Sample records for r-134a refrigerant cooling

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

    SciTech Connect

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

    2007-01-01

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

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

    SciTech Connect

    Lowe, K.T.

    2005-10-07

    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.

  3. Absorption system based on the refrigerant R134a

    Microsoft Academic Search

    I Borde; M Jelinek; N. C Daltrophe

    1995-01-01

    The possibility of using 1,1,1,2-tetrafluoroethane (R134a) as a refrigerant in combination with different organic absorbents, such as dimethylether tetraethyleneglycol (DMETEG), N-methyl ?-caprolactam (MCL) or dimethyl-ethyleneurea (DMEU), in absorption units was investigated. The procedures in this paper are presented for the model working pair R134a-DMETEG. Temperature-pressure-concentration curves were constructed on the basis of vapour-liquid equilibrium measurements. Excess thermodynamic properties of the

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

    Microsoft Academic Search

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

    2012-01-01

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

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

    Microsoft Academic Search

    A. Stegou-Sagia; M. Damanakis

    2000-01-01

    Refrigerant mixtures may be used to solve the ozone layer depletion problem as they offer the optimum combination of favorable technical performance with environmentally acceptable behavior. This work reports the thermodynamic properties and characteristics of the binary mixtures R-32\\/R-134a in compositions 2080%, 3070%, 4060% by mass and of the ternary mixture R-407c: 23 wt% R-32 + 25 wt% R-125 +

  6. Two-phase flow boiling of R134a in a multi-microchannel heat sink for microprocessor cooling

    Microsoft Academic Search

    Yassir Madhour; Jonathan Olivier; Etienne Costa-Patry; Stephan Paredes; Bruno Michel; J. R. Thome

    2010-01-01

    The following study concentrates on two-phase flow boiling of refrigerant R134a inside two similar copper multi-microchannel heat sinks, one of which was designed for singlephase water cooling of microprocessors. The two-phase heat sink was composed of 100 parallel microchannels, 100 ?m wide, 680 ?m high, 15 mm long with 72 ?m-thick fins, and 63 parallel microchannels. Base heat fluxes and

  7. Flow Boiling of R134a in a Multi-Microchannel Heat Sink With Hotspot Heaters for Energy-Efficient Microelectronic CPU Cooling Applications

    Microsoft Academic Search

    Yassir Madhour; Jonathan Olivier; Etienne Costa-Patry; Stephan Paredes; Bruno Michel; John Richard Thome

    2011-01-01

    This paper focuses on two-phase flow boiling of refrigerant R134a inside a copper multi-microchannel heat sink for microelectronic central processing unit cooling applications. The heat sink is composed of 100 parallel microchannels, 100 m wide, 680 m high, and 15 mm long, with 72-m-thick fins separating the channels. The base heat flux was varied from 2.57 to 189 W\\/cm 2

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

    SciTech Connect

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

    2012-01-01

    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.

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

    Microsoft Academic Search

    Vineyard; Edward Allan

    2012-01-01

    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

  10. Formation Of CFC Alternative R134a Gas Hydrate

    Microsoft Academic Search

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

    1990-01-01

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

  11. Roughness and surface material effects on nucleate boiling heat transfer from cylindrical surfaces to refrigerants R-134a and R-123

    SciTech Connect

    Jabardo, Jose M. Saiz [Escuela Politecnica Superior, Universidad de la Coruna, Mendizabal s/n Esteiro, 15403 Ferrol, Coruna (Spain); Ribatski, Gherhardt; Stelute, Elvio [Department of Mechanical Engineering, Escola de Engenharia de Sao Carlos (EESC), University of Sao Paulo (USP), Av. Trabalhador Saocarlense 400 Centro, 13566-590 Sao Carlos, SP (Brazil)

    2009-04-15

    This paper presents results of an experimental investigation carried out to determine the effects of the surface roughness of different materials on nucleate boiling heat transfer of refrigerants R-134a and R-123. Experiments have been performed over cylindrical surfaces of copper, brass and stainless steel. Surfaces have been treated by different methods in order to obtain an average roughness, Ra, varying from 0.03 {mu}m to 10.5 {mu}m. Boiling curves at different reduced pressures have been raised as part of the investigation. The obtained results have shown significant effects of the surface material, with brass being the best performing and stainless steel the worst. Polished surfaces seem to present slightly better performance than the sand paper roughened. Boiling on very rough surfaces presents a peculiar behavior characterized by good thermal performance at low heat fluxes, the performance deteriorating at high heat fluxes with respect to smoother surfaces. (author)

  12. R-134a emissions from vehicles.

    PubMed

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

    2002-02-15

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

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

    Microsoft Academic Search

    Bilal Ahmed Qureshi; Syed M. Zubair

    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

  14. 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

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

    1990-01-01

    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.

  15. 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)

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

    1990-02-01

    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.

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

    Microsoft Academic Search

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

    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

  17. Ozone friendly binary blends R 32\\/R 134a and the ternary R 407b

    Microsoft Academic Search

    A. Stegou-Sagia; X. Kakatsios; M. Damanakis

    2004-01-01

    The objective of this paper is to present thermodynamic properties and characteristics of the binary refrigerant mixtures R 32\\/R 134a in compositions 20\\/80%, 30\\/70%, 40\\/60% by mass and of the ternary mixture R 407b: 10 wt% R 32+70 wt% R 125+20 wt% R 134a. A computer code has been developed and by use of a PengRobinson type equation of state,

  18. Predicting Heat Transfer in Long R-134a Filled Thermosyphons

    Microsoft Academic Search

    M. H. M. Grooten

    2009-01-01

    When traditional air-to-air cooling is too voluminous, heat exchangers with long thermosyphons offer a good alternative. Experiments with a single thermosyphon with a large length-to-diameter ratio (188) and filled with R-134a are presented and analyzed. Saturation temperatures, filling ratios and angles of inclination have been varied in wide ranges. A higher sensitivity of evaporation heat transfer coefficients on reduced pressure

  19. Defluorination of 1,1,1,2-tetrafluoroethane (R-134a) by rat hepatocytes.

    PubMed

    Olson, M J; Reidy, C A; Johnson, J T

    1990-02-14

    As part of its toxicological evaluation we assessed the in vitro metabolism of 1,1,1,2-tetrafluoroethane (R-134a), a non-ozone-depleting chemical likely to replace dichlorodifluoromethane (R-12) as an air-conditioning refrigerant. Hepatocyte suspensions in sealed flasks produced increasing quantities of F- (detected in the liquid media) as the headspace concentration of R-134a increased from 1% to 50% (balance of atmosphere 95% O2-5% CO2); the kinetics of defluorination suggested substrate-saturation. Little F- was detected in cultures without R-134a or in cell suspensions heated prior to addition of R-134a. Halothane (1,1,1-trichloro-2-bromo-2-chloro-ethane), although not defluorinated by hepatocytes maintained with 95% O2, inhibited defluorination of R-134a. Hepatocytes from phenobarbital-treated rats dehalogenated high (greater than or equal to 25%) concentrations of R-134a at greater rates than cells from untreated rats. These findings are consistent with the hypothesis that oxidative metabolism of R-134a by cytochrome P-450 can occur in vivo. PMID:2306253

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

    Microsoft Academic Search

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

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

  1. Oil cooled, hermetic refrigerant compressor

    DOEpatents

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

    1985-01-01

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

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

    SciTech Connect

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

    2013-08-01

    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.

  3. Computing Isentropic Flow Properties of Air/R-134a Mixtures

    NASA Technical Reports Server (NTRS)

    Kvaternik, Ray

    2006-01-01

    MACHRK is a computer program that calculates isentropic flow properties of mixtures of air and refrigerant R-134a (tetrafluoroethane), which are used in transonic aerodynamic testing in a wind tunnel at Langley Research Center. Given the total temperature, total pressure, static pressure, and mole fraction of R-134a in a mixture, MACHRK calculates the Mach number and the following associated flow properties: dynamic pressure, velocity, density, static temperature, speed of sound, viscosity, ratio of specific heats, Reynolds number, and Prandtl number. Real-gas effects are taken into account by treating the gases comprising the mixture as both thermally and calorically imperfect. The Redlich-Kwong equation of state for mixtures and the constant-pressure ideal heat-capacity equation for the mixture are used in combination with the departure- function approach of thermodynamics to obtain the equations for computing the flow properties. In addition to the aforementioned calculations for air/R-134a mixtures, a research version of MACHRK can perform the corresponding calculations for mixtures of air and R-12 (dichlorodifluoromethane) and for air/SF6 mixtures. [R-12 was replaced by R-134a because of environmental concerns. SF6 has been considered for use in increasing the Reynolds-number range.

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

    PubMed

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

    2014-08-18

    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

  5. Microscopic structure of liquid 1-1-1-2-tetrafluoroethane (R134a) from Monte Carlo simulation.

    PubMed

    Do, Hainam; Wheatley, Richard J; Hirst, Jonathan D

    2010-10-28

    1-1-1-2-tetrafluoroethane (R134a) is one of the most commonly used refrigerants. Its thermophysical properties are important for evaluating the performance of refrigeration cycles. These can be obtained via computer simulation, with an insight into the microscopic structure of the liquid, which is not accessible to experiment. In this paper, vapour-liquid equilibrium properties of R134a and its liquid microscopic structure are investigated using coupled-decoupled configurational-bias Monte Carlo simulation in the Gibbs ensemble, with a recent potential [J. Phys. Chem. B 2009, 113, 178]. We find that the simulations agree well with the experimental data, except at the vicinity of the critical region. Liquid R134a packs like liquid argon, with a coordination number in the first solvation shell of 12 at 260 K. The nearest neighbours prefer to be localized in three different spaces around the central molecule, in such a manner that the dipole moments are in a parallel alignment. Analysis of the pair interaction energy shows clear association of R134a molecules, but no evidence for C-HF type hydrogen bonding is found. The above findings should be of relevance to a broad range of fluoroalkanes. PMID:20830386

  6. Feasibility of cool storage systems in refrigeration

    NASA Astrophysics Data System (ADS)

    Elmahgary, Yehia; Kekkonen, Veikko; Laitinen, Ari; Pihala, Hannu

    1989-05-01

    In the present report, the economic viability and technical feasibility of selected cool storage systems are considered. Cool storage has clear potential for several applications: in connection with air-conditioning systems, domestic refrigerating and freezing systems; commercially e.g., in the dairy and vegetable industries; and in deep freezing, as in the meat industry. Air-conditioning has limited significance in Finland. For this reason it was not investigated in this study. In domestic refrigeration and freezing two systems were investigated; a controlled cooling/heating system and a simple built-in system in individual refrigerators and freezers. The central cooling/heating system in houses was found to be economically unattractive. It also has several technical drawbacks. The simple built-in system appeared to be promising. The amount of savings is rationally a function of the difference between day and night tariffs and the costs of installing an automatic switch and storage media. In the vegetable and dairy industries cool storage also has considerable potential. Several systems were investigated in this respect and compared to the conventional system. The cool storage system using Cristopia balls, one of the most common commercial systems available in Europe, was not economical at a tariff difference of 10 p/k Wh or more. Cool storage for freezing in meat plants was also investigated.

  7. A proposed new nuclear cooling refrigerator

    Microsoft Academic Search

    M. P. Enrico; S. N. Fisher; A. M. Gunault; I. E. Miller; G. R. Pickett; K. Torizuka; R. P. Turner; M. G. Ward

    1994-01-01

    Since the large Lancaster nuclear cooling refrigerator, conceived in 1978 and completed in 1981, is now well into its second decade we are planning a new machine. This paper outlines the main features and underlying philosophy of the new design based on experience gained over many years of operation with the current machine.

  8. Heat Pipe Technology for Refrigeration and Cooling

    Microsoft Academic Search

    H. F. Smirnov

    \\u000a A main goal of this review was an exchange of the essential ideas and practical problems of heat pipe technology use for refrigeration\\u000a and cooling, with respect to the following most perspective spotlights:\\u000a \\u000a \\u000a \\u000a 1.\\u000a \\u000a Heat pipes and especially loop heat pipes application as a safe external or internal thermal link.\\u000a \\u000a \\u000a \\u000a 2.\\u000a \\u000a Heat pipe technology as a base for refrigerating heat

  9. Investigation on the boiling heat transfer characteristics of R404A and R134a under stratified flow condition

    NASA Astrophysics Data System (ADS)

    Balachander, P.; Raja, B.

    2015-06-01

    An experimental investigation on the flow boiling heat transfer characteristics of R404A and R134a for low mass flux and heat flux conditions in a smooth horizontal tube is reported. Refrigerant saturation temperatures -15, -10, -5 and 0 C were considered for the flow boiling conditions. The influence of the mass flux, heat flux and saturation temperature on the heat transfer coefficients of R404A and R134a are discussed in detail. The predominant flow pattern for the tested conditions is confirmed to be the stratified-wavy flow. The study revealed that the heat transfer coefficient is a strong function of the heat flux, throughout the flow boiling process, and the nucleate boiling contribution is much higher for R404A compared to that of R134a. The heat transfer characteristic of R404A is compared with that of R134a, to understand their relative performance in low temperature appliances. A modified correlation for the flow boiling heat transfer coefficient of R404A is developed to fit the experimental results of R404A.

  10. Falling Films on Arrays of Horizontal Tubes with R-134a, Part I: Boiling Heat Transfer Results for Four Types of Tubes

    Microsoft Academic Search

    J.-F. Roques; J. R. Thome

    2007-01-01

    A new falling film heat transfer test facility has been built for the measurement of local heat transfer coefficients on a vertical array of horizontal tubes, including flow visualization capabilities, for use with refrigerants. Presently, the facility has been used for evaporation tests on four types of tubes at three tube pitches and three nominal heat flux levels for R-134a

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

    DOEpatents

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

    2006-02-07

    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.

  12. Improved Regenerative Sorbent-Compressor Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1992-01-01

    Conceptual regenerative sorbent-compressor refrigerator attains regeneration efficiency and, therefore, overall power efficiency and performance greater than conventional refrigerators. Includes two fluid loops. In one, CH2FCF3 (R134a) ciculates by physical adsorption and desorption in four activated-charcoal sorption compressors. In other, liquid or gas coolant circulated by pump. Wave of regenerative heating and cooling propagates cyclically like peristatic wave among sorption compressors and associated heat exchangers. Powered by electricity, oil, gas, solar heat, or waste heat. Used as air conditioners, refrigerators, and heat pumps in industrial, home, and automotive applications.

  13. The effect of lubricant concentration, miscibility, and viscosity on R134a pool boiling

    Microsoft Academic Search

    M. A Kedzierski

    2001-01-01

    This paper presents pool boiling heat transfer data for 12 different R134a\\/lubricant mixtures and pure R134a on a Turbo-BII-HP surface. The mixtures were designed to examine the effects of lubricant mass fraction, viscosity, and miscibility on the heat transfer performance of R134a. The magnitude of the effect of each parameter on the heat transfer was quantified with a regression analysis.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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 (30C). 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.

  15. Advanced Refrigerant-Based Cooling Technologies for Information and Communication Infrastructure (ARCTIC)

    SciTech Connect

    Todd Salamon

    2012-12-13

    Faster, more powerful and dense computing hardware generates significant heat and imposes considerable data center cooling requirements. Traditional computer room air conditioning (CRAC) cooling methods are proving increasingly cost-ineffective and inefficient. Studies show that using the volume of room air as a heat exchange medium is wasteful and allows for substantial mixing of hot and cold air. Further, it limits cabinet/frame/rack density because it cannot effectively cool high heat density equipment that is spaced closely together. A more cost-effective, efficient solution for maximizing heat transfer and enabling higher heat density equipment frames can be accomplished by utilizing properly positioned ?¢????phase change?¢??? or ?¢????two-phase?¢??? pumped refrigerant cooling methods. Pumping low pressure, oil-free phase changing refrigerant through microchannel heat exchangers can provide up to 90% less energy consumption for the primary cooling loop within the room. The primary benefits of such a solution include reduced energy requirements, optimized utilization of data center space, and lower OPEX and CAPEX. Alcatel-Lucent recently developed a modular cooling technology based on a pumped two-phase refrigerant that removes heat directly at the shelf level of equipment racks. The key elements that comprise the modular cooling technology consist of the following. A pump delivers liquid refrigerant to finned microchannel heat exchangers mounted on the back of equipment racks. Fans drive air through the equipment shelf, where the air gains heat dissipated by the electronic components therein. Prior to exiting the rack, the heated air passes through the heat exchangers, where it is cooled back down to the temperature level of the air entering the frame by vaporization of the refrigerant, which is subsequently returned to a condenser where it is liquefied and recirculated by the pump. All the cooling air enters and leaves the shelves/racks at nominally the same temperature. Results of a 100 kW prototype data center installation of the refrigerant-based modular cooling technology were dramatic in terms of energy efficiency and the ability to cool high-heat-density equipment. The prototype data center installation consisted of 10 racks each loaded with 10 kW of high-heat-density IT equipment with the racks arranged in a standard hot-aisle/cold-aisle configuration with standard cabinet spacing. A typical chilled-water CRAC unit would require approximately 16 kW to cool such a heat load. In contrast, the refrigerant-based modular cooling technology required only 2.3 kW of power for the refrigerant pump and shelf-level fans, a reduction of 85 percent. Differences in hot-aisle and cold-aisle temperature were also substantially reduced, mitigating many issues that arise in purely air-based cooling systems, such as mixing of hot and cold air streams, or from placing high-heat-density equipment in close proximity. The technology is also such that it is able to retro-fit live equipment without service interruption, which is particularly important to the large installed ICT customer base, thereby providing a means of mitigating reliability and performance concerns during the installation, training and validation phases of product integration. Moreover, the refrigerant used in our approach, R134a, is a widely-used, non-toxic dielectric liquid which, unlike water, is non-conducting and non-corrosive and will not damage electronics in the case of a leak?¢????a triple-play win over alternative water-based liquid coolant technologies. Finally, through use of a pumped refrigerant, pressures are modest (~60 psi), and toxic lubricants and oils are not required, in contrast to compressorized refrigerant systems?¢????another environmental win. Project Activities - The ARCTIC project goal was to further develop an

  16. page 1 of 4 TkF Vrmeteknik Refrigeration / Kylteknik

    E-print Network

    Zevenhoven, Ron

    humidity RH % 10 60 Enthalpy h kJ/kg dry air Absolute humidity g/kg dry air b. Determine the heating devices. 205. A vapour-compression system that uses refrigerant R-134a must be tested to determine optimal 2. 10C sub-cooling, 10C super-heat b. Which of two cases has the best COPR? (6+2=8 p.) For data

  17. Flow regimes and two-phase pressure gradient in horizontal straight tubes: Experimental results for HFO1234yf, R-134a and R-410A

    Microsoft Academic Search

    Miguel Padilla; Rmi Revellin; Philippe Haberschill; Ahmed Bensafi; Jocelyn Bonjour

    2011-01-01

    Two-phase flow regime visualizations of HFO-1234yf and R-134a in a 6.70mm inner diameter glass straight tube have been simultaneous investigated by top and side views with a high speed high resolution camera. No major difference was observed between both refrigerants. HFO-1234yf flow regimes were satisfactorily predicted by the Wojtan et al. [1] flow pattern map. In addition, 819 pressure drop

  18. Hybrid vapor compression refrigeration system with an integrated ejector cooling cycle

    Microsoft Academic Search

    Yinhai Zhu; Peixue Jiang

    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

  19. High-temperature cooling power of the superfluid Stirling refrigerator

    SciTech Connect

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

    1995-02-01

    Above 1 Kelvin, the measured cooling power of the superfluid Stirling refrigerator is significantly greater than would be expected simply from a classical ideal gas of {sup 3}He quasiparticles. Analysis shows that this increased cooling power is due to the presence of the {sup 4}He excitations.

  20. Modeling the Water-R134a Partition Coefficients of Organic Solutes Using a Linear Solvation Energy Relationship

    E-print Network

    Lagalante, Anthony F.

    Modeling the Water-R134a Partition Coefficients of Organic Solutes Using a Linear Solvation Energy solvation energy relationship (LSER) was developed to predict the measured water-R134a partitionVed: June 23, 1998; In Final Form: August 17, 1998 The water-R134a partition coefficients for a set of 11

  1. Carbon dioxide as an alternative refrigerant for automotive air conditioning systems

    Microsoft Academic Search

    G. D. Mathur

    2000-01-01

    Thermodynamic performance of a typical automotive air conditioning system has been simulated using carbon dioxide as the working fluid. The performance of the carbon dioxide system is compared with a base case with R-134a as the refrigerant. A cooling capacity of 5.3 kW (1.5 ton) is used for this study. For the base case, evaporation and condensing temperatures of 6.7C

  2. Investigation of potential benefits of compressor cooling

    Microsoft Academic Search

    Xudong Wang; Yunho Hwang; Reinhard Radermacher

    2008-01-01

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

  3. Stability and activity of lipase in subcritical 1,1,1,2-tetrafluoroethane (R134a).

    PubMed

    Yu, Gang; Xue, Yong; Xu, Wei; Zhang, Jing; Xue, Chang Hu

    2007-12-01

    The stability and activity of commercial immobilized lipase from Candida antarctica (Novozym 435) in subcritical 1,1,1,2-tetrafluoroethane (R134a) was investigated. The esterification of oleic acid with glycerol was studied as a model reaction in subcritical R134a and in solvent-free conditions. The results indicated that subcritical R134a treatment led to significant increase of activity of Novozym 435, and a maximum residual activity of 300% was measured at 4 MPa, 30 degrees C after 7 h incubation. No deactivation of Novozym 435 treated with subcritical R134a under different operation factors (pressure 2-8 MPa, temperature 30-60 degrees C, incubation time 1-12 h, water content 1:1, 1:2, 1:5 enzyme/water, depressurization rate 4 MPa/1 min, 4 MPa/30 min, 4 MPa/90 min) was observed. While the initial reaction rate was high in subcritical R134a, higher conversion was obtained in solvent-free conditions. Though the apparent conversion of the reaction is lower in subcritical R134a, it is more practicable, especially at low enzyme concentrations desired at commercial scales. PMID:17909872

  4. Cooling Load Density Optimization of an Irreversible Simple Brayton Refrigerator

    Microsoft Academic Search

    Shengbing Zhou; Lingen Chen; Fengrui Sun; Chih Wu

    2002-01-01

    The performance optimization of an irreversible simple Brayton refrigerator coupled to constant-temperature heat reservoirs\\u000a is carried out by taking the cooling load density, i.e., the ratio of cooling load to the maximum specific volume in the cycle,\\u000a as the optimization objective using finite-time thermodynamics (FTT) or entropy generation minimization (EGM) in this paper.\\u000a The analytical formulae about the relations between

  5. Floating loop method for cooling integrated motors and inverters using hot liquid refrigerant

    DOEpatents

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

    2007-03-20

    A method for cooling vehicle components using the vehicle air conditioning system comprising the steps of: tapping the hot liquid refrigerant of said air conditioning system, flooding a heat exchanger in the vehicle component with said hot liquid refrigerant, evaporating said hot liquid refrigerant into hot vapor refrigerant using the heat from said vehicle component, and returning said hot vapor refrigerant to the hot vapor refrigerant line in said vehicle air conditioning system.

  6. Maximum cooling and maximum efficiency of thermoacoustic refrigerators

    NASA Astrophysics Data System (ADS)

    Tartibu, L. K.

    2015-06-01

    This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26, 48, 70 and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100, 200, 300, 400, 500 and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.

