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1

Two-phase cooling method using R134a refrigerant to cool power electronic devices  

Microsoft Academic Search

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

Jeremy B. Campbell; Leon M. Tolbert; Curt W. Ayers; Burak Ozpineci

2005-01-01

2

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

SciTech Connect

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

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

2007-01-01

3

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

SciTech Connect

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

Lowe, K.T.

2005-10-07

4

R-134a qualification -- industry refrigerator capillary data  

SciTech Connect

With the phaseout of R-12, the use of R-134a and polyolester (POE) oil became the preferred refrigerant/oil combination for the refrigerator appliance industry. Reliability data for this refrigerant/oil combination were minimal, and initial testing showed a propensity for the capillary tubes to clog with a variety of contaminants. A test was designed by an industry group to accelerate the process of contamination and capillary plugging. This paper presents capillary tube stress test data that were developed for this group by its member companies. This study investigated the relationship between capillary tube restriction levels and variables including compressor type, oil type, chlorine level, and moisture level. Analysis of the contaminants included a visual description, infrared spectroscopy, scanning electron microscope examination, and measurements of total chlorine content and noncondensable gas content of the refrigerant. Oil samples were measured for moisture level, dissolved iron, and total acid, and an infrared spectral analysis was performed.

DeVos, R. [Frigidaire Co., Greenville, MI (United States). Refrigerator Div.

1997-12-31

5

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

E-print Network

1 CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER for evaporation heat transfer coefficient of refrigerant R-134a flowing in a plate heat exchanger. Correlation heat exchanger are found to result in large discrepancies with their own experimental data

Kandlikar, Satish

6

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

NASA Astrophysics Data System (ADS)

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

Komatsubara, Takeo; Sunaga, Takasi; Takahasi, Yasuki

7

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

NASA Astrophysics Data System (ADS)

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

Takahashi, Hiroyuki; Saeki, Chikara; Koyama, Shigeru

8

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

SciTech Connect

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

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

2012-01-01

9

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

Microsoft Academic Search

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

T. S. Ravikumar; D. Mohan Lal

2009-01-01

10

Natural Refrigerant, Geothermal Heating & Cooling Solutions  

E-print Network

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

11

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

SciTech Connect

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)

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

12

Dimensional analysis on the evaporation and condensation of refrigerant R-134a in minichannel plate heat exchangers  

Microsoft Academic Search

Two-phase flow analysis for the evaporation and condensation of refrigerants within the minichannel plate heat exchangers is an area of ongoing research, as reported in the literatures reviewed in this article. The previous studies mostly correlated the two-phase heat transfer and pressure drop in these minichannel heat exchangers using theories and empirical correlations that had previously been established for two-phase

Amir Jokar; Mohammad H. Hosni; Steven J. Eckels

2006-01-01

13

R-134a emissions from vehicles.  

PubMed

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

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

2002-02-15

14

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

E-print Network

configuration. Second, experimental tests that included simultaneous operation with a mock automotive air-conditioner, and a radiator. However, with slight modification to existing air-conditioner (A/C) systems in automobiles with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles (HEVs

Tolbert, Leon M.

15

Refrigerant directly cooled capacitors  

DOEpatents

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

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

2007-09-11

16

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

Microsoft Academic Search

The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated electronics, is essential for the reliable operation of motors and power electronics. As part of a larger thermal management

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

17

648 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 43, NO. 3, MAY/JUNE 2007 Two-Phase Cooling Method Using the R134a  

E-print Network

that included a simultaneous operation with a mock automotive air-conditioner (A/C) system were performed, converters, and inverters for a specific application in hybrid-electric vehicles. The cooling method involves automotive A/C system has more than sufficient cooling capacity to cool a typical 30-kW trac- tion inverter

Tolbert, Leon M.

18

Infrared absorption spectrum of liquid cryogen R-134a  

NASA Astrophysics Data System (ADS)

Cryogen spray cooling (CSC) is an effective method to minimize epidermal damage during laser treatment of various cutaneous anomalies such as port wine stains, excess hair, and facial rhytides. Radiometric temperature measurements provide a noninvasive method to estimate the skin surface temperature. Since the infrared absorption spectrum of the cryogen film has remained unknown, assumptions for those values may lead to inaccurate temperature estimations. We have constructed several high-pressure infrared transparent cuvettes to determine the absorption coefficient of room temperature R-134a in liquid phase using Fourier Transform Infrared Spectroscopy (FTIR) in the 2.5 - 14 ?m spectral bandwidth. Results demonstrate that liquid R-134a has several absorption bands in the infrared, with those between 7 - 10.5 and 11.5 - 12.5 ?m being the most prominent. Additionally, the absorption coefficient at two common radiometric bands, 3 - 5 and 7 - 11 ?m differ by four orders of magnitude. Results of this study will lead to further improvements in interpreting radiometric temperature measurements when using CSC.

Pikkula, Brian M.; Guiwan, Edword; Chao, Edward; Anvari, Bahman

2004-07-01

19

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

Microsoft Academic Search

The performance of evaporator is of importance in cryogenic and refrigeration systems. In this paper, evaporative heat transfer and pressure drop characteristics of refrigerant R134a boiling inside a new geometry microfinned helically coiled tube is experimentally studied. Compared with corresponding smooth helically coiled tube, the heat transfer enhancement factors of microfinned helically coiled tube are up to 2.2 with the

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

2005-01-01

20

Effect of lubricant on spray evaporation heat transfer performance of R-134a and R-22 in tube bundles  

SciTech Connect

This study evaluates the effects of lubricant on spray evaporation heat transfer performance. Tests were conducted with refrigerant R-134a and triangular-pitch tube bundles made from enhanced-condensation, enhanced-boiling, low-finned, and plain-surface tubes. A 340-SUS polyol-ester (POE) oil was used for the R-134a testing because this lubricant is being integrated into industry for use with this refrigerant. Refrigerant was sprayed onto the tube bundles with low-pressure-drop, wide-angle nozzles located directly above the bundle. Collector testing was conducted with both R-134a and R-22 to determine the percentage of refrigerant contacting the tue bundle. It was found that small concentrations of the polyol-ester lubricant yielded significant improvement in the heat transfer performance of R-134a. The shell-side heat transfer coefficient was more dependent on lubricant concentration than on film-feed supply rate within the range of the respective parameters evaluated in this study. As expected, pure R-22 results show higher heat transfer coefficients than those obtained with pure R-134a at the same saturation temperature of 2.0 C (35.6 F).

Moeykens, S.A. [Trane Co., La Crosse, WI (United States); Pate, M.B. [Iowa State Univ., Ames, IA (United States)

1996-11-01

21

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

NASA Technical Reports Server (NTRS)

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.

Kvaternik, Ray

2006-01-01

22

Oil cooled, hermetic refrigerant compressor  

DOEpatents

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

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

1985-05-14

23

Magnetic refrigeration for maser amplifier cooling  

NASA Technical Reports Server (NTRS)

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

Johnson, D. L.

1982-01-01

24

Effect of Oils on Kinematic Viscosity of R134a  

NASA Astrophysics Data System (ADS)

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

Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

25

Elastic Metal Alloy Refrigerants: Thermoelastic Cooling  

SciTech Connect

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

None

2010-10-01

26

Potential Refrigerants for Power Electronics Cooling  

SciTech Connect

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

Starke, M.R.

2005-10-24

27

Motor Frame Cooling with Hot Liquid Refrigerant and Internal Liquid.  

National Technical Information Service (NTIS)

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

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

2005-01-01

28

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

Microsoft Academic Search

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

L. Kairouani; E. Nehdi

2006-01-01

29

Entanglement enhances cooling in microscopic quantum refrigerators  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

30

Cooling by heating: refrigeration powered by photons.  

PubMed

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

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

2012-03-23

31

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

32

Energy Efficient, Environmentally Friendly Refrigerants  

E-print Network

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

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

33

Compounds produced by motor burnouts of refrigeration systems  

SciTech Connect

The phase-out of chlorofluorocarbons has necessitated the introduction of alternate refrigerants. R22 (CF{sub 2}ClH), R134a (CF{sub 3}CH{sub 2}F), and R507 (50/50 CHF{sub 2}CF{sub 3}/CF{sub 3}CH{sub 3}) are newer fluids which are used in cooling systems. Recently, concern over the possible formation of toxic compounds during electrical arcing through these fluids has prompted us to identify their electrical breakdown products by electron ionization GC/MS. For example, it is known that perfluoroisobutylene (PFIB), which have an threshold limit value of 10 ppb (set by the American Conference of Government Industrial Hygienists), is produced from the thermal and electrical breakdown of some refrigerants. We have used specially designed test cells, equipped with electrodes, to simulate the electrical breakdown of R22, R134a, and R507 in refrigeration systems.

Koester, C.; Hawley-Fedder, R.; Foiles, L.

1995-05-24

34

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

NASA Astrophysics Data System (ADS)

Mixture models explicit in Helmholtz energy have been developed to calculate the thermodynamic properties of refrigerant mixtures containing R-32, R-125, R-134a, R143a, and R-152a. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the compressibility (or real fluid) contribution, and the contribution from mixing. The independent variables are the density, temperature, and composition. The model may be used to calculate the thermodynamic properties of mixtures, including dew and bubble point properties, within the experimental uncertainties of the available measured properties. It incorporates the most accurate equations of state available for each pure fluid. The estimated uncertainties of calculated properties are 0.1% in density and 0.5% in heat capacities and in the speed of sound. Calculated bubble point pressures have typical uncertainties of 0.5%.

Lemmon, Eric W.; Jacobsen, Richard T.

2004-06-01

35

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

Microsoft Academic Search

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

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

2006-01-01

36

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

SciTech Connect

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

Todd Salamon

2012-12-13

37

Keeping Cool With Solar-Powered Refrigeration  

NASA Technical Reports Server (NTRS)

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

2003-01-01

38

Slug-to-annular regime transitions in R-134a flowing through a vertical duct  

Microsoft Academic Search

Measurements of pressure gradient, local void fraction and interfacial velocity were taken in R-134a flowing through a vertical duct to characterize the transition from slug to fully developed annular flow. The measurements were taken in both heated and adiabatic conditions for two system pressures and two mass flow rates. The adiabatic data showed that droplet entrainment was enhanced at the

P. F Vassallo; T. A Trabold; R Kumar; D. M Considine

2001-01-01

39

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

NASA Technical Reports Server (NTRS)

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

Kvaternik, Raymond G.

2000-01-01

40

Annular flow of R-134a through a high aspect ratio duct: Local void fraction, droplet velocity and droplet size measurements  

SciTech Connect

Local measurements were made in annular flow of R-134a through a vertical duct. Using a gamma densitometer, hot-film anemometer and laser Doppler velocimeter, profiles of void fraction, liquid droplet frequency and droplet velocity were acquired across the narrow test section dimension. Based upon these results, data for liquid droplet size were obtained and compared to previous experimental results from the literature. These data are useful for developing an improved understanding of practical two-phase refrigerant flows, and for assessment of advanced two-fluid computer codes.

Trabold, T.A.; Kumar, R.; Vassallo, P.F. [Lockheed Martin Corp., Schenectady, NY (United States)

1998-11-01

41

Simulation research on scroll refrigeration compressor with external cooling  

Microsoft Academic Search

The compression process can approach the isothermal one when compressors are cooled in the compression process, and the compression work can be reduced. The paper presents a special external cooling structure for scroll refrigeration compressor. A mathematical model is established to simulate the compressor. All of boundary conditions in heat transfer model are set to coincide with the real operation

Shuaihui Sun; Yuanyang Zhao; Liansheng Li; Pengcheng Shu

2010-01-01

42

Cooling an electron gas using quantum dot based electronic refrigeration  

E-print Network

dots. Conventionally, low temperature measurements of 2DEGs are made by cooling the sample to 1.5 K with liquid Helium-4, to 300 mK with liquid Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron... of refrigerator is best suited to be used in conjunction with a dilution fridge or Helium-3 system to provide a final stage of cooling. The scheme was first investigated theoretically in 1993 by Edwards et al. but, to our knowledge, has never before been...

Prance, Jonathan Robert

2009-10-13

43

Vapor-liquid equilibria for R-22, R-134a, R-125, and R-32/125 with a polyol ester lubricant: Measurements and departure from ideality  

SciTech Connect

The effect of a polyol ester lubricant on equilibrium pressure, liquid density, and viscosity is presented for R-22, R-125, and R-134a at varying temperatures and concentrations. Preliminary vapor-liquid equilibrium (VLE) data and miscibility observations are also presented for an R-32/R-125 blend (50%/50%) with the ISO 68 polyol ester (POE). Real-gas behavior is modeled using the vapor-phase fugacity, and vapor pressure effects on liquid fugacities are taken into account with the Poynting effect. Positive, negative, and mixed deviations form the Lewis-Randall rule are observed in the activity coefficient behavior. Departures from ideality are related to molecular size differences, intermolecular forces in the mixture, and other factors. The data are discussed in the context of previous results for other refrigerants and thermodynamic modeling of refrigerant and oil mixtures.

Martz, W.L. [Ford Motor Co., Dearborn, MI (United States). Climate Control Div.; Burton, C.M.; Jacobi, A.M. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering

1996-11-01

44

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

SciTech Connect

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.

P Vassallo; K Keller

2004-12-13

45

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

NASA Astrophysics Data System (ADS)

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

Herman, C.; Travnicek, Z.

2006-04-01

46

Optimal design of gas adsorption refrigerators for cryogenic cooling  

NASA Technical Reports Server (NTRS)

The design of gas adsorption refrigerators used for cryogenic cooling in the temperature range of 4K to 120K was examined. The functional relationships among the power requirement for the refrigerator, the system mass, the cycle time and the operating conditions were derived. It was found that the precool temperature, the temperature dependent heat capacities and thermal conductivities, and pressure and temperature variations in the compressors have important impacts on the cooling performance. Optimal designs based on a minimum power criterion were performed for four different gas adsorption refrigerators and a multistage system. It is concluded that the estimates of the power required and the system mass are within manageable limits in various spacecraft environments.

Chan, C. K.

1983-01-01

47

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

SciTech Connect

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

None

2010-09-01

48

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

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

2014-07-01

49

Active Cooling for Downhole Instrumentation: Miniature Thermoacoustic Refrigerator.  

NASA Astrophysics Data System (ADS)

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.

Bennett, Gloria Adame

1991-02-01

50

Transient phenomena in a low cooling thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

51

Nucleate boiling performance of R-22, R-123, R-134a, R-410A, and R-407C on smooth and enhanced tubes  

SciTech Connect

Investigation of the nucleate boiling heat transfer on several commercially available enhanced tubes and smooth tubes was carried out in this study. The working refrigerants included R-22, R-123, R-134a, R-410A, and R-407C. Experiments were conducted at saturation temperatures of 0 C and 20 C. For the W-TX tube at a given saturation temperature, the heat transfer coefficients for R-410A are the largest and for R-123 are the lowest. For the highly structured surface, W-B tube, the heat transfer coefficients for R-22 and R-410A are comparable, while the heat transfer coefficients for R-407C are the lowest.

Wang, C.C.; Chang, Y.J. [Industrial Technology Research Inst., Hsinchu (Taiwan, Province of China). Energy and Research Labs.; Shieh, W.Y.; Yang, C.Y. [National Central Univ., Chung Li (Taiwan, Province of China). Dept. of Mechanical Engineering

1998-10-01

52

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

NASA Technical Reports Server (NTRS)

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

Britcliffe, Michael; Fernandez, Jose; Hanson, Theodore

2005-01-01

53

Open air–vapor compression refrigeration system for air conditioning and hot water cooled by cool water  

Microsoft Academic Search

This paper presents an open air–vapor 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 6°C. Its refrigeration depends mainly on both air and

Shaobo Hou; Huacong Li; Hefei Zhang

2007-01-01

54

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

SciTech Connect

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

Ling Zou; Barclay G. Jones

2012-11-01

55

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

E-print Network

Microjet array single-phase and flow boiling heat transfer with R134a Eric A. Browne a , Gregory J boiling a b s t r a c t An experimental study of single-phase and flow boiling heat transfer:6 6 Nud 6 128. Boiling experiments were conducted with liquid subcoolings of 10, 20, and 30 °C at jet

Peles, Yoav

56

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

SciTech Connect

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

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

2009-03-15

57

A closed cycle cascade Joule Thomson refrigerator for cooling Josephson junction magnetometers  

NASA Astrophysics Data System (ADS)

A closed cycle cascade Joule Thomson refrigerator designed to cool Josephson Junction magnetometers to liquid helium temperature is being developed. The refrigerator incorporates 4 stages of cooling using the working fluids CF4 and He. The high pressure gases are provided by a small compressor designed for this purpose. The upper stages have been operated and performance will be described.

