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1

Floating Refrigerant Loop Based on R-134a Refrigerant Cooling of High-Heat Flux Electronics  

SciTech Connect

The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) have been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated power electronics is essential for the reliable operation of motors and power electronics. As part of a larger thermal control project, which includes shrinking inverter size and direct cooling of electronics, ORNL has developed U.S. Patent No. 6,772,603 B2, ''Methods and Apparatus for Thermal Management of Vehicle Systems and Components'' [1], and patent pending, ''Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant'' [2]. The floating-loop system provides a large coefficient of performance (COP) for hybrid-drive component cooling. This loop (based on R-134a) is integrated with a vehicle's existing air-conditioning (AC) condenser, which dissipates waste heat to the ambient air. Because the temperature requirements for cooling of power electronics and electric machines are not as low as that required for passenger compartment air, this adjoining loop can operate on the high-pressure side of the existing AC system. This arrangement also allows the floating loop to run without the need for the compressor and only needs a small pump to move the liquid refrigerant. For the design to be viable, the loop must not adversely affect the existing system. The loop should also provide a high COP, a flat-temperature profile, and low-pressure drop. To date, the floating-loop test prototype has successfully removed 2 kW of heat load in a 9 kW automobile passenger AC system with and without the automotive AC system running. The COP for the tested floating-loop system ranges from 40-45, as compared to a typical AC system COP of about 2-4. The estimated required waste-heat load for future hybrid applications is 5.5 kW and the existing system could be easily scaleable for this larger load.

Lowe, K.T.

2005-10-07

2

Predicting refrigerant inventory of R-134a in air-cooled condensers  

SciTech Connect

Currently, the refrigerant inventory for vapor-compression systems is determined using a costly trial-and-error procedure. An accurate computer model that predicts the amount of refrigerant in a system would reduce the time and expense of this process. This paper presents a computer model that has the capability to predict the amount of refrigerant in air-cooled condensers. For accurate prediction of refrigerant inventory, two important steps are required. The first step is to model the heat transfer of the coil in order to separate the three regions of the coil--desuperheating, condensing, and subcooling--and then to further divide the condensing region into increments of quality. The second step is to predict the void fraction (ratio of area occupied by gas to liquid) throughout the condensing region. Void fraction correlations by Domanski and Didion (1983), Hughmark (1962), Premoli et al. (1971), and Tandon et al. (1985) are included in the model. The simulation is used to model a cross-flow heat exchanger, with parallel refrigerant paths, used in mobile air-conditioning systems. The circulating refrigerant is R-134a. The model is exercised to illustrate the effects of different operating conditions and void fraction correlations on the refrigerant inventory in condensers. The results indicate that the prediction of refrigerant inventory is heavily influenced by both the selection of the void fraction correlation and the predicted length of the subcooling section in the condenser. This length is determined by the simulation program and is dependent on the correlations used to determine the heat transfer coefficients and pressure drop. It is as important for the condenser simulation to properly predict the outlet conditions as it is to predict the overall capacity of the coil. Inventory comparisons are provided using the refrigerant two-phase heat transfer correlation that most accurately predicts the condenser outlet conditions.

Orth, L.A.; Zietlow, D.C.; Pedersen, C.O. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering

1995-08-01

3

Comparative assessment of environment-friendly alternatives to R134a in domestic refrigerators  

Microsoft Academic Search

In the present work, the possibility of using R152a and hydrocarbon refrigerants (such as R290, R1270, R600a, and R600) as\\u000a alternatives to R134a in domestic refrigerators has been assessed theoretically. The refrigerants are assessed over wider\\u000a range condensing and evaporator temperatures. The assessment was done with standard parameters such as pressure ratio, volumetric\\u000a cooling capacity (VCC), coefficient of performance (COP),

M. Mohanraj; S. Jayaraj; C. Muraleedharan

2008-01-01

4

CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER  

E-print Network

1 CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER for evaporation heat transfer coefficient of refrigerant R-134a flowing in a plate heat exchanger. Correlation water-to-water experiment and a two-phase evaporation experiment with refrigerant R- 134a in a plate

Kandlikar, Satish

5

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

6

Experimental study of R152a and R32 to replace R134a in a domestic refrigerator  

Microsoft Academic Search

This paper presents an experimental study of R152a and R32, environment-friendly refrigerants with zero ozone depletion potential (ODP) and low global warming potential (GWP), to replace R134a in domestic refrigerator. A refrigerator designed and developed to work with R134a was tested, and its performance using R152a and R32 was evaluated and compared with its performance when R134a was used. The

B. O. Bolaji

2010-01-01

7

Pilot retrofit test of refrigerant R-134a for GDSCC  

NASA Technical Reports Server (NTRS)

NASA has issued an interim policy requiring all of its Centers to eliminate consumption (purchase) of stratospheric ozone-depleting substances, including chlorofluorocarbons (CFC's), by 1995. Also, plans must be outlined for the eventual phase out of their usage. The greatest source of CFC consumption and usage at the Goldstone Deep Space Communications Complex is refrigerant R-12, which is used in many of the facility's air-conditioning systems. A pilot retrofit test shows that retrofitting R-12 air-conditioning systems with hydrofluorocarbon R-13a would be a workable means to comply with the R-12 portion of NASA's policy. Results indicate acceptable cost levels and nearly equivalent system performance.

Albus, J.; Brown, B.; Dungao, M.; Spencer, G.

1994-01-01

8

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

9

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] [ORNL; Abdelaziz, Omar [ORNL] [ORNL; Vineyard, Edward Allan [ORNL] [ORNL

2012-01-01

10

Speed of Sound in the Liquid Phase of the R134a/152a Refrigerant Blend  

NASA Astrophysics Data System (ADS)

The speed of sound in the liquid phase of the binary blend of R134a and R152a and its components has been studied. The speed of sound was measured by means of the impulse method at a frequency of 2.1 MHz. The temperature range was 230 to 350 K at pressures up to 16 MPa. The values of speed of sound were measured with a standard error of not more than 0.25%. The results obtained for both components of the blend are represented with expressions based on a physical model. The standard deviation (versus the model) of the measured data is 0.09%, On the basis of the results obtained, the Redlich-Kister correlation has been used over the entire ranges of composition, temperature, and pressure to determine the speed of sound in the liquid phase and at the bubble point of the blend investigated.

Beliajeva, O. V.; Grebenkov, A. J.; Zajatz, T. A.; Timofejev, B. D.

1999-11-01

11

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

12

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

13

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

NASA Astrophysics Data System (ADS)

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 from p=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) saturated vapor, (iii) ideal gas (which equals approximately vapor state at ambient pressure). Finally the results are compared with data from the literature and also with the thermal conductivities of R12 and R11.

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

1992-11-01

14

Miniature Vapor Compressor Refrigeration System for Electronic Cooling  

Microsoft Academic Search

This paper experimentally investigated the thermal performance of a miniature vapor compressor refrigeration system using a thermal resistance model for electronic cooling. The evaporator, compressor, expansion valve, and condenser are the four main devices forming the refrigeration system with R-134a as a working fluid. The experimental parameters considered were the openings of the expansion valve and input heating power. The

Chih-Chung Chang; Nai-Wen Liang; Sih-Li Chen

2010-01-01

15

Comparative study of cryogen spray cooling with R-134a and R-404a: implications for laser treatment of dark human skin  

NASA Astrophysics Data System (ADS)

Cutaneous laser treatment in dark skin patients is challenging due to significant light absorption by the melanin at the basal layer of epidermis, which can result in irreversible nonspecific thermal injury to the epidermis. Cryogen spray cooling (CSC) with R-134a (boiling point ? -26.2°C at 1 atm), which is currently used during cutaneous laser treatment, has shown poor efficacy in protecting dark human skin. We investigated the potential of CSC with R-404a (boiling point ? -46.5°C at 1 atm), which has a lower boiling point than R-134a, for improved therapeutic outcome in dark human skin at three levels: in vitro (epoxy resin skin phantom), ex vivo (normal dark human skin sample), and in vivo (skin of the rabbit external ear). The skin phantom was used to acquire the surface and internal temperature profiles in response to CSC with R-134a or R-404a at various spurt durations, based upon which CSC-induced heat removal from the skin phantom was estimated using an algorithm that solved a one-dimensional inverse heat conduction problem. CSC with R-404a increased the temperature reductions within the phantom and subsequently the amount of heat removal from the phantom in comparison to that with R-134a. Normal ex vivo Fitzpatrick types V-VI human skin samples were used to investigate the thermal response of dark human skin epidermis to CSC (R-134a or R-404a) at various spurt durations in conjunction with 595-nm pulsed dye laser irradiation at various radiant exposures. Cryogen R-404a increased the threshold radiant exposures for irreversible thermal injury to the epidermis in dark pigmentation skin. No obvious CSC-induced morphological changes to human skin was observed when sprayed with R404-a spurts using durations up to 300 ms. In vivo rabbit ear vasculature was used as a model of cutaneous anomalies to assess the influences of CSC (with R-134a or R-404a) on the photothermolysis of dermal blood vessels. CSC (R-134a or R-404a) with the spurt durations of 100 to 300 ms increased the most superficial depth of thermally damaged dermal blood vessel compared with the sites without CSC, implying possible nonspecific cooling of superficial dermal blood vessels by the cryogen spurts with the settings applied.

Dai, Tianhong; Yaseen, Mohammad A.; Diagaradjane, Parmeswaran; Chang, David W.; Anvari, Bahman

2006-07-01

16

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

SciTech Connect

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 [theta] = [minus]20[degrees]C to 90[degrees]C and from p = O.1 bar to 60 bar respectively. The results are correlated with density and temperature. In addition temperature dependent correlations are presented for (1) saturated liquid, (2) saturated vapor, (3) ideal gas (which equals approximately vapor state at ambient pressure). Finally the results are compared with data from the literature and also with the thermal conductivities of R12 and R11. 35 refs., 14 figs., 8 tab.

Gross, U.; Song, Y.W.; Hahne, E. (Universitaet Stuttgart (Germany))

1992-01-01

17

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

18

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

19

The impact of fouling on performance of a vapor compression refrigeration system with integrated mechanical sub-cooling system  

Microsoft Academic Search

Performance characteristics due to fouling in a vapor compression cycle with integrated mechanical sub-cooling are investigated for various applications. Considering the first set of refrigerants i.e. R134a, R410A and R407C, from a first law standpoint, the COP indicates that R134a always performs better unless only the evaporator is being fouled. From a second law standpoint, the second-law efficiency indicates that

Bilal Ahmed Qureshi; Syed M. Zubair

2012-01-01

20

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

21

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

22

The effect of refrigerant combinations on performance of a vapor compression refrigeration system with dedicated mechanical sub-cooling  

Microsoft Academic Search

Performance characteristics due to use of different refrigerant combinations in vapor compression cycles with dedicated mechanical sub-cooling are investigated. For scratch designs, R134a used in both cycles produced the best results in terms of COP, COP gain and relative compressor sizing. In retrofit cases, considering the high sensitivity of COP to the relative size of heat exchangers in the sub-cooler

Bilal Ahmed Qureshi; Syed M. Zubair

23

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

24

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

25

Compressor Calorimeter Test of R-404A Alternatives ARM-31a, D2Y-65, L-40, and R32 + R-134a Mixture using a Scroll Compressor  

SciTech Connect

As a contribution to the AHRI Low-GWP Alternative Refrigerants Evaluation Program (AREP), this study compares the performance of four lower-GWP alternative refrigerants, ARM-31a, D2Y-65, L-40, and R-32 + R-134a mixture, to that of refrigerant R-404A (baseline) in a scroll compressor designed for medium temperature refrigeration applications. These comparisons were carried out via compressor calorimeter tests performed on a compressor designed for refrigerant R-404A and having a nominal rated capacity of 23,500 Btu/hr. Tests were conducted over a suction dew point temperature range of -10 F to 35 F in 5 F increments and a discharge dew point temperature range of 70 F to 140 F in 10 F increments. All the tests were performed with 20 F superheat, 40 F superheat, and 65 F suction temperature. A liquid subcooling level of 10 F to 15 F was maintained for all the test conditions. However, the cooling capacities reported in this study are normalized for 0 F subcooling. The tests showed that the compressor energy efficiency ratio (EER) and cooling capacity with all four alternative refrigerants tested are higher at higher saturation suction and saturation discharge temperature and lower at lower saturation suction and saturation discharge temperature, compared to that of R-404A. Discharge temperatures of all the alternative refrigerants were higher than that of R-404A at all test conditions.

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

2013-08-01

26

Performance of ejector cooling systems using low ecological impact refrigerants  

Microsoft Academic Search

The theoretical behaviour of an ejector cooling system, using as working fluids propane, butane, isobutane, R152a and R134a, is obtained. The ejector works as a thermo-compressor that is simulated with a validated one-dimensional mathematical model, whose errors are lower than 6%. For a system unitary cooling capacity, a parametric study is carried out varying the generation, condensation and evaporation temperatures.

Raul Roman; Jorge I. Hernandez

2011-01-01

27

R-134a (1,1,1,2-Tetrafluoroethane) Inhalation Induced Reactive Airways Dysfunction Syndrome.  

PubMed

R-134a (1,1,1,2-tetrafluoroethane) is widely used as a refrigerant and as an aerosol propellant. Inhalation of R-134a can lead to asphyxia, transient confusion, and cardiac arrhythmias. We report a case of reactive airways dysfunction syndrome secondary to R-134a inhalation. A 60-year-old nonsmoking man without a history of lung disease was exposed to an air conditioner refrigerant spill while performing repairs beneath a school bus. Afterward, he experienced worsening shortness of breath with minimal exertion, a productive cough, and wheezing. He was also hypoxic. He was admitted to the hospital for further evaluation. Spirometry showed airflow obstruction with an FEV1 1.97 L (45% predicted). His respiratory status improved with bronchodilators and oral steroids. A repeat spirometry 2 weeks later showed improvement with an FEV1 2.5 L (60% predicted). Six months after the incident, his symptoms had improved, but he was still having shortness of breath on exertion and occasional cough. PMID:25137406

Doshi, Viral; Kham, Nang; Kulkarni, Shreedhar; Kapitan, Kent; Henkle, Joseph; White, Peter

2014-08-18

28

Natural Refrigerant, Geothermal Heating & Cooling Solutions  

E-print Network

Natural Refrigerant, Geothermal Heating & Cooling Solutions Lalit Chordia, PhD, Marc Portnoff 150.thargeo.com Thar Geothermal, LLC © 2013 All Rights Reserved CO2MFORT ADVANTAGE Nature's Talk Outline · Introduction to Thar Geothermal · Carbon Dioxide (R744) the Environmentally Exceptional Refrigerant · Thar

29

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

30

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

31

Cooling performance and energy saving of a compression–absorption refrigeration system assisted by geothermal energy  

Microsoft Academic Search

The objectives of this paper are to develop a novel combined refrigeration system, and to discuss the thermodynamic analysis of the cycle and the feasibility of its practical development. The aim of this work was to study the possibility of using geothermal energy to supply vapour absorption system cascaded with conventional compression system. Three working fluids (R717, R22, and R134a)

L. Kairouani; E. Nehdi

2006-01-01

32

Entanglement enhances cooling in microscopic quantum refrigerators.  

PubMed

Small self-contained quantum thermal machines function without external source of work or control but using only incoherent interactions with thermal baths. Here we investigate the role of entanglement in a small self-contained quantum refrigerator. We first show that entanglement is detrimental as far as efficiency is concerned-fridges operating at efficiencies close to the Carnot limit do not feature any entanglement. Moving away from the Carnot regime, we show that entanglement can enhance cooling and energy transport. Hence, a truly quantum refrigerator can outperform a classical one. Furthermore, the amount of entanglement alone quantifies the enhancement in cooling. PMID:24730798

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

2014-03-01

33

Application of refrigeration system in electronics cooling  

Microsoft Academic Search

An experimental investigation of the transient response of the vapor compression refrigeration (VCR) system to rapid change in evaporator (simulated electronics) heat load is presented. In this study, the VCR system is designed and constructed specifically for applications to cool high heat flux electronics and high-end computers. Temperature and pressure data were measured at pre-selected locations to study the behavior

A. G. Agwu Nnanna

2006-01-01

34

Effect of EHD on heat transfer enhancement during two-phase condensation of R-134a at high mass flux in a horizontal smooth tube  

NASA Astrophysics Data System (ADS)

In this study, effect of electrohydrodynamic (EHD) on the condensation heat transfer enhancement and pressure drop of pure R-134a are experimentally investigated. The test section is a 2.5 m long counterflow double tube heat exchanger with refrigerant flowing in the inner tube and cooling water flowing in the annulus. The inner tube is made from smooth horizontal copper tubing of 9.52 mm outer diameter. The electrode is made from stainless steel wire of 1.47 mm diameter. The test runs are performed at average saturated temperatures ranging between 40 and 60°C, mass flux ranging between 200 and 600 kg/m2 s, heat flux ranging between 10 and 20 kW/m2 and applied voltage at 2.5 kV. For the presence of the electrode, the experimental results indicate that the maximum heat transfer enhancement ratio is around 30% while the maximum increase in pressure drop is about 25%.

Laohalertdecha, Suriyan; Wongwises, Somchai

2007-07-01

35

Thermal stability of R-134a, R-141b, R-13I1, R-7146, R-125 associated with stainless steel as a containing material  

Microsoft Academic Search

An experimental apparatus for assessing the thermal stability threshold of refrigerant working fluids is described and results for R-134a (1,1,1,2-tetrafluoroethane), R141b (1,1-dichloro-1-fluoroethane), R-13I1 (trifluoromethyl iodide), R-7146 (sulphur hexafluoride), R-125 (pentafluoroethane) are presented. The information is a concern for the design of refrigeration systems, high temperature heat pumps and Organic Rankine Cycles (ORC), for which the above refrigerants are proposed. The

Ludovico Calderazzi; Piero Colonna di Paliano

1997-01-01

36

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

37

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

38

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

39

R12 VE R134a SO?UTUCU AKI?KANLARI KULLANAN OTOMOB?L ?KL?MLEND?RME S?STEM?N?N DENEYSEL PERFORMANS ANAL?Z?  

Microsoft Academic Search

In this study, an automobile air conditioning (AAC) system charged with R12 and R134a refrigerants was operated at various compressor speeds and thermal loads, and a comparative performance analysis for both refrigerant cases was conducted. For this aim, an experimental AAC system consisting of a compressor, an evaporator, a condenser and a thermostatic expansion valve was set up. The compressor

Dilek Özlem; Makine E?itimi Bölümü

40

Experimental analysis of R134a flow boiling inside a 5 PPI copper foam  

NASA Astrophysics Data System (ADS)

Heat dissipation is one of the most important issues for the reliability of electronic equipment. Boiling can be a very efficient heat transfer mechanism when used to face with the electronic technology needs of efficient and compact heat sinks. Recently, cellular structured materials both stochastic and periodic, particularly open cell metal foams, have been proposed as possible enhanced surfaces to lower the junction temperatures at high heat fluxes. Up today, most of the research on metal foams only regards single phase flow, whereas the two phase flow is still almost unexplored. This paper presents an experimental study on the heat transfer of R134a during flow boiling inside a 5 PPI (Pores Per linear Inch) copper foam, which is 5 mm high, 10 mm wide and 200 mm long, and it is brazed on a 10 mm thick copper plate. The experimental measurements were carried out by imposing three different heat fluxes (50, 75, and 100 kW m-2) and by varying the refrigerant mass velocity between 50 and 200 kg m-2 s-1 and the vapour quality from 0.2 to 0.90, at constant saturation temperature (30°C). The effects of the refrigerant mass flow rate, heat flux and vapour quality on the heat transfer coefficient, dry out phenomenon, and pressure drop are studied.

Diani, A.; Mancin, S.; Rossetto, L.

2014-04-01

41

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

42

Cooling at the quantum limit and RF refrigeration  

E-print Network

31 (2002) #12;Electromagnetic transfer of heat (photons) Lattice Electrical environment Electron (electromagnetic) heat transport Cooling at the quantum limit: experiments RF refrigeration in a single;Conclusions Electromagnetic thermal coupling becomes important in small circuits at very low temperatures

Fominov, Yakov

43

Hybrid vapor compression refrigeration system with an integrated ejector cooling cycle  

Microsoft Academic Search

A refrigeration system was developed which combines a basic vapor compression refrigeration cycle with an ejector cooling cycle. The ejector cooling cycle is driven by the waste heat from the condenser in the vapor compression refrigeration cycle. The additional cooling capacity from the ejector cycle is directly input into the evaporator of the vapor compression refrigeration cycle. The governing equations

Yinhai Zhu; Peixue Jiang

44

Comparitive analysis of an automotive air conditioning systems operating with CO 2 and R134a  

Microsoft Academic Search

This paper evaluates performance merits of CO2 and R134a automotive air conditioning systems using semi-theoretical cycle models. The R134a system had a current-production configuration, which consisted of a compressor, condenser, expansion device, and evaporator. The CO2 system was additionally equipped with a liquid-line\\/suction-line heat exchanger. Using these two systems, an effort was made to derive an equitable comparison of performance;

J. Steven Brown; Samuel F. Yana-Motta; Piotr A. Domanski

2002-01-01

45

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

46

R1234yf vs. R134a Flow Boiling Heat Transfer Inside a 3.4 mm ID Microfin Tube  

NASA Astrophysics Data System (ADS)

The refrigerant charge minimization as well as the use of eco-friendly fluids can be considered two of the most important targets for these applications to cope with the new environmental challenges. This paper compares the R1234yf and R134a flow boiling heat transfer and pressure drop measurements inside a small microfin tube with internal diameter at the fin tip of 3.4 mm. This study is carried out in an experimental facility built at the Dipartimento di Ingegneria Industriale of the University of Padova especially designed to study both single and two phase heat transfer processes. The microfin tube is brazed inside a copper plate and electrically heated from the bottom. Several T -type thermocouples are inserted in the wall to measure the temperature distribution during the phase change process. In particular, the experimental measurements were carried out at constant saturation temperature of 30 °C, by varying the refrigerant mass velocity between 190 kg m?2 s?1 and 940 kg m?2 s?1, the vapour quality from 0.2 to 0.99, at different imposed heat fluxes. The two refrigerants are compared considering the values of the two-phase heat transfer coefficient and pressure drop.

Diani, A.; Mancin, S.; Rossetto, L.

2014-11-01

47

Comparison of dilution effects of R134a and nitrogen on flammable hydrofluorocarbons  

NASA Astrophysics Data System (ADS)

An experimental apparatus has been built to measure the flammability limits of combustible gases based on Chinese national standard GB/T 12474-90. The flammability limits of four binary mixtures of R161/R134a, R152a/R134a, R161/N2 and R152a/N2 were measured with this apparatus at atmospheric pressure and ambient temperature. The fuel inertization points (FIP) of these mixtures can be found from the envelopes. Comparisons were made with the literature data; good agreement for most measurements was obtained. R134a was found to have a better dilution effect than nitrogen in reducing the flammability of hydrofluorocarbons.

Li, Zhenming; Gong, Maoqiong; Wu, Jianfeng; Zhou, Yuan

2009-12-01

48

Cooling an electron gas using quantum dot based electronic refrigeration  

E-print Network

and theoretical investigation of a re- frigeration scheme that has the potential to cool 2DEGs below the temperatures currently available. Cooling to ever lower temperatures would be beneficial for studying fragile fractional quantum Hall states, non-Fermi-liquid... dots. Conventionally, low temperature measurements of 2DEGs are made by cooling the sample to 1.5 K with liquid Helium-4, to 300 mK with liquid Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron...

Prance, Jonathan Robert

2009-10-13

49

Comparison of dilution effects of R134a and nitrogen on flammable hydrofluorocarbons  

Microsoft Academic Search

An experimental apparatus has been built to measure the flammability limits of combustible gases based on Chinese national\\u000a standard GB\\/T 12474-90. The flammability limits of four binary mixtures of R161\\/R134a, R152a\\/R134a, R161\\/N2 and R152a\\/N2 were\\u000a measured with this apparatus at atmospheric pressure and ambient temperature. The fuel inertization points (FIP) of these\\u000a mixtures can be found from the envelopes. Comparisons

Zhenming Li; Maoqiong Gong; Jianfeng Wu; Yuan Zhou

2009-01-01

50

Thermal conductivity of R32 and its mixture with R134a  

SciTech Connect

The liquid thermal conductivity of R32 (CH{sub 2}F{sub 2}) and R134a (CF{sub 3}CH{sub 2}F) was measured in the range from 223 to 323 K and from 2 to 20 MPa by the transient hot-wire method. The thermal conductivity of the R32+R134a mixture was also measured in the same range by varying the mass fraction of R32. The measured data are analyzed to obtain a correlation in terms of temperature, pressure and composition of the mixture. The uncertainty of our measurements is estimated to be within {+-}2%.

Ro, S.T.; Kim, J.Y.; Kim, D.S. [Seoul National Univ. (Korea, Republic of)

1995-09-01

51

Cryogenic optical refrigeration: Laser cooling of solids below 123 K  

NASA Astrophysics Data System (ADS)

This dissertation compiles recent achievements in optical refrigeration, cooling a 10% wt. Ytterbium doped Yttrium Lithium Fluoride (Yb+3:YLF) crystal via anti-Stokes fluorescence to a record low temperature ~114(+/-1)K (below NIST-defined cryogenic 123 K) from room temperature (DeltaT ~185 K) in a single stage with a cooling power of 190mW. The demonstration of the coldest temperature to date, without the use of liquid cryogens or mechanical refrigerators, is achieved by taking advantage of the Stark manifold resonance and high doping concentration available in a crystalline host, outperforming multi-stage Peltier coolers. A novel technique probing local temperature changes experimentally verifies the cooling efficiency model with expected cooling to 93 K with the current crystal. With modest improvements to parasitic background absorption through the reduction of identified impurities, theory predicts cooling that approaches liquid nitrogen temperatures at 77 K. With this accomplishment, implementation of all solid-state cryo-cooling has begun.

Melgaard, Seth D.

52

Computer Programs for Calculating the Isentropic Flow Properties for Mixtures of R-134a and Air  

NASA Technical Reports Server (NTRS)

Three computer programs for calculating the isentropic flow properties of R-134a/air mixtures which were developed in support of the heavy gas conversion of the Langley Transonic Dynamics Tunnel (TDT) from dichlorodifluoromethane (R-12) to 1,1,1,2 tetrafluoroethane (R-134a) are described. The first program calculates the Mach number and the corresponding flow properties when the total temperature, total pressure, static pressure, and mole fraction of R-134a in the mixture are given. The second program calculates tables of isentropic flow properties for a specified set of free-stream Mach numbers given the total pressure, total temperature, and mole fraction of R-134a. Real-gas effects are accounted for in these programs by treating the gases comprising the mixture as both thermally and calorically imperfect. The third program is a specialized version of the first program in which the gases are thermally perfect. It was written to provide a simpler computational alternative to the first program in those cases where real-gas effects are not important. The theory and computational procedures underlying the programs are summarized, the equations used to compute the flow quantities of interest are given, and sample calculated results that encompass the operating conditions of the TDT are shown.

Kvaternik, Raymond G.

2000-01-01

53

Gifford-McMahon/Joule-Thomson Refrigerator Cools to 2.5 K  

NASA Technical Reports Server (NTRS)

A compact refrigerator designed specifically for cooling a microwave maser low-noise amplifier is capable of removing heat at a continuous rate of 180 mW at a temperature of 2.5 K. This refrigerator is a combination of (1) a commercial Gifford-McMahon (GM) refrigerator nominally rated for cooling to 4 K and (2) a Joule-Thomson (J-T) circuit. The GM refrigerator pre-cools the J-T circuit, which provides the final stage of cooling. The refrigerator is compact and capable of operating in any orientation. Moreover, in comparison with a typical refrigerator heretofore used to cool a maser to 4.5 K, this refrigerator is simpler and can be built at less than half the cost.

