics of cool storage air conditioning system  

NASA Astrophysics Data System (ADS)

The experimental apparatus of cool storage air conditioning system is designed and constructed. The characteristics of cool storage air-conditioning system are experimentally measured. The temperature variation of coolant in the evaporator is presented by experiments. The refrigerant temperature in the evaporator and the compressor discharge temperature are also shown. The cool storage experiments are carried out to measure the refrigeration capacity of the chiller in cool storage mode, and the cool storage capacity in the storage tank. The measured results show that the coolant temperature difference between inlet and outlet in the evaporator, the refrigerant evaporating temperature, discharging temperature of the compressor and the refrigeration capacity of the chiller during cool storage period can maintain stable. The cool storage capacity in the storage tank approximately increases in linearity with cool storage time. This indicates the cool storage air conditioning system can stably operate.

Fang, Guiyin; Yang, Fan; Zhang, Man; Wu, Shuangmao

2008-12-01

386

Refrigerator and Solenoid Run Summary August\\/September 1999  

Microsoft Academic Search

The helium refrigerator was cooled down and operated for the third time since its installation. D-Zero's 2 Tesla superconducting solenoid was cooled down and operated for its second time since its installation into the D-Zero detector. This engineering note summarizes the cryogenic aspects of the test run and performance measurements made. The main purpose of this run was to do

R. Rucinski

1999-01-01

387

Air cooled absorption chillers for solar cooling applications  

NASA Astrophysics Data System (ADS)

The chemical composition of a 'best' absorption refrigerant system is identified, and those properties of the system necessary to design hot water operated, air cooled chilling equipment are determined. Air cooled chillers from single family residential sizes into the commercial rooftop size range are designed and operated.

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

1982-03-01

388

Laser cooling of solids  

Microsoft Academic Search

We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and

Richard I Epstein; Mansoor Sheik-bahae

2008-01-01

389

Laser cooling of solids  

SciTech Connect

We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

Epstein, Richard I [Los Alamos National Laboratory; Sheik-bahae, Mansoor [UNM

2008-01-01

390

Absorption refrigerators and coolers. (Latest citations from the US Patent Bibliographic File with Exemplary Claims). Published Search  

SciTech Connect

The bibliography contains citations of selected patents concerning the design and application of absorption refrigeration systems. Citations cover refrigeration, cooling/heating, and chilling devices. Combination heat pump/absorption and mechanical/absorption refrigeration systems are included. (Contains a minimum of 172 citations and includes a subject term index and title list.)

Not Available

1994-08-01

391

Laser cooling of solids  

Microsoft Academic Search

Laser cooling of solids, sometimes also known as optical refrigeration, is a fast developing area of optical science, investigating the interaction of light with condensed matter. Apart from being of fundamental scientific interest, this topic addresses a very important practical issue: design and construction of laser pumped solid-state cryocoolers, which are compact, free from mechanical vibrations, moving parts, fluids and

Galina Nemova; Raman Kashyap

2010-01-01

392

An adiabatic demagnetization refrigerator for SIRTF  

SciTech Connect

An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the Multiband Imaging Photometer of the Space Infrared Telescope Facility (SIRTF). The authors have built one such refrigerator which employs a ferric ammonium alum salt pill suspended by nylon threads in a 3 Tesla solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is <0.5 ..mu..W. The system has a hold time at 0.1 /sup 0/K of >12 hours. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built as a SIRTF prototype to fly on a balloon-borne telescope. It will employ a ferromagnetic shield. The possibility of using high T/sub c/ leads to the superconducting magnet and a solenoid-actuated heat switch are also discussed.

Timbie, P.T.; Bernstein, G.M.; Richards, P.L.

1989-02-01

393

Short time cycles of purely quantum refrigerators.  

PubMed

Four stroke Otto refrigerator cycles with no classical analog are studied. Extremely short cycle times with respect to the internal timescale of the working medium characterize these refrigerators. Therefore, these cycles are termed sudden. The sudden cycles are characterized by the stable limit cycle, which is the invariant of the global cycle propagator. During their operation the states of the working medium possess significant coherence which is not erased in the equilibration segments due to the very short time allocated. This characteristic is reflected in a difference between the energy entropy and the Von Neumann entropy of the working medium. A classification scheme for sudden refrigerators is developed allowing simple approximations for the cooling power and coefficient of performance. PMID:23004710

Feldmann, Tova; Kosloff, Ronnie

2012-05-10

394

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

395

DEVELOPMENT OF A REFRIGERANT DISTRIBUTION SECTION FOR ASHRAE STANDARD 152.  

