Heat transfer property of refrigerant-oil mixture in a flooded evaporator: The role of bubble formation and oil retention

International Nuclear Information System (INIS)

Koo, Kyoung-Min; Kim, Sung-Gyu; Jeong, Young-Man; Lee, Jae-Keun; Kim, Soo Hyung; Lee, Soowon; Park, Nae-Hyun; Na, Byung-Chul; Hwang, Yoon-Jae; Kim, Byung-Soon; Hwang, Joon-Hyun

2013-01-01

We examined the effect of oil retention on the heat transfer performance of a shell-and-tube-type evaporator which had 26 inner tubes and was filled with the refrigerant R-134a. The refrigerant was boiled on the surface of the inner tubes in the evaporator, while chilled water circulated through these tubes. An experimental apparatus was designed to measure both the pressure and temperature profiles at the inlet and outlet of the flooded evaporator. Four windows were installed for observing the operation of the flooded evaporator. A series of experiments were carried out under the following conditions: the refrigerant saturation temperature, 5 .deg. C; refrigerant inlet quality, 0.1; heat fluxes from water to the refrigerant, 5-7 kW/m"2.. The concentration of the oil retained in the refrigerant was then varied up to approximately 10% to observe the effect on the heat transfer performance of the flooded evaporator. Increasing the oil content (i.e., increasing the concentration up to a maximum of approximately 10%) in the refrigerant R134a did not lead to any appreciable reduction in the overall heat transfer coefficient of a flooded evaporator with multiple-inner-tubes. When the oil concentration in the refrigerant was approximately 10%, the heat transfer degradation in the case of the flooded evaporator with multiple-inner-tubes was approximately 11%, which was found to be much smaller than the heat transfer degradation in the case of a flooded evaporator with a single-tube (26-49%). This observation suggested that the oil retained in the refrigerant did not significantly deteriorate the heat transfer performance of the flooded evaporator, presumably because the presence of tube bundles promoted forced convection by agitating bubbles

A numerical study on the oil retention of R410A and PVE oil mixture in multi heat pump system

Energy Technology Data Exchange (ETDEWEB)

Kim, Hak Soo; Kim, Min Soo [Seoul National University, Seoul (Korea, Republic of)

2016-04-15

Predicting an amount of discharged oil from a compressor is necessary to charge the compressor with proper amount of oil. The amount of discharged oil can be predicted by calculating the oil retention amount in each component of a heat pump system. This study suggests a method for calculating the oil retention amount in a heat pump system. In addition, flow pattern of refrigerant and oil mixture in horizontal gas line of refrigerant was ascertained by flow visualization. The oil retention amounts in each component of multi heat pump system were calculated with respect to mass flux of refrigerant, Oil circulation ratio (OCR), length of horizontal and vertical lines. Oil retention amounts in horizontal and vertical gas lines of refrigerant were significant. To validate the model for gas lines of refrigerant, comparison between predicted and experimental oil retention amounts was conducted, and mean absolute percentage error was 15.0%.

Thermodynamic performance of an auto-cascade ejector refrigeration cycle with mixed refrigerant R32 + R236fa

International Nuclear Information System (INIS)

Tan, Yingying; Wang, Lin; Liang, Kunfeng

2015-01-01

In this paper, an auto-cascade ejector refrigeration cycle (ACERC) is proposed to obtain lower refrigeration temperature based on conventional ejector refrigeration and auto-cascade refrigeration principle. The thermodynamic performance of ACERC is investigated theoretically. The zeotropic refrigerant mixture R32 + R236fa is used as its working fluid. A parametric analysis is conducted to evaluate the effects of some thermodynamic parameters on the cycle performance. The study shows that refrigerant mixture composition, condenser outlet temperature and evaporation pressure have effects on performance of ACERC. The theoretical results also indicate that the ACERC can achieve the lowest refrigeration temperature at the temperature level of −30 °C. The application of zeotropic refrigerant mixture auto-cascade refrigeration in the ejector refrigeration cycle can provide a new way to obtain lower refrigeration temperature utilizing low-grade thermal energy. - Highlights: • An auto-cascade ejector refrigerator with R32 + R236fa mixed refrigerant is proposed. • The cycle can obtain a refrigeration temperature at −30 °C temperature range. • The effects of some thermodynamic parameters on the cycle performance are evaluated

Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

2010-10-15

Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes were investigated experimentally. The experimental condensing temperature is 40 C, and nominal oil concentration range is from 0% to 5%. The test results indicate that the presence of oil deteriorates the heat transfer. The deterioration effect is negligible at nominal oil concentration of 1%, and becomes obvious with the increase of nominal oil concentration. At 5% nominal oil concentration, the heat transfer coefficient of R410A-oil mixture is found to have a maximum reduction of 25.1% and 23.8% for 5 mm and 4 mm tubes, respectively. The predictabilities of the existing condensation heat transfer correlations were verified with the experimental data, and Yu and Koyama correlation shows the best predictability. By replacing the pure refrigerant properties with the mixture's properties, Yu and Koyama correlation has a deviation of -15% to + 20% in predicting the local condensation heat transfer coefficient of R410A-oil mixture. (author)

REFRIGERANT/LUBRICANT MIXTURES: PROBLEMS OF APPLICATION AND PROPERTY RESEARCH

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Yu. Semenyuk

2013-10-01

Full Text Available The results and generalizations of thermophysical property research for the refrigerant/lubricant mixtures are summarized. The methodological aspects of the experimental studies of the thermal properties of real working media for vapor compression refrigeration machines and the general principles of the thermodynamic properties simulation for such solutions are analyzed. It is shown that the admixtures of compressor oil in the refrigerant make the efficiency parameters of compressor systems much lower. The question of a selective solubility of the multicomponent refrigerants in compressor oils is discussed.

Liquid viscosity of low-GWP refrigerant mixtures (R32 + R1234yf) and (R125 + R1234yf)

International Nuclear Information System (INIS)

Dang, Yagu; Kamiaka, Takumi; Dang, Chaobin; Hihara, Eiji

2015-01-01

Highlights: • We measured liquid viscosity of low GWP refrigerant R1234yf binary mixtures. • Viscosity of R1234yf mixtures were correlated with the roughness hard-sphere method. • Viscosity of R1234yf mixtures were correlated with the Grunberg and Nissan method. - Abstract: In this work, the viscosity of R1234yf, (R32 + R1234yf), and (R125 + R1234yf) in one-phase liquid was measured. The combined expanded uncertainty of viscosity measurement apparatus of confidence of 0.95 (k = 2) is about 2.0%. The measurements of mixtures containing (30.0, 50.0, and 70.0) wt% R32 or R125 were carried out between T = (283.0 and 323.0) K (at intervals of T = 5 K) and P = (1.58 and 2.74) MPa, with a moving piston viscometer (VISCOpro 1600, accuracy ±1.0%) and a Coriolis flowmeter (Ultramass MKII, accuracy ±0.001 g/ml). The measured data were correlated with a hard-sphere (RSH) method and the Grunberg and Nissan method. The average absolute deviations are (2.2 and 3.3)% for the (R32 + R1234yf) and (R125 + R1234yf) mixtures by RSH method, (2.8 and 1.3)% for the (R32 + R1234yf) and (R125 + R1234yf) mixtures by Grunberg and Nissan method, while (3.5 and 2.4)% for the (R32 + R1234yf) and (R125 + R1234yf) mixtures by RefProp V9.1, respectively

Polyhalogenated hydrocarbon refrigerants and refrigerant oils colored with fluorescent dyes and method for their use as leak detectors

Energy Technology Data Exchange (ETDEWEB)

Parekh, M.

1988-07-19

A leak detectable refrigeration composition is described comprising: (A) a refrigeration liquid selection from the group consisting of: (1) a polyhalogenated hydrocarbon refrigerant; (2) a refrigeration oil selected from the group consisting of naphthenic oils, paraffinic oils, alkylated benzenes, silicones, polyglycols, diesters or triesters of dicarboxylic or tricarboxylic acids, and polyalkyl silicate oils, and (3) a mixture of A(1) and A(2), and (B) a fluorescent dye compound or composition comprising the dye selected from the group consisting of: (1) a fluorescent dye selected from the group consisting of perylene, naphthoxanthene, monocyclic aromatic compounds having an organometallic compound, (2) a solution of fluorescent dye in a solvent, and (3) a mixture of B(1) and B(2). The fluorescent dye compound or composition is soluble in the refrigeration liquid. The concentration of the dye being at least 0.001 grams per 100 grams of the refrigeration liquid.

Performance and energy saving analysis of a refrigerator using hydrocarbon mixture (HC-R134a) as working fluid

Science.gov (United States)

Mohtar, M. N.; Nasution, H.; Aziz, A. A.

2015-12-01

The use of hydrocarbon mixture as a working fluid in a refrigerator system is rarely explored. Almost all domestic refrigerators use hydroflourocarbon R134a (HFC-R134a) as refrigerants. In this study, hydrocarbon gas (HC-R134a) is used as the alternative refrigerant to replace HFC-R134a. It has a composition of R290 (56%), R600a (54.39%) and additive (0.1%wt) blended for the trials. The experiments were conducted with 105 g and 52.5 g refrigerant mass charge, subjected to internal heat load of 0, 1, 2, 3 and 4 kg respectively. The study investigates the coefficient of performance of the refrigerator (COPR) and energy consumption. The results show that the use of HC-R134a as the replaceable refrigerant can save energy ranging from 2.04% to 7.09%, as compared to the conventional HFC-R134a refrigerant. Naturally, the COPR improvement and temperature distribution using HC-R134a are much better than HFC-R134a

Performance computation of window air conditioner with very low GWP near azeotropic refrigerant mixtures as a drop in Substitutes to R22

Directory of Open Access Journals (Sweden)

Vali Shaik Sharmas

2018-01-01

Full Text Available The principal objective of the present study is to compute the thermodynamic performance of window air conditioner based on standard vapour compression refrigeration cycle using R22, R407C and nineteen refrigerant mixtures. In this work nineteen R290/R1270 blends at different compositions are developed. A MATLAB code is developed to compute the thermodynamic performance parameters of all the studied refrigerants at condensing and evaporating temperatures of 54.4°C and 7.2°C respectively. The performance parameters are cooling effect, compressor work, COP, compressor discharge temperature, power per ton of refrigeration and volumetric cooling capacity respectively. Analytical results revealed that COP of new binary mixture R290/R1270 (90/10 by mass % is 2.82% higher among R22, R407C and nineteen studied refrigerants. Energy required by the compressor per ton of refrigeration for R290/R1270 (90/10 by mass % is 2.73% lower among R22, R407C and nineteen studied fluids. The discharge temperature of the compressor for all the nineteen investigated blends are reduced by 6.0-8.9oC compared to R22. Overall thermodynamic performance of window air conditioner with R290/R1270 (90/10 by mass % is better than R22 with significant savings in energy consumption and hence it is an energy efficient ecofriendly refrigerant mixture as a drop in substitute to R22.

Analysis of a variable speed air conditioner considering the R-290/POE ISO 22 mixture effect

International Nuclear Information System (INIS)

Ribeiro, Guilherme B.; Barbosa, Jader R.

2016-01-01

Highlights: • A numerical model that considers the oil-refrigerant mixture effect is proposed. • In order to compare the model, an air conditioner calorimeter was constructed. • The system was evaluated under oil circulation ratios between 1 and 7%. • The presence of oil resulted in a significant SEER deterioration (around 69%). - Abstract: Air-conditioning applications using propane (R-290) have several environmental and thermodynamic advantages over more commonly used refrigerants, such as R-410A and R-22. This paper presents the development of a mathematical model for variable capacity air conditioning systems that use R-290/POE ISO 22 as refrigerant/lubricant. The thermodynamic performance of the refrigeration system is evaluated in terms of the SEER (Seasonal Energy Efficiency Ratio). The thermodynamic properties of the refrigerant/lubricant mixture were obtained from a departure-function approach using the Peng-Robinson equation of state. The effect of the oil on the condenser and evaporator heat transfer coefficients and pressure drops was also taken into account. Sub-models were developed for each component of the air conditioning system, including the connecting lines and the scroll compressor. Furthermore, an air conditioner experimental calorimeter was constructed and tested in order to validate the proposed model.

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

Science.gov (United States)

Ll, Jin; Sato, Haruki; Watanabe, Koichi

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

Thermodynamic analysis on a modified ejector expansion refrigeration cycle with zeotropic mixture (R290/R600a) for freezers

International Nuclear Information System (INIS)

Yan, Gang; Bai, Tao; Yu, Jianlin

2016-01-01

This study presents a modified ejector expansion cycle with zeotropic mixtures (R290/R600a) for freezers, in which an ejector and a phase-separator are employed to enhance the cycle performance. Energetic and exergetic methods are used to theoretically investigate the system operating characteristics. In addition, comparative research among the modified cycle, conventional ejector expansion cycle and basic throttling cycle is carried out. The results demonstrate that the modified cycle exhibits higher refrigeration COP (coefficient of performance), volumetric refrigeration capacity and system exergy efficiency than conventional ejector expansion cycle and basic throttling cycle. Under the given operation conditions, the system performance improvements of the modified cycle in terms of the COP, refrigeration capacity and system exergy efficiency over the basic throttling cycle could reach about 56.0%, 4.5% and 77.7%, respectively. The performance characteristics of the proposed cycle show its potential practical advantages in freezer applications. - Highlights: • A zeotropic mixture based ejector refrigeration cycle with a separator is proposed. • Comparative research among the different cycles is carried out. • Energetic and exergetic methods are used to investigate the system performance. • The COP and system exergy efficiency are improved by 56.0% and 77.7%, respectively.

Performance of refrigerating machineries with new refrigerants; Performance des machines frigorifiques avec les nouveaux refrigerants

Energy Technology Data Exchange (ETDEWEB)

Bailly, A; Jurkowski, R [CIAT, 01 - Culoz (France)

1998-12-31

This paper reports on a comparative study of the thermal performances of different refrigerants like R-22, R-134a, R-404A and R-407C when used as possible substitutes for the HCFC22 refrigerant in a given refrigerating machinery equipped with compact high performance plate exchangers. Thermal performances are compared in identical operating conditions. The behaviour of the two-phase exchange coefficient is analyzed with respect to the different parameters. The composition of the mixture after one year of operation has been analyzed too and the influence of oil on the performances is studied. (J.S.)

Performance of refrigerating machineries with new refrigerants; Performance des machines frigorifiques avec les nouveaux refrigerants

Energy Technology Data Exchange (ETDEWEB)

Bailly, A.; Jurkowski, R. [CIAT, 01 - Culoz (France)

1997-12-31

This paper reports on a comparative study of the thermal performances of different refrigerants like R-22, R-134a, R-404A and R-407C when used as possible substitutes for the HCFC22 refrigerant in a given refrigerating machinery equipped with compact high performance plate exchangers. Thermal performances are compared in identical operating conditions. The behaviour of the two-phase exchange coefficient is analyzed with respect to the different parameters. The composition of the mixture after one year of operation has been analyzed too and the influence of oil on the performances is studied. (J.S.)

Experimental study of hydrocarbon mixtures to replace HFC-134a in a domestic refrigerator

International Nuclear Information System (INIS)

Wongwises, Somchai; Chimres, Nares

2005-01-01

This work presents an experimental study on the application of hydrocarbon mixtures to replace HFC-134a in a domestic refrigerator. The hydrocarbons investigated are propane (R290), butane (R600) and isobutane (R600a). A refrigerator designed to work with HFC-134a with a gross capacity of 239 l is used in the experiment. The consumed energy, compressor power and refrigerant temperature and pressure at the inlet and outlet of the compressor are recorded and analysed as well as the distributions of temperature at various positions in the refrigerator. The refrigerant mixtures used are divided into three groups: the mixture of three hydrocarbons, the mixture of two hydrocarbons and the mixture of two hydrocarbons and HFC-134a. The experiments are conducted with the refrigerants under the same no load condition at a surrounding temperature of 25 deg. C. The results show that propane/butane 60%/40% is the most appropriate alternative refrigerant to HFC-134a

Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode

Science.gov (United States)

Sreenivas, Bura; Nayak, H. Gurudath; Venkatarathnam, G.

2017-01-01

The composition of the refrigerant mixture in circulation during steady state operation of J-T and allied refrigerators is not the same as that charged due to liquid hold up in the heat exchangers and phase separators, as well as the differential solubility of different refrigerant components in the compressor lubricating oil. The performance of refrigerators/liquefiers operating on mixed refrigerant cycles is dependent on the mixture composition. It is therefore important to charge the right mixture that results in an optimum composition in circulation during steady state operation. The relationship between the charged and circulating composition has been experimentally studied in a J-T refrigerator operating in the liquid refrigerant supply (LRS) mode and an auto refrigerant cascade refrigerator (with a phase separator) operating in the gas refrigerant supply (GRS) mode. The results of the study are presented in this work. The results show that the method presented earlier for J-T refrigerators operating in GRS mode is also applicable in the case of refrigerators studied in this work.

Evaporation of new refrigerants on tubes with improved surfaces; Evaporation de nouveaux refrigerants sur des tubes a surface amelioree

Energy Technology Data Exchange (ETDEWEB)

Kattan, N.; Favrat, D.; Thome, J. R.; Nidegger, E.; Zuercher, O. [Ecole Polytechnique Federale, Lab. d` Energetique Industrielle (LENI), Lausanne (Switzerland)

1995-07-15

The substitution of old refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, request a good knowledge of heat transfer properties of substitute fluids. The test measurements in LENI test facility (concentric tubes with water flowing in a counter-current flow) with new refrigerants like HFC134a, HCFC123, R-404A, R-402A, have established a new data bank with new refrigerants, a comparison with old refrigerants like CFC11, CFC12 CFC/HCFC502 and with existent correlations. Correlations were programmed to calculate and compare heat transfer coefficient during the tests. To develop a new correlation based on flow regimes, a high speed Sony video tape camera is used to observe and identify flow patterns. Important images are captured, digitalized, stored for later analysis and sent to a color plotter. Several flow pattern maps were programmed and compared to flow regimes observed on the test rig. Local flow boiling heat transfer coefficients were measured for HFC134a and HCFC123 evaporating inside a microfin tube. In addition, microfin heat transfer augmentation relative to plain tube test data was investigated. The presence of oil in the evaporator has an effect on heat transfer coefficient. Local flow boiling heat transfer coefficients were measured for refrigerant HFC134a-oil ester (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of refrigerants and lubricating oils is developed. A very high accuracy, straight vibrating tube type of density flowmeter is used to measure oil concentrations of flowing HFC134a-oil mixtures. (author) 28 figs., 25 refs.

Evaporation heat transfer for R-22 and R-407C refrigerant-oil mixture in a microfin tube with a U-bend

Energy Technology Data Exchange (ETDEWEB)

Cho, Keumnam; Tae, Sang-Jin [Sungkyunkwan University, Suwon (D.P.R. of Korea). School of Mechanical Engineering

2000-05-01

Evaporation heat transfer experiments for two refrigerants, R-407C and R-22, mixed with polyol ester and mineral oils were performed in straight and U-bend sections of a microfin tube. Experimental parameters include an oil concentration varied from 0 to 5%, an inlet quality varied from 0.1 to 0.5, two mass fluxes of 219 and 400 kg m{sup -2} s{sup -1} and two heat fluxes of 10 and 20 kW m{sup -2}. Pressure drop in the test section increased by approximately 20% as the oil concentration increased from 0 to 5%. Enhancement factors decreased as oil concentration increased under inlet quality of 0.5, mass flux of 219 kg m{sup -2} s{sup -1} and heat flux of 10 kW m{sup -2}, whereas they increased under inlet quality of 0.1, mass flux of 400 kg m{sup -2} s{sup -1}, and heat flux of 20 kW m{sup -2}. The local heat transfer coefficient at the outside curvature of a U-bend was larger than that at the inside curvature of a U-bend, and the maximum value occurred at the 90{sup o} position of the U-bend. The heat transfer coefficient was larger in a region of 30 tube diameter length at the second straight section than that at the first straight section. (author)

Use of nanoparticles to make mineral oil lubricants feasible for use in a residential air conditioner employing hydro-fluorocarbons refrigerants

Energy Technology Data Exchange (ETDEWEB)

Wang, Ruixiang [School of Energy and Power Engineering, Xi' an Jiaotong University 710049 Xi' an (China); School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, No. 1, Zhanlan Guan Road, Beijing 100044 (China); Wu, Qingping; Wu, Yezheng [School of Energy and Power Engineering, Xi' an Jiaotong University 710049 Xi' an (China)

2010-11-15

The application of nano-fluids in refrigerating systems is considered to be a potential way to improve the energy efficiency and reliability of HVAC and R facilities and to make economic the use of environment-friendly refrigerants. In this paper, we report a method that uses nanoparticles to enhance the energy efficiency of retrofitted residential air conditioners (RAC) employing HFCs as alternative refrigerants. The reliability and performance of RAC with nanoparticles in the working fluid have been investigated experimentally. A new mineral-based nano-refrigeration oil (MNRO), formed by blending some nanoparticles (NiFe{sub 2}O{sub 4}) into naphthene based oil B32, was employed in the RAC using R410a as refrigerant. A method showing how to disperse the NiFe{sub 2}O{sub 4} nanoparticles in the mineral oil refrigeration lubricants is presented together with an investigation of their stability. The solubilities of the new MNRO in R134a, R407C, R410a and R425a were measured. The performances of the RAC, such as the cooling/heating capacity, the power input and the energy efficiency ratio, were determined. The results indicate that the mixture of R410a/MNRO works normally in the RAC. The cooling/heating EER of the RAC increased about 6% by replacing the Polyol-Easter oil VG 32 lubricant with MNRO. (author)

Abatement of CFC emissions in air conditioning and refrigerating technology. Partial project 9. Minderung von FCKW-Emissionen in der Klima- und Kaeltetechnik. Teilvorhaben 9; Bestimmung thermodynamischer Eigenschaften des Gemisches R 152a - R 134a. Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

There are two ozone-neutral materials that could substitute the strongly ozone-destructive refrigerant R12, namely 1,1 difluoroethane (R152a) and 1,1,1,2 tetrafluoroethane (R134a). R152a has excellent thermodynamic and energetic properties. It is innocuous and easy to produce. Its great drawback is its inflammability due to the four hydrogen atoms per molecule. R134a is chemically inert and non-flammable, but its mixing behaviour with refrigerating oils poses problems. Idealised refrigeration processes using R134a show somewhat lower performance data than these using R128 so R134a would be expected to have a slightly greater primary energy demand. It may turn out that by using a mixture of R152a and R134a the unfavourable properties of the two components when used singly can be mutually moderated or completely neutralised, as follows. Addition of R134a neutralises the inflammability of R152a. A mixture may be expected to have more favourable thermodynamic and energetic properties than R134a alone. The foremost aim of the project was to determine by experiment the thermodynamic properties of the mixture of R152a and R134a. (orig./EF)

Experimental investigation and correlation of two-phase frictional pressure drop of R410A-oil mixture flow boiling in a 5 mm microfin tube

Energy Technology Data Exchange (ETDEWEB)

Ding, Guoliang; Hu, Haitao; Huang, Xiangchao [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China); Gao, Yifeng [International Copper Association, Shanghai Office, Shanghai 200020 (China)

2009-01-15

This study presents experimental two-phase frictional data for R410A-oil mixture flow boiling in an internal spiral grooved microfin tube with outside diameter of 5 mm. Experimental parameters include the evaporation temperature of 5 C, the mass flux from 200 to 400 kg m{sup -2} s{sup -1}, the heat flux from 7.46 to 14.92 kW m{sup -2}, the inlet vapor quality from 0.1 to 0.8, and nominal oil concentration from 0 to 5%. The test results show that the frictional pressure drop of R410A initially increases with vapor quality and then decreases, presenting a local maximum in the vapor quality range between 0.7 and 0.8; the frictional pressure drop of R410A-oil mixture increases with the mass flux, the presence of oil enhances two-phase frictional pressure drop, and the effect of oil on frictional pressure drop is more evident at higher vapor qualities where the local oil concentrations are higher. The enhanced factor is always larger than unity and increases with nominal oil concentration at a given vapor quality. The range of the enhanced factor is about 1.0-2.2 at present test conditions. A new correlation to predict the local frictional pressure drop of R410A-oil mixture flow boiling inside the internal spiral grooved microfin tube is developed based on local properties of refrigerant-oil mixture, and the measured local frictional pressure drop is well correlated with the empirical equation proposed by the authors. (author)

Analytical computation of thermodynamic performance parameters of actual vapour compression refrigeration system with R22, R32, R134a, R152a, R290 and R1270

Directory of Open Access Journals (Sweden)

Vali Shaik Sharmas

2018-01-01

Full Text Available The present work focuses on analytical computation of thermodynamic performance of actual vapour compression refrigeration system by using six pure refrigerants. The refrigerants are namely R22, R32, R134a, R152a, R290 and R1270 respectively. A MATLAB code is developed to compute the thermodynamic performance parameters of actual vapour compression system such as refrigeration effect, compressor work, COP, power per ton of refrigeration, compressor discharge temperature and volumetric refrigeration capacity at condensing and evaporating temperatures of 54.4oC and 7.2oC respectively. Analytical results exhibited that COP of both R32 and R134a are 15.95% and 11.71% higher among the six investigated refrigerants. However R32 and R134a cannot be replaced directly into R22 system. This is due to their higher compressor discharge temperature and poor volumetric capacity respectively. The discharge temperature of both R1270 and R290 are lower than R22 by 20-26oC. Volumetric refrigeration capacity of R1270 (3197 kJ/m3 is very close to that of volumetric capacity of R22 (3251 kJ/m3. Both R1270 and R290 shows good miscibility with R22 mineral oil. Overall R1270 would be a suitable ecofriendly refrigerant to replace R22 from the stand point of ODP, GWP, volumetric capacity, discharge temperature and miscibility with mineral oil although its COP is lower.

Flow boiling of refrigerant-oil mixtures; Transferts de chaleur dans un melange constitue de fluide frigorigene et d'huile

Energy Technology Data Exchange (ETDEWEB)

Feidt, M

1999-10-13

The phase out of chlorine containing refrigerants (CFC and HCFC) has led to the introduction of new refrigerants and lubricants to the market. The interest in using HFC fluids as working fluids to replace fluids harmful to the stratospheric ozone layer. The study presents the influence of synthetic oil (POE ISO 68) on flow boiling of refrigerants R134a (pure fluid) and R410A (R32/R125 50%/50%). Local and average heat transfer coefficients and pressure drops have been measured for a smooth horizontal tube. The distribution of the heat transfer coefficient at the inner wall has been obtained from solving the inverse heat conduction problem (IHCP) and resulted in a local combination of nucleate and convective contributions to flow boiling. Local heat transfer coefficients have been averaged and displayed as a function of the vapour quality. For R134a: small amounts of oil (1% to 6%) in the liquid phase increased the heat transfer coefficient at low and intermediate vapour qualities (less than 0.60) compared to pure fluid. However a hugh reduction of the heat transfer has been observed at higher vapour qualities. For R410A : oil dramatically decreases the heat transfer coefficient compared to pure fluid. Pressure drops are also affected by small amounts of lubricant: an important increase has been noted for both fluids. Available design methods for flow boiling heat transfer coefficient (superposition, enhancement, asymptotic) badly predict the experimental results. Nevertheless a new design method accounting for flow patterns has shown good agreements. The influence of the lubricant on the heat transfer is discussed and a new proposition is made to calculate pressure drops. (author)

COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

Science.gov (United States)

Westra, Douglas G.

1993-01-01

With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

Flow boiling of refrigerant-oil mixtures; Transferts de chaleur dans un melange constitue de fluide frigorigene et d'huile

Energy Technology Data Exchange (ETDEWEB)

Feidt, M.