Britcliffe, Michael; Fernandez, Jose; Hanson, Theodore

2005-01-01

54

Positive Displacement Compressor Technology for Refrigeration  

NASA Astrophysics Data System (ADS)

Trends of compressor technologies for refrigerators, freezers and condensing units are presented in this paper. HFC refrigerants such as R134a and R404C are promising candidates as an altemative for R12. Performance of reciprocating and rotary compressors in the operation with R134A is described. In addition, compressor technologies such as efficiency improvement are described in the cases of reciprocating, rotary and scroll compressors.

Nagatomo, Shigemi

55

Miniature vapor compression refrigeration systems for active cooling of high performance computers  

Microsoft Academic Search

A small refrigeration system for cooling of computer system components is evaluated. A thermodynamic model describing the performance of the cycle along with a computer simulation program is developed to evaluate its performance. The refrigeration system makes use of a miniature reciprocating vapor compression compressor. Due to space limitations in some high performance computer servers, a miniature refrigeration system composed

Ali Heydari

2002-01-01

56

Microminiature refrigerators for Joule-Thomson cooling of electronic chips and devices  

NASA Astrophysics Data System (ADS)

The speed, reliability, and noise characteristics of most semiconductor devices improve with cooling to cryogenic temperatures. In addition, certain unique capabilities become available at these temperatures through the use of superconducting electronics. Progress in the development of the technology for the selective or 'spot cooling' of devices and individual chips using microminiature Joule-Thomson refrigerators for the lower temperature range is discussed. Also discussed are the recent developmet of circuit board coolers for higher temperature applications for the cooling of CMOS, PALs, SRAM and DRAM devices, using related, compressed vapor refrigerators with higher refrigeration capacity than the low temperature, J-T refrigerators.

Little, W. A.

57

Performance degradation of a vapor compression refrigeration system under fouled conditions  

Microsoft Academic Search

Performance degradation due to fouling in a vapor compression cycle is investigated for various applications. Considering the first set of refrigerants i.e. R134a, R410A and R407C, from a first law standpoint, the COP indicates that R134a always performs better unless only the evaporator is being fouled. In contrast to this, from a second-law standpoint, the second-law efficiency indicates that R134a

Bilal Ahmed Qureshi; Syed M. Zubair

2011-01-01

58

Condensation stage of a pulse tube pre-cooled dilution refrigerator  

Microsoft Academic Search

In our article, experiments with a pulse tube (PTR) pre-cooled dilution refrigerator (DR) are presented, where an upgraded 3He condensation stage has been tested. The DR had a 3He flow rate of up to 1.1mmol\\/s. The 3He gas entering the refrigerator was first pre-cooled to a temperature of ?50K at the first stage of the PTR. In the next cooling

Kurt Uhlig

2008-01-01

59

Study of new cool storage materials for refrigerated vehicle in cold chain  

Microsoft Academic Search

Refrigerated vehicles can not be neglected in cold chain. The research status of cool storage technology used in refrigerated vehicles was summarized, the advantage and deficiency of hydrated crystalline salt storage and organic matter storage were compared and analyzed. Moreover, the thermal performance of a new phase change material (PCM) including melting point and undercooling during the phase change process

Li Xiaoyan; Yang Shuting; Zhou Dong

2010-01-01

60

Viscosity and thermal conductivity of methane, ethane and propane halogenated refrigerants  

Microsoft Academic Search

In the case of the methane and ethane halogenated refrigerants, the examination of the available viscosity and thermal conductivity measurements, allowed the derivation and recommendation of standard equations for these two properties. Hence, equations for the viscosity of refrigerants R32, R124, R125, R134a, R141b, and R152a in the liquid phase and refrigerants R125, R134a, R142b and R152a in the vapor

Marc J Assael; Natassa K Dalaouti; Katerina E Gialou

2000-01-01

61

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

62

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

63

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

64

Microjet array single-phase and flow boiling heat transfer with R134a Eric A. Browne a  

E-print Network

of a submerged microjet array was conducted with R134a. The staggered array of seventeen 112-lm diameter orifices studies have been performed [25­30] but mostly with single jets. This study employs an array of submerged the pressure in the loop. Pre- scribed inlet temperatures were achieved

Peles, Yoav

65

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

66

In-tube heat transfer and pressure drop of R-134a and ester lubricant mixtures in a smooth tube and a micro-fin tube. Part 2: Condensation  

SciTech Connect

Average in-tube heat transfer coefficients and pressure drops during condensation are reported for condensation of refrigerant R-134a/lubricant mixtures in a smooth tube and a micro-fin tube of 9.52-mm (3/8-in.) outer diameter. The lubricants tested were 169-SUS and 369-SUS penta erythritol ester mixed acids. Lubricant concentrations ranged from 0% to 5%. The average saturation temperature in the test tube was approximately 40 C (104 F). The mass flux of the refrigerant-lubricant mixtures was varied from 85 kg/m{sup 2}{center_dot}s (62,700 lb/ft{sup 2}{center_dot}h) to 375 kg/m{sup 2}{center_dot}s (276,640 lb/ft{sup 2}{center_dot}h). Heat transfer coefficients during condensation decreased with the addition of lubricants in all cases. Condensation pressure drops increased with the addition of the 169-SUS ester lubricant in both the smooth tube and the micro-fin tube. The addition of the 369-SUS lubricant did not affect pressure drops in the smooth tube, but it decreased the pressure drops in the micro-fin tube. Pure R-134a heat transfer coefficients in the micro-fin tube were 100% to 200% higher than those in the smooth tube, with the higher values occurring at the lower mass fluxes. Pressure drops in the micro-fin tube were 20% to 50% higher than those in the smooth tube. Design equations are presented that aid in predicting the heat transfer coefficients and pressure drops of R-134a/lubricant mixtures in the smooth and micro-fin tubes.

Eckels, S.J. [Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering; Doerr, T.M.; Pate, M.B. [Iowa State Univ., Ames, IA (United States). Dept. of Mechanical Engineering

1994-12-31

67

Continuous Magnetic Refrigerators for Cooling in the 0.05 to 10 K Range  

NASA Technical Reports Server (NTRS)

Low temperature refrigeration is an increasingly vital technology for NASA's Space Science program since most detectors being developed for x-ray, IR and sub-millimeter missions must be cooled to below 100 mK in order to meet the requirements for energy and spatial resolution. For space applications, magnetic refrigeration has an inherent advantage over alternative techniques because it does not depend on gravity. Adiabatic demagnetization refrigerators, or ADRs, are relatively simple, solid state devices. The basic elements are a magnetocaloric refrigerant (usually an encapsulated paramagnetic salt) located in the bore of a superconducting magnet, and a heat switch linking the salt to a heat sink. The alignment of magnetic spins with the magnetic field causes the refrigerant to warm as the magnetic field increases and cool as the field decreases. Thus the simple process of magnetizing the refrigerant to high field with the heat switch closed, then demagnetizing it with the heat switch open allows one to obtain temperatures well below 100 mK using a heat sink as warm as 4.2 K. The refrigerant can maintain a low temperature for a length of time depending on the applied and parasitic heat loads, its mass, and the initial magnetic field strength. Typically ADRs are designed for 12-24 hours of hold time, after which they must be warmed up and recycled.

Shirron, Peter; DiPirro, Michael; Canavan, Edgar; Tuttle, James; Panek, John; Jackson, Michael; King, Todd; Numazawa, Takenori; Krebs, Carolyn (Technical Monitor)

2001-01-01

68

Large cooling power hybrid Gifford mac Mahon / Joule Thomson refrigerator andliquefier  

NASA Astrophysics Data System (ADS)

In this paper, we present two refrigerators using Joule Thomson cycle providing cooling powers of 4.5 W at 4.4 K and using Gifford Mac Mahon cryocoolers for the precooling. Several smaller machines have been developped in our laboratory with refrigeration capacity ranging from 100 mW up to 1.5 W in the temperature range 3 K to 4.4 K. In the present case, to increase the cooling power, we introduced a three stage precooling scheme using a liquid nitrogen vessel plus the two stages of a Gifford Mac Mahon cryocooler. Cooldown and operation of the system are fully automatic. The first refrigerator is used to cool two Nb 3Sn superconducting coils having a maximum field of 11.8 T. The second system is an helium liquefier, designed to produce more than 1 liter per hour.

Poncet, Jean-Marc; Claudet, Gérard; Lagnier, Robert; Ravex, Alain

69

Experimental study on performance of automotive air conditioning system using R-152a refrigerant  

Microsoft Academic Search

Recently, as climate changes have manifested worldwide, every country is making efforts to prevent ozone depletion and global\\u000a warming. In the automotive industry, R-134a refrigerant is widely used in air conditioning systems because it has zero ozone\\u000a depletion potential (ODP). Unfortunately, its global warming potential (GWP) is high. Therefore, alternative refrigerants\\u000a are needed as a replacement for R-134a. R-152a is

S.-Y. Yoo; D.-W. Lee

2009-01-01

70

Nearly Azeotropic Mixtures To Replace Refrigerant 12  

NASA Technical Reports Server (NTRS)

Number of nearly azeotropic fluid mixtures have saturation pressures similar to Refrigerant 12 while being about 2 percent as damaging to ozone layer. Five mixtures of R134a, R152a, R124, and R142b have low boiling-point spreads, low toxicity, and low ozone-damaging capability, are nonflammable, and more compatible with conventional oils than R134a. Pressure of combinations nearly equal to R12, and mixtures may be good "drop-in substitutes". Overall composition not altered by leakage. Usable in commercial, automotive, and household refrigerators and air conditioners.

Jones, Jack A.

1992-01-01

71

3He/ 4He dilution refrigerator with high cooling capacity and direct pulse tube pre-cooling  

NASA Astrophysics Data System (ADS)

In the article, a 3He/ 4He dilution refrigerator (DR) is described which is pre-cooled by a commercial two-stage pulse tube refrigerator (PTR); cryo-liquids are not necessary with this type of milli-kelvin refrigerator. The simple design of the condensation stage of this so-called dry DR is novel and explained in detail. In most dry DRs the circulating 3He gas is cooled by a two-stage PTR to a temperature of about 4 K. In the next cooling step, the 3He flow is cooled and partially liquefied in a Joule-Thomson circuit, before it is run to the dilution refrigeration unit. The counterflow heat exchanger of the Joule-Thomson circuit is cooled by the cold 3He gas pumped from the still of the DR. In the DR described here, the heat exchanger of the Joule-Thomson stage was omitted entirely; in the present design, the 3He gas is cooled by the PTR in three different heat exchangers, with the first one mounted on the first stage of the PTR, the second one on the regenerator of the second stage, and the third one on the cold end of the second stage. The heat load caused by the 3He flow is mostly absorbed by the first two heat exchangers. Thus the 3He flow presents only a small heat load to the second stage of the PTR, which therefore operates close to its base temperature of 2.5 K at all times. A pre-cooling temperature of 2.5 K of the 3He flow is sufficiently low to run a DR without further pre-cooling. The simplified condensation system allows for a shorter, compacter and more economical design of the DR. Additionally, the pumping speed of the turbo pump is no longer obstructed by the counterflow heat exchanger of the Joule Thomson stage as in our earlier DR design.

Uhlig, Kurt

2008-11-01

72

Optimizing the Low Temperature Cooling Energy Supply: Experimental Performance of an Absorption Chiller, a Compression Refrigeration Machine and Direct Cooling - a Comparison  

E-print Network

A strategy to optimize the low temperature cooling energy supply of a newly build office building is discussed against the background of a changing energy system. It is focused on, what production way - Direct Cooling, the Compression Refrigeration...

Uhrhan, S.; Gerber, A.

2012-01-01

73

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

74

Solutions for Liquid Nitrogen Pre-Cooling in Helium Refrigeration Cycles  

E-print Network

Pre-cooling of helium by means of liquid nitrogen is the oldest and one of the most common process features used in helium liquefiers and refrigerators. Its two principle tasks are to allow or increase the rate of pure liquefaction, and to permit the initial cool-down of large masses to about 80 K. Several arrangements for the pre-cooling process are possible depending on the desired application. Each arrangement has its proper advantages and drawbacks. The aim of this paper is to review the possible process solutions for liquid nitrogen pre-cooling and their particularities.

Wagner, U

2000-01-01

75

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

76

R-134a liquid over-feeding mobile air conditioning systems  

Microsoft Academic Search

For most air conditioning systems, usually only 85% of the evaporator is effectively used. The other 15% is used to superheat the refrigerant so that the compressor will be protected from liquid slugging, but this practice results in excessive evaporator volume. In mobile air conditioning (MAC) systems where the space available for the evaporator is very limited, the evaporator should

V. C. Mei; D. M. Kyle; F. C. Chen

1992-01-01

77

A robust platform cooled by superconducting electronic refrigerators  

NASA Astrophysics Data System (ADS)

A biased tunnel junction between a superconductor and a normal metal can cool the latter electrode. Based on a recently developed cooler with high power and superior performance, we have integrated it with a dielectric silicon nitride membrane, and cooled phonons from 305 mK down to 200 mK. Without perforation and covered under a thin alumina layer, the membrane is rigorously transformed into a cooling platform that is robust and versatile for multiple practical purposes. We discussed our results and possibilities to further improve the device.

Nguyen, H. Q.; Meschke, M.; Pekola, J. P.

2015-01-01

78

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...

79

Refrigerant flow characteristics of electronic expansion valve based on thermodynamic analysis and experiment  

Microsoft Academic Search

A mass flow correlation for R134a through an EEV (electronic expansion valve) is developed from extensive experimental data. The refrigerant mass flow characteristics of the EEV are an important issue in heat pump\\/refrigeration system operation because the valve regulates the refrigerant flow to match various operating conditions. Based on the throttling mechanism and thermodynamic analysis, the mass flow rate is

Xue Zhifang; Shi Lin; Ou Hongfei

2008-01-01

80

ARTI Refrigerant Database  

SciTech Connect

The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air- conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on R-32, R-123, R-124, R- 125, R-134a, R-141b, R142b, R-143a, R-152a, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses polyalkylene glycol (PAG), ester, and other lubricants. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits.

Calm, J.M.

1992-04-30

81

Closed-cycle refrigerator-cooled scanning SQUID microscope for room-temperature samples  

Microsoft Academic Search

We have designed, built, and operated a scanning superconducting quantum interference device (SQUID) microscope that uses a closed-cycle refrigerator to cool a YBa2Cu3O7 (YBCO) dc SQUID to 77 K. The SQUID is mounted in custom vacuum housing that has a thin sapphire window that maintains thermal isolation of the SQUID while allowing samples to be imaged in air at room

E. F. Fleet; S. Chatraphorn; F. C. Wellstood; L. A. Knauss; S. M. Green

2001-01-01

82

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

83

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] [Seoul National Univ. (Korea, Republic of). Dept. of Mechanical Engineering

1999-01-01

84

Thin Film Solid State Refrigerators for Spot Cooling of Integrated Ali Shakouri, Daryoosh Vashaee, James Christofferson, Xiaofeng Fan*, Chris Labounty*  

E-print Network

in a bulk manufacturing technology that is not compatible with IC processing. In addition the cooling powerThin Film Solid State Refrigerators for Spot Cooling of Integrated Circuits Ali Shakouri, Daryoosh-chip temperature of the packaged VLSI circuits not only can reach as high as 100C on average, but also can vary

85

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

SciTech Connect

The electrocaloric effect of BaTiO{sub 3} 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 [Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Key Laboratory of Environmental Fracture, University of Science and Technology Beijing, Ministry of Education, Beijing 100083 (China); Zheng Guangping; Shi Sanqiang [Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

2010-11-15

86

Refrigerator  

SciTech Connect

A refrigerator is described comprising: (a) a housing having a vent compartment and an insulated box having a cooler compartment and a freezer compartment; (b) a thermoelectric heat pump means mounted in the housing, the heat pump means including a finned heat sink of high temperature coefficient material mounted in the vent compartment. A hot plate is attached to the heat sink. A thermopile has a hot side connected to the hot plate and a cold side, a block of high temperature coefficient material is connected to the cold side. An L-shaped bracket of high temperature coefficient material having a vertical portion attached to the block and a horizontal portion extends into the freezer compartment. A freezer compartment of high temperature coefficient material has a bottom attached to the L-shaped horizontal portion. The bottom portion has walls forming an ice cube tray receiving recess whereby the continuous structure of high temperature coefficient material exists between the thermopile and ice cube tray receiving recess to produce a sub freezing temperature in the recess; and (c) an ice cube tray having a shape corresponding to that of the ice cube tray receiving recess whereby five sides of the ice cube tray are in freezing engagement with the bottom recess forming walls for freezing ice cubes.

Burke, E.J.

1987-02-24

87

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

NASA Technical Reports Server (NTRS)

A report describes a pulse tube refrigerator that uses a mixture of He-3 and superfluid He-4 to cool to temperatures below 300 mK, while rejecting heat at temperatures up to 1.7 K. The refrigerator is driven by a novel thermodynamically reversible pump that is capable of pumping the He-3 He-4 mixture without the need for moving parts. The refrigerator consists of a reversible thermal magnetic pump module, two warm heat exchangers, a recuperative heat exchanger, two cold heat exchangers, two pulse tubes, and an orifice. It is two superfluid pulse tubes that run 180 out of phase. All components of this machine except the reversible thermal pump have been demonstrated at least as proof-of-concept physical models in previous superfluid Stirling cycle machines. The pump consists of two canisters packed with pieces of gadolinium gallium garnet (GGG). The canisters are connected by a superleak (a porous piece of VYCOR glass). A superconducting magnetic coil surrounds each of the canisters.

Miller, Franklin K.

2012-01-01

88

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

89

The natural fluid nitrous oxide—an option as substitute for low temperature synthetic refrigerants  

Microsoft Academic Search

A theoretical investigation was performed concerning the coefficient of performance (COP) of cascade refrigerating systems using N2O as refrigerant for the low temperature cascade stage and various natural refrigerants like ammonia, propane, propene, carbon dioxide and nitrous oxide itself for the high temperature stage. The basis of the comparison was a conventional R23\\/R134a-cascade refrigerating system for heat rejection temperatures of

H. Kruse; H. Rüssmann

2006-01-01

90

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

91

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

92

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

SciTech Connect

The design of the Lorenz-Meutzner refrigerator/freezer has two evaporators (located in the freezer and fresh food compartments), which makes it a leading candidate for use of zeotropic refrigerant mixtures. Zeotropic mixtures can have significant temperature glides during evaporation and condensation. Performance of the zeotropic mixture can be maximized in the LM design by permitting the lower end of the temperature glide to occur in the freezer compartment evaporator and the higher end in the fresh food compartment evaporator. Several hydrofluoropropane-based zeotropes (e.g., R-227 ea/R-245ca) have been shown through steady-state modeling to outperform R-134a by up to 15%. Results from previous testing of this refrigerator/freezer using R-32/R-124 (zeotropic mixture) were published in an ASHRAE paper (Sand et al. 1993). Their results showed performance gains of approximately 3% over R-12. In the study presented in this paper, the Lorenz-Meutzner refrigerator/freezer having two evaporators and two intercoolers was experimentally tested in an environmental chamber according to Association of Home Appliance Manufacturers/Department of Energy (AHAM/DOE) testing standards using several hydrofluoropropane-based zeotropic mixtures. The results are compared to baseline testing with R-134a. The R-245ca/R-134a and R-245ca/R-152a mixtures performed comparably to R-134a. R-245ca/R-270 outperformed all zeotropic mixtures and R-134a by at least 16%. Also, a refrigerant sampling loop is added to determine the running composition of the mixture and its effects on the performance of the refrigerator/freezer.

Baskin, E. [Environmental Protection Agency, Research Triangle Park, NC (United States); Bayoglu, E.S.; Delafield, F.R. [Acurex Environmental Corp., Durham, NC (United States)

1997-12-31

93

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

94

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 Chiriac; Tien-Yu Tom Lee

2001-01-01

95

Evaluation of performance and composition shift of zeotropic mixtures in a Lorenz-Meutzner refrigerator/freezer  

SciTech Connect

Results from previous testing of this refrigerator/freezer using a 750 Btu/h compressor and several zeotropic mixtures revealed a performance enhancement up to 16% above that of hydrofluorocarbon R-134a. In the study presented in this paper, the Lorenz-Meutzner (LM) refrigerator/freezer equipped with a 1060 Btu/h compressor, two evaporators, and two intercoolers was experimentally tested in an environmental chamber according to the Association of Home Appliance Manufacturers/Department of Energy (AHAM/DOE) testing standards using several hydrofluoropropane-based zeotropic mixtures. The results are compared to baseline testing with R-134a and results obtained using the 750 Btu/h compressor. Hydrofluorocarbons R-245ca/R-152a performed comparably to R-134a. R-245ca/hydrocarbon R-270 (cyclopropane C{sub 3}H{sub 6}) outperformed all zeotropic mixtures and R-134a by at least 12.2 {+-} 0.7%. All refrigerants performed better using the larger compressor due to its inherently better efficiency. Refrigerant samples taken during refrigerator/freezer operation revealed substantial composition shifts (e.g., a 30% running composition shift of R-134a in the R-245ca/R-134a mixture). Sand et al. (1993) obtained an approximately 20% energy reduction using steady-state on-cycle energy consumption results; a comparison was made between chlorofluorocarbon R-12 and a hydrofluorocarbon R-32/hydrochlorofluorocarbon R-124 mixture. Lorenz and Meutzner (1975), originators of the Lorenz-Meutzner refrigerator/freezer design, state that the following parameters influence the optimum performance of the design: (1) heat exchanger size, (2) capillary tube length, (3) refrigerant charge, and (4) compressor size. This work investigates three of these parameters--capillary tube length, compressor size, and refrigerant charge.

Baskin, E.; Smith, N.D.; Delafield, F.R.; Tufts, M.W.

1999-07-01

96

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

97

Cooling Power Density of SiGe/Si Superlattice Micro Refrigerators Gehong Zeng, Xiaofeng Fan, Chris LaBounty, Edward Croke2  

E-print Network

Cooling Power Density of SiGe/Si Superlattice Micro Refrigerators Gehong Zeng, Xiaofeng Fan, Chris Experiments were carried out to determine the cooling power density of SiGe/Si superlattice microcoolers by integrating thin film metal resistor heaters on the cooling surface. By evaluating the maximum cooling

Bowers, John

98

Thermotile Refrigerators  

NASA Technical Reports Server (NTRS)

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

Park, Brian V.

1994-01-01

99

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

100

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

101

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

102

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

103

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

Microsoft Academic Search

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:

J. Pannock; D. A. Didion

1991-01-01

104

Chemical and thermal stability of refrigerant-lubricant mixtures with metals  

SciTech Connect

This report presents completed sealed tube stability test results for the following eight refrigerant/lubricant mixtures: R-22/mineral oil; R-124/alkylbenzene; R-134a/pentaerythritol (PE) ester (mixed acid); R- 134a/PE (branched acid); R-134a/ PE (100 cSt viscosity); R- 142b/alkylbenzene; R-143a/ PE (branched acid); R-152a/alkylbenzene. Partial results are shown for an additional eight refrigerant-lubricant mixtures. Though work is in progress, no data are available at this point in time for the five remaining test mixtures. Reported are: visual observations on aged sealed tubes, gas chromatographic analyses on the vapor phase contents of the tubes, chloride ion contents of HCFC containing mixtures or fluoride ion contents of HFC mixtures, and total acid number values and infrared analysis results for mixtures containing ester lubricants.

Huttenlocher, D.F.

1992-07-10

105

In-tube heat transfer and pressure drop of R-134a and ester lubricant mixtures in a smooth tube and a micro-fin tube. Part 1: Evaporation  

SciTech Connect

In-tube heat transfer coefficients and pressure drops during evaporation are reported for mixtures of refrigerant R-134a and a penta erythritol ester mixed-acid lubricant. The ester lubricant was tested at viscosities of 169 SUS and 369 SUS over a lubricant concentration range of 0% to 5% in both a smooth tube and a micro-fine tube. The average saturation temperature used was 1 C (33.8 F). Measurements were taken for the refrigerant-lubricant mixture over a mass flux range of 85 kg/m{sup 2}{center_dot}s (62,700 lb/ft{sup 2}{center_dot}h) to 375 kg/m{sup 2}{center_dot}s (276,640 lb/ft{sup 2}{center_dot}h) in test tubes with an outer diameter of 9.52 mm (3/8 in.). Heat transfer coefficients during evaporation increased at low concentrations of the 169-SUS ester lubricant and then dropped off at high lubricant concentrations in both the smooth tube and the micro-fin tube. The higher viscosity 369-SUS lubricant decreased the heat transfer coefficients in both tubes over the range of lubricant concentrations tested. Pressure drops during evaporation increased in both the smooth tube and the micro-fin tube with the addition of ester lubricant of either viscosity. The heat transfer coefficients for the micro-fin tube were 100% to 50% higher than those for the smooth tube, with the higher values occurring at low mass fluxes. Pressure drops in the micro-fin tube were 10% to 20% higher than those in the smooth tube.

Eckels, S.J. [Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering; Doerr, T.M.; Pate, M.B. [Iowa State Univ., Ames, IA (United States). Dept. of Mechanical Engineering

1994-12-31

106

System performance characteristics of a helical rotary screw air-cooled chiller operating over a range of refrigerant charge conditions  

SciTech Connect

This paper presents a study involving the operation of a 70-ton helical rotary, dual-circuit, air-cooled chiller while three independent variables are experimentally altered. The independent variables included in the study are refrigerant charge level within the chiller plant, outdoor air temperature, and percentage nominal chiller load. This paper examines the effects of the three independent variables on superheat and subcooling temperatures, chiller kW per ton, chilled water set-point temperature control, and compressor suction and discharge pressures. After analyzing the significance of refrigerant charge, outdoor air temperature, and percentage nominal chiller load on the operation of a chiller plant the consequences of refrigerant undercharge or overcharge are fully investigated and documented. All experimental testing was conducted in a full-scale heating, ventilation, and air-conditioning (HVAC) laboratory using a realistic load profile and actual outdoor air temperature conditions. Experimental testing began with an evacuation, recycle, and recharge of R-22 from both circuits of the chiller. The charge tests included holding the refrigerant charge in circuit No. 2 constant at the manufacturer`s recommended level. The notation adopted for the manufacturer`s recommended charge or nominal charge level was 0% charge. Circuit No. 1`s refrigerant charge was varied from {minus}60% to +15% of nominal charge in 5% increments.

Bailey, M.B. [Military Academy, West Point, NY (United States). Civil and Mechanical Engineering Dept.

1998-12-31

107

Module Development and Simulation of the Variable Refrigerant Flow Air Conditioning System under Cooling Conditions in Energyplus  

E-print Network

ICEBO2006, Shenzhen, China HVAC Technologies for Energy Efficiency Vol.IV-1-2 Module Development and Simulation of the Variable Refrigerant Flow Air Conditioning System under Cooling Conditions in Energyplus Yanping Zhou Jingyi... Wu Ruzhu Wang Sumio Shiochi Ph.D student Professor Professor Chief Researcher Shanghai Jiaotong Univ. Shanghai Jiaotong Univ. Shanghai Jiaotong Univ. DAKIN Air-conditioning, Ltd Shanghai, China Shanghai, China Shanghai, China Osaka...

Zhou, Y.; Wu, J.; Wang, R.; Shiochi, S.