SciTech Connect

In a recent draft report titled ''Impacts of Refrigerant Line Length on System Efficiency in Residential Heating and Cooling Systems Using Refrigerant Distribution,'' (Andrews 2000) some baseline calculations were performed to estimate various impacts on system efficiency of long refrigerant distribution lines. Refrigerant distribution refers to ''mini-splits'' and other types of space beating and cooling equipment that utilize refrigerant lines, rather than ducts or pipes, to transport heat and cooling effect from the outdoor unit to the building spaces where this heat or cooling is used. Five factors affecting efficiency were studied in each of the space conditioning modes (heating and cooling) for a total of ten factors in all. Temperature changes and pressure drops in each of the two refrigerant lines accounted for four of the factors, with the remaining one being elevation of the indoor unit relative to the outdoor unit. Of these factors, pressure drops in the suction line in cooling showed by far the largest effect. This report builds on these baseline calculations to develop a possible algorithm for a refrigerant distribution section of ASHRAE Standard 152. It is based on the approximate treatment of the previous report, and is therefore subject to error that might be corrected using a more detailed analysis, possibly including computer modeling and field testing. However, because the calculated efficiency impacts are generally small (a few percent being typical) it may be that the approximate treatment is sufficient. That question is left open for discussion. The purpose of this report is not to advocate the adoption of the methodology developed, but rather to present it as an option that could either be adopted as-is or used as a starting point for further analysis. It is assumed that the reader has available and is familiar with ASHRAE Standard 152P and with the previous analysis referred to above.

ANDREWS,J.W.

2001-09-07

396

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

397

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

398

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

399

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

400

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

401

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

402

Thermoacoustically driven refrigerator with double thermoacoustic-Stirling cycles  

NASA Astrophysics Data System (ADS)

Recently, considerable research efforts have been made to search substitution technologies for chlorofluorocarbon-based vapor compression cycles due to the concern over environmental issues. This letter introduces a helium-based thermoacoustic refrigeration system, which is a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine, for domestic refrigeration purpose. In the regenerators of both the refrigerator and the prime mover, helium gas experiences near to reversible high efficiency Stirling process. At the operating point with 3.0 MPa mean pressure, 57.7 Hz frequency, and 2.2 kW heat input, the experimental cooler provides a lowest temperature of -64.4 °C and 250 W cooling power at -22.1 °C. These results show good potential of the system to be an alternative in near future for domestic refrigeration with advantages of environment-friendliness, no moving parts, and heat driven mechanism.

Luo, Ercang; Dai, Wei; Zhang, Yong; Ling, Hong

2006-02-01

403

Pulse Tube Refrigerators for the Allen Telescope Array  

NASA Astrophysics Data System (ADS)

The Radio Astronomy Laboratory of the University of California, Berkeley is developing a 1 W at 80 K pulse tube refrigerator driven by a clearance seal linear compressor for use on the Allen Telescope Array. Second generation refrigerators show improved performance compared to the first generation, now achieving cooling power fairly close to model predictions. Compressors for the second-generation refrigerators are compact, electron-beam welded packages. One refrigerator was operated for 3070 hours, giving steady performance. For the third generation refrigerators we are hoping to better understand performance variations from one unit to another and to further improve the performance. Third generation units will have the reservoir integrated into the compressor and incorporate changes aimed at easier manufacturing.

Lugten, J. B.

2006-04-01

404

Ecological optimization for an irreversible magnetic Ericsson refrigeration cycle  

NASA Astrophysics Data System (ADS)

An irreversible Ericsson refrigeration cycle model is established, in which multi-irreversibilities such as finite-rate heat transfer, regenerative loss, heat leakage, and the efficiency of the regenerator are taken into account. Expressions for several important performance parameters, such as the cooling rate, coefficient of performance (COP), power input, exergy output rate, entropy generation rate, and ecological function are derived. The influences of the heat leakage and the time of the regenerative processes on the ecological performance of the refrigerator are analyzed. The optimal regions of the ecological function, cooling rate, and COP are determined and evaluated. Furthermore, some important parameter relations of the refrigerator are revealed and discussed in detail. The results obtained here have general significance and will be helpful in gaining a deep understanding of the magnetic Ericsson refrigeration cycle.

Wang, Hao; Wu, Guo-Xing

2013-08-01

405

Study on Operating Characteristics of A House Hold Stirling Refrigerator  

NASA Astrophysics Data System (ADS)

A prototype Stirling cycle refrigerator employing helium as a working fluid has been investigated to see whether the freon free machine be a viable alternative for the current household refrigerator. The prototype is a kinematics drive, and ? type Stirling cycle machine of 100W refrigeration. The performance was evaluated as a function of cooling head temperature, mean pressure, frequency, and cooling capacity. The prototype has achieved the targeted refrigeration of 100W, and the COP of 1.02 under the design operation condition; 16.7Hz frequency and 0.7MPa helium pressure. The performance data was compared with the predicted ones, which was obtained by the 3rd order computational method. It has been demonstrated that the performance is in a good agreement with the predicted in the whole range of operation condition.

Otaka, Toshio; Sakamoto, Moriyoshi; Murakami, Kazuhiko; Ota, Masahiro

406

Application of Cryocoolers to a Vintage Dilution Refrigerator  

SciTech Connect

A dilution refrigerator is required for 50mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80K and at 4K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

Schmitt, Richard; Smith, Gary; Ruschman, Mark; /Fermilab; Beaty, Jim; /Minnesota U.

2011-06-06

407

Multiple-Stage Evaporative Cooling for a High Desert Environment.  

National Technical Information Service (NTIS)

This paper will present the results of an analysis as to the utility of multiple-stage evaporative cooling as the potential replacement for mechanical refrigeration cooling. The high desert area of the southwest United States provides excellent summer wea...