1999-10-13

The phase out of chlorine containing refrigerants (CFC and HCFC) has led to the introduction of new refrigerants and lubricants to the market. The interest in using HFC fluids as working fluids to replace fluids harmful to the stratospheric ozone layer. The study presents the influence of synthetic oil (POE ISO 68) on flow boiling of refrigerants R134a (pure fluid) and R410A (R32/R125 50%/50%). Local and average heat transfer coefficients and pressure drops have been measured for a smooth horizontal tube. The distribution of the heat transfer coefficient at the inner wall has been obtained from solving the inverse heat conduction problem (IHCP) and resulted in a local combination of nucleate and convective contributions to flow boiling. Local heat transfer coefficients have been averaged and displayed as a function of the vapour quality. For R134a: small amounts of oil (1% to 6%) in the liquid phase increased the heat transfer coefficient at low and intermediate vapour qualities (less than 0.60) compared to pure fluid. However a hugh reduction of the heat transfer has been observed at higher vapour qualities. For R410A : oil dramatically decreases the heat transfer coefficient compared to pure fluid. Pressure drops are also affected by small amounts of lubricant: an important increase has been noted for both fluids. Available design methods for flow boiling heat transfer coefficient (superposition, enhancement, asymptotic) badly predict the experimental results. Nevertheless a new design method accounting for flow patterns has shown good agreements. The influence of the lubricant on the heat transfer is discussed and a new proposition is made to calculate pressure drops. (author)

Numerical analysis of an air condenser working with the refrigerant fluid R407C

International Nuclear Information System (INIS)

Aprea, Ciro; Maiorino, Angelo

2007-01-01

As CFC (clorofluorocarbon) and HCFC (hydrochlorofluorocarbon) refrigerants which have been used as refrigerants in a vapour compression refrigeration system were know to provide a principal cause to ozone depletion and global warming, production and use of these refrigerants have been restricted. Therefore, new alternative refrigerants should be searched for, which fit to the requirements in an air conditioner or a heat pump, and refrigerant mixtures which are composed of HFC (hydrofluorocarbon) refrigerants having zero ODP (ozone depletion potential) are now being suggested as drop-in or mid-term replacement. However also these refrigerants, as the CFC and HCFC refrigerants, present a greenhouse effect. The zeotropic mixture designated as R407C (R32/R125/R134a 23/25/52% in mass) represents a substitute of the HCFC22 for high evaporation temperature applications as the air-conditioning. Aim of the paper is a numerical-experimental analysis for an air condenser working with the non azeotropic mixture R407C in steady-state conditions. A homogeneous model for the condensing refrigerant is considered to forecast the performances of the condenser; this model is capable of predicting the distributions of the refrigerant temperature, the velocity, the void fraction, the tube wall temperature and the air temperature along the test condenser. Obviously in the refrigerant de-superheating phase the numerical analysis becomes very simple. A comparison with the measurements on an air condenser mounted in an air channel linked to a vapour compression plant is discussed. The results show that the simplified model provides a reasonable estimation of the steady-state response and that this model is useful to design purposes

OPTIMAL SYSNTHESIS PROCESSES OF LOW-TEMPERATURE CONDENSATION ASSOCIATED OIL GAS PLANT REFRIGERATION SYSTEM

Directory of Open Access Journals (Sweden)

O. Ostapenko

2015-10-01

Full Text Available Design of modern high-efficient systems is a key priority for the Energy Sector of Ukraine. The cooling technological streams of gas and oil refineries, including air coolers, water cooling and refrigeration systems for specific refrigerants are the objectives of the present study. Improvement of the refrigeration unit with refrigerant separation into fractions is mandatory in order to increase cooling capacity, lowering the boiling point of coolant and increasing the coefficient of target hydrocarbons extraction from the associated gas flow. In this paper it is shown that cooling temperature plays significant role in low-temperature condensation process. Two operation modes for refrigeration unit were proposed: permanent, in which the concentration of the refrigerant mixture does not change and dynamic, in which the concentration of refrigerant mixtures depends on the ambient temperature. Based on the analysis of exergy losses the optimal concentration of refrigerant mixtures propane/ethane for both modes of operation of the refrigeration unit has been determined. On the basis of the conducted pinch-analysis the modification of refrigeration unit with refrigerant separation into fractions was developed. Additional recuperative heat exchangers for utilization heat were added to the scheme. Several important measures to increase the mass flow rate of refrigerant through the second section of the refrigeration centrifugal compressor from 22.5 to 25 kg/s without violating the agreed operational mode of the compressor sections were implemented.

Review of numerical simulation of capillary tube using refrigerant mixtures

Energy Technology Data Exchange (ETDEWEB)

Garcia-Valladares, O. [Centro de Investigacion en Energia de la UNAM, Morelos (Mexico)

2004-05-01

A detailed one-dimensional steady and transient state numerical simulation of the thermal and fluid-dynamic behaviour of capillary tube expansion devices considering metastable region and working with pure and mixed refrigerants has been developed and presented in previous works [Appl. Therm. Eng. 22 (2002) 173; Appl. Therm. Eng. 22 (2002) 379]. The discretized governing equations are coupled using an implicit step-by-step method. Due to the changes observed in the thermo-physical properties of mixtures using REFPROP v7.0 [Reference Fluid Thermodynamic and Transport Properties, NIST Standard Reference Database 23, Gaithersburg, MD 20899, USA, 2002] compared to REFPROP v5.0 [NIST Thermodynamic Properties of Refrigerants and Refrigerant Mixtures Database, Standard Reference Data Program, Gaithersburg, MD 20899, USA (February 1996)]; an extensive comparison of the numerical simulation developed with experimental data presented in the technical literature will be shown in order to demonstrate the accuracy of this detailed model. Finally, refrigerant-specific rating charts to predict in an easy way R-407C flow rates through adiabatic capillary tube are shown and used. (author)

Review of numerical simulation of capillary tube using refrigerant mixtures

International Nuclear Information System (INIS)

Garcia-Valladares, O.

2004-01-01

A detailed one-dimensional steady and transient state numerical simulation of the thermal and fluid-dynamic behaviour of capillary tube expansion devices considering metastable region and working with pure and mixed refrigerants has been developed and presented in previous works [Appl. Therm. Eng. 22 (2002) 173; Appl. Therm. Eng. 22 (2002) 379]. The discretized governing equations are coupled using an implicit step-by-step method. Due to the changes observed in the thermo-physical properties of mixtures using REFPROP v7.0 [Reference Fluid Thermodynamic and Transport Properties, NIST Standard Reference Database 23, Gaithersbug, MD 20899, USA, 2002] compared to REFPROP v5.0 [NIST Thermodynamic Properties of Refrigerants and Refrigerant Mixtures Database, Standard Reference Data Program, Gaithersbug, MD 20899, USA (February 1996)]; an extensive comparison of the numerical simulation developed with experimental data presented in the technical literature will be shown in order to demonstrate the accuracy of this detailed model. Finally, refrigerant-specific rating charts to predict in an easy way R-407C flow rates through adiabatic capillary tube are shown and used

Literature survey of heat transfer enhancement techniques in refrigeration applications

Energy Technology Data Exchange (ETDEWEB)

Jensen, M.K.; Shome, B. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

1994-05-01

A survey has been performed of the technical and patent literature on enhanced heat transfer of refrigerants in pool boiling, forced convection evaporation, and condensation. Extensive bibliographies of the technical literature and patents are given. Many passive and active techniques were examined for pure refrigerants, refrigerant-oil mixtures, and refrigerant mixtures. The citations were categorized according to enhancement technique, heat transfer mode, and tube or shell side focus. The effects of the enhancement techniques relative to smooth and/or pure refrigerants were illustrated through the discussion of selected papers. Patented enhancement techniques also are discussed. Enhanced heat transfer has demonstrated significant improvements in performance in many refrigerant applications. However, refrigerant mixtures and refrigerant-oil mixtures have not been studied extensively; no research has been performed with enhanced refrigerant mixtures with oil. Most studies have been of the parametric type; there has been inadequate examination of the fundamental processes governing enhanced refrigerant heat transfer, but some modeling is being done and correlations developed. It is clear that an enhancement technique must be optimized for the refrigerant and operating condition. Fundamental processes governing the heat transfer must be examined if models for enhancement techniques are to be developed; these models could provide the method to optimize a surface. Refrigerant mixtures, with and without oil present, must be studied with enhancement devices; there is too little known to be able to estimate the effects of mixtures (particularly NARMs) with enhanced heat transfer. Other conclusions and recommendations are offered.

Evaporation of new refrigerants on tube with improved surfaces. Final report. Appendices: A, B, C, D, E and F; Evaporation de nouveaux refrigerants sur des tubes a surface amelioree. Rapport final. Annexes: A, B, C, D, E et F

Energy Technology Data Exchange (ETDEWEB)

Kattan, N.; Favrat, D.; Thome, J. R.; Nidegger, E.; Zuercher, O. [Ecole Polytechnique Federale, Lab. d` Energetique Industrielle (LENI), Lausanne (Switzerland)

1995-07-15

The substitution of old refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, request a good knowledge of heat transfer properties of substitute fluids. The test measurements in LENI test facility (concentric tubes with water flowing in a counter-current flow) with new refrigerants like HFC134a, HCFC123, R-402A, have established a new data bank with new refrigerants, a comparison with old refrigerants like CFC11, CFC12 CFC/HCFC502 and with existent correlations. Correlations were programmed to calculate and compare heat transfer coefficient during the tests. To develop a new correlation based on flow regimes, a high speed Sony video tape camera is used to observe and identify flow patterns. Important images are captured, digitalized, stored for later analysis and sent to a color plotter. Several flow pattern maps were programmed and compared to flow regimes observed on the test rig. Local flow boiling heat transfer coefficients were measured for HFC134a and HCFC123 evaporating inside a microfin tube. In addition, microheat transfer augmentation relative to plain tube test data was investigated. The presence of oil in the evaporator has an effect on heat transfer coefficient. Local flow boiling heat transfer coefficients were measured for refrigerant HFC134a-oil ester (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of refrigerants and lubricating oils is developed. A very high accuracy, straight vibrating tube type of density flowmeter is used to measure oil concentrations of flowing HFC134a-oil mixtures. (author) figs., tabs., refs.

Substitution of the CFCs R-11, R-13, R-503, R-13B1, R-113, R-114 and R-12B1 in existing refrigerating, air-conditioning and heat pump systems with refrigerants of low ozone depletion potential in the Federal Republic of Germany. Status report; Ersatz der FCKW R11, R13, R503, R13B1, R113, R114, und R12B1 in bestehenden Kaelte-, Klima- und Waermepumpenanlagen in der Bundesrepublik Deutschland durch Kaeltemittel mit geringem Ozonabbaupotential. Statusbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-11-01

The technical basics and the state of the art for the substitution of the CFC refrigerants R-11, R-13, R-503, R-13B1, R-113, R-114 and R-12B1 in existing refrigeration systems are described and explained. The report contains an overview of the current applications of these refrigerants in the FRG, a review and discussion of existing substitutes, the presentation and evaluation of research and experiences with the conversion to alternative refrigerants, the presentation of the required infrastructure and a discussion of the technical feasibility. The conversion of existing systems to refrigerants of lower ozone depletion potential is in conclusion evaluated with regard to its technical feasibility, environmental relevance and economic efficiency. (orig.) [Deutsch] Es werden die technischen Grundlagen und der Stand der Technik zum Ersatz der FCKW-Kaeltemittel R11, R13, R503, R13B1, R113, R114 und R12B1 in bestehenden Kaelteanlagen dargestellt und erlaeutert. Der Bericht beinhaltet einen Ueberblick ueber die derzeitige Anwendung dieser Kaeltemittel in der BRD, die Vorstellung und Diskussion existierender Ersatzstoffe, die Darstellung und Bewertung der Forschung und Erfahrungen zu Umruestungen auf Ersatzstoffe, die Vorstellung der erforderlichen Infrastruktur und die Diskussion der technischen Durchfuehrbarkeit. Die Umstellung bestehender Anlagen auf Kaeltemittel mit geringerem Ozonabbaupotential wird abschliessend hinsichtlich der technischen Durchfuehrbarkeit, der Umweltrelevanz und der Wirtschaftlichkeit bewertet. (orig.)

The use of an MHV-2 equation of state for modeling the thermodynamic properties of refrigerant mixtures

International Nuclear Information System (INIS)

Morrison, J.D.; Barley, M.H.; Parker, I.B.

1995-01-01

This paper reports on the development and application of a thermodynamic model based on the second-order Modified Huron Vidal equation of state (MHV-2) to predict the properties of ternary mixtures of the refrigerants R32, R125, and R134a. The mixing rules of this equation of state have been used to incorporate directly an activity-coefficient model for the excess Gibbs free energy. The parameters for the activity-coefficient model have been derived from experimental VLE data for binary mixtures. This methodology has enabled the production of a thermodynamically consistent model which can be used to predict the phase equilibria of R32/R125/R134a mixtures. The input data used in the model are presented in the paper and the predictions of the model are compared with available experimental data. The model has been used to predict the behavior of ternary refrigerant blends of R32/R125/R134a in fractionation scenarios, such as liquid charging and vapor leakage, which are of direct interest to the refrigeration industry. Details of these applications and comparisons with experimental data are discussed, along with other general uses of the thermodynamic model

Test Report #33: Compressor Calorimeter Test of R-410A Alternative: R-32/R-134a Mixture Using a Scroll Compressor

Energy Technology Data Exchange (ETDEWEB)

Shrestha, Som [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Vishaldeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2014-02-18

This report investigates the tested performance of lower - GWP candidate refrigerant, 94.07 wt% R - 32 + 5.93 wt % R - 134 a mixture (hereafter referred to as R - 32/134a), as an alternative to baseline refrigerant R - 410 A using a 36,000 Btu/hr compressor calorimeter located at the Heat Exchanger Advanced Testing Facility at Oak Ridge National Laboratory . These tests were conducted during May and August 2013. R - 410A is a near - azeotropic blend of R - 32 and R - 125 with 0.5/0.5 mass fraction and has a GWP 100 of 2100. R - 32 and R - 134a are pure refrigerants and have GWP 100 of 716 and 1370 1, respectively. Based on the GWP 100 values of pure refrigerants and their mass fraction in the blend, GWP 100 of R - 32/134a, which is under development by National Refrigerant, is 755. This report compares various performance parameters, such as cooling capacity, compressor power, refrigerant mass flow rate, EER, isentropic efficiency and discharge temperature of the alternative refrigerant to that of R - 410 A.

Performance of a Throttle Cycle Refrigerator with Nitrogen-Hydrocarbon and Argon-Hydrocarbon Mixtures

Science.gov (United States)

Venkatarathnam, G.; Senthil Kumar, P.; Srinivasa Murthy, S.

2004-06-01

Throttle cycle refrigerators are a class of vapor compression refrigerators that can provide refrigeration at cryogenic temperatures and operate with refrigerant mixtures. The performance of our prototype refrigerators with nitrogen-hydrocarbon, nitrogen-hydrocarbon-helium and argon-hydrocarbon refrigerant mixtures is presented in this paper.

Exergetic and thermodynamic comparison of R12 and R134a as vapour compression refrigeration working fluids

Energy Technology Data Exchange (ETDEWEB)

De Rossi, Filippo; Mastrullo, Rita; Mazzei, Pietro [Naples Univ. (Italy)

1993-05-01

A software package for both the computation of thermodynamic properties and the analysis of the usual vapour compression plant schemes is a useful tool for air conditioning and refrigeration researchers and manufacturers. At present, it could make an important contribution to the search for CFC substitutes; in fact, comparisons between two or more working fluids could be accomplished more easily. A program created by the authors is presented by means of some demonstrative diagrams referring to a comparison between the ''ozone killer'' R12 and its substitute R134a. An R134a exergy-enthalpy chart is also provided. (Author)

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

Science.gov (United States)

Akasaka, Ryo

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

Thermodynamic analysis of an absorption refrigeration system with ionic-liquid/refrigerant mixture as a working fluid

International Nuclear Information System (INIS)

Kim, Yoon Jo; Kim, Sarah; Joshi, Yogendra K.; Fedorov, Andrei G.; Kohl, Paul A.

2012-01-01

Thermodynamics of an ionic-liquid (IL) based absorption refrigeration system has been numerically analyzed. It provides an alternative to the normally toxic working fluids, such as the ammonia in conventional absorption systems. The use of ILs also eliminates crystallization and metal-compatibility problems of the water/LiBr system. Mixtures of refrigerants and imidazolium-based ILs are theoretically explored as the working fluid pairs in a miniature absorption refrigeration system, so as to utilize waste-heat to power a refrigeration/heat pump system for electronics cooling. A non-random two-liquid (NRTL) model was built and used to predict the solubility of the mixtures. Saturation temperatures at the evaporator and condenser were set at 25 °C and 50 °C, respectively, with the power dissipation of 100 W. Water in combination with [emim][BF 4 ] (1-ethyl-3-methylimidazolium tetrafluoroborate) gave the highest coefficient of performance (COP) around 0.9. The refrigerant/IL compatibility indicated by the circulation ratio, alkyl chain length of the IL, and thermodynamic properties of the refrigerants, such as latent heat of evaporation were proven to be important factors in determining the performance of the absorption system. The negative effect of high viscosity was mitigated by dilution of the IL with the refrigerant and the use of slightly larger microfluidic channel heat exchangers. -- Highlights: ► Mixtures of refrigerant/ionic-liquid are studied for absorption system. ► We carry out comprehensive theoretical thermodynamic analysis. ► The essential factors of refrigerant/IL affecting the performance are identified. ► Water/[emim][BF 4 ] showed the best performance of COP. ► The effects of high viscosity ILs on the system performance are not significant.

The effect of heat exchanger parameters on performance predictions for nonazeotropic refrigerant mixtures in liquid-liquid heat pumps

International Nuclear Information System (INIS)

Stanger, S.; Den Braven, K.R.; Owre, T.A.S.

1990-01-01

The effects of constant heat exchanger area on the coefficient of performance (COP) for liquid-liquid heat pumps were analyzed for systems which use nonazeotropic mixtures as the working fluid. For this analysis, two different computer models were compared. In the first, the log mean temperature differences (LMTDs) through the heat exchangers were specified, and were held constant for all refrigerant compositions. The second method was constructed so that the heat exchanger UA product was held constant, thus approximating constant heat exchanger area over a range of refrigerant compositions. Results from these models show only a one percent difference in COP prediction between holding LMTD constant and holding UA constant over the range of mixture composition. This paper reports the models compared using mixtures of R-22/R-11 and R-22/R-114. It is also shown that changes in glide and lift temperatures have little influence on the differences between the two models

Compressor Calorimeter Test of R-410A Alternative: R-32/134a Mixture Using a Scroll Compressor

Energy Technology Data Exchange (ETDEWEB)

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

2014-02-01

As a contribution to the AHRI Low-GWP Alternative Refrigerants Evaluation Program (AREP), this study compares the performance of lower-GWP alternative refrigerant R-32 + R-134a mixture, to that of refrigerant R-410A (baseline) in a scroll compressor designed for air-conditioning and heat pump applications. These comparisons were carried out via compressor calorimeter tests performed on a compressor designed for refrigerant R-410A and having a nominal rated capacity of 21,300 Btu/hr. Tests were conducted over a suction dew point temperature range of 10 F to 55 F in 5 F increments and a discharge dew point temperature range of 70 F to 140 F in 10 F increments. All the tests were performed with 20 F superheat, 40 F superheat, and 65 F suction temperature. A liquid subcooling level of 15 F was maintained for all the test conditions. The tests showed that the discharge temperature of the alternative refrigerant was higher than that of R-410A at all test conditions. Also, the energy efficiency ratio (EER) and cooling capacity of compressor using the alternative refrigerant were slightly lower in comparison to that of R-410A.

SIMULATION OF NON-AZEOTROPIC REFRIGERANT MIXTURES FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER WITH COUNTERCURRENT HEAT EXCHANGES

Science.gov (United States)

The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. This RF is housed in a stan...

Performance comparison of a refrigerator system using R134a and hydrocarbon refrigerant (HCR134a) with different expansion devices

Science.gov (United States)

Aziz, A.; Izzudin; Mainil, A. K.

2017-09-01

The objective of this study is to compare the performance of refrigerator system using working fluid between R134a refrigerant and HCR134a as hydrocarbon refrigerant for substitution of R134a. The use of capillary tube (CT) 1.5 m with HCR134a showed that slightly better COP than among the others, due to the lower pressure of condenser, conversely thermostatic expansion valve (TEV) showed that better COP than among the others with R134a. COP of CT 1.25 m and CT 1.5 m using HCR134a increase about 42.89% and 18.09% compared to R134a, where the electric current of refrigerator system decrease about 11.63% and 10.98%. However, the COP of HCR134a with CT 2.7 m and TEV were obtained lower than R134a about 16.2% and 17.06% and the use of electric current is higher than R134a about 12.98% and 16.5%. The use of HCR134a provides a higher refrigeration effect than R134a about 66.71%-88.27% for various types of expansion devices. The results confirmed that HCR134a could be an alternative refrigerant for replacement of R134a refrigerant.

Phase and viscosity behaviour of refrigerant-lubricant mixtures

DEFF Research Database (Denmark)

Cisneros, Sergio; Garcia, J.; Fernandez, J.

2005-01-01

, mainly as a function of the molecular asymmetry. This also has a profound effect in the mixture transport properties. Thus, in this work the general aspects of phase and viscosity behaviour linked to the type of asymmetry found in refrigerant-lubricant mixtures are discussed in the context of phase...

Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoyan [School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); Yuan, Xiuling [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

2008-11-15

Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30-50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes. (author)

Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Xiaoyan, Zhang [School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)], E-mail: gqzxy@sohu.com; Xiuling, Yuan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

2008-11-15

Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30-50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes.

Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

International Nuclear Information System (INIS)

Zhang Xiaoyan; Yuan Xiuling

2008-01-01

Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30-50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes

Correlation of refrigerant mass flow rate through adiabatic capillary tubes using mixture refrigerant carbondioxide and ethane for low temperature applications

Science.gov (United States)

Nasruddin, Syaka, Darwin R. B.; Alhamid, M. Idrus

2012-06-01

Various binary mixtures of carbon dioxide and hydrocarbons, especially propane or ethane, as alternative natural refrigerants to Chlorofluorocarbons (CFCs) or Hydro fluorocarbons (HFCs) are presented in this paper. Their environmental performance is friendly, with an ozone depletion potential (ODP) of zero and Global-warming potential (GWP) smaller than 20. The capillary tube performance for the alternative refrigerant HFC HCand mixed refrigerants have been widely studied. However, studies that discuss the performance of the capillary tube to a mixture of natural refrigerants, in particular a mixture of azeotrope carbon dioxide and ethane is still undeveloped. A method of empirical correlation to determine the mass flow rate and pipe length has an important role in the design of the capillary tube for industrial refrigeration. Based on the variables that effect the rate of mass flow of refrigerant in the capillary tube, the Buckingham Pi theorem formulated eight non-dimensional parameters to be developed into an empirical equations correlation. Furthermore, non-linear regression analysis used to determine the co-efficiency and exponent of this empirical correlation based on experimental verification of the results database.

Prediction of refrigerant absorption and onset of natural convection in lubricant oil

Energy Technology Data Exchange (ETDEWEB)

Barbosa, Jader R.; Marcelino Neto, Moises A. [Department of Mechanical Engineering, Federal University of Santa Catarina, Florianopolis, SC 88040900 (Brazil); Thoma, Stefan M. [Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology, Sonneggstrasse 3, 8092 Zurich (Switzerland)

2008-11-15

Refrigerant absorption and mixing in lubricant oil are important in the design of refrigeration compressors and refrigeration systems. Experimental work is reported on absorption of R-134a vapour through the top interface of an initially stagnant layer of pure lubricant oil. Since the liquid refrigerant is heavier than the oil, mixing is enhanced due to natural mass convection. In the present paper, the behaviour of the liquid temperature during absorption is described based on measurements carried out in a test rig consisting of a transparent 70 mm ID, 150 mm long, vertical glass tube through which absorption can be directly observed. Transient liquid temperatures were measured at three different heights in the test section (two in the vapour, one in the liquid). The experimental work is complemented by a theoretical analysis of the critical time for the onset of mass transfer induced Rayleigh instability. The model is based on a critical mass transfer Rayleigh number criterion widely reported in the literature and takes into account the variation of physical properties in the liquid layer. The critical time for the onset of natural mass convection increases with decreasing system pressure as a result of a lower equilibrium concentration at the vapour-liquid interface. (author)

Evaporation of refrigerant HFC 407C on plain tubes or at an improved surface; Evaporation du refrigerant HFC 407C sur des tubes lisses ou a surface amelioree

Energy Technology Data Exchange (ETDEWEB)

Zuercher, O.; Favrat, D.; Thome, J. R.; Kattan, N.; Nidegger, E. [Ecole polytechnique federale, Lab. d` energetique industrielle, Lausanne (Switzerland)

1996-11-15

The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requires good methods for predicting heat transfer of substitute fluids. The measurements in the LENI test facility (concentric tubes with water flowing in a counter-current flow) with HFC 407C, HFC 134a, HCFC 123, HFC 404a and HFC/HCFC 402A provide a new data bank for new refrigerants, and allow a coherent comparison with old refrigerants CFC 11, CFC 12, CFC/HCFC 502 and with existing correlations. The existing correlations were found to be inadequate. Because of this work, an improved flow pattern map and flow boiling model were developed, which resulted in a substantial progress in the accurate predict of heat transfer in plain, horizontal tubes for refrigerants without oil. The Kattan et al. correlation was programmed to calculate and compare predicted heat transfer coefficients to the new HFC 407C test data. The flow pattern map proposed by Kattan et al. was also programmed and compared to flow regimes observed for HFC 407C. It predicted the HFC 407C flow pattern data quite accurately. The original objective of the HFC 407C measurements was the validation of the Kattan et al. correlation applied to a zeotropic refrigerant blend. Local flow boiling heat transfer coefficients were measured for HFC 407C evaporating inside a microfin and a plain tube. In addition, microfin heat transfer augmentation relative to a plain tube was investigated. The presence of oil in the evaporator had a complex effect on heat transfer coefficients. Local flow boiling heat transfer coefficients were measured for refrigerant HFC 407C ester oil mixtures (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of zeotropic refrigerant blends and lubricating oils was also developed. (author) figs., tabs., 14 refs.

Studies on capillary tube expansion device used in J-T refrigerators operating with nitrogen-hydrocarbon mixtures

Science.gov (United States)

Harish Kruthiventi, S. S.; Venkatarathnam, G.

2017-10-01

Capillary tube expansion devices are used extensively in small closed cycle J-T refrigerators operating with refrigerant mixtures due to its low cost and the absence of any moving parts. It is possible for J-T refrigerators operating with mixtures that the velocity of refrigerant mixture at capillary tube outlet reaches a value where it equals the speed of sound at certain conditions. The variation of the speed of sound of nitrogen-hydrocarbon mixtures used in J-T refrigerators has been studied in two phase (vapour-liquid) and three-phase (Vapour-liquid-liquid) region as a function of temperature and pressure in this work. Also the conditions under which choking occurs in practical J-T refrigerators is investigated.

Refrigeration Cycle Design for Refrigerant Mixtures by Molecular Simulation

Czech Academy of Sciences Publication Activity Database

Smith, W.R.; Francová, Magda; Kowalski, M.; Nezbeda, Ivo

2010-01-01

Roč. 75, č. 4 (2010), s. 383-391 ISSN 0010-0765 R&D Projects: GA AV ČR IAA400720710 Grant - others:NSERC(CA) OGP1041 Institutional research plan: CEZ:AV0Z40720504 Keywords : refrigerants * molecular simulation s * vapor–liquid equilibrium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.853, year: 2010

Redesign 3 R Machine as a Refrigerant Waste Treatment Alternative in Environmental Rescue

Science.gov (United States)

Negara, I. P. S.; Arsawan, I. M.