2006-01-01

108

The LSST Camera 500 watt -130 degC Mixed Refrigerant Cooling System  

SciTech Connect

The LSST Camera has a higher cryogenic heat load than previous CCD telescope cameras due to its large size (634 mm diameter focal plane, 3.2 Giga pixels) and its close coupled front-end electronics operating at low temperature inside the cryostat. Various refrigeration technologies are considered for this telescope/camera environment. MMR-Technology’s Mixed Refrigerant technology was chosen. A collaboration with that company was started in 2009. The system, based on a cluster of Joule-Thomson refrigerators running a special blend of mixed refrigerants is described. Both the advantages and problems of applying this technology to telescope camera refrigeration are discussed. Test results from a prototype refrigerator running in a realistic telescope configuration are reported. Current and future stages of the development program are described. (auth)

Bowden, Gordon B.; Langton, Brian J.; Little, William A.; Powers, Jacob R; Schindler, Rafe H.; Spektor, Sam; /MMR-Technologies, Mountain View, CA

2014-05-28

109

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

110

ARTI Refrigerant Database  

SciTech Connect

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

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

1993-04-30

111

Literature survey on thermophysical properties of refrigerants  

SciTech Connect

A bibliographic compilation is given on thermophysical properties of the environmentally acceptable hydrofluorocarbon blends R404A, R407C, and R410A. These refrigerant blends are still under investigation and meant to replace the transitional hydrochlorofluorocarbon R22 and the azeotrope R502. In a second part reliable formulations to calculate thermophysical-property surfaces of some selected well investigated fluids used in refrigeration are recommended. The fluids water, air, carbon dioxide, ammonia, R134a, R123, and R152a are subjects of that part.

Krauss, R.; Stephan, K. [Univ. Stuttgart (Germany). Inst. fuer Technische Thermodynamik and Thermische Verfahrenstechnik

1998-11-01

112

Literature Survey on Thermophysical Properties of Refrigerants  

NASA Astrophysics Data System (ADS)

A bibliographic compilation is given on thermophysical properties of the environmentally acceptable hydrofluorocarbon blends R404A, R407C, and R410A. These refrigerant blends are still under investigation and meant to replace the transitional hydrochlorofluorocarbon R22 and the azeotrope R502. In a second part reliable formulations to calculate thermophysical-property surfaces of some selected well investigated fluids used in refrigeration are recommended. The fluids water, air, carbon dioxide, ammonia, R134a, R123, and R152a are subjects of that part.

Krauss, R.; Stephan, K.

1998-11-01

113

Chemical and thermal stability of refrigerant-lubricant mixtures with metals. Quarterly report, 1 April 1992--30 June 1992  

SciTech Connect

This report presents completed sealed tube stability test results for the following eight refrigerant/lubricant mixtures: R-22/mineral oil; R-124/alkylbenzene; R-134a/pentaerythritol (PE) ester (mixed acid); R- 134a/PE (branched acid); R-134a/ PE (100 cSt viscosity); R- 142b/alkylbenzene; R-143a/ PE (branched acid); R-152a/alkylbenzene. Partial results are shown for an additional eight refrigerant-lubricant mixtures. Though work is in progress, no data are available at this point in time for the five remaining test mixtures. Reported are: visual observations on aged sealed tubes, gas chromatographic analyses on the vapor phase contents of the tubes, chloride ion contents of HCFC containing mixtures or fluoride ion contents of HFC mixtures, and total acid number values and infrared analysis results for mixtures containing ester lubricants.

Huttenlocher, D.F.

1992-07-10

114

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

115

Heat transfer coefficients and pressure drops for R-134a and an ester lubricant mixture in a smooth tube and a micro-fin tube  

SciTech Connect

This paper reports average heat transfer coefficients and pressure drops during the evaporation and condensation of mixtures of R-134a and a 150 SUS penta erythritol ester branched-acid lubricant. The smooth tube and micro-fin tube tested in this study had outer diameters of 9.52 mm (3/8 in.). The micro-fin tube had 60 fins, a fin height of 0.2 mm (0.008 in), and a spiral angle of 18{degree}. The objective of this study is to evaluate the effectiveness of the micro-fin tube with R-134a and to determine the effect of circulating lubricant. The experimental results show that the micro-fin tube has distinct performance advantages over the smooth tube. For example, the average heat transfer coefficients during evaporation and condensation in the micro-fin tube were 50--200% higher than those for the smooth tube, while the average pressure drops were on average only 10--50% higher. The experimental results indicate that the presence of a lubricant degrades the average heat transfer coefficients during both evaporation and condensation at high lubricant concentrations. Pressure drops during evaporation increased with the addition of a lubricant in both tubes. For condensation, pressure drops were unaffected by the addition of a lubricant.

Eckels, S.J. [Kansas State Univ., Manhattan, KS (United States); Doerr, T.M.; Pate, M.B. [Iowa State Univ., Ames, IA (United States). Mechanical Engineering Dept.

1998-10-01

116

A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes  

SciTech Connect

The average heat transfer coefficients and pressure drops during evaporation and condensation are reported for mixtures of R-134a and an ester lubricant in tubes of 12.7 mm (1/2 in.) outer diameter. The objective of this paper is to evaluate the performance of the R-134a-lubricant mixtures in these tubes and determine the performance benefits of the micro-fin tube. The performance benefits of the tubes with 12.7 mm (1/2 in.) outer diameter are compared to those of smaller tubes with 9.52 mm (3/8 in.) outer diameter. The lubricant used was a 169 SUS penta erythritol ester mixed-acid lubricant. The lubricant concentration was varied from 0--5.1% in the mixture. The average heat transfer coefficients in the 12.7 mm (1/2 in.) micro-fin tube were 50--150% higher than those for the 12.7 mm (1/2 in.) smooth tube, while pressure drops in the micro-fin tube were 5% to 50% higher than in the smooth tube. The addition of lubricant degraded the average heat transfer coefficients in all cases except during evaporation at low lubricant concentrations. Pressure drops were always increased with the addition of lubricant. The experimental results also indicate that tube diameter has some effect on the performance benefits of the micro-fin tube over that of the smooth tube.

Eckels, S.J. [Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering; Doerr, T.M.; Pate, M.B. [Iowa State Univ., Ames, IA (United States). Mechanical Engineering Dept.

1998-10-01

117

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

118

Refrigeration for Cryogenic Sensors  

NASA Technical Reports Server (NTRS)

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

Gasser, M. G. (editor)

1983-01-01

119

page 1 of 4 TkF Vrmeteknik Refrigeration / Kylteknik  

E-print Network

with methylchloride (CH3Cl, R-40) as refrigerant. The evaporator operates at Te = -20 °C and exchanges heat kJ/kg. a. Calculate the heat of vaporisation of the R-40 at 30°C and -20°C, and calculate-134a are measured to be +20°C, 4.0 bar. a. What is the vapour/liquid state of the R-134a; is it 1

Zevenhoven, Ron

120

Economic analysis of wind-powered refrigeration cooling/water-heating systems in food processing. Final report  

SciTech Connect

Potential applications of wind energy include not only large central turbines that can be utilized by utilities, but also dispersed systems for farms and other applications. The US Departments of Energy (DOE) and Agriculture (USDA) currently are establishing the feasibility of wind energy use in applications where the energy can be used as available, or stored in a simple form. These applications include production of hot water for rural sanitation, heating and cooling of rural structures and products, drying agricultural products, and irrigation. This study, funded by USDA, analyzed the economic feasibility of wind power in refrigeration cooling and water heating systems in food processing plants. Types of plants included were meat and poultry, dairy, fruit and vegetable, and aquaculture.

Garling, W.S.; Harper, M.R.; Merchant-Geuder, L.; Welch, M.

1980-03-01

121

Performance of HCFC22 alternative refrigerants  

SciTech Connect

In this study, 14 refrigerant mixtures composed of R32, R125, R134a, R152a, R290(Propane) and R1270(Propylene) were tested in a breadboard heat pump in an attempt to replace R22 used in residential air-conditioners. The test heat pump was of 1 ton capacity with water as the secondary heat transfer fluids. All tests were conducted under ARI test A condition. Test results how that ternary mixtures composed of R32, R125, and R134a have 4 {approximately} 5% higher coefficient of performance(COP) and capacity than R22. Hence they seem to be promising alternatives for R22. On the other hand, ternary mixtures containing R125, R134a, and R152a have lower COPs and capacities than R22. R290/R134 azeotrope also shows 3--4% increases in COP and capacity. The compressor discharge and dome temperatures of all the mixtures tested are lower than those of R22 by 15.9--34.7 C and 5.5--14.3 C respectively, indicating that these mixtures would offer better system reliability and longer life time than R22. Finally, the test results with a suction line heat exchanger (SLHX) indicated that SLHX must be used with special care in air-conditioners since its effect is fluid dependent.

Jung, D.; Kim, C.B.; Song, Y.J.; Park, B.J.

1999-07-01

122

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

123

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

124

Saturated liquid viscosity correlations for alternative refrigerants  

NASA Astrophysics Data System (ADS)

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 ?{n/D} = A + BT, where ?D is the dimensionless fluidity (l ?D) and T 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 D=0.8.

Khan, S.; Srinivasan, K.

1996-03-01

125

Investigation of the Influence of Cooling Water Inlet Temperature on Characteristics and Ammonia Charging Quantity of Ammonia-Water Absorption Refrigerator  

NASA Astrophysics Data System (ADS)

For purposes such as freezing and ice accumulation which require temperatures below 0 degrees, ammonia-water absorption refrigerator is being looked at once again. If used for these purpose, it is usually driven all through the year. In this case, cooling water inlet temperature which greatly influences absorption cycle changes very widely. So in such conditions, it is hoped to be driven high efficiently. And ammonia's charging quantity is required as small as possible on account of poisonous. But when it driven all through the year, ammonia charging quantity influences the efficiency greatly. So this research aims to clarify the ammonia charging quantity with which ammonia-water absorption refrigerator can be driven high efficiently. So static simulation model was made. By using this tool, we investigated the influence of cooling water inlet temperature on COP, solution concentration. As a result, minimum ammonia charging quantity with which ammonia water absorption refrigerator can be driven was obtained.

Takei, Toshitaka; Saito, Kiyoshi; Kawai, Sunao

126

Laser cooling of a semiconductor by 40 kelvin: an optical refrigerator based on cadmium sulfide nanoribbions  

NASA Astrophysics Data System (ADS)

We have demonstrated the first net laser cooling of semiconductors using CdS nanoribbons (or nanobelts) in this work. This net cooling effect is found to be facilitated by resonant high order annihilation of longitudinal optical (LO) phonons due to a strong exciton-LO phonon Fröhlich interactions. Using a pumpprobe luminescence thermometry technique to measure the local temperature change, we have achieved as large as 40 K cooling temperature from room temperature pumped by a 514 nm laser while a 532 nm laser pumping led to a cooling of 20 K. At 100 K, only the 532 nm laser pumping can lead to a net cooling of around 15 K. Our work opens new directions to search laser cooling semiconductors and makes it feasible to achieve all solid-state cryocoolers based on semiconductors.

Zhang, Jun; Li, Dehui; Chen, Renjie; Xiong, Qihua

2013-03-01

127

Supercooling Refrigerator  

NASA Technical Reports Server (NTRS)

A Goddard/Philips research project resulted in a refrigeration system which works without seals, lubricants or bearings. The system, originally developed to cool satellite-based scientific instruments, has an extensive range of potential spinoffs. It is called the Stirling Cycle Cryogenic Cooler and eliminates friction by using electronically controlled linear magnetic bearings. Mechanical failure, contamination are eliminated.

1986-01-01

128

Dual mixed refrigerant natural gas liquefaction with staged compression  

Microsoft Academic Search

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

1985-01-01

129

The vapor compression refrigeration cycle  

Microsoft Academic Search

This article is a review of the basic principles of a cycle widely used to create the refrigeration effect that provides both human comfort and process cooling. While a semantic differentiation often is made for cooling and dehumidifying air for human comfort (air conditioning) and cooling for products and processes (refrigeration), all mechanical cooling applications depend on the previously mentioned

Pannkoke

1995-01-01

130

High efficiency, high capacity cooling and refrigeration. Semi-annual report for the period May-October 1999  

SciTech Connect

Tasks 1 through 3 (identify candidate refrigerants, construct bench-top test device, test candidate refrigerants in the bench-top device) are complete. The project is on budget and on schedule. Significant positive results have been obtained.

McCullough, Edward T.; Dhooge, Patrick M.; Nimitz, J. S.

1999-10-01

131

Energy Efficiency Evaluation of Refrigeration Technologies in Combined Cooling, Heating and Power Systems  

E-print Network

. Performance parameters for five types of chillers Chiller type Rated cold energy?kW ? COP Chiller auxiliary power?kW ? Double-effect steam?8bar ? 1740 1.35 5.25 single-effect steam?1bar ? 1740 0.75 5.25 Double-effect flue gas 1740 1.35 5... comparison between five types chillers water pump, cooling water pump and fan of cooling tower. Exergy efficiency of five types chillers considering auxiliary equipment power consumption is also shown in figure 2. 0.0 0.1 0.2 0.3 0.4 0.5 double...

Zuo, Z.; Hu, W.

2006-01-01

132

A Dynamic Model of a Vapor Compression Refrigeration Cycle using Zeotropic Refrigerant Mixtures  

NASA Astrophysics Data System (ADS)

In order to prove the effectiveness of the developed model, reported in the first report, about dynamics of a vapor compression refrigeration cycle with zeotropic refrigerant mixtures, simulation results are compared with the experimental results obtained for R-407C (R-32/R-125/R-134a=23/25/52wt%).The simulation results are consistent well with the experimental results. As a result of the numerical analysis of dynamic characteristics of composition changing, the variation of compositions in the refrigeration cycle is caused by the variation of the existing compositions of accumulator. The time constant of the composition is approximately equal to the time constant of the pressure and the mass distribution.

Unezaki, Fumitake; Matsuoka, Fumio

133

Efficiency of vapor compression heat pumps based on non-azeotropic refrigerant mixtures  

NASA Astrophysics Data System (ADS)

The work presents the results of cycle computation for vapor compression pumps based on ozone-safe mixed refrigerants. Non-azeotropic binary refrugerants R32/R152a (30/70) and R32/R134a (30/70) were considere as working substances. Properties of non-azeotropic refrigerants were calculated according to the additivity method of thermodynamic functions and method of Lemmon and Jacobsen. Deviations in the values of thermophysical properties obtained with two methods have been determined. It is shown that at the use of nonazeotropic mixture R32/R152a (30/70), energy conversion ratio increases by 2.2-3.6 % compared with the results for R32/R134a (30/70) at temperature difference between the processes of boiling and condensation from 28 to 53 °C.

Mezentseva, N. N.

2011-06-01

134

Robust control of Propane Pre-cooled mixed refrigerant process for natural gas liquefaction  

Microsoft Academic Search

Natural Gas are often found at remote locations to bring it to the world market liquefaction is required. In liquefaction natural gas is cooled to around -160°C, hence required considerable amount of energy. To maximize the profit from the existing design it is necessary that the process should operate efficiently, reliably and safely. Hence a good and Robust control is

Mohd Shariq Khan; Mun Kyu Yoon; Yuli Amalia Husnil; Moonyong Lee

2010-01-01

135

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

136

Prospect of hydrocarbon uses based on exergy analysis in the vapor compression refrigeration system  

Microsoft Academic Search

om Abstract-This paper emphasized on the possibilities of researches in the field of exergy analysis in various usable sectors where vapor compression refrigeration systems are used. Exergy losses, exergy efficiency, second law efficiency and irreversibility of the system components as well as of the whole system are measured. In the vapor compression system, R134a, R290 and R600a are considered as

J. U. Ahamed; R. Saidur; H. H. Masjukil

2011-01-01

137

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

138

Prediction of Heat Transfer Characteristics of Binary Refrigerant Mixtures in a Plate-Fin Condenser  

NASA Astrophysics Data System (ADS)

The heat transfer characteristics of binary refrigerant mixtures in a plate-fin condenser are experimentally investigated using a vapor compression heat transformer, in which binary refrigerant mixtures of R 134a/ R 123 are used as the working fluid and water is used as both heat sink and source. Pure refrigerants of R 22 and R 134a are also tested as the working fluid. The experimental ranges of heat flux and mass velocity are from 2 to 20 kW/m2 and from 50 to 100 kg/m2s, respectively. The heat transfer characteristics of the condensation and vapor single-phase flow of pure and mixed refrigerants are discussed, and empirical correlation equations of the condensate heat transfer and vapor single-phase heat transfer are proposed. The correlation equation of water-side heat transfer is also presented. Combining these correlation equations with a correlation equation of vapor mass transfer based on the Chilton-Colburn analogy, a prediction model for condensation of the binary refrigerant mixtures in a plate-fin heat exchanger is developed based on the assumption that the phase equilibrium is only established at the vapor-liquid interface. The calculation results for the pure and mixed refrigerants agree well with the present experimental data. The mass transfer characteristics are also revealed from the calculation results.

Yara, Tomoyasu; Koyama, Shigeru

139

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

140

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

141

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

142

Waste heat driven absorption\\/vapor-compression cascade refrigeration system for megawatt scale, high-flux, low-temperature cooling  

Microsoft Academic Search

A novel cascaded absorption\\/vapor-compression cycle with a high temperature lift for a naval ship application was conceptualized and analyzed. A single-effect LiBr–H2O absorption cycle and a subcritical CO2 vapor-compression cycle were coupled together to provide low-temperature refrigerant (?40°C) for high heat flux electronics applications, medium-temperature refrigerant (5°C) for space conditioning and other low heat flux applications, and as an auxiliary

Srinivas Garimella; Ashlie M. Brown; Ananda Krishna Nagavarapu

2011-01-01

143

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

144

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

145

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

146

Simulation and economic optimization of a solar assisted combined ejector–vapor compression cycle for cooling applications  

Microsoft Academic Search

This paper describes the hourly simulation and optimization of a thermally driven cooling cycle assisted by solar energy. The double stage solar ejector cooling cycle is modelled using the TRNSYS-EES simulation tool and the typical meteorological year file containing the weather data of Florianópolis, Brazil. The first stage is performed by a mechanical compression system with R134a as the working

Humberto Vidal; Sergio Colle

2010-01-01

147

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

148

Thermodynamic evaluation of five alternative refrigerants in vapor-compression cycles  

SciTech Connect

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 should be applied in a cycle without internal heat exchange. The second alternative is R134a, which should be applied in a cycle with internal heat exchange. Between R143a and R125, both of which should be applied in a cycle with internal heat exchange, the better replacement thermodynamically for R502 is R143a, particularly at high condensing temperatures. At low condensing temperatures, R125 is to be considered, especially if extended internal heat exchange is applied. As a replacement for R502, R32 has good performance and much higher volumetric capacity. However, excessively high discharge temperatures contraindicate its use, particularly with hermetic and semi-hermetic compressors. No internal heat exchange should be applied with R32, and extreme care should be taken to prevent superheating in suction lines.

Kazachki, G.S.; Gage, C.L.

1991-01-01

149

Toxicity Data to Determine Refrigerant Concentration Limits  

SciTech Connect

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

Calm, James M.

2000-09-30

150

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

151

Use of hypometabolic TRIS extenders and high cooling rate refrigeration for cryopreservation of stallion sperm: Presence and sensitivity of 5' AMP-activated protein kinase (AMPK).  

PubMed

This study evaluated the effect of the use of hypometabolic TRIS extenders in the presence or the absence of AMPK activators as well as the utilization of high cooling rates in the refrigeration step on the freezability of stallion sperm. Twelve ejaculates were cryopreserved using Botucrio® as a control extender and a basic TRIS extender (HM-0) separately supplemented with 10mM metformin, 2mM 5-aminoimidazole-4-carboxamide-1-?-d-ribofuranoside (AICAR), 2mM Adenosine monophosphate (AMP), 40?M compound C AMPK inhibitor or 2mM AMP+40?M compound C. Our results showed that the utilization of a hypometabolic TRIS extender supplemented or not with AMP or metformin significantly improves stallion sperm freezability when compared with a commercial extender. Additionally, high cooling rates do not affect stallion sperm quality after cooling and post-thawing. Finally, stallion spermatozoa present several putative AMPK sperm isoforms that do not seem to respond to classical activators, but do respond to the Compound C inhibitor. PMID:25445464

Córdova, Alex; Strobel, Pablo; Vallejo, Andrés; Valenzuela, Pamela; Ulloa, Omar; Burgos, Rafael A; Menarim, Bruno; Rodríguez-Gil, Joan Enric; Ratto, Marcelo; Ramírez-Reveco, Alfredo

2014-12-01

152

Development of a low-temperature germanium detector via mechanical cooling with a compact pulse-tube refrigerator  

NASA Astrophysics Data System (ADS)

We have developed a new germanium (Ge) detector unit for hypernuclear ?-ray spectroscopy at J-PARC, which comprises a new Ge detector array Hyperball-J. A compact pulse-tube refrigerator is coupled to a coaxial Ge detector in order to achieve lower crystal temperatures as a means to increase radiation hardness. The obtained crystal temperature is 72 K, while an energy resolution is maintained at (FWHM) 3.1(1) keV for 1.33 MeV ? rays using a gate-integrated shaping amplifier (ORTEC 973U). Gain shifts with changing crystal temperature are also confirmed for the Ge detector.

Koike, T.; Chiga, N.; Haruyama, T.; Hosomi, K.; Ichinohe, H.; Kasami, K.; Matsushita, T.; Mizoguchi, Y.; Ono, H.; Shirotori, K.; Takeuchi, T.; Tamura, H.; Yamamoto, T. O.

2015-01-01

153

Alternative refrigerants and refrigeration cycles for domestic refrigerators  

SciTech Connect

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

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

1992-12-01

154

Ideal orifice pulse tube refrigerator performance  

NASA Technical Reports Server (NTRS)

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

Kittel, P.

1992-01-01

155

Ideal orifice pulse tube refrigerator performance  

Microsoft Academic Search

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

P. Kittel

1992-01-01

156

Miniature thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

A miniature thermoacoustic refrigerator was developed for cooling electronic components. The refrigerator is driven at 5,000 Hz by a piezoelectric driver and it consists of an acoustic resonator, a stack, and copper heat exchangers. The working fluid is pressurized helium gas between 10 to 20 atmospheres. Sound was produced with different piezoelectric drivers, a monomorph, a bimorph, and Tonpilz driver to achieve the highest intensity possible. Since the operating frequency is high, the refrigerator is compact, being about 10 cm long. Temperature differences of 12 C across the stack were achieved at sound levels of 160 dB. The performance of the refrigerator scaled with frequency according to existing models of thermoacoustic heat engines.

Symko, Orest G.

1994-04-01

157

NICE3: Industrial Refrigeration System  

SciTech Connect

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

Simon, P.

1999-09-29

158

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

159

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

160

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

161

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

2013-12-01

162

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

163

Thermoacoustic refrigeration  

NASA Technical Reports Server (NTRS)

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

Garrett, Steven L.; Hofler, Thomas J.

1991-01-01

164

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

165

Malone refrigeration  

NASA Astrophysics Data System (ADS)

Malone refrigeration is the use of a liquid near its critical point, without evaporation, as the working fluid in a refrigeration cycle such as the Stirling cycle. We discuss relevant properties of appropriate liquids, and we describe two Malone refrigerators. The first, which was completed several years ago, established the basic principles of use for liquids in such cycles. The second, now under construction, is a linear, free-piston machine.

Swift, G. W.

166

Refrigerant charge management in a heat pump water heater  

DOEpatents

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

Chen, Jie; Hampton, Justin W.

2014-06-24

167

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

168

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

169

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

NASA Astrophysics Data System (ADS)

The study of several hydrofluorocarbons (HFC) and fluorocarbons (FC) and their binary mixtures that have no ozone-depleting ability is being carried Out in the framework of Belarus National Program. The fluids include HFCs R134a. R152a, R135, and R32, and FC R218. The following properties are being investigated: ( I ) phase equilibrium parameters including the boiling and condensing curve and 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.; Zhelezny, V. P.; Klepatsky, P. M.; Beljajeva, O. V.; Chernjak, Yu. A.; Kotelevsky, Yu. G.; Timofejev, B. D.

1996-05-01

170

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

171

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

172

Measured Effects of Retrofits - A Refrigerant Oil Additive and a Condenser Spray Device - On the Cooling Performance of a Heat Pump  

E-print Network

steady-state EER increase of 17%. Suction and discharge pressures were reduced by 7 and 37 psi, respectively. A refrigerant oil additive formulated to enhance refrigerant-side heat transfer was added at a dose of one ounce per ton of rated capacity...

Levins, W. P.; Sand, J. R.; Baxter, V. D.; Linkous, R. S.

1996-01-01

173

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

174

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

175

Current Information on the Properties of Hydrofluorocarbons(HFCs) and Other Pure Refrigerants  

NASA Astrophysics Data System (ADS)

In 1994, the JSRAE published 'HFCs and HCFCs', JAR Thermodynamic Tables, Vol.1, Version 1.0, providing the thermodynamic properties of 12 refrigerants with the software. At the time, experimental data for new alternative refrigerants were qualitatively and quantitatively limited. Many reliable experimental and theoretical information have been accumulated till present for pure HFCs. The ideal gas heat capacity values with an uncertainty of ±0.2 % and the transport properties are the good examples. New international standards on the molar gas constant or molar masses were defined very recently. As a review paper on the properties of HFCs, simple equations of the ideal-gas heat capacity, vapor pressures, saturated-liquid density, virial coefficients, surface tension, viscosity, thermal conductivity, and the information on the material compatibility and solubility with lubricants are summarized mainly for R32, R125, R134a, R143a, and R152a.

Sato, Haruki; Takaishi, Yoshinori; Kagawa, Noboru; Yokoyama, Chiaki; Higashi, Yukihiro; Fujii, Kenichi; Murakami, Kazuhiko; Assael, Marc J.; Noguchi, Masahiro; Tanabe, Hirone; Fukushima, Masato; Takigawa, Katsuya

176

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

177

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

178

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

179

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

2012-12-01

180

Kylteknik ("KYL")Kylteknik ("KYL") RefrigerationRefrigerationRefrigerationRefrigeration  

E-print Network

; Gas processing (O2, H2, CO2, LPG, LNG...) (3) Air conditioning, cooling towers, rg/pages/zon Air conditioning, cooling towers, food cooling and freezing (4) Heat pumps, heat pipes, special ww.sgisland.o p p

Zevenhoven, Ron

181

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

182

Application of magnetic refrigeration and its assessment  

NASA Astrophysics Data System (ADS)

Magnetic refrigeration has the potential to replace conventional refrigeration—with often problematic refrigerants—in several niche markets or even some main markets of the refrigeration domain. Based on this insight, for the Swiss Federal Office of Energy a list of almost all existing refrigeration technologies was worked out. Then an evaluation how good magnetic refrigeration applies to each of these technologies was performed. For this purpose a calculation tool to determine the coefficient of performance ( COP) and the exergy efficiency as a function of the magnetic field strength and the rotation frequency of a rotary-type magnetic refrigerator was developed. The evaluation clearly shows that some application domains are more ideal for a replacement of conventional refrigerators by their magnetic counterparts than others. In the pre-study, four good examples were chosen for a more comprehensive investigation and working out of more detailed results. In this article, the calculation method is briefly described. COP values and exergy efficiencies of one very suitable technology, namely the magnetic household refrigerator, are presented for different operation conditions. Summarizing, it is stated that magnetic refrigeration is a serious environmentally benign alternative to some conventional cooling, refrigeration and air-conditioning technologies.

Kitanovski, Andrej; Egolf, Peter W.

2009-04-01

183

Control system for thermoelectric refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

184

Helium dilution refrigeration system  

DOEpatents

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

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

1988-01-01

185

Thermoelectric refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

186

Intra-molecular refrigeration in enzymes  

E-print Network

We present a simple mechanism for intra-molecular refrigeration, where parts of a molecule are actively cooled below the environmental temperature. We discuss the potential role and applications of such a mechanism in biology, in particular in enzymatic reactions.