Tward, E.; Sarwinski, R.

1985-05-01

58

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2011 CFR

...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

2011-07-01

59

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2010 CFR

...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

2010-07-01

60

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2013 CFR

...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

2013-07-01

61

40 CFR 82.36 - Approved refrigerant handling equipment.  

Code of Federal Regulations, 2012 CFR

...handling equipment. (a)(1) Refrigerant recycling equipment must be certified by the Administrator...J2788—HFC-134a (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile...

2012-07-01

62

Microjet array flow boiling with R134a and the effect of dissolved nitrogen Eric A. Browne, Michael K. Jensen, Yoav Peles  

E-print Network

Microjet array flow boiling with R134a and the effect of dissolved nitrogen Eric A. Browne, Michael online 16 November 2011 Keywords: Microjet Jet array Impingement Flow boiling a b s t r a c t An investigation of flow boiling with two arrays of microjets with R134a was conducted. Velocities of 4 and 7 m

Peles, Yoav

63

The 1- to 4-K refrigeration techniques for cooling masers on a beam waveguide antenna  

NASA Technical Reports Server (NTRS)

The status of technology is reported for various 1- to 4-K commercially available refrigeration systems capable of producing 1.5-K refrigeration to cool masers and superconducting cavity oscillators on the proposed beam waveguide antenna. The design requirements for the refrigeration system and the cryostat are presented. A continuously operating evaporation refrigerator that uses capillary tubing to provide a continuous, self-regulating flow of helium at approximately 1.5 K has been selected as the first refrigerator design for the beam waveguide antenna.

Johnson, D. L.

1986-01-01

64

Hydrocarbon Refrigerants for Car Air Conditioners  

Microsoft Academic Search

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

Ian Maclaine-cross; E. Leonardi

65

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

SciTech Connect

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

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

2000-07-01

66

A Photographic Study on Flow Boiling of R-134a in a Vertical Channel  

SciTech Connect

The behavior of near-wall bubbles in subcooled flow boiling has been investigated photographically for R134a flow in vertical, one-side heated and rectangular channels at mass fluxes of 0, 190, 1000 and 2000 kg/m{sup 2}.s and inlet subcooling condition of 8 deg. C under 7 bar(T{sub sat} 27 deg. C). Digital photographic techniques and high-speed camera are used for the visualization, which have significantly advanced for recent decades. Primary attention is given to the bubble coalescence phenomena and the structure of the near-wall bubble layer. At subcooled and low quality conditions, discrete attached bubbles, sliding bubbles, small coalesced bubbles and large coalesced bubbles or vapor clots are observed on the heated surface as the heat flux is increased from a low value. Particularly in beginning of vapor formation, vapor remnants below discrete bubble on the heating surface are clearly observed. Nucleation site density increases with the increases in heat flux and channel-averaged enthalpy, while discrete bubbles coalesce and form large bubbles, resulting in large vapor clots. Waves formed on the surface of the vapor clots are closely related to Helmholtz instability. At CHF occurrence it is also observed that wall bubble layer beneath large vapor clots is removed and large film boiling occurs. Through the present visual test, it is observed that wall bubble layer begins to develop with the onset of nucleate boiling (ONB) and to extinguish with the occurrence of the CHF. It could be considered that this layer made an important role of CHF mechanism macroscopically. However, there may be another structure beneath wall bubbles which supplies specific information on CHF from viewpoint of microstructure based upon the observation of the liquid sublayer beneath coalesced bubbles. Through this microscopic visualization, it may be suggested that the following flow structures characterize the flow boiling phenomena: (a) vapor remnants as a continuous source of bubbles, (b) liquid sublayer depleted with bubble formation if there is not new supply of liquid, and (c) vapor clot as an obstructer blanketing liquid supply to sublayer in high heat flux. (authors)

Bang, In Cheol; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Baek, Won-Pil [Korea Atomic Energy Research Institute, 150, Dukjin-dong, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

2002-07-01

67

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

Microsoft Academic Search

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

K. S. Ong

2010-01-01

68

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

Microsoft Academic Search

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

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

1997-01-01

69

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

SciTech Connect

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

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

2009-04-15

70

Thermodynamic performance analysis of gas-fired air-cooled adiabatic absorption refrigeration systems  

Microsoft Academic Search

In China, the application of small size gas-fired air-cooled absorption refrigeration systems as an alternative for electric compression air conditioning systems has shown broad prospects due to occurrence of electricity peak demand in Chinese big cities and lack of water resources. However, for conventional air-cooled absorption refrigeration systems, it is difficult to enhance the heat and mass transfer process in

L. Wang; G. M. Chen; Q. Wang; M. Zhong

2007-01-01

71

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

72

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

SciTech Connect

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

ANDREWS, J.W.

2001-04-01

73

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

SciTech Connect

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

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

2006-07-01

74

Surface Tension of Alternative Refrigerants  

NASA Astrophysics Data System (ADS)

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

Okada, Masaaki

75

A combined-cycle refrigeration system using ejector-cooling cycle as the bottom cycle  

Microsoft Academic Search

A combined-cycle refrigeration system (CCRS) that comprises a conventional refrigeration and air-conditioning system using mechanical compressor (RAC\\/MC) and an ejector-cooling cycle (EJC) is proposed and studied. The EJC is driven by the waste heat from the RAC\\/MC and acts as the bottom cycle of the RAC\\/MC. A system analysis shows that the COP of a CCRS is significantly higher than

B. J. Huang; V. A. Petrenko; J. M. Chang; C. P. Lin; S. S. Hu

2001-01-01

76

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

NASA Astrophysics Data System (ADS)

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

Sato, Tomoaki; Takaishi, Yoshinori; Oguchi, Kosei

77

Sample Loading and Accelerated Cooling of Cryogen-free Dilution Refrigerators  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

78

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

SciTech Connect

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

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

2007-01-01

79

Performance and Safety of LPG Refrigerants  

Microsoft Academic Search

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

I. L. Maclaine-cross; E. Leonardi

80

Defrost gas conditioner for air cooled reverse cycle defrost refrigeration system  

SciTech Connect

This patent describes a reverse cycle defrost refrigeration system having a compressor, an air cooled condenser and evaporator means having surfaces for forming ice thereon during a freezing cycle and arranged to discharge the ice therefrom during a defrost cycle, conduit means for conducting gaseous refrigeration from the compressor to the condenser to be condensed to liquid refrigerant in the condenser and conduit means for conducting the liquid refrigerant to the evaporator means during the freezing cycle, defrost cycle means including a defrost conduit means having defrost solenoid valve connected to the condenser hot gas supply form the compressor and a discharge conduit connected thereto and to the evaporator means to supply hot gaseous refrigerant to the evaporator means during the defrost cycle. The defrost conduit means is connected to the condenser for releasing flash gas from the condenser to the evaporator at the time the defrost solenoid valve opens. The improvement comprises means for conditioning warm defrost gaseous refrigerant which passes back through the discharge conduit to the defrost solenoid valve and the evaporator means at the beginning of the defrost cycle from carrying slugs of liquid refrigerant that may be in the condenser into the discharge conduit and evaporator means and compressor including a liquid separator surge tank and an inlet conduit connected to the top of the surge tank.

Morris, W.F. Jr.

1988-01-19

81

Cooling of superconducting devices by liquid storage and refrigeration unit  

DOEpatents

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

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

2013-08-20

82

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

SciTech Connect

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

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

2014-01-01

83

Construction of a dilution refrigerator cooled scanning force microscope  

NASA Astrophysics Data System (ADS)

We present a scanning force microscope that operates in a dilution refrigerator at temperatures of about 100 mK. We use tuning fork sensors for scanning gate experiments on mesoscopic semiconductor nanostructures. Slip-stick motors allow sample coarse-positioning at base temperature. The construction, thermal anchoring, and a procedure to optimize the settings of the phase-locked loop that we use for sensor control are discussed in detail. We present low-temperature topographic and scanning gate images as examples of successful operation.

Gildemeister, A. E.; Ihn, T.; Barengo, C.; Studerus, P.; Ensslin, K.

2007-01-01

84

Construction of a dilution refrigerator cooled scanning force microscope.  

PubMed

We present a scanning force microscope that operates in a dilution refrigerator at temperatures of about 100 mK. We use tuning fork sensors for scanning gate experiments on mesoscopic semiconductor nanostructures. Slip-stick motors allow sample coarse-positioning at base temperature. The construction, thermal anchoring, and a procedure to optimize the settings of the phase-locked loop that we use for sensor control are discussed in detail. We present low-temperature topographic and scanning gate images as examples of successful operation. PMID:17503925

Gildemeister, A E; Ihn, T; Barengo, C; Studerus, P; Ensslin, K

2007-01-01

85

THERMODYNAMIC EVALUATION OF FIVE ALTERNATIVE REFRIGERANTS IN VAPOR-COMPRESSION CYCLES  

EPA Science Inventory

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

86

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

87

Study of a Vuilleumier cycle cryogenic refrigerator for detector cooling on the limb scanning infrared radiometer  

NASA Technical Reports Server (NTRS)

A program to detect and monitor the presence of trace constituents in the earth's atmosphere by using the Limb Scanning Infrared Radiometer (LSIR) is reported. The LSIR, which makes radiometric measurements of the earth's limb radiance profile from a space platform, contains a detector assembly that must be cooled to a temperature of 65 + or - 2 K. The feasibility of cooling the NASA-type detector package with Vuilleumier (VM) cryogenic refrigerator was investigated to develop a preliminary conceptual design of a VM refrigerator that is compatible with a flight-type LSIR instrument. The scope of the LSIR program consists of analytical and design work to establish the size, weight, power consumption, interface requirements, and other important characteristics of a cryogenic cooler that would meet the requirements of the LSIR. The cryogenic cooling requirements under the conditions that NASA specified were defined. Following this, a parametric performance analysis was performed to define the interrelationships between refrigeration characteristics and mission requirements. This effort led to the selection of an optimum refrigerator design for the LSIR mission.

Russo, S. C.

1976-01-01

88

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

SciTech Connect

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

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

2010-03-31

89

A closed-cycle refrigerator for cooling maser amplifiers below 4 Kelvin  

NASA Technical Reports Server (NTRS)

A helium refrigerator utilizing the Gifford-McMahon/Joule-Thomson (GM/JT) cycle was designed and tested to demonstrate the feasibility of using small closed-cycle refrigerators as an alternative to batch-filled cryostats for operating temperatures below 4 K. The systems could be used to cool low-noise microwave maser amplifiers located in large parabolic antennas. These antennas tilt vertically, making conventional liquid-filled dewars difficult to use. The system could also be used for a non-tilting beam waveguide antenna to reduce the helium consumption of a liquid helium cryostat. The prototype system is adjustable to provide 700 mW of cooling at 2.5 K to 3 W at 4.3 K. Performance of the unit is not significantly affected by physical orientation. The volume occupied by the refrigerator is less than 0.1 cu m. Two JT expansion stages are used to maximize cooling capacity per unit mass flow. The heat exchangers were designed to produce minimum pressure drop in the return gas stream. Pressure drop for the entire JT return circuit is less than 5 kpa at a mass flow of 0.06 g/sec when operating at 2.5 K.

Britcliffe, M.

1989-01-01

90

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

SciTech Connect

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

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

2012-12-01

91

R&D on The Cooling Systems Using Natural Refrigerants  

NASA Astrophysics Data System (ADS)

The use of waste heat of low temperatures is an important problem from the environmental considerations. Notice that adsorption cycles have a distinct advantage over other systems of their ability to produce cooling by using low waste heat as 60 to 80°C and also being absolutely benign for the environment. However the present available adsorption chillers are still heavier and larger in size. Hence their compactness and cost reduction as well as higher efficiency are urgent tasks for wider use. This review discusses recent development on adsorption heat pumps as well as forthcoming applications. The sources are mainly papers and discussions at the IEA Annex 24 Workshop in Turin, Italy (1999), FOA6 (Fundamental of Adsorption) Conference in Presquile de Giens, France (1998) and ISHPC (International Sorption Heat Pump Conference) in Munich, Germany (1999).

Yanagi, Hideharu

92

Commissioning report of the MuCool 5 Tesla solenoid coupled with helium refrigerator  

SciTech Connect

MuCool 5T solenoid was successfully cooled down and operated coupled with MTA 'Brown' refrigerator. The system performed as designed with substantial performance margin. All process alarms and interlocks, as well as ODH and fire alarms, were active and performed as designed. The cooldown of the refrigerator started from warm conditions and took 44 hours to accumulate liquid helium level and solenoid temperature below 5K. Average liquid nitrogen consumption for the refrigerator precool and solenoid shield was measured as 20 gal/hr (including boil-off). Helium losses were small (below 30 scfh). The system was stable and with sufficient margin of performance and ran stably without wet expansion engine. Quench response demonstrated proper operation of the relieving devices and pointed to necessity of improving tightness of the relieving manifolds. Boil-off test demonstrated average heat load of 3 Watts for the unpowered solenoid. The solenoid can stay up to 48 hours cold and minimally filled if the nitrogen shield is maintained. A list of improvements includes commencing into operations the second helium compressor and completion of improvements and tune-ups for system efficiency.

Geynisman, Michael; /Fermilab

2010-05-01

93

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

SciTech Connect

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

Aroonrat, Kanit; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

2011-01-15

94

Conductively cooled Nb sub 3 Sn magnet system for a magnetic refrigerator  

SciTech Connect

A Nb{sub 3}Sn magnet system for use in a magnetic refrigerator has been developed and tested. The system incorporates four asymmetric windings arranged as two Helmholtz pairs to produce two profiled field regions required for a Carnot cycle. System components are cooled by conductive heat transfer to enable eventual operation in vacuum without liquid helium. Design features include low resistance joints and superconducting interconnecting buses for low ohmic losses in the persistent mode. The magnets are produced by the wind-and-react method on iron forms, followed by epoxy impregnation. In this paper the system requirements and design are described in further detail, and test results are presented.

Rowe, J.R.; Hertel, J.A.; Barclay, J.A.; Cross, C.R.; Trueblood, J.R.; Hill, D.D. (Astronautics Technology Center, Madison, WI (United States))

1991-03-01

95

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

96

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

NASA Technical Reports Server (NTRS)

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

Miller, Franklin K.

2012-01-01

97

Miscibility comparison for three refrigerant mixtures and four component refrigerants  

SciTech Connect

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

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

1999-07-01

98

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

E-print Network

Cooling towers, because of their seeming simplicity, are usually orphans of the facilities operation. We are all aware that cooling towers are the step-children of the chemical process plant, electric power generating station, and refrigeration...

Burger, R.

99

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

NASA Astrophysics Data System (ADS)

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

Tzabar, N.

2014-11-01

100

4 K to 20 K rotational-cooling magnetic refrigerator capable of 1-mW to >1-W operation  

SciTech Connect

The low-temperature, magnetic entropy of certain single-crystal paramagnetic materials, such as DyPO/sub 4/, changes dramatically as the crystal rotates in a magnetic field. A new magnetic refrigerator design based on the anisotropic nature of such materials is presented. The key advantages of the rotational-cooling concept are (1) a single, rotary motion is required, (2) magnetic field shaping is not a problem because the entire working material is in a constant field, and (3) the refrigerator can be smaller than comparable magnetic refrigerators because the working material is entirely inside the magnet at all times. The main disadvantage of the rotational-cooling concept is that small-dimension single crystals are required.

Barclay, J.A.