R. E. Davis

1987-01-01

408

Performance comparison of magnetic refrigeration cycles  

NASA Astrophysics Data System (ADS)

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 of providing continuous cooling through magnetic refrigeration cycles and of extending the range of applications above near-absolute-zero temperatures have been investigated only in recent years. This paper reports the results of a parametric performance study of three magnetic refrigeration cycles using four rare-earth magnetic materials operating near their respective Curie temperatures. The thermodynamic cycles employed are the magnetic-equivalent Carnot, Ericsson, and ideal regenerative cycles, and the four magnetic materials are terbium, holmium, erbium, and thulium. Our findings show that the Carnot cycle is not possible for cases of temperature lift beyond 10 K for a magnetic field variation of 7 Tesla, that the performance and capacity of an ideal regenerative cycle are higher than that of the corresponding Ericsson cycle, and that the magnetocaloric effects of erbium and thulium seem to be too weak for practical applications.

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

409

Performance comparison of magnetic refrigeration cycles  

SciTech Connect

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 of providing continuous cooling through magnetic refrigeration cycles and of extending the range of applications above near-absolute-zero temperatures have been investigated only in recent years. This paper reports the results of a parametric performance study of three magnetic refrigeration cycles using four rare-earth magnetic materials operating near their respective Curie temperatures. The thermodynamic cycles employed are the magnetic-equivalent Carnot, Ericsson, and ideal regenerative cycles, and the four magnetic materials are terbium, holmium, erbium, and thulium. Our findings show that the Carnot cycle is not possible for cases of temperature lift beyond 10 K for a magnetic field variation of Tesla, that the performance and capacity of an ideal regenerative cycle are higher than that of the corresponding Ericsson cycle, and that the magnetocaloric effects of erbium and thulium seem to be too weak for practical applications. 14 refs., 14 figs.

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

1990-01-01

410

Single-molecule refrigerators: Substitution and gate effects  

NASA Astrophysics Data System (ADS)

Using a first-principles approach, we investigate the quantum cooling effects in single-molecule junctions. In comparison with the unsubstituted butanethiol single-molecule junction as a refrigerator, the amino-substituted butanethiol single-molecule junction shows significant enhancement in the coefficient of performance (COP). The enhancement is attributed to the appearance of new states in the neighborhood of chemical potentials due to amino substitution. The COP of butanethiol refrigerator can be improved further by the gate voltages.

Liu, Yu-Shen; Chen, Yu-Chang

2011-05-01

411

Combined cold compressor/ejector helium-refrigerator cycle  

SciTech Connect

A series of tests is reported as part of the program to demonstrate the feasibility of cold compressors as related to a large refrigerator. The use of a cold compressor in series with an ejector has been shown as an effective way to produce low pressure in a helium refrigeration system. Compared with a system which uses an ejector alone, the combined cold compressor and ejector system produces a lower temperature on the same load or more cooling at the same temperature. (LEW)

Schlafke, A.P.; Brown, D.P.; Wu, K.C.

1983-01-01

412

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

413

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

414

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

415

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

416

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

417

Development of the Los Alamos solid-state optical refrigerator  

NASA Astrophysics Data System (ADS)

Laser-induced cooling of a solid by net anti-Stokes fluorescence, first experimentally demonstrated in 1995, can be the basis of a new type of cryocooler, an optical refrigerator. This article describes the physics and design issues of a practical optical refrigerator for operation at 77 K. In particular, the Los Alamos Solid-State Optical Refrigerator (LASSOR) which we are developing would have an operating efficiency comparable to commercial small cryocoolers, be completely vibration-free and operate for years without maintenance.

Edwards, Bradley C.; Buchwald, Melvin I.; Epstein, Richard I.

1998-05-01

418

A solid-state refrigerator based on the electrocaloric effect  

NASA Astrophysics Data System (ADS)

The electrocaloric effect offers an attractive alternative to the Peltier effect for compact high-efficiency solid-state refrigeration. We report an implementation and experimental characterization of a continuous electrocaloric refrigeration cycle where we use switchable liquid-based thermal interfaces to achieve reliable high-contrast thermal switching between an electrocaloric material and a heat source/sink. The experimentally measured temporal temperature profiles of a cooling load agree well with transient heat transfer modeling results. Our work experimentally validates the feasibility of electrocaloric refrigeration and motivates further applied research on device development.

Jia, Yanbing; Sungtaek Ju, Y.

2012-06-01

419

Experimental Investigation of a Traveling-wave Refrigerator  

NASA Astrophysics Data System (ADS)

In this paper, a thermally-driven thermoacoustic refrigerator without any moving parts is reported. This refrigeration system consists of a thermoacoustic Stirling heat engine and a thermoacoustic Stirling refrigerator. Both the subsystems are designed to operate on traveling-wave mode. In the experiment, it is found that the Gedeon DC-flow has significant negative effect on both the heat engine and the refrigerator. To suppress these DC-flows, two flexible membranes were inserted into the two subsystems. The experiment demonstrates that they have worked very well. Then extensive experiments had been made to test the influence of various parameters on refrigeration performance of the whole system. The system has so far achieved a no-load temperature of -65°C, a cooling capacity of about 270 W at -20°C and 405 W at 0°C. In summary, the thermoacoustic refrigeration technology reported here shows a good prospect in room-temperature cooling such as food refrigeration and air-conditioning.