Hans J. Briegel; Sandu Popescu

2009-12-14

187

Special dilution refrigerator systems of Milli-Kelvin detector experiments  

SciTech Connect

Several hundred ultra low temperature systems have been designed and built for a variety of applications. One common application is the refrigeration of low temperature detectors. Although many of the requirements are satisfied by standard designs, Oxford Instruments has often built special refrigerators to suit specific detector requirements. A few of the most interesting of these systems will be discussed. (1) dilution refrigerators to cool gravitational wave antennae to 65 mK; (2) rotating dilution refrigerator for cosmic ray detector experiments; (3) compact dilution refrigerator to cool large bolometer arrays within the SCUBA telescope; (4) side access systems for beam line experiments

Batey, G.; Balshaw, N. (Oxford Instruments Ltd., Old Station Way (United Kingdom))

1993-11-01

188

Compact acoustic refrigerator  

SciTech Connect

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

189

Compact acoustic refrigerator  

DOEpatents

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

Bennett, G.A.

1992-11-24

190

Thermodynamic study of air-cycle and mercury-vapor-cycle systems for refrigerating cooling air for turbines or other components  

NASA Technical Reports Server (NTRS)

An analysis of air refrigeration systems indicated that air cycles are generally less satisfactory than simple heat exchangers unless high component efficiencies and high values of heat-exchanger effectiveness can be obtained. A system employing a mercury-vapor cycle appears to be feasible for refrigerating air that must enter the system at temperature levels of approximately 1500 degrees R, and this cycle is more efficient than the air cycle. Weight of the systems was not considered. The analysis of the systems is presented in a generalized dimensionless form.

Nachtigall, Alfred J; Freche, John C; Esgar, Jack B

1956-01-01

191

ARTI Refrigerant Database. [Quarterly progress report, 1 July 1993--30 September 1993  

SciTech Connect

The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R134a, R-141b, R-142b, R-143a, R-152a, R-227ea, R-245ca, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyol ester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.

Calm, J.M.

1993-11-28

192

Analysis of a combined Rankine–vapour–compression refrigeration cycle  

Microsoft Academic Search

This paper describes a theoretical analysis of a heat-powered refrigeration cycle, a combined Rankine–vapour–compression refrigeration cycle. This refrigeration cycle combines an Organic Rankine Cycle and a vapour–compression cycle. The cycle can be powered by low grade thermal energy as low as 60°C and can produce cooling temperature as low as ?10°C. In the analysis, two combined Rankine–vapour–compression refrigeration cycles were

Satha Aphornratana; Thanarath Sriveerakul

2010-01-01

193

A rocket-borne He-3 refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

194

Kylteknik ("KYL")Kylteknik ("KYL") RefrigerationRefrigerationRefrigerationRefrigeration  

E-print Network

, geothermal energy, solar energy, biogas fuel, etc. Absorption refrigeration involves absorption requires temperatures above 0 °C) Ammonia / water AR system /1Ammonia / water AR system /1 Hot Engineering Piispankatu 8, 20500 Turku 4/40 ...continues #12;Ammonia / water AR system /2Ammonia / water AR

Zevenhoven, Ron

195

Engineering analysis of the use of compression refrigerants in the thin polymer icemaker. Revision 2/96  

SciTech Connect

Preliminary designs for systems which satisfy code requirements using R-134a and R-C318 as refrigerants are developed. Standard thermodynamic and heat transfer analysis were used to determine expected performance for the systems. The R-C318 has a somewhat peculiar vapor/liquid equilibrium curve, and a novel heat exchanger was introduced to optimize performance of this refrigerant. These performance assessments with component and assembly cost estimates were combined to prepare life-cycle costs for the two new systems. Compared to commercially available systems, these ``polymer evaporator`` systems seem to be completely feasible technically and if successfully demonstrated, they should have substantial economic advantages over existing ice-making devices.

Leigh, R.W.; Andrews, J.W.

1996-02-01

196

Impact of cooking, cooling, and subsequent refrigeration on the growth or survival of Clostridium perfringens in cooked meat and poultry products.  

PubMed

In January 1999, the Food Safety and Inspection Service (FSIS) finalized performance standards for the cooking and chilling of meat and poultry products in federally inspected establishments. More restrictive chilling (stabilization) requirements were adopted despite the lack of strong evidence of a public health risk posed by industry practices employing the original May 1988 guidelines (U.S. Department of Agriculture FSIS Directive 7110.3). Baseline data led the FSIS to estimate a "worst case" of 10(4) Clostridium perfringens cells per g in raw meat products. The rationale for the FSIS performance standards was based on this estimate and the assumption that the numbers detected in the baseline study were spores that could survive cooking. The assumptions underlying the regulation stimulated work in our laboratory to help address why there have been so few documented outbreaks of C. perfringens illness associated with the consumption of commercially processed cooked meat and poultry products. Our research took into account the numbers of C. perfringens spores in both raw and cooked products. One hundred ninety-seven raw comminuted meat samples were cooked to 73.9 degrees C and analyzed for C. perfringens levels. All but two samples had undetectable levels (<3 spores per g). Two ground pork samples contained 3.3 and 66 spores per g. Research was also conducted to determine the effect of chilling on the outgrowth of C. perfringens spores in cured and uncured turkey. Raw meat blends inoculated with C. perfringens spores, cooked to 73.9 degrees C, and chilled according to current guidelines or under abuse conditions yielded increases of 2.25 and 2.44 log10 CFU/g for uncured turkey chilled for 6 h and an increase of 3.07 log10 CFU/g for cured turkey chilled for 24 h. No growth occurred in cured turkey during a 6-h cooling period. Furthermore, the fate of C. perfringens in cooked cured and uncured turkey held at refrigeration temperatures was investigated. C. perfringens levels decreased by 2.52, 2.54, and 2.75 log10 CFU/g in cured turkey held at 0.6, 4.4, and 10 degrees C, respectively, for 7 days. Finally, 48 production lots of ready-to-eat meat products that had deviated from FSIS guidelines were analyzed for C. perfringens levels. To date, 456 samples have been tested, and all but 25 (ranging from 100 to 710 CFU/g) of the samples contained C. perfringens at levels of <100 CFU/g. These results further support historical food safety data that suggest a very low public health risk associated with C. perfringens in commercially processed ready-to-eat meat and poultry products. PMID:12870757

Kalinowski, Robin M; Tompkin, R Bruce; Bodnaruk, Peter W; Pruett, W Payton

2003-07-01

197

Enclosure for thermoelectric refrigerator and method  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

198

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

NASA Astrophysics Data System (ADS)

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

Sendil Kumar, D.; Elansezhian, R.

2014-03-01

199

Correlation and prediction of dense fluid transport coefficients. VII. Refrigerants  

NASA Astrophysics Data System (ADS)

A recently developed scheme, based on considerations of hard-sphere theory, is used for the simultaneous correlation of the coefficients of viscosity and thermal conductivity for the refrigerants R11, R12, R22, R32. R124, R125, R134a, R141b, and R152a in excellent agreement with experiment, over extended temperature and pressure ranges. Values for the roughness factors and correlations for the characteristic volume are presented. The overall average absolute deviations of the experimental viscosity and thermal conductivity measurements from those calculated by the correlation are 2.1 and 2.3%, respectively, over a temperature range from 200 to about 10 K below the critical temperature and a pressure range from saturation to about 40 MPa. Since the proposed scheme is based on recent and accurate density values, a Tail-type equation was also employed to correlate successfully the density of the refrigerants. The overall average absolute deviation of the experimental density measurements from those calculated by the correlation is ±0.08%.

Assael, M. J.; Dymond, J. H.; Polimatidou, S. K.

1995-05-01

200

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

201

Thermoacoustic Refrigerator's Stack Optimization  

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

202

Comparative efficiencies and implications for greenhouse gas emissions of chiller refrigerants  

Microsoft Academic Search

This paper summarizes analyses of refrigerant options for chillers. Chillers are ma- chines that cool water or other liquids for use in large air-conditioning and refrigeration systems. Their operation for comfort and process cooling consumes substantial energy with resulting green- house gas (GHG) emissions. Moreover, leaked and otherwise released refrigerants act as GHGs, also contributing to global climate change. This

James M. Calm

2005-01-01

203

Pot-in-Pot Refrigeration  

NSDL National Science Digital Library

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

Omsi

2004-01-01

204

Closed cycle liquid helium refrigerators  

NASA Astrophysics Data System (ADS)

We have developed closed cycle liquid helium refrigerators using a Joule Thomson circuit precooled by commercially available two staged Gifford Mac Mahon cryocoolers. The Joule Thomson counterflow heat exchangers are modular and have been thermo-hydraulically characterized. Fully automatic cool down and operation are achieved by two pneumatically driven by pass and expansion valves. Several apparatus have been built or are under assembly with cooling power ranging from 100 mW up to 5 Watt, for temperature ranging from 2.8 K up to 4.5 K. A trouble free operation with several warm up and cool down cycles has been proven over 7000 hours.

Claudet, G.; Lagnier, R.; Ravex, A.

205

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

206

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

207

Ground Loops for Heat Pumps and Refrigeration  

E-print Network

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

Braud, H. J.

1986-01-01

208

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

209

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

210

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

211

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

212

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

213

ARTI refrigerant database  

SciTech Connect

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

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

1999-01-01

214

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

215

Malone cycle refrigerator development  

SciTech Connect

This paper describes the progress made in demonstrating a Malone Cycle Refrigerator/Freezer. The Malone cycle is similar to the Stirling cycle but uses a supercritical fluid in place of real gas. In the approach, solid-metal diaphragms are used to seal and sweep the working volumes against the high working fluid pressures required in Malone cycle machines. This feature eliminates the friction and leakage that accounted for nearly half the losses in the best piston-defined Malone cycle machines built to date. The authors successfully built a Malone cycle refrigerator that: (1) used CO{sub 2} as the working fluid, (2) operated at pressures up to 19.3 Mpa (2,800 psi), (3) achieved a cold end metal temperatures of {minus}29 C ({minus}20 F), and (4) produced over 400 Watts of cooling at near ambient temperatures. The critical diaphragm components operated flawlessly throughout characterization and performance testing, supporting the conclusion of high reliability based on analysis of fatigue date and actual strain measurements.

Shimko, M.A.; Crowley, C.J.

1999-07-01

216

Chemical and thermal stability of refrigerant-lubricant mixture with metal  

SciTech Connect

This report presents completed sealed tube stability test results for the R-123/mineral oil mixture and preliminary results for seven of the eighteen contracted refrigerant-lubricant mixtures. The R-123 mixture was tested at 105, 150, and 175{degrees}C. The results obtained indicate that prolonged exposure to temperatures of about 150{degree}C and higher will lead to rapid chemical deterioration of the R-123/mineral oil system. Chlorotrifluoroethane (R-133a) and trifluoroethane (R-143a) have been identified as decomposition products of R-123. Testing at 150 and 175{degrees}C have been completed for the HCFC refrigerants R-22, R-124, and R-142b with either mineral oil or alkylbenzene lubricants. These mixtures were very stable at the indicated temperatures. Testing at a higher temperature level will be necessary to define their upper temperature limits. Similarily, partial test results are available for HFC refrigerants R-32, R-125, R-134a (two esters), and R-143a with pentaerythritol ester lubricants at the 150 and 175{degrees}C temperature levels. Again, all five mixtures were found to be extremely stable at the test temperatures and additional testing will be needed to establish their upper temperature limits.

Huttenlocher, D.F. (Spauschus Associates, Inc., Atlanta, GA (United States))

1992-03-31

217

Kylteknik ("KYL")Kylteknik ("KYL") RefrigerationRefrigerationRefrigerationRefrigeration  

E-print Network

/pressure combination, unlike freezing / melting, and i l t h t ff t (H >> H ) finvolves greater heat effects (Hvaporisation >> Hmelting), for example: water The Carnot power cycle can be executed in a reverse within the 8-cooling a bit beyond (3) reduces the risk of "flashing" i h For each step: (Qin - Qout) + (Win -Wout) + 8

Zevenhoven, Ron

218

Visualization and measurement of refrigerant flow in compression-type refrigerator by neutron radiography  

NASA Astrophysics Data System (ADS)

The refrigerant two-phase flows in a capillary tube and a distributor used in a compression-type refrigerator were visualized by real-time neutron radiography. The thermal neutron radiography system of JRR-3M at the Japan Atomic Energy Research Institute was used. In the visualization experiments of the two-phase flow in the capillary tube of 2 mm I.D., a cooled CCD camera was used, and the axial one-dimensional distributions of void fraction were measured. For the distributor, a high sensitivity video camera with a silicone intensified target tube was used. From the visualized images, the refrigerant behaviors in the distributor were clearly shown, and the liquid fraction in each tube was measured. As a result, it was shown that the refrigerant behaviors in the distributor effected the distributing performance of the refrigerant flow.

Asano, H.; Takenaka, N.; Fujii, T.; Shibata, Y.; Ebisu, T.; Matsubayashi, M.

1999-11-01

219

Availability of refrigerants for heat pumps in Europe  

E-print Network

sources Space Heating + Cooling Tumble dryer Domestic Hot Water Refrigerator Freezer R-410AR-134a R-410A R IIZW e.V. #12;11 Requirements Physical properties Thermo dynamical properties Chemical properties Physiological properties Economic requirements Ecological properties The use of a substance as a refrigerant

Oak Ridge National Laboratory

220

Refrigerating machine oil  

SciTech Connect

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

Nozawa, K.

1981-03-17

221

Visualization and measurement of refrigerant flow in compression-type refrigerator by neutron radiography  

Microsoft Academic Search

The refrigerant two-phase flows in a capillary tube and a distributor used in a compression-type refrigerator were visualized by real-time neutron radiography. The thermal neutron radiography system of JRR-3M at the Japan Atomic Energy Research Institute was used. In the visualization experiments of the two-phase flow in the capillary tube of 2mm I.D., a cooled CCD camera was used, and

H. Asano; N. Takenaka; T. Fujii; Y. Shibata; T. Ebisu; M. Matsubayashi

1999-01-01

222

Proceedings of the 1993 non-fluorocarbon insulation, refrigeration and air conditioning technology workshop  

SciTech Connect

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.

Not Available

1994-09-01

223

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.

224

Stirling-type pulse tube refrigerator with slit-type heat exchangers for HTS superconducting motor  

NASA Astrophysics Data System (ADS)

A cryogenic refrigeration system is one of the indispensable components for cooling superconducting motor or generator. Among various configurations of cryogenic refrigeration system, the on-board refrigeration system is considered to be attractive for compactness and small heat leak. In order to turn this concept into reality, we focus on two essential points; development of the specific structure for on-board refrigeration and optimal design of the refrigerator. Since the on-board refrigeration system should not create unbalanced vibration, the inline Stirling-type pulse tube refrigerator is considered as a good candidate and more concrete and efficient structure is developed under the design constraints. The dynamic absorber is used to maintain the dynamic stability of the single acting linear compressor. To increase thermal Carnot efficiency with the on-board Stirling-type pulse tube refrigerator, slit-type heat exchangers are implemented and flow straighteners are carefully designed by the three-dimensional CFD simulation. The overall configuration of the Stirling-type pulse tube refrigerator is designed and fabricated by the optimal process. The present on-board refrigerator has the cooling capacity of 7 W at 59.5 K with the Carnot efficiency of 10.9%. According to these experimental results, the pulse tube refrigerator as the on-board refrigeration system possesses a sufficient thermal efficiency despite the restricted design configuration. The on-board refrigeration is considered as a useful method for cooling HTS superconducting motor.

Ki, Taekyung; Jeong, Sangkwon

2011-06-01

225

Shuttle kit freezer refrigeration unit conceptual design  

NASA Technical Reports Server (NTRS)

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

Copeland, R. J.

1975-01-01

226

Optimal Sequencing of Central Refrigeration Equipment in an Industrial Plant  

E-print Network

A model was developed to find a viable solution to the problem of selecting the optimal sequence of refrigeration equipment (chillers, cooling towers, pumps) to operate in a Central Utility Plant. The optimal equipment sequence is that sequence...

Fiorino, D. P.; Priest, J. W.

1986-01-01

227

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

228

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

229

Plant Site Refrigeration Upgrade  

E-print Network

Bayer Corporation operates a multi-division manufacturing facility in Bushy Park, South Carolina. Low temperature refrigeration (-4°F) is required by many of the chemical manufacturing areas and is provided by a Plant Site Refrigeration System...

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

230

Quantum-enhanced absorption refrigerators  

E-print Network

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

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

2014-02-05

231

Quantum-enhanced absorption refrigerators.  

PubMed

Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators. PMID:24492860

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

2014-01-01

232

Quantum-enhanced absorption refrigerators  

PubMed Central

Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators. PMID:24492860

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

2014-01-01

233

Auto defrost refrigerator  

SciTech Connect

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

Schulze, J.L.

1988-05-03

234

Save with Hybrid Refrigeration  

E-print Network

of refrigeration, consisting of an ammonia absorption refrigeration (AAR) unit and a mechanical compression refrigera tion (MCR) unit, is presented in this article. This paper will briefly describe process configur ation, advantages and utility consumption..., equip ment cost and direct field cost comparisons of such a hybri~ refrigeration unit over its coun terpart, a cascading MCR unit, in a Rectisol application. INTRODUCTION COMBINING REFRIGERATION SYSTEMS can save energy where two levels...

Chung, C. W.

235

Optimal performance of endoreversible quantum refrigerators  

E-print Network

The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results which are model-independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for \\textit{any} endoreversible quantum refrigerator. At striking variance with the \\textit{universality} of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics.

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

2014-08-03

236

Optimal performance of endoreversible quantum refrigerators  

NASA Astrophysics Data System (ADS)

The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results that are model independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for any endoreversible quantum refrigerator. At striking variance with the universality of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics.

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

2014-12-01

237

An electrocaloric refrigerator without external regenerator  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

238

Alternative refrigerant performance: Field test of a nonchlorofluorocarbon chiller at Fort Leonard Wood, MO. Final report  

Microsoft Academic Search

Production of chlorofluorocarbon (CFC) refrigerants will stop permanently by the end of 1995, and air-conditioning and refrigeration (AC\\/R) systems will have to use alternatives to CFC. The U.S. Army`s AC\\/R systems have a total cooling capacity of more than 1 million tons; approximately 55 percent of these systems use CFC-based refrigerants. Chillers currently using CFC refrigerants must be replaced or

C. W. Sohn; J. J. Tomlinson; N. C. Herring; B. E. Boughton

1995-01-01

239

Alternative refrigerant performance: Field test of a nonchlorofluorocarbon chiller at Fort Leonard Wood, MO  

Microsoft Academic Search

Production of chlorofluorocarbon (CFC) refrigerants will stop permanently by the end of 1995, and air-conditioning and refrigeration (AC\\/R) systems will have to use alternatives to CFC. The U.S. Army's AC\\/R systems have a total cooling capacity of more than 1 million tons; approximately 55 percent of these systems use CFC-based refrigerants. Chillers currently using CFC refrigerants must be replaced or

Chang W. Sohn; John J. Tomlinson; Nancy C. Herring; Brian E. Boughton

1995-01-01

240

Energy-efficiency directory of refrigerators and refrigerator-freezers  

Microsoft Academic Search

Information is presented about the energy costs of operating refrigerators and refrigerator-freezers and includes the type of refrigerator or refrigerator-freezer, the fresh food volume, the freezer volume, the total volume, and the yearly energy cost. The directory lists all currently marketed electric refrigerators and refrigerator-freezers that have Energy Guide labels. The Federal Trade Commission requires manufacturers who distribute refrigerators and

T. G. Statt; J. L. Coggins

1981-01-01

241

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

242

A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus  

SciTech Connect

This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

Raustad, Richard A. [Florida Solar Energy Center

2013-01-01

243

Dilution Refrigerator for Nuclear Refrigeration and Cryogenic Thermometry Studies  

NASA Astrophysics Data System (ADS)

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

Nakagawa, Hisashi; Hata, Tohru

2014-07-01

244

A State-of-the-Art Review of Compact Vapor Compression Refrigeration Systems and Their Applications  

Microsoft Academic Search

We present a critical review of the literature on the fundamentals, design, and application aspects of compact and miniature mechanical vapor compression refrigeration systems. Examples of such systems are those envisaged for electronics and personal cooling. In comparison to other refrigeration technologies (e.g., solid-state), vapor compression enables the attainment of low evaporating temperatures while maintaining a large cooling capacity per

Jader R. Barbosa Jr; Guilherme B. Ribeiro; Pablo A. de Oliveira

2012-01-01

245

A STATE-OF-THE-ART REVIEW OF COMPACT VAPOR COMPRESSION REFRIGERATION SYSTEMS AND THEIR APPLICATIONS  

Microsoft Academic Search

We present a critical review of the literature on the fundamentals, design and application aspects of compact and miniature mechanical vapor compression refrigeration systems. Examples of such systems are those envisaged for electronics and personal cooling. In comparison to other refrigeration technologies (e.g., solid-state), vapor compression enables the attainment of low evaporating temperatures whilst maintaining a large cooling capacity per

Jader R. Barbosa Jr; Guilherme B. Ribeiro; Pablo A. de Oliveira

2011-01-01

246

Chemical and thermal stability of refrigerant-lubricant mixture with metal. Materials compatibility and lubricants research on CFC-refrigerant substitutes: Quarterly report, 1 February 1992--31 March 1992  

SciTech Connect

This report presents completed sealed tube stability test results for the R-123/mineral oil mixture and preliminary results for seven of the eighteen contracted refrigerant-lubricant mixtures. The R-123 mixture was tested at 105, 150, and 175{degrees}C. The results obtained indicate that prolonged exposure to temperatures of about 150{degree}C and higher will lead to rapid chemical deterioration of the R-123/mineral oil system. Chlorotrifluoroethane (R-133a) and trifluoroethane (R-143a) have been identified as decomposition products of R-123. Testing at 150 and 175{degrees}C have been completed for the HCFC refrigerants R-22, R-124, and R-142b with either mineral oil or alkylbenzene lubricants. These mixtures were very stable at the indicated temperatures. Testing at a higher temperature level will be necessary to define their upper temperature limits. Similarily, partial test results are available for HFC refrigerants R-32, R-125, R-134a (two esters), and R-143a with pentaerythritol ester lubricants at the 150 and 175{degrees}C temperature levels. Again, all five mixtures were found to be extremely stable at the test temperatures and additional testing will be needed to establish their upper temperature limits.

Huttenlocher, D.F. [Spauschus Associates, Inc., Atlanta, GA (United States)

1992-03-31

247

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

248

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

249

Magnetic refrigerator for hydrogen liquefaction  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

250

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. 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 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. Citations in this report are divided into the following topics: thermophysical properties; materials compatibility; lubricants and tribology; application data; safety; test and analysis methods; impacts; regulatory actions; substitute refrigerants; identification; absorption and adsorption; research programs; and miscellaneous documents. Information is also presented on ordering instructions for the computerized version.

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

1996-04-15

251

Refrigeration systems program summary  

NASA Astrophysics Data System (ADS)

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 pct. of the CFCs consumed by the U.S. are due to refrigeration systems. As the international Montreal Protocol will phase out CFC compounds no later than 2000, there is tremendous need to develop safe non-CFC refrigerants and working fluids, alternative refrigeration cycles, and non-CFC insulations for appliances. The U.S. Department of Energy (DOE) established the Refrigeration System Program in 1977 to lead a national effort to accelerate the deployment of cost effective and energy efficient air conditioning and refrigeration technologies. The program primarily conducts research and development on advanced refrigeration technologies. The program, managed by the Office of Building Technologies, which reports to DOE's Assistant Secretary for Conversation and Renewable Energy, encompasses several key activities such as investigating alternative refrigerants and refrigeration cycles, developing advanced technologies for future air conditioning and refrigeration equipment designs, and developing advanced appliance insulations.

1991-12-01

252

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

NASA Astrophysics Data System (ADS)

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

Fischer, S. K.

253

The application of Stirling cooler to refrigeration  

SciTech Connect

The application field of the free-piston Stirling Cooler, Model 100A of Global Cooling BV in the refrigeration has been studied. The cooling effectiveness of the free-piston Stirling Cooler which means small capacity with better efficiency, large range of temperature and capacity modulated operation is of much use to cool a space insulated well. One practicable application is suggested here, in which FPSC and secondary heat transfer fluid are used to the single temperature refrigerator (60 liter) instead of conventional vapor compression machines. In the freezer operation at {minus}20 C inside cabinet, the steady-state test results show 25% improvement in energy consumption over original one. The application of free-piston Stirling Cooler to a freezer at lower temperature shows great potentials also.

Kim, S.Y.; Chung, W.S.; Shin, D.K.; Cho, K.S. [LG Electronics Inc., Seoul (Korea, Republic of). Living System Lab.

1997-12-31

254

Experimental investigation of an alternating evaporator duty refrigerator/freezer  

SciTech Connect

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

Lavanis, M.; Haider, I.; Radermacher, R. [Univ. of Maryland, College Park, MD (United States)

1998-12-31

255

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

256

ARTI refrigerant database  

SciTech Connect

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

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

1998-08-01

257

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

258

Energy-efficiency directory of refrigerators and refrigerator-freezers  

SciTech Connect

Information is presented about the energy costs of operating refrigerators and refrigerator-freezers and includes the type of refrigerator or refrigerator-freezer, the fresh food volume, the freezer volume, the total volume, and the yearly energy cost. The directory lists all currently marketed electric refrigerators and refrigerator-freezers that have Energy Guide labels. The Federal Trade Commission requires manufacturers who distribute refrigerators and refrigerator-freezers to attach Energy Guide labels to appliances manufactured on or after May 19, 1980. The data have been measured by manufacturers and/or their agents according to US Government standard test procedures.

Statt, T.G.; Coggins, J.L.

1981-06-01

259

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

260

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

261

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

262

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

263

Waste Heat Recovery from Refrigeration  

E-print Network

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

Jackson, H. Z.

1982-01-01

264

A sub-Kelvin superfluid pulse tube refrigerator driven by paramagnetic fountain effect pump  

NASA Astrophysics Data System (ADS)

A novel sub-Kelvin refrigeration cycle is introduced in this work. The magnetically driven superfluid pulse tube refrigerator (MSPTR) could provide cooling at temperatures below 200 mK while rejecting heat at 1.6 K and contains no moving mechanical parts. The MSPTR cycle has an advantage over other types of sub-Kelvin cooling in that it can provide distributed cooling. Additionally the MSPTR unlike the dilution refrigerator will be able to function in microgravity without any modification. This work includes a description of the MSPTR cycle and a summary of preliminary design calculations including results used to size components and predict cooling performance.

Jahromi, Amir E.; Miller, Franklin K.

2014-07-01

265

Load leveling on industrial refrigeration systems  

NASA Astrophysics Data System (ADS)

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

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

1982-01-01

266

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

267

Analysis of a domestic refrigerator cycle with an ejector  

SciTech Connect

In this paper, an improved cooling cycle for a conventional domestic refrigerator-freezer utilizing an ejector for vapor precompression is analyzed using an idealized model Its energy efficiency is compared to that of the conventional refrigerator-freezer system. Emphasis is placed on off-design conditions. The ejector-enhanced refrigeration cycle consists of two evaporators that operate at different pressure and temperature levels. The ejector combines the vapor flows exiting the two evaporators into one at an intermediate pressure level The ejector cycle gives an increase of up to 12.4% in the coefficient of performance (COP) compared to that of a standard refrigerator-freezer refrigeration cycle. The analysis includes calculations on the optimum throat diameters of the ejector. The investigation on the off-design performance of the ejector cycle shows little dependency of energy consumption on constant ejector throat diameters.