1980-02-01

101

High-power operation of 1cm laser diode bars on funryu heat sink cooled by fluorinated-refrigerant  

NASA Astrophysics Data System (ADS)

We investigated the properties of fluorinated refrigerants for high-power laser diode bars mounted on a funryu heat sink. The thermal conductivity of fluorinated refrigerants is about ten times lower than that of water, but they are less corrosive to funryu heat sinks. Using 3M's "Fluorinet" FC77 and "Novec" HFE-7300 and comparing them with water as refrigerants, we developed a new fluorinated refrigerant cooling device that is suitable for removing heat from highpower LDs and LD modules. This device achieved CW light-output power from a 1-cm LD bar equivalent to that for a cooling device using ion-exchange water. With HFE-7300 as the refrigerant, we achieved over 100 W of output power at a drive current of CW 120 A and over 1.5 kW for a stacked-LD module operated at a constant current of 55 A in continuous-wave (CW) mode. High-power LD bars subjected to lifetime testing under these conditions have been successfully running for over 15,000 consecutive hours.

Oishi, Satoru; Miyajima, Hirofumi; Suzuki, Noriyasu; Natsume, Tomoyuki; Fujita, Toru; Nishida, Koji; Kurino, Hironobu; Okamoto, Ryusuke; Kageyama, Nobuto; Suzuki, Nobutaka; Uchiyama, Takayuki; Kan, Hirofumi

2009-02-01

102

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

NASA Astrophysics Data System (ADS)

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

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

2004-12-01

103

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

SciTech Connect

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

None

2010-09-01

104

Thermotile Refrigerators  

NASA Technical Reports Server (NTRS)

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

Park, Brian V.

1994-01-01

105

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

NASA Astrophysics Data System (ADS)

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

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

2002-05-01

106

Cooling the ANL SC heavy-ion linac with two refrigerators in parallel. Preprint Paper G-26  

SciTech Connect

The Argonne Superconducting Heavy-Ion Linac consists of a series of niobium accelerating resonators grouped in cryostats. The resonators are cooled by a forced-circulation flow of liquid helium directly from a CTI Model 1400 refrigerator through a low-loss distribution line. Helium entering each cryostat is condensed to near liquid saturation by heat exchange with the colder, lower pressure return stream. As more resonators and cryostats have been added to the linac over the past few years, it has been necessary to increase the cooling capacity of the system without increasing the flow of helium through the outgoing primary side of the distribution line and the resonators. This has been accomplished by coupling the first operational CTI Model 2800 turbo-expander refrigerator in parallel with the Model 1400 in such a way as to avoid major modifications in the helium distribution system.

Nixon, J.M.; Bollinger, L.M.

1981-01-01

107

Cooling the ANL SC heavy-ion linac with two refrigerators in parallel. Preprint Paper G-26  

Microsoft Academic Search

The Argonne Superconducting Heavy-Ion Linac consists of a series of niobium accelerating resonators grouped in cryostats. The resonators are cooled by a forced-circulation flow of liquid helium directly from a CTI Model 1400 refrigerator through a low-loss distribution line. Helium entering each cryostat is condensed to near liquid saturation by heat exchange with the colder, lower pressure return stream. As

J. M. Nixon; L. M. Bollinger

1981-01-01

108

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

Microsoft Academic Search

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

Ammar Bahman

2011-01-01

109

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

110

ARTI Refrigerant Database  

NASA Astrophysics Data System (ADS)

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

Cain, J. M.

1993-04-01

111

ARTI Refrigerant Database  

NASA Astrophysics Data System (ADS)

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

Calm, J. M.

1993-11-01

112

ARTI Refrigerant Database  

SciTech Connect

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

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

1993-04-30

113

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

114

page 1 of 4 TkF Vrmeteknik Refrigeration / Kylteknik  

E-print Network

liquid) enthalphy h = hf = 63 kJ/kg at 15°C #12;page 3 of 4 207. A person wants to buy a heat pump that uses outside air heat for heating a small house. It should give 50 kJ/h heat. A shop offers a heat pump devices. 205. A vapour-compression system that uses refrigerant R-134a must be tested to determine optimal

Zevenhoven, Ron

115

Refrigeration for Cryogenic Sensors  

NASA Technical Reports Server (NTRS)

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

Gasser, M. G. (editor)

1983-01-01

116

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

SciTech Connect

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

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

1980-03-01

117

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

E-print Network

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

Miller, Franklin K., 1970-

2005-01-01

118

Experimental study on automotive cooling and heating air conditioning system using CO 2 as a refrigerant  

Microsoft Academic Search

Recently, as one of the countermeasures against the global warming and energy conservation problems, natural refrigerants such as CO2 are now paid attention as substitutes for HFCs in automotive air conditioning systems. Also, in recent years because the heat release from the eco-car's engine decreases, there is a problem that the present automotive heating air conditioning system cannot provide sufficient

Tomoichiro Tamura; Yuuichi Yakumaru; Fumitoshi Nishiwaki

2005-01-01

119

A Study on Bubble Departure and Bubble Lift-Off in Sub-Cooled Nucleate Boiling Flows  

SciTech Connect

This research examines bubble departure and bubble lift-off phenomena under subcooled nucleate boiling condition, using a high fidelity digital imaging apparatus. Refrigerant R- 134a is chosen as a simulant fluid due to its merits of having smaller surface tension, reduced latent heat, and lower boiling temperature than water. Images at frame rates up to 4000 frames/s were obtained with varying experimental parameters e.g. pressure, inlet sub-cooled level, and flow rate, etc., showing characteristics of bubble behavior under different conditions. Bubble size and position information was calculated via Canny's algorithm for edge detection and Fitzgibbon's algorithm for ellipse fitting. Bubble departure and lift-off radiuses were obtained and compared with existing bubble forces and detachment models proposed by Thorncroft et al., with good agreement observed. (authors)

Wu, Wen; Chen, Peipei; Jones, Barclay G. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign Urbana, IL 61801 (United States); Newell, Ty A. [Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign Urbana, IL 61801 (United States)

2006-07-01

120

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

SciTech Connect

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

Not Available

1986-04-30

121

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

NASA Astrophysics Data System (ADS)

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

Takei, Toshitaka; Saito, Kiyoshi; Kawai, Sunao

122

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

E-print Network

towers, because of their seeming simplicity, are usually orphans of the facilities operation. We are all aware that cooling towers are the step-children of the chemical process plant, electric power generating station, and refrigeration system..., TX, June 19-20, 1990 Figure S. cellular fill Case History III The Power Generating Plant. The question of rebuilding large capacity exiting cooling towers for industrial power plants to modernize them to provide necessary additional capacity...

Burger, R.

123

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

SciTech Connect

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

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

1999-07-01

124

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

SciTech Connect

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

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

1999-10-01

125

Boiling heat transfer enhancement with carbon nanotubes for refrigerants used in building air-conditioning  

Microsoft Academic Search

In this study, the effect of carbon nanotubes (CNTs) on nucleate boiling heat transfer is investigated. Two halocarbon refrigerants of R123 and R134a for building chillers were used as working fluids and 1.0vol.% of CNTs was added to them to examine the heat transfer enhancement with CNTs. The experimental apparatus was composed of a stainless steel vessel and a 152.0mm

Ki-Jung Park; Dongsoo Jung

2007-01-01

126

A progress report on using bolometers cooled by adiabatic demagnetization refrigeration  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

127

Status Of Sorption Cryogenic Refrigeration  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.

1988-01-01

128

Operation of a TES microcalorimeter cooled by a compact liquid-helium-free 3He- 4He dilution refrigerator directly coupled to a Gifford-McMahon cooler  

NASA Astrophysics Data System (ADS)

A superconducting transition edge thermosensor (TES) microcalorimeter was irradiated with LX-ray photons emitted by an 241Am source maintained at an operating temperature of 120 mK using a compact liquid-helium-free 3He- 4He dilution refrigerator directly coupled to a Gifford-McMahon (GM) cooler. The first and second stages of the GM cooler were directly coupled to the first and second pre-cool heat exchangers of a stick shaped dilution unit through copper plates in a vacuum chamber. The helium-free dilution refrigerator provided a cooling power of 20 ?W at 100 mK. Detection signals of LX-ray photons emitted by the 241Am source were observed by operating the TES microcalorimeter in a severe noise environment induced by the mechanical vibrations of the GM cooler.

Umeno, T.; Maehata, K.; Ishibashi, K.; Kamioka, Y.; Yoshida, S.; Takasaki, K.; Tanaka, K.

2010-05-01

129

Fluorescent refrigeration  

DOEpatents

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

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

1995-01-01

130

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

SciTech Connect

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

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

2002-08-30

131

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

E-print Network

-power dissipation have become a long-term IC reliability concern in diverse applications such as high (see Fig. 3). These refrigerators can be grown directly on a silicon substrate and they can be used

132

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)

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.

Richards, Paul L.

2005-01-01

133

Fluorescent refrigeration  

DOEpatents

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

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

1995-09-05

134

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

135

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

E-print Network

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...

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

2006-01-01

136

Multilayer Thermionic Refrigeration  

Microsoft Academic Search

A new method of refrigeration is proposed. Efficient cooling is obtained by thermionic emission of electrons over Schottky barriers between metals and semiconductors. Since the barriers have to be thin, each barrier can have only a small temperature difference (âĽ1 K) . Macroscopic cooling is obtained with a multilayer device. The same device is also an efficient generator of electrical

G. D. Mahan; L. M. Woods

1998-01-01

137

Toxicity Data to Determine Refrigerant Concentration Limits  

SciTech Connect

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

Calm, James M.

2000-09-30

138

On the Influence of Heating Surface Structure on Bubble Detachment in Sub-Cooled Nucleate Boiling Flows  

SciTech Connect

This research examines the influence of heating surface structure on bubble detachment, which includes bubble departure and bubble lift-off, under sub-cooled nucleate boiling condition, in order to obtain better understanding to the bubble dynamics on horizontal flat heat exchangers. Refrigerant R-134a is chosen as a simulant fluid due to its merits of having smaller surface tension, reduced latent heat, and lower boiling temperature than water. Experiments were run with varying experimental parameters e.g. pressure, inlet sub-cooled level, and flow rate, etc. High speed digital images at frame rates up to 4000 frames/s were obtained, showing characteristics of bubble movement. Bubble radius and center coordinates were calculated via Canny's algorithm for edge detection and Fitzgibbon's algorithm for ellipse fitting. Results were compared against the model proposed by Klausner et al. for prediction of bubble detachment sizes. Good overall agreement was shown, with several minor modifications and suggestions made to the assumptions of the model. (authors)

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

2006-07-01

139

Refrigeration system  

SciTech Connect

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

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

1986-11-11

140

Chemical and thermal stability of refrigerant-lubricant mixtures with metals  

NASA Astrophysics Data System (ADS)

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

Huttenlocher, D. F.

1992-10-01

141

Stirling Refrigerator  

NASA Astrophysics Data System (ADS)

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

Kagawa, Noboru

142

Space helium refrigerator  

NASA Astrophysics Data System (ADS)

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

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

1981-08-01

143

Alternative refrigerants and refrigeration cycles for domestic refrigerators  

SciTech Connect

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

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

1992-12-01

144

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

between the Re-cooling Temperature of the CRM and the Ambient Temperature and their Absolute Frequencies 5. Conclusion and Outlook In terms of primary energy consumption and with the underlying operating parameters first DC and if demand exceeds... ? Methodology ? Results ? Outlook ? Conclusion 2 The System RCP:?Re?cooling plant AC:?Absorption?chiller CC:?Compressor chiller CHP:?Combined heat and power?plant 3 RCP 2400 kW CC 665 kW AC 710 kW CHP Buffer Buffer Consumer8?C 95?C 27?C 27...

Uhrhan, S.; Gerber, A.

2012-01-01

145

Magnetocaloric refrigeration near room temperature (invited)  

Microsoft Academic Search

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

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

2007-01-01

146

The high-capacity, spaceborne, Vuilleumier refrigerator  

NASA Astrophysics Data System (ADS)

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

Doody, R. D.

1980-01-01

147

NICE3: Industrial Refrigeration System  

SciTech Connect

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

Simon, P.

1999-09-29

148

Adsorption Refrigeration System  

SciTech Connect

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

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

2011-01-01

149

Malone refrigeration  

SciTech Connect

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

Swift, G.W.

1993-01-01

150

Self-regulated energy saving refrigeration circuit  

SciTech Connect

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

Aleksandrow, J.

1985-07-23

151

Cascade Joule-Thomson refrigerators  

NASA Astrophysics Data System (ADS)

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

Tward, E.; Steyert, W. A.

1983-12-01

152

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

SciTech Connect

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

Gunsel, Selda; Pozebanchuk, Michael

1999-04-01

153

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

154

Variable Refrigerant Flow HVAC  

E-print Network

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

Jones, S.

2013-01-01

155

Microminiature Refrigeration  

NASA Astrophysics Data System (ADS)

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

Little, W. A.

2008-03-01

156

Cryogenic refrigeration apparatus  

DOEpatents

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

Crunkleton, James A. (Cambridge, MA)

1992-01-01

157

Cryogenic refrigeration apparatus  

DOEpatents

A technique for producing a cold environment in a refrigerant system in which input fluid from a compressor at a first temperature is introduced into an input channel of the system and is pre-cooled to a second temperature for supply to one of at least two stages of the system, and to a third temperature for supply to another stage thereof. The temperatures at such stages are reduced to fourth and fifth temperatures below the second and third temperatures, respectively. Fluid at the fourth temperature from the one stage is returned through the input channel to the compressor and fluid at the fifth temperature from the other stage is returned to the compressor through an output channel so that pre-cooling of the input fluid to the one stage occurs by regenerative cooling and counterflow cooling and pre-cooling of the input fluid to the other stage occurs primarily by counterflow cooling. 6 figs.

Crunkleton, J.A.

1992-03-31

158

Thermoacoustic refrigeration  

NASA Technical Reports Server (NTRS)

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

Garrett, Steven L.; Hofler, Thomas J.

1991-01-01

159

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

E-print Network

thermionic (HIT) micro-refrigerator has been proposed as one of possible on-chip thermal management solutions based on heterostruc- ture integrated thermionic (HIT) micro-refrigerator has been proposed as one are based on a superlattice-enhanced thermionic emission process. In this process, hot electrons from

160

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

E-print Network

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

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

1996-01-01

161

Malone refrigeration  

SciTech Connect

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

Swift, G.W.

1993-06-01

162

Thermoelectric refrigerator having improved temperature stabilization means  

DOEpatents

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

Falco, Charles M. (Woodridge, IL)

1982-01-01

163

Multistation refrigeration system  

NASA Technical Reports Server (NTRS)

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

Wiebe, E. R. (inventor)

1978-01-01

164

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

SciTech Connect

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

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

1997-12-31

165

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

NASA Astrophysics Data System (ADS)

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

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

166

Superfluid thermodynamic cycle refrigerator  

DOEpatents

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

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

1992-12-22

167

Superfluid thermodynamic cycle refrigerator  

DOEpatents

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

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

1992-01-01

168

Sorption cryogenic refrigeration - Status and future  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.

1988-01-01

169

Refrigerator temperature and defrost control  

SciTech Connect

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

Janke, D.E.

1987-05-12

170

Refrigeration Circuit Employed New Refrigerant  

NASA Astrophysics Data System (ADS)

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

Ohnishi, Haruo

171

Feasibility Study of an Automotive Thermoacoustic Refrigerator  

Microsoft Academic Search

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

Luke Zoontjens; Carl Howard; Anthony Zander; Ben Cazzolato

2005-01-01

172

Brownian Refrigerator C. Van den Broeck  

E-print Network

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

Kawai, Ryoichi

173

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

SciTech Connect

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

Calm, J.M.