Luo, E. C.; Dai, W.; Zhang, Y.; Ling, H.

2006-04-01

420

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

421

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2013 CFR

...refrigerating systems serving any air conditioning or comfort-cooling system installed in a manufactured home shall employ a type of refrigerant that ranks no lower than Group 5 in the Underwriters' Laboratories, Inc. âClassification of Comparative Life Hazard...

2013-04-01

422

System for vaporizing carbon dioxide utilizing the heat by-product of the refrigeration system as a heat source  

SciTech Connect

The present invention is directed to a carbonation and refrigeration system wherein the heat of the refrigerant output side of the refrigeration compressor is utilized to vaporize liquid carbon dioxide into CO/sub 2/ gas which is introduced into a liquid product. The carbonation and refrigeration system successfully utilizes the heat of the refrigerant to vaporize the CO/sub 2/ liquid regardless of the cooling demand of the system caused by seasonal temperature variations. For example during the winter months when the cooling demand is as low as 10% of the cooling demand in the summer, the carbonation and refrigeration system operates effectively to vaporize the CO/sub 2/ liquid by means of a heat exchanger and a desuperheater which are connected in communication with the superheated vapor emerging from the output side of a refrigeration compressor. In addition, the carbonation and refrigeration system of the present invention cools more efficiently by extracting some of the heat from the condensed refrigerant entering the receiver of the refrigeration system. In this manner, the refrigeration compressor can operate more efficiently.

Shaw, H.L.

1980-12-23

423

Gas hydrate cool storage system  

DOEpatents

This invention is a process for formation of a gas hydrate to be used as a cool storage medium using a refrigerant in water. Mixing of the immiscible refrigerant and water is effected by addition of a surfactant and agitation. The difficult problem of subcooling during the process is overcome by using the surfactant and agitation and performance of the process significantly improves and approaches ideal.

Ternes, Mark P. (Knoxville, TN); Kedl, Robert J. (Oak Ridge, TN)

1985-01-01

424

Gas hydrate cool storage system  

DOEpatents

The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

Ternes, M.P.; Kedl, R.J.

1984-09-12

425

An adiabatic demagnetization refrigerator for infrared bolometers  

Microsoft Academic Search

Adiabatic demagnetization refrigerators have been built and installed in small portable liquid helium cryostats to test the feasibility of this method of cooling infrared bolometric detectors to temperatures below 0.3K. Performance has been achieved which suggests that bolometer temperatures of 0.2K can be maintained for periods of ˜60 hours. Applications to sensitive infrared detection from ground based telescopes and space

R. D. Britt; P. L. Richards

1981-01-01

426

An adiabatic demagnetization refrigerator for infrared bolometers  

Microsoft Academic Search

Adiabatic demagnetization refrigerators have been built and installed in small portable liquid helium cryostats to test the feasibility of this method of cooling infrared bolometric detectors to temperatures below 0.3K. Performance has been achieved which suggests that bolometer temperatures of 0.2K can be maintained for periods of ~60 hours. Applications to sensitive infrared detection from ground based telescopes and space

R. D. Britt; P. L. Richards

1981-01-01

427

Cooling system for superconducting magnet  

SciTech Connect

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir. 3 figs.

Gamble, B.B.; Sidi-Yekhlef, A.

1998-12-15

428

Cooling system for superconducting magnet  

DOEpatents

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir.

Gamble, Bruce B. (Wellesley, MA); Sidi-Yekhlef, Ahmed (Framingham, MA)

1998-01-01

429

Liquid over-feeding refrigeration system and method with integrated accumulator-expander-heat exchanger  

DOEpatents

A refrigeration system having a vapor compression cycle utilizing a liquid over-feeding operation with an integrated accumulator-expander-heat exchanger. Hot, high-pressure liquid refrigerant from the condenser passes through one or more lengths of capillary tubing substantially immersed in a pool liquid refrigerant in the accumulator-expander-heat exchanger for simultaneously sub-cooling and expanding the liquid refrigerant while vaporizing liquid refrigerant from the pool for the return thereof to the compressor as saturated vapor. The sub-cooling of the expanded liquid provides for the flow of liquid refrigerant into the evaporator for liquid over-feeding the evaporator and thereby increasing the efficiency of the evaporation cycle.

Mei, Viung C. (Oak Ridge, TN); Chen, Fang C. (Knoxville, TN)

1997-01-01

430

Liquid over-feeding refrigeration system and method with integrated accumulator-expander-heat exchanger  

DOEpatents

A refrigeration system is described having a vapor compression cycle utilizing a liquid over-feeding operation with an integrated accumulator-expander-heat exchanger. Hot, high-pressure liquid refrigerant from the condenser passes through one or more lengths of capillary tubing substantially immersed in a pool liquid refrigerant in the accumulator-expander-heat exchanger for simultaneously sub-cooling and expanding the liquid refrigerant while vaporizing liquid refrigerant from the pool for the return thereof to the compressor as saturated vapor. The sub-cooling of the expanded liquid provides for the flow of liquid refrigerant into the evaporator for liquid over-feeding the evaporator and thereby increasing the efficiency of the evaporation cycle. 4 figs.

Mei, V.C.; Chen, F.C.