Tomasek, M.L.; Radermacher, R. [Univ. of Maryland, College Park, MD (United States)

1995-08-01

268

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 3.0MPa mean pressure, 57.7Hz frequency, and 2.2kW heat input, the experimental cooler provides a lowest temperature of -64.4°C and 250W 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

269

Influence of Oil on Refrigerant Evaporator Performance  

NASA Astrophysics Data System (ADS)

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

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

270

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

271

Measurements of optical refrigeration in ytterbium-doped crystals  

NASA Astrophysics Data System (ADS)

We measured anti-Stokes fluorescence cooling (optical refrigeration) in ytterbium-doped yttrium aluminum garnet (YAG). Pumping the 2.3% Yb3+:YAG crystal with 1.8 W of 1030 nm laser light produced a temperature drop of 8.9 °C from room temperature. The high thermal conductivity and ruggedness of this crystal make it an attractive material for use in optical refrigerators. Our spectral studies show that pure crystals of this material could be efficient for optical refrigeration at temperatures above ˜100 K. Photothermal deflection measurements show that our current crystals can cool at ˜250 K. Additionally, we measured optical refrigeration in a 5% Yb3+:Y2SiO5 crystal when pumped at 1050 nm.

Epstein, R. I.; Brown, J. J.; Edwards, B. C.; Gibbs, A.

2001-11-01

272

Development of a hybrid refrigerator combining thermoelectric and vapor compression technologies  

Microsoft Academic Search

A domestic refrigerator with three compartments has been developed: refrigerator compartment, at 4°C (vapor compression cooling system); freezer compartment, at ?22°C (vapor compression cooling system); and a new super-conservation compartment, at 0°C (thermoelectric cooling system). The thermoelectric system designed for the super-conservation compartment eliminates the oscillation of its temperature due to the start and stop compressor cycles, obtaining a constant

J. G. Vián; D. Astrain

2009-01-01

273

Custom-built research refrigerators for ultra-low temperature  

Microsoft Academic Search

The Janis line of ultra-low-temperature research refrigerators is presented. Cryogen-containing and cryogen-free 3He, 3He–4He dilution and adiabatic demagnetization refrigerators for the mK temperature range are described in detail and their possible use for cooling low-temperature sensors and detectors is discussed. A special emphasis is made on the Janis temperature scale down to 10mK, maintained with a newly designed compact CMN

Vladimir Shvarts; Lewis Bobb; Munir Jirmanus; Zuyu Zhao

2004-01-01

274

Two-watt, 4-Kelvin closed cycle refrigerator performance  

NASA Technical Reports Server (NTRS)

A 2-watt, 4-K helium refrigerator using the Gifford-McMahon/Joule Thomson cycle is described. The unit features a removable displacer cylinder and high-efficiency, low-pressure drop heat exchangers. These improvements result in a 100 percent increase in cooling power over the existing Deep Space Network system. The effects of the heat exchanger efficiency and Gifford-McMahon expander performance on refrigerator capacity are also discussed.

Britcliffe, M.

1987-01-01

275

Quantum refrigerators in quest of the absolute zero  

NASA Astrophysics Data System (ADS)

The second and third laws of thermodynamics can be used to establish a fundamental bound for the maximum possible cooling rate in approaching the absolute zero of temperature. In modeling the behavior of the molecular refrigerators geared toward attaining ultralow temperatures, only quantum mechanical, as opposed to classical physics, models can be admissible. As a simple model, we analyze a three-level quantum refrigerator, and in particular its irreversible thermodynamic performance as absolute zero is approached.

Kosloff, Ronnie; Geva, Eitan; Gordon, Jeffrey M.

2000-06-01

276

Thermal design and tests of a subcooled superfluid helium refrigerator  

NASA Astrophysics Data System (ADS)

Design methods for a subcooled superfluid helium refrigerator with high efficiency are studied. The design details are presented for a He I heat exchanger (perforated disk stack type), a He II heat exchanger (low fin tube type), an expansion valve, a safety valve, an initial filling valve and a pumping system. Heat loss, cooling capacity and cooldown time are also calculated. The test results for the trial-manufactured refrigeration system are presented in comparison with the designed values.

Hakuraku, Y.; Ogata, H.

277

AMR (Active Magnetic Regenerative) refrigeration for low temperature  

NASA Astrophysics Data System (ADS)

This paper reviews AMR (Active Magnetic Regenerative) refrigeration technology for low temperature applications that is a novel cooling method to expand the temperature span of magnetic refrigerator. The key component of the AMR system is a porous magnetic regenerator which allows a heat transfer medium (typically helium gas) to flow through it and therefore obviate intermittently operating an external heat switch. The AMR system alternatingly heats and cools the heat transfer medium by convection when the magneto-caloric effect is created under varying magnetic field. AMR may extend the temperature span for wider range than ADR (Adiabatic Demagnetization Refrigerator) at higher temperatures above 10 K because magneto-caloric effects are typically concentrated in a small temperature range in usual magnetic refrigerants. The regenerative concept theoretically enables each magnetic refrigerant to experience a pseudo-Carnot magnetic refrigeration cycle in a wide temperature span if it is properly designed, although adequate thermodynamic matching of strongly temperature-dependent MCE (magneto-caloric effect) of the regenerator material and the heat capacity of fluid flow is often tricky due to inherent characteristics of magnetic materials. This paper covers historical developments, fundamental concepts, key components, applications, and recent research trends of AMR refrigerators for liquid helium or liquid hydrogen temperatures.

Jeong, Sangkwon

2014-07-01

278

Socioeconomic impacts associated with proposed energy efficiency standards for refrigerators, refrigerator-freezers, freezers, room air conditioners, and central air conditioners  

Microsoft Academic Search

Socio-economic and environmental impacts that may be associated with the proposed efficiency standards for refrigerators, refrigerator\\/freezers and freezers, room air conditioners (RACs), central air conditioners (CACs) and heat pumps in the cooling mode are assessed. The proposed standards in use at the initiation of this study were those dated May 14, 1976. The proposed standards were revised prior to the

W. Dwyer; J. Toor; R. Rettberg; W. Gilliam; J. Cole

1976-01-01

279

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

280

Solar adsorption refrigeration (SAR) system modeling  

Microsoft Academic Search

The solar adsorption refrigeration (SAR) system has economical and environmental aspects that motivate many researches to\\u000a investigate its capability in cooling system design. In this study, multi-dimensional mathematical models have been generated\\u000a to predict the coefficient of performance (COP) value of the SAR system as function of the evaporator, condenser, and generator\\u000a temperatures. Fuzzy logic and regression analysis approaches were

Ghassan M. Tashtoush; Mohannad Al-Ata; Atif Al-Khazali

2011-01-01

281

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

282

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

283

A general computer model for predicting the performance of gas sorption refrigerators  

NASA Technical Reports Server (NTRS)

Projected performance requirements for cryogenic spacecraft sensor cooling systems which demand higher reliability and longer lifetimes are outlined. The gas/solid sorption refrigerator is viewed as a potential solution to cryogenic cooling needs. A software model of an entire gas sorption refrigerator system was developed. The numerical model, evaluates almost any combination and order of refrigerator components and any sorbent-sorbate pair or which the sorption isotherm data are available. Parametric curves for predicting system performance were generated for two types of refrigerators, a LaNi5-H2 absorption cooler and a Charcoal-N2 adsorption cooler. It is found that precooling temperature and heat exchanger effectiveness affect the refrigerator performance. It is indicated that gas sorption refrigerators are feasible for a number of space applications.

Sigurdson, K. B.

1983-01-01

284

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

285

Counter-Top Thermoacoustic Refrigerator- An Experimental Investigation  

NASA Astrophysics Data System (ADS)

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°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

2010-06-01

286

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

2012-06-01

287

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

288

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

SciTech Connect

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%. 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. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

1995-09-01

289

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

290

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

291

Joule Thomson refrigerator  

NASA Astrophysics Data System (ADS)

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

Chan, Chung K.; Gatewood, John R.

1988-10-01

292

Optimum design on refrigeration system of high-repetition-frequency laser  

NASA Astrophysics Data System (ADS)

A refrigeration system with fluid cycle, semiconductor cooler and air cooler is designed to solve the problems of thermal lensing effect and unstable output of high-repetition-frequency solid-state lasers. Utilizing a circulating water pump, water recycling system carries the water into laser cavity to absorb the heat then get to water cooling head. The water cooling head compacts cold spot of semiconductor cooling chips, so the heat is carried to hot spot which contacts the radiating fins, then is expelled through cooling fan. Finally, the cooled water return to tank. The above processes circulate to achieve the purposes of highly effective refrigeration in miniative solid-state lasers.The refrigeration and temperature control components are designed strictly to ensure refrigeration effect and practicability. we also set up a experiment to test the performances of this refrigeration system, the results show that the relationship between water temperature and cooling power of semiconductor cooling chip is linear at 20°C-30°C (operating temperature range of Nd:YAG), the higher of the water temperature, the higher of cooling power. According to the results, cooling power of single semiconductor cooling chip is above 60W, and the total cooling power of three semiconductor cooling chips achieves 200W that will satisfy the refrigeration require of the miniative solid-state lasers.The performance parameters of laser pulse are also tested, include pulse waveform, spectrogram and laser spot. All of that indicate that this refrigeration system can ensure the output of high-repetition-frequency pulse whit high power and stability.

Li, Gang; Li, Li; Jin, Yezhou; Sun, Xinhua; Mao, Shaojuan; Wang, Yuanbo

2014-12-01

293

Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander  

E-print Network

Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander Jun Lan Yang is performed for the transcritical carbon dioxide refrigeration cycles with a throttling valve compression cycle is applicable for carbon dioxide for water heating and comfort cooling and heating [4

Bahrami, Majid

294

Modeling and Simulation for Intelligent Control of Expansion Valve in Vapour Compression Refrigeration System  

Microsoft Academic Search

Conventional control techniques are not able to accomplish the stable cooling in VCRS (vapour compression refrigeration system) of air conditioning system. This article describes the fuzzy modeling and simulation for intelligent control to regulate the opening area of expansion valve for better and stable refrigerant flow even in the presence of operating condition change. Fuzzy logic control of expansion valve

Jagdev Singh; Nirmal Singh; J. K. Sharma

2007-01-01

295

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

296

Improving Control in a Joule-Thomson Refrigerator  

NASA Technical Reports Server (NTRS)

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

Borders, James; Pearson, David; Prina, Mauro

2005-01-01

297

Determination of a vapor compression refrigeration system refrigerant charge  

NASA Astrophysics Data System (ADS)

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

Yang, Chun-Xin; Dang, Chao-Bin

1995-09-01

298

Polymer-based electrocaloric cooling devices  

DOEpatents

Cooling devices (i.e., refrigerators or heat pumps) based on polymers which exhibit a temperature change upon application or removal of an electrical field or voltage, (e.g., fluoropolymers or crosslinked fluoropolymers that exhibit electrocaloric effect).

Zhang, Qiming; Lu, Sheng-Guo; Li, Xinyu; Gorny, Lee; Cheng, Jiping; Neese, Bret P; Chu, Baojin

2014-10-28

299

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2014 CFR

...Fuel Burning Systems § 3280.714...of providing follow-up service. ...unitary cooling systems with rated...being served. A control shall be provided...of providing follow-up service. ...refrigerating systems serving...

2014-04-01

300

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2012 CFR

...Fuel Burning Systems § 3280.714...of providing follow-up service. ...unitary cooling systems with rated...being served. A control shall be provided...of providing follow-up service. ...refrigerating systems serving...

2012-04-01

301

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2013 CFR

...Fuel Burning Systems § 3280.714...of providing follow-up service. ...unitary cooling systems with rated...being served. A control shall be provided...of providing follow-up service. ...refrigerating systems serving...

2013-04-01

302

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2011 CFR

...Fuel Burning Systems § 3280.714...of providing follow-up service. ...unitary cooling systems with rated...being served. A control shall be provided...of providing follow-up service. ...refrigerating systems serving...

2011-04-01

303

Quantum optics: Cool computation, hot bits  

NASA Astrophysics Data System (ADS)

Quantum information processing provides novel methods for pumping heat and refrigerating photons. Devices that obtain and manipulate information at the quantum level can function as quantum 'Maxwell's demons' to cool systems in ways that liquid helium cannot.

Lloyd, Seth

2014-02-01

304

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

305

Dry dilution refrigerator with 4He-1 K-loop  

NASA Astrophysics Data System (ADS)

In this article we summarize experimental work on cryogen-free 3He/4He dilution refrigerators which, in addition to the dilution refrigeration circuit, are equipped with a 4He-1 K-stage. This type of DR becomes worth considering when high cooling capacities are needed at T ? 1 K to cool cold amplifiers and heat sink cables. In our application, the motivation for the construction of this type of cryostat was to do experiments on superconducting quantum circuits for quantum information technology and quantum simulations. In other work, DRs with 1 K-stage were proposed for astro-physical cryostats. For neutron scattering research, a top-loading cryogen-free DR with 1 K-stage was built which was equipped with a standard commercial dilution refrigeration insert. Cooling powers of up to 100 mW have been reached with our 1 K-stage, but higher refrigeration powers were achieved with more powerful pulse tube cryocoolers and higher 4He circulation rates in the 1 K-loop. Several different versions of a 1 K-loop have been tested in combination with a dilution refrigeration circuit. The lowest temperature of our DR was 4.3 mK.

Uhlig, Kurt

2015-03-01

306

A central refrigeration system to support multiple environmental test chambers: Design, development, and evaluation  

NASA Astrophysics Data System (ADS)

A pilot plant project was undertaken to develop a central refrigeration compressor station capable of providing the necessary cooling to a network of nine independently-controlled environmental test chambers operating at temperatures of minus 85 F to 350 F. Design features of the central two-stage (cascade) vapor compression refrigeration system are described. Computer control of the central refrigeration station is a major contribution to the improved efficiency of the overall system. A second computer-control system was developed to perform the task of environmental chamber control, test management, and chamber performance monitoring. Data on performance of the Climatic Central Refrigeration System (CCRS) are presented.

Baca, R. G.; Miller, K. M.; Shipley, K. L.

1990-11-01

307

Refrigerator recycling and CFCs  

SciTech Connect

Utility-sponsored refrigerator and freezer pick-up programs have removed almost 900,000 inefficient appliances from the North American electric grid to date. While the CFC-12 refrigerant from the discarded appliances is typically removed and recycled, in all but a few programs the CFC-11 in the foam insulation is not. About a quarter-billion pounds of CFC-11 are banked in refrigerator foam in the United States. Release of this ``bank`` of CFC, combined with that from foam insulation used in buildings, will be the largest source of future emissions if preventive measures are not taken. Methods exist to recover the CFC for reuse or to destroy it by incineration. The task of recycling or destroying the CFCs and other materials from millions of refrigerators is a daunting challenge, but one in which utilities can play a leadership role. E Source believes that utilities can profitably serve as the catalyst for public-private partnerships that deliver comprehensive refrigerator recycling. Rather than treating such efforts solely as a DSM resource acquisition, utilities could position these programs as a multifaceted service delivery that offers convenient appliance removal for homeowners, a solid waste minimization service for landfills, a source of recycled materials for industry, and a CFC recovery and/or disposal service in support of the HVAC industry and society`s atmospheric protection goals and laws. Financial mechanisms could be developed through these public-private enterprises to ensure that utilities are compensated for the extra cost of fully recycling refrigerators, including the foam CFC.

Shepard, M.; Hawthorne, W.; Wilson, A.

1994-12-31

308

Analytical Investigation on Regenerative Magnetic Refrigeration with Particle Packed Bed  

NASA Astrophysics Data System (ADS)

Magnetic refrigeration is a cooling technology based on the magnetocaloric effect (MCE), which is a temperature-changing phenomenon caused under the magnetic field alteration. However, the temperature span caused by MCE is very small at room temperature. Hence Active Magnetic Regenerator (AMR) is developed to enhance temperature span of the system. In this paper, analytical evaluation and projection of cooling performance for magnetic refrigerator with AMR are conducted. An analytical model with bundle of small channels and jet flow and retention region in a test sectional tube is built in order to simulate fluid flow through spherical gadolinium particle packed bed as magneto caloric materials. The evaluation and projection of the AMR magnetic refrigeration system by analytical model showed performance of the temperature, and the existence of optimum operating conditions is shown under the condition of appropriate flow volume and volumetric flow rate.

Hirano, Shigeki; Kawanami, Tsuyoshi; Ikegawa, Masahiro; Fumoto, Koji; Hirasawa, Shigeki

309

MOBILE AIR CONDITIONER REFRIGERANT EVALUATION  

EPA Science Inventory

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

310

COLD STORAGE DESIGN REFRIGERATION EQUIPMENT  

E-print Network

COLD STORAGE DESIGN AND REFRIGERATION EQUIPMENT REFRIGERATION OF FISH - PART 1 \\ "..\\- ,,, T I Fishery Leaflet 427 Washington 25, D. C. June 1956 REFRIGERATION OF FISH - PART em; COlD STORAGE DESIGN (Section 1), and F. Bruce Sanford (Section 1) Table of Contents Pages Section 1 - Cold Storage Design

311

Exergy analysis of magnetic refrigeration  

E-print Network

One of the main challenges of the industry today is to face its impact on global warming considering that the greenhouse effect problem is not be solved completely yet. Magnetic refrigeration represents an environment-safe refrigeration technology. The magnetic refrigeration is analysed using the second law analysis and introducing exergy in order to obtain a model for engineering application.

Lucia, Umberto

2010-01-01

312

The vortex tube as a classic thermodynamic refrigeration cycle  

NASA Astrophysics Data System (ADS)

Vortex tubes are commonly used as refrigeration devices. We show that the thermal and fluid dynamics of the vortex tube bear the signature of a classic cooling cycle, and quantify its performance as a thermodynamic machine. In the process, we develop simple analytic formulas for the temperature and pressure profiles within the tube. The principal model predictions compare favorably against experimental measurements.

Ahlborn, Boye K.; Gordon, Jeffrey M.

2000-09-01

313

Inhomogeneous thermal conductivity enhances thermoelectric cooling  

NASA Astrophysics Data System (ADS)

We theoretically investigate the enhancement of thermoelectric cooling performance in thermoelectric refrigerators made of materials with inhomogeneous thermal conductivity, beyond the usual practice of enhancing thermoelectric figure of merit (ZT) of materials. The dissipation of the Joule heat in such thermoelectric refrigerators is asymmetric which can give rise to better thermoelectric cooling performance. Although the thermoelectric figure of merit and the coefficient-of-performance are slightly enhanced, both the maximum cooling power and the maximum cooling temperature difference can be enhanced significantly. This finding can be used to increase the heat absorption at the cold end. We further find that the asymmetric dissipation of Joule heat leads to thermal rectification.

Lu, Tingyu; Zhou, Jun; Li, Nianbei; Yang, Ronggui; Li, Baowen

2014-12-01

314

Education in Helium Refrigeration  

SciTech Connect

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

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

2004-06-23

315

Solar Powered Refrigeration System  

NASA Astrophysics Data System (ADS)

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

Ewert, Michael K.; Bergeron, David J., III

2002-09-01

316

Solar Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

317

On refrigerant compressors  

Microsoft Academic Search

The purpose of the work was to critically re-examine and investigate the evaluation of refrigerant compressors and to determine and discriminate between the factors which influence their characteristics. The objectives also included the investigation of techniques by which the characteristics can be established and the suggestion of ways in which compressor performance can be described and quantified. The particular compressor

Jim McGovern

1988-01-01

318

Heat powered refrigeration compressor  

NASA Astrophysics Data System (ADS)

This prototype will be of similar capacity as the compressor that will eventually be commercially produced. This unit can operate on almost any moderate temperature water heat source. This heat source could include such applications as industrial waste heat, solar, wood burning stove, resistance electrical heat produced by a windmill, or even perhaps heat put out by the condenser of another refrigeration system.

Goad, R. R.

319

An experimental analysis of cycling losses in domestic refrigerator-freezers  

SciTech Connect

This paper identifies and quantifies the cycling losses in a domestic refrigerator-freezer. During cycling operation the refrigerator was found to operate between 5% and 25% less efficiently than the corresponding quasi-steady machine. The cycling refrigerator operates with an evaporator capacity between 3% and 17% less than that of the quasi-steady refrigerator while at the same time requiring between 1% and 9% more power to operate. This refrigerator performance degradation was attributed to several factors, the most important being the refrigerant migration and the thermal mass of the evaporator and compressor. During the off-cycle, refrigerant migrates from the condenser to the evaporator as the system pressures equalize. The off-cycle migration increases the temperature of the evaporator and necessitates refrigerant redistribution during the on-cycle and thereby tends to reduce system performance. The increased power requirements, traced to the compressor, result from slight differences in system pressure and the reduced compressor efficiency due to a cool compressor. With the cycling losses identified, several possible refrigerator design changes were suggested. It appears that a refrigerator equipped with a reciprocating compressor, solenoid valves to isolate the condenser, and no accumulator should operate in a nearly quasi-steady manner.

Coulter, W.H. [DuPont Co., Belle, WV (United States); Bullard, C.W. [Univ. of Illinois, Urbana, IL (United States). Air Conditioning and Refrigeration Center

1997-12-31

320

76 FR 57612 - Energy Efficiency Program for Consumer Products: Test Procedures for Residential Refrigerators...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Residential Refrigerators, Refrigerator-Freezers, and Freezers AGENCY...residential refrigerators, refrigerator-freezers, and freezers that will...Residential Refrigerators, Refrigerator- Freezers, and Freezers'' and...

2011-09-15

321

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

322

Magnetic refrigeration apparatus with heat pipes  

DOEpatents

A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe of pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

Barclay, John A. (Los Alamos, NM); Prenger, Jr., F. Coyne (Madison, WI)

1987-01-01

323

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 Energy...COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Refrigerators, Freezers and Refrigerator-Freezers §...

2010-01-01

324

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

325

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

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2...Appendix A2 to Part 305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range...

2014-01-01

326

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

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2...Appendix A2 to Part 305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range...

2011-01-01

327

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

328

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

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2...Appendix A2 to Part 305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range...

2012-01-01

329

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

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2...Appendix A2 to Part 305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range...

2013-01-01

330

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

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Refrigerators and Refrigerators-Freezers With Manual Defrost A2 Appendix A2...Appendix A2 to Part 305—Refrigerators and Refrigerators-Freezers With Manual Defrost Range...

2010-01-01

331

Salt pill design and fabrication for adiabatic demagnetization refrigerators  

NASA Astrophysics Data System (ADS)

The performance of an adiabatic demagnetization refrigerator (ADR) is critically dependent on the design and construction of the salt pills that produce cooling. In most cases, the primary goal is to obtain the largest cooling capacity at the low temperature end of the operating range. The realizable cooling capacity depends on a number of factors, including refrigerant mass, and how efficiently it absorbs heat from the various instrument loads. The design and optimization of “salt pills” for ADR systems depend not only on the mechanical, chemical and thermal properties of the refrigerant, but also on the range of heat fluxes that the salt pill must accommodate. Despite the fairly wide variety of refrigerants available, those used at very low temperature tend to be hydrated salts that require a dedicated thermal bus and must be hermetically sealed, while those used at higher temperature - greater than about 0.5 K - tend to be single- or poly-crystals that have much simpler requirements for thermal and mechanical packaging. This paper presents a summary of strategies and techniques for designing, optimizing and fabricating salt pills for both low- and mid-temperature applications.

Shirron, Peter J.; McCammon, Dan

2014-07-01

332

Dry dilution refrigerator with 4He-1K-loop  

E-print Network

In this article we summarize experimental work on cryogen-free 3He/4He dilution refrigerators which, in addition to the dilution refrigeration circuit, are equipped with a 4He-1K-stage. This type of DR becomes worth considering when high cooling capacities are needed at T ~ 1 K to cool cold amplifiers and heat sink cables. In our application, the motivation for the construction of this type of cryostat was to do experiments on superconducting quantum circuits for quantum information technology and quantum simulations. In other work, DRs with 1K-stage were proposed for astro-physical cryostats. For neutron scattering research, a top-loading cryogen-free DR with 1K-stage was built which was equipped with a standard commercial dilution refrigeration insert. Cooling powers of up to 100 mW have been reached with our 1K-stage, but higher refrigeration powers were achieved with more powerful pulse tube cryocoolers and higher 4He circulation rates in the 1K-loop. Several different versions of a 1K-loop have been test...

Uhlig, Kurt

2014-01-01

333

Discussion of Refrigeration Cycle Using Carbon Dioxide as Refrigerant  

NASA Astrophysics Data System (ADS)

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

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

334

Flammability Indices for Refrigerants  

NASA Astrophysics Data System (ADS)

This paper introduces a new index to classify flammable refrigerants. A question on flammability indices that ASHRAE employs arose from combustion test results of R152a and ammonia. Conventional methods of not only ASHRAE but also ISO and Japanese High-pressure gas safety law to classify the flammability of refrigerants are evaluated to show why these methods conflict with the test results. The key finding of this paper is that the ratio of stoichiometric concentration to LFL concentration (R factor) represents the test results most precisely. In addition, it has excellent correlation with other flammability parameters such as flame speed and pressure rise coefficient. Classification according to this index gives reasonable flammability order of substances including ammonia, R152a and carbon monoxide. Theoretical background why this index gives good correlation is also discussed as well as the insufficient part of this method.

Kataoka, Osami

335

Refrigerants in Transition  

E-print Network

ozone layer, resulting in harm to human health and the environment. LEGISLATIVE ACTION As a result of recogn~z~ng that these con cerns were of a global nature, an international meeting was held in Montreal, Canada. A document, called the Montreal.... Table I. Comparison of Selected Refrigerants Refrigerant Ozone Depletion Global Warming Potential Potential CFC-l1 1.0 1.0 CFC-12 1.0 3.1 CFC-113 0.8 1.4 * CFC-114 1.0 3.9 * CFC-115 0.6 7.6 * HCFC-22 0.05 0.35 HCFC-123 0.02 0.02 HCFC-124 0.02 0...

Stouppe, D. E.

336

APPLIANCE EFFICIENCY REGULATIONS FOR REFRIGERATORS AND FREEZERS  

E-print Network

#12;#12;APPLIANCE EFFICIENCY REGULATIONS FOR REFRIGERATORS AND FREEZERS ROOM AIR CONDITIONERS sold in California: (a) Refrigerators, refrigerator-freezers, and freezers which can be operated in recreational vehicles and other mobile equipment; (2) those refrigerators and refrigerator-freezers with total

337

Instability of refrigeration system – A review  

Microsoft Academic Search

It is essential to ensure the stability for the normal operation of refrigeration systems. This paper reviews the researches on the theory and solutions of the instability of refrigeration systems. The instability of refrigeration systems includes two aspects: the two-phase flow instability in refrigeration system, the instability on refrigeration system control characteristics. As an inherent characteristic of two-phase evaporating flow,

Nan Liang; Shuangquan Shao; Hongbo Xu; Changqing Tian

2010-01-01

338

Refrigeration and Food Safety  

MedlinePLUS

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

339

Reduction of Thermal Energy Loss in Cyclic Operation of Refrigeration Cycle  

NASA Astrophysics Data System (ADS)

Investigation of thermal energy loss in cyclic operation of refrigeration cycle in a refrigerator-freezer were made. The energy loss was found to consist of three parts ; hot gas-refrigerant entering loss, cooling lag loss, and evaporator superheat loss. Hot gas-refrigerant entering loss is occured when high temperature gaseous refrigerant in a condenser flows into an evaporator to heat up the refrigerant in it. Main results are as follows ; 1) Hot gas-refrigerant entering loss, which was the most dominant, was found to be from 7.6 to 12.3% (for reciprocationg compressor) and from 11.9 to 17.4% (for rotary compressor) of the cooling load, respectively. 2) The thermal energy loss was confirmed to be able to be reduced when hot gas-refrigerant was restricted to flow in the evaporator with control valves. It follows to reduce electrical power consumption by 10 and 15%, in the case of reciprocating compressor and of rotary compressor, respectively. 3) Cycle frequency was made to be optimized theoretically and experimentally in the case of with and without valves.