2018-01-01

Cooling machine technologies really affect nowadays’ modern life, not only limited in enhancement of life quality and comfort, but it has also reached the essential things of humans’ life supporter (Arora, 2001). Cooling machine technologies have direct contribution toward environmental damage such as depletion of ozone layer and global warming through synthetic refrigerant waste and leakage (CFC and HFC) to environment. The refrigerant release to the environment is 60% of the service sector. Destructive characteristics of ozone possessed by CFC were first proposed by Rowland and Molina which were then supported by yard measurement. It is estimated that ozone layer damage occurs for about 3% every decade. The ozone layer located in the stratosphere is functioned to prevent ultraviolet-B ray from entering into earth surface. This Ultraviolet-B is suspected to be the cause of health problem for humans and disorder for plants on earth. As for the purpose of this research is to obtain a product design of refrigerant waste processing system (recovery and recycle refrigerant) as well as to acknowledge the work method (COP) of cooling machines that use CFC refrigerant (R-12) as the result of recovery and recycle compared to CFC refrigerant (R-12)/pure R134a. One method that can be used is by redesigning existing equipment namely 3R machine that cannot be used anymore thus it can be reused. This research will be conducted through modifying the existing 3R machine therefore it can be reused and be easily operated as well as doing the maintenance, after that the refrigerant as the result of recovery will be tried on a refrigeration system and a test of refrigeration system work method will be conducted by using the refrigerant recycle product which is obtained and compared with the work method of the one with pure refrigeration.The result has been achieved that the redesign product of refrigerant waste processing equipment can be reused and able to perform the recovery

ARTI Refrigerant Database

Energy Technology Data Exchange (ETDEWEB)

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

1993-04-30

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

Functional Dependence of Thermodynamic and Thermokinetic Parameters of Refrigerants Used in Mine Air Refrigerators. Part 1 - Refrigerant R407C

Science.gov (United States)

Nowak, Bernard; Życzkowski, Piotr; Łuczak, Rafał

2017-03-01

The authors of this article dealt with the issue of modeling the thermodynamic and thermokinetic properties (parameters) of refrigerants. The knowledge of these parameters is essential to design refrigeration equipment, to perform their energy efficiency analysis, or to compare the efficiency of air refrigerators using different refrigerants. One of the refrigerants used in mine air compression refrigerators is R407C. For this refrigerant, 23 dependencies were developed, determining its thermodynamic and thermokinetic parameters in the states of saturated liquid, dry saturated vapour, superheated vapor, subcooled liquid, and in the two-phase region. The created formulas have been presented in Tables 2, 5, 8, 10 and 12, respectively. It should be noted that the scope of application of these formulas is wider than the range of changes of that refrigerant during the normal operation of mine refrigeration equipment. The article ends with the statistical verification of the developed dependencies. For this purpose, for each model correlation coefficients and coefficients of determination were calculated, as well as absolute and relative deviations between the given values from the program REFPROP 7 (Lemmon et al., 2002) and the calculated ones. The results of these calculations have been contained in Tables 14 and 15.

2014 German refrigeration and air conditioning meeting. Proceedings

International Nuclear Information System (INIS)

2014-01-01

The proceedings of the 2014 German refrigeration and air conditioning meeting contain contributions on the following topics: cryotechnology, fundamentals and materials for the refrigeration and heat pump technology, devices and components for the refrigeration and heat pump technology, applications of refrigeration technologies, air conditioning technology and heat pump applications, cryotechnology in biology and medicine, heat transfer and ventilation, guidelines and legal topics, refrigerant fluid - oil mixtures, control and surveillance, simulation and control, ambient air.

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

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shengjun; Wang, Huaixin; Guo, Tao [Department of Thermal Energy and Refrigeration Engineering, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China)

2010-05-15

Experimental investigations were carried out on non-azeotropic refrigerant mixtures, named M1A (mass fraction of 20%R152a and 80%R245fa), M1B (mass fraction of 37% R152a and 63%R245fa) and M1C (mass fraction of 50%R152a and 50%R245fa), based on a water-to-water heat pump system in the condensing temperature range of 70-90 C with a cycle temperature lift of 45 C. Performance of R245fa was tested for comparison. Unfair factors in experimental comparative evaluation research with the same apparatus were identified and corrected. Experimental cycle performance of the mixtures were tested and compared with improved experimental assessment methodology. The results show that all of the mixtures deliver higher discharge temperature, higher heating capacity, higher COP and higher {epsilon}{sub h,c} than R245fa. M1B presents the most excellent cycle performance and is recommended as working fluid for moderate/high temperature heat pump. (author)

ARTI Refrigerant Database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1992-11-09

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

Influence of special attributes of zeotropic refrigerant mixtures on design and operation of vapour compression refrigeration and heat pump systems

International Nuclear Information System (INIS)

Rajapaksha, Leelananda

2007-01-01

The use of zeotropic refrigerant mixtures introduces a number of novel issues that affect the established design and operational practices of vapour compression systems used in refrigeration, air conditioning and heat pump applications. Two attributes; composition shift and temperature glide, associated with the phase changing process of zeotropic mixtures are the primary phenomena that bring in these issues. However, relevant researches are uncovering ways how careful system designs and selection of operational parameters allow improving the energy efficiency and the capacity of vapour compression refrigeration systems. Most of these concepts exploit the presence of composition shift and temperature glide. This paper qualitatively discusses how the mixture attributes influence the established heat exchanger design practices, performance and operation of conventional vapour compression systems. How the temperature glide and composition shift can be incorporated to improve the system performance and the efficiency are also discussed

Investigation of the effect of different refrigerants on performances of binary geothermal power plants

International Nuclear Information System (INIS)

Basaran, Anil; Ozgener, Leyla

2013-01-01

Highlights: • Working fluid selection plays a key role on binary cycle performance. • Selected refrigerants were analyzed in the sample cycle under the same working conditions. • Energy and exergy efficiencies of binary cycle were calculated for 8 refrigerants. - Abstract: The paper tries to review the argument of the use of working fluids for binary cycle power plants and has been dedicated to this specific argument with a more general perspective. Binary cycle that allows the production of electricity from geothermal energy sources is one of these systems. In this cycle, thermal energy obtained from geothermal sources is transferred to second working fluid. Therefore, selection of second working fluid plays a key role on the cycle performance. In this study, a sample geothermal binary power cycle was modeled and 12 refrigerants that are HFC, HC, and zoetrope refrigerant mixtures were selected as working fluid. Energy and exergy efficiencies of binary cycle were calculated for 12 refrigerants. Dry type fluids of investigated refrigerants R 236ea, R 600, R 600a, and R 227ea showed higher energy and exergy efficiencies, respectively. On the other hand, R 143a, R 415A, R 290, and R 413A that are wet fluids indicated lower energy and exergy efficiencies, respectively

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

Science.gov (United States)

Gurudath Nayak, H.; Venkatarathnam, G.

2009-07-01

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.

TRANSPORT PROPERTIES FOR REFRIGERANT MIXTURES

Directory of Open Access Journals (Sweden)

V. Geller

2014-06-01

Full Text Available A set of models to predict viscosity and thermal conductivity of refrigerant mixtures is developed. A general model for viscosity and thermal conductivity use the three contributions sum form (the dilute-gas terms, the residual terms, and the liquid terms. The corresponding states model is recommended to predict the dense gas transport properties over a range of reduced density from 0 to 2. It is shown that the RHS model provides the most reliable results for the saturated-liquid and the compressed-liquid transport properties over a range of given temperatures from 0,5 to 0,95.

Pilot retrofit test of refrigerant R-134a for GDSCC

Science.gov (United States)

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

1994-01-01

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

Effect of refrigeration lubricants on the heat transfer performance in the microfin tube evaporator

Energy Technology Data Exchange (ETDEWEB)

Cho, K N; Tae, S J [Sung Kyun Kwan University, Seoul (Korea)

1999-01-01

The present study experimentally investigated the defect of refrigeration lubricant on the heat transfer performance in the straight sections and U-bend of a microfin tube evaporator by using R-22/mineral oil and R-407C/POE oil. The apparatus consisted of test section with U-bend, preheater, condenser, oil injection and sampling devices, magnetic pump, mass flow meter etc. The experimental parameters were oil concentration of 0 to 5 wt%, inlet quality of 0.1 to 0.5, mass flux of 219 and 400 kg/m{sup 2}s and heat flux of 10 and 20 kw/m{sup 2}. The effects of parameters on the heat transfer coefficients were large in the order of inlet quality, mass flux and heat flux as oil concentration got increased. As oil concentration was increased, heat transfer coefficients were continuously decreased for R-22 and increased by 3% up to the concentration of 1% and then decreased for R-407C under the condition of large inlet quality, and small mass flux and heat flux. But, the heat transfer coefficients were increased up to the opposite conditions. The variation of enhancement factors for R-407C refrigerants under the opposite conditions. The variation of enhancement factors for R-407C was under 50% of that for R-22 and the variation with respect to the positions in the test section was small. The pressure drops were increased for both R-22 and R-407C refrigerants as oil concentration was increased. The pressure drops for R-407C were smaller by the maximum of 18% than those for R-22. 12 refs., 1 tab., 14 figs.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-08-01

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

Experimental investigation of HFC407C/HC290/HC600a mixture in a window air conditioner

International Nuclear Information System (INIS)

Jabaraj, D.B.; Avinash, P.; Lal, D. Mohan; Renganarayan, S.

2006-01-01

HCFC22, one of the widely used refrigerants in window air conditioners must be phased out soon as per the Montreal protocol. Presently, HFC407C is considered as a potential drop in substitute for HCFC22, but retrofitting HCFC22 systems with HFC407C with polyol ester oil (POE) is a major issue as HFC407C is immiscible with mineral oil. The miscibility issue of HFC407C with mineral oil was overcome with the addition of a HC blend to it. The above technoeconomic feasibility issues to retrofit the existing HCFC22 systems with an ozone friendly refrigerant and retain the energy efficiency of the system are challenges in the air conditioning sector. In this present work, an experimental analysis has been conducted in a window air conditioner retrofitted with eco-friendly refrigerant mixtures of HFC407C/HC290/HC600a without changing the mineral oil. Its performance, as well as energy consumption, was compared with the conventional one. It is observed that the mixtures demand lengthening of the condenser in order to maintain the discharge pressure within acceptable limits. This also resulted in better heat transfer at the condenser. Therefore, in this study, the condenser tube length was increased by 19% to suit the mixtures as compared to HCFC22. Compared to HCFC22, the refrigeration capacity of the new mixture was 9.54-12.76% higher than that of HCFC22, while the actual COP was found to be 11.91-13.24% higher than that of HCFC22. The overall performance has proved that the HFC407C/HC blend refrigerant mixture could be an eco-friendly substitute to phase out HCFC22

Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

International Nuclear Information System (INIS)

Ganni, V.; Knudsen, P.; Arenius, D.; Casagrande, F.

2014-01-01

The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system

Prediction of performance of a jet cooling system operating with pure refrigerants or non-azeotropic mixtures. Influence de la nature des fluides, purs ou en melanges non-azeotropiques, sur les performances d'une machine de climatisation a ejecto-compresseur

Energy Technology Data Exchange (ETDEWEB)

Dorantes, R; Lallemand, A [Centre National de la Recherche Scientifique (CNRS), 69 Villeurbanne (France). Centre de Thermique

1995-01-01

This paper investigates a simple model of an ejector-compression refrigeration cycle and its applications to air conditioning. The efficiency using either classical refrigerants (R11, R22, R114), other pure refrigerants (R123, R133a, R134a, R141b, R142b, R152a, RC318) or non-azeotropic mixtures is presented. The results suggest that, for different temperatures of the heat source and the heat sink, the entrainment ratio and the system efficiency depend mainly on the fluid type and the mixture composition. An exergetic analysis shows that the major part of the exergy destruction takes place in the ejector, but that the boiler and condenser exergetic losses are significant. (author)

Heat and mass transfer prediction of binary refrigerant mixtures condensing in a horizontal microfin tube

Energy Technology Data Exchange (ETDEWEB)

Koyama, Shigeru; Yu, Jian; Ishibashi, Akira

1999-07-01

In the face of the phase-out of HCFC22 for its effect on globe environment, the alternative refrigerant has been paid attention in the refrigeration and heat pump industry. In the present stage, it is found that any pure refrigerant is not a good substitute of HCFC22 for the system in use. The authors have to use binary or ternary refrigerant mixtures as the substitute to meet industrial requirement. But until now, although the heat transfer characteristics of the refrigerant mixtures can be measured in experiments and predicted in some degree, the mass transfer characteristics in condensation process, which is a main part in most systems, can not be clarified by both experimental and theoretical methods. In the present study a non-equilibrium model for condensation of binary refrigerant mixtures inside a horizontal microfin tube is proposed. In this model it is assumed that the phase equilibrium is only established at the vapor-liquid interface, while the bulk vapor and the bulk liquid are in non-equilibrium in the same cross section. The mass transfer characteristic in vapor core is obtained from the analogy between mass and momentum transfer. In the liquid layer, the mass fraction distribution is neglected, but the mass transfer coefficient is treated as infinite that can keep a finite value for the mass transfer rate in liquid phase. From the calculation results compared with the experimental ones for the condensation of HFC134a/HCFC123 and HCFC22/CFC114 mixtures, it is found that the calculated heat flux distribution along the tube axis is in good agreement with that of experiment, and the calculated values of condensing length agree well with the experimental ones. Using the present model, the local mass faction distribution, the diffusion mass transfer rate and the mass transfer characteristics in both vapor and liquid phase are demonstrated. From these results, the effect of mass transfer resistance on condensation heat transfer characteristics for binary

Analysis of ammonia/water and ammonia/salt mixture absorption cycles for refrigeration purposes in fishing ships

International Nuclear Information System (INIS)

Táboas, Francisco; Bourouis, Mahmoud; Vallès, Manel

2014-01-01

In this work, the use of waste heat energy of jacket water in diesel engines of fishing ships was analysed for use as a heat source for absorption refrigeration systems. The thermodynamic simulation of an absorption refrigeration cycle with three different working fluid mixtures that use ammonia as a refrigerant was carried out. This analysis was assessed in terms of the cooling demand and cycle performance as a function of the evaporator, condenser and generator temperatures. Moreover, the need for rectifying the vapour stream leaving the generator was analysed together with the drag of the fraction of non-evaporated liquid to the absorber. The results show that the NH 3 /(LiNO 3  + H 2 O) and NH 3 /LiNO 3 fluid mixtures have higher values of COP as compared to NH 3 /H 2 O fluid mixture, the differences being more pronounced at low generation temperatures. If the activation temperature is set to 85 °C, the minimum evaporation temperatures that can be achieved are −18.8 °C for the cycle with NH 3 /LiNO 3 , −17.5 °C for the cycle with NH 3 /(LiNO 3  + H 2 O) cycle and −13.7 °C for the NH 3 /H 2 O cycle at a condensing temperature of 25 °C. Also, for the NH 3 /(LiNO 3  + H 2 O) fluid mixture, it has been demonstrated that the absorption refrigeration cycle can be operated without a distillation column and in this case the water content in the refrigerant stream entering the evaporator is less than 1.5% in weight at the operating conditions selected. - Highlights: •Ammonia absorption systems can provide refrigeration necessities for fishing ships. •Absorption refrigeration systems reduce the energy consumption of fishing ships. •The NH 3 /(LiNO 3  + H 2 O) mixture is recommended for absorption refrigeration cycles

Effect-directed analysis and mixture effects of AhR-active PAHs in crude oil and coastal sediments contaminated by the Hebei Spirit oil spill

International Nuclear Information System (INIS)

Hong, Seongjin; Lee, Sangwoo; Choi, Kyungho; Kim, Gi Beum; Ha, Sung Yong; Kwon, Bong-Oh; Ryu, Jongseong; Yim, Un Hyuk; Shim, Won Joon; Jung, Jinho; Giesy, John P.; Khim, Jong Seong

2015-01-01

The major AhR-active PAHs were identified in crude oil and oil-contaminated sediments by use of effect-directed analysis. As part of the study, an enhanced potency balance analysis was conducted by establishing the novel relative potency values of (alkyl)-PAHs from the H4IIE-luc bioassay. Silica gel column fractionation of crude oil resulted in greater AhR-mediated potencies in fractions of aromatics (F2) and resins (F3), and such trend was also observed for field collected sediment samples. AhR-mediated potencies of six F2 sub-fractions from HPLC indicated that the majority of F2 responses were attributable to 3–4 ring aromatics. Target PAHs including C4-phenanthrene, C1-chrysene, and C3-chrysene in sediments explained ∼18% of the bioassay-derived TCDD-EQs, however, the unknown AhR agonists and potential mixture effects remain in question. Overall, the AhR-potency and antagonistic potential of residual oil in sediment tended to decrease over time, thus monitoring of weathering process would be key for the post management of oil-contaminated sites. - Highlights: • AhR-active PAHs in crude oil and sediments were newly determined using EDA. • Novel relative potency values of (alkyl)-PAHs for AhR activity were established. • Three to four ring PAHs were identified to be major AhR agonists in crude oil. • Parent and alkyl-PAHs explained ∼18% of the total AhR-mediated potencies of crude oil. • AhR-mediated potencies apparently decreased by the timely weathering processes. - “Major AhR agonists were identified three to four ring PAHs in crude oil and sediments determined by use of effect-directed analysis.”

Theoretical analysis of a combined power and ejector refrigeration cycle using zeotropic mixture

International Nuclear Information System (INIS)

Yang, Xingyang; Zhao, Li; Li, Hailong; Yu, Zhixin

2015-01-01

Highlights: • A combined power and refrigeration cycle using zeotropic mixture is analyzed. • The cycle performances with different mixture compositions are compared. • Both exergy and parametric analysis of the combined cycle are conducted. - Abstract: A theoretical study on a combined power and ejector refrigeration cycle using zeotropic mixture isobutane/pentane is carried out. The performances of different mixture compositions are compared. An exergy analysis is conducted for the cycle. The result reveals that most exergy destruction happens in the ejector, where more than 40% exergy is lost. The heat exchange in generator causes the second largest exergy loss, larger than 28%. As the mass fraction of isobutane changes ranges from 100% to 0%, the relative exergy destruction of each component is also changing. And mixture isobutane/pentane (50/50) has the maximum exergy efficiency of 7.83%. The parametric analysis of generator temperature, condenser temperature and evaporator temperature for all the mixtures shows that, all these three thermodynamic parameters have a strong effect on the cycle performance.

TESTING OF REFRIGERANT MIXTURES IN RESIDENTIAL HEAT PUMPS

Science.gov (United States)

The report gives results of an investigation of four possibilities for replacing Hydrochlorofluorocarbon-22 (HCFC-22) with the non-ozone-depleting new refrigerants R-407D and R-407C in residential heat pumps. The first and simplest scenario was a retrofit with no hardware modific...

2014 German refrigeration and air conditioning meeting. Proceedings; Deutsche Kaelte- und Klimatagung 2014. Tagungsbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

2014-07-01

The proceedings of the 2014 German refrigeration and air conditioning meeting contain contributions on the following topics: cryotechnology, fundamentals and materials for the refrigeration and heat pump technology, devices and components for the refrigeration and heat pump technology, applications of refrigeration technologies, air conditioning technology and heat pump applications, cryotechnology in biology and medicine, heat transfer and ventilation, guidelines and legal topics, refrigerant fluid - oil mixtures, control and surveillance, simulation and control, ambient air.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Directory of Open Access Journals (Sweden)

Mishra Shubham

2016-12-01

Full Text Available Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%, which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle. Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Science.gov (United States)

Mishra, Shubham; Sarkar, Jahar

2016-12-01

Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene) is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP) for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%), which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle). Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Caracterización de los aceites de refrigeración utilizados en motocompresores herméticos que trabajan con el gas refrigerante LB-12

Directory of Open Access Journals (Sweden)

Celestino Oro Ortiz

2011-03-01

Full Text Available El objetivo de este trabajo va dirigido a conocer las principales propiedades de los aceites de refrigeración de formulaciónnacional y extranjera concebidos para los sistemas que trabajan con el refrigerante R-12 y en la actualidad se utilizancon el gas refrigerante LB-12. Se realizó un análisis de laboratorio a los aceites estudiados según las normas de laASTM para los productos derivados del petróleo. Los resultados de este trabajo son de interés para la correctaselección del aceite de refrigeración atendiendo al modelo de compresor, refrigerante utilizado y condiciones deexplotación.  The use of the hydrocarbons as refrigerants in actuality have been a great diffusion in the hermetic motocompressorsof domestic refrigerators and other, in substitution of the R-12 refrigerant which result harmful to the ozone layer. Theobjective of this research was to know the principal properties of the refrigeration oils of national and foreign formulationmarketed for the refrigeration systems that work with the refrigerant R-12 and in the nowadays are using the refrigerantgas LB-12. In this work was made laboratories analysis to the oil using the ASTM norms for the oil products. Theresults of this work are interesting for the suitable selection of the refrigeration oil it must be taken into accountmotocompressor model, refrigerant used, and exploitation conditions.

Prediction of vapour-liquid and vapour-liquid-liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators

Science.gov (United States)

Narayanan, Vineed; Venkatarathnam, G.

2018-03-01

Nitrogen-hydrocarbon mixtures are widely used as refrigerants in J-T refrigerators operating with mixtures, as well as in natural gas liquefiers. The Peng-Robinson equation of state has traditionally been used to simulate the above cryogenic process. Multi parameter Helmholtz energy equations are now preferred for determining the properties of natural gas. They have, however, been used only to predict vapour-liquid equilibria, and not vapour-liquid-liquid equilibria that can occur in mixtures used in cryogenic mixed refrigerant processes. In this paper the vapour-liquid equilibrium of binary mixtures of nitrogen-methane, nitrogen-ethane, nitrogen-propane, nitrogen-isobutane and three component mixtures of nitrogen-methane-ethane and nitrogen-methane-propane have been studied with the Peng-Robinson and the Helmholtz energy equations of state of NIST REFPROP and compared with experimental data available in the literature.

Petroleum Diesel Fuel and Linseed Oil Mixtures as Engine Fuels

Science.gov (United States)

Markov, V. A.; Kamaltdinov, V. G.; Savastenko, A. A.

2018-01-01

The actual problem is the use of alternative biofuels in automotive diesel engines. Insufficiently studied are the indicators of toxicity of exhaust gases of these engines operating on biofuel. The aim of the study is to identify indicators of the toxicity of exhaust gases when using of petroleum diesel fuel and linseed oil mixtures as a fuel for automotive diesel engines. Physical and chemical properties of linseed oil and its mixtures with petroleum diesel fuel are considered. Experimental researches of D-245.12C diesel are carried out on mixtures of diesel fuel and corn oil with a different composition. An opportunity of exhaust toxicity indexes improvement using these mixtures as a fuel for automobiles engine is shown.

Flow boiling heat transfer coefficients at cryogenic temperatures for multi-component refrigerant mixtures of nitrogen-hydrocarbons

Science.gov (United States)

Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

2014-01-01

The recuperative heat exchanger governs the overall performance of the mixed refrigerant Joule-Thomson cryocooler. In these heat exchangers, the non-azeotropic refrigerant mixture of nitrogen-hydrocarbons undergoes boiling and condensation simultaneously at cryogenic temperature. Hence, the design of such heat exchanger is crucial. However, due to lack of empirical correlations to predict two-phase heat transfer coefficients of multi-component mixtures at low temperature, the design of such heat exchanger is difficult.

Development of Reference Equations of State for Refrigerant Mixtures Including Hydrocarbons

Science.gov (United States)

Miyamoto, Hiroyuki; Watanabe, Koichi

In recent years, most accurate equations of state for alternative refrigerants and their mixtures can easily be used via convenient software package, e.g., REFPROP. In the present paper, we described the current state-of-the-art equations of state for refrigerant mixtures including hydrocarbons as components. Throughout our discussion, the limitation of the available experimental data and the necessity of the improvement against the arbitrary fitting of recent modeling were confirmed. The enough number of reliable experimental data, especially for properties in the higher pressures and temperatures and for derived properties, should be accumulated in the near future for the development of the physically-sound theoretical background. The present review argued about the possibility of the progress for the future thermodynamic property modeling throughout the detailed discussion regarding the several types of the equations of state as well as the recent innovative measurement technique.

Energy and exergy analysis of a new ejector enhanced auto-cascade refrigeration cycle

International Nuclear Information System (INIS)

Yan, Gang; Chen, Jiaheng; Yu, Jianlin

2015-01-01

Highlights: • A new ejector enhanced auto-cascade refrigeration cycle using R134a/R23 is proposed. • The performance of new and basic cycles is compared by simulation method. • The new cycle outperforms the basic cycle in both energetic and exergy aspects. • Both cycles have optimum mixture compositions to obtain optimal performance. - Abstract: A new ejector enhanced auto-cascade refrigeration cycle using R134a/R23 refrigerant mixture is proposed in this paper. In the new cycle, an ejector is used to recover part of the work that would otherwise be lost in the throttling processes. The performance comparison between the new cycle and a basic auto-cascade refrigeration cycle is carried out based on the first and second laws of thermodynamics. The simulation results show that both the coefficient of performance and exergy efficiency of the new cycle can be improved by 8.42–18.02% compared with those of the basic cycle at the same operation conditions as the ejector has achieved pressure lift ratios of 1.12–1.23. It is found that in the new cycle, the highest exergy destruction occurs in the compressor followed by the condenser, cascade condenser, expansion valve, ejector and evaporator. The effect of some main parameters on the cycle performance is further investigated. The results show that for the new cycle, the achieved performance improvement over the basic cycle is also dependent on the mixture composition and the vapor quality at the condenser outlet. The coefficient of performance improvement of the new cycle over the basic cycle degrades with increasing vapor quality. In addition, there exists an optimum mixture composition to obtain the maximum coefficient of performance for the new cycle when other operation conditions are given. The optimum mixture composition of both cycles may be fixed at about 0.5 under the given evaporating temperature.

Vapor-liquid critical surface of ternary difluoromethane + pentafluoroethane + 1,1,1,2-tetrafluoroethane (R-32/125/134a) mixtures

Energy Technology Data Exchange (ETDEWEB)

Higashi, Y.

1999-09-01

The plane of vapor-liquid criticality for ternary refrigerant mixtures of difluoromethane (R-32) + pentafluoroethane (R-125) + 1,1,1,2-tetrafluoroethane (R-134a) was determined from data on the vapor-liquid coexistence curve near the mixture critical points. The composition (mass percentage) of the mixtures studied were 23% R-32 + 25% R-125 + 52% R-134a (R-407C). 25% R-32 + 15% R-125 + 60% R-134a (R-407E), and 20% R-32 + 40% R-125 + 40% R-134a (R-407A). The critical temperature of each mixture was determined by observation of the disappearance of the meniscus. The critical density of each mixture was determined on the basis of meniscus disappearance level and the intensity of the critical opalescence. The uncertainties of the temperature, density, and composition measurements are estimated as {+-}10mK, {+-}5kg{center_dot}m{sup {minus}3}, and {+-}0.05%, respectively. In addition, predictive methods for the critical parameters of R-32/125/134a mixtures are discussed.