1997-04-22

431

Thermal conductivity of a wide range of alternative refrigerants measured with an improved guarded hot-plate apparatus  

NASA Astrophysics Data System (ADS)

The thermal conductivity of the refrigerants R22, R123, R134a, R142b, R143a, and R152a has been determined as a function of temperature in the range from 300 to 460 K. Measurements were carried out at atmospheric pressure with an improved guarded hot-plate apparatus. The width of the instrument's gas layer and the temperature difference across the metering section were varied to detect any stray heat transfer. Radiation correction factors were derived from IR absorption spectra. The uncertainty of the measurements is estimated to be 2% at a standard deviation of less than 0.1%. All values are correlated with respect to temperature in the range covered. The equations are found to represent the results with average deviations of 1%. Our data sets are compared with corresponding hot wire results. In contrast to the generally preferred hot wire technique, with its possible electrical and chemical interactions between the wire and the polar refrigerant, there are no such difficulties using a guarded hot-plate apparatus. Our data sets may thus contribute to the discussions on discrepancies in thermal conductivity values from various authors using hot wire as one particular method.

Hammerschmidt, U.

1995-09-01

432

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

433

Counter-Top Thermoacoustic Refrigerator- An Experimental Investigation  

SciTech Connect

Thermoacoustic phenomenon is a new alternative refrigeration technology. Though design and fabrication is complex for getting the desired effect, it is environmentally friendly and successful system showed that it is relatively easy to run compared to the traditional vapor compression refrigeration system. Currently, theories supporting the thermoacoustic refrigeration systems are yet to be comprehensive to make them commercially viable. Theoretical, experimental, and numerical studies are being done to address the thermodynamics-acoustics interactions. In this study, experimental investigations were completed to test the feasibility of the practical use of a thermoacoustic refrigerator in its counter-top form for future specific application. The system was designed and fabricated based on linear acoustic theory. Acoustic power was given by a loud speaker and thermoacoustic effects were measured in terms of the cooling effects produced at resonanance. Investigations showed that discrepancies between designed and working resonance frequency exist. Thermoacoutic cooling improved at a certain frequency, achieved when the working frequency was varied away from the design frequency. A cooling effect of 4.8 K below the ambient temperature of 23.3 deg. C was obtained from the counter-top thermoacoustic system. This system uses no refrigerants and no compressor to generate the cooling effect, a potential to be further investigated for a practical system.

Anwar, Mahmood; Ghazali, Normah Mohd [Department of Thermo-Fluids, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor (Malaysia)

2010-06-28

434

Quantum refrigerators and the third law of thermodynamics.  

PubMed

The rate of temperature decrease of a cooled quantum bath is studied as its temperature is reduced to absolute zero. The third law of thermodynamics is then quantified dynamically by evaluating the characteristic exponent ? of the cooling process dT(t)/dt?-T^{?} when approaching absolute zero, T?0. A continuous model of a quantum refrigerator is employed consisting of a working medium composed either by two coupled harmonic oscillators or two coupled two-level systems. The refrigerator is a nonlinear device merging three currents from three heat baths: a cold bath to be cooled, a hot bath as an entropy sink, and a driving bath which is the source of cooling power. A heat-driven refrigerator (absorption refrigerator) is compared to a power-driven refrigerator. When optimized, both cases lead to the same exponent ?, showing a lack of dependence on the form of the working medium and the characteristics of the drivers. The characteristic exponent is therefore determined by the properties of the cold reservoir and its interaction with the system. Two generic heat bath models are considered: a bath composed of harmonic oscillators and a bath composed of ideal Bose/Fermi gas. The restrictions on the interaction Hamiltonian imposed by the third law are discussed. In the Appendices, the theory of periodically driven open systems and its implication for thermodynamics are outlined. PMID:23005070

Levy, Amikam; Alicki, Robert; Kosloff, Ronnie

2012-06-26

435

Quantum refrigerators and the third law of thermodynamics  

NASA Astrophysics Data System (ADS)

The rate of temperature decrease of a cooled quantum bath is studied as its temperature is reduced to absolute zero. The third law of thermodynamics is then quantified dynamically by evaluating the characteristic exponent ? of the cooling process (dT(t))/(dt)˜-T? when approaching absolute zero, T?0. A continuous model of a quantum refrigerator is employed consisting of a working medium composed either by two coupled harmonic oscillators or two coupled two-level systems. The refrigerator is a nonlinear device merging three currents from three heat baths: a cold bath to be cooled, a hot bath as an entropy sink, and a driving bath which is the source of cooling power. A heat-driven refrigerator (absorption refrigerator) is compared to a power-driven refrigerator. When optimized, both cases lead to the same exponent ?, showing a lack of dependence on the form of the working medium and the characteristics of the drivers. The characteristic exponent is therefore determined by the properties of the cold reservoir and its interaction with the system. Two generic heat bath models are considered: a bath composed of harmonic oscillators and a bath composed of ideal Bose/Fermi gas. The restrictions on the interaction Hamiltonian imposed by the third law are discussed. In the Appendices, the theory of periodically driven open systems and its implication for thermodynamics are outlined.