  7. Superfluid JouleThomson Refrigeration, a New Concept for Cooling Below 2 Kelvin

    Microsoft Academic Search

    J. G. Brisson

    2000-01-01

    A new type of sub-Kelvin refrigerator, the superfluid JouleThomson refrigerator is discussed. The refrigerator uses the circulation of the 3He component of a liquid 3He4He mixture through a throttle to provide cooling to temperatures of 0.5 K. A simple analytical model is developed to predict the cooling power for this refrigerator as function of temperature. In addition, cooling power predictions

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

    Microsoft Academic Search

    Wen Wu; Peipei Chen; Barclay G. Jones; Ty A. Newell

    2006-01-01

    The observation of sub-cooled flow film boiling was performed on a single-side-heated flat heat exchanger by using refrigerant R134a as the testing fluid. A stable vapor film was observed with the co-existence of sub-cooled bulk liquid. Vapor bubbles might release from the film, with the number and frequency changing under different conditions. The purpose of this paper is to describe

  9. Computer model for air-cooled refrigerant condensers with specified refrigerant circuiting

    SciTech Connect

    Ellison, R.D.; Creswick, F.A.; Fischer, S.K.; Jackson, W.L.

    1981-01-01

    A computer model for an air-cooled refrigerant condensor is presented; the model is intended for use in detailed design analyses or in simulation of the performance of existing heat exchangers that have complex refrigerant circuiting or unusual air-side geometries. The model relies on a tube-by-tube computational approach calculating the thermal and fluid-flow performance of each tube in the heat exchanger individually, using local temperatures and heat transfer coefficients. The refrigerant circuiting must be specified; the joining or branching of parallel circuits is accommodated using appropriate mixing expressions. Air-side heat exchange correlations may be specified so that various surface geometries can be investigated. Results of the analyses of two condensers are compared to experiment.

  10. Active Cooling for Downhole Instrumentation: Miniature Thermoacoustic Refrigerator.

    NASA Astrophysics Data System (ADS)

    Bennett, Gloria Adame

    1991-02-01

    A miniature active cooling system capable of providing multi-watt refrigeration for thermally protecting downhole instruments used in hot geothermal wells is researched, developed and designed. The engineering design process is used to develop design criteria and design constraints and to select potential refrigeration processes. A literature search identifies nine physical and chemical processes and twenty six systems appropriate for a feasibility study. Each refrigeration process is investigated to search for suitable high temperature components and a refrigerant, thereby eliminating only three processes and nine systems. Consistent analysis of an ideal thermodynamic cycle for each of the six remaining refrigeration processes further reduces the choices to three processes and seven systems. Final selection requires consideration of refrigerator and geothermal logging system thermal, mechanical and electrical interactions to define failure modes, insure compatibility with existing hardware, and allow adaptability to changes in design criteria. Results of calculations from postulated design criteria changes provide insight into design simplicity and data for further selection. A decision model is constructed and used to organize design constraints and criteria and sort out those useful for making a final selection. Final selection is based on maximizing system simplicity and providing graceful degradation in case of refrigerator failure. The consistent design, systematic analysis and unbiased selection process represent a body of research results that is new to this technology and provides a potential for advance not realized to date. The selected thermoacoustic process and the designed refrigeration system are analyzed in detail, with numerical models constructed for each subsystem, and component and for the component interactions. The thermoacoustic wave equation is extended to allow sloped rather than parallel acoustic plates. This extension increases acoustic power and reduces dissipative losses. The resonator losses model is extended for rectangular geometry and sloped stacks to aid in reducing viscous losses. A modular layered resonator design separates high temperature and high pressure vessel operating problems and provides adaptability to changes in operating conditions. A miniature electric resistance heater and two sets of stacked micro heat pipes at each acoustic stack leading or trailing edge provide localized high flux heat transfer. The micro heat pipe design represents an extension in micro heat pipe construction technology to avoid typical wicking limits. The miniature thermoacoustic refrigerator design provides long term active cooling for downhole instruments and represents a promising and substantial advancement in downhole thermal protection technology.

  11. Transient phenomena in a low cooling thermoacoustic refrigerator

    NASA Astrophysics Data System (ADS)

    Dhuley, R. C.; Atrey, M. D.

    2014-01-01

    A one-dimensional theoretical model is developed to describe the transient state phenomena in a low cooling standing wave Thermoacoustic Refrigerator. The model is based on the Linear Theory of Thermoacoustics. It uses Implicit Finite Difference method to calculate the temporal evolution of temperature and steady state temperature distribution in the refrigerator stack and the resonator. The cold temperatures predicted by the model are compared with those obtained by techniques given in literature, and show a very good match. Due to simplistic assumptions in the model and its one-dimensional nature, the cooldown rates are shown to be very fast compared to other experimental findings in literature. It is also seen that the resonator takes a long time to cool down compared to the stack.

  12. Combined refrigeration system with a liquid pre-cooling heat exchanger

    DOEpatents

    Gaul, Christopher J.

    2003-07-01

    A compressor-pump unit for use in a vapor-compression refrigeration system is provided. The compressor-pump unit comprises a driving device including a rotatable shaft. A compressor is coupled with a first portion of the shaft for compressing gaseous refrigerant within the vapor-compression refrigeration system. A liquid pump is coupled with a second portion of the shaft for receiving liquid refrigerant having a first pressure and for discharging the received liquid refrigerant at a second pressure with the second pressure being higher than the first pressure by a predetermined amount such that the discharged liquid refrigerant is subcooled. A pre-cooling circuit is connected to the liquid pump with the pre-cooling circuit being exposed to the gaseous refrigerant whereby the gaseous refrigerant absorbs heat from the liquid refrigerant, prior to the liquid refrigerant entering the liquid pump.

  13. Uniform temperature cooling power of the superfluid stirling refrigerator

    SciTech Connect

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

    1996-06-01

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

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

    NASA Technical Reports Server (NTRS)

    Kvaternik, Raymond G.

    2000-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-10-01

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

  16. Open airvapor compression refrigeration system for air conditioning and hot water cooled by cool water

    Microsoft Academic Search

    Shaobo Hou; Huacong Li; Hefei Zhang

    2007-01-01

    This paper presents an open airvapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6C. Its refrigeration depends mainly on both air and

  17. Two-Phase Frictional Pressure Drop Multipliers for SUVA R-134a Flowing in a Rectangular Duct

    SciTech Connect

    P Vassallo; K Keller

    2004-12-13

    The adiabatic two-phase frictional multipliers for SUVA, R-134a flowing in a rectangular duct (with D{sub H} = 4.8 mm) have been measured for 3 nominal system pressures (0.9 MPa, 1.38 MPa and 2.41 MPa) and 3 nominal mass fluxes (510, 1020 and 2040 kg/m{sup 2}/s). The data is compared with several classical correlations to assess their predictive capabilities. The Lockhart-Martinelli model gives reasonable results at the lowest pressure and mass flux, near the operating range of most refrigeration systems, but gives increasingly poor comparisons as the pressure and mass flux is increased. The Chisholm B-coefficient model is found to best predict the data over the entire range of test conditions; however, there is significant disagreement at the highest pressure tested (with the model over predicting the data upwards of 100% for some cases). The data shows an increased tendency toward homogeneous flow as the pressure and flow rate are increased, and in fact the homogeneous model best predicts the bulk of the data at the highest pressure tested.

  18. Nucleate pool boiling from coated surfaces in saturated R-134a and R-407c

    Microsoft Academic Search

    Shou-Shing Hsieh; Chun-Jen Weng

    1997-01-01

    Pool nucleate boiling heat transfer experiments from coated surfaces immersed in saturated R-134a and R-407c with porous aluminum, copper, molybdenum, and pitted coating on a copper surface were conducted. The influence of coating thickness and porosity on heat transfer and boiling hysteresis were studied. The enhanced surface heat transfer coefficients are 2.5 times higher than those of the smooth surface.

  19. Experimental evaluation of the internal heat exchanger influence on a vapour compression plant energy efficiency working with R22, R134a and R407C

    Microsoft Academic Search

    J. Navarro-Esbr; R. Cabello; E. Torrella

    2005-01-01

    Internal or liquid-suction heat exchangers are used in many refrigeration and air conditioning systems based on the vapour compression cycle, with the basic objective of assuring the entrance of refrigerant in liquid phase to the expansion device. This purpose is achieved by exchanging energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These

  20. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  1. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  2. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  3. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  4. 40 CFR 82.36 - Approved refrigerant handling equipment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

  5. Prediction of heat transfer coefficient during condensation of water and R-134a on single horizontal integral-fin tubes

    Microsoft Academic Search

    Ravi Kumar; H. K. Varma; Bikash Mohanty; K. N. Agrawal

    2002-01-01

    This paper presents a few salient features of an investigation carried out to study the heat transfer augmentation during condensation of water and R-134a vapor on horizontal integral-fin tubes. The experimental investigation was performed on two different experimental set-ups for water and R-134a. The test-sections were manufactured by machining fins over plain copper tubes of 24.4 0.6 mm outside

  6. Mass recovery adsorption refrigeration cycleimproving cooling capacity

    Microsoft Academic Search

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

    2004-01-01

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

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

    Microsoft Academic Search

    Li Xiaoyan; Yang Shuting; Zhou Dong

    2010-01-01

    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

  8. Refrigerant-Free Air Conditioning: Completely Safe, Environmentally-Friendly Cooling

    Microsoft Academic Search

    Paul Frenger

    2012-01-01

    Refrigerants for air conditioning universally have serious environmental or human-toxic side effects. Compressed, pure air may be substituted as an environmentally-friendly, safe refrigerating fluid using a vortex tube cooling device. Freezing temperatures can be produced. Various compressor technologies, control systems and efficiency enhancements are discussed.

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

    E-print Network

    Zuo, Z.; Hu, W.

    2006-01-01

    ICEBO2006, Shenzhen, China Building Commi ssioning for Energy Efficiency and Comfort, Vol.VI-7-3 Energy Efficiency Evaluation of Refrigeration Technologies in Combined Cooling, Heating and Power Systems Zheng Zuo WenBin Hu...

  10. Sub-cooled liquid nitrogen cryogenic system with neon turbo-refrigerator for HTS power equipment

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Hirai, H.; Nara, N.; Ozaki, S.; Hirokawa, M.; Eguchi, T.; Hayashi, H.; Iwakuma, M.; Shiohara, Y.

    2014-01-01

    We developed a prototype sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The system consists of a neon turbo-Brayton refrigerator with a LN sub-cooler and LN circulation pump unit. The neon refrigerator has more than 2 kW cooling power at 65 K. The LN sub-cooler is a plate-fin type heat exchanger and is installed in a refrigerator cold box. In order to carry out the system performance tests, a dummy cryostat having an electric heater was set instead of a HTS power equipment. Sub-cooled LN is delivered into the sub-cooler by the LN circulation pump and cooled within it. After the sub-cooler, sub-cooled LN goes out from the cold box to the dummy cryostat, and comes back to the pump unit. The system can control an outlet sub-cooled LN temperature by adjusting refrigerator cooling power. The refrigerator cooling power is automatically controlled by the turbo-compressor rotational speed. In the performance tests, we increased an electric heater power from 200 W to 1300 W abruptly. We confirmed the temperature fluctuation was about 1 K. We show the cryogenic system details and performance test results in this paper.

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

    SciTech Connect

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

    1993-04-01

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

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

    SciTech Connect

    ANDREWS, J.W.

    2001-04-01

    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.

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

    SciTech Connect

    Vineyard, E.A.

    1991-01-01

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

  14. A Numerical Estimate of Flexible Short-tube Flow and Deformation with R-134a and R-410a

    E-print Network

    Bassiouny, R.; O'Neal, D.

    ), and Drucker and Abbott (1993). LITERATURE REVIEW Much of the previous work on short-tubes has focused on rigid short-tubes. This has included studies of R-22 (Aaron and Domanski 1990; Kim and ONeal 1994a), R-134a (Kim and ONeal 1994b), and R-410a (Payne... and ONeal 1999). Three recent studies have focused on flexible short-tubes: Kim et al. (2002), Bassiouny and ONeal (2002), and Bassiouny A Numerical Estimate of Flexible Short-Tube Flow and Deformation with R-134a and R-410a Ramadan Bassiouny, Ph...

  15. Two-phase refrigerant flow instability analysis and active control in transient electronics cooling systems

    E-print Network

    Peles, Yoav

    -generation electronic systems, such as radar, di- rected-energy lasers, and electromagnetic weapons, will exceed 1000 WTwo-phase refrigerant flow instability analysis and active control in transient electronics cooling Accepted 26 July 2010 Available online 21 August 2010 Keywords: Electronics cooling Flow instability

  16. Adaptive cooling on the basis of pulse tube refrigerators

    Microsoft Academic Search

    Gnter Thummes; Christoph Heiden

    1999-01-01

    Adapting the cryocooler to the particular requirements of a given application is a task that is gaining more and more attention.\\u000a Due to several inherent features of the pulse tube cooler, this type of refrigerator appears to be a good candidate for this\\u000a purpose. This is illustrated in this paper for the case of single and multi-stage pulse tube refrigerators

  17. Performance comparison between alternative and phased-out refrigerants

    Microsoft Academic Search

    K. M. K. Abu-Abdou

    1994-01-01

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

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

    Microsoft Academic Search

    Victor Chiriac; Florea Chiriac

    2010-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    de Urquijo, J.; Jurez, A. M.; Basurto, E.; Hernndez-vila, J. L.

    2009-02-01

    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.

  1. Cryogen-free dilution refrigerator with separate 1K cooling circuit.

    NASA Astrophysics Data System (ADS)

    Uhlig, Kurt

    2012-06-01

    Helium-3,4 dilution refrigeration is indispensable for low temperature science and engineering as it is the only method which provides temperatures between 0.3 K and 0.005 K for unlimited working periods. Cryogen-free dilution refrigerators are about to replace traditional cryostats with liquid helium precooling. The dilution circuit is always precooled by a two-stage pulse tube cryocooler; therefore, refrigeration capacities are available to the experimentalist at the temperatures of the two stages of the pulse tube cooler, and furthermore at three temperatures of the dilution circuit (~ 0.7 K - still, 0.1 K - heat exchanger, ~ 0.01 K - mixing chamber). However, there are quite a few applications (e.g. quantum information processing or astro-physics) where the cooling power of the still near ~ 1K is not sufficient to cool amplifiers and electric lines. In our work we present a dilution refrigerator where a He-4 cooling circuit has been added in the cryostat to the dilution circuit. This He-4 circuit provides up to 60 mW of refrigeration capacity in addition to the cooling capacity of ~ 30 mW of the still. The dilution circuit and the 1Kcircuit can be operated together or separately.

  2. Evaporation heat transfer and flow characteristics of R-134a flowing through internally grooved tubes

    NASA Astrophysics Data System (ADS)

    Wongwises, Somchai; Laohalertdecha, Suriyan; Kaew-On, Jatuporn; Duangthongsuk, Weerapun; Aroonrat, Kanit; Sakamatapan, Kittipong

    2011-06-01

    This article describes experimental investigations of the heat transfer coefficient and pressure drop of R-134a flowing inside internally grooved tubes. The test tubes are one smooth tube and four grooved tubes. All test tubes are made from type 304 stainless steel, have an inner diameter of 7.1 mm, are 2,000 mm long and are installed horizontally. The test section is uniformly heated by a DC power supply to create evaporation conditions. The groove depth of all grooved tubes is fixed at 0.2 mm. The experimental conditions are conducted at saturation temperatures of 20, 25 and 30C, heat fluxes of 5, 10 and 15 kW/m2, and mass fluxes of 300, 500 and 700 kg/m2 s. The effects of groove pitch, mass flux, heat flux, and saturation temperature on heat transfer coefficient and frictional pressure drop are discussed. The results illustrate that the grooved tubes have a significant effect on the heat transfer coefficient and frictional pressure drop augmentations.

  3. Heating surface materials effect on subcooled flow boiling heat transfer of R134a

    SciTech Connect

    Ling Zou; Barclay G. Jones

    2012-11-01

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

  4. Tetrafluoroethane (R134a) hydrate formation within variable volume reactor accompanied by evaporation and condensation.

    PubMed

    Jeong, K; Choo, Y S; Hong, H J; Yoon, Y S; Song, M H

    2015-03-01

    Vast size hydrate formation reactors with fast conversion rate are required for the economic implementation of seawater desalination utilizing gas hydrate technology. The commercial target production rate is order of thousand tons of potable water per day per train. Various heat and mass transfer enhancement schemes including agitation, spraying, and bubbling have been examined to maximize the production capacities in scaled up design of hydrate formation reactors. The present experimental study focused on acquiring basic knowledge needed to design variable volume reactors to produce tetrafluoroethane hydrate slurry. Test vessel was composed of main cavity with fixed volume of 140 ml and auxiliary cavity with variable volume of 0 ? 64 ml. Temperatures at multiple locations within vessel and pressure were monitored while visual access was made through front window. Alternating evaporation and condensation induced by cyclic volume change provided agitation due to density differences among water and vapor, liquid and hydrate R134a as well as extended interface area, which improved hydrate formation kinetics coupled with latent heat release and absorption. Influences of coolant temperature, piston stroke/speed, and volume change period on hydrate formation kinetics were investigated. Suggestions of reactor design improvement for future experimental study are also made. PMID:25832270

  5. Tetrafluoroethane (R134a) hydrate formation within variable volume reactor accompanied by evaporation and condensation

    NASA Astrophysics Data System (ADS)

    Jeong, K.; Choo, Y. S.; Hong, H. J.; Yoon, Y. S.; Song, M. H.

    2015-03-01

    Vast size hydrate formation reactors with fast conversion rate are required for the economic implementation of seawater desalination utilizing gas hydrate technology. The commercial target production rate is order of thousand tons of potable water per day per train. Various heat and mass transfer enhancement schemes including agitation, spraying, and bubbling have been examined to maximize the production capacities in scaled up design of hydrate formation reactors. The present experimental study focused on acquiring basic knowledge needed to design variable volume reactors to produce tetrafluoroethane hydrate slurry. Test vessel was composed of main cavity with fixed volume of 140 ml and auxiliary cavity with variable volume of 0 64 ml. Temperatures at multiple locations within vessel and pressure were monitored while visual access was made through front window. Alternating evaporation and condensation induced by cyclic volume change provided agitation due to density differences among water and vapor, liquid and hydrate R134a as well as extended interface area, which improved hydrate formation kinetics coupled with latent heat release and absorption. Influences of coolant temperature, piston stroke/speed, and volume change period on hydrate formation kinetics were investigated. Suggestions of reactor design improvement for future experimental study are also made.

  6. 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

    Uhrhan, S.; Gerber, A.

    2012-01-01

    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...

  7. Modeling and energy simulation of the variable refrigerant flow air conditioning system with water-cooled condenser under cooling conditions

    Microsoft Academic Search

    Yueming Li; Jingyi Wu; Sumio Shiochi

    2009-01-01

    As a new system, variable refrigerant flow system with water-cooled condenser (water-cooled VRF) can offer several interesting characteristics for potential users. However, at present, its dynamic simulation simultaneously in association with building and other equipments is not yet included in the energy simulation programs. Based on the EnergyPlus's codes, and using manufacturer's performance parameters and data, the special simulation module

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

    SciTech Connect

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

    2007-01-01

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

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

    SciTech Connect

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

    2014-01-01

    In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. This paper reports one of the Oak Ridge National Laboratory (ORNL) contributions to AREP. It compares performance of alternative refrigerants to that of R-410A and R-404A for heat pump and medium temperature applications, respectively. The alternatives reported in this paper are: R-32, DR-5, and L-41a for R-410A and ARM-31a, D2Y-65, L-40, and a mixture of R-32 and R-134a for R-404A. All performance comparison tests were conducted using scroll compressors of ~1.85 tons (6.5 kW) cooling capacity. Tests were conducted over a range of combinations of saturation suction and saturation discharge temperatures for both compressors. The tests showed that, in general, energy efficiency ratio (EER) and cooling capacity of R-410A alternative refrigerants were slightly lower than that of the baseline refrigerant with a moderate increases in discharge temperature. On the other hand, R-404A alternative refrigerants showed relative performance dependence on saturation suction and saturation discharge temperatures and larger increases in discharge temperature than for the R-410A alternatives. This paper summarizes the relative performance of all alternative refrigerants compared to their respective baseline.

  10. Construction of a dilution refrigerator cooled scanning force microscope A. E. Gildemeister,a

    E-print Network

    Ihn, Thomas

    nanostructures. Slip-stick motors allow sample coarse-positioning at base temperature. The construction, thermal coupled to the Dewar and mounted in the inner vacuum chamber IVC which contains about 1 cm3 He exchangeConstruction of a dilution refrigerator cooled scanning force microscope A. E. Gildemeister,a T

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

    Microsoft Academic Search

    K. S. Ong

    2010-01-01

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

  12. Solar-assisted R22 and R134a heat pump systems for low-temperature applications

    Microsoft Academic Search

    H. Z. Abou-Ziyan; M. F. Ahmed; M. N. Metwally; H. M. Abd El-Hameed

    1997-01-01

    The results of the simulations for a conventional heat pump, a conventional solar air heater and two serial solar-assisted heat pump (SAHP) systems are presented in this paper. The thermodynamic properties of R22, R404a and R134a are given in the form of correlations with correlation factors higher than 0.99. The performance characteristics of the heat pump are investigated using these

  13. Cooling of superconducting devices by liquid storage and refrigeration unit

    DOEpatents

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

    2013-08-20

    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.

  14. A robust platform cooled by superconducting electronic refrigerators

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  15. ARTI Refrigerant Database

    SciTech Connect

    Calm, J.M.

    1992-04-30

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

  16. 40 CFR Appendix D to Subpart B of... - SAE J2810 Standard for Recovery Only Equipment for HFC-134a Refrigerant

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  17. 40 CFR Appendix D to Subpart B of... - SAE J2810 Standard for Recovery Only Equipment for HFC-134a Refrigerant

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  18. Comparative performance analysis for endoreversible simple air refrigeration cycles considering ecological, exergetic efficiency and cooling load objectives

    Microsoft Academic Search

    Y. Tu; L. Chen; F. Sun; C. Wu

    2006-01-01

    On the basis of exergetic analysis, the performance analysis and optimisation of endoreversible simple air refrigeration cycles with constant-temperature heat reservoirs is carried out by using the finite-time thermodynamic method in this paper. The expressions for cooling load, ecological function and exergetic efficiency of the refrigeration cycle are derived. The influences of pressure ratio of the compressor and allocation of

  19. Assessment of adsorber bed designs in waste-heat driven adsorption cooling systems for vehicle air conditioning and refrigeration

    E-print Network

    Bahrami, Majid

    ) for vehicle air conditioning and refrigeration (A/CR) applications. Adsorber beds should be specifically conditioning and refrigeration Amir Sharafian, Majid Bahrami n Laboratory for Alternative Energy ConversionAssessment of adsorber bed designs in waste-heat driven adsorption cooling systems for vehicle air

  20. Refrigerator-freezer energy testing with alternative refrigerants

    SciTech Connect

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

    1989-01-01

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

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

    E-print Network

    Thin Film Solid State Refrigerators for Spot Cooling of Integrated Circuits Ali Shakouri, Daryoosh of California at Santa Cruz Santa Cruz, CA 95064-1077, USA Tel: (831) 459-3821 Fax: (831) 459-4829 ali

  2. Optical refrigeration breaks the Peltier barrier: cooling Yb:YLF to 155K

    Microsoft Academic Search

    Denis V. Seletskiy; Seth D. Melgaard; Mansoor Sheik-Bahae; Stefano Bigotta; Alberto Dilieto; Mauro Tonelli; Richard I. Epstein

    2010-01-01

    We demonstrate first cryogenic operation in a Ytterbium doped YLF crystal by means of an optical refrigeration. We have achieved cooling to 155 Kelvin absolute temperature with heat lift of 90 mW, exceeding performance of multi-stack thermo-electric coolers. This progress was possible by pumping the system near the Stark-manifold resonance of highly pure Yb:YLF crystal and careful thermal management in

  3. In situ refractometry for concentration measurements in refrigeration systems

    SciTech Connect

    Newell, T.A. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering

    1997-12-31

    An in situ refractometer was developed that is capable of measuring both the concentrations of oil in refrigerants, and the concentrations of aqueous coolant brines. A description of the technique, and example data are presented for R-134a/PAG oil, aqueous ethylene glycol, and aqueous propylene glycol solutions. The R-134a/PAG oil sensor data show a measurement sensitivity of less than 0.1% oil in the refrigerant, although error between data sets shows an uncertainty of approximately {+-}0.8%. Ethylene glycol and propylene glycol data show high signal level variations due to the large variation of the index of refraction between water and the glycols.