1993-11-28

174

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

NASA Technical Reports Server (NTRS)

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

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

1956-01-01

175

Adsorption refrigeration research in Shanghai Jiao Tong University  

Microsoft Academic Search

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

R. Z. Wang

2001-01-01

176

Helium dilution refrigeration system  

DOEpatents

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

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

1988-09-13

177

Helium dilution refrigeration system  

DOEpatents

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

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

1988-01-01

178

Intra-molecular refrigeration in enzymes  

E-print Network

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

Hans J. Briegel; Sandu Popescu

2009-12-14

179

Refrigeration Showcases  

NASA Technical Reports Server (NTRS)

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

1997-01-01

180

Compact acoustic refrigerator  

DOEpatents

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

Bennett, G.A.

1992-11-24

181

Compact acoustic refrigerator  

DOEpatents

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

Bennett, Gloria A. (Los Alamos, NM)

1992-01-01

182

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

PubMed

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

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

2003-07-01

183

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

SciTech Connect

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

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

1999-05-01

184

Magnetic Refrigeration: Perfecting the Process  

NSDL National Science Digital Library

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

Baumgold, Ben

2005-01-01

185

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

NASA Astrophysics Data System (ADS)

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

Sendil Kumar, D.; Elansezhian, R.

2014-03-01

186

Multilayer thermionic refrigerator and generator  

Microsoft Academic Search

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

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

1998-01-01

187

Magnetocaloric refrigeration near room temperature (invited)  

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

188

Solar-powered cooling system  

DOEpatents

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.

Farmer, Joseph C

2013-12-24

189

Refrigeration Servicing.  

ERIC Educational Resources Information Center

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

Hamilton, Donald L.; And Others

190

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

E-print Network

conditioning, cooling towers, food cooling and freezing (4) Heat pumps, heat pipes, special ww.sgisland.o p p (~ 240 K) for household and food applications ­ down to -200°C (~ 70 K) for industrial gas processing

Zevenhoven, Ron

191

He dilution refrigerator  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

192

Pot-in-Pot Refrigeration  

NSDL National Science Digital Library

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

Omsi

2004-01-01

193

Wheel-type magnetic refrigerator  

DOEpatents

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

Barclay, J.A.

1983-10-11

194

Wheel-type magnetic refrigerator  

DOEpatents

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

Barclay, J.A.

1982-01-20

195

Wheel-type magnetic refrigerator  

DOEpatents

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

Barclay, John A. (Los Alamos, NM)

1983-01-01

196

Refrigerant piping  

SciTech Connect

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

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

1996-10-01

197

Magnetic Refrigeration Development  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

198

Cooling Towers, Energy Conservation Strategies  

E-print Network

Cooling towers, because of their seeming simplicity, are usually orphans of the facilities operation. We are all aware that cooling towers are the step-children of the chemical process plant, electric power generating station, and refrigeration...

Burger, R.

1983-01-01

199

Mixed refrigerant Joule-Thomson sorption cryocoolers  

NASA Astrophysics Data System (ADS)

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

Tzabar, Nir; Grossman, Gershon

2014-01-01

200

Thermoelectric refrigerator having improved temperature-stabilization means  

SciTech Connect

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

Falco, C.M.

1981-07-29

201

Ground Loops for Heat Pumps and Refrigeration  

E-print Network

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

Braud, H. J.

1986-01-01

202

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

E-print Network

growth, consumption Cooling and freezing of food gives important alternatives for other food, etc. Special considerations in food freezing and cooling are, for l h f i d bl i ( d ) d Picture: Ă?BFood products /3 Important for freezing is the rate: too slow freezing gives large ice crystalsg g g y

Zevenhoven, Ron

203

40 CFR 749.68 - Hexavalent chromium-based water treatment chemicals in cooling systems.  

Code of Federal Regulations, 2010 CFR

...transfers heat from air handling units or refrigeration equipment to a refrigeration machine, or chiller. (3) Closed cooling...heating, ventilation, and air conditioning or refrigeration systems. (5) Container means...

2010-07-01

204

Magnetic refrigeration: the promise and the problems  

SciTech Connect

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

Barclay, J.A.

1984-01-01

205

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

SciTech Connect

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

None

2010-10-01

206

Mathematical analysis of a Vuilleumier refrigerator.  

NASA Technical Reports Server (NTRS)

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

Sherman, A.

1971-01-01

207

REACH. Refrigeration Units.  

ERIC Educational Resources Information Center

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

Snow, Rufus; And Others

208

ARTI refrigerant database  

SciTech Connect

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

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

1999-01-01

209

ARTI refrigerant database  

SciTech Connect

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

Calm, J.M.

1996-11-15

210

ARTI refrigerant database  

SciTech Connect

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

Calm, J.M.

1996-07-01

211

ARTI refrigerant database  

SciTech Connect

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

Calm, J.M.

1996-01-15

212

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

NASA Astrophysics Data System (ADS)

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

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

213

New Design of Neon Refrigerator for Hts Power Machines  

Microsoft Academic Search

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

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

2010-01-01

214

Magnetic refrigeration—towards room-temperature applications  

Microsoft Academic Search

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

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

2003-01-01

215

IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems  

SciTech Connect

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

Baxter, VAN

2003-05-19

216

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

E-print Network

- compression cycle Sources for "cheap heat" could be waste heat from power generation or steamp g plants processes: i l ffi iexpensive, spacy, low efficiency, requires large cooling towers for waste heat, not common. Ch h b l bl Cheap heat must be available. Energy balance & COPR : Picture: Ă?B98 L With Ts = 120

Zevenhoven, Ron

217

Thermodynamic Properties for A Drop-in Refrigerant R-SP34E  

NASA Astrophysics Data System (ADS)

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

Kayukawa, Yohei; Hondo, Takashi; Watanabe, Koichi

218

Development of a solar-powered passive ejector cooling system  

Microsoft Academic Search

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

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

2001-01-01

219

Availability of refrigerants for heat pumps in Europe  

E-print Network

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

Oak Ridge National Laboratory

220

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

E-print Network

/pressure combination, unlike freezing / melting, and i l t h t ff t (H >> H ) finvolves greater heat effects-cooling a bit beyond (3) reduces the risk of "flashing" i h For each step: (Qin - Qout) + (Win -Wout) + 8 isothermal 2-3 and 4-1: isentropic maximum thermal efficiency th = 1 ­ QH/QL Picture: �B98 th H L

Zevenhoven, Ron

221

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

E-print Network

10 kW 1 MWCapacity 10°C (Semi-)hermetic i ti 1-stage open 1-stage open rature°C -20 reciprocating (source: S90) Absorption systemsAbsorption systems 100 W 10 kW 1 MWCapacity 10°C ature°C NH / H O H Li applications ° ot.gif Typical ranges -35 ~ +5°C; cooling capacity W mages

Zevenhoven, Ron

222

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

Microsoft Academic Search

A pilot plant project was undertaken to develop a central refrigeration compressor station capable of providing the necessary cooling to a network of nine independently-controlled environmental test chambers operating at temperatures of minus 85 F to 350 F. Design features of the central two-stage (cascade) vapor compression refrigeration system are described. Computer control of the central refrigeration station is a

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

1990-01-01

223

Development of a low noise 10 KJ-T refrigeration system  

Microsoft Academic Search

Work has continued on the evaluation of the pneumatic compressor system which will be used to demonstrate (1) operating lifetime of the refrigerator gas compressor under development and (2) compressor-refrigerator system performance. Work to improve the cooling capacity of the refrigerator at 20 K by using more efficient heat exchanger designs has continued. While operation down to 20 K was

Robert L. Paugh

1991-01-01

224

A review on Mn based materials for magnetic refrigeration: Structure and properties  

Microsoft Academic Search

Magnetic refrigeration employing magnetically ordered materials is a relatively novel technique, differing in some respects from magnetic cooling by means of adiabatic demagnetization of paramagnetic substances. Magnetic refrigeration has been known for more than a century and is based on the magnetocaloric effect. It has received new impetus recently because it has several advantages over vapor-compression refrigeration. In the last

E. Brück; O. Tegus; D. T. Cam Thanh; Nguyen T. Trung; K. H. J. Buschow

2008-01-01

225

Shuttle kit freezer refrigeration unit conceptual design  

NASA Technical Reports Server (NTRS)

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

Copeland, R. J.

1975-01-01

226

Applications Tests of Energy Efficient, Environmentally Friendly Refrigerants  

E-print Network

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...

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

227

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

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

228

New Rules for Refrigerants.  

ERIC Educational Resources Information Center

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

Jackson, Robert

1999-01-01

229

Cooling Towers--Energy Conservation Strategies  

E-print Network

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...

Matson, J.

230

A rotary magnetic refrigerator for superfluid helium production  

NASA Astrophysics Data System (ADS)

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

Hakuraku, Y.; Ogata, H.

1986-11-01

231

Auto defrost refrigerator  

SciTech Connect

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

Schulze, J.L.

1988-05-03

232

An electrocaloric refrigerator without external regenerator  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

233

Development of Magnetic Refrigerator  

NASA Astrophysics Data System (ADS)

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

Ogiwara, Hiroyasu; Nakagome, Hideki; Kuriyama, Tohru

234

Improving the Efficiency of Your Process Cooling System  

E-print Network

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...

Baker, R.

2005-01-01

235

Self-actuating heat switches for redundant refrigeration systems  

NASA Technical Reports Server (NTRS)

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

Chan, Chung K. (inventor)

1988-01-01

236

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

SciTech Connect

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

Leigh, R.; Andrews, J.

1995-11-01

237

Regenerative sorption compressors for cryogenic refrigeration  

NASA Technical Reports Server (NTRS)

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

Bard, Steven; Jones, Jack A.

1990-01-01

238

Magnetically suspended Stirling cryogenic space refrigerator Status report  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

239

Study of the Physics of Droplet Impingement Cooling  

E-print Network

which are currently subject of active research, we include: spray cooling, jet cooling, single and multipledroplet cooling, vapor compres- sion refrigeration, and thermosyphons. All of these options can achieve heat fluxes several times higher than... which are currently subject of active research, we include: spray cooling, jet cooling, single and multipledroplet cooling, vapor compres- sion refrigeration, and thermosyphons. All of these options can achieve heat fluxes several times higher than...

Soriano, Guillermo Enrique

2012-07-16

240

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

NASA Astrophysics Data System (ADS)

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

Fischer, S. K.

241

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

ERIC Educational Resources Information Center

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

DiMercurio, C.

1981-01-01

242

Dilution Refrigerator for Nuclear Refrigeration and Cryogenic Thermometry Studies  

NASA Astrophysics Data System (ADS)

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

Nakagawa, Hisashi; Hata, Tohru

2014-07-01

243

A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus  

SciTech Connect

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

Raustad, Richard A. [Florida Solar Energy Center

2013-01-01

244

Quantum heat engines and refrigerators: continuous devices.  

PubMed

Quantum thermodynamics supplies a consistent description of quantum heat engines and refrigerators up to a single few-level system coupled to the environment. Once the environment is split into three (a hot, cold, and work reservoir), a heat engine can operate. The device converts the positive gain into power, with the gain obtained from population inversion between the components of the device. Reversing the operation transforms the device into a quantum refrigerator. The quantum tricycle, a device connected by three external leads to three heat reservoirs, is used as a template for engines and refrigerators. The equation of motion for the heat currents and power can be derived from first principles. Only a global description of the coupling of the device to the reservoirs is consistent with the first and second laws of thermodynamics. Optimization of the devices leads to a balanced set of parameters in which the couplings to the three reservoirs are of the same order and the external driving field is in resonance. When analyzing refrigerators, one needs to devote special attention to a dynamical version of the third law of thermodynamics. Bounds on the rate of cooling when Tc?0 are obtained by optimizing the cooling current. All refrigerators as Tc?0 show universal behavior. The dynamical version of the third law imposes restrictions on the scaling as Tc?0 of the relaxation rate ?c and heat capacity cV of the cold bath. PMID:24689798

Kosloff, Ronnie; Levy, Amikam

2014-01-01

245

Quantum Heat Engines and Refrigerators: Continuous Devices  

NASA Astrophysics Data System (ADS)

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

Kosloff, Ronnie; Levy, Amikam

2014-04-01

246

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

Microsoft Academic Search

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

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

2009-01-01

247

Magnetic refrigerator for hydrogen liquefaction  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

248

Electronic refrigeration at the quantum limit.  

PubMed

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

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

2009-05-22

249

Cooling system, for power generating plant, using split or partitioned heat exchanger  

SciTech Connect

Apparatus and method comprising a base cooling system using a refrigeration cycle, a peak-shaving system using a secondary cooling liquid, and a regeneration system for the peak-shaving system secondary cooling liquid. A split or partitioned heat exchanger alternately condenses only the refrigerant in the base cooling system or it condenses that refrigerant and a refrigerant used to cool hot secondary cooling liquid. The apparatus can be used in power generating plants with the split heat exchanger located in a cooling tower.

Husain, M.; Lai, B.; Schmitt, R.L.

1982-02-16

250

New Design of Neon Refrigerator for Hts Power Machines  

NASA Astrophysics Data System (ADS)

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.

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

2010-04-01

251

Adaptive defrost control for a refrigerator  

SciTech Connect

A control is described for a refrigeration device having cooling apparatus including an evaporator, defrosting apparatus for removing frost from the evaporator and means for energizing the defrosting apparatus at the end of a cooling cycle to initiate a defrost cycle, comprising: detecting means for detecting the rate of change of evaporator temperature during a defrosting cycle; determining means for determining the length of time the rate of change of evaporator temperature remains at substantially zero; and establishing means for establishing the duration of a subsequent cooling cycle in dependence upon the determined length of time.

Janke, D.E.; Linstromberg, W.J.

1987-09-01

252

Neon turbo-Brayton cycle refrigerator for HTS power machines  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

253

ARTI refrigerant database  

SciTech Connect

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

Calm, J.M.

1997-02-01

254

ARTI refrigerant database  

SciTech Connect

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

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

1998-08-01

255

Waste Heat Recovery from Refrigeration  

E-print Network

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

Jackson, H. Z.

1982-01-01

256

Chemically assisted mechanical refrigeration process  

DOEpatents

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

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

1987-01-01

257

Chemically assisted mechanical refrigeration process  

DOEpatents

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

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

1987-01-01

258

Chemically assisted mechanical refrigeration process  

DOEpatents

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

Vobach, A.R.

1987-11-24

259

Chemically assisted mechanical refrigeration process  

DOEpatents

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

Vobach, A.R.

1987-06-23

260

Evaporative system for water and beverage refrigeration in hot countries  

E-print Network

beverages cool in hot arid regions. The system uses a flow of air that flows around a water container, whichEvaporative system for water and beverage refrigeration in hot countries A Saleh1 and MA Al-Nimr2 1 is wrapped in a wet fabric. The air before being introduced could be dehumidified and cooled to capture more

261

Load leveling on industrial refrigeration systems  

NASA Astrophysics Data System (ADS)

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

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

1982-01-01

262

Numerical simulation and experimental validation of vapour compression refrigeration systems. Special emphasis on CO 2 trans-critical cycles  

Microsoft Academic Search

A numerical and experimental comparative study of a carbon dioxide trans-critical refrigerating system and a conventional sub-critical refrigerating cycle is presented. Attention is focussed not only on the whole refrigeration cycle, but also on the behaviour of the hermetic reciprocating compressors used in these systems. The comparative cases presented have been specially designed for small cooling capacity units with an

J. Rigola; G. Raush; C. D. Pérez-Segarra; A. Oliva

2005-01-01

263

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

SciTech Connect

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

Not Available

1994-08-01

264

Thermoacoustically driven refrigerator with double thermoacoustic-Stirling cycles  

NASA Astrophysics Data System (ADS)

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

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

2006-02-01

265

Method of operating a transport refrigeration system  

SciTech Connect

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

Howland, L.L.

1988-01-26

266

Theory of cascade refrigeration  

NASA Astrophysics Data System (ADS)

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

Quack, Hans H.

2012-06-01

267

Influence of Oil on Refrigerant Evaporator Performance  

NASA Astrophysics Data System (ADS)

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

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

268

Application of Cryocoolers to a Vintage Dilution Refrigerator  

SciTech Connect

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

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

2011-06-06

269

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

270

Experimental Investigation of a Traveling-wave Refrigerator  

NASA Astrophysics Data System (ADS)

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

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

2006-04-01

271

Device applications of cryogenic optical refrigeration  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

272

Selected Vuilleumier refrigerator performance characteristics  

NASA Technical Reports Server (NTRS)

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

Sherman, A.