Gommori, Masahiko; Kogure, Hiroshi; Hara, Toshitsugu

340

Vaccine refrigerator testing. Final report  

SciTech Connect

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

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

1990-06-01

341

On optimum interstage pressure for two-stage and mechanical-subcooling vapor-compression refrigeration cycles  

Microsoft Academic Search

The objective of the present study is to demonstrate that the optimum interstage pressure for a two-stage refrigeration system can be approximated by the saturation pressure corresponding to the arithmetic mean of the condensing and evaporating temperatures. It is also shown that the optimum performance of a refrigeration system with mechanical sub-cooling occurred when the subcooler compressor (saturation suction) temperature

S. M. Zubair; S. H. Khan

1995-01-01

342

Japanese activities in refrigeration technology  

NASA Astrophysics Data System (ADS)

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

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

343

The HAWC and SAFIRE adiabatic demagnetization refrigerators  

NASA Astrophysics Data System (ADS)

High-resolution airborne wide-band camera (HAWC) and sub-millimeter and far-infrared experiment (SAFIRE) are far-infrared experiments which will fly on the stratospheric observatory for infrared astronomy (SOFIA) aircraft. HAWC's detectors will operate at 0.2 K, while those of SAFIRE will be at 0.1 K. Each instrument will include an adiabatic demagnetization refrigerator (ADR) to cool its detector stage from the liquid helium bath temperature (HAWC's at 4.2 K and SAFIRE's pumped to about 1.3 K) to its operating temperature. Except for the magnets used to achieve the cooling, the magnetic shielding, and a slight difference in the heat switch design, the two ADRs are identical. We describe the ADR design and present the results of performance testing.

Tuttle, Jim; Shirron, Peter; DiPirro, Michael; Jackson, Michael; Behr, Jason; Kamiya, Koji; Warner, Brent; Kunes, Evan; Hait, Tom

2001-11-01

344

The HAWC and SAFIRE Adiabatic Demagnetization Refrigerators  

NASA Technical Reports Server (NTRS)

The High-Resolution Airborne Wide-band Camera (HAWC) and Submillimeter and Far Infrared Experiment (SAFIRE) are far-infrared experiments which will fly on the Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft. HAWC's detectors will operate at 0.2 Kelvin, while those of SAFIRE will be at 0.1 Kelvin. Each instrument will include an adiabatic demagnetization refrigerator (ADR) to cool its detector stage from the liquid helium bath temperature (HAWC's at 4.2 Kelvin and SAFIRE's pumped to about 1.3 Kelvin) to its operating temperature. Except for the magnets used to achieve the cooling and a slight difference in the heat switch design, the two ADRs are nearly identical. We describe the ADR design and present the results of performance testing.

Tuttle, Jim; Shirron, Peter; DiPirro, Michael; Jackson, Michael; Behr, Jason; Kunes, Evan; Hait, Tom; Krebs, Carolyn (Technical Monitor)

2001-01-01

345

Modeling and Control of a Double-effect Absorption Refrigerating Machine  

NASA Astrophysics Data System (ADS)

Because the heat capacity of absorption refrigerating machines is large compared with vapor compression refrigerating machines, the dynamic characteristics at the change in cooling load conditions are problems to be improved. The control method of energy input and of weak solution flow rate following cooling load variations was investigated. As the changes in cooling load and cooling capacity are moderate, the optimal operation conditions corresponding to the cooling load can be estimated with steady state characteristics. If the relation between the cooling load and the optimal operation conditions is well known, a feed forward control can be employed. In this report a new control algorithm, which is called MOL (Multi-variable Open Loop) control, is proposed. Comparing the MOL control with the conventional chilled water outlet temperature proportional control, the MOL control enables the smooth changes in cooling capacity and the reduction in fuel consumption.

Hihara, Eiji; Yamamoto, Yuuji; Saito, Takamoto; Nagaoka, Yoshikazu; Nishiyama, Noriyuki

346

63 FR 58767 - Refrigeration Compressors From Singapore  

Federal Register 2010, 2011, 2012, 2013, 2014

...701-TA-B (Review)] Refrigeration Compressors From Singapore AGENCY: United States...suspended investigation on refrigeration compressors from Singapore...suspended investigation on refrigeration compressors from Singapore would be likely to...

1998-11-02

347

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Refrigerating machines. 173.174 Section 173.174 Transportation...Class 1 and Class 7 § 173.174 Refrigerating machines. A refrigerating machine assembled for shipment and containing 7 kg...

2012-10-01

348

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

349

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Refrigerating machines. 173.174 Section 173.174 Transportation...Class 1 and Class 7 § 173.174 Refrigerating machines. A refrigerating machine assembled for shipment and containing 7 kg...

2013-10-01

350

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Refrigerating machines. 173.174 Section 173.174 Transportation...Class 1 and Class 7 § 173.174 Refrigerating machines. A refrigerating machine assembled for shipment and containing 7 kg...

2014-10-01

351

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

352

THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS  

EPA Science Inventory

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

353

PROJECT REPORT WESTERN COOLING CHALLENGE LABORATORY  

E-print Network

-cool- er to reduce the refrigerant condensing temperature of a vapor compression system, then cycles of conventional vapor compression sys- tems, the laboratory results documented herein demonstrate that 40% peak conditioner that inte- grates the DualCoolTM with an otherwise conventional vapor com- pression system

California at Davis, University of

354

Life test results of hydride compressors for cryogenic refrigerators  

NASA Technical Reports Server (NTRS)

A development status assessment is made, from the viewpoint of system durability, for the hydride compressors used in such cryogenic refrigerators as that of the JPL, which has operated at 29 K for 500 hours and at lower temperatures for over 1000. Attention is given to a novel hydride compressor unit which has operated through 35,000 cycles and exhibits negligible degradation of check valves, hydride particle size, and expansion valves. The power requirement for liquid hydrogen cooling can be halved through the use of recuperative hot water heating methods, making this system comparable in power use to liquid hydrogen refrigeration systems operating on electricity. Due to the lack of moving parts in hydride refrigerator designs, potential service lifetimes of many years, and perhaps decades, are being projected.

Jones, J. A.; Golben, P. M.

1984-01-01

355

Development of New Refrigeration Circuit to Control Refrigerant Mixture Composition  

NASA Astrophysics Data System (ADS)

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

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

356

Design of a single orifice pulse tube refrigerator through the development of a first-order model  

E-print Network

A first order model for the behavior of a linear orifice pulse tube refrigerator (OPTR) was developed as a design tool for construction of actual OPTRs. The model predicts cooling power as well as the pressure/volume ...

Schor, Alisha R. (Alisha Robin)

2007-01-01

357

The refrigerator revolution  

SciTech Connect

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

Ayres, E.; French, H.

1996-09-01

358

Cycling Joule Thomson refrigerator  

NASA Astrophysics Data System (ADS)

A symmetrical adsorption pump/compressor system having a pair of mirror image legs and a Joule Thomson expander, or valve, interposed between the legs thereof for providing a, efficient refrigeration cycle is described. The system further includes a plurality of gas operational heat switches adapted selectively to transfer heat from a thermal load and to transfer or discharge heat through a heat projector, such as a radiator or the like. The heat switches comprise heat pressurizable chambers adapted for alternate pressurization in response to adsorption and desorption of a pressurizing gas confined therein.

Tward, E.

1983-01-01

359

Life test performance of a Philips rhombic-drive refrigerator with bellows seals  

NASA Technical Reports Server (NTRS)

In February 1979, tour Stirling cycle cryogenic refrigerators, developed by Philips Laboratories for the John Hopkins University/Applied Physics Laboratory, were launched into orbit aboard the P78-1 spacecraft. The refrigerators were designed to cool the detectors of two identical gamma-ray spectrometers to 77 K reliably for one year. Since launch, the refrigerators, still in orbit, have individually accumulated from 5,000 to over 20,000 hours of operation. As part of those efforts, a refrigerator identical to those in orbit was built, with one significant modification: flexible metal bellows between the crankcase and the working volume to prevent possible contaminants from migrating into the cold region. During the life test of the modified refrigerator, the temperature increase during the first three month run was 0.022 k/day, a negligible level. As of October 1982, the unit has accumulated over 12,300 hours of operation.

Lindale, E.; Lehrfeld, D.

1983-01-01

360

Development of a refrigeration system for lunar surface and spacecraft applications  

NASA Technical Reports Server (NTRS)

An evaluation of refrigeration devices suitable for potential lunar surface and spacecraft applications was performed. The following conclusions were reached: (1) the vapor compression system is the best overall refrigeration system for lunar surface and spacecraft applications and the single phase radiator system is generally preferred for earth orbit applications, (2) the vapor compression cycle may have some application for simultaneous heating and cooling, (3) a Stirling cycle refrigerator was selected for the manned cabin of the space shuttle, and (4) significant increases in payload heat rejection can be obtained by a kit vapor compression refrigerator added to the shuttle R-21 loop. The following recommendations were made: (1) a Stirling cycle refrigerator may be used for food freezer and biomedical sample storage, (2) the best system for a food freezer/experiments compartment for an earth orbit space station has not been determined, (3) a deployed radiator system can be designed for large heat loads in earth orbit.

Copeland, R. J.

1976-01-01

361

The Effects of Internal and External Irreversibility of a Vapor Compression Refrigeration Cycle  

NASA Astrophysics Data System (ADS)

The concept of finite-time thermodynamics is employed to investigate the optimal refrigeration rate for an irreversible refrigeration cycle. The heat transfer between the system (internal) fluid and cooling (external) fluid takes place at the actual heat exchanger, which has the finite-size heat transfer area and the realistic heat transfer effectiveness. The internal irreversibility results from the compression process and the expansion process are also considered. The optimal refrigeration rate is calculated and expressed in terms of the irreversibility parameter (Ir), coefficient of performance (COP), the time ratio(?) of heat transfer processes and the effectiveness of heat exchanger. The derived COP which consider both the external and internal irreversibility can thus be considered as the benchmark value for a practical refrigeration cycle, and the parametric study can provide the basis for both determination of optimal operating conditions and design of a practical refrigeration cycle.

Wang, Fu-Jen; Chiou, Jeng-Shing

362

Superinsulation in refrigerators and freezers  

Microsoft Academic Search

The results presented here were obtained during Phase 4 of the first CRADA, which had the specific objective of determining the lifetime of superinsulations when installed in simulated refrigerator doors. The second CRADA was established to evaluate and test design concepts proposed to significantly reduce energy consumption in a refrigerator-freezer that is representative of approximately 60% of the US market.

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

1998-01-01

363

Triple loop heat exchanger for an absorption refrigeration system  

DOEpatents

A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

Reimann, Robert C. (Lafayette, NY)

1984-01-01

364

A closed-cycle 1 K refrigeration cryostat  

NASA Astrophysics Data System (ADS)

A 1 K closed-cycle cryostat has been developed to provide continuous cooling to a photon detector below 2 K. A two-stage 4 K pulse tube cryocooler is used to liquefy evacuated vapor from a 1 K pumping port to form a closed-cycle refrigeration loop. A 1 K instrumentation chamber, attached to the 1 K cooling station, is designed to operate with helium inside and provide more uniform cooling. The design of the cryostat has no direct mechanical contact between the pulse tube cryocooler heat exchangers and the 1 K cooling station resulting in almost no vibration transfer to instrumentation chamber. The cryostat can reach a no-load temperature of 1.62 K and provide 250 mW cooling power at 1.84 K.

Wang, Chao; Lichtenwalter, Ben; Friebel, Aaron; Tang, Hong X.

2014-11-01

365

Fractional watt Vuillemier cryogenic refrigerator program engineering notebook. Volume 2: Stress analysis  

NASA Technical Reports Server (NTRS)

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 structurally loaded refrigerator components shown in assembly drawings. The stress analysis indicates that the design is satisfactory for the specified vibration environment, and the proof, burst, and normal operating loads.

Miller, W. S.

1974-01-01

366

Optimal performance of reciprocating demagnetization quantum refrigerators  

NASA Astrophysics Data System (ADS)

A reciprocating quantum refrigerator is studied with the purpose of determining the limitations of cooling to absolute zero. The cycle is based on demagnetization and magnetization of a working medium. We find that if the energy spectrum of the working medium possesses an uncontrollable gap, and in addition there is noise on the controls, then there is a minimum achievable temperature above zero. The reason is that even a negligible amount of noise prevents adiabatic following during the demagnetization stage. This results with a minimum temperature, Tc(min)>0 , which scales with the energy gap. The refrigerator is based on an Otto cycle where the working medium is an interacting spin system with an energy gap. For this system the external control Hamiltonian does not commute with the internal interaction. As a result during the demagnetization and magnetization segments of the operating cycle the system cannot follow adiabatically the temporal change in the energy levels. We connect the nonadiabatic dynamics to quantum friction. An adiabatic measure is defined characterizing the rate of change of the Hamiltonian. Closed-form solutions are found for a constant adiabatic measure for all the cycle segments. We have identified a family of quantized frictionless cycles with increasing cycle times. These cycles minimize the entropy production. Such frictionless cycles are able to cool to Tc=0 . External noise on the controls eliminates these frictionless cycles. The influence of phase and amplitude noise on the demagnetization and magnetization segments is explicitly derived. An extensive numerical study of optimal cooling cycles was carried out which showed that at sufficiently low temperature the noise always dominated restricting the minimum temperature.

Kosloff, Ronnie; Feldmann, Tova

2010-07-01

367

Refrigeration system with a compressor-pump unit and a liquid-injection desuperheating line  

DOEpatents

The refrigeration system includes a compressor-pump unit and/or a liquid-injection assembly. The refrigeration system is a vapor-compression refrigeration system that includes an expansion device, an evaporator, a compressor, a condenser, and a liquid pump between the condenser and the expansion device. The liquid pump improves efficiency of the refrigeration system by increasing the pressure of, thus subcooling, the liquid refrigerant delivered from the condenser to the expansion device. The liquid pump and the compressor are driven by a single driving device and, in this regard, are coupled to a single shaft of a driving device, such as a belt-drive, an engine, or an electric motor. While the driving device may be separately contained, in a preferred embodiment, the liquid pump, the compressor, and the driving device (i.e., an electric motor) are contained within a single sealable housing having pump and driving device cooling paths to subcool liquid refrigerant discharged from the liquid pump and to control the operating temperature of the driving device. In another aspect of the present invention, a liquid injection assembly is included in a refrigeration system to divert liquid refrigerant from the discharge of a liquid pressure amplification pump to a compressor discharge pathway within a compressor housing to desuperheat refrigerant vapor to the saturation point within the compressor housing. The liquid injection assembly includes a liquid injection pipe with a control valve to meter the volume of diverted liquid refrigerant. The liquid injection assembly may also include a feedback controller with a microprocessor responsive to a pressure sensor and a temperature sensor both positioned between the compressor to operate the control valve to maintain the refrigerant at or near saturation.

Gaul, Christopher J. (Thornton, CO)

2001-01-01

368

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

Microsoft Academic Search

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

Da-Wen Sun

1999-01-01

369

Refrigerator: Refrigerators and freezers are not typically constructed to assure that there is no  

E-print Network

LAB SAFETY Refrigerator: Refrigerators and freezers are not typically constructed to assure temperature of the refrigerator rises. This results in an increase in the concentration of flammable vapors within the refrigerator's interior. When power is restored, a spark generated by the refrigerator light

Cohen, Robert E.

370

77 FR 7547 - Energy Conservation Standards for Wine Chillers and Miscellaneous Refrigeration Products: Public...  

Federal Register 2010, 2011, 2012, 2013, 2014

...standards/residential/refrigerators_freezers.html. DATES: DOE will...standards for refrigerators, refrigerator-freezers, and freezers (residential...1) Refrigerators and refrigerator-freezers with manual...

2012-02-13

371

Synopsis of residential refrigerator/freezer alternative refrigerants evaluation  

SciTech Connect

The experimental testing on residential refrigerator/freezers (R/Fs) is summarized in this paper. R/F testing focused on two areas: alternative refrigerants and equipment configurations. The refrigerants evaluated consisted of single components, azeotropes, and zeotropes derived from hydrofluorocarbons (HFCs) and hydrocarbons (HCs). These refrigerants were evaluated in conventional and unconventional R/F designs. Major and minor design modifications were studied. Minor modifications consisted of various capillary tube lengths, door insulations, and compressors, while major modifications included two-evaporator and two-cycle R/F systems. Results obtained from testing the two-cycle system will be discussed in a later paper. This paper presents the experimental results of alternative technologies evaluated as replacements for ozone depleting chemicals.

Baskin, E. [Environmental Protection Agency, Research Triangle Park, NC (United States)

1998-12-31

372

Refrigerator-freezer energy testing with alternative refrigerants  

Microsoft Academic Search

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

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

1989-01-01

373

Heat pump system with selective space cooling  

DOEpatents

A reversible heat pump provides multiple heating and cooling modes and includes a compressor, an evaporator and heat exchanger all interconnected and charged with refrigerant fluid. The heat exchanger includes tanks connected in series to the water supply and a condenser feed line with heat transfer sections connected in counterflow relationship. The heat pump has an accumulator and suction line for the refrigerant fluid upstream of the compressor. Sub-cool transfer tubes associated with the accumulator/suction line reclaim a portion of the heat from the heat exchanger. A reversing valve switches between heating/cooling modes. A first bypass is operative to direct the refrigerant fluid around the sub-cool transfer tubes in the space cooling only mode and during which an expansion valve is utilized upstream of the evaporator/indoor coil. A second bypass is provided around the expansion valve. A programmable microprocessor activates the first bypass in the cooling only mode and deactivates the second bypass, and vice-versa in the multiple heating modes for said heat exchanger. In the heating modes, the evaporator may include an auxiliary outdoor coil for direct supplemental heat dissipation into ambient air. In the multiple heating modes, the condensed refrigerant fluid is regulated by a flow control valve.

Pendergrass, Joseph C. (Gainesville, GA)

1997-01-01

374

Heat pump system with selective space cooling  

DOEpatents

A reversible heat pump provides multiple heating and cooling modes and includes a compressor, an evaporator and heat exchanger all interconnected and charged with refrigerant fluid. The heat exchanger includes tanks connected in series to the water supply and a condenser feed line with heat transfer sections connected in counterflow relationship. The heat pump has an accumulator and suction line for the refrigerant fluid upstream of the compressor. Sub-cool transfer tubes associated with the accumulator/suction line reclaim a portion of the heat from the heat exchanger. A reversing valve switches between heating/cooling modes. A first bypass is operative to direct the refrigerant fluid around the sub-cool transfer tubes in the space cooling only mode and during which an expansion valve is utilized upstream of the evaporator/indoor coil. A second bypass is provided around the expansion valve. A programmable microprocessor activates the first bypass in the cooling only mode and deactivates the second bypass, and vice-versa in the multiple heating modes for said heat exchanger. In the heating modes, the evaporator may include an auxiliary outdoor coil for direct supplemental heat dissipation into ambient air. In the multiple heating modes, the condensed refrigerant fluid is regulated by a flow control valve. 4 figs.

Pendergrass, J.C.

1997-05-13

375

Experimental Investigations on the Characteristics of the Ammonia-Water Absorption Refrigerator for Low Temperature Solution Cycle  

NASA Astrophysics Data System (ADS)

This report refers to some static characteristics of the ammonia-water absorption refrigerator for low temperature refrigerating process which needs the temperature below the freezing point. Especially, the influence of evaporating temperature and cooling water temperature is clarified by the experimental investigation. In addition to this, the validity of constructed simulation model of this absorption refrigerator is mentioned. The validity of simulation model is verified by the comparison of experimental results and calculation. To examine the characteristics, we conducted the performance test using the trial product of which the standard cooling capacity is 175kW. The performance is estimated according to cooling capacity and COP. As a result, the effects of the evaporating temperature and cooling water temperature on the cooling performance are clarified by the experimental research. Furthermore, the calculation of the static characteristics predicted by the simulation model is in good agreements with the experimental results.

Takei, Toshitaka; Kimijima, Shinji; Saito, Kiyoshi; Kawai, Sunao

376

Investigation on the internal thermal link of pulse tube refrigerators  

NASA Astrophysics Data System (ADS)

Within a pulse tube refrigerator (PTR) in coaxial configuration the pulse tube is located inside the regenerator matrix in axial direction. An internal thermal contact between these two main components of the coldfinger occurs. The experimental investigation of the direction and the quantity of transferred heat is in focus of this paper. Intermediate cooling of the regenerator by the corresponding part of its own pulse tube can improve the cooling performance of a PTR. Therefore, a well-adapted geometrical arrangement between the pulse tube and the regenerator is essential, considering the temperature distribution inside the coldfinger. We deduce design parameters to optimise the configuration of coaxial PTRs.

Koettig, T.; Moldenhauer, S.; Patze, M.; Thürk, M.; Seidel, P.

2007-03-01

377

Energy Efficient, Environmentally Friendly Refrigerants  

E-print Network

This paper describes a new family of safe, environmentally friendly, high performance substitute refrigerants for application in manufacturing and facilities operations. Due to the Montreal Protocol and subsequent environmental regulations, CFC...

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

378

Final Scientific/Technical Report for DOE/EERE project Advanced Magnetic Refrigerant Materials  

SciTech Connect

A team led by GE Global Research developed new magnetic refrigerant materials needed to enhance the commercialization potential of residential appliances such as refrigerators and air conditioners based on the magnetocaloric effect (a nonvapor compression cooling cycle). The new magnetic refrigerant materials have potentially better performance at lower cost than existing materials, increasing technology readiness level. The performance target of the new magnetocaloric material was to reduce the magnetic field needed to achieve 4 °C adiabatic temperature change from 1.5 Tesla to 0.75 Tesla. Such a reduction in field minimizes the cost of the magnet assembly needed for a magnetic refrigerator. Such a reduction in magnet assembly cost is crucial to achieving commercialization of magnetic refrigerator technology. This project was organized as an iterative alloy development effort with a parallel material modeling task being performed at George Washington University. Four families of novel magnetocaloric alloys were identified, screened, and assessed for their performance potential in a magnetic refrigeration cycle. Compositions from three of the alloy families were manufactured into regenerator components. At the beginning of the project a previously studied magnetocaloric alloy was selected for manufacturing into the first regenerator component. Each of the regenerators was tested in magnetic refrigerator prototypes at a subcontractor at at GE Appliances. The property targets for operating temperature range, operating temperature control, magnetic field sensitivity, and corrosion resistance were met. The targets for adiabatic temperature change and thermal hysteresis were not met. The high thermal hysteresis also prevented the regenerator components from displaying measurable cooling power when tested in prototype magnetic refrigerators. Magnetic refrigerant alloy compositions that were predicted to have low hysteresis were not attainable with conventional alloy processing methods. Preliminary experiments with rapid solidification methods showed a path towards attaining low hysteresis compositions should this alloy development effort be continued.

Johnson, Francis

2014-06-30

379

Inert hydrocarbon-based refrigerants  

Microsoft Academic Search

This paper determines the flammability properties of two hydrocarbon blends, natural gas and propane–butane refrigerant, mixed with CF3I and C3F7H inerting agents. Four flammability envelopes are obtained allowing the determination of the minimum inerting concentrations and the maximum hydrocarbon to suppressant weight ratios for formulating non-flammable hydrocarbon refrigerants. These ratios are calculated from the slopes of lines drawn from the

B. Z. Dlugogorski; R. K. Hichens; E. M. Kennedy

2002-01-01

380

Bipolar pulse field for magnetic refrigeration  

DOEpatents

A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies.

Lubell, Martin S. (Oak Ridge, TN)

1994-01-01

381

Entanglement enhances cooling in microscopic quantum fridges  

E-print Network

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

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

2014-03-14

382

Sub-cooled liquid helium flow supply for design D magnet cooling at MDTF. [Magnet Development and Test Facility  

SciTech Connect

The parameters of the subcooled 4ATM helium flow from MTDF refrigerator and helium subcooler proposed to cool the SSC Design 'D' magnet is discussed. The system operating parameters are pressure - 4ATM and temperature - 4.35K. The higher than normal operating pressure is obtained by shutting down the cold turbine (T2) of MTDF refrigerator, and then not J-T the high pressure dense helium gas until after the magnet and liquid return line. The resultant helium temperature at the refrigerator outlet is described and the heat transfer tube length of the subcooler required to cool the flow to the ultimate desired temperature is evaluated.

Ohmori, T.

1986-07-01

383

Development of a Battery-Free Solar Refrigerator  

NASA Technical Reports Server (NTRS)

Recent technology developments and a systems engineering design approach have led to the development of a practical battery-free solar refrigerator as a spin-off of NASA's aerospace refrigeration research. Off-grid refrigeration is a good application of solar photovoltaic (PV) power if thermal storage is incorporated and a direct connection is made between the cooling system and the PV panel. This was accomplished by integrating water as a phase-change material into a well insulated refrigerator cabinet and by developing a microprocessor based control system that allows direct connection of a PV panel to a variable speed compressor. This second innovation also allowed peak power-point tracking from the PV panel and elimination of batteries from the system. First a laboratory unit was developed to prove the concept and then a commercial unit was produced and deployed in a field test. The laboratory unit was used to test many different configurations including thermoelectric, Stirling and vapor compression cooling systems. The final configuration used a vapor compression cooling cycle, vacuum insulation, a passive condenser, an integral evaporator/ thermal storage tank, two 77 watt PV panels and the novel controller mentioned above. The system's only moving part was the variable speed BD35 compressor made by Danfoss. The 365 liter cabinet stayed cold with as little as 274 watt-hours per day average PV power. Battery-free testing was conducted for several months with very good results. The amount of thermal storage, size of compressor and power of PV panels connected can all be adjusted to optimize the design for a given application and climate. In the commercial unit, the high cost of the vacuum insulated refrigerator cabinet and the stainless steel thermal storage tank were addressed in an effort to make the technology commercially viable. This unit started with a 142 liter, mass-produced chest freezer cabinet that had the evaporator integrated into its inner walls. Its compressor was replaced with a Danfoss DC compressor slightly larger than the one used in the laboratory unit. The control system was integrated onto a single electronics card and packaged with its starting capacitors. The water for thermal storage was placed behind a liner that was made to fit inside the original factory liner. The original condenser was also augmented with additional surface area to improve performance. PV panels with a total rated power of 180 watts were used. The unit was tested with very successful results in an outside ambient environment, demonstrating its potential for widespread use in many off-grid applications for solar refrigeration.

Ewert, Michael K.; Bergeron, David J., III

2000-01-01

384

U.S. Residential Miscellaneous Refrigeration Products: Results from Amazon Mechanical Turk Surveys  

SciTech Connect

Amazon Mechanical Turk was used, for the first time, to collect statistically representative survey data from U.S. households on the presence, number, type and usage of refrigerators, freezers, and various “miscellaneous” refrigeration products (wine/beverage coolers, residential icemakers and non-vapor compression refrigerators and freezers), along with household and demographic information. Such products have been poorly studied to date, with almost no information available about shipments, stocks, capacities, energy use, etc. A total of 9,981 clean survey responses were obtained from five distinct surveys deployed in 2012. General refrigeration product survey responses were weighted to demographics in the U.S. Energy Information Administration’s Residential Energy Consumption Survey 2009 dataset. Miscellaneous refrigeration product survey responses were weighted according to demographics of product ownership found in the general refrigeration product surveys. Model number matching for a portion of miscellaneous refrigeration product responses allowed validation of refrigeration product characteristics, which enabled more accurate estimates of the penetrations of these products in U.S. households. We estimated that there were 12.3±1.0 million wine/beverage coolers, 5.5(–3.5,+3.2) million residential icemakers and 4.4(–2.7,+2.3) million non-vapor compression refrigerators in U.S. households in 2012. (All numerical results are expressed with ranges indicating the 95% confidence interval.) No evidence was found for the existence of non-vapor compression freezers. Moreover, we found that 15% of wine/beverage coolers used vapor compression cooling technology, while 85% used thermoelectric cooling technology, with the vast majority of thermoelectric units having capacities of less than 30 wine bottles (approximately 3.5 cubic feet). No evidence was found for the existence of wine/beverage coolers with absorption cooling technology. Additionally, we estimated that there were 3.6±1.0 million hybrid refrigerator-wine/beverage coolers and 0.9±0.5 million hybrid freezer-wine/beverage coolers in U.S. households. We also obtained estimates of miscellaneous refrigeration product capacities, lifetimes, purchase and installation costs, repair frequencies and costs, and maintenance costs. For wine/beverage coolers, we also obtained information on the penetration of built-in units, AC/DC operating capability, the use of internal lights, and distributions of door opening frequencies. This information is essential to develop detailed estimates of national energy usage and life-cycle costs, and would be helpful in obtaining information on other plug-load appliances. Additional information not highlighted in the main report was presented in Appendices.