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

    SciTech Connect

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

    2012-12-01

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

  5. Binary refrigerantoil phase equilibrium using the simplified SAFT equation

    Microsoft Academic Search

    Angelo Lucia; Qing Luo

    2002-01-01

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

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

    SciTech Connect

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

    2009-11-15

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

  7. Thermodynamic evaluation of five alternative refrigerants in vapor-compression cycles

    Microsoft Academic Search

    G. S. Kazachki; C. L. Gage

    1991-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

    This paper presents experimental results of the concentration dependence of heat transfer coefficients for mixtures of R134a and polyolester (POE) oil under the conditions of pool nuc1eateboiling. The experiments are conducted by means of ah horizontal platinum wire at saturation tel11peraturesof 9, 19, and 29C and at oil concentrations from 0 to 8 mass%. The present results show that the boiling heat transfer coefficient for the system concerned decreases with increasing oil concentration as a whole but increases slightly at a low oil concentration of about 4 mass%. A correlation equation is also given as a function of heat flux, temperature and oil concentration to reproduce the experimental boiling heat transfer coefficient within an uncertainly of about15%.

  9. Continuous Magnetic Refrigerators for Cooling in the 0.05 to 10 K Range: Progress and Future Development

    NASA Technical Reports Server (NTRS)

    Shirron, Peter; DiPirro, Michael; Canavan, Edgar; Tuttle, James; King, Todd; Numazawa, Takenori

    2003-01-01

    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 magne$, 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. The drawback to single-shot ADRs is that the cooling power per unit mass is relatively low. Refrigerants that are suitable for low temperature operation necessarily have low magnetic ion density, and therefore low entropy density. Since ADRs store entropy, systems with even modest cooling powers (a few microwatts) at temperatures below 100 mK tend to be massive, averaging 10-15 kg.

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

    SciTech Connect

    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

    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.

  11. A Robust Cooling Platform for NIS Junction Refrigeration and sub-Kelvin Cryogenic Systems

    NASA Astrophysics Data System (ADS)

    Wilson, B.; Atlas, M.; Lowell, P.; Moyerman, S.; Stebor, N.; Ullom, J.; Keating, B.

    2014-08-01

    Recent advances in Normal metal-insulator-superconductor (NIS) tunnel junctions (Clark et al. Appl Phys Lett 86: 173508, 2005, Appl Phys Lett 84: 4, 2004) have proven these devices to be a viable technology for sub-Kelvin refrigeration. NIS junction coolers, coupled to a separate cold stage, provide a flexible platform for cooling a wide range of user-supplied payloads. Recently, a stage was cooled from 290 to 256 mK (Lowell et al. Appl Phys Lett 102: 082601 2013), but further mechanical and electrical improvements are necessary for the stage to reach its full potential. We have designed and built a new Kevlar suspended cooling platform for NIS junction refrigeration that is both lightweight and well thermally isolated; the calculated parasitic loading is pW from 300 to 100 mK. The platform is structurally rigid with a measured deflection of 25 m under a 2.5 kg load and has an integrated mechanical heat switch driven by a superconducting stepper motor with thermal conductivity G W/K at 300 mK. An integrated radiation shield limits thermal loading and a modular platform accommodates enough junctions to provide nanowatts of continuous cooling power. The compact stage size of 7.6 cm 8.6 cm 4.8 cm and overall radiation shield size of 8.9 cm 10.0 cm 7.0 cm along with minimal electrical power requirements allow easy integration into a range of cryostats. We present the design, construction, and performance of this cooling platform as well as projections for coupling to arrays of NIS junctions and other future applications.

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

    NASA Technical Reports Server (NTRS)

    Miller, Franklin K.

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

    2008-08-01

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

  14. ARTI Refrigerant Database

    SciTech Connect

    Calm, J.M.

    1992-11-09

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

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

    NASA Astrophysics Data System (ADS)

    Patel, Ashok B.

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

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

    SciTech Connect

    Green, Michael A.

    2007-08-27

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

  18. Current and future miniature refrigeration cooling technologies for high power microelectronics

    Microsoft Academic Search

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

    2002-01-01

    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

  19. Dipole moments of seven partially halogenated ethane refrigerants

    Microsoft Academic Search

    Christopher W. Meyer; Graham Morrison

    1991-01-01

    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 (CFCHF), μ = 1.563 {plus minus} 0.005 D; R134a (CFCHF), μ

  20. Use of a Joule-Thomson micro-refrigerator to cool a radio-frequency coil for magnetic resonance microscopy

    Microsoft Academic Search

    A. C. Wright; H. K. Song; D. M. Elliott; F. W. Wehrli

    2005-01-01

    A method is described for cryogenically cooling a rf detector coil, as used in high-resolution magnetic resonance imaging (MRI), to enhance image signal-to-noise ratio (SNR). By incorporating the rf coil into a Joule-Thomson micro-refrigerator, the coil is precision-cooled to 70 K using only a source of high-pressure nitrogen gas at room temperature, avoiding the need for liquid cryogens. The rf

  1. Prediction of heat transfer coefficients and friction factors for evaporation of R-134a flowing inside corrugated tubes

    NASA Astrophysics Data System (ADS)

    Laohalertdecha, S.; Aroonrat, K.; Dalkilic, A. S.; Mahian, O.; Kaewnai, S.; Wongwises, S.

    2014-04-01

    In this study, experimental and simulation studies of the evaporation heat transfer coefficient and pressure drop of R-134a flowing through corrugated tubes are conducted. The test section is a horizontal counter-flow concentric tube-in-tube heat exchanger 2.0 m in length. A smooth tube and corrugated tubes with inner diameters of 8.7 mm are used as the inner tube. The outer tube is made from a smooth copper tube with an inner diameter of 21.2 mm. The corrugation pitches used in this study are 5.08, 6.35, and 8.46 mm. Similarly, the corrugation depths are 1, 1.25, and 1.5 mm, respectively. The results show that the maximum heat transfer coefficient and pressure drop obtained from the corrugated tube are up to 22 and 19 % higher than those obtained from the smooth tube, respectively. In addition, the average difference of the heat transfer coefficient and pressure drop between the simulation model and experimental data are about 10 and 15 %, respectively.

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

    PubMed

    Steckel, H; Mller, B W

    1998-07-01

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

  3. Thermotile Refrigerators

    NASA Technical Reports Server (NTRS)

    Park, Brian V.

    1994-01-01

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

  4. Coherence-assisted single-shot cooling by quantum absorption refrigerators

    E-print Network

    Mark T. Mitchison; Mischa P. Woods; Javier Prior; Marcus Huber

    2015-04-07

    The extension of thermodynamics into the quantum regime has received much attention in recent years. A primary objective of current research is to find thermodynamic tasks which can be enhanced by quantum mechanical effects. With this goal in mind, we explore the finite-time dynamics of absorption refrigerators composed of three qubits. The aim of this finite-time cooling is to reach low temperatures as fast as possible and subsequently extract the cold particle to exploit it for information processing purposes. We show that the coherent oscillations inherent to quantum dynamics can be harnessed to reach temperatures that are colder than the steady state in orders of magnitude less time, thereby providing a fast source of low-entropy qubits. This effect demonstrates that quantum thermal machines can surpass classical ones, reminiscent of quantum advantages in other fields, and is applicable to a broad range of technologically important scenarios.

  5. Average Heat Transfer Coefficient for Pool Boiling of R-134a and R-123 on Smooth and Enhanced Tubes (RP1316)

    Microsoft Academic Search

    Evraam Gorgy; Steven Eckels

    2010-01-01

    This paper presents information about nucleate pool boiling of R-134a and R-123 on TBIIHP and TBIILP tubes, respectively, as well as on smooth tubes. This is the first phase of ASHRAE project RP-1316, Experimental Evaluation of Heat Transfer Impacts of Tube Pitch in a Highly Enhanced Surface Tube Bundle. Data were taken at a saturation temperature of 4.44C (40F). The

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

    PubMed

    Calvosa, Frank C; Lagalante, Anthony F

    2010-01-15

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

  7. Three-Dimensional Electro-Thermal Modeling of Thin Film Micro-Refrigerators for Site-Specific Cooling of VLSI ICs

    E-print Network

    -refrigerator integrated onto a chip. The model takes into account of the Peltier cooling and heating, Joule heating-Specific Cooling of VLSI ICs Je-Hyoung Park, Sung-Mo Kang, Yan Zhang, Kazuhiko Fukutani, Ali Shakouri Dept of "hot spots" is an important issue. Recently, a cooling technology based on heterostructure integrated

  8. Optimizing Cooling Tower Performance- Refrigeration Systems, Chemical Plants, and Power Plants all Have A Resource Quietly Awaiting Exploitation-Cold Water!!

    E-print Network

    Burger, R.

    1990-01-01

    OPTIMIZING COOLING TOWER PERFORMANCE REFRIGERATION SYSTEMS, CHEMICAL PLANTS, AND POWER PLANTS ALL HAVE A RESOURCE QUIETLY AWAITING EXPLOITATION - COLD WATER!! ROBERT BURGER President Burger and Associates, Inc. Dallas, Texas Cooling... Evaluation In Compressed Air Systems", Plant Engineering, June 1979. 4. Allied Chemical Corp., "The Pressure Enthalpy Diagram: It's Construction, Use, and Value" . 5. Burger, Robert, "Cooling Tower Technology", Chapter 8, 1979, Revised 1989. 6...

  9. ARTI Refrigerant Database

    NASA Astrophysics Data System (ADS)

    Cain, J. M.

    1993-04-01

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

  10. ARTI Refrigerant Database

    NASA Astrophysics Data System (ADS)

    Calm, J. M.

    1993-11-01

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

  11. ARTI Refrigerant Database

    SciTech Connect

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

    1993-04-30

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

  12. The LSST camera 500-watt -130C mixed refrigerant cooling system

    NASA Astrophysics Data System (ADS)

    Bowden, Gordon B.; Langton, Brian J.; Little, William A.; Powers, Jacob R.; Schindler, Rafe H.; Spektor, Sam

    2014-07-01

    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.

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

    SciTech Connect

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

    1993-04-09

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

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

    SciTech Connect

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

    1993-04-09

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

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

    Microsoft Academic Search

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

    1994-01-01

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

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

    Microsoft Academic Search

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

    1993-01-01

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

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

    Microsoft Academic Search

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

    1998-01-01

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

  18. Optimal synthesis of refrigeration cycles and selection of refrigerants

    Microsoft Academic Search

    Shankar Vaidyaraman; Costas D. Maranas

    1999-01-01

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

  19. Refrigeration for Cryogenic Sensors

    SciTech Connect

    Gasser, M.G.

    1983-12-01

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

  20. Refrigeration for Cryogenic Sensors

    NASA Technical Reports Server (NTRS)

    Gasser, M. G. (editor)

    1983-01-01

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

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

    Microsoft Academic Search

    A. Stegou-Sagia; M. Damanakis

    2004-01-01

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

  2. Performance evaluation of a refrigerant-charged integrated solar water heater in northern Nigeria

    Microsoft Academic Search

    Joseph Enaburekhan; Usman Tanko Yakasai

    2009-01-01

    The thermal performance of the refrigerant-charged integrated solar water heater was analyzed to show its applicability in Nigeria, using data of several sunny and cloudy days. This unit, having three identical small-scale solar water heating systems using refrigerants R-134a, R12, and ethanol, was constructed and tested side by side under various environmental and load conditions in the Department of Mechanical

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

    SciTech Connect

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

    2004-08-30

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

  4. Experimental performance of ozone-safe alternative refrigerants

    SciTech Connect

    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

    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.

  5. Refrigeration principles and systems: An energy approach

    Microsoft Academic Search

    Pita

    1984-01-01

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

  6. Refrigerator Based on Chemisorption

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1987-01-01

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

  7. Free-air: ambient air refrigeration system. Final report. [Use of outside air for cooling root cellars, etc

    SciTech Connect

    Not Available

    1983-11-10

    The purpose of the project was to partially fund the construction, installation and monitoring of prototype devices that work on the principle of ambient air refrigeration. We call these devices FREE-AIR devices because because they utilize a source of refrigeration that exists in abundance all around us here in Vermont (and elsewhere) for much of the year: cold outside air. This air is free and the electrical energy required to capture it, while not free, is at least not expensive when compared to conventional compressor-driven refrigeration equipment. Whether working alone or in conjunction with a compressor system, a FREE-AIR device thermostaticly senses both the temperature of the outdoors and of the space to be cooled and brings in coal outside air, when necessary, to maintain a constant temperature. One of the unexpected positive results of prototype number 7 and number 8 is that the basic design is suitable not only for residential root and wine cellars, but also for commercial applications in which it would work in conjunction eith conventional refrigeration equipment without the need for a direct electrical connection to that equipment. This means that a single self-contained unit could serve the needs of a wide market and be installed easily by anyone familiar with common carpentry tools without the need for an electrician. These are critical considerations for Vermont Iron when deciding if the FREE-AIR makes sense as an addition to our product line. While that decision has not been made at this time there is a strong possibility that a production model of the FREE-AIR will be available this coming winter.

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

    SciTech Connect

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

    1980-03-01

    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.

  9. Use of a Joule-Thomson micro-refrigerator to cool a radio-frequency coil for magnetic resonance microscopy

    NASA Astrophysics Data System (ADS)

    Wright, A. C.; Song, H. K.; Elliott, D. M.; Wehrli, F. W.

    2005-01-01

    A method is described for cryogenically cooling a rf detector coil, as used in high-resolution magnetic resonance imaging (MRI), to enhance image signal-to-noise ratio (SNR). By incorporating the rf coil into a Joule-Thomson micro-refrigerator, the coil is precision-cooled to 70K using only a source of high-pressure nitrogen gas at room temperature, avoiding the need for liquid cryogens. The rf coil is insulated by a glass vacuum dewar that permits its use in proximity to biological tissues. Design and operation of the cryogenic system are described and its performance is demonstrated in a 1.5T clinical MRI scanner with images of a water phantom and a sheep intervertebral disc specimen. SNR gains of two to three times were obtained, compared to a similar coil at room temperature. The potential of this technology for local high-resolution MRI is discussed.

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

    SciTech Connect

    Kotsubo, V.; Swift, G.W.

    1990-01-01

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

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

    E-print Network

    Miller, Franklin K., 1970-

    2005-01-01

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

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

    Microsoft Academic Search

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

    2009-01-01

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

  13. Discrimination and identification of a refrigerant gas in a humidity controlled atmosphere containing or not carbon dioxide: application to the electronic nose

    Microsoft Academic Search

    Claude Delpha; Martine Lumbreras; Maryam Siadat

    2004-01-01

    Atmospheric pollution and green house effects are now one of the major preoccupations to improve the general quality of life. With an electronic nose application we propose a system dedicated to the main detection of refrigerant Forane 134a (R134a) gas leakage in air conditioned systems and atmospheres. For our application based on a metal oxide type gas sensor array (six

  14. Superfluid Stirling refrigerator: A new method for cooling below 1 Kelvin

    Microsoft Academic Search

    V. Kotsubo; G. W. Swift

    1990-01-01

    We have invented and built a new type of cryocooler, which we call the superfluid Stirling refrigerator (SSR). The first prototype reached 0.6 K from a starting temperature of 1.2 K. The working fluid of the SSR is the (sup 3)He solute in a superfluid He(3) - He(4) solution. At low temperatures, the superfluid He(4) is in its quantum ground

  15. Energy simulation in the variable refrigerant flow air-conditioning system under cooling conditions

    Microsoft Academic Search

    Y. P. Zhou; J. Y. Wu; R. Z. Wang; S. Shiochi

    2007-01-01

    As a high-efficiency air-conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way in office buildings. However, there is no well-known energy simulation software available so far which can be used for the energy analysis of VRF. Based on the generic dynamic building energy simulation environment, EnergyPlus, a new VRF module is developed and the energy usage

  16. 46 CFR 154.1720 - Indirect refrigeration.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Design and Operating Requirements 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor...

  17. 46 CFR 154.1720 - Indirect refrigeration.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Design and Operating Requirements 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor...

  18. 46 CFR 154.1720 - Indirect refrigeration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Design and Operating Requirements 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor...

  19. Dual mixed refrigerant natural gas liquefaction with staged compression

    Microsoft Academic Search

    1985-01-01

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

  20. Combined thermionic-thermoelectric refrigerator

    Microsoft Academic Search

    X. C. Xuan

    2002-01-01

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

  1. Laser Cooling of a Semiconductor by 40 Kelvin: An Optical Refrigerator Based on Cadmium Sulfide Nanoribbons

    E-print Network

    Xiong, Qihua

    having high purity with proper spaced energy levels and a high external quantum efficiency. Due to those-LO phonon Frhlich interactions. Using a pump- probe luminescence thermometry technique to measure the local to improve the cooling efficiency and to reach a larger cooling temperature in a variety of the RE doped

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

    SciTech Connect

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

    2010-11-15

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

  3. Thermoacoustic refrigeration

    SciTech Connect

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

    1992-12-01

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

  4. A progress report on using bolometers cooled by adiabatic demagnetization refrigeration

    NASA Technical Reports Server (NTRS)

    Lesyna, L.; Roellig, T.; Savage, M.; Werner, Michael W.

    1989-01-01

    For sensitive detection of astronomical continuum radiation in the 200 micron to 3 mm wavelength range, bolometers are presently the detectors of choice. In order to approach the limits imposed by photon noise in a cryogenically cooled telescope in space, bolometers must be operated at temperatures near 0.1 K. Researchers report progress in building and using bolometers that operate at these temperatures. The most sensitive bolometer had an estimated noise equivalent power (NEP) of 7 x 10(exp 017) W Hz(exp -1/2). Researchers also briefly discuss the durability of paramagnetic salts used to cool the bolometers.

  5. Semiconductor-based optical refrigerator

    DOEpatents

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

    2002-01-01

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

  6. Refrigeration and air conditioning

    Microsoft Academic Search

    B. J. Brinkworth

    1977-01-01

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

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

    SciTech Connect

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

    2002-08-30

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

  8. Thermal and flow measurements of continuous cryogenic spray cooling

    Microsoft Academic Search

    Shou-Shing Hsieh; Huang-Hsiu Tsai

    2006-01-01

    The performance of single sprays for high heat flux cooling using R-134a was studied. The heat flux and heat transfer coefficient at the surface of a sprayed jet based on measurements of steady-state temperature gradients on a thin copper plate during continuous spraying. Meanwhile, the spray droplets flow characteristics was also quantified through laser doppler velocimetry (LDV) measurements to obtain

  9. Analyzing of Thermoelectric Refrigerator Performance

    Microsoft Academic Search

    Suwit Jugsujinda; Athorn Vora-ud; Tosawat Seetawan

    2011-01-01

    The refrigeration system of thermoelectric refrigerator (TER; 252535cm3) was fabricated by using a thermoelectric cooler (TEC; 44cm2) and applied electrical power of 40W. The TER has not cooling fan for the coldness circulates in the refrigerator. The temperature of TER was measured at ten points to check the cooling system. The current, differential temperature, time, and coefficient of performance (COP)

  10. Feed gas drier precooling in mixed refrigerant natural gas liquefaction processes

    Microsoft Academic Search

    Y. N. Liu; C. L. Newton

    1988-01-01

    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

  11. Transcritical carbon dioxide small commercial cooling applications analysis

    Microsoft Academic Search

    Luca Cecchinato; Marco Corradi

    2011-01-01

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

  12. Support of NASA ADR/ Cross-Enterprise NRA Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling from 10K to 50mK, Development of a Heat Switch

    NASA Technical Reports Server (NTRS)

    Richards, Paul L.

    2005-01-01

    Mechanical heat switches are used in conjunction with sorption refrigerators, adiabatic demagnetization refrigerators and for other cryogenic tasks including the pre-cooling cryogenic systems. They use a mechanical actuator which closes Au plated Cu jaws on an Au plated Cu bar. The thermal conductance in the closed position is essentially independent of the area of the jaws and proportional to the force applied. It varies linearly with T. It is approximately 10mW/K for 200 N at 1.5K. In some applications, the heat switch can be driven from outside the cryostat by a rotating rod and a screw. Such heat switches are available commercially from several sources. In other applications, including systems for space, it is desirable to drive the switch using a cold linear motor, or solenoid. Superconducting windings are used at temperatures s 4.2K to minimize power dissipation, but are not appropriate for pre-cooling a system at higher temperatures. This project was intended to improve the design of solenoid activated mechanical heat switches and to provide such switches as required to support the development of Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling from 10 K to 50 mK at GSFC. By the time funding began in 5/1/01, the immediate need for mechanical heat switches at GSFC had subsided but, at the same time, the opportunity had arisen to improve the design of mechanical heat switching by incorporating a "latching solenoid". In this device, the solenoid current is required only for changing the state of the switch and not during the whole time that the switch is closed.

  13. Fluorescent refrigeration

    DOEpatents

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

    1995-09-05

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

  14. Film Condensation of R-134a and R-236fa, Part 1: Experimental Results and Predictive Correlation for Single-Row Condensation on Enhanced Tubes

    Microsoft Academic Search

    Marcel Christians; Mathieu Habert; John R. Thome

    2010-01-01

    New predictive methods for falling film condensation on vertical arrays of horizontal tubes using different refrigerants are proposed, based on visual observations revealing that condensate is slung off the array of tubes sideways and significantly affects condensate inundation and thus the heat transfer process. For two types of three-dimensional enhanced tubes, advanced versions of the Wolverine Turbo-C and Wieland Gewa-C

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

    SciTech Connect

    NONE

    1995-01-01

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

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

    SciTech Connect

    Not Available

    1994-02-01

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

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

    SciTech Connect

    NONE

    1995-12-01

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

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

    E-print Network

    Ginzel, Matthew

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

  19. Energy Efficiency and Environmental Impact Analyses of Supermarket Refrigeration Systems

    SciTech Connect

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

    2013-01-01

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

  20. Experimental comparison of R22 with R417A performance in a vapour compression refrigeration plant subjected to a cold store

    Microsoft Academic Search

    C. Aprea; C. Renno

    2004-01-01

    In this paper, the performances of a vapour compression refrigeration plant using as working fluids R22 and its substitute R417A (R125\\/R134a\\/R600, 46.6\\/50\\/3.4% in mass) are experimentally studied. This type of plant is applied to a commercially available cold store, generally adopted for preservation of foodstuff. Its working is regulated by on\\/off cycles of the compressor, operating at the nominal frequency

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

    SciTech Connect

    Not Available

    1989-05-01

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

  2. Optimal operation of simple refrigeration cycles: Part I: Degrees of freedom and optimality of sub-cooling

    Microsoft Academic Search

    Jrgen Bauck Jensen; Sigurd Skogestad

    2007-01-01

    The paper focuses on the operation of simple refrigeration cycles. With equipment given, there are, from a control and operational point of view, five steady-state degrees of freedom; the compressor power, the heat transfer in the condenser, the heat transfer in the evaporator, the choke valve opening and the active charge in the cycle. Different designs for affecting the active

  3. Optimum allocation of heat transfer surface area for cooling load and COP optimization of a thermoelectric refrigerator

    Microsoft Academic Search

    Jun Luo; Lingen Chen; Fengrui Sun; Chih Wu

    2003-01-01

    The theory of finite time thermodynamics is applied to analyze and optimize the performance of a thermoelectric refrigerator, which is composed of multi-elements. For the fixed total heat transfer surface area of two heat exchangers, the ratio of the heat transfer surface area of the high temperature side heat exchanger to the total heat transfer surface area of the heat

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

    E-print Network

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

    2006-01-01

    As a high-efficiency air conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way into medium-sized office buildings. Based on a generic dynamic building energy simulation environment, EnergyPlus, a new...