Levy, Amikam; Alicki, Robert; Kosloff, Ronnie

2012-06-01

436

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

437

Performance analysis of an adsorption refrigerator using activated carbon in a compound adsorbent  

Microsoft Academic Search

To improve the performance of the adsorption refrigeration of CaCl2–ammonia adsorption system, activated carbon has been distributed uniformly in the mass of CaCl2, thereby helping to enhance mass transfer and uplift the cooling power density. A multifunctional heat pipe adsorption refrigerator, in which activated carbon-CaCl2 is used as compound adsorbent and ammonia as refrigerant, is designed. Water and acetone are

Z. S. Lu; R. Z. Wang; L. W. Wang; C. J. Chen

2006-01-01

438

An exergy analysis of a solar-driven ejector refrigeration system  

Microsoft Academic Search

Exergy analysis is used as a tool to analyse the performance of an ejector refrigeration cycle driven by solar energy. The analysis is based on the following conditions: a solar radiation of 700 W\\/m2, an evaporator temperature of 10 °C, a cooling capacity of 5 kW, butane as the refrigerant in the refrigeration cycle and ambient temperature of 30 °C

Wimolsiri Pridasawas; Per Lundqvist

2004-01-01

439

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

440

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

441

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

442

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

443

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

444

Minimal Self-Contained Quantum Refrigeration Machine Based on Four Quantum Dots  

NASA Astrophysics Data System (ADS)

We present a theoretical study of an electronic quantum refrigerator based on four quantum dots arranged in a square configuration, in contact with as many thermal reservoirs. We show that the system implements the minimal mechanism for acting as a self-contained quantum refrigerator, by demonstrating heat extraction from the coldest reservoir and the cooling of the nearby quantum dot.

Venturelli, Davide; Fazio, Rosario; Giovannetti, Vittorio

2013-06-01

445

Transport Refrigeration Technician: Apprenticeship Course Outline. Apprenticeship and Industry Training. 4112  

ERIC Educational Resources Information Center

The graduate of the Transport Refrigeration Technician apprenticeship program is a certified journeyperson who will be able: (1) to diagnose repair, maintain and operate transport refrigeration equipment used to heat or cool the load as well as of diesel engines, APUs and other prime movers; (2) to use tools and equipment in order to carry out…

Alberta Advanced Education and Technology, 2012

2012-01-01

446

Flexible and cost efficient power consumption using economic MPC a supermarket refrigeration benchmark  

Microsoft Academic Search

Supermarket refrigeration consumes substantial amounts of energy. However due to the thermal capacity of the refrigerated goods, parts of the cooling capacity delivered can be shifted in time without deteriorating the food quality. In this paper we introduce a novel economic-optimizing MPC scheme that reduces operating costs by utilizing the thermal storage capabilities. In the study we specifically address advantages

Tobias Gybel Hovgaard; Lars F. S. Larsen; John Bagterp Jorgensen

2011-01-01

447

CFD Simulations of a Supersonic Ejector for Use in Refrigeration Applications  

Microsoft Academic Search

Supersonic ejectors have been used in cooling\\/refrigeration applications since the early 1900s. Interest in supersonic ejectors has been rekindled by recent efforts to reduce energy consumption; ejector refrigeration systems can be powered by solar energy or by waste heat generated by another process. This paper presents the results of computational fluid dynamics (CFD) simulations of a supersonic ejector for use

David Scott; Zine Aidoun; Omar Bellache; Mohamed Ouzzane

2008-01-01

448

Fractional Watt Vuillemier Cryogenic Refrigerator Program Engineering Notebook. Volume 2: Stress Analysis.  

National Technical Information Service (NTIS)

A structural analysis performed on the 1/4-watt cryogenic refrigerator. The analysis covered the complete assembly except for the cooling jacket and mounting brackets. Maximum stresses, margin of safety, and natural frequencies were calculated for structu...

W. S. Miller

1974-01-01

449

Ammonia usage in vapor compression for refrigeration and air-conditioning in the United States.  

National Technical Information Service (NTIS)

Ammonia provides high efficiency, low initial cost, and no detrimental impact to the environment. However, its toxicity and flammability, along with technical considerations and increased operating costs, deter its use in many refrigeration and cooling ap...

P. D. Fairchild V. D. Baxter

1995-01-01

450

Stirling Air Conditioner for Compact Cooling  

SciTech Connect

BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry to make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.

None

2010-09-01

451

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

452

Algor mortis: an erroneous measurement following postmortem refrigeration.  

PubMed

Determination of the time of death is one goal of medicolegal death investigations. Algor mortis has been used as a measure of the postmortem interval (PMI). We prospectively recorded the core temperatures of 19 adult bodies entering our morgue cooler and at 3, 6, and 9 h of refrigeration. We then compared the cooling rate with the calculated body mass index (BMI). For each individual body, the rate of cooling was fairly linear with no evidence of a plateau. There was fair to moderate correlation between the BMI and the cooling rate: cooling rate = -0.052 (BMI) + 3.52. The probability of linearity in any given case was 36%. Variables affecting this correlation included the presence and the layers of clothing and if the clothing was wet. Our data confirm that algor mortis is of very limited utility in determining the PMI in bodies that have been refrigerated. PMID:21644987

Wardak, Khalil S; Cina, Stephen J

2011-06-03

453

ISAC SC-LINAC PHASE-II HELIUM REFRIGERATOR COMMISSIONING AND FIRST OPERATIONAL EXPERIENCE AT TRIUMF  

SciTech Connect

ISAC Phase-II is an upgrade of the radioactive isotope superconducting linear accelerator, SC-linac, at TRIUMF. The Phase-I section of the accelerator, medium-beta, is operational and is cooled with a 600 W helium refrigerator, commissioned in March 2005. An identical refrigerator is being used with the Phase-II segment of the accelerator; which is now under construction. The second refrigerator has been commissioned and tested with the Phase-I section of the linac and is used for Phase-II linac development, including new SC-cavity performance tests. The commissioning of the Phase-II refrigeration system and recent operational experience is presented.