The use of TiO2 nanoparticles to reduce refrigerator ir-reversibility

International Nuclear Information System (INIS)

Padmanabhan, Venkataramana Murthy V.; Palanisamy, Senthilkumar

2012-01-01

Highlights: ► COP of hydrocarbons mixture VCRSs increases less when compared to R134a. ► Compressor ir-reversibility of VCRSs decreases by 33% (R134a), 14% (R436A and R436B). ► Total ir-reversibility of selected VCRSs decreases. ► Exergy efficiency of R134a is exceptionally low at lower reference temperature. ► Exergy efficiency of selected VCRSs increases. - Abstract: The ir-reversibility at the process of a vapour-compression refrigeration system (VCRS) with nanoparticles in the working fluid was investigated experimentally. Mineral oil (MO) with 0.1 g L −1 TiO 2 nanoparticles mixture were used as the lubricant instead of Polyol-ester (POE) oil in the R134a, R436A (R290/R600a-56/44-wt.%) and R436B (R290/R600a-52/48-wt.%)VCRSs. The VCRS ir-reversibility at the process with the nanoparticles was investigated using second law of thermodynamics. The results indicate that R134a, R436A and R436B and MO with TiO 2 nanoparticles work normally and safely in the VCRS. The VCRSs total ir-reversibility (529, 588 and 570 W) at different process was better than the R134a, R436A and R436B and POE oil system (777, 697 and 683 W). The same tests with Al 2 O 3 nanoparticles showed that the different nanoparticles properties have little effect on the VCRS ir-reversibility. Thus, TiO 2 nanoparticles can be used in VCRS with reciprocating compressor to considerably reduce ir-reversibility at the process.

Effect of evaporator temperature on vapor compression refrigeration system

Directory of Open Access Journals (Sweden)

Abdullah A.A.A. Al-Rashed

2011-12-01

Full Text Available This paper presents a comparable evaluation of R600a (isobutane, R290 (propane, R134a, R22, for R410A, and R32 an optimized finned-tube evaporator, and analyzes the evaporator effect on the system coefficient of performance (COP. Results concerning the response of a refrigeration system simulation software to an increase in the amount of oil flowing with the refrigerant are presented. It is shown that there is optima of the apparent overheat value, for which either the exchanged heat or the refrigeration coefficient of performance (COP is maximized: consequently, it is not possible to optimize both the refrigeration COP and the evaporator effect. The obtained evaporator optimization results were incorporated in a conventional analysis of the vapor compression system. For a theoretical cycle analysis without accounting for evaporator effects, the COP spread for the studied refrigerants was as high as 11.7%. For cycle simulations including evaporator effects, the COP of R290 was better than that of R22 by up to 3.5%, while the remaining refrigerants performed approximately within a 2% COP band of the R22 baseline for the two condensing temperatures considered.

Condensing heat transfer characteristics of hydrocarbon refrigerants in 9.52 and 12.7 mm smooth tube

Science.gov (United States)

Yoon, Jung-In; Lee, Ho-Saeng; Lee, Kwang-Bae; Kim, Jae-Dol; Bansal, Pradeep

2005-12-01

Experimental results for heat transfer characteristic and pressure gradients of hydrocarbon (HC) refrigerants and R-22 during condensing inside horizontal double pipe heat exchangers are presented. The test sections which have one tube diameter of 12.70 mm with 0.86 mm wall thickness, another tube diameter of 9.52 mm with 0.76 mm wall thickness are used for this investigation. The local condensing heat transfer coefficients of HC refrigerants were higher than that of R-22. The average condensing heat transfer coefficient increased with the increase of the mass flux. It showed the higher values in HC refrigerants than R-22. Comparing the heat transfer coefficient of experimental results with that of other correlations, the presented results had a good agreement with most of the Cavallini’s correlations.

Experimental investigation of a two-step transport refrigerator with R744; Experimentelle Untersuchung einer zweistufigen Trans-portkaelteanlage mit R744

Energy Technology Data Exchange (ETDEWEB)

Moehlenkamp, A.; Lemke, N.; Koehler, J. [TU Braunschweig (Germany). Inst. fuer Thermodynamik

2012-07-01

Until now, predominantly closed, single-stage refrigeration cycles are used in the transport refrigeration. Two-stage cooling circuits facilitate new circuit variations and result in a significant increase in the energy efficiency in comparison to single-stage refrigeration cycles. This is especially true for the natural refrigerant R744 (carbon dioxide). Due to the thermodynamic features in the range of transport refrigeration R744 provides an alternative to the predominantly used synthetic refrigerants R404A and R410A with an enhanced global warming potential.The authors of the contribution under consideration report on a two-stage laboratory system which enables experimental investigations of transport refrigeration and is operated with the coolant R744. This two-stage laboratory system with an internal heat exchanger on a medium-pressure level continuously supplies coldness for normal refrigeration and deep-freezing. The design of the laboratory plant is based on a reference system for motor vehicles and thus corresponds to the practical conditions. First experimental results at an ambient temperature of 30 Celsius are presented and discussed.

THE RESULTS OF THE STUDY BOILING POINT OUT OZONE-SAFE REFRIGERANT R410A IN THE EVAPORATORS OF REFRIGERATING MACHINES

Directory of Open Access Journals (Sweden)

V. G. Bukin

2012-01-01

Full Text Available The results of experimental research boiling heat transfer of ozone-friendly R410A refrigerant in evaporators machines and the possibility of its use in place of the prohibited refrigerant R22.

Design of refrigeration system using refrigerant R134a for macro compartment

Science.gov (United States)

Rani, M. F. H.; Razlan, Z. M.; Shahriman, A. B.; Yong, C. K.; Harun, A.; Hashim, M. S. M.; Faizi, M. K.; Ibrahim, I.; Kamarrudin, N. S.; Saad, M. A. M.; Zunaidi, I.; Wan, W. K.; Desa, H.

2017-10-01

The main objective of this study is to analyse and design an optimum cooling system for macro compartment. Current product of the refrigerator is not specified for single function and not compact in size. Hence, a refrigeration system using refrigerant R134a is aimed to provide instant cooling in a macro compartment with sizing about 150 × 150 × 250 mm. The macro compartment is purposely designed to fit a bottle or drink can, which is then cooled to a desired drinking temperature of about 8°C within a period of 1 minute. The study is not only concerned with analysing of heat load of the macro compartment containing drink can, but also focused on determining suitable heat exchanger volume for both evaporator and condenser, calculating compressor displacement value and computing suitable resistance value of the expansion valve. Method of optimization is used to obtain the best solution of the problem. Mollier diagram is necessary in the process of developing the refrigeration system. Selection of blower is made properly to allow air circulation and to increase the flow rate for higher heat transfer rate. Property data are taken precisely from thermodynamic property tables. As the main four components, namely condenser, compressor, evaporator and expansion valve are fully developed, the refrigeration system is complete.

Taguchi Method for Development of Mass Flow Rate Correlation Using Hydrocarbon Refrigerant Mixture in Capillary Tube

OpenAIRE

Sulaimon, Shodiya; Nasution, Henry; Aziz, Azhar Abdul; Abdul-Rahman, Abdul-Halim; Darus, Amer N

2014-01-01

The capillary tube is an important control device used in small vapor compression refrigeration systems such as window air-conditioners, household refrigerators and freezers. This paper develops a non-dimensional correlation based on the test results of the adiabatic capillary tube for the mass flow rate through the tube using a hydrocarbon refrigerant mixture of 89.3% propane and 10.7% butane (HCM). The Taguchi method, a statistical experimental design approach, was employed. This approach e...

Exergy analysis of scroll compressors working with R22, R407C, and R417A as refrigerant for HVAC system

Directory of Open Access Journals (Sweden)

Kalaiselvam Sivakumar

2009-01-01

Full Text Available The rise in crisis of power enthralls the world economically and the options for conventional and non-conventional energy resources have been searched out. No system exists in this world with 100% efficiency due to several irreversibility's. If the output obtained from the system is maximum for a given input, maximum amount of energy can be saved globally. To understand the thermodynamic losses occurring in the system and to predict the available energy that can be tapped from the system, exergy plays a major role. Experimental study on exergy in a system can pave the way to understand the complete behavior of the system exergually. Conceptually exergy studies are based on simulation, to provide a new dimension to the concept of exergy experimental validation have been promoted. The analogy of exergy analysis of three refrigerants working in scroll compressors and their exergual features are explained in this paper. The refrigerants R22, R417A, and R407C and their thermo dynamical behavior, irreversibility were experimented in an air conditioning system with three scroll compressors, interaction between the system and the refrigerant in terms of pressure drop and heat transfer, friction has been implemented for the calculation of exergy. The entire system performance on the basis of refrigerant is validated in each part of the air conditioning system. The resultant coefficient of performance of R407C is 2.41% less than R22 in a R22 designed scroll compressor with minimal exergy losses. The second law efficiency of 50 to 55% obtained in R22 has fewer rules over R407C and R417A which has 48 to 52%. The diminutive deviation of results encourages R417A refrigerant to be used as a substitute for R22. Thus the exergual prediction of performance of refrigerant and second law efficiency can identify the use of eco-friendly refrigerant in scroll compressor.

Hydroprocesssing of light gas oil - rape oil mixtures

Energy Technology Data Exchange (ETDEWEB)

Walendziewski, Jerzy; Stolarski, Marek; Luzny, Rafal; Klimek, Bartlomiej [Faculty of Chemistry, Wroclaw University of Technology, ul. Gdanska 7/9, 50-310 Wroclaw (Poland)

2009-05-15

Two series of experiments of hydroprocessing of light gas oil - rape oil mixtures were carried out. The reactor feed was composed of raw material: first series - 10 wt.% rape oil and 90 wt.% of diesel oil; second series - 20 wt.% rape oil and 80 wt.% of diesel oil. Hydroprocessing of both mixtures was performed with the same parameter sets, temperature (320, 350 and 380 C), hydrogen pressure 3 and 5 MPa, LHSV = 2 h{sup -} {sup 1} and hydrogen feed ratio of 500 Nm{sup 3}/m{sup 3}. It was stated that within limited range it is possible to control vegetable oil hydrogenolysis in the presence of light gas oil fraction (diesel oil boiling range) through the proper selection of the process parameters. Hydrogenolysis of ester bonds and hydrogenation of olefinic bonds in vegetable oils are the main reactions in the process. Basic physicochemical properties of the obtained hydroprocessed products are presented. (author)

Cooling performance of R510A in domestic water purifiers

International Nuclear Information System (INIS)

Park, Ki Jung; Lee, Yo Han; Jung, Dong Soo

2010-01-01

Cooling performance of R510A is examined both numerically and experimentally in an effort to replace HFC134a in the refrigeration system of domestic water purifiers. Although the use of HFC134a is currently dominant, it is being phased out in Europe and most developed countries due to its high potential contribution to global warming. To solve this problem, cycle simulation and experimental measurements are conducted with a new refrigerant mixture of 88%RE170/12%R600a using actual domestic water purifiers. This mixture has been recently numbered and listed as R510A by ASHRAE. Test results show that, due to the small internal volume of the refrigeration system of the domestic water purifiers, system performance with R510A is greatly influenced by the amount of charge. With the optimum charge amount of 20 to 21 g, approximately 50% that of HFC134a, the energy consumption of R510A is 22.3% lower than that of HFC134a. The compressor discharge temperature of R510A is 3.7 .deg. C lower than that of HFC134a at the optimum charge. Overall, R510A, a new, long term, and environmentally safe refrigerant, is a good alternative for HFC134a. Furthermore, it requires only minor changes in the refrigeration system of the domestic water purifiers

48 CFR 52.223-12 - Refrigeration Equipment and Air Conditioners.

Science.gov (United States)

2010-10-01

... and Air Conditioners. 52.223-12 Section 52.223-12 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.223-12 Refrigeration Equipment and Air Conditioners. As prescribed in 23.804(b), insert the following clause: Refrigeration Equipment and Air Conditioners (MAY 1995) The Contractor shall...

Performance Analysis of Joule-Thomson Cooler Supplied with Gas Mixtures

Science.gov (United States)

Piotrowska, A.; Chorowski, M.; Dorosz, P.

2017-02-01

Joule-Thomson (J-T) cryo-coolers working in closed cycles and supplied with gas mixtures are the subject of intensive research in different laboratories. The replacement of pure nitrogen by nitrogen-hydrocarbon mixtures allows to improve both thermodynamic parameters and economy of the refrigerators. It is possible to avoid high pressures in the heat exchanger and to use standard refrigeration compressor instead of gas bottles or high-pressure oil free compressor. Closed cycle and mixture filled Joule-Thomson cryogenic refrigerator providing 10-20 W of cooling power at temperature range 90-100 K has been designed and manufactured. Thermodynamic analysis including the optimization of the cryo-cooler mixture has been performed with ASPEN HYSYS software. The paper describes the design of the cryo-cooler and provides thermodynamic analysis of the system. The test results are presented and discussed.

Cryogenic mixed refrigerant processes

CERN Document Server

Venkatarathnam, Gadhiraju

2010-01-01

Teaches the need for refrigerant mixtures, the type of mixtures that can be used for different refrigeration and liquefaction applications, the different processes that can be used and the methods to be adopted for choosing the components of a mixture and their concentration for different applications.

Estimation of performance of a J-T refrigerators operating with nitrogen-hydrocarbon mixtures and a coiled tubes-in-tube heat exchanger

Science.gov (United States)

Satya Meher, R.; Venkatarathnam, G.

2018-06-01

The exergy efficiency of Joule-Thomson (J-T) refrigerators operating with mixtures (MRC systems) strongly depends on the choice of refrigerant mixture and the performance of the heat exchanger used. Helically coiled, multiple tubes-in-tube heat exchangers with an effectiveness of over 96% are widely used in these types of systems. All the current studies focus only on the different heat transfer correlations and the uncertainty in predicting performance of the heat exchanger alone. The main focus of this work is to estimate the uncertainty in cooling capacity when the homogenous model is used by comparing the theoretical and experimental studies. The comparisons have been extended to some two-phase models present in the literature as well. Experiments have been carried out on a J-T refrigerator at a fixed heat load of 10 W with different nitrogen-hydrocarbon mixtures in the evaporator temperature range of 100-120 K. Different heat transfer models have been used to predict the temperature profiles as well as the cooling capacity of the refrigerator. The results show that the homogenous two-phase flow model is probably the most suitable model for rating the cooling capacity of a J-T refrigerator operating with nitrogen-hydrocarbon mixtures.

21 CFR 102.37 - Mixtures of edible fat or oil and olive oil.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Mixtures of edible fat or oil and olive oil. 102... for Specific Nonstandardized Foods § 102.37 Mixtures of edible fat or oil and olive oil. The common or usual name of a mixture of edible fats and oils containing less than 100 percent and more than 0 percent...

The design and development of an oil-free compressor for Spacelab Refrigerator/Freezer

Science.gov (United States)

Hye, A.

1984-01-01

Design features and test results of an oil-free compressor developed for Spacelab Mission-4 Refrigerator/Freezer are detailed. The compressor has four identical pistons activated by a common eccentric shaft, operated by a brushless dc motor at 1300 rpm. The stroke of each piston is 0.28 cm, with the piston ends connected to the shaft by means of sealed needle bearings, eliminating the ned for oil. The mass flow rates produced by the compressor are by over 100 percent higher compared to the original Amfridge unit. Test results show that the compressor can meet the Spacelab refrigerator/freezer requirements.

R-32 As An Alternative To Ammonia In Industrial Refrigeration

OpenAIRE

Pearson, Andy

2016-01-01

Ammonia is recognised to be the most commonly used refrigerant in industrial systems however it is limited in some applications by its toxicity. Â R-32 has similar flammability characteristics and a similar pressure-temperature relationship, and through its use as a blend component it has become widely used and readily available. Â This paper compares and contrasts ammonia and R-32 with specific reference to industrial applications. Â The analysis includes comparison of refrigerating effect, ...

FY1995 study of thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipments; 1995 nendo Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsurikigaku seishitsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

A hydrochlorofluorocarbon (HCFC) refrigerant, R-22, is currently being used almost exclusively as a refrigerant for conventional air-conditioning equipments. Since HCFCs are expected to be banned shortly, it is considered a crucial issue to support R and D of the air-conditioning system Lorentz-cycled with hydrofluorocarbon (HFC) refrigerants mixtures. In the present research project, therefore, it is aimed to reveal some of the essential thermodynamic properties of HFC refrigerant mixtures systematically. On the basis of a series of achievements for the last several years by the present research coordinator and his group regarding thermodynamic properties of single-component and blended HFC refrigerants, we have conducted following three major research programs rather systematically on which no challenges have ever been reported worldwide. Throughout a series of experimental as well as analytical researches performed so as to meet the objectives mentioned above, some novel knowledge and valuable outcomes could be obtained in the present study. (1) Precise measurements of vapor-liquid equilibrium properties with simultaneous determination of densities, latent heats of vaporization, and isobaric specific heat capacities in liquid phase. (2) Analytical studies to establish thermodynamic property modeling. (3) Feasibility study of evaluating the Lorentz-cycled performance. (NEDO)

Efficacy of pretreating oil palm fronds with an acid-base mixture catalyst.

Science.gov (United States)

Jung, Young Hoon; Park, Hyun Min; Park, Yong-Cheol; Park, Kyungmoon; Kim, Kyoung Heon

2017-07-01

Oil palm fronds are abundant but recalcitrant to chemical pretreatment. Herein, an acid-base mixture was applied as a catalyst to efficiently pretreat oil palm fronds. Optimized conditions for the pretreatment were a 0.1M acidic acid-base mixture and 3min ramping to 190°C and 12min holding. The oil palm fronds pretreated and washed with the acid-base mixture exhibited an enzymatic digestibility of 85% by 15 FPU Accellerase 1000/g glucan after 72h hydrolysis, which was significantly higher than the enzymatic digestibilities obtained by acid or alkali pretreatment alone. This could be attributed to the synergistic actions of the acid and base, producing an 87% glucose recovery with 100% and 40.3% removal of xylan and lignin, respectively, from the solids. Therefore, an acid-base mixture can be a feasible catalyst to deconstruct oil palm fronds for sugar production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Composition shift in liquid-recirculation refrigerating systems: an experimental investigation for the pure fluid R134a and the mixture R32/134a

Energy Technology Data Exchange (ETDEWEB)

Giuliani, G.; Marchesi Donati, F.; Polonara, F. [Ancona Univ. (Italy). Dip. di Energetica; Hewitt, N.J. [University of Ulster at Coleraine, Northern Ireland (United Kingdom). NICERT

1999-09-01

The ability of zeotropic mixtures with a remarkable temperature glide to operate in liquid-recirculation systems is investigated and the results of an experimental comparison between the performances of the pure fluid R134a and the zeotropic mixture R32/134a (25/75% by mass) are presented. R134a performs slightly better in the liquid-recirculation mode than in the traditional dry-expansion mode; on the other hand, liquid-recirculation configuration has a detrimental effect on the zeotropic mixture's performance. The reason for this detrimental effect is the mixture component separation which occurs at the liquid/vapor separator. The effect of this separation is investigated using gas chromatograph analysis.

Fermilab satellite refrigerator compressors with the oil- and moisture-removal systems

International Nuclear Information System (INIS)

Satti, J.A.; Andrews, R.A.

1983-08-01

We have designed and tested a helium purification system for the Energy Doubler and the experimental areas. A purification system is installed after each screw compressor in the satellite refrigerators. The purification system removes oil mist, oil vapor, water vapor, and particulate from the compressed helium. The units were designed with consideration of modularity and necessary redundancy (i.e., guard purification). Test results which led to the final configuration are presented, along with achieved performance of the oil removal in the operating system

Experimental evaluation of R448A as R404A lower-GWP alternative in refrigeration systems

International Nuclear Information System (INIS)

Mota-Babiloni, Adrián; Navarro-Esbrí, Joaquín; Peris, Bernardo; Molés, Francisco; Verdú, Gumersindo

2015-01-01

Highlights: • R448A (GWP = 1273) is an A1 refrigerant proposed in DX supermarket refrigeration systems. • Performance of R448A and R404A is evaluated under different conditions. • R448A presents lower cooling capacity but higher COP than R404A. • The R448A maximum discharge temperature is always below 380 K. • R448A is more interesting at high condensing (ambient) temperatures. - Abstract: Due to the adoption of EU Regulation No 517/2014, R404A is going to be banned in Europe in most of refrigeration applications, in which is typically used, due to its very high GWP value, 3943. In this paper an experimental comparison between R404A and R448A, a non-flammable alternative with GWP of 1390, is presented. The experimental tests are intended to simulate typical freezing and conservation temperatures and different condensing conditions. Despite cooling capacity of R448A is slightly below that of R404A, R448A energy consumption is even smaller; and R448A COP is higher than that obtained using R404A. Hence, it can be concluded that R448A could be an energy efficient alternative to R404A with a GWP reduction of 70%. Compressor discharge temperature remains at non-dangerous levels.

Thermodynamic and heat transfer analyses for R1234yf and R1234ze(E) as drop-in replacements for R134a in a small power refrigerating system

International Nuclear Information System (INIS)

Janković, Zvonimir; Sieres Atienza, Jaime; Martínez Suárez, José Antonio

2015-01-01

In this paper we present two different analyses of R1234yf and R1234ze(E) as drop-in replacements for R134a in a small power refrigeration system. The first analysis is based on equal evaporation and condensation temperatures before and after the refrigerant replacement. The second analysis is carried out for equal cooling medium conditions in the condenser, so that the transport properties and the heat transfer features in the condenser are considered for the three refrigerants. In order to perform the analyses, a simulation model was developed, that takes into account specific data, characteristics and dimensions of the main components of a small power refrigeration system. The model was validated with experimental data for R134a and later used to predict the behavior with R1234yf and R1234ze(E). Results show that different conclusions may be drawn if the drop-in analysis is carried out for equal condensation temperatures or for equal temperatures of the cooling medium in the condenser, as well as that these results are affected by the condenser design. In general, R1234yf seems as an adequate drop-in refrigerant for R134a, but R1234ze(E) may perform better when an overridden compressor can be used to match the refrigerating system cooling power. - Highlights: • Low GWP refrigerants R1234yf and R1234ze(E) are potential replacements for R134a. • Refrigerating system mathematical model to predict drop-in performance. • Drop-in analysis for the same evaporation and condensation temperatures. • Drop-in analysis for the same cooling medium temperatures. • Refrigerant heat transfer features have a great impact on the drop-in performance

Experimental evaluation of desuperheating and oil cooling process through liquid injection in two-staged ammonia refrigeration systems with screw compressors

International Nuclear Information System (INIS)

Zlatanović, Ivan; Rudonja, Nedžad

2012-01-01

This paper examines the problem of achieving desuperheating through liquid injection in two-staged refrigeration systems based on screw compressors. The oil cooling process by refrigerant injection is also included. The basic thermodynamic principles of desuperheating and compressor cooling as well as short comparison with traditional method with a thermosyphon system have also been presented. Finally, the collected data referring to a big refrigeration plant are analyzed in the paper. Specific ammonia system concept applied in this refrigeration plant has demonstrated its advantages and disadvantages. - Highlights: ► An experiment was setup during a frozen food factory refrigeration system reconstruction and adaptation. ► Desuperheating and low-stage compressors oil cooling process were investigated. ► Efficiency of compression process and high-stage compressors functioning were examined. ► Evaporation temperature reduction has great influence on the need for injected liquid refrigerant. ► Several cases in which desuperheating and oil cooling process application are justified were determined.

Flow Boiling of Pure and Oil Contaminated Carbon Dioxide as Refrigerant

DEFF Research Database (Denmark)

Mohamed, A.-R. Mohamed

2003-01-01

of benefit of the environment. The main challenge for CO2 based refrigerant systems is to increase the performance of the heat exchangers. Especially there is a need for information concerning heat transfer and pressure drop in evaporator and condenser with CO2 as refrigerant. The reason this is the very...... to 40 kW/m2 and evaporation temperature from -10°C to -35°C corresponding to a reduced pressure between0.35 and .16. The conclusion from the measurements is that oil gives a reduction in heat transfer coefficient compared to pure CO2. The reduction in heat transfer coefficient is greater at high...... described in the present report is measured heat transfer coefficient and pressure drop for flow boiling of oil free and oil contaminated CO2. Measurements have been done on tube with internal diameter of 10 mm and 4 mm- The mass flux has been varied from 90 kg/m2s to 750 kg/m2s, heat flux from 5 kW/m2...

Optimization of a cascade refrigeration system using refrigerant C_3H_8 in high temperature circuits (HTC) and a mixture of C_2H_6/CO_2 in low temperature circuits (LTC)

International Nuclear Information System (INIS)

Nasruddin; Sholahudin, S.; Giannetti, N.; Arnas

2016-01-01

Highlights: • Multi-objective optimization is conducted in the cascade refrigeration system. • Combination of operating temperature and refrigerant performance has been studied. • Characteristic of C_3H_8 and a mixture of C_2H_6/CO_2 have been investigated. • Determining of CO_2 fraction to optimize refrigeration system has been done. - Abstract: This paper discusses the multi-objectives optimization of a cascade refrigeration system using refrigerant C_3H_8 in high temperature circuits (HTC) and a mixture of C_2H_6/CO_2 in low temperature circuits (LTC). The evaporator temperature, condenser temperature, C_2H_6/CO_2 mixture condensation temperature, cascade temperature differences, and the CO_2 mass fraction are chosen as the decision variables. Whereas cooling capacity, cold space temperature, and ambient temperature are taken as the constraints. The purpose of this research is to design a cascade refrigeration system whose optimum performance are defined in terms of economics and thermodynamics. Accordingly, there are two objective functions that should be simultaneously optimized including the total annual cost which consists of the capital and operational cost and the total exergy destruction of the system. To this aim, the optimum operating temperature of the system and CO_2 fraction should be determined so that the system has minimum exergy destruction and annual cost. Results show that, the optimum value of the decision variables for this system can be determined by trade-off between annual cost and exergy destruction.

Yield and characteristics of shale oil from the retorting of oil shale and fine oil-shale ash mixtures

International Nuclear Information System (INIS)

Niu, Mengting; Wang, Sha; Han, Xiangxin; Jiang, Xiumin

2013-01-01

Highlights: • The whole formation process of shale oil might be divided into four stages. • Higher ash/shale mass ratio intensified the cracking and coking of shale oil. • Ash/shale ratio of 1:2 was recommended for oil shale fluidized bed retort with fine oil-shale ash as solid heat carrier. - Abstract: For exploring and optimizing the oil shale fluidized bed retort with fine oil-shale ash as a solid heat carrier, retorting experiments of oil shale and fine oil-shale ash mixtures were conducted in a lab-scale retorting reactor to investigate the effects of fine oil-shale ash on shale oil. Oil shale samples were obtained from Dachengzi Mine, China, and mixed with fine oil-shale ash in the ash/shale mass ratios of 0:1, 1:4, 1:2, 1:1, 2:1 and 4:1. The experimental retorting temperature was enhanced from room temperature to 520 °C and the average heating rate was 12 °C min −1 . It was found that, with the increase of the oil-shale ash fraction, the shale oil yield first increased and then decreased obviously, whereas the gas yield appeared conversely. Shale oil was analyzed for the elemental analysis, presenting its atomic H/C ratio of 1.78–1.87. Further, extraction and simulated distillation of shale oil were also conducted to explore the quality of shale oil. As a result, the ash/shale mixing mass ratio of 1:2 was recommended only for the consideration of increasing the yield and quality of shale oil

Low Global Warming Potential Refrigerants for Commercial Refrigeration Systems

Energy Technology Data Exchange (ETDEWEB)

Fricke, Brian A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Vishaldeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-06-01

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the high refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Environmental concerns are driving regulations for the heating, ventilating, air-conditioning and refrigeration (HVAC&R) industry towards lower GWP alternatives to HFC refrigerants. Existing lower GWP refrigerant alternatives include hydrocarbons, such as propane (R-290) and isobutane (R-600a), as well as carbon dioxide (R-744), ammonia (R-717), and R-32. In addition, new lower GWP refrigerant alternatives are currently being developed by refrigerant manufacturers, including hydrofluoro-olefin (HFO) and unsaturated hydrochlorofluorocarbon (HCFO) refrigerants. The selection of an appropriate refrigerant for a given refrigeration application should be based on several factors, including the GWP of the refrigerant, the energy consumption of the refrigeration system over its operating lifetime, and leakage of refrigerant over the system lifetime. For example, focusing on energy efficiency alone may overlook the significant environmental impact of refrigerant leakage; while focusing on GWP alone might result in lower efficiency systems that result in higher indirect impact over the equipment lifetime. Thus, the objective of this Collaborative Research and Development Agreement (CRADA) between

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

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1993-11-28

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

Clathrate hydrate dissociation conditions of refrigerants R404A, R406A, R408A and R427A: Experimental measurements and thermodynamic modeling

International Nuclear Information System (INIS)

Hashemi, Hamed; Babaee, Saeedeh; Mohammadi, Amir H.; Naidoo, Paramespri; Ramjugernath, Deresh

2015-01-01

Highlights: • The application of refrigerant hydrates in cold storage systems is investigated. • Hydrate dissociation conditions of various refrigerants have been measured. • A correlative thermodynamic model was applied to the data. • Enthalpy of dissociation for the refrigerants studied calculated. • Experimental measurements performed over a wide range of pressures. - Abstract: Clathrate hydrate dissociation conditions were measured for four “alternative” refrigerants, viz. R404A, R406A, R408A and R427A. The experimental measurements were performed within the pressure range of (0.079 to 9.995) MPa and temperatures ranging from (272.7 to 288.7) K. An isochoric pressure-search method was used to perform the measurements. A thermodynamic model based on the van der Waals–Platteeuw (vdW–P) model was applied for the prediction of the dissociation conditions which were compared to the experimental measurements. The fluid phase was modeled using the MHV2 G E -EoS mixing rule along with the UNIFAC (original) activity model. The van der Waals–Platteeuw (vdW–P) model was used for the modeling of the hydrate phase. There was reasonable agreement between the experimental and predicted values

ANALISIS PERBANDINGAN EVAPORATOR KULKAS (LEMARI ES DENGAN MENGUNAKAN REFRIGERANT R-22 DAN R-134A

Directory of Open Access Journals (Sweden)

Imam Faozan

2017-03-01

Full Text Available Tulisan ini bertujuan untuk mengetahui komponen mesin refrigerasi khususnya pembahasan evaporator. Dalam penelitian ini digunakan lemari pendingin (kulkas sederhana untuk pengawetan dan pendinginan bahan makanan dalam rumah tangga. Untuk refrigerant yang digunakan adalah Refrigerant Freon  R – 22 dan  Freon R - 134a sebagai perbandingan dan untuk mengetahui performance evaporator ( COP pada mesin refrigerasi untuk rumah tangga. Lemari pendingin yang dianalisa berukuran tinggi  = 1 m, panjang  = 0,55 m  dan lebar 0,5 m. Temperatur evaporasi = -5°C dan temperature kondensasi = 40°C.