  5. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    G. W. Swift; V. Y. Kotsubo

    1991-01-01

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

  6. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    Gregory W. Swift; Vincent Y. Kotsubo

    1992-01-01

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

  7. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    G. W. Swift; V. Y. Kotsubo

    1991-01-01

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

  8. Superfluid thermodynamic cycle refrigerator

    Microsoft Academic Search

    G. W. Swift; V. Y. Kotsubo

    1992-01-01

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

  9. Toxicity Data to Determine Refrigerant Concentration Limits

    SciTech Connect

    Calm, James M.

    2000-09-30

    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.

  10. Alternative refrigerants and refrigeration cycles for domestic refrigerators

    SciTech Connect

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

    1992-12-01

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

  11. Ideal orifice pulse tube refrigerator performance

    NASA Technical Reports Server (NTRS)

    Kittel, P.

    1992-01-01

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

  12. Pulse Tube Refrigerator

    NASA Astrophysics Data System (ADS)

    Matsubara, Yoichi

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

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

    Microsoft Academic Search

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

    2001-01-01

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

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

    Microsoft Academic Search

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

    2001-01-01

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

  15. Solar-powered cooling systems: Technical and economic analysis on industrial refrigeration and air-conditioning applications

    Microsoft Academic Search

    Umberto Desideri; Stefania Proietti; Paolo Sdringola

    2009-01-01

    In the last years, the growing demand for air conditioning has caused a significant increase in demand for primary energy resources. Solar-powered cooling is one of the technologies which allows to obtain, by using the renewable solar source, an important energy saving compared to traditional air conditioning plants. The paper describes different technical installations for solar cooling, their way of

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    SciTech Connect

    Huttenlocher, D.F.

    1992-10-09

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

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

    SciTech Connect

    Huttenlocher, D.F.

    1992-10-09

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

  19. Adsorption Refrigeration System

    SciTech Connect

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

    2011-01-01

    Adsorption refrigeration is an environmentally friendly cooling technology which could be driven by recovered waste heat or low-grade heat such as solar energy. In comparison with absorption system, an adsorption system has no problems such as corrosion at high temperature and salt crystallization. In comparison with vapor compression refrigeration system, it has the advantages of simple control, no moving parts and less noise. This paper introduces the basic theory of adsorption cycle as well as the advanced adsorption cycles such as heat and mass recovery cycle, thermal wave cycle and convection thermal wave cycle. The types, characteristics, advantages and drawbacks of different adsorbents used in adsorption refrigeration systems are also summarized. This article will increase the awareness of this emerging cooling technology among the HVAC engineers and help them select appropriate adsorption systems in energy-efficient building design.

  20. Modeling of secondary loop refrigeration systems in supermarket applications

    Microsoft Academic Search

    William Travis Horton

    2002-01-01

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

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

    Microsoft Academic Search

    Alston

    1993-01-01

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

  2. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...refrigeration system must: (1) Have a heat exchanger with an excess capacity...required capacity; or (2) A standby heat exchanger. (d) Where cooling...other. (f) The pressure of the heat transfer fluid in each cooling coil in a...

  3. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...refrigeration system must: (1) Have a heat exchanger with an excess capacity...required capacity; or (2) A standby heat exchanger. (d) Where cooling...other. (f) The pressure of the heat transfer fluid in each cooling coil in a...

  4. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...refrigeration system must: (1) Have a heat exchanger with an excess capacity...required capacity; or (2) A standby heat exchanger. (d) Where cooling...other. (f) The pressure of the heat transfer fluid in each cooling coil in a...

  5. A high-efficiency traveling-wave thermoacoustic refrigerator for cryogenic cooling operation: thermodynamic design and prelimnianry experiment

    NASA Astrophysics Data System (ADS)

    Ren, Jia; Luo, Ercang; Zhang, Liming; Hu, Jianying; Dai, Wei

    2012-06-01

    This paper theoretically studied a traveling-wave thermoacoustic cryocooler (TWTAC), simultaneously comparing with an inertance-tube pulse tube cryocooler operating in liquid nitrogen temperature range. The same core thermodynamic components are fixed and used in the both cryocoolers. First, thermodynamic design and optimization mainly on their phase shifting devices are made. For 77 K operation, the theoretical results show that the TWTAC has an increase of efficiency by about 10% compared with the inertance pulse tube cryocooler. Then, preliminary experiments on the TWTAC driven by a linear compressor were conducted. So far, the traveling-wave thermoacoustic cryocooler has achieved a no-load refrigeration temperature of 135 K with a pressure ratio of 1.15, and the reasons for huge different between the theoretical and experimental results are being indentified.

  6. A New Surface Tension Equation for Refrigerants

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  7. Refrigerant charge management in a heat pump water heater

    DOEpatents

    Chen, Jie; Hampton, Justin W.

    2014-06-24

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

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

    SciTech Connect

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

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

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

    SciTech Connect

    Not Available

    1992-10-01

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

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

    SciTech Connect

    NONE

    1993-08-01

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

  11. Thermoelectric refrigerator having improved temperature stabilization means

    DOEpatents

    Falco, Charles M. (Woodridge, IL)

    1982-01-01

    A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized.

  12. Cryogenic refrigeration apparatus

    DOEpatents

    Crunkleton, James A. (Cambridge, MA)

    1992-01-01

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

  13. Thermoacoustic refrigeration

    NASA Technical Reports Server (NTRS)

    Garrett, Steven L.; Hofler, Thomas J.

    1991-01-01

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

  14. Microcomputer Software for Refrigerant Property and Cycle Analysis Calculations

    E-print Network

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

    the properties of temperature, pressure, enthalpy, entropy, and specific volume at all state points in a refrigeration cycle for any of the 11 refrigerants. In addition, RBPRIG computes coefficients of performance for both the refrigeration and the heat pump.... This approximation is used in determining sub cooled specific volume, internal energy, and entropy. Sub-cooled enthalpy is corrected for the increase in pressure above saturation by the following: Refrigeration Cycle Analysis In addition to the property determi...

  15. Atomic-Scale Thermoelectric Refrigerator

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chang; Liu, Yu-Shen

    2010-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    Dynamic light scattering (DLS) has been used for the measurement of several thermophysical properties of the refrigerant mixtures R417A (50 % by mass 1,1,1,2-tetrafluoroethaneR134a, 46.6 % pentafluoroethaneR125, 3.4 % n-butaneR600) and R417B (79 % by mass R125, 18.25 % R134a, 2.75 % R600). Both refrigerant mixtures are designed for a replacement of R22 (chlorodifluoromethane) in existing refrigeration systems. Thermal diffusivity and sound speed have been obtained by light scattering from the bulk fluid for the liquid phase under saturation conditions over a temperature range from about 283 K up to the liquid-vapor critical point with estimated uncertainties between 1 % and 3 % and between 0.5 % and 2 %, respectively. By applying the method of DLS to a liquid-vapor interface, also called surface light scattering, the saturated liquid kinematic viscosity and surface tension have been determined simultaneously. These properties have been measured from 253.15 K up to the liquid-vapor critical point with estimated uncertainties between 1 % and 3 % for kinematic viscosity and between 1 % and 2 % for surface tension. The measured thermal diffusivity, sound speed, kinematic viscosity, and surface tension are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with but always smaller than the uncertainties. The results are discussed in detail in comparison with literature data and with various prediction methods.

  17. Thermoelectric refrigerator for gas analyzer

    Microsoft Academic Search

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

    1987-01-01

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

  18. Short-Cycle Adsorption Refrigerator

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1988-01-01

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

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

    E-print Network

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

    1996-01-01

    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...

  20. Superfluid thermodynamic cycle refrigerator

    DOEpatents

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

    1992-12-22

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

  1. Oxygen chemisorption cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (inventor)

    1987-01-01

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

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

    SciTech Connect

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

    2008-04-15

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

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

    PubMed

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

    2012-12-01

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

  4. Experimental evaluation of prototype thermoelectric domestic-refrigerators

    Microsoft Academic Search

    Gao Min; D. M. Rowe

    2006-01-01

    A number of prototype thermoelectric refrigerators are investigated and their cooling performances evaluated in terms of the coefficient-of-performance, heat-pumping capacity and cooling-down rate. The coefficient-of-performance of a thermoelectric refrigerator is found to be around 0.30.5 for a typical operating temperature at 5C with ambient at 25C. The potential improvement in the cooling performance of a thermoelectric refrigerator is also investigated

  5. Solar energy refrigeration and air conditioning system

    Microsoft Academic Search

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

    1977-01-01

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

  6. Experimental investigation of mass recovery adsorption refrigeration cycle

    Microsoft Academic Search

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

    2005-01-01

    The study investigates the performance of silica gelwater adsorption refrigeration cycle with mass recovery process by experimental prototype machine. In an adsorption refrigeration cycle, the pressures in adsorber and desorber are different. The mass recovery cycle utilizes the pressure difference to enhance the refrigerant mass circulation. Moreover, novel cycle was proposed for improvement of cooling output. In our previous study,

  7. Subterranean heat exchanger for refrigeration air conditioning equipment

    Microsoft Academic Search

    Rothwell

    1980-01-01

    Heat exchanger apparatus for use with refrigeration cycle heating and cooling equipment is disclosed. In the preferred embodiment, it cooperates with and modifies refrigeration equipment including a compressor, an expansion valve, an evaporator coil and a closed loop for cycling refrigerant. This apparatus is a sealed container adapted to be placed in a well extending into artesian (Relatively heated or

  8. Intra-molecular refrigeration in enzymes

    E-print Network

    Hans J. Briegel; Sandu Popescu

    2009-12-14

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

  9. Thermal modeling for an optical refrigerator

    NASA Astrophysics Data System (ADS)

    Martin, K. W.; Schomacker, J.; Fraser, T.; Dodson, C.

    2015-03-01

    Optical refrigeration is currently the only completely solid state cooling method capable of reaching cryogenic temperatures from room temperature. Optical cooling utilizing Yb:YLF as the refrigerant crystal has resulted in temperatures lower than 123K measured via a fluorescence thermometry technique. However, to be useful as a refrigerator this cooling crystal must be attached to a sensor or other payload. The phenomenology behind laser cooling, known as anti-Stokes fluorescence, has a relatively low efficiency which makes the system level optimization and limitation of parasitic losses imperative. We propose a variety of potential designs for a final optical refrigerator, enclosure and thermal link; calculate conductive and radiative losses, and estimate direct fluorescence reabsorption. Our simulated designs show losses between 60 and 255 mW, depending on geometry and enclosure choice, with a lower bound as low as 23 mW.

  10. Control system for thermoelectric refrigerator

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  11. Refrigeration system for W7-X

    Microsoft Academic Search

    Y. Bozhko; F. Schauer

    2003-01-01

    The refrigeration system for the W7-X superconducting magnet and the divertor cryo-vacuum pumps is presented. In total, five main helium cooling circuits have to be supplied by the refrigerator---four for the magnet including auxiliary equipment like support structure, thermal shield and current leads, and one for the cryo-pumps. For the shields of the latter, an additional LN2---cooling circuit is required.

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

    SciTech Connect

    Calm, J.M.

    1993-11-28

    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.

  13. Thermoelectric refrigerator

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  14. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A. (Los Alamos, NM)

    1992-01-01

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

  15. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

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

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

    SciTech Connect

    Rudick, A.G.

    1988-04-19

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

  17. A rocket-borne He-3 refrigerator

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

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

    PubMed

    Levine, C; Younglove, T; Barth, M

    2000-10-01

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

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

    Microsoft Academic Search

    R. L. Webb; Shinobu Yamauchi; Showa Denko

    2002-01-01

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

  20. A recuperative superfluid stirling refrigerator

    SciTech Connect

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

    1993-07-01

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

  1. A recuperative superfluid stirling refrigerator

    SciTech Connect

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

    1994-12-31

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

  2. Refrigeration Showcases

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Through the Technology Affiliates Program at the Jet Propulsion Laboratory (JPL), valuable modifications were made to refrigerator displays built by Displaymor Manufacturing Company, Inc. By working with JPL, Displaymor could address stiffer requirements that ensure the freshness of foods. The application of the space technology meant that the small business would be able to continue to market its cases without incurring expenses that could threaten the viability of the business, and the future of several dozen jobs. Research and development improvements in air flow distribution and refrigeration coil technology contributed greatly to certifying Displaymor's showcases given the new federal regulations. These modifications resulted in a refrigerator case that will keep foods cooler, longer. Such changes maintained the openness of the display, critical to customer visibility and accessibility, impulse buying, and cross-merchandising.

  3. The Quantum Absorption Refrigerator

    E-print Network

    Amikam Levy; Ronnie Kosloff

    2011-11-09

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

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

    NASA Technical Reports Server (NTRS)

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

    1956-01-01

    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.

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

    SciTech Connect

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

    1996-02-01

    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.

  6. Some problems in the development of a commercial thermoelectric refrigerator

    Microsoft Academic Search

    T B Burnett; H O Lorch; J E Thompson

    1961-01-01

    Two basic problems in the development of a thermoelectric refrigerator are the construction of a cooling unit, consisting of the thermoelectric junctions, and the optimization of the complete refrigerator design to make best use of the thermoelectric material. It is essential for the unit to achieve good thermal contact with the cooling chamber and to have good electrical contact across

  7. Performance optimization analysis of a thermoelectric refrigerator with two resonances

    Microsoft Academic Search

    Xiao-Guang Luo; Ji-Zhou He

    2011-01-01

    Based on electron transport theory, the performance of kx and kr filtered thermoelectric refrigerators with two resonances are studied in this paper. The performance characteristic curves between the cooling rate and the coefficient of performance are plotted by numerical calculation. It is shown that the maximum cooling rate of the thermoelectric refrigerator with two resonances increases but the maximum coefficient

  8. Performance Evaluation of a 4.5 kW (1.3 Refrigeration Tons) Air-Cooled Lithium Bromide/Water Solar Powered (Hot-Water-Fired) Absorption Unit

    SciTech Connect

    Zaltash, Abdolreza [ORNL; Petrov, Andrei Y [ORNL; Linkous, Randall Lee [ORNL; Vineyard, Edward Allan [ORNL

    2007-01-01

    During the summer months, air-conditioning (cooling) is the single largest use of electricity in both residential and commercial buildings with the major impact on peak electric demand. Improved air-conditioning technology has by far the greatest potential impact on the electric industry compared to any other technology that uses electricity. Thermally activated absorption air-conditioning (absorption chillers) can provide overall peak load reduction and electric grid relief for summer peak demand. This innovative absorption technology is based on integrated rotating heat exchangers to enhance heat and mass transfer resulting in a potential reduction of size, cost, and weight of the "next generation" absorption units. Rotartica Absorption Chiller (RAC) is a 4.5 kW (1.3 refrigeration tons or RT) air-cooled lithium bromide (LiBr)/water unit powered by hot water generated using the solar energy and/or waste heat. Typically LiBr/water absorption chillers are water-cooled units which use a cooling tower to reject heat. Cooling towers require a large amount of space, increase start-up and maintenance costs. However, RAC is an air-cooled absorption chiller (no cooling tower). The purpose of this evaluation is to verify RAC performance by comparing the Coefficient of Performance (COP or ratio of cooling capacity to energy input) and the cooling capacity results with those of the manufacturer. The performance of the RAC was tested at Oak Ridge National Laboratory (ORNL) in a controlled environment at various hot and chilled water flow rates, air handler flow rates, and ambient temperatures. Temperature probes, mass flow meters, rotational speed measuring device, pressure transducers, and a web camera mounted inside the unit were used to monitor the RAC via a web control-based data acquisition system using Automated Logic Controller (ALC). Results showed a COP and cooling capacity of approximately 0.58 and 3.7 kW respectively at 35 C (95 F) design condition for ambient temperature with 40 C (104 F) cooling water temperature. This is in close agreement with the manufacturer data of 0.60 for COP and 3.9 kW for cooling capacity. This study resulted in a complete performance map of RAC which will be used to evaluate the potential benefits of rotating heat exchangers in making the "next-generation" absorption chillers more compact and cost effective without any significant degradation in the performance. In addition, the feasibility of using rotating heat exchangers in other applications will be evaluated.

  9. Enclosure for thermoelectric refrigerator and method

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  10. Solar-powered cooling system

    DOEpatents

    Farmer, Joseph C

    2013-12-24

    A solar-powered adsorption-desorption refrigeration and air conditioning system uses nanostructural materials made of high specific surface area adsorption aerogel as the adsorptive media. Refrigerant molecules are adsorbed on the high surface area of the nanostructural material. A circulation system circulates refrigerant from the nanostructural material to a cooling unit.

  11. Thermoacoustic Refrigerators Stack Optimization

    Microsoft Academic Search

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

    2010-01-01

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

  12. A Analysis of Magnetic Refrigeration and Refrigerants

    Microsoft Academic Search

    Michael Elra Wood

    1988-01-01

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

  13. Thermoacoustic Refrigerator's Stack Optimization

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  14. Wheel-type magnetic refrigerator

    DOEpatents

    Barclay, J.A.

    1983-10-11

    The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load. 7 figs.

  15. 24 CFR 3280.714 - Appliances, cooling.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances...refrigerating systems serving any air conditioning or comfort- cooling system...home shall employ a type of refrigerant that ranks no lower than...

  16. 24 CFR 3280.714 - Appliances, cooling.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances...refrigerating systems serving any air conditioning or comfort-cooling system...home shall employ a type of refrigerant that ranks no lower than...

  17. 24 CFR 3280.714 - Appliances, cooling.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances...refrigerating systems serving any air conditioning or comfort-cooling system...home shall employ a type of refrigerant that ranks no lower than...

  18. Thermoelectric refrigerator having improved temperature-stabilization means

    SciTech Connect

    Falco, C.M.

    1981-07-29

    A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized.

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

    NASA Astrophysics Data System (ADS)

    Field, J. E.

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

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

    SciTech Connect

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

    1994-04-01

    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.

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

    Microsoft Academic Search

    V. C. Mei; F. C. Chen

    1997-01-01

    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

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

    Microsoft Academic Search

    Viung C. Mei; Fang C. Chen

    1997-01-01

    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

  3. Measurements with a recuperative superfluid Stirling refrigerator

    SciTech Connect

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

    1995-08-01

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

  4. Measurements with a recuperative superfluid stirling refrigerator

    SciTech Connect

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

    1996-12-31

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

  5. Ground Loops for Heat Pumps and Refrigeration

    E-print Network

    Braud, H. J.

    1986-01-01

    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...

  6. New Energy-Saving Cooling System

    Microsoft Academic Search

    I. Fukuchi; K. Kobayashi; H. Yamamoto

    1982-01-01

    This paper describes an energy-saving cooling system for the cooling of computer rooms that does not require the operation of existing cooling systems but carries out cooling utilizing the cold outdoor air of the winter season. Instead of using conventional refrigerants as the cooling medium, the new cooling system utilizes cold water. Water cooled by the low temperature outdoor air

  7. Cryogen-free dilution refrigerators

    NASA Astrophysics Data System (ADS)

    Uhlig, K.

    2012-12-01

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

  8. Optimizing Cooling Tower Performance Refrigeration Systems, Chemical Plants, and Power Plants All Have A Resource Quietly Awaiting Exploitation-Cold Water!!

    E-print Network

    Burger, R.

    1991-01-01

    OPTIMIZING COOLING TOWER PERFOnMANCE REFnIGERATION SYSTEMS, CHEMICAL PLANTS, AND POWER PLANTS ALL HAVE A RESOURCE QUIETLY AWAITING EXPLOITATION - COLD WATER!! ROBERT BURGER President Burger and Associates. Inc Dallas, Texas Cooling towers... 62 OPTIMIZING COOLING TOWER PERFOflMANCE REFflIGERATION SYSTEMS, CHEMICAL PLANTS, AND POWER PLANTS ALL HAVE A flESOURCE QUIETLY AWAITING EXPLOITATION COLD WATER!! ROBERT BURGER President Burger and Associates. DaBas, Texas Inc pretty well convinced...

  9. Three-terminal quantum-dot refrigerators

    NASA Astrophysics Data System (ADS)

    Zhang, Yanchao; Lin, Guoxing; Chen, Jincan

    2015-05-01

    Based on two capacitively coupled quantum dots in the Coulomb-blockade regime, a model of three-terminal quantum-dot refrigerators is proposed. With the help of the master equation, the transport properties of steady-state charge current and energy flow between two quantum dots and thermal reservoirs are revealed. It is expounded that such a structure can be used to construct a refrigerator by controlling the voltage bias and temperature ratio. The thermodynamic performance characteristics of the refrigerator are analyzed, including the cooling power, coefficient of performance (COP), maximum cooling power, and maximum COP. Moreover, the optimal regions of main performance parameters are determined. The influence of dissipative tunnel processes on the optimal performance is discussed in detail. Finally, the performance characteristics of the refrigerators operated in two different cases are compared.

  10. Room Temperature Magnetic Refrigerator Using Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Naoki, Hirano

    2003-03-01

    This paper describes experimental results of a magnetic refrigerator which is operated at room temperature region. The feature of this study is that a permanent magnet is used to make a magnetic field. A magnetic refrigerator has been expected as an Eco-friendly refrigerator which does not use any CFCs (chlorofluorocarbons) or alternatives and as a high efficient refrigerator. But one of the technical issues for a magnetic refrigerator is that it needs a high magnetic field. A superconducting magnet has been often used to generate a high magnetic field up to about 5 T. It reduces a efficiency and increases the size of a magnetic refrigerator. In this study, a permanent magnet was adopted to generate a magnetic field of 0.6 T and confirmed the refrigeration at room temperature region with such a weak magnetic field. The magnetic refrigerator mainly consisted of two sets of FeNdB magnet with iron yokes, four sets of magnetic material vessels with driving system and cooling system of materials. Gd_1-XDyX were used as magnetic materials and they were filled in magnetic material vessels. Three kinds of materials such as Gd_1-XDyX (x = 0.11, 0.13, 0.16) were used and their Curie temperatures were 10 ^oC, 5 ^oC and 0 ^oC respectively. The magnetic material vessels were reciprocated by the driving system to apply high (0.6 T) and low (0 T) magnetic field to the materials alternatively. Each vessel had two pipes which were connected to the cooling system. The cooling system flowed alcohol doped water alternatively. The alternative magnetic field and water flow in 0.25 Hz made an active magnetic refrigeration cycle. In this configuration, the maximum temperature difference of 12 ^oC was obtained and the lowest temperature of -1 ^oC was achieved.