Sekachev, I.; Kishi, D.; Laxdal, R. E. [TRIUMF, Vancouver, BC, V6T 2A3 (Canada)

2010-04-09

454

Gifford-McMahon refrigerator with split cold head  

NASA Astrophysics Data System (ADS)

Leybold-Heraeus Co. have developed, built and successfully tested a Gifford-McMahon cryocooler with splitted cold head for cooling a cryopump. The refrigerating part of the cold head and the gas flow control device have been separated (splitted cold head) and the distance between them is bridged by only two thin lines for carrying the working gas. Due to this separation the size of the refrigerating part is virtually defined only by the size of the displacers whilst the gas flow control device can be of any desired design. It has been shown that dimensioning of the connecting lines and the corresponding losses became less critical with increasing size of the expander, but additional cooling in proportion to the refrigerating capacity is required.

Forth, H. J.; Heisig, R.; Klein, H. H.

1983-12-01

455

Performance bound for quantum absorption refrigerators  

NASA Astrophysics Data System (ADS)

An implementation of quantum absorption chillers with three qubits has been recently proposed that is ideally able to reach the Carnot performance regime. Here we study the working efficiency of such self-contained refrigerators, adopting a consistent treatment of dissipation effects. We demonstrate that the coefficient of performance at maximum cooling power is upper bounded by 3/4 of the Carnot performance. The result is independent of the details of the system and the equilibrium temperatures of the external baths. We provide design prescriptions that saturate the bound in the limit of a large difference between the operating temperatures. Our study suggests that delocalized dissipation, which must be taken into account for a proper modeling of the machine-baths interaction, is a fundamental source of irreversibility which prevents the refrigerator from approaching the Carnot performance arbitrarily closely in practice. The potential role of quantum correlations in the operation of these machines is also investigated.

Correa, Luis A.; Palao, José P.; Adesso, Gerardo; Alonso, Daniel

2013-04-01

456

The Magnetic Refrigerator for Temperatures below 1°k  

Microsoft Academic Search

The magnetic refrigerator is a device for maintaining isothermally a reservoir and\\/or experimental apparatus at temperatures below 1°k. Starting from temperatures maintained by a liquid helium bath the device produces cold by the magnetic cooling method, the cooling being performed in a cyclic manner. By cyclic operation temperatures below 1°k, as low as approximately 0.2°k, can be maintained continuously. In

J G Daunt

1957-01-01

457

Cryogenic refrigeration, volume 2. A bibliography with abstracts  

Microsoft Academic Search

Cryogenic cooling of electronic equipment, infrared equipment, infrared equipment, cryogenic storage vessels, magnetohydrodynamic generators, and superconducting magnets, coils, rotating machinery, and transmission lines is reported. Marine refrigeration of liquefied natural gas, cryogenic heat pipes, cryogenic heat transfer, and space applications are studied. Methods investigated include adiabatic demagnetization, electrocaloric effect, Joule-Thompson effect, thermoelectric cooling, and Crayton, Claude, Gifford-McMahon, Sterling, and Vuilleumier

W. E. Reed

1978-01-01

458

Cryogenic refrigeration, volume 3. A bibliography with abstracts  

Microsoft Academic Search

Cryogenic cooling of electronic equipment, infrared equipment, cryogenic storage vessels, magnetohydrodynamic generators, and superconducting magnets, coils, rotating machinery, and transmission lines is reported. Marine refrigeration of liquefied natural gas, cryogenic heat pipes, cryogenic heat transfer, and space applications are studied. Methods investigated include adiabatic demagnetization, electrocaloric effect, Joule-Thomson effect, thermoelectric cooling, and Crayton, Claude, Gifford-McMahon, Sterling, and Vuilleumier cycles. This

W. E. Reed

1978-01-01

459

Cryogenic refrigeration, volume 3. A bibliography with abstracts  

Microsoft Academic Search

Topics in the cited reports include cryogenic cooling of electronic equipment, infrared equipment, cryogenic storage vessels, magnetohydrodynamic generators, and superconducting magnets, coils, rotating machinery, and transmission lines. Marine refrigeration of liquefied natural gas, cryogenic heat pipes, cryogenic heat transfer, and space applications are studied. Methods investigated include adiabatic demagnetization, electrocaloric effect, Joule-Thomson effect, thermoelectric cooling, and Crayton, Claude, Gifford-McMahon, Sterling,

W. E. Reed

1979-01-01

460

Advances in dilution refrigeration in high magnetic fields  

Microsoft Academic Search

3He\\/4He dilution refrigerators have become a standard laboratory tool used to cool experiments to the milli-kelvin temperature range. Many of these applications involve the use of high magnetic fields. One system includes a 20.7 T superconducting magnet (the highest field ever achieved using multi filamentary superconducting wire in compact magnet form) and it can cool samples to 20 mK. Other