INTENSIFICATION OF MICROBIAL EXOPOLYSACCHARIDE ETHAPOLAN BIOSYNTHESIS ON MIXTURE OF MOLASSES AND SUNFLOWER OIL

Directory of Open Access Journals (Sweden)

T. P. Pirog

2017-12-01

Full Text Available The purpose of the research was to establish Acinetobacter sp. IMB B-7005 cultivation conditions, which provide the maximal synthesis of microbial exopolysaccharide ethapolan on a mixture of molasses and sunflower oil, and to explore the possibility of replacing refined oil in a mixture with molasses for waste one. On the basis of theoretical calculations of energy consumption for the synthesis of ethapolan and biomass, it was determined that the optimal molar ratio of the concentrations of energy-deficient (sucrose and energy-excessive (sunflower oil substrates in the mixture was 1.0:0.9. Experiments have shown that the highest values of exopolysaccharide synthesis were observed at a molar ratio of monosubstrates in mixture 1.0:1.1, which is as close as possible to the theoretically calculated one. It was shown that increasing concentration of molasses and refined oil in mixture from 1.0 to 1.5% was accompanied by increase in amount of synthesized exopolysaccharide and its synthesizing capacity by 1.2 and 1.3 times, respectively. The possibility of replacing refined oil in a mixture with molasses for various types of waste (after frying potatoes, meat, vegetables and mixed was established. The maximum parameters of exopolysaccharide synthesis (concentration 14 g/l, synthesizing capacity 3.5 g exopolysaccharide/g biomass were observed when using mixed waste oil for both inoculum obtaining and EPS biosynthesis. The obtained results testify to the possibility of development of universal technology for obtaining microbal exopolysaccharide ethapolan on a mixture of waste (molasses and waste oil independent of the type and provider of waste oil.

In-tube flow boiling of R-407C and R-407C/oil mixtures. Part 1: Microfin tube

Energy Technology Data Exchange (ETDEWEB)

Zuercher, O; Thome, J R; Favrat, D

1999-07-01

In-tube evaporation tests for R-407C and R-407C/oil are reported for a microfin tube. The tests were run at a nominal inlet pressure of 645 kPa (93.5 psia) at mass velocities of 100, 200 and 300 kg/(m{sup 2}{center{underscore}dot}s) (20.5, 41, and 61 lb/s{center{underscore}dot}ft{sup 2}) over nearly the entire vapor quality range. At similar operating conditions, pure R-407C performed similarly to previous pure R-134a tests at the highest mass velocity, but lower than R-134a for the other mass velocities. Any amount of oil tended to decrease local R-407C microfin heat transfer coefficients, especially at high vapor qualities were degradations of as much as 50% or more occurred. Two-phase pressure drops were increased by the presence of oil, especially at high vapor qualities. Buildup of the local oil mass fraction in the microfin test sections was observed at high vapor qualities, together with the formation of slowly flowing viscous liquid films, a phenomenon that became more acute at lower mass velocities.

Estimation of Freezing Point of Hydrocarbon and Hydrofluorocarbon Mixtures for Mixed Refrigerant jt Cryocooler

Science.gov (United States)

Hwang, G.; Lee, J.; Jeong, S.

2010-04-01

Estimating the freezing point of refrigerant is an essential part in designing an MR JT (Mixed refrigerant Joule-Thomson) cryocooler to prevent itself from clogging and to operate with stability. There were researches on estimating freezing point, but some of them resulted in the wrong prediction of clogging. In this paper, the freezing point of the MR is precisely estimated with caution of clogging. The solubility of HC (hydrocarbon) and HFC (hydrofluorocarbon) mixture components are obtained with their activity coefficients, which represent the molecular interaction among the components. The freezing points of the MR JT cryocooler are systematically investigated in the operating temperature range from 70 K to 90 K.

Impact of Refrigerated Storage on Quality of Oil from Freshwater Jarko (Wallago attu Fish.

Directory of Open Access Journals (Sweden)

Nusrat N. Memon

2010-12-01

Full Text Available The effect of refrigerated storage on the quality of freshwater fish oil Jarko (Wallago attu was evaluated by measuring fatty acid profile, free fatty acids (FFA, peroxide value (PV, acid value (AV, sponification value (SV, iodine value (IV and poylene index (PI up to the time period of 120 days. After 120 days storage, mono unsaturated fatty acids (MUFA and polyunsaturated fatty acids (PUFA contents were decreased by 24.89% and 33.70%, respectively. While, saturated fatty acids (SFA content was found to be increased by 26.82%, against the actual value. The change in polyunsaturated fatty acids during refrigerated storage was measured by the PI value. The PI decreased during storage due to lipid oxidation, but remained nearly constant after 90th day of storage. The results of PV, AV and FFA demonstrates that Wallago attu fish oil remained acceptable for consumption for 60 days but eventually exceeded the recommended values after 60 days of refrigerated storage.

Experimental investigation of hydrocarbon mixtures to replace HFC-134a in an automotive air conditioning system

International Nuclear Information System (INIS)

Wongwises, Somchai; Kamboon, Amnouy; Orachon, Banchob

2006-01-01

This paper presents an experimental study on the application of hydrocarbon mixtures to replace HFC-134a in automotive air conditioners. The hydrocarbons investigated are propane (R290), butane (R600) and isobutane (R600a). The measured data are obtained from an automotive air conditioning test facility utilizing HFC-134a as the refrigerant. The air conditioner, with a capacity of 3.5 kW driven by a Diesel engine, is charged and tested with four different ratios of hydrocarbon mixtures. The experiments are conducted at the same surrounding conditions. The temperature and pressure of the refrigerant at every major position in the refrigerant loop, the temperature, flow rate and humidity of air, torque and engine speed are recorded and analyzed. The parameters investigated are the refrigeration capacity, the compressor power and the coefficient of performance (COP). The results show that propane/butane/isobutane: 50%/40%/10% is the most appropriate alternative refrigerant to replace HFC-134a, having the best performance of all the hydrocarbon mixtures investigated

Impact of the lubricating oil on thermodynamic performances of reversible heat pumps; Impact de l'huile de lubrification sur les performances thermodynamiques des pompes a chaleur reversibles

Energy Technology Data Exchange (ETDEWEB)

Youbi-Idrissi, M

2003-12-01

This work deals with the effect of oil on the energy performances of refrigerating systems. To characterise this impact, two thermodynamic properties were studied: the solubility and the enthalpy. Thus, a simple measurement method was presented, allowing to study both transient and steady-state behaviour of various refrigerant/oil pairs. Thus, experimental data were validated and modelled. The suitable use of the solubility curves showed the zeotropic character of the refrigerant/oil mixture, which is directly reflected on the enthalpy calculation. For this property, a thermodynamic model was developed and experimentally validated. Its application led to a new presentation of the Mollier diagram taking into account the oil presence. It was then shown that, among all the circuit elements, the evaporator is the most penalized by the oil presence. Its performances decrease when the circulating mass fraction of oil increases, the superheat decreases and when the refrigerant-oil solubility increases. An experimental study on a reversible heat pump confirmed that if the circulation mass fraction of oil in the machine is lower than 2%, the impact of oil is reduced. Lastly, a local model of a refrigerating unit, initially charged with a zeotropic mixture, allowed to analyse the profiles of temperature, heat transfer coefficient and local composition of the refrigerant along a circuit. (author)

Condensation of pure and near-azeotropic refrigerants in microfin tubes: A new computational procedure

Energy Technology Data Exchange (ETDEWEB)

Cavallini, A; Del Col, D; Mancin, S; Rossetto, L [Dipartimento di Fisica Tecnica, University of Padova, Via Venezia 1, Padova 35131 (Italy)

2009-01-15

Microfin tubes are widely used in air cooled and water cooled heat exchangers for heat pump and refrigeration applications during condensation or evaporation of refrigerants. In order to design heat exchangers and to optimize heat transfer surfaces, accurate procedures for computing pressure drops and heat transfer coefficients are necessary. This paper presents a new simple model for the prediction of the heat transfer coefficient to be applied to condensation in horizontal microfin tubes of halogenated and natural refrigerants, pure fluids or nearly azeotropic mixtures. The updated model accounts for refrigerant physical properties, two-phase flow patterns in microfin tubes and geometrical characteristics of the tubes. It is validated against a data bank of 3115 experimental heat transfer coefficients measured in different independent laboratories all over the world including diverse inside tube geometries and different condensing refrigerants among which R22, R134a, R123, R410A and CO{sub 2}. (author)

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

Science.gov (United States)

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

2012-12-04

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

Impact of the lubricating oil on thermodynamic performances of reversible heat pumps; Impact de l'huile de lubrification sur les performances thermodynamiques des pompes a chaleur reversibles

Energy Technology Data Exchange (ETDEWEB)

Youbi-Idrissi, M.

2003-12-01

This work deals with the effect of oil on the energy performances of refrigerating systems. To characterise this impact, two thermodynamic properties were studied: the solubility and the enthalpy. Thus, a simple measurement method was presented, allowing to study both transient and steady-state behaviour of various refrigerant/oil pairs. Thus, experimental data were validated and modelled. The suitable use of the solubility curves showed the zeotropic character of the refrigerant/oil mixture, which is directly reflected on the enthalpy calculation. For this property, a thermodynamic model was developed and experimentally validated. Its application led to a new presentation of the Mollier diagram taking into account the oil presence. It was then shown that, among all the circuit elements, the evaporator is the most penalized by the oil presence. Its performances decrease when the circulating mass fraction of oil increases, the superheat decreases and when the refrigerant-oil solubility increases. An experimental study on a reversible heat pump confirmed that if the circulation mass fraction of oil in the machine is lower than 2%, the impact of oil is reduced. Lastly, a local model of a refrigerating unit, initially charged with a zeotropic mixture, allowed to analyse the profiles of temperature, heat transfer coefficient and local composition of the refrigerant along a circuit. (author)

Combustion of soybean oil and diesel mixtures for heating purposes

Energy Technology Data Exchange (ETDEWEB)

Guimaraes, Adriana Correa; Sanz, Jose Francisco [European University Miguel de Cervantes, Valladolid (Spain)], E-mail: acorrea@uemc.es; Hernandez, Salvador; Navas, Luis Manuel; Rodriguez, Elena; Ruiz, Gonzalo [University of Valladolid (Spain). Dept. of Agricultural and Forest Engineering; San Jose, Julio [University of Valladolid (Spain). Dept. of Energetic Engineering; Gomez, Jaime [University of Valladolid (Spain). Dept. of Communications and Signal Theory and Telematics Engineering

2008-07-01

Using blends of vegetable oils with petroleum derivates for heating purposes has several advantages over other energy application for vegetable oils. This paper presents the results of an investigation by use of soybean oil and diesel mixture as fuel for producing heat in conventional diesel installation. The paper is set out as follows: properties characterization of soybean oil as fuel and of diesel oil, as well as the mixture of both; selection of the mixture according to their physical chemical properties and how they adapt to conventional combustion installation; experimentation with the selected mixture, allowing the main combustion parameters to be measured; processing the collected data, values of combustion, efficiency and reduction of emissions. Conclusions show that the use of soybean oil and diesel mixture for producing heat energy in conventional equipment is feasible and beneficial for reduction emissions. (author)

R13B1 and R114 exergy-enthalpy charts and their usefulness in a refrigerating-heating process analysis

International Nuclear Information System (INIS)

de Rossi, F.; Mastrullo, R.; Sasso, M.; Sibilio, S.

1989-01-01

R13B1 and R114 exergy-enthalpy diagrams in SI units based on data and equations published by the International Institute of Refrigeration are presented. The charts cover the ranges of 0.5 kPa to 15000 kPa and 120 degrees C to 180 degrees C for R13B1 and 0.8 kPa to 5000 kPa and -70 degrees C to 250 degrees C for R114. In this paper an analysis of a cascade refrigerating-heating compound system is included to illustrate the use of the charts

Toxicity Data to Determine Refrigerant Concentration Limits

Energy Technology Data Exchange (ETDEWEB)

Calm, James M.

2000-09-30

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

Measurements of saturation densities in critical region and critical loci for binary R-32/125 and R-125/143a systems

Energy Technology Data Exchange (ETDEWEB)

Kishizawa, G.; Sato, H.; Watanabe, K.

1999-05-01

R-32/125 (difluoromethane/pentafluoroethane) and R-125/143a (pentafluoroethane/1,1,1-trifluoroethane) binary systems are promising alternative refrigerants to replace conventional refrigerants, i.e., R-22 and R-502. The saturated vapor- and liquid-density data in the critical region of these mixtures were measured using the visual observation of the miniscus disappearance in an optical cell. For the R-32/125 system, 35 saturation density data were measured at three compositions, 10, 35, and 50 mass % R-32. Nineteen saturation density data were also measured for R-125/143a (50/50 mass %). The critical temperatures and densities for these binary refrigerants were determined by taking into consideration the level and location of the meniscus disappearance as well as the intensity of the critical opalescence. Correlations to represent the critical loci of these binary refrigerants for an entire range of compositions have been developed. The experimental uncertainties of the saturation density data are estimated to be within 9 mK in temperature and 0.5 to 5.0 kg{center{underscore}dot}m{sup {minus}3} in density. The uncertainties of the critical temperature and density are estimated to be within 12 to 14 mK and 4 to 8 kg{center{underscore}dot}m{sup {minus}3}, respectively.

Depicting mass flow rate of R134a /LPG refrigerant through straight and helical coiled adiabatic capillary tubes of vapor compression refrigeration system using artificial neural network approach

Science.gov (United States)

Gill, Jatinder; Singh, Jagdev

2018-07-01

In this work, an experimental investigation is carried out with R134a and LPG refrigerant mixture for depicting mass flow rate through straight and helical coil adiabatic capillary tubes in a vapor compression refrigeration system. Various experiments were conducted under steady-state conditions, by changing capillary tube length, inner diameter, coil diameter and degree of subcooling. The results showed that mass flow rate through helical coil capillary tube was found lower than straight capillary tube by about 5-16%. Dimensionless correlation and Artificial Neural Network (ANN) models were developed to predict mass flow rate. It was found that dimensionless correlation and ANN model predictions agreed well with experimental results and brought out an absolute fraction of variance of 0.961 and 0.988, root mean square error of 0.489 and 0.275 and mean absolute percentage error of 4.75% and 2.31% respectively. The results suggested that ANN model shows better statistical prediction than dimensionless correlation model.

Auto-refrigerating cascade for superconducting applications

International Nuclear Information System (INIS)

Forrest, S.M.; Hall, P.H.; Missimer, D.J.

1987-01-01

Extremely low temperatures, in the range of 230 to 90 K, are achieved in a single circuit compression refrigeration system operated by a conventional compressor. The system relies upon a series of intermediate cooling stages. The refrigerant is a mixture and the system employs fractional condensation, distillation, phase separation and intermediate heat transfer. Each stage includes the steps of withdrawing a portion of the liquid condensate from the compressed vapor-liquid refrigerant mixture which enters the stage. The withdrawn condensate is then throttled to a lower pressure and is mixed with the refrigerant being recycled to the compressor from the final evaporator. Evaporating the throttled condensate absorbs heat from and at least partially condenses the compressed uncondensed vapor in the compressed mixture

Process of decomposing an oil mixture

Energy Technology Data Exchange (ETDEWEB)

Kubierschky, K

1917-12-02

A process is described for the decomposition of oil mixtures, and the like, by means of alcohol, characterized in that the subject mixture is brought into solution in high-grade alcohol, and this solution is washed countercurrent with dilute alcohol.

Thermodynamic comparision of R744/R600a and R744/R600 used in mid-high temperature heat pump system

Directory of Open Access Journals (Sweden)

Fan Xiao-Wei

2014-01-01

Full Text Available The mid-high temperature heat pump provides hot water at a relatively high temperature using some industrial waste heat as its source. Now, the main refrigerants in this application are CFC114, HCFC123, and HCFC142b, etc., which are scheduled to be phased out due to their high ozone depletion potential and global warmth potential. Some studies have been conducted to find an eco-friendly alternative. In this paper, the natural non-azeotropic mixtures R744/R600a and R744/R600 are analyzed as alternatives. The performance of the heat pump system using new mixture is discussed and compared with those with CFC114, HCFC123, and HCFC142b. Under the given operating conditions, the maximum heating COP should occur at the mass fractions of 18/82 for R744/R600a and 10/90 for R744/R600. Both of their COP are higher than those with the refrigerants of CFC114, HCFC123, and HCFC142b. The COP and volumetric heating capacity of the system with R744/R600a are superior to those with R744/R600.

Spectroscopic and Chemometric Analysis of Binary and Ternary Edible Oil Mixtures: Qualitative and Quantitative Study.

Science.gov (United States)

Jović, Ozren; Smolić, Tomislav; Primožič, Ines; Hrenar, Tomica

2016-04-19

The aim of this study was to investigate the feasibility of FTIR-ATR spectroscopy coupled with the multivariate numerical methodology for qualitative and quantitative analysis of binary and ternary edible oil mixtures. Four pure oils (extra virgin olive oil, high oleic sunflower oil, rapeseed oil, and sunflower oil), as well as their 54 binary and 108 ternary mixtures, were analyzed using FTIR-ATR spectroscopy in combination with principal component and discriminant analysis, partial least-squares, and principal component regression. It was found that the composition of all 166 samples can be excellently represented using only the first three principal components describing 98.29% of total variance in the selected spectral range (3035-2989, 1170-1140, 1120-1100, 1093-1047, and 930-890 cm(-1)). Factor scores in 3D space spanned by these three principal components form a tetrahedral-like arrangement: pure oils being at the vertices, binary mixtures at the edges, and ternary mixtures on the faces of a tetrahedron. To confirm the validity of results, we applied several cross-validation methods. Quantitative analysis was performed by minimization of root-mean-square error of cross-validation values regarding the spectral range, derivative order, and choice of method (partial least-squares or principal component regression), which resulted in excellent predictions for test sets (R(2) > 0.99 in all cases). Additionally, experimentally more demanding gas chromatography analysis of fatty acid content was carried out for all specimens, confirming the results obtained by FTIR-ATR coupled with principal component analysis. However, FTIR-ATR provided a considerably better model for prediction of mixture composition than gas chromatography, especially for high oleic sunflower oil.

Study of thermodynamic properties of HFC refrigerant mixtures for Loretz-cycled niew generation air-conditioning equipment; Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsu rikigaku seishitsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Watanabe, K; Sato, H [Keio University, Tokyo (Japan). Faculty of Science and Technology

1997-02-01

This paper describes thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipment. Equipment has been completed for simultaneous measurement of density and vapor-liquid equilibrium property, accurate measurement of latent heat of vaporization, and accurate measurement of specific heat at constant pressure in liquid phase. Final adjustment and preliminary measurements are currently conducted. Through analytical investigation using actually measured data of thermodynamic properties of HFC refrigerant mixtures, five state equations were obtained, i.e., modified Peng-Robinson state equation which can reproduce the vapor-liquid equilibrium property of refrigerant mixtures, modified Patel-Teja state equation, Helmholtz function type state equation which is applicable in the whole fluid region of refrigerant mixtures, and so on. An evaluation test equipment has been fabricated as a trial for Lorentz-cycled air-conditioning equipments using HFC refrigerant mixtures, and demonstration test is conducted to confirm the validity. 9 refs., 5 figs.

Study of change of refrigerant R22 in chiller units by simulation in EcosimPro

International Nuclear Information System (INIS)

Prieto, J.; Molina, C.; Olmedo, J.; Gavilan, C. J.

2014-01-01

On January 1, 2010 is forbidden to hold any stock of virgin R 2 2 refrigerant and it is also forbidden to use virgin R 2 2 refrigerant for the service and maintenance of equipment under the new European Community Regulation 20137/2000. On January 1, 2015 and stock of R 2 2, even if reclaimed or recycled, will be illegal to hold. In accordance with the European Community regulation, Cofrentes Nuclear Power Plant begins the R 2 2 retrofit. (Author)

Dimensioning of flanged heat exchangers using the CYRANO software: pure refrigerants and mixtures; Dimensionnement des batteries a ailettes a l`aide du logiciel CYRANO: frigorigenes purs et melanges

Energy Technology Data Exchange (ETDEWEB)

Bensafi, A; Borg, S [CETIAT, Centre Technique des Industries Aerauliques et Thermiques, 69 - Villeurbanne (France)

1998-12-31

A software for the dimensioning and simulation of flanged heat exchangers is presented. This software divides the exchanger into pipe sections in which local values of physical properties of fluids and thermal exchange coefficients are used, and for which individual thermal-hydraulic performances are determined. CYRANO can be used for condensers, evaporators and monophase exchanges, with refrigerants like water, R22, R134a and R32/R125/R134a mixtures. The software can be used also in the case of specified complex circuits, equipped with smooth or grooved pipes and with smooth continuous, corrugated or slatted flanges with non-homogeneous air temperature and velocity distributions. The validation of CYRANO was performed on 7 exchangers with and without humidity condensation on the flanges. Comparisons with test results show that the average of errors in exchanged powers is of about 5%, and of about 30% in the case of internal pressure drops. Some simulations of exchangers with HFC mixtures are also presented. (J.S.) 34 refs.

Dimensioning of flanged heat exchangers using the CYRANO software: pure refrigerants and mixtures; Dimensionnement des batteries a ailettes a l`aide du logiciel CYRANO: frigorigenes purs et melanges

Energy Technology Data Exchange (ETDEWEB)

Bensafi, A.; Borg, S. [CETIAT, Centre Technique des Industries Aerauliques et Thermiques, 69 - Villeurbanne (France)

1997-12-31

A software for the dimensioning and simulation of flanged heat exchangers is presented. This software divides the exchanger into pipe sections in which local values of physical properties of fluids and thermal exchange coefficients are used, and for which individual thermal-hydraulic performances are determined. CYRANO can be used for condensers, evaporators and monophase exchanges, with refrigerants like water, R22, R134a and R32/R125/R134a mixtures. The software can be used also in the case of specified complex circuits, equipped with smooth or grooved pipes and with smooth continuous, corrugated or slatted flanges with non-homogeneous air temperature and velocity distributions. The validation of CYRANO was performed on 7 exchangers with and without humidity condensation on the flanges. Comparisons with test results show that the average of errors in exchanged powers is of about 5%, and of about 30% in the case of internal pressure drops. Some simulations of exchangers with HFC mixtures are also presented. (J.S.) 34 refs.

Bioremediation potential of a tropical soil contaminated with a mixture of crude oil and production water.

Science.gov (United States)

Alvarez, Vanessa Marques; Santos, Silvia Cristina Cunha Dos Santos; Casella, Renata da Costa; Vital, Ronalt Leite; Sebastin, Gina Vasquez; Seldin, Lucy

2008-12-01

A typical tropical soil from the northeast of Brazil, where an important terrestrial oil field is located, was accidentally contaminated with a mixture of oil and saline production water. To study the bioremediation potential in this area, molecular methods based on PCR-DGGE were used to determine the diversity of the bacterial communities in bulk and in contaminated soils. Bacterial fingerprints revealed that the bacterial communities were affected by the presence of the mixture of oil and production water, and different profiles were observed when the contaminated soils were compared with the control. Halotolerant strains capable of degrading crude oil were also isolated from enrichment cultures obtained from the contaminated soil samples. Twenty-two strains showing these features were characterized genetically by amplified ribosomal DNA restriction analysis (ARDRA) and phenotypically by their colonial morphology and tolerance to high NaCl concentrations. Fifteen ARDRA groups were formed. Selected strains were analyzed by 16S rDNA sequencing, and Actinobacteria was identified as the main group found. Strains were also tested for their growth capability in the presence of different oil derivatives (hexane, dodecane, hexadecane, diesel, gasoline, toluene, naphthalene, o-xylene, and p-xylene) and different degradation profiles were observed. PCR products were obtained from 12 of the 15 ARDRA representatives when they were screened for the presence of the alkane hydroxylase gene (alkB). Members of the genera Rhodococcus and Gordonia were identified as predominant in the soil studied. These genera are usually implicated in oil degradation processes and, as such, the potential for bioremediation in this area can be considered as feasible.

Multi-ejector concept for R-744 supermarket refrigerators; Multi-Ejektoren Konzept fuer R-744 Supermarkt-Kaelteanlagen

Energy Technology Data Exchange (ETDEWEB)

Hafner, Armin [SINTEF Energy Research, Trondheim (Norway); Foersterling, Sven [TLK-Thermo GmbH, Braunschweig (Germany); Banasiak, Krzystof [Silesian Univ. of Technology, Gliwice (Poland)

2012-07-01

Supermarkets are commercial buildings with major energy consumption and contribute also to relatively large direct emissions of greenhouse (GHG) through emissions of refrigerants from the refrigeration plants and the air conditioning system installed. The huge majority of these systems, which are installed in European supermarkets, are applying HFC-404A as working fluid. Average annual leakage rates in Europe are in the range of 15-20 % of the total charge. Worldwide the figure is about 30 % and HCFC-22 being the main refrigerant in use. Restrictions on the use of synthetic refrigerants are coming into force in several countries. There is a need for a natural refrigerant which allows for a safe investment in efficient refrigeration systems which will not be forced to be retrofitted by legislation in the future. Systems applying R-744 as the only refrigerant have been developed and more than 500 supermarkets exist in Europe, mainly in northern and mid-European countries. However, the systems still have large potential in development with respect to energy efficiency, heat recovery and cost efficiency. The paper describes the calculation method to identify the possible annual energy savings for different supermarket systems layout. The adoption of non-controlled ejectors and additional function such as heat recovery are evaluated. Results show relevant improvements in system efficiency when heat recovery has been adopted. Ejector usage is not widely spread at the moment. Thus, a theoretical analysis applying the programming language Modelica has been carried out. (orig.)