1973-01-01

273

Magnetic refrigeration for space applications  

SciTech Connect

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

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

1980-01-01

274

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

DOEpatents

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

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

1997-01-01

275

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

DOEpatents

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

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

1997-04-22

276

Evaporative cooling workshop. Final technical report  

Microsoft Academic Search

With conventional refrigeration, room air is recirculated through the refrigeration unit. The air is chilled perhaps 20 degrees or more below room temperature and then blown into the rooms at low velocity and volume. This cold air mixes with the rest of the warm air in the room - cooling it without creating strong air currents. If you happen to

Mumma

1982-01-01

277

New technologies for refrigeration without CFC's  

NASA Astrophysics Data System (ADS)

Today the appliance industry and other cooling industries are facing the double challenge of eliminating environmentally harmful CFC's 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 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 CFC's 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 CFC's, and reduce the consumption of electricity.

Swift, G. W.

1992-07-01

278

Thermal Characteristics of Chemical Refrigerating Apparatus using Silica-Gel/ Inorganic-Salt-Solution Pair  

NASA Astrophysics Data System (ADS)

This report deals with chemical refrigerating apparatus using silica-gel / inorganic-salt-solution pair. Experiments are conducted by changing concentration of inorganic-salt solution and adsorbent / refrigerant pair. The following results are obtained. (1) The temperature of refrigerant in evaporator is lowered as decrease of inorganic-salt-solution concentration. (2) The available salt-concentration range as refrigerant are gained by supercooling in restricted temperature range lower than solidification temperature of solution. (3)Difference of minimum temperature among cooled refrigerants are little in low concentration region. (4)In concentration lower than about10wt%, refrigerants supercool and solidify suddenly. Accordingly these salt-solutions are not available in these region as refrigerants.

Yanadori, Michio; Watabe, Yoshihito

279

Thermoacoustic engines and refrigerators  

SciTech Connect

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

Swift, G.

1996-12-31

280

Quantum-enhanced absorption refrigerators  

E-print Network

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

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

2014-01-01

281

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material  

DOEpatents

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

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

1987-01-01

282

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material  

DOEpatents

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

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

1986-04-03

283

High-Pressure Phase Equilibria of Ionic Liquids and Compressed Gases for Applications in Reactions and Absorption Refrigeration  

E-print Network

and two compressed gases: carbon dioxide (CO2) and 1,1,1,2-Tetrafluoroethane (R-134a). The global phase behavior and phase equilibria are measured in the temperature range from approximately 0?C to 105?C and pressure up to 330 bar. Binary systems of R-134a...

Ren, Wei

2009-12-29

284

Cooling system for superconducting magnet  

DOEpatents

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

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

1998-01-01

285

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2012 CFR

...Air Source Unitary Heat Pump Equipment and certified...unitary cooling systems with rated capacity...1-1996, Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances, and...Direct refrigerating systems serving any...

2012-04-01

286

Quantum optics: Cool computation, hot bits  

NASA Astrophysics Data System (ADS)

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

Lloyd, Seth

2014-02-01

287

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2011 CFR

...Air Source Unitary Heat Pump Equipment and certified...unitary cooling systems with rated capacity...1-1996, Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances, and...Direct refrigerating systems serving any...

2011-04-01

288

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2010 CFR

...Air Source Unitary Heat Pump Equipment and certified...unitary cooling systems with rated capacity...1-1996, Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances, and...Direct refrigerating systems serving any...

2010-04-01

289

24 CFR 3280.714 - Appliances, cooling.  

Code of Federal Regulations, 2013 CFR

...Air Source Unitary Heat Pump Equipment and certified...unitary cooling systems with rated capacity...1-1996, Gas Fired, Heat Activated, Air Conditioning and Heat Pump Appliances, and...Direct refrigerating systems serving any...

2013-04-01

290

Analysis of performance of heat exchangers used in practical micro miniature refrigerators  

Microsoft Academic Search

Micro miniature refrigerators are employed to cool small infra-red sensors and other electronic devices in a number of applications. In a micro miniature refrigerator the heat exchanger, expansion valve and evaporator are all machined on a thin glass or stainless steel sheet (typically about 1 mm thick). Unlike normal heat exchangers, the volume of the flow channels of the heat

S. Pradeep Narayanan; G. Venkatarathnam

1999-01-01

291

The optimum design of air cycle refrigeration system with high pressure water separation  

Microsoft Academic Search

A mathematical model is developed for designing air-cycle refrigeration systems with known performance parameters and functional characteristics. The refrigeration systems considered are designed with high-pressure water separation, and attention is given to the attendant problems of freezing at the condenser outlet and design strategies for the cooling turbine. The design point selected for the model is at the maximum flight

Yu Wang; Xiu-Gan Yuan

1992-01-01

292

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

ERIC Educational Resources Information Center

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

Alberta Advanced Education and Technology, 2012

2012-01-01

293

Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander  

E-print Network

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

Bahrami, Majid

294

Minimal self-contained quantum refrigeration machine based on four quantum dots.  

PubMed

We present a theoretical study of an electronic quantum refrigerator based on four quantum dots arranged in a square configuration, in contact with as many thermal reservoirs. We show that the system implements the minimal mechanism for acting as a self-contained quantum refrigerator, by demonstrating heat extraction from the coldest reservoir and the cooling of the nearby quantum dot. PMID:23829751

Venturelli, Davide; Fazio, Rosario; Giovannetti, Vittorio

2013-06-21

295

46 CFR 154.702 - Refrigerated carriage.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

296

Determination of a vapor compression refrigeration system refrigerant charge  

NASA Astrophysics Data System (ADS)

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

Yang, Chun-Xin; Dang, Chao-Bin

1995-09-01

297

Analysis and characterization of thermoelectric module and heat exchanger performance in a hybrid system cooling application  

Microsoft Academic Search

A thermoelectric chiller is a potential replacement for subambient refrigeration for electronics cooling applications, where the reliance on vapor compression refrigeration results in risk of cooling failure due to the mechanical nature of the compressor and electronic expansion valve. Another benefit of a thermoelectric chiller is that controllable cooling of the electronic component can be achieved regardless of ambient conditions,

L. A. Campbell; R. E. Simons

2011-01-01

298

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

NASA Astrophysics Data System (ADS)

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

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

1990-11-01

299

Algor mortis: an erroneous measurement following postmortem refrigeration.  

PubMed

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

Wardak, Khalil S; Cina, Stephen J

2011-09-01

300

Save with Hybrid Refrigeration  

E-print Network

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

Chung, C. W.

301

Helium dilution refrigeration  

E-print Network

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

McKee, Thomas Raymond

2012-06-07

302

Absorption refrigeration and heat pump system  

SciTech Connect

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

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

1988-01-19

303

Low-temperature magnetic refrigerator  

DOEpatents

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

Barclay, J.A.

1983-05-26

304

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...

305

COLD STORAGE DESIGN REFRIGERATION EQUIPMENT  

E-print Network

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

306

Optimal Sequencing of Central Refrigeration Equipment in an Industrial Plant  

E-print Network

. The primary cooling medium used throughout the plant is 42'~ chilled water. It is produced by four chillers totaling 4200 tons of refrigeration. The chilled water is pumped through the chillers and then through the plant's chilled water supply and return... lines by five chilled water primary pumps totaling 625 horsepower and two ohilled water booster pumps totaling 200 horsepower. Heat liberated by the chillers' vapor compression cycles is rejected to the atmosphere by five cooling towers totaling...

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

1986-01-01

307

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

NASA Astrophysics Data System (ADS)

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

Akasaka, Ryo

308

Thermodynamics of adiabatic laser processes: Optical heaters and refrigerators  

Microsoft Academic Search

A thermodynamic operating condition for lasing (in the presence of losses) is derived. This provides a lower bound for the required density of systems in the emitting level. Efficient cooling enables one to reduce this bound. The results are shown to be a particular application of the thermodynamic limitations on heating of refrigeration achieved via luminescence. Department of Physical Chemistry.

O. Kafri; R. D. Levine

1974-01-01

309

REFRIGERATION PROCESSES BELOW 25 K WITH TURBO EXPANDERS  

Microsoft Academic Search

BS>The losses produced in low-temperature installations are considered, ; and the most advantageous types of construction for refrigerating circuits with ; several expansion turbines are determined. The turbines used in Sulzer circuits ; are radial with one stage resting on oil bearings. One turbine with gas bearings ; is described. The cooling installa-tion construction for the hydrogen bubble ; chamber

Trepp

1962-01-01

310

Stirling Air Conditioner for Compact Cooling  

SciTech Connect

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

None

2010-09-01

311

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

312

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

313

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

314

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

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

2014-01-01

315

Multilayer thermionic refrigeration  

Microsoft Academic Search

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

G. D. Mahan

1999-01-01

316

Improved cryogenic refrigeration system  

NASA Technical Reports Server (NTRS)

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

Higa, W. H.

1967-01-01

317

Fundamentals of Refrigeration.  

ERIC Educational Resources Information Center

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

Sutliff, Ronald D.; And Others

318

Solar Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

319

Plant Site Refrigeration Upgrade  

E-print Network

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

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

320

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

E-print Network

on climate change drive the need to look at new cooling and refrigeration options that are sustainable, and there will not be any onsite registration because of security requirements at NIST. Registration is now open-Members: $575. Moving towards Sustainability Oct. 29-30, National Institute of Standards & Technology

Ginzel, Matthew

321

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

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

322

Dilution refrigeration for space applications  

NASA Technical Reports Server (NTRS)

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

Israelsson, U. E.; Petrac, D.

1990-01-01

323

Step piston pulse tube refrigerator  

NASA Astrophysics Data System (ADS)

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

Zhu, Shaowei

2014-11-01

324

Experimental results on a low-temperature magnetic refrigerator  

NASA Astrophysics Data System (ADS)

A Carnot-cycle magnetic refrigerator has been designed, built, and tested in the temperature range of approx. 4 K to approx. 15 K. Gadolinium gallium garnet in the rim of a wheel is the refrigerant. The wheel rim rotates through a gap between two superconducting Helmholtz coils that produce a magnetic field of up to 6 T. Helium gas is used as the heat-transfer fluid in the hot and cold regions of the wheel. The refrigerator performance has been measured in an open-cycle flow system because no suitable low-temperature helium gas pumps were available for closed loop circulation of helium gas. Over one watt of cooling power with a temperature span of several degrees was achieved. At low frequencies the cooling power and temperature changes of the refrigerator match the entropy-temperature data used in the design. Problems associated with friction and gas mixing limit the performance at frequencies above about 0.1 Hz. Separate friction measurements suggest that gas flow control is the dominant problem that needs to be solved before significant improvement in refrigerator operation can be expected. The present measured efficiency is about 20% of Carnot if the drive motor efficiency is ignored. With friction and other losses in the drive motor mechanism, the overall efficiency is approx. 1% of Carnot.

Barclay, J. A.; Stewart, W. F.; Overton, W. C.; Candler, R. J.; Harkleroad, O. D.

1985-06-01

325

Experimental results on a low-temperature magnetic refrigerator  

SciTech Connect

A Carnot-cycle magnetic refrigerator has been designed, built, and tested in the temperature range of approx.4 K to approx.15 K. Gadolinium gallium garnet in the rim of a wheel is the refrigerant. The wheel rim rotates through a gap between two superconducting Helmholtz coils that produce a magnetic field of up to 6 T. Helium gas is used as the heat-transfer fluid in the hot and cold regions of the wheel. The refrigerator performance has been measured in an open-cycle flow system because no suitable low-temperature helium gas pumps were available for closed loop circulation of helium gas. Over one watt of cooling power with a temperature span of several degrees was achieved. At low frequencies the cooling power and temperature changes of the refrigerator match the entropy-temperature data used in the design. Problems associated with friction and gas mixing limit the performance at frequencies above about 0.1 Hz. Separate friction measurements suggest that gas flow control is the dominant problem that needs to be solved before significant improvement in refrigerator operation can be expected. The present measured efficiency is about 20% of Carnot if the drive motor efficiency is ignored. With friction and other losses in the drive motor mechanism, the overall efficiency is approx.1% of Carnot.

Barclay, J.A.; Stewart, W.F.; Overton, W.C.; Candler, R.J.; Harkleroad, O.D.

1985-01-01

326

Magnetic refrigeration apparatus with heat pipes  

DOEpatents

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

Barclay, J.A.; Prenger, F.C. Jr.

1985-10-25

327

Magnetic refrigeration apparatus with heat pipes  

DOEpatents

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

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

1987-01-01

328

An Experimental Study on Thermal Energy Storage Based Reverse Cycle Defrosting Method Using Subcooling Energy of Refrigerant for Air Source Heat Pump: Characteristics of Thermal Energy Storage Operation  

Microsoft Academic Search

the introduction introduction of the the system of thermal energy storage torage (TES) based reverse cycle defrosting method using sub-cooling energy of refrigerant for air Source heat eat p pump (ASHP) is given firstly. And And then the the characteristic of TES TES using sub-cooling energy of refrigerant in in heating is experimentally researched. The results results show that that

Dong Jiankai; Qu Minglu; Jiang Yiqiang; Yao Yang; Deng Shiming; Wang Honglei

2011-01-01

329

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

330

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

331

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

332

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

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

2014-01-01

333

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

Code of Federal Regulations, 2010 CFR

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

2010-01-01

334

Stimulated radiative laser cooling  

E-print Network

Building a refrigerator based on the conversion of heat into optical energy is an ongoing engineering challenge. Under well-defined conditions, spontaneous anti-Stokes fluorescence of a dopant material in a host matrix is capable of lowering the host temperature. The fluorescence is conveying away a part of the thermal energy stored in the vibrational oscillations of the host lattice. In particular, applying this principle to the cooling of (solid-state) lasers opens up many potential device applications, especially in the domain of high-power lasers. In this paper, an alternative optical cooling scheme is outlined, leading to radiative cooling of solid-state lasers. It is based on converting the thermal energy stored in the host, into optical energy by means of a stimulated nonlinear process, rather than a spontaneous process. This should lead to better cooling efficiencies and a higher potential of applying the principle for device applications.

Muys, Peter

2007-01-01

335

Refrigeration-type dehumidifying system with rotary dehumidifier  

SciTech Connect

A dehumidifying system is described comprising: a rotary dehumidifier radially defining a dehumidifying chamber, a defrost chamber and a cooling chamber; a refrigerant circulator having a compressor circulating a refrigerant for cooling a primary cooler and a secondary cooler respectively cooling a dehumidifying air to lower its dew point below the ice point of water and the rotary dehumidifier; a dehumidifying-air circulator having an air loop duct communicated with a suction port of a building interior, and a defrost-air supplier having a suction duct communicated with an outside environment, an air blower blowing a warm air as heated by a defrost-air heater formed on the suction duct into the defrost chamber of the dehumidifier, and a discharge duct for outwardly discharging the water vapor as carried by the air from the defrost chamber.

Lin, W.F.

1988-04-19

336

Semimetal cascades - Solid state precursors to spacecraft slush hydrogen refrigerators  

NASA Astrophysics Data System (ADS)

The design of an energy conversion system for the refrigeration of stored propellant during a spacecraft mission represents a challenging problem. The utilization of cascaded semimetal elements for the development of solid-state propellant refrigerators for interplanetary spacecraft is, in this connection, considered. The present investigation gives attention to a hypothetical cooling device to show the viability of a thermomaganetic cooling system and to give direction to semimetals development. Problems of propellant storage heat absorption during a 405-day Mars mission are discussed. It is concluded that solid-state refregeration is the most reliable and light-weight means for thermal control of the stored hydrogen. The use of a cascaded series of thermomagnetic cooling elements could maintain a slush hydrogen temperature of 13.6 K, 0.2 K below the triple point. Attention is given to figure of merit improvement goals, semimetal cascade staging requirements, and aspects of magnetic enhancement and other improvements with high-temperature superconductors.

Schalla, C. A.