J. D. Hutchins; N. H. Balshaw; G. J. Batey; R. Ling; J. P. White; E. P. Whitehurst

1994-01-01

461

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

462

A review of emerging technologies for food refrigeration applications  

Microsoft Academic Search

Refrigeration has become an essential part of the food chain. It is used in all stages of the chain, from food processing, to distribution, retail and final consumption in the home. The food industry employs both chilling and freezing processes where the food is cooled from ambient to temperatures above 0°C in the former and between ?18°C and ?35°C in

S. A. Tassou; J. S. Lewis; Y. T. Ge; A. Hadawey; I. Chaer

2010-01-01

463

Acoustic streaming in pulse tube refrigerators: tapered pulse tubes  

Microsoft Academic Search

Acoustic streaming is investigated in tapered tubes with axially varying temperature, in the boundary layer limit. By appropriately shaping the tube, the streaming can be eliminated. Experimental data demonstrate that an orifice pulse tube refrigerator with a conical pulse tube whose cone angle eliminates streaming has more cooling power than one with either a cylindrical pulse tube or a conical

J. R. Olson; G. W. Swift

1997-01-01

464

Exergetic efficiency optimization for real regenerated air refrigerators  

Microsoft Academic Search

On the basis of the exergetic analysis, the performance analysis and optimization is carried out for irreversible regenerated air refrigerators by taking exergetic efficiency as the optimization objective using thermodynamic optimization in this paper. Exergetic efficiency is defined as the ratio of rate of exergy output to rate of exergy input of the system. The analytical formulas of the cooling

Lingen Chen; Youming Tu; Fengrui Sun

2011-01-01

465

A novel pressurized CHP system with water extraction and refrigeration  

Microsoft Academic Search

A novel Cooling, Heat, and Power (CHP) system has been proposed that features a semi-closed Brayton cycle with pressurized recuperation, integrated with a Vapor Absorption Refrigeration System (VARS). The semi-closed Brayton cycle is called the High Pressure Regenerative Turbine Engine (HPRTE). The VARS interacts with the HPRTE power cycle through heat exchange in the generator and the evaporator. Waste heat

J. R. Khan; W. E. Lear; S. A. Sherif; E. B. Howell; J. F. Crittenden; P. L. Meitner

2010-01-01

466

A Vuilleumier refrigerator for long-life spaceborne applications  

Microsoft Academic Search

A Vuilleumier refrigerator for spaceborne applications is under development with the following performance goals: a cooling power of simultaneously 1 W at 50 K and 5 W at 190 K, for an overall electrical consumption less than 250 W. Main features to achieve a long-life operation (over 50,000 hours) are the use of contactless hydrodynamic gas bearings, clearance seals and

A. Ravex; G. Claudet; P. Rolland

1990-01-01

467

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

468

Performance of the IFSMTF helium refrigerator in partial-array tests  

SciTech Connect

Performance of the International Fusion Superconducting Magnet Test Facility (IFSMTF) helium refrigerator in Partial Array Tests with three coils is described. The refrigerator was able to cool the coils and facility structure to 4.2 K in 20 days, with maximum temperature differentials of less than 50 K. Boiloff measurements were made for several components; only the lead dewars showed losses substantially higher than expected. Forced-flow cooling tests were also conducted. The coils and facility were warmed back to room temperature in 30 days. Several repairs and improvements were carried out. Results of another recent test on the refrigerator alone are reported.

Schwenterly, S.W.; Fietz, W.A.; Stamps, R.E.; Ellis, J.F.

1985-01-01

469

High-efficiency, ambient-assisted, integrated heating and cooling system  

SciTech Connect

A closed, ambient-energy-assisted system for heating and refrigeration with unidirectional refrigerant flow is described comprising: ambient energy, collector means for collecting heat energy from the ambient and exchanging the ambient heat to the refrigerant to product a super-heated gaseous refrigerant; compressor means downstream of the collector means for compressing the super-heated, gaseous refrigerant to a heated liquid refrigerant; first heat exchanger means downstream of the compressor means for exchanging heat from the heated liquid refrigerant to a heating load; precooler means downstream of the first heat exchanger means for exchanging heat from the heated liquid refrigerant to outside air for precooling the liquid refrigerant before the liquid refrigerant is expanded for cooling; first expansion valve means downstream of the precooler means for expanding the precooled liquid refrigerant to a gas, whereby the expanded refrigerant is chilled; second heat exchanger means downstream of the first expansion valve and upstream of the collector means for exchanging heat from a cooling load to the chilled refrigerant, second expansion valve means for expanding the liquid refrigerant, connectable downstream of the first heat exchanger and upstream of the collector means and in parallel with the precooler means, of the first expansion value means and the second heat exchanger means; and first selector valve means for selectively directing the refrigerant, responsive to a cooling load demand, to direct the hot liquid refrigerant from the first heat exchanger means to the precooler means in response to a cooling load demand and to direct the hot liquid refrigerant to the second expansion valve means otherwise, whereby the precooler means, the first expansion valve means and the second heat exchanger means are bypassed.

McEntire, B.

1988-02-02

470

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 refriger