Oil-free heat pump plants with R744 (CO{sub 2}); Oelfreie Waermepumpenanlagen mit R744 (CO{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Hafner, Armin [SINTEF Energy Research, Trondheim (Norway)

2011-07-01

Refrigeration systems must have a certain oil level to ensure lubrication of mechanical components of the compressor. Some of the oil will escape from the compressor into the working fluid and thus into the cooling circuit (heat exchanger, tubes, header, etc.) The advantages of oil-free R744 refrigerators are assessed for different applications, e.g. industrial cooling (e.g. in supermarket), cooling during transport, cooling on board ships for production of cooled sea water, and in industrial heat pumps. The simpler design of oil-free systems will result in lower construction cost and also in a lower life cycle cost. The CREATIV project focussed on the development of an oil-free, hermetically sealed compressor. The compressor will be installed in the SINTEF-/NTNU laboratories at Trondheim in 2012 and will then be tested on site in several pilot projects. [German] In Kaelteanlagen muss eine bestimmte Menge an Oel vorhanden sein, um die Schmierung von mechanisch bewegten Teilen des Verdichters sicherzustellen. Dieses Oel wird hauptsaechlich im Verdichter bevorratet, jedoch gelangt ein nicht unwesentlicher Anteil mit dem Arbeitsmedium in den Kaeltemittelkreislauf. Somit befindet sich eine nicht vernachlaessigbare Menge an Schmiermittel in den Waermeuebertragern, Rohrleitungen, im Sammler etc. Die Vorteile von oelfreien R744-Kaelteanlagen im Vergleich zu konventionellen Kaelteanlagen werden fuer unterschiedliche Anwendungen bewertet: grosstechnische Kuehlung (z. B. Supermarktkuehlung), Transportkuehlung, an Bord von Schiffen bei der Produktion von gekuehltem Meerwasser (RSW) und von industriellen Waermepumpen. Aufgrund der viel einfacheren Bauweise von oelfreien Anlagen werden die Anlagenkosten meistens reduziert. Durch Reduzierung von Service- und Instandhaltungsarbeiten sowie einer verbesserten Systemleistung, die zu einem energieeffizienteren Betrieb fuehrt, sind die Gesamtkosten waehrend der Lebensdauer (Life Cycle Costs) einer oelfreien Anlage im Vergleich zu

Taguchi Method for Development of Mass Flow Rate Correlation using Hydrocarbon Refrigerant Mixture in Capillary Tube

Directory of Open Access Journals (Sweden)

Shodiya Sulaimon

2014-07-01

Full Text Available The capillary tube is an important control device used in small vapor compression refrigeration systems such as window air-conditioners, household refrigerators and freezers. This paper develops a non-dimensional correlation based on the test results of the adiabatic capillary tube for the mass flow rate through the tube using a hydrocarbon refrigerant mixture of 89.3% propane and 10.7% butane (HCM. The Taguchi method, a statistical experimental design approach, was employed. This approach explores the economic benefit that lies in studies of this nature, where only a small number of experiments are required and yet valid results are obtained. Considering the effects of the capillary tube geometry and the inlet condition of the tube, dimensionless parameters were chosen. The new correlation was also based on the Buckingham Pi theorem. This correlation predicts 86.67% of the present experimental data within a relative deviation of -10% to +10%. The predictions by this correlation were also compared with results in published literature.

Use of ATR-FTIR spectroscopy coupled with chemometrics for the authentication of avocado oil in ternary mixtures with sunflower and soybean oils.

Science.gov (United States)

Jiménez-Sotelo, Paola; Hernández-Martínez, Maylet; Osorio-Revilla, Guillermo; Meza-Márquez, Ofelia Gabriela; García-Ochoa, Felipe; Gallardo-Velázquez, Tzayhrí

2016-07-01

Avocado oil is a high-value and nutraceutical oil whose authentication is very important since the addition of low-cost oils could lower its beneficial properties. Mid-FTIR spectroscopy combined with chemometrics was used to detect and quantify adulteration of avocado oil with sunflower and soybean oils in a ternary mixture. Thirty-seven laboratory-prepared adulterated samples and 20 pure avocado oil samples were evaluated. The adulterated oil amount ranged from 2% to 50% (w/w) in avocado oil. A soft independent modelling class analogy (SIMCA) model was developed to discriminate between pure and adulterated samples. The model showed recognition and rejection rate of 100% and proper classification in external validation. A partial least square (PLS) algorithm was used to estimate the percentage of adulteration. The PLS model showed values of R(2) > 0.9961, standard errors of calibration (SEC) in the range of 0.3963-0.7881, standard errors of prediction (SEP estimated) between 0.6483 and 0.9707, and good prediction performances in external validation. The results showed that mid-FTIR spectroscopy could be an accurate and reliable technique for qualitative and quantitative analysis of avocado oil in ternary mixtures.

Numerical investigation of boiling heat transfer on hydrocarbon mixture refrigerant in vertical rectangular minichannel

OpenAIRE

Huixing Li; Yu Liu

2016-01-01

In order to investigate the characteristics of boiling heat transfer for hydrocarbon mixture refrigerant in plate-fin heat exchanger which is used in the petrochemical industry field, a model was established on boiling heat transfer in vertical rectangular channel. The simulated results were compared with the experimental data from literature. The results show that the deviation between the simulated results and experimental data is within ±15%. Meanwhile, the characteristic of boiling heat t...

Experimental investigations on automobile air conditioners working with R134a and R290/R600a as an alternative

Directory of Open Access Journals (Sweden)

Kandhaswamy Karthikeyan

2017-01-01

Full Text Available In this work, the performance of R134a based automobile air conditioning system has been evaluated by retrofitted with R290/R600a mixture (in the ratio of 50:50, by mass, as an alternative. The performance was evaluated at five different operating speeds (1000, 1500, 2000, 2500, and 3000, which covers the entire range of working conditions with four different cabin load (100, 200, 300, and 400 W. The condenser inlet air temperature was varied in the range between 30 and 50°C, which covers the entire climatic variations in Coimbatore city of India. The performance characteristics such as, refrigerating effect, coefficient of performance, compressor power consumption, and compressor discharge temperatures were considered for comparison. The results showed that, hydrocarbon mixture has faster cooling rate due to its high latent heat of vaporization, 5% higher coefficient of performance due to higher refrigeration effect, 8-10 K lower compressor discharge temperature due to its lower specific heat ratio with 5% lower compressor power consumption due to its lower viscosity and lower liquid density. The charge requirement of R290/R600a mixture is about 50% less compared to R134a. However, the mixture composition is considered as an interment replacement in automobile air conditioners due to composition shift under leak-age conditions. Hence, R290/R600a mixture is considered as an interim energy efficient and environment friendly option in R134a automobile air conditioners to extend its life.

Thermodynamic analysis of hydrocarbon refrigerants in a sub-cooling refrigeration system

Directory of Open Access Journals (Sweden)

BUKOLA O. BOLAJI

2013-06-01

Full Text Available In this study, the performance simulation of some hydrocarbon refrigerants (R290, R600 and R600a as alternatives to R134a in refrigeration system with sub-cooling is conducted by thermodynamic calculation of performance parameters using the REFPROP software. The results obtained showed that the saturated vapour pressure and temperature characteristic profiles for R600 and R600a are very close to that of R134a. The three hydrocarbon refrigerants exhibited very high refrigerating effect and condenser duty than R134a. The best of these parameters was obtained using R600. The discharge temperatures obtained using R600 and R600a were low, while that of R290 was very much higher. The highest coefficient of performance (COP and relative capacity index were obtained using R600. Average COPs of R600 and R600a are 4.6 and 2.2% higher than that of R134a, respectively. The performances of R600 and R600a in system were better than those of R134a and R290. The best performance was obtained using R600 in the system.

Desolventizing of soybean oil/azeotrope mixtures using ceramic membranes.

Science.gov (United States)

de Melo, Jonas R M; Tiggeman, Lidia; Rezzadori, Katia; Steffens, Juliana; Palliga, Marshall; Oliveira, J Vladimir; Di Luccio, Marco; Tres, Marcus V

2017-08-01

This work investigates the use of ceramic membranes with different molecular weight cut-offs (MWCOs: 5, 10 and 20 kDa) to desolventize azeotropic solvent mixtures (ethanol/n-hexane and isopropyl alcohol/n-hexane) from soybean oil/azeotrope micelles. Results show that a decrease in the MWCO of a membrane and an increase in the solvent mass ratio in the mixture resulted in a significant reduction in the permeate flux. The 20 kDa membrane presented the highest permeate flux, 80 and 60 kg/m 2 h for the soybean oil/n-hexane/isopropyl alcohol and soybean oil/n-hexane/ethanol azeotropes, respectively, for an oil to solvent ratio of 1:3 (w/w). The highest oil retention was found using the n-hexane/isopropyl alcohol azeotrope, around 25% in the membrane with the lowest MWCO, that is, 5 kDa. It is shown that the azeotropic mixtures provided intermediate characteristics compared to the original pure solvent behavior.

Heating Performance Analysis of a Geothermal Heat Pump Working with Different Zeotropic and Azeotropic Mixtures

Directory of Open Access Journals (Sweden)

Robert Bedoić

2018-06-01

Full Text Available The aim of the paper is to examine the possibility of application of the spreadsheet calculator and Reference Fluid Thermodynamic and Transport Properties database to a thermodynamic process. The heating process of a real soil-to-water heat pump, including heat transfer in the borehole heat exchanger has been analysed. How the changes of condensing temperature, at constant evaporating temperature, influence the following: heating capacity, compressor effective power, heat supplied to evaporator, compression discharge temperature and coefficient of performance, are investigated. Also, the energy characteristics of a heat pump using different refrigerants for the same heating capacity and the same temperature regime are compared. The following refrigerants are considered: two zeotropic mixtures, R407C and R409A, a mixture with some zeotropic characteristics, R410A, and an azeotropic mixture, R507A.

Fuel properties of biodiesel from vegetable oils and oil mixtures. Influence of methyl esters distribution

International Nuclear Information System (INIS)

Martínez, G.; Sánchez, N.; Encinar, J.M.; González, J.F.

2014-01-01

In this work, the quality of biodiesel produced by basic transesterification from several vegetable oils (soybean, rapeseed, sunflower, high oleic sunflower, Cynara Cardunculus L., Brassica Carinata and Jatropha Curca) cultivated in Extremadura has been studied in detail. The influence of raw material composition on properties such as density, viscosity, cetane number, higher heating value, iodine and saponification values and cold filter plugging point has been verified. Other biodiesel properties such as acid value, water content and flash and combustion points were more dependent on characteristics of production process. Biodiesel produced by rapeseed, sunflower and high oleic sunflower oils transesterification have been biofuels with better properties according to Norm EN 14214. Finally, it has been tested that it is possible to use oils mixtures in biodiesel production in order to improve the biodiesel quality. In addition, with the same process conditions and knowing properties of biodiesel from pure oils; for biodiesel from oils mixtures, its methyl esters content, and therefore properties dependent this content can be predicted from a simple mathematical equation proposed in this work. - Highlights: • Biodiesel quality produced by basic transesterification from vegetable oils. • We examine influences of methyl esters distribution on biodiesel properties. • Biofuels from soybean, sunflower and rapeseed oils were with better properties. • Oils mixtures improve biodiesel quality to fulfill Norm EN 14214. • An equation to predict properties of biodiesel from oil mixtures is proposed

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1997-02-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using 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.

Classification of refrigerants; Classification des fluides frigorigenes

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This document was made from the US standard ANSI/ASHRAE 34 published in 2001 and entitled 'designation and safety classification of refrigerants'. This classification allows to clearly organize in an international way the overall refrigerants used in the world thanks to a codification of the refrigerants in correspondence with their chemical composition. This note explains this codification: prefix, suffixes (hydrocarbons and derived fluids, azeotropic and non-azeotropic mixtures, various organic compounds, non-organic compounds), safety classification (toxicity, flammability, case of mixtures). (J.S.)

Experimental comparison between R409A and R437A performance in a heat pump unit

Directory of Open Access Journals (Sweden)

Duarte M. V.

2017-04-01

Full Text Available This paper reports an experimental comparison between the use of the refrigerants R409A and R437A in a heat pump unit designed and developed to work with R12. Although the use of both refrigerants in new equipments were abolished in EU and US according the new F-Gas Regulation of EU and SNAP, they still being used as options for R12 in old equipments, especially in developing countries. Both refrigerants were studied for the same test conditions, according to two groups of tests: group A (variation of the heat source temperature and group B (variation of refrigerant flow rate. The results obtained showed that the R437A presents a higher discharge pressure and a lower discharge temperature. The heating and cooling capacities of both refrigerants were similar, as well as the exergetic efficiency. For the group A of tests the COP of both refrigerants was similar and for the group B of tests the R409A presented an average COP 15% higher. According to the results obtained it is recommended the use of R409A in old equipments (as transition refrigerant until the acquisition of equipments operating with refrigerants with low-GWP becomes technically and economic feasible.

System performance with R407A, R407B, R407C compared to R22

DEFF Research Database (Denmark)

Knudsen, Hans Jørgen Høgaard

1997-01-01

both the cooling capacity and COP are smaller then the cooling capacity and COP with R22. The cooling capacity for R407A and R407B is lower than the capacity for R22 for brine temperatures less than 0 C and higher then the cooling capacity for R22 for brine temperatures higher than 0 C. The COP for R......407A and R407B er lower than the COP for R22.The volumetric and isentropic efficiency of the compressor are with mixture higher than the volumetric and isentropic efficiency with R22.......The article presents the results obtained by substituting R22 with mixture of R32/R125/R134A (R407A, R407B and R407C) in an existing refrigeration plant. Cooling capacity, coefficient of performance and heat transfer coefficient in the evaporator have been measured.The results show that for R407C...

Experimental Assessment of residential split type air-conditioning systems using alternative refrigerants to R-22 at high ambient temperatures

International Nuclear Information System (INIS)

Joudi, Khalid A.; Al-Amir, Qusay R.

2014-01-01

Highlights: • R290, R407C and R410A in residential split A/C units at high ambient. • 1 and 2 TR residential air conditioners with R22 alternatives at high ambient. • Residential split unit performance at ambients up to 55 °C with R22 alternatives. - Abstract: Steady state performance of residential air conditioning systems using R22 and alternatives R290, R407C, R410A, at high ambient temperatures, have been investigated experimentally. System performance parameters such as optimum refrigerant charge, coefficient of performance, cooling capacity, power consumption, pressure ratio, power per ton of refrigeration and TEWI environmental factor have been determined. All refrigerants were tested in the cooling mode operation under high ambient air temperatures, up to 55 °C, to determine their suitability. Two split type air conditioner of 1 and 2 TR capacities were used. A psychrometric test facility was constructed consisting of a conditioned cool compartment and an environmental duct serving the condenser. Air inside the conditioned compartment was maintained at 25 °C dry bulb and 19 °C wet bulb for all tests. In the environmental duct, the ambient air temperature was varied from 35 °C to 55 °C in 5 °C increments. The study showed that R290 is the better candidate to replace R22 under high ambient air temperatures. It has lower TEWI values and a better coefficient of performance than the other refrigerants tested. It is suitable as a drop-in refrigerant. R407C has the closest performance to R22, followed by R410A

System performance with R407A, R407B, R407C compared to R22

DEFF Research Database (Denmark)

Knudsen, Hans Jørgen Høgaard

1997-01-01

been determined.The results show that for R407C both the cooling capacity and the COP are smaller than the cooling capacity and COP for R22. The cooling capacity for R407A and for R407B is lower then the cooling capacity for R22 for brine temperatures less than 0 C and higher than the capacity for R22...... for brine temperatures higher than 0 C. The COP for R407A and 407B are lower than the COP for R22.The volumetriv and isentropic efficiency of the compressor are with mixtures higher than the volumetric and isentropic efficiency with R22.......The paper presents the results obtained by substituting R22 with mixtures of R32/R124/134a (R407A, R407B and R407C) in an existing refrigeration plant. The cooling water flow and cooling water inlet temperature together with the brine flow and brine inlet temperature have been kept on a value...

Energy and environmental performance assessment of R744 booster supermarket refrigeration systems operating in warm climates

DEFF Research Database (Denmark)

Gullo, Paride; Elmegaard, Brian; Cortella, Giovanni

2016-01-01

This paper presents a theoretical comparison among different commercial refrigeration systems in terms of annual energy consumption and environmental impact. Eight configurations were studied: a R744/R134a cascade refrigeration system (baseline), a conventional and an improved R744 booster system...... as on the running modes of a conventional European supermarket. A transition zone, which occurred between sub critical and transcritical operations, was adopted.The results showed that all the enhanced configurations may achieve a comparable energy saving to the one of the baseline in both the selected locations...

Utilization of the heat of mixing in open-circuit throttle refrigerators

International Nuclear Information System (INIS)

Zhakharov, N.D.; Anikeev, G.N.; Grezin, A.K.

1986-01-01

Open-circuit throttle refrigerators based on gas mixtures operate, as a rule, according to a single-stream scheme. The refrigerating effect is determined by the isothermal throttling effect of the mixture in the cylinder under the conditions at the inlet to the cryogenic unit. The authors use the heat of mixing of the cryogenic mixtures to increase the available refrigerating effect. Data are presented on mixtures of nitrogen and Freon-13; the thermodynamic properties of these compounds have been investigated experimentally over a wide range of parameters. It was found that in the case of correct selection of the scheme and complex optimization of the parameters, two-stream throttle refrigerators exceed the single-stream throttle refrigerators by at least a factor of 1.5 with respect to relative useful energy. With account taken of the design, technological, and operational parameters, that which is most promising is the scheme with mixing of the components in reverse flow

HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

Energy Technology Data Exchange (ETDEWEB)

Fauvarque, P [ELF Atochem, Centre d` Application de Lavallois, 92 (France)

1998-12-31

This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

Energy Technology Data Exchange (ETDEWEB)

Fauvarque, P. [ELF Atochem, Centre d`Application de Lavallois, 92 (France)

1997-12-31

This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

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

1998-08-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist 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.

Effect of randomization of mixtures of butter oil and vegetable oil on absorption and lipid metabolism in rats

DEFF Research Database (Denmark)

Becker, C.; Lund, Pia; Hølmer, Gunhild Kofoed

2001-01-01

of the dietary fats compared. Data on the fate of such lipids beyond the bloodstream is rather scarce and animal model studies are needed. Aim of the study To compare the metabolism of butter oil and mixtures of butter and rapeseed oil, native or randomized, in a model. The regiospecific fatty acid distribution...... present in dietary fats was followed through absorption, chylomicron formation, and deposition in adipose tissue and in different liver lipids (triacylglycerols, phospholipids, and cholesterol esters). Methods Rats were fed for 6 weeks from weaning either butter oil (BO), a butteroil- rapeseed oil mixture...... (interesterification) of butter oil with rapeseed oil (65:35 w/w) for use as edible fat did not have any impact on the fatty acid composition beyond the chylomicron step when compared to the native mixture....

Energetic, economic and environmental impacts of using nanorefrigerant in domestic refrigerators in Malaysia

International Nuclear Information System (INIS)

Javadi, F.S.; Saidur, R.

2013-01-01

Highlights: • Energy saving of using nanorefrigerant except of normal refrigerant in domestic refrigerator is investigated in Malaysia. • Using nanorefrigerant cause to reduce energy consumption of domestic refrigerator. • The maximum energy saving would be happen in case of using 0.1% TiO 2 –mineral oil–R134a nanorefrigerant. • Emission reduction is an environmental effect of using nanorefrigerant. - Abstract: The electricity demand in the residential sector has increased rapidly in recent years in Malaysia. This is mainly due to lifestyle improvement; and is also associated with the increase in the number of domestic refrigerators in this tropical country. This paper investigates the effect of using nanorefrigerant on energy saving in domestic refrigerators and emission reduction of greenhouse gases as an environmental viewpoint. The combination of R-134a refrigerant with TiO 2 and Al 2 O 3 nanoparticles with different mass fractions was scrutinized as a new refrigerant. It has been found that the energy saving using nanorefrigerant (0.1% TiO 2 nanoparticle/Mineral Oil) would be greater than normal refrigerant, with 10,863 MW h reduction in energy consumption by the year 2030. In this regard, this technology will be environmentally friendly by decreasing greenhouse emission, especially in terms of carbon dioxide. Thus, nanorefrigerant can help to increase the performance of domestic refrigerators and reduce energy consumption. Favorable effect on emission reduction and economic justification were concluded

[Study of Determination of Oil Mixture Components Content Based on Quasi-Monte Carlo Method].

Science.gov (United States)

Wang, Yu-tian; Xu, Jing; Liu, Xiao-fei; Chen, Meng-han; Wang, Shi-tao

2015-05-01

Gasoline, kerosene, diesel is processed by crude oil with different distillation range. The boiling range of gasoline is 35 ~205 °C. The boiling range of kerosene is 140~250 °C. And the boiling range of diesel is 180~370 °C. At the same time, the carbon chain length of differentmineral oil is different. The carbon chain-length of gasoline is within the scope of C7 to C11. The carbon chain length of kerosene is within the scope of C12 to C15. And the carbon chain length of diesel is within the scope of C15 to C18. The recognition and quantitative measurement of three kinds of mineral oil is based on different fluorescence spectrum formed in their different carbon number distribution characteristics. Mineral oil pollution occurs frequently, so monitoring mineral oil content in the ocean is very important. A new method of components content determination of spectra overlapping mineral oil mixture is proposed, with calculation of characteristic peak power integrationof three-dimensional fluorescence spectrum by using Quasi-Monte Carlo Method, combined with optimal algorithm solving optimum number of characteristic peak and range of integral region, solving nonlinear equations by using BFGS(a rank to two update method named after its inventor surname first letter, Boyden, Fletcher, Goldfarb and Shanno) method. Peak power accumulation of determined points in selected area is sensitive to small changes of fluorescence spectral line, so the measurement of small changes of component content is sensitive. At the same time, compared with the single point measurement, measurement sensitivity is improved by the decrease influence of random error due to the selection of points. Three-dimensional fluorescence spectra and fluorescence contour spectra of single mineral oil and the mixture are measured by taking kerosene, diesel and gasoline as research objects, with a single mineral oil regarded whole, not considered each mineral oil components. Six characteristic peaks are

Modern reciprocating compressors for the use of high pressure refrigerants (e.g. R410A, CO2). Criteria for construction and lubricating systems; Moderne zuigercompressoren voor de toepassing van hogedrukkoudemiddelen (zoals R410A, CO2). Eisen aan constructie en smeersystemen

Energy Technology Data Exchange (ETDEWEB)

Van der Lande, C. [Uniechemie, Apeldoorn (Netherlands); Grosse-Kracht, R. [Bitzer, Kuehlmaschinenbau, Sindelfingen (Germany)

2005-09-01

The use of high pressure refrigerants like R410A (air conditioning and chillers) and CO2 (low temperature cascade in supermarkets) demands changes in the standard fine reciprocating compressors. The design accounts essential criteria like thermodynamic and physical properties and the interaction between refrigerants and applied lubricants. These are high pressures, the mass flow, the vapour density, the high specific cooling capacity, the power consumption and the temperatures of oil and discharge gasses. [Dutch] De toepassing van R410A (in de klimaat-techniek) en CO2 (in lagetemperatuurcascade-installaties voor de supermarkttoepassing) vereist een aanpassing van standaard semi-hermetische zuigercompressoren om de fysische- en thermodynamische eigenschappen van het koudemiddel tot hun recht te laten komen. Dit zijn vooral de optredende drukken, de massastroom, de dampdichtheid, de hoge specifieke koelcapaciteit, het opgenomen vermogen en de olie- en persgastemperatuur.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

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

1996-04-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on refrigerants. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates. Citations in this report are divided into the following topics: thermophysical properties; materials compatibility; lubricants and tribology; application data; safety; test and analysis methods; impacts; regulatory actions; substitute refrigerants; identification; absorption and adsorption; research programs; and miscellaneous documents. Information is also presented on ordering instructions for the computerized version.

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

Science.gov (United States)

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

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.

Migration of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling

Directory of Open Access Journals (Sweden)

Peng Hao

2011-01-01

Full Text Available Abstract The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt.%, the heat flux is from 10 to 100 kW·m-2, and the initial liquid-level height is from 1.3 to 3.4 cm. The experimental results indicate that the migration ratio of carbon nanotube increases with the increase of the outside diameter or the length of carbon nanotube. For the fixed type of carbon nanotube, the migration ratio decreases with the increase of the oil concentration or the heat flux, and increases with the increase of the initial liquid-level height. The migration ratio of carbon nanotube increases with the decrease of dynamic viscosity of refrigerant or the increase of liquid phase density of refrigerant. A model for predicting the migration ratio of carbon nanotubes in the refrigerant-based nanofluid pool boiling is proposed, and the predictions agree with 92% of the experimental data within a deviation of ±20%.

Characterisation of Oil-Gas Mixtures by Raman Spectroscopy

DEFF Research Database (Denmark)

Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

2004-01-01

. The present project deals with development of a technique for quick analysis of oil-gas mixtures. The main emphasis is laid on characterisation of gas phases in equilibrium with oil at high pressures and high temperatures by Raman spectroscopy. The Raman technique has a great potential of being useful, due...

A solar absorption refrigeration system operating with the mixture ammonia-lithium nitrate

Energy Technology Data Exchange (ETDEWEB)

Rivera, W.; Martinez, F.; Garcia-Valladares, O. [Centro de Investigacion en Energia de la Univ. Nacional Autonoma de Mexico, Mor (Mexico); Rivera, C.O. [Univ. Veracruzana, Campus Coatzacoalcos (Mexico)

2007-07-01

An intermittent solar absorption refrigeration system for ice production operating with the ammonia-lithium nitrate mixture has been developed in the Centro de Investigacion en Energia of the Universidad Nacional Autonoma de Mexico. The system consists basically of a compound parabolic concentrator (CPC), a generator-absorber, a condenser, a condensate tank, an expansion valve and an evaporator. The system was evaluated in sunny days with insolations above 20 MJ/m{sup 2}-day at different condenser temperatures. The generator temperatures varied from 108 to 121 C and the evaporator temperatures inside the camera from -8 to 0 C. The coefficients of performance (COP) varied from 0.13 to 0.26 depending of the operating temperatures of the system and the solar irradiation. (orig.)

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

Science.gov (United States)

Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

1987-01-01

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.

Condensation of nano-refrigerant inside a horizontal tube

Science.gov (United States)

Darzi, Milad; Sadoughi, M. K.; Sheikholeslami, M.

2018-05-01

In this paper, condensing pressure drop of refrigerant-based nanofluid inside a tube is studied. Isobutene was selected as the base fluid while CuO nanoparticles were utilized to prepare nano-refrigerant. However, for the feasibility of nanoparticle dispersion into the refrigerant, Polyester oil (POE) was utilized as lubricant oil and added to the pure refrigerant by 1% mass fraction. Various values of mass flux, vapor quality, concentration of nanoparticle are investigated. Results indicate that adding nanoparticles leads to enhance frictional pressure drop. Nanoparticles caused larger pressure drop penalty at relatively lower vapor qualities which may be attributed to the existing condensation flow pattern such that annular flow is less influenced by nanoparticles compared to intermittent flow regime.