  11. Optical refrigeration with coupled quantum wells

    E-print Network

    R. S. Daveau; P. Tighineanu; P. Lodahl; S. Stobbe

    2015-06-23

    Refrigeration of a solid-state system with light has potential applications for cooling small-scale electronics and photonics. We show theoretically that two coupled semiconductor quantum wells are efficient cooling media for optical refrigeration because they support long-lived indirect electron-hole pairs. Thermal excitation of these pairs to distinct higher-energy states with faster radiative recombination allows an efficient escape channel to remove thermal energy from the system. From band-diagram calculations along with an experimentally realistic level scheme we calculate the cooling efficiency and cooling yield of different devices with coupled quantum wells embedded in a suspended membrane. The dimension and composition of the quantum wells allow optimizing either of these quantities, which cannot, however, be maximized simultaneously. Quantum-well structures with electrical control allow tunability of carrier lifetimes and energy levels so that the cooling efficiency can be optimized over time as the thermal population decreases due to the cooling.

  12. Low Noise CCD System Design and Implementation Based on Thermoelectric Refrigerating Unit

    Microsoft Academic Search

    Zheng Dezhi; Gong Jingjie; Song Xinbo; Guan Ming

    2010-01-01

    By the research on the characteristics of CCD temperature - noise, this paper designs a cooling CCD which uses a miniaturized refrigeration technique in order to meet the request of obtaining high-quality image in the dim light conditions. The design uses thermoelectric cooling technology and accomplishes the cooling design and optimization of refrigeration cavity with the assistance of Qfin. The

  13. Conversion of liquid-nitrogen traps to mechanical refrigeration

    NASA Astrophysics Data System (ADS)

    Coggiola, M. J.; Leon, R. L.; Scally, R. L.

    1983-07-01

    A simple technique is described which allows a reservoir-type liquid-nitrogen trap to be converted to continuous operation with a closed-cycle mechanical refrigeration system. The conversion requires no internal modification to the trap and uses only standard commercial refrigeration components. Using 502 refrigerant as the working fluid, temperatures of -52 C are readily achieved in a trap operating above a 6-in. water-cooled baffle and oil diffusion pump.

  14. ARTI refrigerant database

    SciTech Connect

    Calm, J.M.

    1996-07-01

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

  15. ARTI refrigerant database

    SciTech Connect

    Calm, J.M.

    1996-11-15

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

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

    Microsoft Academic Search

    Michael P. Susalla

    1988-01-01

    The objective of the STAR project is to test and space-qualify a new continuous cycle cryogenic refrigeration system for cooling of sensors and electronics which is based on the newly discovered thermoacoustic heat pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 Hz, and uses acoustic resonance to enhance the overall power density and

  17. Electrodynamic driver for the space thermoacoustic refrigerator (STAR)

    Microsoft Academic Search

    Michele Fitzpatrick

    1988-01-01

    The objective of the STAR project is to test and space qualify a new continuous cycle cryogenic refrigeration system for cooling of sensors and electronics which is based upon the newly discovered thermoacoustic heat pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 hz, and uses acoustic resonance to enhance the overall power density

  18. Finite time thermoeconomic optimization for endoreversible refrigerators and heat pumps

    Microsoft Academic Search

    Bahri Sahin; Ali Kodal

    1999-01-01

    This paper reports a new kind of finite time thermoeconomic optimization for an endoreversible refrigerator and a heat pump. The cooling load for the refrigerator and the heating load for the heat pump per unit total cost are proposed as objective functions for the optimization. The optimum performance parameters which maximize the objective functions are investigated. Since the optimization technique

  19. Development of a solar-powered passive ejector cooling system

    Microsoft Academic Search

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

    2001-01-01

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

  20. Influence of irreversible losses on the performance of a two-stage magnetic Brayton refrigeration cycle

    Microsoft Academic Search

    X. Zhang; J. Chen; G. Lin; E. Brck

    2010-01-01

    The general performance characteristics of a two-stage magnetic Brayton refrigeration cycle consisting of three constant magnetic fields and three irreversible adiabatic processes are investigated. Based on the thermodynamic properties of a magnetic material and the irreversible cycle model of a two-stage Brayton refrigerator, expressions for the cooling load and coefficient of performance of the refrigeration system are derived. The influence

  1. Development test on 2 K cooling systems

    Microsoft Academic Search

    Toshiaki Okudaira; Genshirou Fujii

    1993-01-01

    Topics discussed include: the detail of proposal; configuration of the laboratory dilution refrigerator; the adiabatic vacuum section of the dilution refrigerator; the relationship between refrigerating capability and cooling temperature; phase diagram and vapor pressure curves of the He-3 and He-4; the fractionation chamber and dilution chamber; separation control by electric field of He-3 rich and He-4 rich phases; mixer utilizing

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

    NASA Astrophysics Data System (ADS)

    Ki, Taekyung; Jeong, Sangkwon

    2011-06-01

    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.

  3. Applications Tests of Energy Efficient, Environmentally Friendly Refrigerants

    E-print Network

    Nimitz, J.; Glass, S.; McCullough, E.; Dhooge, P.

    1999-01-01

    common refrigeration system materials of construction. This paper presents (1) results of performance demonstration of Ikon B in an instrumented spare of the Space Shuttle Cabin cooling system at NASA KSC; (2) results from performance demonstration...

  4. Applications Tests of Energy Efficient, Environmentally Friendly Refrigerants

    E-print Network

    Nimitz, J.; Glass, S.; McCullough, E.; Dhooge, P.

    common refrigeration system materials of construction. This paper presents (1) results of performance demonstration of Ikon B in an instrumented spare of the Space Shuttle Cabin cooling system at NASA KSC; (2) results from performance demonstration...

  5. Refrigerating machine oil

    SciTech Connect

    Nozawa, K.

    1981-03-17

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

  6. Optimization of Industrial Refrigeration Plants: Including a Case Study at Stonyfield Farm Yogurt

    E-print Network

    Dixon, R.; McCowan, B.; Drake, L.; Epstein, G.; D'Antonio, M.; Moray, S.

    2006-01-01

    hybrid DX and liquid overfeed ammonia refrigeration system. Figure 2: Typical Hybrid DX and Liquid Overfeed Ammonia Refrigeration System 45-50 F Cooling Loads High Pressure Receiver (Liquid) 135-165 psia Liquid Ammonia (NH3) Gas Liquid +Gas Thermal.... The first is the high-pressure receiver where liquid refrigerant exiting the condenser is stored. Liquid refrigerant from the high-pressure receiver is then throttled either to the intermediate pressure receiver or to the direct expansion evaporators...

  7. Superconducting tunnel-junction refrigerator

    SciTech Connect

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

    1980-03-01

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

  8. Optimal performance of endoreversible quantum refrigerators.

    PubMed

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

    2014-12-01

    The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results that are model independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for any endoreversible quantum refrigerator. At striking variance with the universality of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics. PMID:25615061

  9. Optimal performance of endoreversible quantum refrigerators

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  10. Acoustic recovery of lost power in pulse tube refrigerators

    SciTech Connect

    Swift, G.W.; Gardner, D.L.; Backhaus, S. [Condensed Matter and Thermal Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Condensed Matter and Thermal Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1999-02-01

    In an efficient Stirling-cycle cryocooler, the cold piston or displacer recovers power from the gas. This power is dissipated into heat in the orifice of an orifice pulse tube refrigerator, decreasing system efficiency. Recovery of some of this power in a pulse tube refrigerator, without sacrificing the simplicity and reliability inherent in a system with no cold moving parts, is described in this paper. In one method of such power recovery, the hot ends of both the regenerator and the pulse tube are connected to the front of the piston driving the refrigerator. Experimental data is presented demonstrating this method using a thermoacoustic driver instead of a piston driver. Control of time-averaged mass flux through the refrigerator is crucial to this power recovery, lest the refrigerator{close_quote}s cooling power be overwhelmed by a room-temperature mass flux. Two methods are demonstrated for control of mass flux: a barrier method, and a hydrodynamic method based on turbulent irreversible flow. At {minus}55{degree}C, the refrigerator provided cooling with 9{percent} of the Carnot coefficient of performance. With straightforward improvements, similar refrigerators should achieve efficiencies greater than those of prior pulse tube refrigerators and prior standing-wave thermoacoustic refrigerators, while maintaining the advantages of no moving parts. {copyright} {ital 1999 Acoustical Society of America.}

  11. ARTI Refrigerant Database

    SciTech Connect

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

    1994-05-27

    The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

  12. Optimal performance of a thermoelectric refrigerator

    Microsoft Academic Search

    Goektun

    1996-01-01

    By employing an externally and internally irreversible Carnot-like reversed heat engine model, the coefficient of performance and maximum cooling rate have been determined for a thermoelectric refrigerator. The irreversibilities can be characterized by a single parameter called the device-design parameter. The coefficient of performance and the cooling rate increase with an increase of the device-design parameter, which appears in the

  13. Optimal Performance of a Thermoelectric Refrigerator

    Microsoft Academic Search

    SELAHATT?N GKTUN

    1996-01-01

    By employing an externally and internally irreversible Carnot-like reversed heat engine model, the coefficient of performance and maximum cooling rate have been determined for a thermoelectric refrigerator. The irreversibilities can be characterized by a single parameter called the device-design parameter. The coefficient of performance and the cooling rate increase with an increase of the device-design parameter, which appears in the

  14. Stirling-Cycle Refrigerator Containing Piezoelectric Pumps

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr.; Hellbaum, R. F.

    1995-01-01

    Advanced Stirling-cycle cryogenic apparatus suitable for cooling sensitive infrared detectors to very low temperatures. Working fluid in refrigerator helium. Working fluid compressed and circulated by three piezoelectrically actuated diaphragm pumps offering advantages of greater reliability, relative simplicity, and lower cost.

  15. Optimal Pellet Geometries for Thermoelectric Refrigeration

    Microsoft Academic Search

    Marc Hodes

    2007-01-01

    For a thermoelectric module (TEM) operating in refrigeration mode, the cooling flux provided by it, its coefficient of performance and its operating voltage per unit footprint are key parameters. They are provided here as a function of the temperatures on both sides of a TEM, current flow through it, electrical contact resistance at its interconnects and the geometry, material properties

  16. VLHC Thermal Shield Cooling

    Microsoft Academic Search

    C. Darve; P. Bauer; T. Nicol; T. Peterson

    The Very Large Hadron Collider (VLHC) - stage 2 cooling system has been optimized regarding the ability to minimize the total refrigeration power. The stage 2 VLHC synchrotron radiation dictates a high optimal beam screen temperature. LHC dipole cryostat thermal model results provide data to characterize the behavior of the stage 2 VLHC cooling system. In the cryogenic concept pursued

  17. Cooling Towers--Energy Conservation Strategies

    E-print Network

    Matson, J.

    A cooling water system can be optimized by operating the cooling tower at the highest possible cycles of concentration without risking sealing and fouling of heat exchanger surfaces, tube bundles, refrigeration equipment, overhead condensers...

  18. Optimize refrigeration design

    Microsoft Academic Search

    Baggio

    1984-01-01

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

  19. Thermoacoustic Refrigerator's Stack Optimization

    Microsoft Academic Search

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

    2010-01-01

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

  20. Japanese refrigerators field testing

    Microsoft Academic Search

    1989-01-01

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

  1. Japanese Refrigerators Field Testing

    Microsoft Academic Search

    Albert T

    1989-01-01

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

  2. Solar Powered Refrigeration System

    Microsoft Academic Search

    Michael K. Ewert; David J. Bergeron III

    2002-01-01

    A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant

  3. Improving the Efficiency of Your Process Cooling System

    E-print Network

    Baker, R.

    2005-01-01

    Many industries require process cooling to achieve desired outcomes of specific processes. This cooling may come from cooling towers, once-through water, mechanical refrigeration, or cryogenic sources such as liquid nitrogen or dry ice. This paper...

  4. A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus

    SciTech Connect

    Raustad, Richard A. [Florida Solar Energy Center

    2013-01-01

    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.

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

    Microsoft Academic Search

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

    2011-01-01

    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

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

    Microsoft Academic Search

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

    2012-01-01

    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

  7. Study on adsorption refrigeration cycle utilizing activated carbon fibers. Part 1. Adsorption characteristics

    Microsoft Academic Search

    Y. Hamamoto; K. C. A. Alam; B. B. Saha; S. Koyama; A. Akisawa; T. Kashiwagi

    2006-01-01

    Thermal heat driven adsorption systems using natural refrigerants have been focused on the recent energy utilization trend. However, the drawbacks of these adsorption systems are their poor performance in terms of system cooling capacity and coefficient of performance (COP). The objective of this paper is to improve the performance of thermally powered adsorption cooling system by selecting new adsorbentrefrigerant pair.

  8. Refrigeration system for W7-X

    NASA Astrophysics Data System (ADS)

    Bozhko, Y.; Schauer, F.

    2003-09-01

    The refrigeration system for the W7-X superconducting magnet and the divertor cryo-vacuum pumps is presented. In total, five main helium cooling circuits have to be supplied by the refrigeratorfour 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 LN2cooling 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 boxwhich is installed for W7-X cool-down anywaycan 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.

  9. Superfluid Stirling refrigerator with a counterflow regenerator

    SciTech Connect

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

    1992-01-01

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

  10. Novel materials for laser refrigeration

    SciTech Connect

    Hehlen, Markus P [Los Alamos National Laboratory

    2009-01-01

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

  11. Quantum Heat Engines and Refrigerators: Continuous Devices

    NASA Astrophysics Data System (ADS)

    Kosloff, Ronnie; Levy, Amikam

    2014-04-01

    Quantum thermodynamics supplies a consistent description of quantum heat engines and refrigerators up to a single few-level system coupled to the environment. Once the environment is split into three (a hot, cold, and work reservoir), a heat engine can operate. The device converts the positive gain into power, with the gain obtained from population inversion between the components of the device. Reversing the operation transforms the device into a quantum refrigerator. The quantum tricycle, a device connected by three external leads to three heat reservoirs, is used as a template for engines and refrigerators. The equation of motion for the heat currents and power can be derived from first principles. Only a global description of the coupling of the device to the reservoirs is consistent with the first and second laws of thermodynamics. Optimization of the devices leads to a balanced set of parameters in which the couplings to the three reservoirs are of the same order and the external driving field is in resonance. When analyzing refrigerators, one needs to devote special attention to a dynamical version of the third law of thermodynamics. Bounds on the rate of cooling when Tc?0 are obtained by optimizing the cooling current. All refrigerators as Tc?0 show universal behavior. The dynamical version of the third law imposes restrictions on the scaling as Tc?0 of the relaxation rate γc and heat capacity cV of the cold bath.

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

    SciTech Connect

    Leigh, R.; Andrews, J.

    1995-11-01

    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.

  13. Performance of an irreversible quantum refrigeration cycle

    NASA Astrophysics Data System (ADS)

    He, Ji-Zhou; Ouyang, Wei-Pin; Wu, Xin

    2006-01-01

    A new model of a quantum refrigeration cycle composed of two adiabatic and two isomagnetic field processes is established. The working substance in the cycle consists of many non-interacting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semi-group approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate and power input, are given. It is found that the coefficient of performance of this cycle is in the closest analogy to that of the classical Carnot cycle. Furthermore, at high temperatures the optimal relations of the cooling rate and the maximum cooling rate are analysed in detail. Some performance characteristic curves of the cycle are plotted, such as the cooling rate versus the maximum ratio between high and low ``temperatures'' of the working substances, the maximum cooling rate versus the ratio between high and low ``magnetic fields'' and the ``temperature'' ratio between high and low reservoirs. The obtained results are further generalized and discussed, so that they may be directly applied to describing the performance of the quantum refrigerator using spin-J systems as the working substance. Finally, the optimum characteristics of the quantum Carnot and Ericsson refrigeration cycles are derived by analogy.

  14. New Design of Neon Refrigerator for Hts Power Machines

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    In 2007, we developed a prototype refrigerator with a small turbo-expander to provide adequate cooling power (2 kW at 70 K) for HTS (High Temperature Superconductor) power machines. The reverse-Brayton cycle with neon gas as a working fluid was adopted in the refrigerator. The prototype refrigerator does not have enough COP (Coefficient of Performance) for practical HTS applications, and the purpose of this study is to research the information required for designing a new neon refrigerator with improved performance. We take the same refrigeration cycle and working fluid as the prototype one adopted, but a lower process pressure of 1 MPa/0.5 MPa is chosen instead of 2 MPa/1 MPa. The lower process pressure is required by the turbo-compressor design and the refrigeration process is analyzed by using a newly developed process simulator. Also, a heat-exchanger configuration is studied to make the refrigerator size small. The new refrigerator will have a cooling power of 2.5 kW at 65 K, and a COP of 0.06 at 80 K.

  15. Room-temperature semiconductor heterostructure refrigeration

    NASA Astrophysics Data System (ADS)

    Chao, K. A.; Larsson, Magnus; Mal'shukov, A. G.

    2005-07-01

    With the proper design of semiconductor tunneling barrier structures, we can inject low-energy electrons via resonant tunneling, and take out high-energy electrons via a thermionic process. This is the operation principle of our semiconductor heterostructure refrigerator (SHR) without the need of applying a temperature gradient across the device. Even for the bad thermoelectric material AlGaAs, our calculation shows that at room temperature, the SHR can easily lower the temperature by 5-7K. Such devices can be fabricated with the present semiconductor technology. Besides its use as a kitchen refrigerator, the SHR can efficiently cool microelectronic devices.

  16. The application of Stirling cooler to refrigeration

    SciTech Connect

    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

    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.

  17. Experimental measurement on characteristics of cool storage air conditioning system

    Microsoft Academic Search

    Guiyin Fang; Fan Yang; Man Zhang; Shuangmao Wu

    2008-01-01

    The experimental apparatus of cool storage air conditioning system is designed and constructed. The characteristics of cool storage air-conditioning system are experimentally measured. The temperature variation of coolant in the evaporator is presented by experiments. The refrigerant temperature in the evaporator and the compressor discharge temperature are also shown. The cool storage experiments are carried out to measure the refrigeration

  18. Supermarket with Ground Coupled Carbon Dioxide Refrigeration Plant

    E-print Network

    Rehault, N.

    2012-01-01

    Warming Potential = 1 (R404A GWP=3700) ? Ozone Depletion Potential = 0 ? Non-inflammable, nontoxic ? High volumetric heat capacity ? Higher efficiency in comparison to plants running with R134a or R404 (at low condensation temperatures...

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

    SciTech Connect

    Not Available

    1994-08-01

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

  20. An experimental study of the flow boiling of refrigerant-based nanofluids

    NASA Astrophysics Data System (ADS)

    Kolekar, Rahul Dadasaheb

    The use of nanofluids for various heat transfer applications has been a topic of intense research over the last decade. A number of studies to evaluate the thermophysical properties and single-phase heat transfer behavior of nanofluids have been reported. The current study is focused on the use of nanofluids in flow boiling applications, with CO2 and R134a used as the base refrigerants. CuO nanoparticles 40nm in size, and TiO2 nanoparticles 200nm in size are used to create partially stable CO2-based nanofluids. Stable nanofluids are created in R134a by mixing it with dispersions of surface-treated nanoparticles in polyolester (POE) oil (RL22H and RL68H). The particles (Al 2O3, ZnO, CuO, and ATO) at particle mass fractions from 0.08% to 1.34%, with particle sizes of 20nm and 40nm are coated with polar and non-polar surface treatments. The thermal properties of R134a-based nanofluids are measured. Thermal conductivity shows limited improvements; the largest increase of 13% is observed with CuO nanoparticles. Significant increases in viscosity, as high as 2147%, are observed due to CuO nanoparticles. Only the ATO nanofluid exhibited a decrease in the measured viscosity. Heat transfer coefficients during flow boiling of nanofluids are measured over a range of mass flux from 100 to 1000 kg/m2s, with a heat flux from 5 to 25kW/m2, and vapor quality up to 1. The test section is a smooth copper tube, 6.23mm in diameter and 1.8m in length. Average decreases of 5% and 28% are observed in heat transfer coefficients during flow boiling of CuO/CO2 and TiO2/CO2 nanofluids, respectively. For the R134a-based nanofluids, average decreases in heat transfer during flow boiling at the highest particle mass fraction are 15% and 22% for Al2O3 and ZnO nanoparticles, respectively. CuO nanoparticles exhibit an average decrease of 7% for particle mass fraction of 0.08%. An average increase of 10% is observed with ATO nanoparticles at a 0.22% mass fraction. Heat transfer performance deteriorates with increase in viscosity and particle number density. The performance is also worse for partially stable nanofluids that modify the test section surface. Modifications to the thermophysical properties is the primary mechanism that affects heat transfer performance during flow boiling of nanofluids; increased thermal conductivity enhances while increased viscosity and surface tension reduce heat transfer in nucleate boiling-dominated flows. A secondary mechanism of nanoparticles filling up the micro-cavities on test surface is also responsible for decreased heat transfer and is a strong function of particle number density.

  1. An adiabatic demagnetization refrigerator for SIRTF

    SciTech Connect

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

    1989-02-01

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

  2. An adiabatic demagnetization refrigerator for SIRTF

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the multiband imaging photometer of the Space Infrared Telescope Facility (SIRTF). One such refrigerator has been built which uses a ferric ammonium alum salt pill suspended by nylon threads in a 3-T solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is less than 0.5 microW. The system has a hold time at 0.1K of more than 12 h. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built at a SIRTF prototype to fly on a ballon-borne telescope. It will use a ferromagnetic shield. The possibility of using a high-Tc solenoid-actuated heat switch is also discussed.

  3. Chemically assisted mechanical refrigeration process

    DOEpatents

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

    1987-01-01

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  4. Chemically assisted mechanical refrigeration process

    DOEpatents

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

    1987-01-01

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing he evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  5. Refrigerants in Transition

    E-print Network

    Stouppe, D. E.

    1991-01-01

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

  6. A tiltable single-shot miniature dilution refrigerator for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Melhuish, Simon J.; Martinis, Lorenzo; Piccirillo, Lucio

    2013-05-01

    We present a 3He/4He dilution refrigerator designed for cooling astronomical mm-wave telescope receivers to around 100 mK. Used in combination with a Gifford-McMahon closed-cycle refrigerator, 4He and 3He sorption-pumped refrigerators, our cryogen-free system is capable of achieving 2 ?W cooling power at 87 mK. A receiver attached directly to the telescope optics is required to rotate with respect to the downward direction. This scenario, of variable tilt, has proved difficult for typical dilution refrigerators, but our design has a geometry chosen to allow tilt to 45 and beyond.

  7. Application of Cryocoolers to a Vintage Dilution Refrigerator

    SciTech Connect

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

    2011-06-06

    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.

  8. Ecological optimization for an irreversible magnetic Ericsson refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Wu, Guo-Xing

    2013-08-01

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

  9. Influence of Oil on Refrigerant Evaporator Performance

    NASA Astrophysics Data System (ADS)

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

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

  10. Development and Comparison of Two Types of Cryogen-Free Dilution Refrigerator

    NASA Astrophysics Data System (ADS)

    Hata, T.; Matsumoto, T.; Obara, K.; Yano, H.; Ishikawa, O.; Handa, A.; Togitani, S.; Nishitani, T.