337

Analysis of cooldown performance for ISABELLE helium refrigerator  

SciTech Connect

The ISABELLE refrigerator was designed to provide cooling for 1000 superconducting magnets. It has the dual duty of providing cooling at steady-state operating conditions and to cooldown massive magnets from ambient temperature. During the cooldown, tremendous quantities of heat (approx. 4.8 x 10/sup 11/ J) must be removed from the magnets (5.9 x 10/sup 9/ gm of iron) and 75,000 liters of cold helium must be supplied to fill the system. In the planning for ISABELLE, this procedure has been estimated to require approximately two weeks. Because of this long cooldown time and the fact that during cooldown the refrigerator will be operated quite differently from its steady-state design configuration, it is important to maximize the cooling capacity and identify the cooldown procedure.

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

1981-01-01

338

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

SciTech Connect

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

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

1999-03-15

339

Vaccine refrigerator testing. Final report  

SciTech Connect

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

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

1990-06-01

340

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

Microsoft Academic Search

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

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

2004-01-01

341

Improved dynamic simulation of multi-temperature industrial refrigeration systems for food chilling, freezing and cold storage  

Microsoft Academic Search

Three refrigeration system simulation environments were used to simulate the performance of two large industrial refrigeration systems used for meat processing. A recently published model for predicting heat release during cooling and freezing enabled the performance of freezers to be predicted more accurately than by earlier models. Weaknesses in room air models and a need for models of room walls

A. C Cleland

1998-01-01

342

Japanese activities in refrigeration technology  

NASA Astrophysics Data System (ADS)

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

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

343

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

344

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

345

49 CFR 173.174 - Refrigerating machines.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

346

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...

347

Effects of cryogenic treatment and refrigerated air on tool wear when machining medium density fiberboard  

Microsoft Academic Search

Cooling of cutting tools with liquid coolants and lubricants is impractical when machining dry wood or wood composites. This study examines the combined effect of cryogenic tool treatment and using refrigerated air for cooling tools on reducing tool wear. A total of four, double-flute, solid, tungsten carbide router bits were used to machine medium density fiberboard with a CNC router.

Judith Gisip; Rado Gazo; Harold A. Stewart

2009-01-01

348

Performance characteristics and optimal analysis of a nanosized quantum dot photoelectric refrigerator  

NASA Astrophysics Data System (ADS)

We study the thermodynamic performance of a nanosized photoelectric refrigerator consisting of three coupled single-level quantum dots embedded between two reservoirs at different temperatures. Based on the quantum master equation, we derive expressions for the cooling power and coefficient of performance (COP) of the refrigerator and plot the characteristic curves between the cooling power and the COP. We analyze the optimal performance parameters under conditions of maximum cooling power and maximum COP, and we discuss the influence of the energy level difference and the temperature ratio on the optimal performance parameters in detail.

Li, Cong; Zhang, Yanchao; Wang, Jianhui; He, Jizhou

2013-12-01

349

Absorption refrigeration and heat pump system with defrost  

SciTech Connect

This patent describes an absorption refrigeration and/or heating system in connection with a primary source of heat, a cooling or heating load, and a heat sink or secondary source, to selectively provide heat to or remove heat from the load, including components. It comprises a multiple effect generator means having multiple desorber components to apply the primary source of heat to an absorption solution pair comprising a highly volatile refrigerant, and an absorbent and to desorb refrigerant from the pair; a condenser means connected to the multiple desorber components of the generator means; an evaporator means connected to the condenser means; an absorber means connected to the evaporator means; a pump means connected between the absorber means and the generator means to transfer solution to the generator means at higher pressure; and a heat transfer subsystem for conveying a working fluid and between the components and having multiple switchable valve means; and pump means.

Petty, S.E.; Cook, F.B.

1990-11-27

350

Review and comparison of magnet designs for magnetic refrigeration  

E-print Network

One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated and the amount of magnet material used. This is done by characterizing each design by a figure of merit magnet design efficiency parameter, $\\Lambda_\\mathrm{cool}$. The designs are then compared and the best design found. Finally recommendations for designing the ideal magnet design are presented based on the analysis of the reviewed designs.

Bjřrk, R; Smith, A; Pryds, N

2014-01-01

351

The effect of coolants on the performance of magnetic micro-refrigerators.  

PubMed

Magnetic refrigeration is an alternative cooling technique with envisaged technological applications on micro- and opto-electronic devices. Here, we present a magnetic micro-refrigerator cooling device with embedded micro-channels and based on the magnetocaloric effect. We studied the influence of the coolant fluid in the refrigeration process by numerically simulating the heat transfer processes using the finite element method. This allowed us to calculate the cooling power of the device. Our results show that gallium is the most efficient coolant fluid and, when used with Gd5Si2Ge2, a maximum power of 11.2 W/mm3 at a working frequency of -5 kHz can be reached. However, for operation frequencies around 50 Hz, water is the most efficient fluid with a cooling power of 0.137 W/mm3. PMID:24738393

Silva, D J; Bordalo, B D; Pereira, A M; Ventura, J; Oliveira, J C R E; Araújo, J P

2014-06-01

352

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

E-print Network

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

Schor, Alisha R. (Alisha Robin)

2007-01-01

353

Combined engine cooling system and waste-heat driven heat pump  

Microsoft Academic Search

An improved engine cooling system is combined with a jet-driven heat pump system for utilizing otherwise wasted heat from an engine to produce refrigeration and heating of cabin, charge air and other media without requiring additional shaft power from the engine. In a closed cycle, vaporized refrigerant fluid is conveyed via jet ejectors from the engine cooling jacket at a

Lowi

1982-01-01

354

Heterostructure integrated thermionic refrigeration  

Microsoft Academic Search

Thermionic emission in heterostructures is investigated for integrated cooling of high power electronic and optoelectronic devices. This evaporative cooling is achieved by selective emission of hot electrons over a barrier layer from the cathode to the anode. As the energy distribution of emitted electrons is almost exclusively on one side of Fermi energy, upon the current flow, strong carrier-carrier and

Ali Shakouri; John E. Bowers

1997-01-01

355

Development of a highly reliable helium refrigeration system--R&D of a highly reliable helium refrigeration system (conventional type)  

NASA Astrophysics Data System (ADS)

The present paper reports the development of the refrigeration system that is applied to 70 MW class superconducting generators. The main subject in developing the refrigeration system for verification tests on site was to develop technology for removing impurities in helium gas, which largely affects its reliability, and to further improve the reliability and efficiency of its main components as screw compressors, turbo expanders, and a low temperature adsorber. Thus this paper deals with its planning and performance testing as well as automatic control in different modes of operation (such as cool-down, steady-state and heat run) and also the reliability analysis. It was verified that the developed refrigeration system demonstrated a higher reliability of 14,637 h mean time between failure, larger than 10,000 h. The total operation time at steady state has reached 9320 h with no failures in the entire testing period.

Ikeuchi, Masamitsu; Yanagi, Hideharu; Machida, Akito

2002-03-01

356

Air cycle combined heating and cooling for the food industry  

Microsoft Academic Search

In the food industry there is often a need to both cook and cool food. Heating and cooling processes are rarely directly linked due to heat from refrigeration processes being insufficient to cook food. Therefore cooling and cooking is usually provided by separate pieces of equipment. This paper presents an air cycle system where the hot air was used for

A. M. Foster; T. Brown; A. J. Gigiel; A. Alford; J. A. Evans

2011-01-01

357

A fundamentally new approach to air-cooled heat exchangers  

Microsoft Academic Search

We describe breakthrough results obtained in a feasibility study of a fundamentally new architecture for air-cooled heat exchangers. A longstanding but largely unrealized opportunity in energy efficiency concerns the performance of air-cooled heat exchangers used in air conditioners, heat pumps, and refrigeration equipment. In the case of residential air conditioners, for example, the typical performance of the air cooled heat

Koplow; Jeffrey P

2010-01-01

358

The refrigerator revolution  

SciTech Connect

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

Ayres, E.; French, H.

1996-09-01

359

Sun synchronous solar refrigeration  

NASA Astrophysics Data System (ADS)

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

360

Development of a refrigeration system for lunar surface and spacecraft applications  

NASA Technical Reports Server (NTRS)

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

Copeland, R. J.

1976-01-01

361

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)

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;

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

362

Heat recovery from refrigeration systems  

Microsoft Academic Search

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

Stamm

1982-01-01

363

A closed-cycle 1 K refrigeration cryostat  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

364

Feasibility study of using a Vuilleumier device for solar cooling  

SciTech Connect

A simplified mathematical model of a Vuilleumier refrigerator is derived, resulting in a system of four nondimensionalized differential equations. The model considers thermal losses due to a finite heat transfer coefficient between the working fluid and the wall, and to regenerator effectiveness less than unity. Numerical solutions are obtained for operating temperatures that would apply to solar powered space cooling applications. The results show that the coefficient of performance of the Vuilleumier refrigerator is slightly below that of a lithium-bromide/water absorption refrigerator for source temperatures below 100C (212F). At higher source temperatures, the performance of the Vuilleumier refrigerator increases significantly.

Rule, T.T.; Wood, B.D.

1980-01-01

365

Design of energy efficient building with radiant slab cooling  

Microsoft Academic Search

Air-conditioning comprises a substantial fraction of commercial building energy use because of compressor-driven refrigeration and fan-driven air circulation. Core regions of large buildings require year-round cooling due to heat gains from people, lights and equipment. Negative environmental impacts include CO2 emissions from electric generation and leakage of ozone-depleting refrigerants. Some argue that radiant cooling simultaneously improves building efficiency and occupant

Zhen Tian

2007-01-01

366

Optimising the refrigeration cycle with a two-stage centrifugal compressor and a flash intercooler  

Microsoft Academic Search

The optimisation of a refrigeration process with a two-stage centrifugal compressor and flash intercooler is presented in this paper. The two-stage centrifugal compressor stages are on the same shaft and the electric motor is cooled with the refrigerant. The performance of the centrifugal compressor is evaluated based on semi-empirical specific-speed curves and the effect of the Reynolds number, surface roughness

Pekka Röyttä; Teemu Turunen-Saaresti; Juha Honkatukia

2009-01-01

367

Experimental investigation of a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine.  

PubMed

In this paper, a thermally-driven thermoacoustic refrigerator system without any moving part is reported. This refrigeration system consists of a thermoacoustic-Stirling heat engine and a thermoacoustic-Stirling refrigerator; that is, the former is the driving source for the latter. Both the subsystems are designed to operate on traveling-wave mode. In the experiment, it was found that the DC-flows had significant negative effect on the heat engine and the refrigerator. To suppress these DC-flows, two flexible membranes were inserted into the two subsystems and worked very well. Then extensive experiments were made to test the influence of different parameters on refrigeration performance of the whole system. The system has so far achieved a no-load temperature of -65 degrees C, a cooling capacity of about 270 W at -20 degrees C and 405 W at 0 degrees C; in fact, the result showed a good prospect of the refrigeration system in room-temperature cooling such as food refrigeration and air-conditioning. PMID:16979679

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

2006-12-22

368

Laser-induced lensing effects in solid-state optical refrigerators  

NASA Astrophysics Data System (ADS)

Laser-induced thermal and population lensing effects in solid-state optical refrigerator materials are quantitatively evaluated. Time-resolved lensing transients in Yb3+ doped ZBLAN and aluminosilicate glasses are measured, and the model decouples thermal and population lensing effects. The analysis yields the net power density, the cooling efficiency, and important photo-physical parameters. The respective values are in good agreement with previously reported parameters for ZBLAN glass. Aluminosilicate glass is found to be a promising optical refrigerator material. We show that the measurement of laser-induced lensing is a valuable tool that can advance the characterization and optimization of materials for cryogenic optical refrigerators.

Silva, J. R.; Andrade, L. H. C.; Lima, S. M.; Hehlen, M. P.; Guyot, Y.; Medina, A. N.; Malacarne, L. C.; Baesso, M. L.; Astrath, N. G. C.

2013-04-01

369

Heat pump system with selective space cooling  

DOEpatents

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

Pendergrass, J.C.

1997-05-13

370

Heat pump system with selective space cooling  

DOEpatents

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

Pendergrass, Joseph C. (Gainesville, GA)

1997-01-01

371

Helium refrigerator-liquefier system for MHD generator  

Microsoft Academic Search

MHD power generators have been investigated in the Electrotechnical Laboratory as one of the National Research and Development Programmes. A helium refrigerator-liquefier system has been developed to cool the superconducting magnet for a 1000 kW class MHD power generator. The turbo-expander with low temperature gas bearings and an alternator had been developed for the MHD project at the Electrotechnical Laboratory

Y. Akiyama; H. Ishii; M. Ando; Y. Mori; M. Yamamoto; R. Wada; K. Mendelssohn

1974-01-01

372

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

DOEpatents

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

Gaul, Christopher J. (Thornton, CO)

2001-01-01

373

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

NASA Astrophysics Data System (ADS)

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

Gurudath Nayak, H.; Venkatarathnam, G.

2009-07-01

374

Comparitive analysis of an automotive air conditioning systems operating with CO2 and R134a  

E-print Network

Institute of Standards and Technology, Gaithersburg, MD, USA Received 10 November 2000; accepted 11 January´ Cette communication e´value les performances des syste`mes de conditionnement d'air automobiles to the Montreal Protocol and consequent regulations, the air-conditioning industry is now in the process

Bahrami, Majid

375

Adiabatic Demagnetisation Refrigerators for Future Sub-Millimetre Space Missions  

NASA Astrophysics Data System (ADS)

Space worthy refrigeration capable of providing a 100 mK and below heat load sink for bolometric detectors will be required for the next generation of sub-millimetre space missions. Adiabatic demagnetisation refrigeration (ADR), being a gravity independent laboratory method for obtaining such temperatures, is a favourable technique for utilisation in space. We show that by considering a 3 salt pill refrigerator rather than the classic single salt pill design the space prohibitive laboratory ADR properties of high magnetic field (6 Tesla) and a<2 K environment (provided by a bath of liquid4He) can be alleviated, while maintaining a sufficient low temperature hold time and short recycle time. The additional salt pills, composed of Gadolinium Gallium Garnet (GGG) provide intermediate cooling stages, enabling operation from a 4 K environment provided by a single 4 K mechanical cooler, thereby providing consumable free operation. Such ADRs could operate with fields as low as 1 Tesla allowing the use of high temperature, mechanically cooled superconducting magnets and so effectively remove the risk of quenching. We discuss the possibility of increasing the hold time from 3 hours, for the model presented, to between 40 and 80 hours, plus reducing the number of salt pills to two, through the use of a more efficient Garnet. We believe the technical advances necessitated by the envisaged ADRs are minimal and conclude that such ADRs offer a long orbital life time, consumable free, high efficiency means of milli-Kelvin cooling, requiring relatively little laboratory development.

Hepburn, I. D.; Davenport, I.; Smith, A.

1995-10-01

376

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

SciTech Connect

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

Ohmori, T.

1986-07-01

377

Insurance Risk for Hydrocarbon Refrigerants in Car Air-Conditioners  

Microsoft Academic Search

Summary Hydrocarbon mixtures have environmental advantages and have success- fully replaced R12 and R134a in over 200,000 US car air-conditioners. On ten popular Australian cars, an extinguished propane torch detected ignition sources and carbon dioxide tracer measured volume and air o w for the pas- senger compartment. The insurance risk increment calculated from these measurements was negative because of the

I. L. Maclaine-cross

378

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

NASA Astrophysics Data System (ADS)

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

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

379

Quantum bath refrigeration towards absolute zero: challenging the unattainability principle.  