Combined cold compressor/ejector helium refrigerator cycle

International Nuclear Information System (INIS)

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

1984-01-01

This chapter demonstrates how the use of a cold compressor in series with an ejector is an effective way to produce the desired low pressure in a helium refrigeration system. The cold compressor is tentatively located at the low pressure side below the J-T heat exchanger. The ejector is the first stage and the cold compressor is the second stage of the two-stage pumping system. A centrifugal, oil-bearing type compressor was installed on the R and D refrigerator at the Brookhaven National Laboratory. It is determined that the combined cold compressor and ejector system produces a lower temperature on the same load or more cooling at the same temperature compared with a system which uses an ejector alone. Results of the test showed a gain of 20%

Comparative Study of Breakdown Voltage of Mineral, Synthetic and Natural Oils and Based Mineral Oil Mixtures under AC and DC Voltages

Directory of Open Access Journals (Sweden)

Abderrahmane Beroual

2017-04-01

Full Text Available This paper deals with a comparative study of AC and DC breakdown voltages of based mineral oil mixtures with natural and synthetic esters mainly used in high voltage power transformers. The goal was to analyze the performances of oil mixtures from the dielectric withstand point of view and to predict the behavior of transformers originally filled with mineral oil and re-filled with synthetic or natural ester oils when emptied for maintenance. The study concerns mixtures based on 20%, 50%, and 80% of natural and synthetic ester oils. AC breakdown voltages were measured using a sphere-sphere electrode system according to IEC 60156 specifications; the same specification was adopted for DC measurements since there is no standard specifications for this voltage waveform. A statistical analysis of the mean values, standard deviations, and histograms of breakdown voltage data was carried out. The Normal and Weibull distribution functions were used to analyze the experimental data and the best function that the data followed was used to estimate the breakdown voltage with risk of 1%, 10%, and 50% probability. It was shown that whatever the applied voltage waveforms, ester oils always have a significantly higher breakdown voltage than mineral oil. The addition of only 20% of natural or synthetic ester oil was sufficient to considerably increase the breakdown voltage of mineral oil. The dielectric strength of such a mixture is much higher than that of mineral oil alone and can reach that of ester oils. From the point of view of dielectric strength, the mixtures constitute an option for improving the performance of mineral oil. Thus, re-filling of transformers containing up to 20% mineral oil residues with ester oils, does not present any problem; it is even advantageous when considering only the breakdown voltage. Under AC, the mixtures with natural ester always follow the behavior of vegetable oil alone. With the exception of the 20% mixture of natural

Performance of R290 and R1270 for R22 applications with evaporator and condenser temperature variation

International Nuclear Information System (INIS)

Park, Ki Jung; Jung, Dong Soo

2008-01-01

In this study, therma l performance of two hydrocarbon refrigerants of R290 and R1270 was measured in an attempt to substitute R22. They were tested in a heat pump bench tester of 1 ton capacity with a hermetic rotary compressor. Water and water/glycol mixture were employed as the secondary heat transfer fluids in the test bench. All tests were conducted under the same external conditions simulating three different air-conditioning and heat pumping conditions. Test results show that the coefficient of performance of these hydrocarbon refrigerants is up to 11.5% higher than that of R22 under all conditions. Refrigeration capacity of R290 is up to 8.2% lower than that of R22 under normal airconditioning and heat pumping conditions. Under extremely cold temperature conditions, however, the capacity of R290 is 5% higher than that of R22. On the other hand, the capacity of R1270 is similar to that of R22 under all conditions. Compressor discharge temperatures of these hydrocarbons are reduced by 14-31 .deg. C as compared to R22. The amount of charge is reduced up to 58% as compared to R22. Overall, these hydrocarbons provide good performance with reasonable energy savings without any environmental problems and thus can be used as long-term alternatives for residential air-conditioning and heat pumping applications

Transesterification of camelina sativa oil with supercritical alcohol mixtures

International Nuclear Information System (INIS)

Sun, Yingqiang; Ponnusamy, Sundaravadivelnathan; Muppaneni, Tapaswy; Reddy, Harvind K.; Wang, Jun; Zeng, Zheling; Deng, Shuguang

2015-01-01

Highlights: • Transesterification of camelina oil under supercritical methanol/ethanol and 1-butanol mixture conditions. • Chemical composition of fatty acid methyl esters, ethyl esters and butyl esters. • Effect of different alcohol molar ratio on biodiesel yields. • Effect of different alcohol molar ratio on physical properties of biodiesel products. - Abstract: The transesterification of camelina sativa oil with methanol–1-butanol, and ethanol–1-butanol alcohol mixtures under supercritical conditions have been studied in order to maximize biodiesel yield and improve biodiesel quality. The influence of the variation of the molar ratio of methanol–1-butanol and ethanol–1-butanol from 1:0, 3:1, 2:1, 1:1, 1:2, to 0:1 on the yield of free fatty methyl esters/free fatty ethanol esters–free fatty acid butyl esters, the composition of the biodiesel blend mixtures, and the physical properties of the biodiesel have been investigated at the reaction temperature of 290 °C, reaction time of 30 min, and the initial reaction pressure of 500 psi. A maximum yield of 86.14 wt% for free fatty acid methyl esters–free fatty acid butyl esters with the optimum cold property can be obtained at the molar ratio of methanol–1-butanol of 0.5–0.9. Also, a maximum yield of 85.60 wt% for free fatty ethyl esters–free fatty butyl esters with the lowest pour point can be achieved at the molar ratio of ethanol–1-butanol in the range of 0.5–0.7

Two-component mixture model: Application to palm oil and exchange rate

Science.gov (United States)

Phoong, Seuk-Yen; Ismail, Mohd Tahir; Hamzah, Firdaus Mohamad

2014-12-01

Palm oil is a seed crop which is widely adopt for food and non-food products such as cookie, vegetable oil, cosmetics, household products and others. Palm oil is majority growth in Malaysia and Indonesia. However, the demand for palm oil is getting growth and rapidly running out over the years. This phenomenal cause illegal logging of trees and destroy the natural habitat. Hence, the present paper investigates the relationship between exchange rate and palm oil price in Malaysia by using Maximum Likelihood Estimation via Newton-Raphson algorithm to fit a two components mixture model. Besides, this paper proposes a mixture of normal distribution to accommodate with asymmetry characteristics and platykurtic time series data.

Condensation of refrigerants in horizontal microfin tubes: comparison of prediction methods for heat transfer

Energy Technology Data Exchange (ETDEWEB)

Wang, H S; Honda, H [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

2003-06-01

A comparison was made between the predictions of previously proposed empirical correlations and theoretical model and available experimental data for the heat transfer coefficient during condensation of refrigerants in horizontal microfin tubes. The refrigerants tested were R11, R123, R134a, R22 and R410A. Experimental data for six tubes with the tube inside diameter at fin root of 6.49-8.8 8 mm, the fin height of 0.16-0.24 mm, fin pitch of 0.34-0.53 mm and helix angle of groove of 12-20{sup o} were adopted. The r.m.s. error of the predictions for all tubes and all refrigerants decreased in the order of the correlations proposed by Luu and Bergies [ASHRAE Trans. 86 (1980) 293], Cavallini et al. Condensation of new refrigerants inside smooth and enhanced tubes. In: Proc. 19th Int. Cong. Refrigeration, vol. IV, Hague, The Netherlands, 1995. p. 105-114, Shikazono et al. [Trans. Jap. Sco. Mech. Engrs. 64 (1995) 196], Kedzierski and Goncalves [J. Enhanced Heat Transfer 6 (1999) 16], Yu and Koyama [Yu J, Koyama S. Condensation heat transfer of pure refrigerants in microfin tubes. In: Proc. Int. Refrigeration Conference at Purdue Univ., West Lafayette, USA, 1998. p. 325-330], and the theoretical model proposed by Wang et al. [Int. J. Heat Mass Transfer 45 (2002) 1513]. (author)

An experimental and theoretical study on an injection-assisted air-conditioner using R32 in the refrigeration cycle

International Nuclear Information System (INIS)

Qv, Dehu; Dong, Bingbing; Cao, Lin; Ni, Long; Wang, Jijin; Shang, Runxin; Yao, Yang

2017-01-01

Highlights: • An advanced injection-assisted air-conditioner (IAC) using R32 was proposed. • In the whole day-night cycle, cooling capacity and energy efficiency ratio of the IAC were enhanced dramatically. • The injection duration of 8 s maximized the IAC cooling potential. • Two-phase injection attained the highest exergetic efficiency approximating 50% or more. • The economic and environmental benefits of the IAC were demonstrated. - Abstract: An air-conditioner (AC) that uses refrigerant R32 assisted with one-phase vapor injection shows high energy efficiency and low discharge temperature in the heat-pump cycle, but the performance is not satisfactory in the refrigeration cycle. In this study, an improved injection cycle consisting of one-phase vapor injection mode and two-phase injection mode is proposed and integrated into an AC using R32, which is now referred to as an advanced injection-assisted air-conditioner (IAC). Through an experimental and theoretical study, an optimal injection duration of 8 s is attained for maximizing the refrigeration potential of the IAC. Furthermore, in an entire day–night cycle, both the cooling capacity and energy efficiency ratio (EER) of the IAC within the two-phase injection cycle are enhanced by 25% and 32%, respectively, compared with those of a noninjection-assisted AC. Moreover, two-phase injection offers the highest exergetic efficiency, approximately 50% or more in the refrigeration cycle, exhibiting remarkable thermodynamic performance of the IAC. In addition, compared to the conventional AC using R410A, the IAC using R32 within a two-phase injection cycle demonstrates reasonable payback performance and substantial reduction in carbon dioxide and sulfur dioxide emissions in the refrigeration cycle.

Candidates to replace R-12 as a radiator gas in Cherenkov detectors

Science.gov (United States)

Harvey, Allan H.; Paulechka, Eugene; Egan, Patrick F.

2018-06-01

Dichlorodifluoromethane (R-12) has been widely used as a radiator gas in pressure threshold Cherenkov detectors for high-energy particle physics. However, that compound is becoming unavailable due to the Montreal Protocol. To find a replacement with suitably high refractive index, we use a combination of theory and experiment to examine the polarizability and refractivity of several non-ozone-depleting compounds. Our measurements show that the fourth-generation refrigerants R-1234yf (2,3,3,3-tetrafluoropropene) and R-1234ze(E) (trans-1,3,3,3-tetrafluoropropene) have sufficient refractivity to replace R-12 in this application. If the slight flammability of these compounds is a problem, two nonflammable alternatives are R-218 (octafluoropropane), which has a high Global Warming Potential, and R-13I1 (trifluoroiodomethane), which has low Ozone Depletion Potential and Global Warming Potential but may not be sufficiently inert.

Computer model of the refrigeration system of an ice rink

Energy Technology Data Exchange (ETDEWEB)

Teyssedou, G.; Zmeureanu, R. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Giguere, D. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Technology Centre

2008-07-01

This paper presented a refrigeration system model of an existing ice rink using a component approach. The chillers, the ice-concrete slab and the controller were the 3 main components used in the simulations which were performed using both open and closed loop systems. The simulated ice rink refrigeration system was based on measurements taken in an existing indoor ice rink located in Montreal, Quebec. Measurements of the refrigeration system included electricity demand; heat flux on the ice sheet; exterior air temperature; ice temperature; return brine temperature; brine temperature at the pump; brine temperature at both evaporator exits; and refrigerant temperature and pressure at the expansion and condenser valve exits. Simulation results and measurements were found to be in good agreement. A computer model of the refrigeration system was developed using the TRNSYS 16 program. The refrigeration system was composed of 2 chillers using refrigerant R-22. The impact of heat recovery from the condensers on the energy demand for sanitary water heating was also estimated. The potential reduction of equivalent carbon dioxide emissions was calculated using the total equivalent warming impact (TEWI) criterion in an effort to estimate the refrigeration impact on global warming. 12 refs., 4 tabs., 12 figs.

Effects of clove oil-phospholipid mixtures on rheology of gum tragacanth - possible application for surfactant action on mucus gel simulants.

Science.gov (United States)

Banerjee, R; Puniyani, R R

2000-01-01

The present study evaluates the effectiveness of specialised biomaterials consisting of clove oil- phospholipid mixtures as possible substitute surfactants in diseases of altered mucus viscosity by studying their effect on the viscosity of mucus gel simulants in vitro. Test surfactants consisting of phospholipid-clove oil mixtures in the ratio of 1 part of oil to 9 parts of phospholipid were prepared. The phospholipids used were dipalmitoyl phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) and binary mixtures of PC: PE and PC: PG in the ratio of 2 parts of PC to 3 parts of PE or PG. The effects of the phospholipid-clove oil mixtures on the viscosity of mucus gel simulant (MGS: a polymeric gel consisting predominantly of gum tragacanth and simulating respiratory mucus), was studied by application of steady shear rates ranging from 0.512 to 51.2/s in a concentric cylinder viscometer at 37 degrees C. The change in MGS viscosity, after incubation with surfactants, was found to have a non-Newtonian character and to follow the power law model with R2 values >0.8. The addition of clove oil-phospholipid mixtures caused a decrease in the MGS viscosity when compared with the effect of the phospholipid alone at low shear rates in case of PC, PG and PCPG. The combination of PC : PG with clove oil caused ratios of change in MGS viscosity < 1 i.e., caused a decrease in the MGS viscosity. PC: PG with clove oil was capable of lowering MGS viscosity and should be further researched as possible therapies for diseases of altered mucus rheology.

Experimental investigation of R-134a and R-600a refrigerant blend ...

African Journals Online (AJOL)

GWP) ≤ 150 according to the European Union protocol, alongside other properties, which no single refrigerant has met as at today. This study focused on blending of existing refrigerants towards obtaining blends with GWP ≤ 150.

Theoretical study on a novel dual-nozzle ejector enhanced refrigeration cycle for household refrigerator-freezers

International Nuclear Information System (INIS)

Zhou, Mengliu; Wang, Xiao; Yu, Jianlin

2013-01-01

Highlights: • A novel dual-nozzle ejector enhanced refrigeration cycle is proposed. • The novel cycle is evaluated by using the developed mathematical model. • The results show the performances of the novel cycle could be significantly improved. • The novel cycle shows its promise in household refrigerator-freezers applications. - Abstract: In this study, a novel dual-nozzle ejector enhanced refrigeration cycle is presented for dual evaporator household refrigerator-freezers. The proposed ejector equipped with two nozzles can efficiently recover the expansion work from cycle throttling processes and enhance cycle performances. The performances of the novel cycle are evaluated by using the developed mathematical model, and then compared with that of the conventional ejector enhanced refrigeration cycle and basic vapor-compression refrigeration cycle. The simulation results show that for the given operating conditions, the coefficient of performance (COP) of the novel cycle using refrigerant R134a is improved by 22.9–50.8% compared with that of the basic vapor-compression refrigeration cycle, and the COP improvement is 10.5–30.8% larger than that of the conventional ejector enhanced refrigeration cycle. The further simulation results of the novel cycle using refrigerant R600a indicate that the cycle COP and volumetric refrigeration capacity could be significantly improved

Performance analysis of the electric vehicle air conditioner by replacing hydrocarbon refrigerant

Science.gov (United States)

Santoso, Budi; Tjahjana, D. D. D. P.

2017-01-01

The thermal comfort in passenger cabins needs an automotive air-conditioning system. The electric vehicle air conditioner system is driven by an electric compressor which includes a compressor and an electric motor. Almost air-conditioning system uses CFC-12, CFC-22 and HFC-134a as refrigerant. However, CFC-12 and CFC-22 will damage the ozone layer. The extreme huge global warming potentials (GWP) values of CFC-12, CFC-22, and HFC-134a represent the serious greenhouse effect of Earth. This article shows new experimental measurements and analysis by using a mixture of HC-134 to replace HFC-134a. The result is a refrigerating effect, the coefficient of performance and energy factor increase along with cooling capacity, both for HFC-134a and HC-134. The refrigerating effect of HC-134 is almost twice higher than HFC-134a. The coefficient of performance value of HC-134 is also 36.42% greater than HFC-134a. Then, the energy factor value of HC-134 is 3.78% greater than HFC-134a.

Reassessment of forced convection heat transfer correlations for refrigerant-12

International Nuclear Information System (INIS)

Celata, G.P.; Cuomo, M.; D'Annibale, F.; Farello, G.E.; Setaro, T.

1986-01-01

In the frame of a Refrigerant-12 experiment on postulated accidental transients in Pressurized Water Reactors under way at Heat Transfer Laboratory (ENEA Casaccia Research Center), an assessment of the main correlation available in scientific literature, for the different heat transfer regions encountered when a liquid is boiled in a confined heated channel, has been performed. Considering a vertical tube uniformly heated over its length with CHF at the exit, the following heat transfer regimes may be individuated: convective heat transfer to liquid, subcooled boiling, saturated nucleate boiling, forced convective heat transfer through liquid film (annular flow regime) and thermal crisis. From the comparison of computed values with an original ENEA dataset, the best correlations in predicting Refrigerant-12 data have been individuated. In a few cases, though preserving the original structure of the correlations, mainly developed for water, it was necessary to adjust some coefficients by means of best-fit procedures through our experimental data. The work has been performed in the frame of the ENEA Thermal Reactor Department Safety Research Project

Simulation of absorption refrigeration system for automobile application

Directory of Open Access Journals (Sweden)

Ramanathan Anand

2008-01-01

Full Text Available An automotive air-conditioning system based on absorption refrigeration cycle has been simulated. This waste heat driven vapor absorption refrigeration system is one alternate to the currently used vapour compression refrigeration system for automotive air-conditioning. Performance analysis of vapor absorption refrigeration system has been done by developing a steady-state simulation model to find the limitation of the proposed system. The water-lithium bromide pair is used as a working mixture for its favorable thermodynamic and transport properties compared to the conventional refrigerants utilized in vapor compression refrigeration applications. The pump power required for the proposed vapor absorption refrigeration system was found lesser than the power required to operate the compressor used in the conventional vapor compression refrigeration system. A possible arrangement of the absorption system for automobile application is proposed.

The experimental investigation of refrigerant distribution and leaking characteristics of R290 in split type household air conditioner

International Nuclear Information System (INIS)

Tang, Weier; He, Guogeng; Cai, Dehua; Zhu, Yihao; Zhang, Aoni; Tian, Qiqi

2017-01-01

Highlights: • A new quasi-liquid nitrogen method (QLNM) was proposed and firstly applied in experiments. • The R290 distribution was investigated by QLNM and the results proved the validation. • A solenoid valve was proposed to install near the capillary in STHAC in order to reduce risk factor. • R290 leaking rate was firstly measured by QLNM before and after the installation a solenoid valve. - Abstract: As a high-profile replacement for R22 split type household air conditioner (STHAC), R290 has several advantages in terms of thermodynamic properties, environmental characteristics, and cost. However, the obvious shortcoming of R290 is its flammability, which has a potential fire risk to the building. At present, the most important measure to ensure the safety of a R290 STHAC is to limit the refrigerant charge by domestic and international standards. But in fact, when the leakage of R290 occur from a STHAC, the distribution of R290 in STHAC, and the leaking rate also will seriously affect the safety of an R290 STHAC. In this study, a new quasi-liquid nitrogen method (QLNM) has been proposed in order to investigate the refrigerant distribution in R290 STHACs and the leaking rate under various conditions, and the experiments have been conducted. The experimental results of distribution proved the validation of the QLNM and showed that a large portion of the refrigerant distributed in the condenser when the air conditioner is on running stage and the refrigerant will migrate from the condenser to the evaporator when the air conditioner is on closed stage. Based on this, the installation of a solenoid valve near the capillary has been proposed. The comparison of experimental results of R290 leaking rate before and after the installation of a solenoid valve showed it will obviously reduce the leaking rate and thereby improve the safety of the R290 STHACs.

Performance Analysis of Multipurpose Refrigeration System (MRS on Fishing Vessel

Directory of Open Access Journals (Sweden)

Ust Y.

2016-04-01

Full Text Available The use of efficient refrigerator/freezers helps considerably to reduce the amount of the emitted greenhouse gas. A two-circuit refrigerator-freezer cycle (RF reveals a higher energy saving potential than a conventional cycle with a single loop of serial evaporators, owing to pressure drop in each evaporator during refrigeration operation and low compression ratio. Therefore, several industrial applications and fish storage systems have been utilized by using multipurpose refrigeration cycle. That is why a theoretical performance analysis based on the exergetic performance coefficient, coefficient of performance (COP, exergy efficiency and exergy destruction ratio criteria, has been carried out for a multipurpose refrigeration system by using different refrigerants in serial and parallel operation conditions. The exergetic performance coefficient criterion is defined as the ratio of exergy output to the total exergy destruction rate (or loss rate of availability. According to the results of the study, the refrigerant R32 shows the best performance in terms of exergetic performance coefficient, COP, exergy efficiency, and exergy destruction ratio from among the other refrigerants (R1234yf, R1234ze, R404A, R407C, R410A, R143A and R502. The effects of the condenser, freezer-evaporator and refrigerator-evaporator temperatures on the exergetic performance coefficient, COP, exergy efficiency and exergy destruction ratios have been fully analyzed for the refrigerant R32.

Two-phase flow in refrigeration systems

CERN Document Server

Gu, Junjie; Gan, Zhongxue

2013-01-01

Two-Phase Flow in Refrigeration Systems presents recent developments from the authors' extensive research programs on two-phase flow in refrigeration systems. This book covers advanced mass and heat transfer and vapor compression refrigeration systems and shows how the performance of an automotive air-conditioning system is affected through results obtained experimentally and theoretically, specifically with consideration of two-phase flow and oil concentration. The book is ideal for university postgraduate students as a textbook, researchers and professors as an academic reference book, and b

Quality control of mixtures consisting of engine oil and rapeseed oil by means of online oil sensors; Qualitaetsueberwachung von Motoroel-Rapsoelmischungen mit Online-Oelsensoren. Labortests

Energy Technology Data Exchange (ETDEWEB)

Thuneke, Klaus; Schreiber, Katja [Technologie- und Foerderzentrum, Straubing (Germany)

2013-10-01

It was the goal of the work to investigate interactions between motor oils and rapeseed oil fuel and to test oil sensors for monitoring the quality of aged mixtures of motor oil and rapeseed oil. At first oil samples were aged in the laboratory, whereby motor oil type, share of rapeseed oil and aeration was varied. Depending on type of engine oil different ageing effects were noticed. Higher shares of rapeseed and aeration stimulate increase of viscosity and acid value. In a further step online oil sensors were tested in both, a model of a lubrication system and a test engine. The signals of the sensors plausibly described the oil ageing process by the indicators dynamic or acoustic viscosity, permittivity number, specific electric conductivity. In particular viscosity and permittivity are suitable for showing changes in different motor oil rapeseed oil mixtures during oil ageing. However, for a reliable control system detecting critical rapeseed oil enrichment in the motor oil onboard, further work has to be done. (orig.)

EXPERIMENTAL STUDY OF PALM OIL MILL EFFLUENT AND OIL PALM FROND WASTE MIXTURE AS AN ALTERNATIVE BIOMASS FUEL

Directory of Open Access Journals (Sweden)

S. HASSAN, L. S. KEE

2013-12-01

Full Text Available Palm oil mill effluent (POME sludge generated from palm oil mill industry and oil palm frond (OPF from oil palm plantation are considered biomass wastes that can be fully utilized as a renewable energy sources. In this study, an attempt has been made to convert these residues into solid biomass fuel. The study was conducted by developing experimental testing on the POME and OPF mixture. The performance of each sample with different weight percentage was investigated using standard tests. The biomass mixture was converted into compressed form of briquette through a simple process. The properties of the briquettes were observed and compared at different weight percentage following standard testing methods included ultimate and proximate analyses, burning characteristics, dimensional stability and crack analysis. Experimental results showed that POME sludge and OPF mixture is feasible as an alternative biomass fuel, with briquette of 90:10 POME sludge to OPF ratio has a good combination of properties as an overall.

Prediction of thermodynamic properties of refrigerants using data mining

International Nuclear Information System (INIS)

Kuecueksille, Ecir Ugur; Selbas, Resat; Sencan, Arzu

2011-01-01

The analysis of vapor compression refrigeration systems requires the availability of simple and efficient mathematical formulations for the determination of thermodynamic properties of refrigerants. The aim of this study is to determine thermodynamic properties as enthalpy, entropy and specific volume of alternative refrigerants using data mining method. Alternative refrigerants used in the study are R134a, R404a, R407c and R410a. The results obtained from data mining have been compared to actual data from the literature. The study shows that the data mining methodology is successfully applicable to determine enthalpy, entropy and specific volume values for any temperature and pressure of refrigerants. Therefore, computation time reduces and simulation of vapor compression refrigeration systems is fairly facilitated.

Local heat transfer coefficients during boiling of R22 and R407C in horizontal smooth and microfin tubes; Coefficients d'echange locaux au cours de l'ebullition du R22 et du R407C dans des tubes horizontaux, lisse ou micro-ailete

Energy Technology Data Exchange (ETDEWEB)

Lallemand, M; Branescu, C; Haberschill, P [Centre de Thermique, INSA-CNRS, UMR 5008, Villeurbanne (France)

2001-07-01

The purpose of this study is to experimentally investigate forced convective boiling. The heat transfer coefficients of pure refrigerant R22 and non azeotropic refrigerant mixture R407C were measured in both a smooth tube and a microfin tube. The tests have been carried out with a uniform heat flux all along the tube length. The refrigerant mass flux was varied from 100 to 300 kg m{sup -2} s{sup -1} and heat fluxes from 10 to 30 kW m{sup -2}. Local heat transfer coefficient depend strongly on heat flux at a low quality and on mass fluxes at a high quality. When compared to smooth tube, the microfin tubes exhibit a significant heat transfer enhancement, up to 180%. In comparison to R22, the R407C heat transfer coefficients of smooth and microfin tubes are 15 to 35% lower, respectively. The best heat transfer enhancement is obtained at low heat flux and mass flow rate. (Author)

Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler

International Nuclear Information System (INIS)

Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

2014-01-01

A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models

Alternative refrigerants performance in plate heat condenser for air conditioning; Scambiatori compatti per il condizionamento ambientale

Energy Technology Data Exchange (ETDEWEB)

Boccardi, G.; Celata, G.P.; Marchesi Donati, F. [ENEA, Rome (Italy). Inst. of Thermal-Fluid Dynamics; Cumo, M. [Rome Univ. La Sapienza, Rome (Italy). Dept. of Nuclear Engineering and Energy Conversion; Gerosa, A. [Rome Univ. Tor Vergata, Rome (Italy). Dept. of Mechanical Engineering; Zorzin, A. [R and D Alfa Laval Artec Spa Vicenza, Vicenza (Italy)

1999-12-01

An experimental campaign on plate heat exchangers, used as evaporators and condenser in domestic refrigeration loops is presented in this paper. The research's purpose is to test the influence of some thermal-hydraulic parameters on the global overall heat transfer coefficient. R134a, R407C, R410A, and R22 are the fluids tested under reference thermal conditions. The experimental tests allows one to withdraw conclusions on the substitution effect on the thermal and global efficiency of the plant. Also, a new method for calculating the thermodynamical mixture parameters is applied to the condensation of mixtures R407C and R410A and its benefit evaluated. The refrigerant loop overall performance and the condenser global heat transfer coefficient are the parameters chosen to enlighten the characteristics of the alternative refrigerants (R134a, R407C, and R410A) with respect to the fluid that they are supposed to substitute (R22). [Italian] Scambiatori a piastre compatti impiegati come evaporatori e condensatori nei circuiti frigoriferi, sono l'oggetto della ricerca presentata in questo articolo. L'efficienza termica di tali componenti e' valutata in condizioni di riferimento commerciali. I refrigeranti utilizzati sono tre fluidi proposti per sostituire l'R22, un Hcfc, attualmente il refrigerante piu' utilizzato nel condizionamento ambientale. Una serie di prove condotte con quest'ultimo fluido consente di studiare gli effetti della sostituzione del fluido di progetto sulle prestazioni sia degli scambiatori, sia piu' in generale, dell'intero circuito frigorifero. In particolare sono state studiate le prestazioni di due coppie di evaporatori e condensatori in termini di coefficiente globale di scambio termico e di Cop dell'impianto. Nel presente lavoro e' inoltre presentato e utilizzato un metodo termodinamico per il calcolo della temperatura di saturazione per le miscele zeotropiche in bifase; uno dei refrigeranti

Ultimate refrigerating conditions, behavior turning and a thermodynamic analysis for absorption–compression hybrid refrigeration cycle

International Nuclear Information System (INIS)

Zheng Danxing; Meng Xuelin

2012-01-01

Highlights: ► Two novel fundamental concepts of the absorption refrigeration cycle were proposed. ► The interaction mechanism of compressor pressure increasing with other key-parameters was investigated. ► A set of optimal operating condition of hybrid refrigeration cycle was found. ► A simulation and investigation for R134a-DMF hybrid refrigeration cycle was performed. - Abstract: The absorption–compression hybrid refrigeration cycle has been considered as an effective approach to reduce the mechanical work consumption by using low-grade heat, such as solar energy. This work aims at studying the thermodynamic mechanism of the hybrid refrigeration cycle. Two fundamental concepts have been proposed, which are the ultimate refrigerating temperature (or the ultimate temperature lift) and the behavior turning. On the basis of that, the interaction mechanism of compressor pressure increasing with other key-parameters and the impact of compressor pressure increasing on the cycle performance have been investigated. The key-parameters include the concentration difference, the circulation ratio of working fluid, etc. The work points out that the hybrid refrigeration cycle performance varies with the change of compressor outlet pressure and depends on which one achieves dominance in the hybrid refrigeration cycle, the absorption sub-system or the compression sub-system. The behavior turning point during parameters changing corresponds to a maximum value of the heat powered coefficient of performance. In this case, the hybrid refrigeration cycle performance is optimal because the low-grade heat utilization is the most effective. In addition, to validate the theoretical analysis, a solar hybrid refrigeration cycle with R134a–DMF as working pair was simulated. The Peng–Robinson equation of state was adopted to calculate thermophysical properties when the reliability assessment of the prediction models on the available literature data of R134a–DMF system had been

Combined treatment of Thymus vulgaris L., Rosmarinus officinalis L. and Myrtus communis L. essential oils against Salmonella typhimurium: Optimization of antibacterial activity by mixture design methodology.