    2014-04-01

    Dilution refrigerators are an important tool used in solid state and quantum fluid physics for cooling to temperatures below 0.3 K. Conventional dilution refrigerators consume a lot of liquid helium, which has to be recharged in a helium bath every few days. Cryogen-free dilution refrigerators, however, do not use liquid helium and then automatic operation by electricity can be possible from room temperature to the mK region. In near future, therefore, most conventional dilution refrigerators will be replaced by cryogen-free refrigerators because they are easy to operate, do not require maintenance and do not consume helium. We have developed two types of cryogen-free dilution refrigerator. One is directly cooled by a pulse tube refrigerator in the same cryostat using copper thin wires as a thermal link, and the other is cooled by a separate Gifford McMahon refrigerator using circulating helium gas through a flexible syphon tube. The latter has been developed as a vibration-free cryogen-free dilution refrigerator. These two types of cryogen-free dilution refrigerator are compared considering several key points: base temperature, precooling time, minimum temperature and vibration amplitude.

  11. Performance comparison of magnetic refrigeration cycles

    SciTech Connect

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

    1990-01-01

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

  12. Electrodynamic driver for the space thermoacoustic refrigerator (STAR). Master's thesis

    Microsoft Academic Search

    1988-01-01

    The objective of the STAR project is to test and space qualify a new continuous-cycle cryogenic refrigeration system for cooling of sensors and electronics which is based upon the newly discovered thermo-acoustic heat-pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 Hz, and uses acoustic resonance to enhance the overall power density and efficiency.

  13. Efficient Switched Thermoelectric Refrigerators for Cold Storage Applications

    Microsoft Academic Search

    U. Ghoshal; A. Guha

    2009-01-01

    We present switching methods that make thermoelectric refrigerators efficient and optimal for all cold storage applications.\\u000a These temporal methods double the coefficient of performance (COPs) of the refrigerators during cooling transients and allow\\u000a highly energy-efficient operation in the steady state by turning off the thermoelectric devices both electrically and thermally\\u000a so as to avoid back-conduction of heat through the devices.

  14. Recovering and reusing refrigerants

    Microsoft Academic Search

    Katzel

    1994-01-01

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

  15. Stirling-cycle refrigerator

    Microsoft Academic Search

    Nakamura

    1985-01-01

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

  16. A solar thermoelectric refrigerator

    Microsoft Academic Search

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

    1976-01-01

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

  17. Solar thermoelectric refrigerator

    Microsoft Academic Search

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

    1976-01-01

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

  18. Refrigerant leak detector

    NASA Technical Reports Server (NTRS)

    Byrne, E. J.

    1979-01-01

    Quantitative leak detector visually demonstrates refrigerant loss from precision volume of large refrigeration system over established period of time from single test point. Mechanical unit is less costly than electronic "sniffers" and is more reliable due to absence of electronic circuits that are susceptible to drift.

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

    Microsoft Academic Search

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

    1976-01-01

    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

  20. Predicting off-design range and performance of refrigeration cycle with two-stage centrifugal compressor and flash intercooler

    Microsoft Academic Search

    Teemu Turunen-Saaresti; Pekka Rytt; Juha Honkatukia; Jari Backman

    2010-01-01

    A modern refrigeration process requires constant control to provide required cooling for the user. To properly and economically accommodate this need, a wide operation range of the compressor is necessary. Therefore, it is of interest to investigate the off-design operation of a cooling cycle and compressor. The refrigeration cycle equipped with a two-stage centrifugal compressor and a flash intercooler is

  1. Device applications of cryogenic optical refrigeration

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  2. Cryogenic cooling using tunneling structures with sharp energy features

    Microsoft Academic Search

    H. L. Edwards; Q. Niu; G. A. Georgakis; A. L. de Lozanne

    1995-01-01

    Thermoelectric cooling, based upon the extraction of hot electrons and holes from a metallic electron gas, holds unrealized potential for refrigeration at cryogenic temperatures. We discuss the performance of two such electronic refrigerators: the quantum-dot refrigerator (QDR) and the normal-insulator-superconductor (NIS) refrigerator. We obtain the QDR base temperature using a numerical simulation and verify the validity of certain simplifying assumptions

  3. Piezoelectrically-driven Thermoacoustic Refrigerator

    Microsoft Academic Search

    Daniel George Chinn

    2010-01-01

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

  4. Air cooled absorption chillers for solar cooling applications

    NASA Astrophysics Data System (ADS)

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

    1982-03-01

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

  5. Laser cooling of solids

    SciTech Connect

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

    2008-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  7. New technologies for refrigeration without CFCs

    SciTech Connect

    Swift, G.W.

    1992-01-01

    Today the appliance industry and other cooling industries are facing the double challenge of eliminating environmentally harmful CFCs while simultaneously improving energy efficiency. These challenges will force this industry to make tremendous changes and to work out many difficult problems, ranging from choice of technology through production-line retooling to product-liability concerns. Three new cooling technologies--sonic compression, thermoacoustic refrigeration, and Malone refrigeration--have been developed at least in part at Los Alamos National Laboratory. We will discuss the principles, features, and status of each of these three technologies. With these three examples we hope to show that mechanical compression and subsequent evaporation of CFCs is not the only potentially practical way to produce cooling. These examples are only three of many alternative cooling technologies. No new technology can be guaranteed a success before development is complete, from either an economic or engineering point of view. But enough alternative cooling technologies exist, and the probability for success of each technology is high enough, that one or more of these technologies can almost certainly be produced at reasonable cost, eliminate CFCS, and reduce the consumption of electricity.

  8. New technologies for refrigeration without CFCs

    SciTech Connect

    Swift, G.W.

    1992-09-01

    Today the appliance industry and other cooling industries are facing the double challenge of eliminating environmentally harmful CFCs while simultaneously improving energy efficiency. These challenges will force this industry to make tremendous changes and to work out many difficult problems, ranging from choice of technology through production-line retooling to product-liability concerns. Three new cooling technologies--sonic compression, thermoacoustic refrigeration, and Malone refrigeration--have been developed at least in part at Los Alamos National Laboratory. We will discuss the principles, features, and status of each of these three technologies. With these three examples we hope to show that mechanical compression and subsequent evaporation of CFCs is not the only potentially practical way to produce cooling. These examples are only three of many alternative cooling technologies. No new technology can be guaranteed a success before development is complete, from either an economic or engineering point of view. But enough alternative cooling technologies exist, and the probability for success of each technology is high enough, that one or more of these technologies can almost certainly be produced at reasonable cost, eliminate CFCS, and reduce the consumption of electricity.

  9. Isothermally heatsunk diffusion cloud chamber refrigerator

    SciTech Connect

    Menocal, S.G.

    1987-05-05

    This patent describes a diffusion cloud chamber isothermally heatsunk refrigerator which comprises: a heatsink consisting of two phases of a saturated substance existing in thermodynamic equilibrium at constant pressure and therefore at constant temperature, contained in a reservoir; a means of pressure damping to maintain constant pressure, as the ratio of the two phases present changes and introduces volumetric changes in the substance; a cooling member which transfer heat from vapor in contact with the cooling member surface to the ''cold side'' of a Peltier thermoelectric element with which the cooling member is in thermal contact; a Peltier thermoelectric element which removes the heat supplied by the cooling member from its ''cold side'' and pumps it to the ''hot side'' when driven by an electric current; and a means of transferring heat from the ''hot side'' of the Peltier thermoelectric element to the two-phase isothermal substance in the reservoir.

  10. The steady-state modeling and optimization of a refrigeration system for high heat flux removal

    Microsoft Academic Search

    Rongliang Zhou; Tiejun Zhang; Juan Catano; John T. Wen; Gregory J. Michna; Yoav Peles; Michael K. Jensen

    2010-01-01

    Steady-state modeling and optimization of a refrigeration system for high heat flux removal, such as electronics cooling, is studied. The refrigeration cycle proposed consists of multiple evaporators, liquid accumulator, compressor, condenser and expansion valves. To obtain more efficient heat transfer and higher critical heat flux (CHF), the evaporators operate with two-phase flow only. This unique operating condition necessitates the inclusion

  11. Study of an Efficient Dehumidifying System Utilizingm Phase Change of Intermediate Pressure Refrigerant

    Microsoft Academic Search

    Kensaku Maeda; Hideo Inaba

    2005-01-01

    This study has proved a new dehumidifying system that aimed to reduce the sensible heat ratio (SHR) of the cooling process without using additional heat to relieve the recently indicated conflict between energy saving and the dehumidification necessary for keeping adequate indoor air quality (IAQ). In this system, intermediate pressure refrigerant in a vapor compression refrigerating cycle is used as

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

    Microsoft Academic Search

    Susalla

    1988-01-01

    The objective of the STAR project is to test and space qualify a new continuous-cycle cryogenic refrigeration system for cooling of sensors and electronics which is based upon the newly discovered thermoacoustic heat-pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 Hz, and uses acoustic resonance to enhance the overall power density and efficiency.

  13. High power thermoacoustic refrigeration. Annual summary report, 1 June 1995-31 May 1996

    Microsoft Academic Search

    1996-01-01

    The purpose of this research project is to study the fundamental physical processes which are involved in production of high cooling powers from electrically driven thermoacoustic refrigeration. The results of these experimental investigations are then utilized to produce improved designs for the next generation of high power thermoacoustic refrigerators, chillers, and air conditioners. These research objectives are achieved by an

  14. Design and experimental analysis of a carbon dioxide transcritical chiller for commercial refrigeration

    Microsoft Academic Search

    Luca Cecchinato; Manuel Chiarello; Marco Corradi

    2010-01-01

    Carbon dioxide is an interesting solution for commercial refrigeration and in perspective for air-conditioning systems. In this paper a newly developed carbon dioxide transcritical air cooled chiller for refrigerating propylene glycol down to ?8C supply temperature is described. The aim of the project was at optimising the cycle energy efficiency while assuring reliable operation and simple management of the unit.

  15. Low-temperature thermoelectric refrigerating device using current-carrying superconducting mode\\/nonsuperconducting mode junctions

    Microsoft Academic Search

    Skertic

    1991-01-01

    This patent describes a refrigerating device that produces cooling below a preselected temperature. It comprises: a heat sink operable to produce the preselected temperature; a refrigerating unit, including a first piece of a first material that is electrically conducting but not superconducting at the preselected temperature, a second piece of a second material that is superconducting at the preselected temperature,

  16. Effect of heat transfer on the performance of two-stage semiconductor thermoelectric refrigerators

    Microsoft Academic Search

    Lingen Chen; Jun Li; Fengrui Sun; Chih Wu

    2005-01-01

    A model of two-stage semiconductor thermoelectric refrigerators with external heat transfer is proposed. The performance of the refrigerator obeying Newton's heat transfer law is analyzed using the combination of finite-time thermodynamics and nonequilibrium thermodynamics. Two analytical formulas for cooling load versus working electrical current, and the coefficient of performance (COP) versus working electrical current, are derived. For a fixed total

  17. Optimum variables selection of thermoelectric generator-driven thermoelectric refrigerator at different source temperature

    Microsoft Academic Search

    Lingen Chen; Fankai Meng; Yanlin Ge; Fengrui Sun

    2012-01-01

    Based on the finite time thermodynamic model of thermoelectric generator-driven thermoelectric refrigerator with losses of external heat transfer, Joulean heat inside the thermoelectric device and the heat leakage through the thermoelectric couple leg, this paper analysed the effects of generator heat source temperature and refrigerator cooling temperature on the performance of the combined system using the combination of finite time

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

    Microsoft Academic Search

    M. Hekkenberg; Anton J. M. Schoot Uiterkamp

    2007-01-01

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

  19. Thermoacoustic engines and refrigerators

    SciTech Connect

    Swift, G.

    1996-12-31

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

  20. Joule Thomson refrigerator

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  1. Save with Hybrid Refrigeration

    E-print Network

    Chung, C. W.

    1985-01-01

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

  2. Improving Control in a Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Borders, James; Pearson, David; Prina, Mauro

    2005-01-01

    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.

  3. Measurements of the efficiency and refrigeration power of pulse-tube refrigerators

    SciTech Connect

    Herrmann, S.; Radebaugh, R.

    1986-09-01

    Pulse-tube or thermoacoustic refrigerators have the potential for high reliability since they require only one moving part - an oscillating piston or diaphragm at room temperature. If a tube is closed at one end and connected to a pressure-wave generator at the open end, and if the phase angle between mass flow and pressure is shifted from 90/sup 0/, then refrigeration occurs at the open end. The shift in phase angle can be realized by thermal relaxation between the gas and the tube walls or by an orifice at the closed end. A low temperature of 60 K using helium gas in a one-stage orifice pulse tube has been achieved at NBS. The report describes the first measurements of the efficiency, refrigeration power, and refrigeration power per unit mass flow, for three pulse-tube refrigerators. Three tube sizes, differing in length and diameter, were studied over a frequency range of 3 to 11.5 Hz. Cooling efficiencies as high as 90% of the Carnot efficiency were obtained when compressor and regenerator losses are neglected.

  4. Evaluating energy dissipation during expansion in a refrigeration cycle using flue pipe acoustic resonators

    E-print Network

    Luckyanova, Maria N. (Maria Nickolayevna)

    2008-01-01

    This research evaluates the feasibility of using a flue pipe acoustic resonator to dissipate energy from a refrigerant stream in order to achieve greater cooling power from a cryorefrigeration cycle. Two models of the ...

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

    E-print Network

    Greenblatt, Jeffery B.

    2013-01-01

    refrigeration technologies Survey response Manufacturer website information Vapor compression Thermoelectricrefrigeration products that use cooling technology other than vapor compression (thermoelectricrefrigeration technology, as fraction of identified units Manufacturer website information Vapor compression Thermoelectric

  6. Cooling Towers, The Neglected Energy Resource

    E-print Network

    Burger, R.

    1985-01-01

    Loving care is paid to the compressors, condensers, and computer programs of refrigeration systems. When problems arise, operator: run around in circles with expensive "fixes", but historically ignore the poor orphan, the cooling tower perched...

  7. Polymer-based electrocaloric cooling devices

    DOEpatents

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

    2014-10-28

    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).

  8. Dry dilution refrigerator with 4He-1 K-loop

    NASA Astrophysics Data System (ADS)

    Uhlig, Kurt

    2015-03-01

    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.

  9. Laser cooling of infrared sensors.

    SciTech Connect

    Hasselbeck, M. P. (Michael P.); Sheik-Bahae, M (Mansoor); Thiede, J. (Jared); Distel, J. R. (James R.); Greenfield, S. R. (Scott R.); Patterson, Wendy M.; Bigotta, S.; Imangholi, B.; Seletskiy, D. (Denis); Bender, D.; Vankipuram, V.; Vadiee, N.; Epstein, Richard I.

    2004-01-01

    We present an overview of laser cooling of solids. In this all-solid-state approach to refrigeration, heat is removed radiatively when an engineered material is exposed to high power laser light. We report a record amount of net cooling (88 K below ambient) that has been achieved with a sample made from doped fluoride glass. Issues involved in the design of a practical laser cooler are presented. The possibility of laser cooling of semiconductor sensors is discussed.

  10. Macroscopic Refrigeration Using Superconducting Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Lowell, Peter; O'Neil, Galen; Underwood, Jason; Zhang, Xiaohang; Ullom, Joel

    2014-03-01

    Sub-kelvin temperatures are often a prerequisite for modern scientific experiments, such as quantum information processing, astrophysical missions looking for dark energy signatures and tabletop time resolved x-ray spectroscopy. Existing methods of reaching these temperatures, such as dilution refrigerators, are bulky and costly. In order to increase the accessibility of sub-Kelvin temperatures, we have developed a new method of refrigeration using normal-metal/insulator/superconductor (NIS) tunnel junctions. NIS junctions cool the electrons in the normal metal since the hottest electrons selectively tunnel from the normal metal into the superconductor. By extending the normal metal onto a thermally isolated membrane, the cold electrons can cool the phonons through the electron-phonon coupling. When these junctions are combined with a pumped 3He system, they provide a potentially inexpensive method of reaching these temperatures. Using only three devices, each with a junction area of approximately 3,500 ?m2, we have cooled a 2 cm3 Cu plate from 290 mK to 256 mK. We will present these experimental results along with recent modeling predictions that strongly suggest that further refinements will allow cooling from 300 mK to 120 mK. This work is supported by the NASA APRA program.

  11. Development test on 2 K cooling systems

    NASA Astrophysics Data System (ADS)

    Okudaira, Toshiaki; Fujii, Genshirou

    1993-03-01

    Topics discussed include: the detail of proposal; configuration of the laboratory dilution refrigerator; the adiabatic vacuum section of the dilution refrigerator; the relationship between refrigerating capability and cooling temperature; phase diagram and vapor pressure curves of the He-3 and He-4; the fractionation chamber and dilution chamber; separation control by electric field of He-3 rich and He-4 rich phases; mixer utilizing electric field; restriction of liquid; the mixture cell; and continuous operation type dilution type refrigerator. This presentation is represented by viewgraphs only.

  12. Waste Heat Recovery from Refrigeration

    E-print Network

    Jackson, H. Z.

    1982-01-01

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

  13. A model for exergy analysis and thermodynamic bounds of Stirling refrigerators

    NASA Astrophysics Data System (ADS)

    Razani, A.; Dodson, C.; Roberts, T.

    2010-04-01

    A thermodynamic model based on exergy flow through a Stirling Refrigerator is developed. Important irreversibilities of the refrigerator due to external heat transfer with the reservoirs, heat leak, flow and heat transfer in regenerator are included in the model. Expansion and compression efficiencies are introduced in the model to account for the losses in these processes. The effect of a control phase shift between the mass flow rate and pressure across regenerator on the performance of the refrigerator is presented. Analytical solutions representing important quantities in the design of Stirling refrigerators such as the load curve, cooling power and efficiency in terms of basic system input parameters are developed. Thermodynamic bounds for the performance of Stirling refrigerators are obtained. Results indicating a compromise between cooling power and efficiency that are dependent on the constraint of the system are presented and discussed.

  14. Parametric amplifier with thermoelectric refrigeration

    Microsoft Academic Search

    M. Uenohara; R. Wolfe

    1961-01-01

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

  15. Performance of the IFSMTF helium refrigerator in partial-array tests

    SciTech Connect

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

    1985-01-01

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

  16. The Performance Optimization of a Thermoacoustic Refrigeration MicroCycle

    Microsoft Academic Search

    Kan Xuxian; Wu Feng; Shu Anqing; Yu Shicheng; Wu Kun; Zou Wenjing

    2009-01-01

    Performance analysis and optimization of the thermoacoustic refrigeration micro-cycle which is important to the energy conversion between thermal and acoustic through the thermoacoustic effect has been performed using finite time thermodynamics. The analytical expressions about the ecological function, as well as the relation between the ecological and the COP are derived. The relations between the cooling load and the COP,

  17. Optimization study of combined refrigeration cycles driven by an engine

    Microsoft Academic Search

    Yang Zhao; Zhang Shigang; Zhao Haibe

    2003-01-01

    In order to utilize the waste heat efficiently for a gas engine-driven heat pump running in a cooling mode, this paper studies two combined absorption\\/compression refrigeration cycles using ammonia and water as the working fluid. By analyzing the operating characteristics of the combined cycles that make efficient use of both the work and the heat output of an engine, this

  18. Thermoeconomic optimization of an irreversible Stirling cryogenic refrigerator cycle

    Microsoft Academic Search

    S. K. Tyagi; G. Lin; S. C. Kaushik; J. Chen

    2004-01-01

    This communication presents the thermoeconomic optimization of an irreversible Stirling cryogenic refrigerator cycle. The external irreversibility is due to finite temperature difference between the working fluid and the external reservoirs while the internal irreversibility is due to the regenerative heat loss. The thermoeconomic function is defined as the cooling load divided by the total cost of the system plus the

  19. A novel pressurized CHP system with water extraction and refrigeration

    Microsoft Academic Search

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

    2010-01-01

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

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

    Microsoft Academic Search

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

    2012-01-01

    Low energy efficiency and limitations of cooling temperatures in the ejector refrigeration systems (ERSs) are major obstacles for its widespread use. The application of binary or multicomponent fluids may prove to be one of the successful ways to increase the ERS performance by 3050%. Zeotropic mixtures, which have unlimited solubility and evaporate at specified pressures and varying temperatures, are considered

  1. Scroll compressor modelling for heat pumps using hydrocarbons as refrigerants

    E-print Network

    Paris-Sud XI, Universit de

    1 Scroll compressor modelling for heat pumps using hydrocarbons as refrigerants Paul BYRNE and to install heat pumps in unoccupied spaces. Nevertheless manufacturers keep working on components for hydrocarbons. In the frame of a research project on heat pumps for simultaneous heating and cooling, an R407C

  2. Cooling Unit for Computer Chip by using Boiling Heat Transfer

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Kiyoshi; Terao, Tadayoshi; Kobayashi, Kazuo

    In recent years, the heating value of CPU has been increasing rapidly in proportion to the improvement of computer performance. Therefore computer industry is requiring the new cooling unit having high cooling performance for CPU adaptable to high heating value and high heat flux. In the past the cooling unit for CPU is used with air-cooling aluminum fin, but it can not be adaptable to high heating value. We have developed a new compact boiling refrigerant type cooling unit for CPU having high cooling performance in comparing with air-cooling aluminum fin. This paper described the cooling performance and pressure drop characteristics of the boiling refrigerant type cooling unit for CPU. The characteristics were clarified by testing the cooling unit under various test conditions, which were different Reynolds number, various sizes of cooling unit and various inclination angles. Furthermore the equations to predict cooling performance and pressure drop which are necessary on design of the cooling unit were proposed.

  3. Design optimization of thermoacoustic refrigerators

    Microsoft Academic Search

    Martin Wetzel; Cila Herman

    1997-01-01

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

  4. 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...

  5. Solar-Powered Refrigeration System

    Microsoft Academic Search

    Michael K. Ewert; David J. Bergeron III

    2002-01-01

    A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant

  6. Low-temperature magnetic refrigerator

    DOEpatents

    Barclay, J.A.

    1983-05-26

    The invention relates to magnetic refrigeration and more particularly to low temperature refrigeration between about 4 and about 20 K, with an apparatus and method utilizing a belt of magnetic material passed in and out of a magnetic field with heat exchangers within and outside the field operably disposed to accomplish refrigeration.

  7. Influence of irreversible losses on the performance of a two-stage magnetic Brayton refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Chen, J.; Lin, G.; Brck, E.

    2010-03-01

    The general performance characteristics of a two-stage magnetic Brayton refrigeration cycle consisting of three constant magnetic fields and three irreversible adiabatic processes are investigated. Based on the thermodynamic properties of a magnetic material and the irreversible cycle model of a two-stage Brayton refrigerator, expressions for the cooling load and coefficient of performance of the refrigeration system are derived. The influence of the finite-rate heat transfer in the heat exchange processes, irreversibilities in the three adiabatic processes, ratios of two magnetic fields in the three constant magnetic field processes, and heat leak losses between two heat reservoirs on the performance of the two-stage magnetic Brayton refrigeration cycle are analyzed in detail. Some important performance curves, which can reveal the general characteristics of the refrigeration system, are presented and the maximum values of cooling load and coefficient of performance are numerically calculated. The optimal choices and matches of other parameters at the maximum cooling load or the maximum coefficient of performance are discussed and the optimally operating regions of some important parameters in the refrigeration system are determined. The results obtained here are compared with those derived from other models of the magnetic Brayton refrigeration cycles, and consequently, the advantage of an inter-cooled process is expounded.