PubMed

A minimal model of a quantum refrigerator, i.e., a periodically phase-flipped two-level system permanently coupled to a finite-capacity bath (cold bath) and an infinite heat dump (hot bath), is introduced and used to investigate the cooling of the cold bath towards absolute zero (T=0). Remarkably, the temperature scaling of the cold-bath cooling rate reveals that it does not vanish as T?0 for certain realistic quantized baths, e.g., phonons in strongly disordered media (fractons) or quantized spin waves in ferromagnets (magnons). This result challenges Nernst's third-law formulation known as the unattainability principle. PMID:23002817

Kolá?, M; Gelbwaser-Klimovsky, D; Alicki, R; Kurizki, G

2012-08-31

380

Solid-Vapor Sorption Refrigeration Systems  

E-print Network

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

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

381

Magnetic refrigeration apparatus and method  

DOEpatents

The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

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

1984-01-01

382

Magnetic refrigeration apparatus and method  

SciTech Connect

The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

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

1984-07-17

383

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

384

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

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

2014-01-01

385

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

386

Bipolar pulse field for magnetic refrigeration  

DOEpatents

A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies. 2 figs.

Lubell, M.S.

1994-10-25

387

A generalized magnetic refrigeration scheme  

NASA Astrophysics Data System (ADS)

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

Tamura, Ryo; Ohno, Takahisa; Kitazawa, Hideaki

2014-02-01

388

Computer simulation of solar cooling  

NASA Astrophysics Data System (ADS)

A simplified technique for developing a simulation for analysis of a solar-powered H2O/LiBr absorption cooling system is described. The system considered comprises a flat plate collector, a fluid-filled hot storage tank, an absorber which contains cooling water weak solution, and LiBr closed loops, a heat exchanger to transfer heat between the strong and weak solutions, a generator powered by hot water from the storage tank, a condenser, evaporator, a strong mixture and refrigerant expansion valves. Governing equations are defined for the properties of the binary solution, of the refrigerant, the solar flux, and the air temperature. The numerical performance simulation is detailed for sample winter and summer days, including heat and mass balances.

Elsayed, M. M.; Taha, I. S.; Darwish, M. A.

389

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

NASA Astrophysics Data System (ADS)

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

Gurudath Nayak, H.; Venkatarathnam, G.

2010-11-01

390

Cooling System Using Natural Circulation for Air Conditioning  

NASA Astrophysics Data System (ADS)

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

Okazaki, Takashi; Seshimo, Yu

391

Expendable refrigeration control  

SciTech Connect

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

Clarke, K.J.; Lamb, G.

1986-12-23

392

Characteristics of Single/Double-Effect Combination Absorption Refrigerator  

NASA Astrophysics Data System (ADS)

This report refers to the single/double-effect combination absorption refrigerator, which is driven by waste heat from phosphoric acid fuel cells, and investigates the influence of heat supply conditions, for the purpose of the effectual utilization of the low grade waste heat such as hot water (60~90([°C]). Since waste heat from fuel cells is recovered in two forms of steam and hot water, there is a characteristic of mutual intervention between steam and hot water in absorption refrigeration cycle. For effective use of waste heat, it becomes necessary to clarify this characteristic of mutual intervention. Accordingly, we inquire the effect of heat supply conditions on above mentioned characteristic by simulation. In addition to this, the cooling performance of the absorption refrigerators with two different ways to use hot water (preheating of solution type and generating refrigerant vapor in the low temperature generator type) is investigated. Through out the research, some knowledges for effective use of low grade waste heat are obtained

Kimijima, Shingi; Waragai, Shisei; Uekusa, Tsuneo; Nakao, Masaki; Kawai, Sunao

393

Determining the minimum mass and cost of a magnetic refrigerator  

E-print Network

An expression is determined for the mass of the magnet and magnetocaloric material needed for a magnetic refrigerator and these are determined using numerical modeling for both parallel plate and packed sphere bed regenerators as function of temperature span and cooling power. As magnetocaloric material Gd or a model material with a constant adiabatic temperature change, representing a infinitely linearly graded refrigeration device, is used. For the magnet a maximum figure of merit magnet or a Halbach cylinder is used. For a cost of \\$40 and \\$20 per kg for the magnet and magnetocaloric material, respectively, the cheapest 100 W parallel plate refrigerator with a temperature span of 20 K using Gd and a Halbach magnet has 0.8 kg of magnet, 0.3 kg of Gd and a cost of \\$35. Using the constant material reduces this cost to \\$25. A packed sphere bed refrigerator with the constant material costs \\$7. It is also shown that increasing the operation frequency reduces the cost. Finally, the lowest cost is also found a...

Bjřrk, R; Bahl, C R H; Pryds, N

2014-01-01

394

Superconducting cascade electron refrigerator  

NASA Astrophysics Data System (ADS)

The design and operation of an electronic cooler based on a combination of superconducting tunnel junctions is described. The cascade extraction of hot-quasiparticles, which stems from the energy gaps of two different superconductors, allows for a normal metal to be cooled down to about 100 mK starting from a bath temperature of 0.5 K. We discuss the practical implementation, potential performance, and limitations of such a device.

Camarasa-Gómez, M.; Di Marco, A.; Hekking, F. W. J.; Winkelmann, C. B.; Courtois, H.; Giazotto, F.

2014-05-01

395

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

SciTech Connect

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

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

2012-01-01

396

46 CFR 151.40-11 - Refrigeration systems.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

397

Characteristics of Single/Double-Effect Combination Absorption Refrigerator  

NASA Astrophysics Data System (ADS)

This report refers to the single/double effect combination absorption refrigerator (parallel flow type), which is driven by waste heat from fuel cells, and investigates its characteristics whenthe solution flow rate and the distribution ratio of solution are controlled. Since the waste heat of fuel cells can be recovered in the form of steam and warm water, this absorption refrigerator utilizes them both simultaneously, and can thereby be applied to year-round cooling. In controlling the solution flow rate and distribution ratio of solution, it becomes necessary to clarify the conditions under which the above factors are controlled. The extent to which these conditions can be satisfied becomes the domain in which the operations can be undertaken. Therefore the domain is clarified, and it is shown that an operating point at which the cooling capacity is greatest does exist. In addition to this, it is stated that this operating point varies according to the operating conditions. As a result, an indicator of the high efficiency operation of the absorption refrigerator due to the control of the solution flow rate, and distribution ratio of solution is obtained.

Kimijima, Shingi; Waragai, Shisei; Uekusa, Tsuneo; Nakao, Masaki; Kawai, Sunao

398

Characteristics of Single/Double-Effect Combination Absorption Refrigerator  

NASA Astrophysics Data System (ADS)

In recent years, co-generation system with fuel cell occupies the attention of the world from a standpoint of the environmental protection and the effective utilization of the energy. Since the waste heat of phosphoric acid fuel cell is recovered in two forms of steam (0.6 [MPa]) and hot water (65?90 [°C]), this type of absorption refrigerator is driven by two heat sources. In this paper, we inquire the result of the experiment intented for this absorption refrigerator the standard cooling capacity of which is 35[kW]. It is recognized that there is a mutual intervention when the supply condition of steam pressure is changed. Also the effects of hot water temperature, cooling water temperature and chilled water temperature for the performance of this absorption refrigerator is clarified. As a result, the effectiveness of using steam and hot water simultaneously in year-round operation is shown. Furthermore, it is clarified that the utilization of the low boiling temperature medium as the heat transfer medium for air-conditioner is effective.

Kimijima, Shinji; Waragai, Shisei; Uekusa, Tsuneo; Nakao, Masaki; Kawai, Sunao

399

Improvements of Helium Liquefaction/refrigeration Plants and Applications  

NASA Astrophysics Data System (ADS)

Design features for a new range of helium liquefiers and refrigerators with capacities ranging from 30 to 280 l/h of liquid helium (LHe) and 100 to 900 Watt, respectively. The latest He cold box development shows an increased efficiency due to improved turbine and heat exchanger design. Other benefits of the new design include short cool-down times and a very compact design, which offers better flexibility and process control. The modularity of the system was designed in order to cover a wide range of applications like sophisticated shield cooling at different temperature levels or simultaneous operation modes for He liquefaction and refrigeration purposes. The presentation will highlight the individual improvements in the design. During the presentation the influence of certain parameters like power requirement and cold box inlet pressure in relation to the liquefaction and refrigeration capacity shall be shown and discussed for the range of newly developed Helium liquefiers. In addition, the presentation will cover the latest results of recently installed liquefiers in comparison with the previous model.

Berdais, K.-H.; Wilhelm, H.; Ungricht, Th.

2008-03-01

400

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

SciTech Connect

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.

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

1990-11-01

401

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

402

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

PubMed

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

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

2014-08-01

403

Superinsulation in refrigerators and freezers  

SciTech Connect

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

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

1998-02-01

404

Optimization of materials for thermomagnetic cooling  

SciTech Connect

The authors review thermoelectric transport in a magnetic field. The key physical effect for thermomagnetic cooling is the Ettingshausen effect. They describe the design principles, measurement difficulties and areas where more work can prove fruitful in an exploration of cryogenic refrigeration based on this effect. New principles are discussed to guide the search for new materials and their development.

Migliori, A.; Darling, T.W.; Freibert, F.; Trugman, S.A.; Moshopoulou, E.; Sarrao, J.L.

1997-07-01

405

Application of Newton's law to body cooling  

Microsoft Academic Search

Newton's law of cooling was used to analyze the fall in rectal temperature post mortem in 55 cases during refrigeration in a mortuary. As with solids of low thermal conductivity, there was an initial curvilinearity to the semilog plot lasting 1 to 11 hours (related to pelvic circumference) while the proper internal temperature distribution was becoming established. Thereafter there was

G. W. Molnar; H. J. Hurley; R. Ford

1969-01-01

406

Thermodynamic optimization of conduction-cooled HTS current leads  

NASA Astrophysics Data System (ADS)

A theoretical optimization is performed for the conduction-cooling method of high Tc superconductor (HTS) current leads, which can be applied to the superconducting systems cooled directly by cryogenic refrigerators without liquid helium. The current lead is a series combination of a normal metal conductor at the warmer part and a HTS at the colder part, and is cooled by a contact with distributed or staged refrigerators instead of boil-off helium gas. An analytical method is developed to derive a mathematical expression for the required refrigerator power. By incorporating the critical characteristics of the HTS, it is demonstrated that there exist unique optimal values for the current density of HTS and the joint temperature of the two parts to minimize the total refrigerator power per unit current, for a given length of the HTS. As results of the study, the absolute minimum in the refrigerator power per unit current is presented as a thermodynamic limit and the leads cooled by a two-stage refrigerator are theoretically optimized. Some aspects in practical design are also discussed with a new and useful graphical method.

Chang, Ho-Myung; Van Sciver, Steven W.

407

Heating and Cooling Design for a Container Hut Telephone Exchange  

Microsoft Academic Search

This paper explains the design approach taken for heating and cooling an unmanned container hut, which contains electronic local switching equipment, to maintain the container hut air temperature and relative humidity within a given range. Electronic switch reliability is assured. A new small air-cooled package airconditioner, which has both a refrigerant cycle with a compressor and a thermosiphon in one

K. Ohshima

1983-01-01

408

Thermal links for the implementation of an optical refrigerator  

SciTech Connect

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.

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

409

A class of internally irreversible refrigeration cycles  

NASA Astrophysics Data System (ADS)

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

Ait-Ali, Mohand A.

1996-03-01

410

Refrigerator Thermometers: Cold Facts about Food Safety  

MedlinePLUS

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

411

A review of pulse tube refrigeration  

NASA Technical Reports Server (NTRS)

This paper reviews the development of the three types of pulse tube refrigerators: basic, resonant, and orifice types. The principles of operation are given. It is shown that the pulse tube refrigerator is a variation of the Stirling-cycle refrigerator, where the moving displacer is substituted by a heat transfer mechanism or by an orifice to bring about the proper phase shifts between pressure and mass flow rate. A harmonic analysis with phasors is described which gives reasonable results for the refrigeration power, yet is simple enough to make clear the processes which give rise to the refrigeration. The efficiency and refrigeration power are compared with those of other refrigeration cycles. A brief review is given of the research being done at various laboratories on both one- and two-stage pulse tubes. A preliminary assessment of the role of pulse tube refrigerators is discussed.

Radebaugh, Ray

1990-01-01

412

REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS  

EPA Science Inventory

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

413

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...

414

Krypton based adsorption type cryogenic refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

415

Magnetic refrigeration apparatus with heat pipes  

SciTech Connect

This patent describes an about 4 to about 20 K. refrigeration apparatus comprising: a magnetic field generating means; a fluid contactable magnetic material interacting with the magnetic field produced by the magnetic field generating means so as to be subjected to a cyclically time varying magnetic field; a fluid effective to transfer heat at temperatures between about 4 and about 20K.; an external heat sink; and at least two directional heat pipes, one such pipe disposed between the fluid and the object of cooling whereby heat from the object of cooling is transmitted through the fluid to the magnetic material when the magnetic material absorbs heat. Another such pipe is disposed between the fluid and the external heat sink whereby heat from the magnetic material when the magnetic material is rejecting heat is transmitted through the fluid to the external heat sink, and also whereby the heat from the hot ends of the directional heat pipes is minimally transmitted to the cold ends of the directional heat pipes.

Barclay, J.A.; Coyne, F.

1987-02-17

416

New Regenerative Cycle for Vapor Compression Refrigeration  

SciTech Connect

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

Mark J. Bergander

2005-08-29

417

Design of an adiabatic demagnetization refrigerator for studies in astrophysics  

NASA Technical Reports Server (NTRS)

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

Castles, S.

1983-01-01

418

Comparative study of water, ice and clathrates for cool storage applications  

NASA Astrophysics Data System (ADS)

Cool storage systems are needed in order to reduce the large summer peak loads of many electric utilities in the United States. Cool storage systems will use off-peak electricity during the summer night and will provide air conditioning during the day requiring very little on-peak electricity. This paper describes different cool storage systems and compares the following storage media: water, ice, Refrigerant-11 clathrate, Refrigerant-12 clathrate, Refrigerant-21 clathrate, and mixed clathrates of Refrigerant-11 and Refrigerant-12. Direct- and indirect-charged as well as direct- and indirect-discharged systems are also compared. Hybrid systems (latent and sensible heat) including ice and water, clathrate and liquid, and clathrate and liquid and salts (to reduce the freezing temperature) are also studied. It is concluded that the most appealing system, from the technical and economical point of view, is a system using mixed clathrate, liquid and salt.

Carbajo, J. J.

419

Magnetic refrigeration materials (invited)  

SciTech Connect

Research on the magnetocaloric effect and its application for cooling near room temperature over the past few years has helped to move this phenomenon from a scientific curiosity to an emerging technology. Two of the most important advances include the demonstration which proved that it is possible to obtain significant cooling powers (600 W) at high Carnot efficiencies (60{percent}) and with a large coefficient of performance (15) near room temperature in moderately strong magnetic fields ({le}5 T); and the discovery of the giant magnetocaloric effect in the Gd{sub 5}(Si{sub x}Ge{sub 1{minus}x}){sub 4} series of alloys. Also, new knowledge about the magnetocaloric effect has been gained. This includes: the relationship between the nature of the magnetic transformation(s) and the temperature dependence of the magnetocaloric effect, the entropy utilized in the magnetocaloric process, and the role of impurities on the giant magnetocaloric effect.{copyright} {ital 1999 American Institute of Physics.}

Gschneidner, K.A. Jr.; Pecharsky, V.K. [Ames Laboratory and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011-3020 (United States)] [Ames Laboratory and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011-3020 (United States)

1999-04-01

420

A Multi-Stage Continuous-Duty Adiabatic Demagnetization Refrigerator  

NASA Technical Reports Server (NTRS)

The design for a multi-stage adiabatic demagnetization refrigerator (ADR) that can provide continuous cooling at very low temperatures is presented. The ADR is being developed for use in x-ray, IR and sub-millimeter space astronomy missions which will employ large format detector arrays operating at 50 mK and lower and which may dissipate up to 10 microwatts. It is also being designed to reject heat slowly to a relatively warm heat sink (in the 6-10 K range), so that future missions may use mechanical cryocoolers instead of liquid helium for pre-cooling. The continuous nature of the device gives it a much higher cooling power per unit mass, allowing it to be much smaller and lighter than existing ADRs with comparable performance. Design details are discussed along with prototype test results.

Shirron, P. J.; Blumenstock, K. A.; Canavan, E. R.; DiPirro, M. J.; Tuttle, J. G.; Voellmer, G. M.; Yeager, C. J.