Greenblatt, Jeffery B.; Young, Scott J.; Yang, Hung-Chia; Long, Timothy; Beraki, Bereket; Price, Sarah K.; Pratt, Stacy; Willem, Henry; Desroches, Louis-Benoit

2013-11-14

385

Scaling and Optimization of Magnetic Refrigeration for Commercial Building HVAC Systems Greater than 175 kW in Capacity  

SciTech Connect

Heating, ventilation, air-conditioning and refrigeration (HVACR) account for approximately one- third of building energy consumption. Magnetic refrigeration presents an opportunity for significant energy savings and emissions reduction for serving the building heating, cooling, and refrigeration loads. In this paper, we have examined the magnet and MCE material requirements for scaling magnetic refrigeration systems for commercial building cooling applications. Scaling relationships governing the resources required for magnetic refrigeration systems have been developed. As system refrigeration capacity increases, the use of superconducting magnet systems becomes more applicable, and a comparison is presented of system requirements for permanent and superconducting (SC) magnetization systems. Included in this analysis is an investigation of the ability of superconducting magnet based systems to overcome the parasitic power penalty of the cryocooler used to keep SC windings at cryogenic temperatures. Scaling relationships were used to develop the initial specification for a SC magnet-based active magnetic regeneration (AMR) system. An optimized superconducting magnet was designed to support this system. In this analysis, we show that the SC magnet system consisting of two 0.38 m3 regenerators is capable of producing 285 kW of cooling power with a T of 28 K. A system COP of 4.02 including cryocooler and fan losses which illustrates that an SC magnet-based system can operate with efficiency comparable to traditional systems and deliver large cooling powers of 285.4 kW (81.2 Tons).

Abdelaziz, Omar [ORNL] [ORNL; West, David L [ORNL] [ORNL; Mallow, Anne M [ORNL] [ORNL

2012-01-01

386

COFELY Refrigeration | Rdiger Roth | European Heat Pump Summit 2013 CopyrightCOFELYDeutuschlandGmbH2009.AlleRechtevorbehalten.  

E-print Network

and freezing) Hotels (cooling and water heating) Swimming pools (dehumification and water heating) Hospitals performance finned tubes · High heat transfer efficiency Integrated open flash economizer · Increase (cooling, floor heating, water heating) Ice stores #12;COFELY Refrigeration | Rüdiger Roth | European Heat

Oak Ridge National Laboratory

387

Modelling of a refrigerating system coupled with a refrigerated room  

NASA Astrophysics Data System (ADS)

The development of a set of comprehensive computer models to simulate and analyze both steady state and non steady state behavior of a refrigerating system coupled with a refrigerated room is described. The refrigerating system is a single stage vapor compression system consisting of four basic elements: a reciprocating piston compressor, a dry expansion evaporator (or cooler), a shell and tube watercooled condensor and a thermostatic expansion valve. To validate the computer models, a test plant on which steady state and dynamic measurements were carried out, was set up. Experiments to determine several empirical constants encountered in the models were done, and the simulation results were compared with a series of measurements within a wide range of operation conditions. The validated models were applied to the prediction of the air distributions in a cold store and the study of a system with different capacity control systems, proving the capability and reliability of the models.

Wang, Hongwei

1991-08-01

388

Investigation on the Room Temperature Active Magnetic Regenerative Refrigerator with Permanent Magnet Array  

NASA Astrophysics Data System (ADS)

In this study, a room temperature active magnetic regenerative refrigerator is investigated experimentally as well as numerically. Gadolinium is selected as a magnetic refrigerant. A permanent magnet array, so called Halbach array, is employed to produce strong magnetic field. The AMR (Active Magnetic Regenerator) is reciprocated through the bore of the magnet array and produces cooling power. Helium is supplied by a helium compressor equipped with a rotary valve. Although the refrigeration effect is generated due to the pressure fluctuation of the helium flow, the enhancement of refrigeration by the magnetocaloric effect can be observed. One dimensional numerical simulation for the AMR is established. Measured mass flow rate, inlet temperature and pressure fluctuation are used as boundary conditions, and the calculated temperature distribution during the steady state is compared with the measured one. The model and the numerical simulation in this paper will be a useful tool for prediction of AMR's performance and investigation of the internal state of AMR.

Kim, Y.; Jeong, S.

2010-04-01

389

Dry demagnetization cryostat for sub-millikelvin helium experiments: refrigeration and thermometry.  

PubMed

We demonstrate successful "dry" refrigeration of quantum fluids down to T = 0.16 mK by using copper nuclear demagnetization stage that is pre-cooled by a pulse-tube-based dilution refrigerator. This type of refrigeration delivers a flexible and simple sub-mK solution to a variety of needs including experiments with superfluid (3)He. Our central design principle was to eliminate relative vibrations between the high-field magnet and the nuclear refrigeration stage, which resulted in the minimum heat leak of Q = 4.4 nW obtained in field of 35 mT. For thermometry, we employed a quartz tuning fork immersed into liquid (3)He. We show that the fork oscillator can be considered as self-calibrating in superfluid (3)He at the crossover point from hydrodynamic into ballistic quasiparticle regime. PMID:25173311

Todoshchenko, I; Kaikkonen, J-P; Blaauwgeers, R; Hakonen, P J; Savin, A

2014-08-01

390

Study on scroll compressor behavior in case of liquid refrigerant injectio  

NASA Astrophysics Data System (ADS)

Scroll compressors have excellent fundamental features such as high efficiency, high reliability, low vibration and low noise, so scroll compressors have been recently used to heat pump and automotive air conditioners. Furthermore, the development to low temperature applications such as a refrigeration unit has been taken. In the low temperature applications, as the suction gas pressure is very low the compression ratio is very high, and as a result the discharge gas goes to very high temperature. In order to lower discharge gas temperature, refrigerant liquid has been injected into compression pockets. Further, in case of both low temperature usage and heat pump, in order to cool down the motor refrigerant liquid bypass operating system has been adopted. We have theoretically and experimentally studied the scroll compressor behavior in case of liquid refrigerant is existed in the compession pockets. In this paper, we describe these analytical and experimental results.

Hirano, Takahisa; Hagimoto, Kiyoshi; Matsuda, Susumu

391

Dynamic Characteristics of Pressure Build Up Tank for HTS Power Cable Refrigeration System  

NASA Astrophysics Data System (ADS)

HTS power cables are cooled by the forced circulation of sub-cooled liquid nitrogen to remove heat loss and maintain a cryogenic temperature. The refrigeration systems used consist of cryocoolers, a pressure build-up tank, heat exchangers, and circulation pumps. Liquid nitrogen expands or shrinks according to the temperature variation inside the fixed volume of the refrigeration system and the cable cryostat. The system pressure also changes depending on the volume change of the liquid nitrogen. The pressure of the liquid nitrogen should be kept above a certain level to ensure its dielectric strength. In addition, the pressure should be kept below the allowable pressure level considering the mechanical strength of the refrigeration system. To enhance the pressure controllability, external heating and cooling should be possible in the pressure build-up tank. For the precise modeling of the pressure build-up tank, thermal stratification and axial thermal conduction are considered. An analysis of such a refrigeration system is performed using the commercial code 'Sinda/fluint', a comprehensive finite-difference, one-dimensional, lumped parameter tool. This paper presents the transient thermo-hydraulic characteristics and the design directions of an HTS cable refrigeration system according to a variable heat load including pressure build-up tank.

Kim, Dongmin; Park, Heecheol; Kim, Seokho; Jang, Hyunman; Kim, Yanghun

392

Cooling System Using Natural Circulation for Air Conditioning  

NASA Astrophysics Data System (ADS)

In this paper, Cooling systems with natural circulation loop of refrigerants are reviewed. The cooling system can largely reduce energy consumption of a cooling system for the telecommunication base site. The cooling system consists of two refrigeration units; vapor compression refrigeration unit and sub-cooling unit with a natural-circulation loop. The experiments and calculations were carried out to evaluate the cycle performance of natural circulation loop with HFCs and CO2. The experimental results showed that the cooling capacity of R410A is approximately 30% larger than that of R407C at the temperature difference of 20K and the cooling capacity of CO2 was approximately 4-13% larger than that of R410A under the two-phase condition. On the other hand, the cooling capacity of CO2 was approximately 11% smaller than that of R410A under the supercritical condition. The cooling capacity took a maximum value at an amount of refrigerant and lineally increased as the temperature difference increases and the slightly increased as the height difference. The air intake temperature profile in the inlet of the heat exchangers makes the reverse circulation under the supercritical state and the driving head difference for the reverse circulation depends on the density change to temperature under the supercritical state. Also, a new fan control method to convert the reverse circulation into the normal circulation was reviewed.

Okazaki, Takashi; Seshimo, Yu

393

Superinsulation in refrigerators and freezers  

SciTech Connect

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

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

1998-02-01

394

Krypton based adsorption type cryogenic refrigerator  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A. (inventor); Schember, Helene (inventor)

1987-01-01

395

Krypton based adsorption type cryogenic refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

396

EVALUATION OF REFRIGERANT FROM MOBILE AIR CONDITIONERS  

EPA Science Inventory

The report gives results of a project to provide a scientific basis for choosing a reasonable standard of purity for recycled chlorofluorocarbon (CFC) refrigerant in operating automobile air conditioners. The quality of refrigerant from air conditioners in automobiles of differen...

397

REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS  

EPA Science Inventory

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

398

Energy Saving with Absorption Refrigeration Technologies  

E-print Network

ENERGY SAVING WITH ABSORPTION REFRIGERATION TECHNOLOGIES Richard C. Davis Carrier International Corporation Syracuse, New York ABSTRACT Absorption refrigeration technology can be an economical and cost effective means of reducing energy...

Davis, R. C.

1984-01-01

399

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

E-print Network

-1 involves expansion of two-phase flow in a turbine. The Ideal VaporCompression Refrigeration Cycle The vapor-compression refrigeration is the most widely used cycle for refrigerators, air- conditioners, and heat pumps. Fig. 5-2: Schematic for ideal vapor-compression refrigeration cycle. Assumptions for ideal

Bahrami, Majid

400

Evaluating the effect of magnetocaloric properties on magnetic refrigeration performance  

NASA Astrophysics Data System (ADS)

Active magnetic regenerator (AMR) refrigerators represent an alternative to vapor compression technology that relies on the magnetocaloric effect in a solid refrigerant. Magnetocaloric materials are in development and properties are reported regularly. Recently, there has been an emphasis on developing materials with a high entropy change with magnetization while placing lower emphasis on the adiabatic temperature change. This work uses model magnetocaloric materials and a numerical AMR model to predict how the temperature change and entropy change with magnetization interact and how they affect the performance of a practical system. The distribution of the magnetocaloric effect as a function of temperature was also studied. It was found that the adiabatic temperature change in a magnetocaloric material can be more important than the isothermal entropy change for certain conditions. A material that exhibits a sharp peak in isothermal entropy change was shown to produce a significantly lower cooling power than a material with a wide peak in a practical AMR system.

Engelbrecht, K.; Bahl, C. R. H.

2010-12-01

401

An optimized rotating helium-recondensing system using Roebuck refrigerators  

NASA Astrophysics Data System (ADS)

This paper describes an optimized design of the helium-recondensing system utilizing cascade Roebuck refrigerators. A superconducting generator or motor has a superconducting field winding in its rotor that should be continuously cooled by cryogen. Liquid helium transfer from the stationary system to the rotor of the LTS (Low Temperature Superconductor) superconducting generator has been problematic, cumbersome, and inefficient. The novel concept of a rotating helium-recondensing system is contrived. The vaporized cold helium inside the rotor is isothermally compressed by centrifugal force and recondensed to 4.2 K reservoir through the expansion process. There is no helium coupling between the rotor and the stationary liquid helium storage. Thermodynamic analysis of the cascade refrigeration system is performed to determine the optimum key design parameters. The loss mechanisms are also described to point out the sources that might reduce the system performance.

Jeong, Sangkw. O. O. N.; Lee, C.

1999-09-01

402

Design of an adiabatic demagnetization refrigerator for studies in astrophysics  

NASA Technical Reports Server (NTRS)

An adiabatic demagnetization refrigerator was designed for cooling infrared bolometers for studies in astrophysics and aeronomy. The design was tailored to the requirements of a Shuttle sortie experiment. The refrigerator should be capable of maintaining three bolometers at 0.1 K with a 90% cycle. The advantage are of operations the bolometer at 0.1K. greater sensitivity, faster response time, and the ability to use larger bolometer elements without compromising the response time. The design presented is the first complete design of an ADR intended for use in space. The most important of these specifications are to survive a Shuttle launch, to operate with 1.5 K - 2.0 K space-pumped liquid helium as a heat sink, to have a 90% duty cycle, and to be highly efficient.

Castles, S.

1983-01-01

403

Analysis of Transient Behavior of a Vapor Compression Refrigeration Cycle  

NASA Astrophysics Data System (ADS)

A mathematical model for a vapor compression refrigeration cycle for automotive air conditioner is developed, which basically consists of compressor, condenser, receiver, expansion valve, evaporator, suction pressure control valve and piping. The main purpose of this model is to provide the designer with a tool for improving cooling capacity and investigating capacity control of the refrigeration cycle at transient conditions. A lumped parameter system is used for the mathematical model of the condenser and the evaporator, that is obtained with volume integral of the equation of continuity and energy over a bounded volume region. The compressor model and the piping models are also lumped parameter systems, and heat capacity of their walls are taken into account. The theoretical solutions of this model are in good agreement with the experimental results.

Fukushima, Toshihiko; Miyamoto, Seigo

404

New Regenerative Cycle for Vapor Compression Refrigeration  

SciTech Connect

The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology. Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a dynamic equilibrium method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration. The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are: (1) The application of two-step throttling of the working fluid and two-step compression of its vapor phase. (2) Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined. (3) Controlled ratio of a working fluid at the first and second step of compression. In the proposed system, the compressor compresses the vapor only to 50-60% of the final pressure, while the additional compression is provided by a jet device using internal potential energy of the working fluid flow. Therefore, the amount of mechanical energy required by a compressor is significantly reduced, resulting in the increase of efficiency (either COP or EER). The novelty of the cycle is in the equipment and in the way the multi-staging is accomplished. The anticipated result will be a new refrigeration system that requires less energy to accomplish a cooling task. The application of this technology will be for more efficient designs of: (1) Industrial chillers, (2) Refrigeration plants, (3) Heat pumps, (4) Gas Liquefaction plants, (5) Cryogenic systems.

Mark J. Bergander

2005-08-29

405

Acoustic impedance measurements of pulse tube refrigerators  

NASA Astrophysics Data System (ADS)

Complex acoustic impedance is determined in a prototype refrigerator that can mimic orifice-type, inertance-type, and double inlet-type pulse tube refrigerators from simultaneous measurements of pressure and velocity oscillations at the cold end. The impedance measurements revealed the means by which the oscillatory flow condition in the basic pulse tube refrigerator is improved by additional components such as a valve and a tank. The working mechanism of pulse tube refrigerators is explained based on an electrical circuit analogy.

Iwase, Takashi; Biwa, Tetsushi; Yazaki, Taichi

2010-02-01

406

Refrigeration of separate, user-supplied payloads with Normal-Insulator-Superconductor tunnel junctions  

NASA Astrophysics Data System (ADS)

Normal metal-Insulator-Superconductor (NIS) tunnel junctions can be used to selectively remove the hottest electrons in the normal metal, thereby causing it to cool. NIS tunnel junctions have already been used to cool lithographically integrated payloads [1], but this requires integration of two disparate fabrication processes. To increase the flexibility of NIS refrigerators, we have designed a stage cooler based on NIS tunnel junctions that will be able to cool arbitrary, user-supplied payloads from 300 mK to 100 mK. This stage cooler can be backed by a helium-3 refrigerator to provide a lightweight and simple means of reaching 100 mK in space applications. In this paper, we describe the design of our stage cooler and present calculations of the cooling power and time required to reach 100 mK.

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

2012-04-01

407

Influence of other rare earth ions on the optical refrigeration efficiency in Yb:YLF crystals.  

PubMed

We investigated the effect of rare earth impurities on the cooling efficiency of Yb³?:LiYF? (Yb:YLF). The refrigeration performance of two single crystals, doped with 5%-at. Yb and with identical history but with different amount of contaminations, have been compared by measuring the cooling efficiency curves. Spectroscopic and elemental analyses of the samples have been carried out to identify the contaminants, to quantify their concentrations and to understand their effect on the cooling efficiencies. A model of energy transfer processes between Yb and other rare earth ions is suggested, identifying Erbium and Holmium as elements that produce a detrimental effect on the cooling performance. PMID:25402099

Di Lieto, Alberto; Sottile, Alberto; Volpi, Azzurra; Zhang, Zhonghan; Seletskiy, Denis V; Tonelli, Mauro

2014-11-17

408

Ternary Dy-Er-Al magnetic refrigerants  

DOEpatents

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

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

1995-07-25

409

Ternary Dy-Er-Al magnetic refrigerants  

DOEpatents

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

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

1995-07-25

410

Solar Refrigerators Store Life-Saving Vaccines  

NASA Technical Reports Server (NTRS)

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

2014-01-01

411

Method and apparatus for desuperheating refrigerant  

DOEpatents

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

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

1997-01-01

412

Conversion of centrifugal chillers to alternate refrigerants  

Microsoft Academic Search

The discovery of the adverse effect of certain chloroflourocarbon refrigerants on the upper atmosphere brought about the need to eliminate the offending refrigerants and replace them with those that are environmentally friendly. The use of a refrigerant different from that used in the original design of a centrifugal chiller creates issues of capacity, efficiency and reliability. The scope of the

G. E. Roark

1995-01-01

413

World trade of refrigerators and freezers  

Microsoft Academic Search

This market research provides an overview of the world trade of refrigerators and freezers, with data at world-wide level and data on the evolution of appliances trade in 60 countries (selected according to their contribution to international trade of refrigerators and freezers). Data on production and consumption in quantity are included for each of the 60 countries.The growth of refrigerators

Aurelio Volpe; Stefania Pelizzari; Donatella Cheri

2007-01-01

414

On optimum interstage pressure for two-stage and mechanical-subcooling vapor-compression refrigeration cycles  

SciTech Connect

The objective of the present study is to demonstrate that the optimum interstage pressure for a two-stage refrigeration system can be approximated by the saturation pressure corresponding to the arithmetic mean of the condensing and evaporating temperatures. It is also shown that the optimum performance of a refrigeration system with mechanical sub-cooling occurred when the subcooler compressor (saturation suction) temperature corresponds to the arithmetic mean of the condensing and evaporating temperatures.

Zubair, S.M.; Khan, S.H. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Mechanical Engineering

1995-02-01

415

Experimental studies of a steam jet refrigeration cycle: Effect of the primary nozzle geometries to system performance  

Microsoft Academic Search

This paper describes an experimental investigation of a steam jet refrigeration. A 1kW cooling capacity experimental refrigerator was constructed and tested. The system was tested with various operating temperatures and various primary nozzles. The boiler saturation temperature ranked from 110 to 150°C. The evaporator temperature was fixed at 7.5°C. Eight primary nozzles with difference geometries were used. Six nozzles have

Natthawut Ruangtrakoon; Satha Aphornratana; Thanarath Sriveerakul

2011-01-01

416

Operation of the Tevatron Satellite Refrigerators for 0.75- and 2.0- Kilometer-Long Magnet Strings  

Microsoft Academic Search

The Tevatron magnets at Fermilab are cooled by a hybrid system which consists of a 5000 liters\\/hr central helium liquefier coupled with a small-diameter liquid transfer line connecting twenty-four satellite refrigerators. The transfer line supplies liquid helium for both the refrigerators and the magnet lead flow as well as liquid nitrogen for the magnet shields. The satellites act as amplifiers

C. H. Rode; R. A. Andrews; R. Ferry; J. Gannon; J. Makara; M. Martin; J. Misek; D. Mizicko; T. Peterson; J. Theilacker

1983-01-01

417

Adsorption refrigeration—An efficient way to make good use of waste heat and solar energy  

Microsoft Academic Search

This paper presents the achievements gained in solid sorption refrigeration prototypes since the end of the l970s, when interest in sorption systems was renewed. The applications included are ice making and air conditioning. The latter includes not only cooling and heating, but also dehumidification by desiccant systems. The prototypes presented were designed to use waste heat or solar energy as

R. Z. Wang; R. G. Oliveira

2006-01-01

418

A Reversible Thermally Driven Pump for Use in a Sub-Kelvin Magnetic Refrigerator  

NASA Technical Reports Server (NTRS)

A document describes a continuous magnetic refrigerator that is suited for cooling astrophysics detectors. This refrigerator has the potential to provide efficient, continuous cooling to temperatures below 50 mK for detectors, and has the benefits over existing magnetic coolers of reduced mass because of faster cycle times, the ability to pump the cooled fluid to remote cooling locations away from the magnetic field created by the superconducting magnet, elimination of the added complexity and mass of heat switches, and elimination of the need for a thermal bus and single crystal paramagnetic materials due to the good thermal contact between the fluid and the paramagnetic material. A reliable, thermodynamically efficient pump that will work at 1.8 K was needed to enable development of the new magnetic refrigerator. The pump consists of two canisters packed with pieces of gadolinium gallium garnet (GGG). The canisters are connected by a superleak (a porous piece of VYCOR glass). A superconducting magnetic coil surrounds each of the canisters. The configuration enables driving of cyclic thermodynamic cycles (such as the sub-Kelvin Active Magnetic Regenerative Refrigerator) without using pistons or moving parts.

Miller, Franklin K.

2012-01-01

419

Active nocturnal space cooling system  

SciTech Connect

A nocturnal evaporative cooling system appropriate for retrofitting to an active solar heated house was designed and installed at the Sonoma State University Solar/Energy Center. The system was operated during the summer and early fall of 1980, and tests were conducted to evaluate its performance. Two simple variations in the system design were compared: an indirect evaporative cooling configuration and a direct evaporative cooling configuration. The first used an evaporative air cooler, a heat exchanger and a pump to remove heat from water in a storage tank; the second used a fan blowing across the surface of the water in the storage tank to evaporatively cool the water. Test results suggested that the direct evaporative cooling configuration operated at a higher coefficient of performance (COP) at relatively high operating temperature differentials and that the indirect configuration operated at a higher COP at relatively low operating temperature differentials. A computer simulation indicated that the nocturnal evaporative cooling system in the indirect cooling configuration offered good potential for use in the hot central valleys of California. An economic analysis compared the cooling system in the indirect configuration to a refrigeration air conditioner of similar capacity. Rate structure implications as well as life cycle costs were examined. Calculations based on current electric rates showed that the nocturnal cooling system, slightly modified from the prototype design, was less costly.

Livingston, J.; Ablett, K.; Cinciarelli, K.; Dennis, A.; Leker, B.; Livingston, P.; McBride, T.; Treppa, D.; Norwick, S.A.

1981-04-30

420

Cooling devices and methods for use with electric submersible pumps  

DOEpatents

Cooling devices for use with electric submersible pump motors include a refrigerator attached to the end of the electric submersible pump motor with the evaporator heat exchanger accepting all or a portion of the heat load from the motor. The cooling device can be a self-contained bolt-on unit, so that minimal design changes to existing motors are required.

Jankowski, Todd A; Hill, Dallas D

2014-12-02

421

78 FR 53374 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Procedures for Refrigerators, Refrigerator-Freezers, and Freezers AGENCY...procedures for refrigerators, refrigerator-freezers, and freezers in the Federal...procedures for refrigerators, refrigerator-freezers, and freezers and...

2013-08-29

422

Technical Trend of Refrigeration System using Natural Working Fluids  

NASA Astrophysics Data System (ADS)

Technical trend of refrigeration system using natural refrigerants (or natural working fluids) was generally overviewed mainly by the proceedings of the International Conference of Natural Working Fluids past these few years. Hydrocarbon, carbon dioxide, water and air are mainly used as new refrigerants. Risk assessment of these flammable refrigerants was widely discussed. Hydrocarbon has been already widely used for refrigerators in Germany. Carbon-dioxide is now focused as a new refrigerant for air-conditioners of automobiles and water heaters. Turbo chiller with water as refrigerant has been tested in Germany. Air cycle refrigeration systems were applied to commercial freezer and for transportation. Natural refrigerants are also paid attention as secondary refrigerants.

Hara, Toshitsugu

423

Solar-Powered Refrigeration System  

NASA Astrophysics Data System (ADS)

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

Ewert, Michael K.; Bergeron, David J., III

2002-10-01

424

Performance modeling of optical refrigerators  

Microsoft Academic Search

Optical refrigeration using anti-Stokes fluorescence in solids has several advantages over more conventional techniques including low mass, low volume, low cost and no vibration. It also has the potential of allowing miniature cryocoolers on the scale of a few cubic centimeters. It has been the topic of analysis and experimental work by several organizations. In 2003, we demonstrated the first

Gary Mills; Allan Mord

2006-01-01

425

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

426

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

427

Model Based Control Refrigeration Systems  

E-print Network

Model Based Control of Refrigeration Systems Ph.D. Thesis Lars Finn Sloth Larsen Central R & D Sloth Larsen Printing: Budolfi tryk Aps #12;To my wife Helena #12;#12;Preface and Acknowledgments and Innovation and Danfoss A/S. November 2005, Nordborg, Denmark Lars Finn Sloth Larsen v #12;#12;Summary

428

Low-temperature magnetic refrigerator  

DOEpatents

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

Barclay, John A. (Los Alamos, NM)

1985-01-01

429

Alternative refrigerants R123a, R134, R141b, R142b, and R152a: Critical temperature, refractive index, surface tension, and estimates of liquid, vapor, and critical densities  

SciTech Connect

Differential capillary rise and refractive index data are reported for five alternative refrigerants: R123a (CHClF-CClF{sub 2}), R134 (CHF{sub 2}-CHF{sub 2}), R141b (CCl{sub 2}F-CH{sub 3}), R142b (CClF{sub 2}-CH{sub 3}), and R152a (CHF{sub 2}-CH{sub 3}). The data extend from about 25{degree}C to the critical point of each fluid and directly yield the critical temperature {Tc} and the temperature-dependent capillary length. The present data were combined with liquid density data (near ambient temperature) to determine the Lorentz-Lorenz constant. The Lorentz-Lorenz relation is used to estimate the liquid, vapor, and critical densities, and the surface tension. The surface tension {sigma} of seven substituted ethane refrigerants (the present five and R123 (CHCl{sub 2}-CF{sub 3}) and R134a (CF{sub 3}-CH{sub 2}F)) is within {plus minus}10% of the expression: {sigma} = 64 mN/m{center dot}t{sup 1.26}, where t = ({Tc} {minus} T)/{Tc} is the reduced temperature measured from the critical temperature. The surface tension of the same seven refrigerants is within {plus minus}5% of the expression {sigma} = 5.7t{sup 1.26}k{sub B}{Tc}(N{sub A}/V{sub c}){sup 2/3}, where k{sub B}, N{sub A}, and V{sub c} are the Boltzmann constant, the Avogadro constant, and the molar critical volume, respectively.