  8. Step piston pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Zhu, Shaowei

    2014-11-01

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

  9. Optimize refrigeration design

    SciTech Connect

    Baggio, J.L.

    1984-06-01

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

  10. Solar Powered Refrigeration System

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  11. Thermoacoustic engines and refrigerators

    SciTech Connect

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

    1995-07-01

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

  12. Design of thermoacoustic refrigerators

    Microsoft Academic Search

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

    2002-01-01

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

  13. Thermoacoustic Refrigeration Device

    Microsoft Academic Search

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

    2009-01-01

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

  14. Education in Helium Refrigeration

    SciTech Connect

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

    2004-06-23

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

  15. Improved cryogenic refrigeration system

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1967-01-01

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

  16. Seawater refrigerating system failure

    Microsoft Academic Search

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

    1995-01-01

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

  17. Historical and present developments of ejector refrigeration systems with emphasis on transcritical carbon dioxide air-conditioning applications

    Microsoft Academic Search

    Stefan Elbel

    2011-01-01

    This paper gives an overview of historical and present developments on how ejectors can be utilized to improve the performance of air-conditioning and refrigeration systems. Research on ejector refrigeration cycles that utilize low-grade energy sources to produce cooling is summarized. Another major class of ejector refrigeration cycles that is described tries to recover expansion work by means of a two-phase

  18. Four-level refrigerator driven by photons

    NASA Astrophysics Data System (ADS)

    Wang, Jianhui; Lai, Yiming; Ye, Zhuolin; He, Jizhou; Ma, Yongli; Liao, Qinghong

    2015-05-01

    We propose a quantum absorption refrigerator driven by photons. The model uses a four-level system as its working substance and couples simultaneously to hot, cold, and solar heat reservoirs. Explicit expressions for the cooling power Q?c and coefficient of performance (COP) ?COP are derived, with the purpose of revealing and optimizing the performance of the device. Our model runs most efficiently under the tight coupling condition, and it is consistent with the third law of thermodynamics in the limit T ?0 .

  19. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

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

    1987-01-01

    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.

  20. Measurement of two-phase refrigerant liquid-vapor mass flow rate. Part 3: Combined turbine and venturi meters and comparison with other methods

    SciTech Connect

    Abdul-Razzak, A.; Shoukri, M.; Chang, J.S. [McMaster Univ., Hamilton, Ontario (Canada)

    1995-12-31

    In determining the mass flow rate of refrigerant R-134a liquid-vapor in a horizontal tube, a simple method that combines the outputs of venturi and turbine flowmeters, without the need for void fraction or quality measurement, was examined. The results showed that this method can be used to determine the two-phase mass flow rate relatively well for the entire quality range. This method was particularly accurate in determining the mass flow rate data in the high-quality range, i.e., in annular flow. Moreover, this method also showed a reasonable accuracy in predicting the void fraction. The use of this method in predicting the two-phase mass flow rate was compared with the use of a venturi meter or a turbine flowmeter and a void fraction meter. The comparison showed that at qualities higher than 0.6, the present method, which combines the output signals of both the turbine and venturi meters, is superior to those that use one of the flow signals and void fraction and/or quality measurement. At lower qualities, the present method still offers a fairly accurate technique for measuring the liquid-vapor refrigeration mass flow rate.

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

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

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

  2. Salt pill design and fabrication for adiabatic demagnetization refrigerators

    NASA Astrophysics Data System (ADS)

    Shirron, Peter J.; McCammon, Dan

    2014-07-01

    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.

  3. Salt Pill Design and Fabrication for Adiabatic Demagnetization Refrigerators

    NASA Technical Reports Server (NTRS)

    Shirron, Peter J.; Mccammon, Dan

    2014-01-01

    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.

  4. Integrated NIS electron-tunnelling refrigerator/superconducting bolometer

    NASA Astrophysics Data System (ADS)

    Silverberg, R. F.; Benford, D. J.; Chen, T. C.; Chervenak, J.; Finkbeiner, F.; Moseley, S. H.; Duncan, W. D.; Miller, N. A.; Schmidt, D. R.; Ullom, J. N.

    2006-04-01

    We describe progress in the development of a close-packed array of bolometers designed for use in photometric applications at millimeter wavelengths from ground-based telescopes. Each bolometer in the array will use a proximity-effect Transition Edge Sensor (TES) sensing element and each will have integrated Normal-Insulator-Superconductor (NIS) refrigerators to cool the bolometer below the thermal reservoir temperature. The NIS refrigerators and acoustic-phonon-mode-isolated bolometers are fabricated on silicon. The radiation absorbing element is mechanically suspended by four legs, whose dimensions are used to control and optimize the thermal conductance of the bolometer. Using the technology developed at NIST, we fabricate NIS refrigerators at the base of each of the suspension legs. The NIS refrigerators remove hot electrons by quantum-mechanical tunneling and are expected to cool the biased (10 pW) bolometers to <170 mK while the bolometers are inside a pumped 3He-cooled cryostat operating at 280 mK. This significantly lower temperature at the bolometer allows the detectors to approach background-limited performance despite the simple cryogenic system.

  5. The Quantum Refrigerator: The quest for absolute zero

    E-print Network

    Yair Rezek; Peter Salamon; Karl Heinz Hoffmann; Ronnie Kosloff

    2008-08-04

    The scaling of the optimal cooling power of a reciprocating quantum refrigerator is sought as a function of the cold bath temperature as $T_c \\to 0$. The working medium consists of noninteracting particles in a harmonic potential. Two closed-form solutions of the refrigeration cycle are analyzed, and compared to a numerical optimization scheme, focusing on cooling toward zero temperature. The optimal cycle is characterized by linear relations between the heat extracted from the cold bath, the energy level spacing of the working medium and the temperature. The scaling of the optimal cooling rate is found to be proportional to $T_c^{3/2}$ giving a dynamical interpretation to the third law of thermodynamics.

  6. A four-bed mass recovery adsorption refrigeration cycle driven by low temperature waste\\/renewable heat source

    Microsoft Academic Search

    K. C. A. Alam; A. Akahira; Y. Hamamoto; A. Akisawa; T. Kashiwagi

    2004-01-01

    The study deals with an advanced four-bed mass recovery adsorption refrigeration cycle driven by low temperature heat source. The proposed cycle consists of two basic adsorption refrigeration cycle. The heat source rejected by one cycle is used to power the second cycle. Due to the cascading use of heat and cooling source, all major components of the system maintain different

  7. General performance characteristics and parametric optimum criteria of a nano-thermoelectric refrigerator with an external magnetic field

    Microsoft Academic Search

    Hao Wang; Guoxing Wu; Jian Xie

    2012-01-01

    In the paper, we describe a single-level quantum dot with an external magnetic field that works as a nano-thermoelectric refrigerator. Based on the model, the expressions for the cooling rate , the power input (P) and the coefficient of performance (?) are derived. The effects of the magnetic field strength and the level energy on the performance of the refrigerator

  8. Effects of internal irreversibility and heat leakage on the finite time thermoeconomic performance of refrigerators and heat pumps

    Microsoft Academic Search

    Ali Kodal; Bahri Sahin; Tamer Yilmaz

    2000-01-01

    By using finite time thermodynamic theory, a performance analysis based on the thermoeconomic criterion has been performed for an irreversible refrigerator and a heat pump. The thermoeconomic objective function is defined as the cooling load for the refrigerator and the heating load for the heat pump per unit total cost. The optimal performances and design parameters which maximize the objective

  9. Optimal performance of a thermoelectric refrigerator

    Microsoft Academic Search

    Jincan Chen; Zijun Yan

    1994-01-01

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

  10. Determination of a vapor compression refrigeration system refrigerant charge

    Microsoft Academic Search

    Chun-Xin Yang; Chao-Bin Dang

    1995-01-01

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

  11. Discussion of Refrigeration Cycle Using Carbon Dioxide as Refrigerant

    NASA Astrophysics Data System (ADS)

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

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

  12. 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_ ...

  13. Experimental realization of a Coulomb blockade refrigerator

    NASA Astrophysics Data System (ADS)

    Feshchenko, A. V.; Koski, J. V.; Pekola, J. P.

    2014-11-01

    We present an experimental realization of a Coulomb blockade refrigerator (CBR) based on a single-electron transistor (SET). In the present structure, the SET island is interrupted by a superconducting inclusion to permit charge transport while preventing heat flow. At certain values of the bias and gate voltages, the current through the SET cools one of the junctions. The measurements follow the theoretical model down to 80 mK, which was the base temperature of the current measurements. The observed cooling increases rapidly with decreasing temperature, in agreement with the theory, reaching about a 15 mK drop at the base temperature. The CBR appears as a promising electronic cooler at temperatures well below 100 mK.

  14. The HAWC and SAFIRE Adiabatic Demagnetization Refrigerators

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

  15. Cooling Shelf For Electronic Equipment

    NASA Technical Reports Server (NTRS)

    Tanzer, Herbert J.

    1989-01-01

    Heat-pipe action cools and maintains electronics at nearly constant temperature. System designed to control temperatures of spacecraft shelves or baseplates by combining honeycomb sandwich panel with reservoir of noncondensable gas and processing resulting device as variable-conductance heat pipe. Device provides flat surface for mounting heat-dissipating electronics that is effectively cooled and maintained at nearly constant temperature. Potentially useful in freeze drying, refrigeration, and air conditioning.

  16. A portable direct-PV thermoelectric vaccine refrigerator with ice storage through heat pipes

    Microsoft Academic Search

    Somchai Jiajitsawat; John Duffy

    2008-01-01

    The objective of this research work was to develop a portable solar refrigeration system capable of maintaining vaccine temperatures between 2 C and 8 C. The main system under this study consisted of thermoelectric modules as cooling generators with latent heat energy storage (LHES) using water as cooling backup along with heat pipes as passive temperature controllers to avoid freezing

  17. Belgirate, Italy, 28-30 September 2005 THERMIONIC REFRIGERATION WITH PLANAR AND NONPLANAR ELECTRODES

    E-print Network

    Paris-Sud XI, Universit de

    Belgirate, Italy, 28-30 September 2005 THERMIONIC REFRIGERATION WITH PLANAR AND NONPLANAR power densities in micro- and power- electronic components thermoelectric cooling becomes more and more, thermoelectric devices can cool in a controlled way in the immediate neighbourhood of the hot spots of the power

  18. Page 1 of 4 Refrigerant Charge Verification: 70F Return Air Requirement

    E-print Network

    Page 1 of 4 Refrigerant Charge Verification: 70F Return Air Requirement This article describes to the conditioned air slows the overall rate of cooling of the dwelling's mixed air during the test, extending. Addition of supplemental heating to the conditioned air will counteract a portion of the cooling effect

  19. Advanced Desiccant Cooling and Dehumidification Program

    Microsoft Academic Search

    Slayzak

    1999-01-01

    The use of dessicant materials for cooling and dehumidification is an effective, economical, environmentally safe method for meeting indoor air quality standards established by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). To maximize the technology's potential for reducing energy consumption and improving indoor air quality, DOE established the Advanced Desiccant Cooling and Dehumidification Program. The National Renewable

  20. Magnetic cooling by an adiabatic spin reorientation

    Microsoft Academic Search

    T. Morishita; K. Tsushima

    1984-01-01

    A new method of magnetic cooling is proposed by using an adiabatic entropy change associated with a spin reorientation transition. This is available for a magnetic refrigerator operating under a weaker magnetic field than an ordinary method using a superconducting magnet to cool a paramagnetic crystal. The single crystal and sintered samples of ErCrO were adopted as a prototype material.

  1. Investigation of the operating processes of an absorption lithium-bromide refrigeration machine with a spray generator

    Microsoft Academic Search

    L. M. Rosenfeld; V. I. Dogolyatskiy

    1975-01-01

    The results of an experimental investigation of a refrigeration machine with a spray generator are discussed. It was concluded after several tests that the spray generator increased the cooling efficiency by 10 to 15%. Phase diagrams are shown.

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

    E-print Network

    Schor, Alisha R. (Alisha Robin)

    2007-01-01

    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 ...

  3. High-efficiency gas heat pump air-conditioner equipped with absorption refrigerator

    NASA Astrophysics Data System (ADS)

    Kawakami, Ryuichiro; Imai, Kazuya; Nakajima, Hidekazu; Okamoto, Hiroaki; Hihara, Eiji

    To improve rated efficiency and partial load efficiency of gas engine heat pump (GHP), we are developing a new type air-cooled absorption refrigerator which is driven by the engine waste hot water. To shape the compact absorption refrigerator body that was able to be built into the space of a GHP outdoor-unit, an air-cooled sub-cooled adiabatic absorber and flowing liquid film plate type generator were newly developed. Maximum cooling capacity was increased about 20%, rated load COP was increased 40%, and partial load COP was increased 46% or less, as a result of the combination examination of a prototype 8.0kW absorption refrigerator and a 56kW GHP at a laboratory.

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

    NASA Astrophysics Data System (ADS)

    Susalla, Michael P.

    1988-06-01

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

  5. Effects of refrigeration in a transportable cryogenic aerospace application

    SciTech Connect

    Donovan, B.D.; Mahefkey, T. [Wright Lab., Wright-Patterson AFB, OH (United States); Ramalingam, M.L. [UES, Inc., Dayton, OH (United States)

    1995-12-31

    Preliminary feasibility studies, based on refrigeration thermodynamics, have been conducted for candidate power conditioning components in a 1MWe terrestrial/transportable cryogenic power system. The cryogenic power system being considered has a super conducting generator for high power applications such as the power source for a Ground Based Radar (GBR) System. While the superconducting generator operates at 77K or lower, the present analysis indicates that significant benefits cannot be derived by cooling the various components of the power conditioning system to such low temperatures. It was found that, by operating the power conditioning component at 150K instead of at 77K the overall system efficiency was not jeopardized by way of large input power requirements to dissipate small refrigerator loads. This is an acute problem as current cryogenic refrigeration systems allow for very low levels of energy dissipation while performing at about 7 to 10% of the Carnot coefficients of performance (COP) between 300K and 77K.

  6. The Hall D solenoid helium refrigeration system at JLab

    SciTech Connect

    Laverdure, Nathaniel A. [JLAB; Creel, Jonathan D. [JLAB; Dixon, Kelly d. [JLAB; Ganni, Venkatarao [JLAB; Martin, Floyd D. [JLAB; Norton, Robert O. [JLAB; Radovic, Sasa [JLAB

    2014-01-01

    Hall D, the new Jefferson Lab experimental facility built for the 12GeV upgrade, features a LASS 1.85 m bore solenoid magnet supported by a 4.5 K helium refrigerator system. This system consists of a CTI 2800 4.5 K refrigerator cold box, three 150 hp screw compressors, helium gas management and storage, and liquid helium and nitrogen storage for stand-alone operation. The magnet interfaces with the cryo refrigeration system through an LN2-shielded distribution box and transfer line system, both designed and fabricated by JLab. The distribution box uses a thermo siphon design to respectively cool four magnet coils and shields with liquid helium and nitrogen. We describe the salient design features of the cryo system and discuss our recent commissioning experience.

  7. Performance analysis and optimization of high capacity pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Ghahremani, Amir R.; Saidi, M. H.; Jahanbakhshi, R.; Roshanghalb, F.

    High capacity pulse tube refrigerator (HCPTR) is a new generation of cryocoolers tailored to provide more than 250 W of cooling power at cryogenic temperatures. The most important characteristics of HCPTR when compared to other types of pulse tube refrigerators are a powerful pressure wave generator, and an accurate design. In this paper the influence of geometrical and operating parameters on the performance of a double inlet pulse tube refrigerator (DIPTR) is studied. The model is validated with the existing experimental data. As a result of this optimization, a new configuration of HCPTR is proposed. This configuration provides 335 W at 80 K cold end temperature with a frequency of 50 Hz and COP of 0.05.

  8. THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS

    EPA Science Inventory

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

  9. 49 CFR 173.174 - Refrigerating machines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  10. 49 CFR 173.174 - Refrigerating machines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  11. 2012 International Conference on Medical Physics and Biomedical Engineering Thermal Economic Analysis on LiBr Refrigeration -Heat Pump System Applied in CCHP System

    NASA Astrophysics Data System (ADS)

    Zhang, CuiZhen; Yang, Mo; Lu, Mei; Zhu, Jiaxian; Xu, Wendong

    LiBr refrigeration cooling water contains a lot of low-temperature heat source, can use this part of the heat source heat boiler feed water. This paper introduced LiBr refrigeration - heat pump system which recovery heat of the LiBr refrigeration cooling water by heat pump system to heat the feed water of boiler. Hot economic analysis on the system has been performed based on the experimental data. Results show that LiBr refrigeration-heat pump system brings 26.6 percent decrease in primary energy rate consumption comparing with the combined heat and power production system(CHP) and separate generation of cold;

  12. Experimental study on cool storage air-conditioning system with spherical capsules packed bed

    Microsoft Academic Search

    Guiyin Fang; Shuangmao Wu; Xu Liu

    2010-01-01

    An experimental investigation on operation characteristics of cool storage air-conditioning system with spherical capsules packed bed was performed in this paper. The experimental system of cool storage air-conditioning system with spherical capsules packed bed was set up. The performance parameters such as the evaporation pressure and the condensation pressure of refrigeration system, the refrigeration capacity and the coefficient of performance

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

    NASA Astrophysics Data System (ADS)

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

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

  14. Natural refrigerants for refrigeration and air-conditioning systems

    Microsoft Academic Search

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

    1997-01-01

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

  15. Dynamics and particle image velocimetry measurements of miniaturized thermoacoustic refrigerators

    NASA Astrophysics Data System (ADS)

    El-Gendy, Husam El-Deen Mohamad

    This research deals with the design and characterization of the dynamics of miniaturized thermoacoustic refrigerators (in the audible frequency range 4000 Hz) using a random array of cotton wool as the stack and a commercial piezoelectric loudspeaker as the acoustic driver. Also of primary interest is the optimization of the refrigerator by investigating the factors affecting its performance such as the stack configuration, the acoustic drive ratio, the acoustic pressure and the mean pressure in the refrigerator. Experimental measurements of cooling power, and stray heat leaks were conducted. Digital particle image velocimetry (DPIV) was used to study the acoustic flow field in the refrigerator and to correlate measurements using PIV to the characteristic acoustic measurements. A temperature difference between the refrigerator's cold and hot heat exchangers of 13C was obtained under optimized experimental conditions. Air at atmospheric pressure was used as the working gas, and an electric power to the acoustic driver of 2 W produced 159 dB of sound, which pumped heat by the stack. Higher sound levels would raise the performance. Results showed that the cotton stack performs well at atmospheric pressure rather than higher mean pressures where nonlinear and viscous losses affect its performance. PIV measurements, such as imaged velocity fields and gas flows, showed an excellent correlation with the acoustic pressure measurements in the refrigerator. Extreme care was taken, by investigating different PIV parameters, to fulfill the conditions that distinguish between the oscillating first-order velocity field, such as the acoustic particle velocity, and the second-order nonoscillating (steady state) fields, such as acoustic streaming. Results also showed that Rayleigh streaming, produced by and superimposed on, the oscillating particle velocity, is one of the effects affecting the performance of the refrigerator, where the time it takes the streaming to be in the steady state is comparable to the time it takes the refrigerator to stabilize at its peak DeltaT. In this research the dynamics of the thermoacoustic refrigerator have been studied to optimize the operating experimental conditions and to improve the refrigerator's performance.

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

    PubMed

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

    2003-04-01

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

  17. Performance of absorption cycle operating with low thermal-potential energy sources for direct-contact cooling applications

    Microsoft Academic Search

    I. Borde; I. Yaron; M. Jelinek

    1977-01-01

    Low thermal-potential energy sources, e.g., waste heat, solar energy, etc., can be utilized for refrigeration or cooling in various industrial applications. Suitable working solutions have been selected to operate in an absorption refrigeration cycle. A computer program delineated the ranges of feasible operating parameters and chose the optimal operating conditions for given energy sources, refrigeration requirements and ambient conditions. The

  18. Exergoeconomic performance optimization for a steady-flow endoreversible refrigerator cycle model including five typical cycles

    Microsoft Academic Search

    Xuxian Kan; Lingen Chen; Fengrui Sun; Feng Wu

    2010-01-01

    The operation of a universal steady-flow endoreversible refrigeration cycle model consisting of a constant thermal-capacity heating branch, a constant thermal-capacity cooling branch and two adiabatic branches is viewed as a production process with exergy as its output. The finite-time exergoeconomic performance optimization of the refrigeration cycle is investigated by taking profit rate as the optimization objective. The relations between the

  19. Carbonammonia pairs for adsorption refrigeration applications: ice making, air conditioning and heat pumping

    Microsoft Academic Search

    Z. Tamainot-Telto; S. J. Metcalf; R. E. Critoph; Y. Zhong; R. Thorpe

    2009-01-01

    A thermodynamic cycle model is used to select an optimum adsorbent-refrigerant pair in respect of a chosen figure of merit that could be the cooling production (MJm?3), the heating production (MJm?3) or the coefficient of performance (COP). This model is based mainly on the adsorption equilibrium equations of the adsorbentrefrigerant pair and heat flows. The simulation results of 26 various

  20. A closed-cycle 1 K refrigeration cryostat

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  1. Optimization of the performance characteristics in an irreversible magnetic Brayton refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Liu, Sanqiu

    2008-06-01

    An irreversible cycle model of magnetic Brayton refrigerators is established, in which the thermal resistance and irreversibility in the two adiabatic processes are taken into account. Expressions for several important performance parameters, such as the coefficient of performance, cooling rate and power input are derived. Moreover, the optimal performance parameters are obtained at the maximum coefficient of performance. The optimization region (or criteria) for an irreversible magnetic Brayton refrigerator is obtained. The results obtained here have general significance and will be helpful to understand deeply the performance of a magnetic Brayton refrigeration cycle.

  2. Thermoelectrically Cooled GaAIAs Laser Illuminator.

    PubMed

    Herzog, D G; Kressel, H

    1970-10-01

    Required operating wavelengths in GaAs injection lasers have generally determined the operating temperature, preventing the use of optimum refrigeration systems. Recent advances in GaAIAs injection lasers have produced high efficiency lasers with selectable wavelengths from 0.8 microm to 0.9 microm. This paper discusses the refrigeration considerations for GaAIAs lasers. The basis for selecting the thermoelectric refrigerator is presented and the solution of the optical-electronic interface problems are discussed. Finally, the actual design and performance characteristics of the individual laser arrays and a thermoelectrically cooled, GaAIAs illuminator are described. PMID:20094242

  3. MFTF-B refrigerator analysis

    SciTech Connect

    NONE

    1995-02-10

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

  4. Thermoacoustic Refrigerator Design and Performance

    Microsoft Academic Search

    Thomas James Hofler

    1986-01-01

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

  5. Regenerative Sorption Refrigerator

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  6. The refrigerator revolution

    SciTech Connect

    Ayres, E.; French, H.

    1996-09-01

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

  7. Thermoacoustic Duplex Technology for Cooling and Powering a Venus Lander

    NASA Astrophysics Data System (ADS)

    Walker, A. R.; Haberbusch, M. S.; Sasson, J.

    2015-04-01

    A Thermoacoustic Stirling Heat Engine (TASHE) is directly coupled to a Pulse Tube Refrigerator (PTR) in a duplex configuration, providing simultaneous cooling and electrical power, thereby suiting the needs of a long-lived Venus lander.

  8. Cooling Towers, The Neglected Energy Resource

    E-print Network

    Burger, R.