1999-01-01

421

Industrial and commercial refrigeration: DSM offers the hottest ideas for the coolest systems  

SciTech Connect

Refrigeration and air conditioning systems form one of the most important segments of electricity usage. In the UK it is estimated that 17% of all electricity generated is used for refrigeration and air conditioning purposes. Refrigeration systems also represent one of the more complex examples of electricity usage; larger systems usually comprise of several electric motors, compressors, pumps, fans, heat exchangers, etc. This complexity has two effects. Firstly, the average end user finds refrigeration plant relatively difficult to understand. Secondly, it results in an enormous range of design variants that can be applied in any given cooling situation. In the experience of the author there are excellent opportunities to improve the energy efficiency of almost all refrigeration systems. A detailed energy efficiency review of a large industrial refrigeration system will typically yield 20-30% savings with paybacks well under two years. This level of savings can be achieved on existing installations - there is even greater potential when a new system is being designed and built. These energy saving opportunities have been ignored by end users. This is probably because of their lack of understanding of the opportunities as described above. It may also be related to the way in which refrigeration systems tend to be purchased, with great emphasis being placed upon minimum first cost. Hence, refrigeration systems represent an excellent area of opportunity within DSM programmes. A DSM approach is especially appropriate given the relatively high level of technical expertise that is required to identify and implement savings. This is well suited to technically sophisticated organisations such as electricity utilities. This paper discusses a structured approach to the achievement of refrigeration energy efficiency savings within a DSM programme. Such a programme has been very successfully introduced and operated by Ontario Hydro with the support of March Consulting Group.

Gluckman, R.

1994-12-31

422

Solar Refrigerators Store Life-Saving Vaccines  

NASA Technical Reports Server (NTRS)

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

2014-01-01

423

Ternary Dy-Er-Al magnetic refrigerants  

DOEpatents

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

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

1995-07-25

424

21 CFR 1250.34 - Refrigeration equipment.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

425

Method and apparatus for desuperheating refrigerant  

DOEpatents

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

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

1997-01-01

426

Piston sealing arrangement for a cryogenic refrigerator  

SciTech Connect

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

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

1984-02-21

427

Ternary Dy-Er-Al magnetic refrigerants  

DOEpatents

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

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

1995-07-25

428

Compact heat exchanger for refrigeration systems  

Microsoft Academic Search

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

1988-01-01

429

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

Microsoft Academic Search

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

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

2004-01-01

430

An experimental study of waste heat recovery from a residential refrigerator  

Microsoft Academic Search

This paper describes the design, construction, and testing of an integrated heat recovery system which has been designed both to enhance the performance of a residential refrigerator and simultaneously to provide preheated water for an electric hot water heater. A commercial, indirect-heated hot water tank was retrofitted with suitable tubing to permit it to serve as a water cooled condenser

Robert A. Clark; Richard N. Smith; Michael K. Jensen

1996-01-01

431

Multiphysics modeling of a micro-scale Stirling refrigeration system Dongzhi Guo a  

E-print Network

Multiphysics modeling of a micro-scale Stirling refrigeration system Dongzhi Guo a , Alan J.H. Mc Accepted 2 July 2013 Available online Keywords: Stirling microcooler Regenerator Coefficient of performance of arrays of silicon MEMS cooling elements that operate on the Stirling cycle has been designed

McGaughey, Alan

432

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

NASA Technical Reports Server (NTRS)

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

Miller, Franklin K.

2012-01-01

433

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

Microsoft Academic Search

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

R. Z. Wang; R. G. Oliveira

2006-01-01

434

Method and apparatus for cooling high temperature superconductors with neon-nitrogen mixtures  

SciTech Connect

Apparatus and methods for cooling high temperature superconducting materials (HTSC) to superconductive temperatures within the range of 27 K to 77 K using a mixed refrigerant consisting of liquefied neon and nitrogen containing up to about ten mole percent neon by contacting and surrounding the HTSC material with the mixed refrigerant so that free convection or forced flow convection heat transfer can be effected.

Laverman, R.J.; Ban-Yen Lai.

1993-03-16

435

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

Microsoft Academic Search

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

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

2012-01-01

436

Low-temperature magnetic refrigerator  

DOEpatents

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

Barclay, John A. (Los Alamos, NM)

1985-01-01

437

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

438

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

439

Low-temperature magnetic refrigerator  

SciTech Connect

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

Barclay, J. A.

1985-04-02

440

Solar-powered jet refrigerator  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

441

Model Based Control Refrigeration Systems  

E-print Network

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

442

Magnetic refrigeration using flux compression in superconductors  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

443

Waste Heat Powered Ammonia Absorption Refrigeration Unit for LPG Recovery  

SciTech Connect

An emerging DOE-sponsored technology has been deployed. The technology recovers light ends from a catalytic reformer plant using waste heat powered ammonia absorption refrigeration. It is deployed at the 17,000 bpd Bloomfield, New Mexico refinery of Western Refining Company. The technology recovers approximately 50,000 barrels per year of liquefied petroleum gas that was formerly being flared. The elimination of the flare also reduces CO2 emissions by 17,000 tons per year, plus tons per year reductions in NOx, CO, and VOCs. The waste heat is supplied directly to the absorption unit from the Unifiner effluent. The added cooling of that stream relieves a bottleneck formerly present due to restricted availability of cooling water. The 350oF Unifiner effluent is cooled to 260oF. The catalytic reformer vent gas is directly chilled to minus 25oF, and the FCC column overhead reflux is chilled by 25oF glycol. Notwithstanding a substantial cost overrun and schedule slippage, this project can now be considered a success: it is both profitable and highly beneficial to the environment. The capabilities of directly-integrated waste-heat powered ammonia absorption refrigeration and their benefits to the refining industry have been demonstrated.

Donald C, Energy Concepts Co.; Lauber, Eric, Western Refining Co.

2008-06-20

444

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

SciTech Connect

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

None

2010-10-01

445

Split-Stirling Cryogenic Refrigerators For Detector Cooling  

NASA Astrophysics Data System (ADS)

Unfortunately, for user and manufacturer both, the closed-cycle cryogenic cooler to date has deserved its reputation as the "weak-link" in IR systems. When the cooler requires service at intervals of a few hundred hours at best, the quality of the system it serves is unfairly diminished. This paper addresses technological advances in the art of Stirling-cycle coolers which will increasingly cause that image of military cryocoolers to change for the better. A family of split-cycle coolers designed for long MTBF and in the final stages of development is the focus of the discussion. Their technological evolution, from multi-year-MTBF satellite system Stirling coolers developed in the U.S., and the UA 7011 cooler (tne first all-linear, military, production cooler) developed in Holland, is explained. Three new machines are discussed. Both 1/4 watt and 1 watt (nominal capacity) at 80°K linear-resonant, free-dispLacer Stirling coolers designed for thousands of hours of service-free operation are examined. The third machine is an advanced 1/4 watt at 80°K Stirling cooler incorporating the same component improvements in its free-displacer while utilizing a crankshaft-driven compressor. All three are designed to be compatible with standard U.S. 60 element and 120/180 element detector/dewars. The technologies of linear-resonant compressor and free-displacer expanders as embodied in these machines is discussed in sufficient detail that the reasons for their superior performance will he clear.

Lehrfeld, Daniel

1983-08-01

446

Integrated mine cooling and water conditioning system  

SciTech Connect

A method is described comprising: cooling an aqueous liquid at ground level, by means of a refrigeration system which rejects heat, to produce an aqueous ice slurry of ice crystals in the aqueous liquid; separating ice from some of the aqueous ice slurry produced at ground level, washing the ice and melting the ice to produce potable water at ground level, and using the potable water hydrostatic energy to power hydraulic machinery at the location below ground level; feeding the aqueous ice slurry from ground level to a location substantially below ground level to cool that location by heat exchange with the slurry, thereby producing warm aqueous liquid; withdrawing the warm aqueous liquid from the location, returning it to ground level and then cooling the aqueous liquid by means of the refrigeration system to again convert it to an aqueous ice slurry; and recycling the slurry to the location substantially below ground level.

Husain, M.; Nail, J.A.

1988-06-14

447

Two phase cooling for superconducting magnets  

SciTech Connect

A closed circuit tubular cooling system for superconducting magnets offers advantages of limiting boiloff and containing high pressures during quenches. Proper location of automatic valves to lower pressures and protect the refrigerator in the event of quenches is described. Theoretical arguments and exprimental evidence are given against a previously suggested method to determine He two phase flow regimes. If loss of flow occurs due to some types of refrigeration failure and transfer lines have enough heat leak to warm up, quenches are induced when the flow is restored. Examples are taken from experience with the TPC magnet.

Eberhard, P.H.; Gibson, G.A.; Green, M.A.; Ross, R.R.; Smits, R.G.; Taylor, J.D.; Watt, R.D.

1985-08-01

448

A New System for Cooling and Gas Promoting Extraction Utilizing Carbon Dioxide  

Microsoft Academic Search

This paper introduces a new system utilizing carbon dioxide (CO2) to promote gas extraction and to cool a mining face. Based on the phase transformation characteristics of CO2, this system chooses CO2 as the secondary refrigerant to cool mining face; after absorbing heat from the mining face, low temperature CO2 is injected into goaf, cooling goaf and improving desorption of

Wang Lan yun; Jiang Shu guang; Xu Yong liang; Zhang Wei qing; Shao Hao; Wu Zheng yan; Zou Li li

2010-01-01

449

Comparison of Several Eco-Friendly Refrigeration Technologies  

E-print Network

application. Main investigations are contained as follows: 1) The study of adsorption medium pairs Now, major work medium pairs include zeolite-water[6], actived carbon-methanol[7], actived carbon-ammonia[8], silica gel-water[9], chloride of alkaline... sorption cooling machine[J]. International Journal of Refrigeration, 1998, 21(2): 133-141. [11] Meunier F. Performance of adsorption heat pumps: active carbon-methanol and zeolite-water pairs[J]. ASHRAE trans, 1990, 96(1): 267-274. [12] Fuller T A...

Tang, C.; Luo, Q.; Li, X.; Zhu, X.

2006-01-01

450

Optimization of Industrial Refrigeration Systems  

E-print Network

? cooled by the system. Liquid injection cooling im+ poses a load on the compressor (and hence the cont denser) while thermosyphoning imposes a load on the condenser. I The compressor size is based on the evaporator load, the booster performance...? cooled by the system. Liquid injection cooling im+ poses a load on the compressor (and hence the cont denser) while thermosyphoning imposes a load on the condenser. I The compressor size is based on the evaporator load, the booster performance...

Flack, P. J.; Sharp, M. K.; Case, M. E.; Gregory, R. W.; Case, P. L.

451

Free cooling: A total HVAC design concept  

NASA Astrophysics Data System (ADS)

The free cooling concept which relates to system of air conditioning for mild, medium altitude and/or dry, hot climatic areas, whereby chillers and refrigerated cooling may be totally eliminated was examined. Substance of system comprises: (1) precooling of structure overnight; (2) direct exhausting of heat from light fitting; and (3) an improved process of evaporative cooling. Impact is that air conditioning for small and large new buildings may be facilitated at low capital costs with substantially reduces year round energy requirements. Standby chillers may be provided for depending on area and building characteristics.

Janeke, C. E.

452

Two phase cooling for superconducting magnets  

SciTech Connect

Comments on the use of two phase helium in a closed circuit tubular cooling system and some results obtained with the TPC superconducting magnet are given. Theoretical arguments and experimental evidence are given against a previously suggested method to determine helium two phase flow regimes. Two methods to reduce pressure in the magnet cooling tubes during quenches are discussed; (1) lowering the density of helium in the magnet cooling tubes and (2) proper location of pressure relief valves. Some techniques used to protect the refrigerator from too much cold return gas are also mentioned. 10 refs., 1 fig., 5 tabs.

Eberhard, P.H.; Gibson, G.A.; Green, M.A.; Ross, R.R.; Smits, R.G.; Taylor, J.D.; Watt, R.D.

1986-01-01

453

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

SciTech Connect

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

Ross, B.A.

1991-09-01

454

Cryogenic cooling for spacecraft sensors, instruments, and experiments  

NASA Technical Reports Server (NTRS)

Several disciplines requiring in-space cryogenic cooling are identified including high-energy, gamma-ray, and IR astronomy, relativity missions, and superconducting devices. Radiant coolers are limited in terms of temperature ranges and cooling loads. Other spacecraft cryogenic systems include stored solid cryogenic coolers using materials such as hydrogen, neon, argon, and methane. Two such cooler designs are described including one for the Nimbus F limb radiance inversion radiometer and one for the Nimbus G limb infrared monitoring of the atmosphere. Suggestions for increasing the performance of solid cryogenic coolers are made, such as a multimission cooler, a mechanical refrigerator, Stirling-cycle refrigerators, and Vuilleumier mechanized coolers. Techniques for obtaining cryogenic cooling in the milli-K range are identified as dilution refrigeration and adiabatic demagnetization.

Sherman, A.

1978-01-01

455

Practical concerns for refrigerant management in buildings  

SciTech Connect

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

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

1994-01-01

456

Cooling Unit for Electric Power Controller by using Boiling Heat Transfer  

NASA Astrophysics Data System (ADS)

In recent years, semiconductor devices have become faster and more highly integrated, and their capacity has increased. Accompanying this there has also been the increase in the rate of heat generation of devices. We have developed the boiling refrigerant type cooling unit for high power electric controller. The main features of this cooling unit is high cooling performance, low noise, and low electric power. In this study we clarified the influence of cooling air velocity and the number of rows of heat exchanger on the cooling performance of this cooling unit. And it was found that the boiling refrigerant type cooling unit for electric power controller had low noise and low electric power performance compared with conventional air-to-air type cooling unit by testing the two kinds of cooling units.

Kawaguchi, Kiyoshi; Okamoto, Yoshiyuki

457

Solid-state resonant tunneling thermoelectric refrigeration in the cylindrical double-barrier nanostructure  

NASA Astrophysics Data System (ADS)

A solid-state thermoelectric refrigerator with a cylindrical InP/InAs/InP double-barrier heterostructure is proposed. Based on the ballistic electron transport and the asymmetrical transmission, we derive the expressions of the performance parameters of this refrigerator. The cooling rate rather than the coefficient of performance is affected by the area of the inner cylinder. Then through the numerical simulation, a triangular cooling rate region is found with respect to the chemical potential and bias voltage; further, that it is because of the small full width at half maximum of the transmission resonance and the linear relationship between the energy position of resonance and the bias voltage. These tunable results might supply some guide to the cooling in tiny components or devices.

Liu, Nian; Luo, Xiao-Guang; Zhang, Mao-Lian

2014-08-01

458

Integrated Electron-tunneling Refrigerator and TES Bolometer for Millimeter Wave Astronomy  

NASA Technical Reports Server (NTRS)

We describe progress in the development of a close-packed array of bolometers intended for use in photometric applications at millimeter wavelengths from ground- based telescopes. Each bolometer in the may uses 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 ambient bath 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 (approx.10 pW) bolometers to <170 mK while the bolometers are inside a pumped 3He-cooled cryostat operating at approx.280 mK. This significantly lower temperature at the bolometer allows the detectors to approach background-limited performance despite the simple cryogenic system.

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

2005-01-01

459

Refrigerator based on the Coulomb barrier for single-electron tunneling  

NASA Astrophysics Data System (ADS)

We propose a remarkably simple electronic refrigerator based on the Coulomb barrier for single-electron tunneling. A fully normal single-electron transistor is voltage V biased at a gate position such that tunneling through one of the junctions costs an energy of about kBT?eV,EC, where T is the temperature and EC is the transistor charging energy. The tunneling in the junction with positive energy cost cools both leads attached to it. Immediate practical realizations of such a refrigerator make use of Andreev mirrors which suppress heat current while maintaining full electric contact.

Pekola, Jukka P.; Koski, Jonne V.; Averin, Dmitri V.

2014-02-01

460

A compact rotating dilution refrigerator.  

PubMed

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

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

2013-10-01

461

A compact rotating dilution refrigerator  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

462

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

463