Chae, Hee Baik; Schmidt, J.W.; Moldover, M.R. (National Institute of Standards and Technology, Gaithersburg, MD (USA))

1990-12-13

430

Demonstration of High Efficiency Elastocaloric Cooling with Large Delta T Using NiTi Wires  

Microsoft Academic Search

Vapor compression (VC) is by far the most dominant technology for meeting all cooling and refrigeration needs around the world. It is a mature technology with the efficiency of modern compressors approaching the theoretical limit, but its envi-ronmental footprint remains a global problem. VC refrigerants such as hydrochlo-roflurocarbons (HCFCs) and hydrofluorocarbons (HFCs) are a significant source of green house gas

Jun Cui; Yiming Wu; Jan Muehlbauer; Yunho Hwang; Reinhard Radermacher; Sean Fackler; Manfred Wuttig; Ichiro Takeuchi

2012-01-01

431

Experimental analysis of a transfer function for an air cooled evaporator  

Microsoft Academic Search

A transfer function to model a direct expansion air cooled evaporator, inserted in a vapor compression refrigeration plant, is deduced by means of experimental analysis. For inlet air temperatures onto the evaporator and refrigerant mass flow rate variable in appropriate ranges, the evaporator dynamic behavior is simulated by a linear model with delay. The results of transfer function are compared

C. Aprea; C. Renno

2001-01-01

432

A combined power and cooling cycle modified to improve resource utilization efficiency using a distillation stage  

Microsoft Academic Search

A combined power and cooling cycle is being investigated. The cycle is a combination of a Rankine cycle and an absorption refrigeration cycle. The vapor exiting the turbine in this cycle is cold enough to extract refrigeration output. This combined cycle is being proposed for application with lower temperature heat sources such as solar, geothermal, and industrial waste heat with

S. Vijayaraghavan; D. Y. Goswami

2006-01-01

433

Demand Side Management (DSM) Through Absorption Refrigeration Systems  

E-print Network

to generate required refrigeration, is also an ideal solution to both reducing the industrial waste heat and to replace the CFC refrigerant operated mechanical driven refrigeration system. The concept of using waste heat for absorption refrigeration... refrigeration potential will be illustrated by two recent case studies. INTRODUCTION This paper deals with a Demand Side Management (DSM) option of using waste heat for refrigeration. Absorption Refrigeration from waste heat offers a viable option for DSM...

Chao, P. Y.; Shukla, D.; Amarnath, A.; Mergens, E.

434

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

SciTech Connect

The impending phaseout of CFCs and HCFCs has led to a worldwide search for refrigerants that can provide equivalent performance while not damaging the environment. Long used as a working fluid in industrial and large-scale refrigeration, 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 applications. Utilization of ammonia in applications where its safety considerations and technical concerns can be addressed provides the best growth opportunity for adoption as a replacement refrigerant. Applications such as district or large-scale cooling, thermal storage, packaged systems, and combined systems hold promise for increased usage of ammonia. Ongoing research and development are providing solutions to technical considerations, and innovations in safety and containment of ammonia are addressing those particular concerns, but code restrictions and regulations present the greatest barrier to wider adoption of ammonia as an alternate refrigerant in the US To encourage wider use, future efforts will need to continue on improved safety and more efficient design, along with an increased emphasis on educating and informing industry and the public about the advantages ammonia and the factors restricting its use.

Fairchild, P.D.; Baxter, V.D.

1995-12-31

435

End-Use Load and Consumer Assessment Program: Analysis of residential refrigerator/freezer performance  

SciTech Connect

The Bonneville Power Administration (Bonneville) is conducting a large end-use data acquisition program in an effort to understand how energy is utilized in buildings with permanent electric space heating equipment in the Pacific Northwest. The initial portion of effort, known as the End-Use Load and Consumer Assessment Program (ELCAP), was conducted for Bonneville by the Pacific Northwest Laboratory (PNL). The collection of detailed end-use data provided an opportunity to analyze the amount of energy consumed by both refrigerators and separate freezers units located in residential buildings. By obtaining this information, the uncertainty of long- term regional end-use forecasting can be improved and potential utility marketing programs for new appliances with a reduced overall energy demand can be identified. It was found that standby loads derived from hourly averages between 4 a.m. and 5 a.m. reflected the minimum consumption needed to maintain interior refrigerator temperatures at a steady-state condition. Next, an average 24-hour consumption that included cooling loads from door openings and cooling food items was also determined. Later, analyses were conducted to develop a model capable of predicting refrigerator standby loads and 24-hour consumption for comparison with national refrigerator label ratings. Data for 140 residential sites with a refrigeration end-use were screened to develop a sample of 119 residences with pure refrigeration for use in this analysis. To identify those refrigerators that were considered to be pure (having no other devices present on the circuit) in terms of their end-use classification, the screening procedure used a statistical clustering technique that was based on standby loads with 24-hour consumption. 5 refs., 18 figs., 4 tabs.

Ross, B.A.

1991-09-01

436

Forced two-phase cooling of the TPC superconducting solenoid  

NASA Astrophysics Data System (ADS)

The cryogenic tests of the TPC 2-meter diameter superconducting solenoid on a 200 W refrigerator with gas-bearing turbines is described. The solenoid is cooled with two phase helium in forced flow around the superconducting winding. The two-phase helium was circulated using either the J-T circuit flow or a bellows type liquid helium pump. The particular problems associated with running a variable load on a gas-bearing turbine refrigerator are discussed.

Green, M. A.; Barrera, F.; Petersen, H.; Rago, C. E.; Rinta, R. I.; Talaska, D.; Taylor, J. D.; Vanslyke, H.; Watt, R. D.

1983-08-01

437

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

438

Dehumidifying Air for Cooling & Refrigeration: Nanotechnology Membrane-based Dehumidifier  

SciTech Connect

Broad Funding Opportunity Announcement Project: Dais is developing a product called NanoAir which dehumidifies the air entering a building to make air conditioning more energy efficient. The system uses a polymer membrane that allows moisture but not air to pass through it. A vacuum behind the membrane pulls water vapor from the air, and a second set of membranes releases the water vapor outside. The membrane’s high selectivity translates into reduced energy consumption for dehumidification. Dais’ design goals for NanoAir are the use of proprietary materials and processes and industry-standard installation techniques. NanoAir is also complementary to many other energy saving strategies, including energy recovery.

None

2010-10-01

439

Cooling Enhancement Using Inhomogeneous Thermoelectric Materials Zhixi Bian and Ali Shakouri  

E-print Network

Cooling Enhancement Using Inhomogeneous Thermoelectric Materials Zhixi Bian and Ali Shakouri Baskin The maximum cooling temperature of a thermoelectric refrigerator made of uniform bulk material is limited for a thermoelectric cooler based on single crystal silicon. Maximum Cooling of Thermoelectric Materials It is well

440

Evaluation of nonazeotropic refrigerant mixtures for capacity modulation  

SciTech Connect

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

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

1988-01-01

441

Improved Design of the Intermediate Stage of a Dry Dilution Refrigerator  

NASA Astrophysics Data System (ADS)

Cryogen free dilution refrigerators (DR) have become very popular with scientists working at sub-Kelvin temperatures. Ease of operation, reliability and cost effectiveness are first-rate with these refrigerators. In our original cryostat, and in almost all commercial models available, the 3He flow is cooled in three major components to its lowest temperature of about 10 mK, with the first cooling stage being a two-stage pulse tube cryocooler, the second stage an intermediate stage and the third stage a dilution refrigeration unit. The intermediate stage is made from a flow restriction and a heat exchanger which makes use of the cold 3He gas pumped from the still to cool the back-streaming 3He; it is similar to a Joule-Thomson stage. Although the intermediate cooling stage can be left out altogether, it is desirable when a high cooling power of the still is required to heat sink a radiation shield and coaxial and other electric cables. In our paper we present a redesigned heat exchanger of the intermediate stage which was made mostly from copper screens; construction details and performance data of the heat exchanger are described. The heat exchanger is shorter than its predecessors, allowing for a more compact construction of the cryostat.

Uhlig, K.

2010-04-01

442

Proposed designs for a “dry” dilution refrigerator with a 1 K condenser  

NASA Astrophysics Data System (ADS)

Recent development of "dry" dilution refrigerators has used mechanical cryocoolers and Joule-Thomson expansion stages to cool and liquefy the circulating 3He. While this approach has been highly successful, we propose three alternative designs that use independently-cooled condensers. In the first, the circulating helium is precooled by a mechanical cooler, and liquified by self-contained 4He sorption coolers. In the second, the helium is liquefied by a closed-cycle, continuous flow 4He refrigerator operating from a room temperature pump. Finally, the third scheme uses a separate 4He Joule-Thomson stage to cool the 3He condenser. The condensers in all these schemes are analogous to the "1-K pot" in a conventional dilution refrigerator. Such an approach would be advantageous in certain applications, such as instrumentation for astronomy and particle physics experiment, where a thermal stage at approximately 1 K would allow an alternative heat sink to the still for electronics and radiation shielding, or quantum computer research where a large number of coaxial cables must be heat sunk in the cryostat. Furthermore, the behaviour of such a refrigerator is simplified due to the separation of the condenser stage from the dilution circuit, removing the complex interaction between the 4-K, Joule-Thomson, still and mixing chamber stages found in current dry DR designs.

Hollister, Matthew I.; Woodcraft, Adam L.

2009-07-01

443

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

ERIC Educational Resources Information Center

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

Carey, John

444

Control method for mixed refrigerant based natural gas liquefier  

Microsoft Academic Search

In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by

Kenneth J. Kountz; Patrick M. Bishop

2003-01-01

445

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

446

Suction muffler for refrigeration compressor  

DOEpatents

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

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

1983-01-01

447

Suction muffler for refrigeration compressor  

DOEpatents

A hermetic refrigeration compressor includes a suction muffler formed from two pieces of plastic material mounted on the cylinder housing. One piece is cylindrical in shape with an end wall having an aperture for receiving a suction tube connected to the cylinder head. The other piece fits over and covers the other end of the cylindrical piece, and includes a flaring entrance horn which extends toward the return line on the sidewall of the compressor shell. 5 figs.

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

1983-01-25

448

Theoretical Analysis of Heat Pump Cycle Characteristics with Pure Refrigerants and Binary Refrigerant Mixtures  

NASA Astrophysics Data System (ADS)

In recent years there has been an increasing interest of the use of nonazeotropic binary mixtures to improve performance in heat pump systems, and to restrict the consumption of chlorofluorocarbon (CFC) refrigerants as internationally agreed-upon in the Montreal Protocol. However, the available knowledge on the thermophysical properties of mixtures is very much limited particularly with respect to quantitative information. In order to systematize cycle performance with Refrigerant 12 (CCl2F2) + Refrigerant 22 (CHClF2) and Refrigerant 22 + Refrigerant 114 (CClF2-CClF2) systems which are technically important halogenated refrigerant mixtures, the heat pump cycle analysis in case of using these mixtures was theoretically studied. It became clear that the maximum coefficients of performance with various pure refrigerants and binary refrigerant mixtures were obtained at the reduced condensing temperature being 0.9 when the same temperature difference between condensing and evaporating temperature was chosen.

Kagawa, Noboru; Uematsu, Masahiko; Watanabe, Koichi

449

Multicomponent gas sorption Joule-Thomson refrigeration  

NASA Technical Reports Server (NTRS)

The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

Jones, Jack A. (inventor); Petrick, S. Walter (inventor); Bard, Steven (inventor)

1991-01-01

450

Ammonia as a refrigerant of choice  

SciTech Connect

This paper reports that the greatest potential for a swing to the use of ammonia would be in the following areas: Large, central facility-type air- conditioning applications. Central district heating and cooling systems, with isolated engine room facilities, represent a natural for the advantages of ammonia screw compressor water or glycol chilling over the R-11 replacement systems. Latent heat storage systems. Here, the long history of ammonia systems (primarily in the dairy industry) will bring ammonia back into the picture. This applies to both ice-builder and ice accumulator systems. A large system of this type is being built for an industrial air-conditioning application in the Midwest and should be available shortly for case history write-ups. Packaged water chilling systems in the 30-200 ton capacity range. At least two manufacturers or assemblers are considering offering standard units in this area. The advent and widely increasing use of screw compressors has added to the potential for ammonia applications. (Ammonia was the predominant refrigerant for the first screw compressors.) Use of screw compressors instead of centrifugals is predicted to increase.

Miner, S.M.

1990-12-01

451

Influence of Refrigerant Oil on Evaporator Performance  

NASA Astrophysics Data System (ADS)

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

Kim, Jong Soo; Katsuta, Masafumi

452

Solid-vapor adsorption refrigeration system development  

NASA Astrophysics Data System (ADS)

The study describes the development of heat-activated industrial refrigeration systems using ammoniated complex compound sorption media. The focus was on single-stage cycles for low temperature (+20 F and below) refrigeration. Compared to vapor compression refrigeration, these cycles have the advantages of lower operating energy costs, reduction of peak electrical demand and associated demand charges, and reduced maintenance costs due to replacement of the compressor with solid-state sorbers. In many cases, particularly for refrigeration at -40 F and below, complex compound sorption cycles also have the potential for lower first cost than conventional electrically driven refrigeration systems. Technical issues addressed included the following: economic optimization of sorber design, demonstration of cyclic stability of the sorption reactions, construction material compatibility, and reactor scale-up. Sorption reactions for refrigeration at -40 and -70 F were demonstrated. Optimum heat exchanger configuration, complex compound loading, and cycle time were determined.

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

1991-12-01

453

Compatibility of refrigerants and lubricants with elastomers  

SciTech Connect

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

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

1992-07-01

454

Stochastic Cooling  

SciTech Connect

Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

Blaskiewicz, M.

2011-01-01

455

Experimental investigation on ejecting low-temperature cooling superconducting magnets  

NASA Astrophysics Data System (ADS)

With the development of the high-temperature superconducting (HTS) materials and refrigeration technologies, using ejecting refrigeration to cool the superconducting materials becomes the direction of HTS applications. In this paper, an experimental study has been carried out on the basis of the theory of analyzing the ejecting low-temperature cooling superconducting magnet. The relationship between area ratios and refrigeration performance at different system pressures was derived. In addition, the working fluid flow and suction chamber pressure of the ejector with different area ratios at various inlet pressures have been examined to obtain the performance of ejectors under different working conditions. The result shows that the temperature of liquid nitrogen can be reduced to 70 K by controlling the inlet water pressure when the pressurized water at 20 °C is used to eject the saturated liquid nitrogen, which can provide the stable operational conditions for the HTS magnets cooling.

Liu, Bin; Zhang, Qiang; Tong, Ming-wei; Hu, Peng; Wu, Shuang-ying; Cai, Qin; Qin, Zeng-hu

2013-10-01

456

Thermodynamic properties for the alternative refrigerants  

Microsoft Academic Search

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

Mark O McLinden; Eric W Lemmon; Richard T Jacobsen

1998-01-01

457

Manganese Nitride Sorption Joule-Thomson Refrigerator  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.; Phillips, Wayne M.

1992-01-01

458

Performance of Screw Compressor for Small-Capacity Helium Refrigerators  

NASA Astrophysics Data System (ADS)

A helium compressor is one of the important components comprising a cryogenic refrigerator. The purpous of this investigation is to develop a new small-capacity helium screw compressor. The performance of a single-stage compressor at high compression ratio and the cooling performance of the compressor are investigated. A semi-hermetic screw compressor with new profile screw rotors, with which high performance can be obtained, is utilized in this investigation. Lubricating oil is applied to cool the compressor motor and the compressed gas. As a result, an overall isentropic efficiency of 80% is obtained when helium is compressed to a compression ratio of 19.8 with a single-stage screw compressor. At the same time, the temperature of a compressor motor and discharge gas can be maintained at low levels. Therefore, it is found that a single-stage screw compressor can compress helium to high compression ratio.

Urashin, Masayuki; Matsubara, Katsumi; Izunaga, Yasushi

459

Cryogen-free dilution refrigerator for ACTPOL polarization- sensitive receiver  

NASA Astrophysics Data System (ADS)

We present a new cryogenic receiver for the Atacama Cosmology Telescope (ACT), a six-meter diameter off-axis Gregorian telescope located at an altitude of 5,200 meters (17,000 ft.) on Cerro Toco, in Northern Chile. The focal plane contains 3000 polarization-sensitive transition edge sensor (TES) bolometers, and is cooled to below 100 mK with a removable pulse-tube based customised JDry-100 dilution refrigerator insert. The optical tubes and the rest of the receiver are cooled with a dedicated pulse tube to below 3 K. Details of the receiver- to-telescope integration and first season on-site operation are described, including detector base temperature stability in vertical and tilted position as well as remote operation via Ethernet link.

Shvarts, V.; Zhao, Z.; Devlin, M. J.; Klein, J.; Lungu, M.; Schmitt, B.; Thornton, R.

2014-12-01

460

Progress in the Development of a Continuous Adiabatic Demagnetization Refrigerator  

NASA Technical Reports Server (NTRS)

We report on recent progress in the development of a continuous adiabatic demagnetization refrigerator (CADR). Continuous operation avoids the constraints of long hold times and short recycle times that lead to the generally large mass of single-shot ADRs, allowing us to achieve an order of magnitude larger cooling power per unit mass. Our current design goal is 10 micro W of cooling at 50 mK using a 6-10 K heat sink. The estimated mass is less than 10 kg, including magnetic shielding of each stage. The relatively high heat rejection capability allows it to operate with a mechanical cryocooler as part of a cryogen-free, low temperature cooling system. This has the advantages of long mission life and reduced complexity and cost. We have assembled a three-stage CADR and have demonstrated continuous cooling using a superfluid helium bath as the heat sink. The temperature stability is 8 micro K rms or better over the entire cycle, and the cooling power is 2.5 micro W at 60 mK rising to 10 micro W at 100 mK.

Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Jackson, Michael; King, Todd; Tuttle, James; Krebs, Carolyn A. (Technical Monitor)

2002-01-01

461

Consideration of sub-cooled LN2 circulation system for HTS power machines  

NASA Astrophysics Data System (ADS)

We consider a sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The planned circulation system consists of a sub-cool heat exchanger (subcooler) and a circulation pump. The sub-cooler will be connected to a neon turbo- Brayton cycle refrigerator with a cooling power of 2 kW at 65 K. Sub-cooled LN will be delivered into the sub-cooler by the pump and cooled within it. Sub-cooled LN is adequate fluid for cooling HTS power equipment, because its dielectric strength is high and it supports a large critical current. However, a possibility of LN solidification in the sub-cooler is a considerable issue. The refrigerator will produce cold neon gas of about 60 K, which is lower than the nitrogen freezing temperature of 63 K. Therefore, we designed two-stage heat exchangers which are based on a plate-fin type and a tube-intube type. Process simulations of those heat exchangers indicate that sub-cooled LN is not frozen in either sub-cooler. The plate-fin type sub-cooler is consequently adopted for its reliability and compactness. Furthermore, we found that a cooling system with a Brayton refrigerator has the same total cooling efficiency as a cooling system with a Stirling refrigerator.

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

2012-06-01

462

Conceptual design of a 0.1 W magnetic refrigerator for operation between 10 K and 2 K  

NASA Astrophysics Data System (ADS)

The design of a magnetic refrigerator for space applications is discussed. The refrigerator is to operate in the temperature range of 10 K-2 K, at a 2 K cooling power of 0.10 W. As in other magnetic refrigerators operating in this temperature range GGG has been selected as the refrigerant. Crucial to the design of the magnetic refrigerator are the heat switches at both the hot and cold ends of the GGG pill. The 2 K heat switch utilizes a narrow He II filled gap. The 10 K heat switch is based on a narrow helium gas gap. For each switch, the helium in the gap is cycled by means of activated carbon pumps. The design concentrates on reducing the switching times of the pumps and the switches as a whole. A single stage system (one magnet; one refrigerant pill) is being developed. Continuous cooling requires the fully stationary system to have at least two stages running parallel/out of phase with each other. In order to conserve energy, it is intended to recycle the magnetic energy between the magnets. To this purpose, converter networks designed for superconducting magnetic energy storage are being studied.

Helvensteijn, Ben P. M.; Kashani, Ali

463

Experimental investigation of two-stage active magnetic regenerative refrigerator operating between 77 K and 20 K  

NASA Astrophysics Data System (ADS)

This paper presents an experimental investigation on a magnetic refrigerator operating between 77 K and 20 K. Since the magneto-caloric effect of typical magnetic refrigerant is concentrated in a narrow temperature region, four different rare-earth intermetallic compounds (GdNi2, Dy0.85Er0.15Al2, Dy0.5Dr0.5Al2, and Gd0.1Dy0.9Ni2) are utilized according to their favorable temperature regions. The magnetic refrigerator is composed of two stages each of that is made of two different porous active magnetic regenerators. Helium gas as the heat transfer medium in the magnetic refrigerator is shuttled similar to a GM type pulse tube refrigerator so that the overall cooling capacity is enhanced by gas expansion effect when both gas and magnetic expansions are properly coordinated. The approximate peak magnetic field of 4 T is provided for the internal region of the regenerators by the AC superconducting magnet which can fast ramp up to the maximum field for 3 s. The fabricated magnetic refrigerator reached the lowest no-load temperature of 24 K and the whole temperature span was approximately 56 K rather than 57 K. The cooling performance of the system is sensitive according to the load match between the first and the second stages in conjunction with helium mass flow rate distribution.

Kim, Youngkwon; Park, Inmyong; Jeong, Sangkwon

2013-10-01

464

Development of a novel refrigeration system for refrigerated trucks incorporating phase change material  

Microsoft Academic Search

An innovative refrigeration system incorporating phase change material (PCM) is proposed to maintain refrigerated trucks at the desired thermal conditions. The advantage of using PCM to maintain low temperatures is that a conventional refrigeration system does not have to be located on-board the vehicle. In addition, the system consumes less energy and produces much lower local greenhouse gas (GHG) emissions.

Ming Liu; Wasim Saman; Frank Bruno

2012-01-01

465

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

E-print Network

efficiency Recommended applications Screw and piston compressor based heat pumps #12;GEA Refrigeration ammonia Type of use chiller & heat pump Compressor Expansion valve Refrigerant Evaporator Condenser Qe Motor Qoc Oil-cooler (screws) Desuperheater Qd #12;GEA Refrigeration Technologies10 Achema 2012

Oak Ridge National Laboratory

466

Evaluation of a two-evaporator refrigerator-freezer using nonazeotropic refrigerant mixtures. Final report  

SciTech Connect

The temperature of a nonazeotropic mixture of refrigerants changes during evaporation and condensation at constant pressure. Refrigerant mixtures offer the potential of better matching the two temperature levels (approximately 38/sup 0/F in the fresh food compartment and 5/sup 0/F in the freezer) in a household refrigerator-freezer than a single refrigerant. This feature may reduce energy consumption. The objective of this project was to investigate, through laboratory testing, the feasibility of using refrigerant mixtures to save energy. The unit selected for testing was the Amana ESTR-18D, two evaporator refrigerator-freezer developed jointly under US Department of Energy sponsorship by Arthur D. Little, Inc., and Amana Refrigeration, Inc. Tests using two mixture concentrations of R22 and R114 refrigerants demonstrated reliable refrigerator performance but no appreciable energy savings. An analytical model was developed to identify modifications to the refrigeration system in order to realize the benefits of mixed refrigerants. Based on the model, the expansion device was modified to reduce the system pressure ratio. Predicted benefits in evaporator heat exchanger effectiveness were observed, but were offset by the reduced heat capacity and density of the mixtures compared to the standard refrigerant. No energy savings were demonstrated with the ESTR-18D test unit. 9 references, 6 figures, 9 tables.

Not Available

1984-09-01

467

Safety considerations in the design of Spacelab refrigerator/freezer  

NASA Astrophysics Data System (ADS)

A vapor compression refrigerator/freezer has been designed for Spacelab to conduct life sciences experiments. It is equipped with different safety features to eliminate all probable types of failures. The whole Freon loop is enclosed in a second containment so that any leakage of Freon can be contained. The unit is provided with an 'Emergency On' switch to actuate during backup mode which provides the spacecraft power directly to the compressor and the cooling fans while removing the power supply and all normal control elements from the circuit. During this mode, the compressor runs continuously when operating as a freezer (-22 C) and is controlled by a thermostat to cycle when operating as a refrigerator (4 C). It has a push button switch at the front panel to momentarily power the thermometer by a battery to monitor the inside temperature during an emergency. It has a door switch which shuts off the internal cooling fans when the door is opened. All the important critical performance data will be downlinked through a data connector to monitor during mission.

Hye, A.

1985-07-01

468

Safety considerations in the design of Spacelab refrigerator/freezer  

NASA Technical Reports Server (NTRS)

A vapor compression refrigerator/freezer has been designed for Spacelab to conduct life sciences experiments. It is equipped with different safety features to eliminate all probable types of failures. The whole Freon loop is enclosed in a second containment so that any leakage of Freon can be contained. The unit is provided with an 'Emergency On' switch to actuate during backup mode which provides the spacecraft power directly to the compressor and the cooling fans while removing the power supply and all normal control elements from the circuit. During this mode, the compressor runs continuously when operating as a freezer (-22 C) and is controlled by a thermostat to cycle when operating as a refrigerator (4 C). It has a push button switch at the front panel to momentarily power the thermometer by a battery to monitor the inside temperature during an emergency. It has a door switch which shuts off the internal cooling fans when the door is opened. All the important critical performance data will be downlinked through a data connector to monitor during mission.

Hye, A.

1985-01-01

469

Effects of regenerator geometry on pulse tube refrigerator performance.  

PubMed

This paper gives results of the cooling performance of a double-inlet pulse tube refrigerator using various regenerators. The same pulse tube was used for all the experiments and measured 4.76 mm in diameter and 46.2 mm in length. A commercial linear compressor with a swept volume of 4 cm3 was used in these experiments. The operating conditions were held constant at a mean pressure of 2.0 MPa and a frequency of 54 Hz. Using finite difference software called REGEN3.1, developed at NIST, and recent experiment results, we optimized a series of regenerators based on dimensions, materials and screen packing. The values used for calculating the thermal conduction through stacked screens by REGEN3.1 were based on recent experimental results from NIST. The regenerator tubes were designed using 316 stainless steel and titanium materials. The regenerator matrices investigated were 400-mesh and 500-mesh stainless steel screen. The valve settings for both orifices were adjusted to minimize the no-load temperature for all regenerators. A cooling capacity curve from 0 to 3 W was also determined. The performance of the pulse tube refrigerator using the different regenerators is discussed. The experimental results from the various regenerators are evaluated and compared with their corresponding numerically calculated coefficient of performance (COP) and regenerator design as determined by REGEN3.1. PMID:11543212

Lewis, M; Kuriyama, T; Xiao, J H; Radebaugh, R

1998-01-01

470

ALTERNATIVE TECHNOLOGIES FOR REFRIGERATION AND AIR-CONDITIONING APPLICATIONS  

EPA Science Inventory

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

471

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

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Hydrogen chloride, refrigerated liquid...114 and 120) § 179.102-17 Hydrogen chloride, refrigerated liquid. Each tank car used to transport hydrogen chloride, refrigerated liquid...

2014-10-01

472

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

Code of Federal Regulations, 2014 CFR

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

2014-10-01

473

Magnetic refrigeration at room temperature - from magnetocaloric materials to a prototype  

NASA Astrophysics Data System (ADS)

Based on the magnetocaloric effect, magnetic refrigeration at room temperature has for the past decade been a promising, environmentally friendly new energy technology predicted to have a significantly higher efficiency than the present conventional methods. However, so far only a few prototype refrigeration machines have been presented worldwide and there are still many scientific and technological challenges to be overcome. We report here on the MagCool project, which spans all the way from basic materials studies to the construction of a prototype. Emphasis has been on ceramic magnetocaloric materials, their shaping and graded composition for technological use. Modelling the performance of a permanent magnet with optimum use of the flux and relatively low weight, and designing and constructing a prototype continuous magnetic refrigeration device have also been major tasks in the project.

Theil Kuhn, L.; Pryds, N.; Bahl, C. R. H.; Smith, A.

2011-07-01