    1987-01-01

    COOLING TOWERS, THE NEGLECTED ENERGY RESOURCE ROBERT BURGER President, Burger Associates, Inc. Dallas, Texas (USA) Loving care is paid to the compress ors, condensers, and computer programs of refrigeration and air conditioning systems... Handbook Chapter 21, 2. Energy Conservation page 11, (1975). 3. Colder Water 5. Robert Burger, "Cooling Tower Technology" Chapter 8, "Thermal Engineel'ing", (1979). 4. Greater GPM Cooling 6. A Texas college, test report and loca 5. Money Making...

  9. Cryogenic refrigeration thermodynamics for a power conditioning electronic component

    SciTech Connect

    Ramalingam, M.L. [UES, Inc., Dayton, OH (United States); Donovan, B.D.; Beam, J.E. [Wright Lab./POO, Wright-Patterson AFB, OH (United States)

    1996-12-31

    Recent developments in cryogenic technologies have indicated that cryogenically cooling power conditioning equipment in multi-megawatt power systems will reduce system mass, volume and complexity. Most of the mass and volume saving results from the greatly increased electrical conductivity of metals cooled to cryogenic temperatures. Preliminary feasibility studies, based on refrigeration thermodynamics, have been conducted for candidate power conditioning components in a terrestrial/transportable cryogenic power system geared towards a radar application. Based on the analysis, it was found that by operating a general power conditioning component at 150 K instead of at 77 K the overall system efficiency was not jeopardized by way of large input power requirements to dissipate small refrigerator loads. This is an acute problem as some of the current cryogenic refrigeration systems allow for very low levels of energy dissipation while performing at about 7 to 10% of the Carnot coefficient of performance (COP) between 300 K and 77 K. However, there are coolers based on the Stirling cycle, that offer enhanced performance at 150 K (Donovan, 1995). After a general application of the Breakeven Refrigeration Thermodynamics (BRT) to an electronic power conditioning component, BRT was specifically considered for multilayer ceramic capacitors at cryogenic temperatures. It was found that in order not to pay a power penalty for cooling a capacitor to 77 K, the cryocooled Equivalent Series Resistance (ESR) value would have to be a factor of forty lower than that of a conventional capacitor ESR value if using a Gifford-McMahon cooling cycle, or a factor of twelve better for a more efficient Stirling cycle.

  10. A comparison of projected thermoelectric and thermionic refrigerators

    Microsoft Academic Search

    G. S. Nolas; H. J. Goldsmid

    1999-01-01

    Expressions for the coefficient of performance and the cooling power of a thermionic refrigerator are derived taking into account the losses associated with thermal radiation and the need for a so-called passive conductor in the electrical circuit. Specific calculations are made for a thermionic device with a work function of 0.3 eV and it is shown that the performance is

  11. Finite-time optimum refrigeration cycles

    Microsoft Academic Search

    Mohand A. Ait-Alia

    1995-01-01

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

  12. Thermoelectric refrigerator having improved temperature stabilization means

    Microsoft Academic Search

    Falco

    1982-01-01

    A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement

  13. Generator cooling using heat pipes

    Microsoft Academic Search

    Bert de LEEUW; Harry Hagens; Brand van den S; Mart Grooten; FLA Ganzevles; Geld van der CWM; Kemenade van HP

    2006-01-01

    This paper presents the study of a heat pipe- equipped heat exchanger with two filling ratios of R134a 19 % and 59 %, respectively. The airflow rate varies from 0.4 to 2.0 kg\\/ s. The temperatures at the evaporator side of the heat pipe vary from 40 to 70 C and at the condenser part from 20 to 50 C.

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

    SciTech Connect

    Johnson, Francis

    2014-06-30

    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.

  15. Refrigeration options for the Advanced Light Source Superbend Dipole Magnets

    SciTech Connect

    Green, M.A.; Hoyer, E.H.; Schlueter, R.D.; Taylor, C.E.; Zbasnik, J.; Wang, S.T.

    1999-07-09

    The 1.9 GeV Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) produces photons with a critical energy of about 3.1 kev at each of its thirty-six 1.3 T gradient bending magnets. It is proposed that at three locations around the ring the conventional gradient bending magnets be replaced with superconducting bending magnets with a maximum field of 5.6 T. At the point where the photons are extracted, their critical energy will be about 12 keV. In the beam lines where the SuperBend superconducting magnets are installed, the X ray brightness at 20 keV will be increased over two orders of magnitude. This report describes three different refrigeration options for cooling the three SuperBend dipoles. The cooling options include: (1) liquid helium and liquid nitrogen cryogen cooling using stored liquids, (2) a central helium refrigerator (capacity 70 to 100 W) cooling all of the SuperBend magnets, (3) a Gifford McMahon (GM) cryocooler on each of the dipoles. This paper describes the technical and economic reasons for selecting a small GM cryocooler as the method for cooling the SuperBend dipoles on the LBNL Advanced Light Source.

  16. 63 FR 32044 - Protection of Stratospheric Ozone; Refrigerant Recycling; Substitute Refrigerants

    Federal Register 2010, 2011, 2012, 2013, 2014

    1998-06-11

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

  17. Impact of the Variable Refrigerant Volume Air Conditioning System on Building Energy Efficiency

    E-print Network

    Zhu, H.

    2006-01-01

    will be set up underground, and the cooling tower is laid out on the roof of the attached buildings. Program B: collective set-up of air conditioning system. Both the warm and cold source adopt direct-fired lithium-bromide absorption-type refrigerating... machine powered by city natural gas. The direct-fired lithium-bromide absorption-type refrigerating machine will be set up underground and the cooling tower is laid out on the roof of the attached buildings. Program C: air conditioning system...

  18. Optimization analysis of the performance of an irreversible Ericsson refrigeration cycle in the micro/nanoscale

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Wu, Guoxing; Fu, Yueming

    2011-10-01

    A general micro/nanoscaled model of the Ericsson refrigeration cycle is established in which finite-rate heat transfer, heat leak and regeneration time are taken into account. Based on the model, expressions for several important parameters such as the coefficient of performance (COP), cooling rate and power input are derived. By using numerical calculation and illustration, the influence of 'thermosize effects' on the performance of the Ericsson refrigeration cycle is discussed and evaluated. The optimal ranges of the COP, cooling rate and power input are determined. Furthermore, some special cases are discussed in detail. The results obtained here will provide theoretical guidance on designing a micro/nanoscaled Ericsson cycle device.

  19. Overview of Solid-State Thermoelectric Refrigerators and Possible Applications to On-Chip Thermal Management Thermoelectric cooling can be fairly easily added to conventional heat sinks and, with improved materials and processing, very effective hot-spot cooling can be achieved

    Microsoft Academic Search

    Jeff Sharp; Jim Bierschenk; Hylan B. Lyon

    The concept of thermal management in micro- electronic components is changing, and so is the potential for solid-state cooling to solve emerging problems. There is a qualitative change that differentiates the past from the future. We discuss past practices and future trends in the electronic cooling markets, setting the stage for an outline of designs and processes that provide new

  20. Purification and Liquefacttion of Neon Using a Helium Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Boeck, S.

    2010-04-01

    The cryogenic plant developed by Linde Kryotechnik is used to extract neon out of a crude gas flow coming from an air separation plant. The crude gas is cooled down by a two stage helium refrigeration process using the Linde Kryotechnik dynamic gas bearing turbines. After the first cooling stage, nitrogen is liquefied and separated from the crude gas. The Cryogenic adsorbers located at a temperature level below 80 K clean the crude gas from remaining nitrogen traces before the neon-helium mixture enters the final cooling stage. In the second cooling stage neon is liquefied and separated from the helium. The final product quality will be achieved within a rectification column at low pressure level.

  1. A theoretical study of new-style cool storage air-conditioning systems with high-temperature water

    Microsoft Academic Search

    Ze-Shao Chen; Xue-Gui Qi; Wen-Long Cheng; Peng Hu

    2006-01-01

    Cool storage technology is an effective means of shifting peak electrical loads by storing cooling capacity during off-peak time. A new-style cool storage scheme working with high-temperature water for air-conditioning is introduced in this paper. By supercooling refrigerant before being throttled with 238C water, the refrigerating output is raised and the water's sensible heat is converted to cool energy to

  2. Bipolar pulse field for magnetic refrigeration

    DOEpatents

    Lubell, Martin S. (Oak Ridge, TN)

    1994-01-01

    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.

  3. Thermoacoustic refrigerator for space applications

    NASA Astrophysics Data System (ADS)

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

    1993-10-01

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

  4. Magnetic refrigeration apparatus and method

    DOEpatents

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

    1984-01-01

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

  5. Simulation of refrigerant phase equilibria

    Microsoft Academic Search

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

    1997-01-01

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

  6. Testing and further development of a solar absorption cooling plant

    NASA Astrophysics Data System (ADS)

    Amannsberger, K.; Heckel, H.; Kreutmair, J.; Weber, K. H.

    1984-12-01

    Ammonia water absorption cooling units using the process heat of line-focusing solar collectors were developed and tested. Reduction of the evaporation temperature to minus 10 C; development of an air-cooled rectifying device for the refrigerant vapor; dry cooling of absorber and condenser by natural draft; refrigerating capacities of 14 to 10 kW which correspond to air temperatures of 25 to 40 C and 24 kW power consumption to heat the machine; auxiliary power requirement 450 W; full compatibility with changing heat input and air temperature, adaptation by automatic stabilization effects; and power optimization under changing boundary conditions by a simple regulating procedure independent of auxiliary power are achieved. The dynamic behavior of the directly linked collector-refrigeration machine system was determined. Operating conditions, market, and economic viability of solar cooling in third-world countries are described. Ice production procedures using absorption cooling units are demonstrated.

  7. Optimal performance of a thermoelectric refrigerator

    SciTech Connect

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

    1994-08-10

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

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

    SciTech Connect

    Nohtomi, Makoto; Katsuta, Masafumi

    1999-07-01

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

  9. UNIQUE METHOD FOR LIQUID NITROGEN PRECOOLING OF A PLATE FIN HEAT EXCHANGER IN A HELIUM REFRIGERATION CYCLE

    Microsoft Academic Search

    2004-01-01

    Precooling of helium by means of liquid nitrogen is one the oldest and most common process features used in helium refrigerators. The principal tasks are to permit a rapid cool down to 80 K of the plant, to increase the cooling power of the plant in low temperature operation and to increase the rate of pure liquid production. The advent

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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 3He. 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 3He. We show that the fork oscillator can be considered as self-calibrating in superfluid 3He at the crossover point from hydrodynamic into ballistic quasiparticle regime.

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

    SciTech Connect

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

    1990-11-01

    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{degree}F to 350{degree}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. 7 refs., 18 figs.

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

    SciTech Connect

    Todoshchenko, I., E-mail: todo@boojum.hut.fi; Kaikkonen, J.-P.; Hakonen, P. J.; Savin, A. [Low Temperature Laboratory, O.V. Lounasmaa Laboratory, Aalto University, FI-00076 AALTO (Finland); Blaauwgeers, R. [BlueFors Cryogenics Ltd, Arinatie 10, 00370 Helsinki (Finland)

    2014-08-01

    We demonstrate successful dry refrigeration of quantum fluids down to T = 0.16mK 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 {sup 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 = 4.4nW obtained in field of 35mT. For thermometry, we employed a quartz tuning fork immersed into liquid {sup 3}He. We show that the fork oscillator can be considered as self-calibrating in superfluid {sup 3}He at the crossover point from hydrodynamic into ballistic quasiparticle regime.

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

    PubMed

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

    2014-08-01

    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

  14. Study on scroll compressor behavior in case of liquid refrigerant injectio

    NASA Astrophysics Data System (ADS)

    Hirano, Takahisa; Hagimoto, Kiyoshi; Matsuda, Susumu

    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.

  15. Efficiency Calculations For a Magnetic Refrigerator Operating Between 2K and 10K

    NASA Technical Reports Server (NTRS)

    Helvensteijn, Ben P. M.; Kashani, A.; Kittel, P.; Sperans, Joel (Technical Monitor)

    1994-01-01

    An adiabatic demagnetization refrigerator (ADR) is being developed at NASA-Ames Research Center. The ADR will operate between 2 K and 10 K and will provide 50 mW of cooling at 2 K. The refrigerant in the ADR is Gadolinium Gallium Garnet (GGG). Absorption of heat at 2 K and heat rejection at 10 K in this fully static refrigerator is made possible by the incorporation of 2 K and 10 K heat switches. Physical layout and experimental results are presented in a parallel paper. The present paper discusses the thermal losses associated with components of the ADR as they occur in various parts of the refrigeration cycle. The results are summarized in terms of a prediction for the ADR efficiency.

  16. Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Wu, GuoXing

    2012-02-01

    A model of the irreversible regenerative Brayton refrigeration cycle working with paramagnetic materials is established, in which the regeneration problem in two constant-magnetic field processes and the irreversibility in two adiabatic processes are considered synthetically. Expressions for the COP, cooling rate, power input, the minimum ratio of the two magnetic fields, etc., are derived. It is found that the influence of the irreversibility and the regeneration on the main performance parameters of the magnetic Brayton refrigerator is remarkable. It is important that we have obtained several optimal criteria, which may provide some theoretical basis for the optimal design and operation of the Brayton refrigerator. The results obtained in the paper can provide some new theoretical information for the optimal design and performance improvement of real Brayton refrigerators.

  17. Parametric optimization of an irreversible magnetic Ericsson refrigerator with finite heat reservoirs

    NASA Astrophysics Data System (ADS)

    Ye, X. M.; Lin, G. X.; Chen, J. C.; Brck, E.

    2007-04-01

    An irreversible cycle model of magnetic Ericsson refrigerators is established, in which the finite heat capacities of external heat reservoirs, heat-transfer irreversibility, inherent regenerative losses, additional regenerative losses due to thermal resistances and irreversibility inside the magnetic working substances are taken into account. On the basis of the thermodynamic equations of paramagnetic materials, the performance characteristics of the magnetic Ericsson refrigeration cycle are investigated. By using the method of the optimal control theory, the optimal equations between the cooling load and the coefficient of performance and between the cooling load and the power input are derived. Furthermore, the maximum cooling load and the corresponding coefficient of performance, the minimum power input and the optimally operating temperatures of the cyclic working substance are obtained. The optimal operating region of the magnetic Ericsson refrigerator is determined. The results obtained here are closer to the performance characteristics of practical magnetic refrigerators with finite heat reservoirs than those in literature and are helpful to the optimal design and performance improvement of magnetic Ericsson refrigerators.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  19. SBIR Grant: ????????No-Vibration Agile Cryogenic Optical Refrigerator

    SciTech Connect

    Epstein, Richard

    2013-04-09

    Optical refrigeration is currently the only all-solid-state cryocooling technology that has been demonstrated. Optical cryocoolers are devices that use laser light to cool small crystal or glass cooling elements. The cooling element absorbs the laser light and reradiates it at higher energy, an example of anti-Stokes fluorescence. The dif-ference between the energy of the outgoing and incoming light comes from the thermal energy of the cooling element, which in turn becomes colder. Entitled ???????¢????????????????No-Vibration Agile Cryocoolers using Optical Refrigeration,???????¢??????????????? this Phase I proposal directly addressed the continued development of the optical refrigerator components necessary to transition this scientific breakthrough into National Nu-clear Security Administration (NNSA) sensor applications in line with the objectives of topic 50b. ThermoDynamic Films LLC (TDF), in collaboration with the University of New Mexico (UNM), cooled an optical-refrigerator cooling element comprised of an ytterbium-doped yttrium lithium fluoride (Yb:YLF) crystal from room tempera-ture to 123 K with about 2% efficiency. This is the world record in optical refrigera-tion and an important step toward revolutionizing cryogenic systems for sensor ap-plications. During this period, they also designed and analyzed the crucial elements of a prototype optical refrigerator including the thermal link that connects the cool-ing element with the load.

  20. Thermal links for the implementation of an optical refrigerator

    SciTech Connect

    Epsteiin, Richard I [Los Alamos National Laboratory; Greenfield, Scott R [Los Alamos National Laboratory; Parker, John [HARVEY MUDD COLLEGE; Mar, David [HARVEY MUDD GOLLEGE; Von Der Porten, Steven [HARVEY MUDD COLLEGE; Hankinson, John [HARVEY MUDD COLLEGE; Byram, Kevin [HARVEY MUDD COLLEGE; Lee, Chris [HARVEY MUDD COLLEGE; Mayeda, Kai [HARVEY MUDD COLLEGE; Haskell, Richard [HARVEY MUDD COLLEGE; Yang, Qimin [HARVEY MUDD COLLEGE

    2008-01-01

    Optical refrigeration has been demonstrated by several groups of researchers, but the cooling elements have not been thermally linked to realistic heat loads in ways that achieve the desired temperatures. The ideal thermal link will have minimal surface area, provide complete optical isolation for the load, and possess high thermal conductivity. We have designed thermal links that minimize the absorption of fluoresced photons by the heat load using multiple mirrors and geometric shapes including a hemisphere, a kinked waveguide, and a tapered waveguide. While total link performance is dependent on additional factors, we have observed net transmission of photons with the tapered link as low as 0.04%. Our optical tests have been performed with a surrogate source that operates at 625 nm and mimics the angular distribution of light emitted from the cooling element of the Los Alamos solid state optical refrigerator. We have confirmed the optical performance of our various link geometries with computer simulations using CODE V optical modeling software. In addition we have used the thermal modeling tool in COMSOL MULTIPHYSICS to investigate other heating factors that affect the thermal performance of the optical refrigerator. Assuming an ideal cooling element and a nonabsorptive dielectric trapping mirror, the three dominant heating factors are (1) absorption of fluoresced photons transmitted through the thermal link, (2) blackbody radiation from the surrounding environment, and (3) conductive heat transfer through mechanical supports. Modeling results show that a 1 cm{sup 3} load can be chilled to 107 K with a 100 W pump laser. We have used the simulated steady-state cooling temperatures of the heat load to compare link designs and system configurations.

  1. High frequency thermoacoustic refrigerator. Annual summary report, 1 June 1994-31 May 1995

    SciTech Connect

    Symko, O.G.

    1995-08-15

    Results are presented on the development of a high frequency thermoacoustic refrigerator and its performance. The device consists of a piezoelectric driver, operated around 5kHz, which is coupled to a cylindrical resonator containing air at 1 atmosphere as the compressible fluid. For sound levels of 155dB at the stack, a maximum T of 41 C was reached across a cotton wool stack 4mm long. A cooling power of 1.2 watt was achieved with a coefficient of performance of 3. This simple and lightweight refrigerator shows promise for cooling of small samples and electronic components. The performance of this type of refrigerator at high frequencies leads to high efficiency and power density. Research is aimed at improving its performance by optimizing some of the critical parameters such as the sound level and the thermal interface between stack and heat exchangers.

  2. Superinsulation in refrigerators and freezers

    SciTech Connect

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

    1998-02-01

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

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

    PubMed

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

    2014-11-17

    We investigated the effect of rare earth impurities on the cooling efficiency of Yb?: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

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

    NASA Astrophysics Data System (ADS)

    Basu, Sourish; Mueller, Erich J.

    2009-05-01

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

  5. Electrodynamic driver for the space thermoacoustic refrigerator (STAR). Master's thesis

    SciTech Connect

    Fitzpatrick, M.

    1988-03-01

    The objective of the STAR project is to test and space qualify a new continuous-cycle cryogenic refrigeration system for cooling of sensors and electronics which is based upon the newly discovered thermo-acoustic heat-pumping effect. The new refrigerator has no sliding seals, a cycle frequency of about 300 Hz, and uses acoustic resonance to enhance the overall power density and efficiency. This thesis is concerned specifically with the design and testing of the electrodynamic transducer, which is responsible for the electro-acoustic power conversion. A computer model of the driver/resonator system is presented along with the techniques for measurement of the electrical and mechanical parameters used as input for the model. A final driver design (including dimensional drawings) utilizing a modified JBL 2450J neodymium-iron-boron compression driver and associated leak-tight electrical feed-throughs, microphone, accelerometer, pressure gage, pressure housing, and resonator interface is provided.

  6. Superfluid orifice pulse tube refrigerator below 1 kelvin

    SciTech Connect

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

    1996-12-31

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

  7. Design of an adiabatic demagnetization refrigerator for studies in astrophysics

    NASA Technical Reports Server (NTRS)

    Castles, S.

    1983-01-01

    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.

  8. An optimized rotating helium-recondensing system using Roebuck refrigerators

    NASA Astrophysics Data System (ADS)

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

    1999-09-01

    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.

  9. Analysis of Transient Behavior of a Vapor Compression Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Fukushima, Toshihiko; Miyamoto, Seigo

    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.

  10. Energy Saving with Absorption Refrigeration Technologies

    E-print Network

    Davis, R. C.

    1984-01-01

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

  11. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  12. 46 CFR 154.702 - Refrigerated carriage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  13. A review of pulse tube refrigeration

    NASA Technical Reports Server (NTRS)

    Radebaugh, Ray

    1990-01-01

    This paper reviews the development of the three types of pulse tube refrigerators: basic, resonant, and orifice types. The principles of operation are given. It is shown that the pulse tube refrigerator is a variation of the Stirling-cycle refrigerator, where the moving displacer is substituted by a heat transfer mechanism or by an orifice to bring about the proper phase shifts between pressure and mass flow rate. A harmonic analysis with phasors is described which gives reasonable results for the refrigeration power, yet is simple enough to make clear the processes which give rise to the refrigeration. The efficiency and refrigeration power are compared with those of other refrigeration cycles. A brief review is given of the research being done at various laboratories on both one- and two-stage pulse tubes. A preliminary assessment of the role of pulse tube refrigerators is discussed.

  14. EVALUATION OF REFRIGERANT FROM MOBILE AIR CONDITIONERS

    EPA Science Inventory

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

  15. Commissioning and Operational Experience with 1 kW Class Helium Refrigerator\\/Liquefier for SST1

    Microsoft Academic Search

    C. P. Dhard; B. Sarkar; Ruchi Misra; A. K. Sahu; V. L. Tanna; J. Tank; P. Panchal; J. C. Patel; G. D. Phadke; Y. C. Saxena

    2004-01-01

    The helium refrigerator\\/liquefier (R\\/L) for the Steady State Super conducting Tokamak (SST-1) has been developed with very stringent specifications for the different operational modes. The total refrigeration capacity is 650 W at 4.5 K and liquefaction capacity of 200 l\\/h. A cold circulation pump is used for the forced flow cooling of 300 g\\/s supercritical helium (SHe) for the magnet

  16. New Regenerative Cycle for Vapor Compression Refrigeration

    SciTech Connect

    Mark J. Bergander

    2005-08-29

    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.

  17. Buy-back program recycles old refrigerators

    Microsoft Academic Search

    Musick

    1991-01-01

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

  18. Pressure-enthalpy diagrams for alternative refrigerants

    Microsoft Academic Search

    J. Chen; H. Kruse

    1996-01-01

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

  19. Optimum Refrigerant Selection for Low Temperature Engineering

    Microsoft Academic Search

    V. Mazur

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

  20. Measurement of acoustic velocity in the stack of a thermoacoustic refrigerator using particle image velocimetry

    Microsoft Academic Search

    Arganthal Berson; Marc Michard; Philippe Blanc-Benon

    2008-01-01

    Thermoacoustic refrigeration systems generate cooling power from a high-amplitude acoustic standing wave. There has recently\\u000a been a growing interest in this technology because of its simple and robust architecture and its use of environmentally safe\\u000a gases. With the prospect of commercialization, it is necessary to enhance the efficiency of thermoacoustic cooling systems\\u000a and more particularly of some of their components