Science.gov (United States)

Fadil, Mouhcine; Fikri-Benbrahim, Kawtar; Rachiq, Saad; Ihssane, Bouchaib; Lebrazi, Sara; Chraibi, Marwa; Haloui, Taoufik; Farah, Abdellah

2018-05-01

To increase the sensibility of Salmonella typhimurium strain, a mixture of Thymus vulgaris L. (T. vulgaris L.), Rosmarinus officinalis L. (R. officinalis L.) and Myrtus communis L. (M. communis L.) essential oils (EOs) was used in combined treatment by experimental design methodology (mixture design). The chemical composition of EOs was firstly identified by GC and GC/MS and their antibacterial activity was evaluated. The results of this first step have shown that thymol and borneol were the major compounds in T. vulgaris and M. communis L. EOs, respectively, while 1,8-cineole and α-pinene were found as major compounds in R. officinalis L. The same results have shown a strong antibacterial activity of T. vulgaris L. EO followed by an important power of M. communis L. EO against a moderate activity of R. officinalis L. EO. Besides, 1/20 (v/v) was the concentration giving a strain response classified as sensitive. From this concentration, the mixture design was performed and analyzed. The optimization of mixtures antibacterial activities has highlighted the synergistic effect between T. vulgaris L. and M. communis L. essential oils. A formulation comprising 55% of T. vulgaris L. and 45% of M. communis L. essential oils, respectively, can be considered for the increase of Salmonella typhimurium sensibility. Copyright © 2017 Elsevier B.V. All rights reserved.

Prediction of thermophysical properties of mixed refrigerants using artificial neural network

International Nuclear Information System (INIS)

Sencan, Arzu; Koese, Ismail Ilke; Selbas, Resat

2011-01-01

The determination of thermophysical properties of the refrigerants is very important for thermodynamic analysis of vapor compression refrigeration systems. In this paper, an artificial neural network (ANN) is proposed to determine properties as heat conduction coefficient, dynamic viscosity, kinematic viscosity, thermal diffusivity, density, specific heat capacity of refrigerants. Five alternative refrigerants are considered: R413A, R417A, R422A, R422D and R423A. The training and validation were performed with good accuracy. The thermophysical properties of the refrigerants are formulated using artificial neural network (ANN) methodology. Liquid and vapor thermophysical properties of refrigerants with new formulation obtained from ANN can be easily estimated. The method proposed offers more flexibility and therefore thermodynamic analysis of vapor compression refrigeration systems is fairly simplified.

Theoretical research on the performance of the transcritical ejector refrigeration cycle with various refrigerants

International Nuclear Information System (INIS)

Wang, F.; Li, D.Y.; Zhou, Y.

2015-01-01

The transcritical ejector refrigeration cycle (TERC), which has shown an attractive alternative to the ejector refrigeration systems, can better match large variable-temperature heat sources and yields higher COP. In this paper, in order to find a proper working fluid for the TERC, the performance of the TERC with CO_2 and various working fluids with low critical temperatures including R1270, R32, R143a, R125 and R115 are studied and compared. A thermodynamic model for ejector is set up to simulate the ejector by introducing the real properties of refrigerants. The results indicate that R1270 has the highest COP at the same heat source condition and medium working pressures, and is one of environment-friendly working fluids, hence R1270 is the most proper one. The COP of the transcritical cycle is higher than that of the subcritical cycle, and The effective performance coefficient COP_m of the transcritical cycle is also better. When the heater outlet temperature is increased, its system COP_m improves, but its system COP almost does not change. - Highlights: • A thermodynamic model is used to simulate the ejector with real properties. • The performance of the TERC with various refrigerants is compared. • The environment-friendly working fluid of R1270 shows the most proper one. • The COP of the transcritical cycle is higher than that of the subcritical cycle.

Microphase Separation in Oil-Water Mixtures Containing Hydrophilic and Hydrophobic Ions

NARCIS (Netherlands)

Tasios, Nikos; Samin, Sela; van Roij, Rene; Dijkstra, Marjolein

2017-01-01

We develop a lattice-based Monte Carlo simulation method for charged mixtures capable of treating dielectric heterogeneities. Using this method, we study oil-water mixtures containing an antagonistic salt, with hydrophilic cations and hydrophobic anions. Our simulations reveal several phases with a

Catalytic hydrodeoxygenation and hydrocracking of Alcell (R) lignin in alcohol/formic acid mixtures using a Ru/C catalyst

NARCIS (Netherlands)

Kloekhorst, Arjan; Shen, Yu; Yie, Yao; Fang, Ma; Heeres, Hero Jan

The catalytic conversion of Alcell (R) lignin in iso-propanol/formic acid mixtures (1: 1 mass ratio) was explored in a batch set-up using Ru/C as the catalyst (673 K, 4 h, 28% mass lignin intake on solvent). Lignin oils were obtained in good yields (71% mass yields on lignin input) and shown to

Optimization of an Indirect Enzymatic Method for the Simultaneous Analysis of 3-MCPD, 2-MCPD, and Glycidyl Esters in Edible Oils.

Science.gov (United States)

Koyama, Kazuo; Miyazaki, Kinuko; Abe, Kousuke; Ikuta, Keiich; Egawa, Yoshitsugu; Kitta, Tadashi; Kido, Hirotsugu; Sano, Takashi; Takahashi, Yukinari; Nezu, Toru; Nohara, Hidenori; Miyashita, Takashi; Yada, Hiroshi; Yamazaki, Kumiko; Watanabe, Yomi

2015-01-01

We developed a novel, indirect enzymatic method for the analysis of fatty acid esters of 3-monochloro-1,2-propanediol (3-MCPD), 2-monochloro-1,3-propanediol (2-MCPD), and glycidol (Gly) in edible oils and fats. Using this method, the ester analytes were rapidly cleavaged by Candida rugosa lipase at room temperature for 0.5 h. As a result of the simultaneous hydrolysis and bromination steps, 3-MCPD esters, 2-MCPD esters, and glycidyl esters were converted to free 3-MCPD, 2-MCPD, and 3-monobromo-1,2-propanediol (3-MBPD), respectively. After the addition of internal standards, the mixtures were washed with hexane, derivatized with phenylboronic acid, and analyzed by gas chromatography-mass spectrometer (GC-MS). The analytical method was evaluated in preliminary and feasibility studies performed by 13 laboratories. The preliminary study from 4 laboratories showed the reproducibility (RSD R ) of 3-MCPD and 2-MCPD in extra virgin olive (EVO) oil, semi-solid palm oil, and solid palm oil. However, the RSDR and recoveries of Gly in the palm oil samples were not satisfactory. The Gly content of refrigerated palm oil samples decreased whereas the samples at room temperature were stable for three months, and this may be due to the depletion of Gly during cold storage. The feasibility studies performed by all 13 laboratories were conducted based on modifications of the shaking conditions for ester cleavage, the conditions of Gly bromination, and the removal of gel formed by residual lipase. Satisfactory RSDR were obtained for EVO oil samples spiked with standard esters (4.4% for 3-MCPD, 11.2% for 2-MCPD, and 6.6% for Gly).

Modifications to JLab 12 GeV Refrigerator and Wide Range Mix Mode Performance Testing Results

Science.gov (United States)

Knudsen, P.; Ganni, V.; Hasan, N.; Dixon, K.; Norton, R.; Creel, J.

2017-02-01

Analysis of data obtained during the spring 2013 commissioning of the new 4.5 K refrigeration system at Jefferson Lab (JLab) for the 12 GeV upgrade indicated a wide capacity range with good efficiency and minimal operator interaction. Testing also showed that the refrigerator required higher liquid nitrogen (LN) consumption for its pre-cooler than anticipated by the design. This does not affect the capacity of the refrigerator, but it does result in an increased LN utility cost. During the summer of 2015 the modifications were implemented by the cold box manufacturer, according to a design similar to the JLab 12 GeV cold box specification. Subsequently, JLab recommissioned the cold box and performed extensive performance testing, ranging from 20% to 100% of the design maximum capacity, and in various modes of operation, ranging from pure refrigeration, pure liquefaction, half-and-half mix mode and at selected design modes using the Floating Pressure - Ganni Cycle. The testing demonstrated that the refrigerator system has a good and fairly constant performance over a wide capacity range and different modes of operation. It also demonstrated the modifications resulted in a LN consumption that met the design for the pure refrigeration mode (which is the most demanding) and was lower than the design for the nominal and maximum capacity modes. In addition, a pulsed-load test, similar to what is expected for cryogenic systems supporting fusion experiments, was conducted to observe the response using the Floating Pressure - Ganni Cycle, which was stable and robust. This paper will discuss the results and analysis of this testing pertaining to the LN consumption, the system efficiency over a wide range of capacity and different modes and the behaviour of the system to a pulsed load.

Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC/R), AFSC 3E1X1. OSSN 2368

National Research Council Canada - National Science Library

1999-01-01

Survey Coverage: The Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC/R) career ladder, AFSC 3E1X1, was surveyed to gather data needed to guide the development and evaluation of training...

ENZYMATIC BIODIESEL SYNTHESIS FROM ACID OIL USING A LIPASE MIXTURE

Directory of Open Access Journals (Sweden)

Kelly C. N. R. Pedro

Full Text Available The conventional biodiesel production process has some disadvantages. It is necessary to use refined vegetable oils with low free fatty acids (FFAs content. An alternative route is to use low-cost acid oils in an enzymatic process. The use of lipases allows simultaneous esterification of FFAs and transesterification of triglycerides present in raw material forming alkyl esters. The aim of this work was to study the production of biodiesel using soybean oils with different acid contents (Acid Value of 8.5, 50, 90 and ethanol catalyzed by commercial immobilized lipases (Novozym 435, Lipozyme RM IM and Lipozyme TL IM. A significant decrease of acid value was observed mainly with Novozym 435 and Lipozyme RM IM. The use of a mixture of two immobilized lipases was also investigated to decrease catalyst cost and increase the amount of ester produced. The three commercial immobilized lipases were mixed in a dual system and tested for biodiesel synthesis from acid oil (AV of 8.5, 50 and 90. A positive synergistic effect occurred mainly for Lipozyme TL IM (1,3-specific lipase and Novozym 435 (non-specific lipase blend. The ester content doubled when this lipase mixture was used in ethanolysis of acid oil with AV of 90.

Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions.

Science.gov (United States)

Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

2017-02-20

Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m -2 h -1 bar -1 -a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

An Evaluation of the Environmental Impact of Different Commercial Supermarket Refrigeration Systems Using Low Global Warming Potential Refrigerants

Energy Technology Data Exchange (ETDEWEB)

Beshr, Mohamed [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Radermacher, Reinhard [University of Maryland, College Park

2014-01-01

Commercial refrigeration systems consumed 1.21 Quads of primary energy in 2010 and are known to be a major source for refrigerant charge leakage into the environment. Thus, it is important to study the environmental impact of commercial supermarket refrigeration systems and improve their design to minimize any adverse impacts. The system s Life Cycle Climate Performance (LCCP) was presented as a comprehensive metric with the aim of calculating the equivalent mass of carbon dioxide released into the atmosphere throughout its lifetime, from construction to operation and destruction. In this paper, an open source tool for the evaluation of the LCCP of different air-conditioning and refrigeration systems is presented and used to compare the environmental impact of a typical multiplex direct expansion (DX) supermarket refrigeration systems based on three different refrigerants as follows: two hydrofluorocarbon (HFC) refrigerants (R-404A, and R-407F), and a low global warming potential (GWP) refrigerant (N-40). The comparison is performed in 8 US cities representing different climates. The hourly energy consumption of the refrigeration system, required for the calculation of the indirect emissions, is calculated using a widely used building energy modeling tool (EnergyPlus). A sensitivity analysis is performed to determine the impact of system charge and power plant emission factor on the LCCP results. Finally, we performed an uncertainty analysis to determine the uncertainty in total emissions for both R-404A and N-40 operated systems. We found that using low GWP refrigerants causes a considerable drop in the impact of uncertainty in the inputs related to direct emissions on the uncertainty of the total emissions of the system.

Efficiency analysis of alternative refrigerants for ejector cooling cycles

International Nuclear Information System (INIS)

Gil, Bartosz; Kasperski, Jacek

2015-01-01

Highlights: • Advantages of using alternative refrigerants as ejector refrigerants were presumed. • Computer software basing on theoretical model of Huang et al. (1999) was prepared. • Optimal temperature range of primary vapor for each working fluid was calculated. - Abstract: Computer software, basing on the theoretical model of Huang et al. with thermodynamic properties of selected refrigerants, was prepared. Investigation was focused on alternative refrigerants that belong to two groups of substances: common solvents (acetone, benzene, cyclopentane, cyclohexane and toluene) and non-flammable synthetic refrigerants applied in Organic Rankine Cycle (ORC) (R236ea, R236fa, R245ca, R245fa, R365mfc and RC318). Refrigerants were selected to detect a possibility to use them in ejector cooling system powered by a high-temperature heat source. A series of calculations were carried out for the generator temperature between 70 and 200 °C, with assumed temperatures of evaporation 10 °C and condensation 40 °C. Investigation revealed that there is no single refrigerant that ensures efficient operation of the system in the investigated temperature range of primary vapor. Each substance has its own maximum entrainment ratio and COP at its individual temperature of the optimum. The use of non-flammable synthetic refrigerants allows obtaining higher COP in the low primary vapor temperature range. R236fa was the most beneficial among the non-flammable synthetic refrigerants tested. The use of organic solvents can be justified only for high values of motive steam temperature. Among the solvents, the highest values of entrainment ratio and COP throughout the range of motive temperature were noted for cyclopentane. Toluene was found to be an unattractive refrigerant from the ejector cooling point of view

Cytotoxic and antibacterial activity of the mixture of olive oil and lime cream in vitro conditions.

Science.gov (United States)

Sumer, Zeynep; Yildirim, Gulay; Sumer, Haldun; Yildirim, Sahin

2013-01-01

The mixture of olive oil and lime cream has been traditionally used to treat external burns in the region of Hatay/Antakya and middle Anatolia. Olive oil and lime cream have been employed by many physicians to treat many ailments in the past. A limited number of studies have shown the antibacterial effect of olive oil and that it does not have any toxic effect on the skin. But we did not find any reported studies on the mixture of olive oil and lime cream. The aim of this paper is to investigate the cytotoxic and antibacterial activity of olive oil and lime cream individually or/and in combination in vitro conditions, by using disk-diffusion method and in cell culture. The main purpose in using this mixture is usually to clear burns without a trace. Agar overlay, MTT (Cytotoxicity assay) and antibacterial susceptibility tests were used to investigate the cytotoxic and antibacterial activity of olive oil and lime cream. We found that lime cream has an antibacterial activity but also cytotoxic on the fibroblasts. On the other hand olive oil has limited or no antibacterial effect and it has little or no cytotoxic on the fibroblasts. When we combined lime cream and olive oil, olive oil reduced its cytotoxic impact. These results suggest that mixture of olive oil and lime cream is not cytotoxic and has antimicrobial activity.

Case Study of R-1234yf Refrigerant: Implications for the Framework for Responsible Innovation.

Science.gov (United States)

Wodzisz, Rafał

2015-12-01

Safety and care for the natural environment are two of the most important values that drive scientific enterprise in twentieth century. Researchers and innovators often develop new technologies aimed at pollution reduction, and therefore satisfy the strive for fulfilment of these values. This work is often incentivized by policy makers. According to EU directive 2006/40/EC on mobile air conditioning since 2013 all newly approved vehicles have to be filled with refrigerant with low global warming potential (GWP). Extensive and expensive research financed by leading car manufacturers led to invention of R-1234yf refrigerant with GWP marketing. Secondly, I examine framework for responsible innovation. In greater detail I discuss the notions of care for future generations and collective responsibility. Thirdly, I apply the offered framework to the case study at hand. Finally, I draw some conclusions which go in two directions: one is to make some suggestions for improving the framework of RI, and the second is to identify missed opportunities for developing truly responsible refrigerant.

Compatibility of refrigerants and lubricants with elastomers. Final report

Energy Technology Data Exchange (ETDEWEB)

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

1994-01-01

The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. In part I of the program the swell behavior in the test fluids has been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed fro the refrigerant test fluids and 24 hours after removal from the lubricants. Part II of the testing program includes the evaluation of tensile strength, hardness, weight, and dimensional changes after immersion aging in refrigerant/lubricant mixtures of selected elastomer formulations at elevated temperature and pressure.

Substitution of R502 in existing refrigerating, air-conditioning and heat pump systems with refrigerants of low ozone depletion potential in the Federal Republic of Germany; Ersatz von R 502 in bestehenden Kaelte-, Klima- und Waermepumpenanlagen in der Bundesrepublik Deutschland durch Kaeltemittel mit geringerem Ozonabbaupotential

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-06-01

The technical basics and the state of engineering for the substitution of R502 in existing refrigeration systems are described and explained. The report contains an overview of the current applications of R502 in the FRG, the presentation and discussion of existing substitutes, the presentation and valuations of research and experiences with the adaptation to alternative refrigerants, the presentation of the required infrastructure and a discussion of the technical feasibility. The conversion of existing systems to refrigerants of lower ozone depletion potential is in conclusion valuated with regard to its technical feasibility, environmental relevance and economic efficiency. (orig.) [Deutsch] Es werden die technischen Grundlagen und der Stand der Technik zum Ersatz von R502 in bestehenden Kaelteanlagen dargestellt und erlaeutert. Der Bericht beinhaltet einen Ueberblick ueber die derzeitige Anwendung von R502 in der BRD, die Vorstellung und Diskussion existierender Ersatzstoffe, die Darstellung und Bewertung der Forschung und Erfahrungen zu Umruestungen auf Ersatzstoffe, die Vorstellung der erforderlichen Infrastruktur und die Diskussion der technischen Durchfuehrbarkeit. Die Umstellung bestehender Anlagen auf Kaeltemittel mit geringerem Ozonabbaupotential wird abschliessend hinsichtlich der technischen Durchfuehrbarkeit, der Umweltrelevanz und der Wirtschaftlichkeit bewertet. (orig.)

Data mining techniques for thermophysical properties of refrigerants

International Nuclear Information System (INIS)

Kuecueksille, Ecir Ugur; Selbas, Resat; Sencan, Arzu

2009-01-01

This study presents ten modeling techniques within data mining process for the prediction of thermophysical properties of refrigerants (R134a, R404a, R407c and R410a). These are linear regression (LR), multi layer perception (MLP), pace regression (PR), simple linear regression (SLR), sequential minimal optimization (SMO), KStar, additive regression (AR), M5 model tree, decision table (DT), M5'Rules models. Relations depending on temperature and pressure were carried out for the determination of thermophysical properties as the specific heat capacity, viscosity, heat conduction coefficient, density of the refrigerants. Obtained model results for every refrigerant were compared and the best model was investigated. Results indicate that use of derived formulations from these techniques will facilitate design and optimize of heat exchangers which is component of especially vapor compression refrigeration system

Comparison of a R744 cascade refrigeration system with R404A and R22 conventional systems for supermarkets

International Nuclear Information System (INIS)

Silva, Alessandro da; Pedone Bandarra Filho, Enio; Pontes Antunes, Arthur Heleno

2012-01-01

The present article focuses on the energy efficiency and climate performance of three different systems used in supermarket applications. The refrigeration systems consist of a cascade cycle (CO 2 /HFC-404A) – provide nominal refrigerating capacity – with carbon dioxide for subcritical operation and HFC-404A in the high stage temperature stage (pump circuit for normal refrigeration and direct expansion for deep-freezing), and also HFC-404A and HCFC-22 with direct expansion systems. The cascade system presented a lower refrigerant charge, 47 kg of both fluids, which represents less than a half of the refrigerant charge of the other systems. An important factor is the total GWP in case of leakage, where the impact in the atmosphere of the cascade system operating with CO 2 was much less than the two direct expansion systems.

Estimating animal abundance with N-mixture models using the R-INLA package for R

KAUST Repository

Meehan, Timothy D.

2017-05-03

Successful management of wildlife populations requires accurate estimates of abundance. Abundance estimates can be confounded by imperfect detection during wildlife surveys. N-mixture models enable quantification of detection probability and often produce abundance estimates that are less biased. The purpose of this study was to demonstrate the use of the R-INLA package to analyze N-mixture models and to compare performance of R-INLA to two other common approaches -- JAGS (via the runjags package), which uses Markov chain Monte Carlo and allows Bayesian inference, and unmarked, which uses Maximum Likelihood and allows frequentist inference. We show that R-INLA is an attractive option for analyzing N-mixture models when (1) familiar model syntax and data format (relative to other R packages) are desired, (2) survey level covariates of detection are not essential, (3) fast computing times are necessary (R-INLA is 10 times faster than unmarked, 300 times faster than JAGS), and (4) Bayesian inference is preferred.

Ammonia-a refrigerant in the past and present, more and more in the future

International Nuclear Information System (INIS)

Ciconkov, Risto; Lindborg, Anders

2000-01-01

The harmful influence on the global climate of CFCs (R11, R12, R502) and HCFCs (R22) refrigerants causes the depletion of the stratospheric ozone and the greenhouse effect. The international activity for the phase-out of the ozone depletion substances (ODSS) is the Montreal Protocol. The alternative refrigerants on the market are natural working fluids: ammonia, hydrocarbons (HCs), carbon dioxide, water and air. HFCs are for some applications the alternatives for CFC/HCFCs and have no ozone depletion (ODP=O), but the HFCs are greenhouse gases and have GWP and are regulated in the Kyoto Protocol. Ammonia has been in use for more than 125 years. The advantages of ammonia are excellent thermodynamic and heat transport properties, but ammonia is regarded as toxic and flammable. The ammonia refrigerating systems are liable under codes and standards, which shall be followed. With better knowledge and understanding, good practice and right comprehension of people involved in ammonia refrigeration, this refrigerant is a winner. There are many research projects and activities in order to widen the use of ammonia in the applications where CFC/HCFCs were used in the past. Regarding to this trend, it is a paradoxical situation in Macedonia and other developing countries where ammonia systems of cold stores, diaries, breweries and food processing go out of use. (Author)

Energetic analysis of a commercial absorption refrigeration unit using an ammonia-water mixture

Directory of Open Access Journals (Sweden)

Josegil Jorge de Araújo

2017-09-01

Full Text Available The ROBUR® absorption refrigeration system (ARS, model ACF60, with a capacity of 17.5 kW, is tested, modeled and simulated in the steady state. To simulate the thermal load a heating system with secondary coolant was used, in which a programmable logic controller (PLC kept the inlet temperature EVA at around 285.15 K. The mathematical model used was based on balancing the mass, energy and ammonia concentrations and completed by closing equations such as, Newton's cooling equation. The mathematical model was implemented using the Engineering Equation Solver – EES®. The results obtained after modeling and a numerical permanent simulation are studied using the Duhring diagram. Potential points of internal heat recovery are visualized, and by using graphs of the binary mixture, it is possible to identify the thermodynamic states of all monitored points. The data obtained in the numerical simulation of the ARS was compared with data acquired in the actual tests of the ARS with the ROBUR® apparatus.

Energy and exergy analysis of LPG (liquefied petroleum gas) as a drop in replacement for R134a in domestic refrigerators

International Nuclear Information System (INIS)

El-Morsi, Mohamed

2015-01-01

This study presents a comparison of energetic and exergetic performance of a vapour compression refrigeration system using pure HC (hydrocarbon) refrigerants. In this study, three different pure HCs propane (R290), butane (R600) and commercial LPG (liquefied petroleum gas) are used in the theoretical analysis. R134a is also used in the analysis as a reference refrigerant. The evaporator temperature ranges from −30 to 0 °C while the condenser ranges from 30 to 50 °C. MATLAB software is used for solving the thermodynamic equations, while the thermo-physical properties are calculated using REFPROP software. The results show that R600 has the highest COP c and exergetic efficiency, while LPG has the lowest. When compared to R134a, the COP c for R134a is higher than that for LPG by 10%. Also, the exergetic efficiency is higher by 5%. However, LPG has the advantage of being not expensive, available in large amounts and zero ozone depletion potential and low global warming potential. - Highlights: • The results show that R600 has the highest COP c & exergy efficiency, and the lowest irreversibility. • LPG has the lowest COP c & exergy efficiency, and the highest irreversibility. • Compared to R134a, LPG has a lower COP c and exergy efficiency by an average of 10% and 5%, respectively

A review of linear compressors for refrigeration

OpenAIRE

Liang, Kun

2017-01-01

Linear compressor has no crank mechanism compared with conventional reciprocating compressor. This allows higher efficiency, oil-free operation, lower cost and smaller size when linear compressors are used for vapour compression refrigeration (VCR) system. Typically, a linear compressor consists of a linear motor (connected to a piston) and suspension springs, operated at resonant frequency. This paper presents a review of linear compressors for refrigeration system. Different designs and mod...

Investigation of the mixture flow rates of oil-water two-phase flow using the turbine flow meter

International Nuclear Information System (INIS)

Li Donghui; Feng Feifei; Wu Yingxiang; Xu Jingyu

2009-01-01

In this work, the mixture flow rate of oil-water flows was studied using the turbine flow-meter. The research emphasis focuses on the effect of oil viscosity and input fluids flow rates on the precision of the meter. Experiments were conducted to measure the in-situ mixture flow rate in a horizontal pipe with 0.05m diameter using seven different viscosities of white oil and tap water as liquid phases. Results showed that both oil viscosity and input oil fraction exert a remarkable effect on measured results, especially when the viscosity of oil phase remained in the area of high value. In addition, for metering mixture flow rate using turbine flow-meter, the results are not sensitive to two-phase flow pattern according to the experimental data.

Theoretical analysis of ejector refrigeration system performance under overall modes

International Nuclear Information System (INIS)

Chen, Weixiong; Shi, Chaoyin; Zhang, Shuangping; Chen, Huiqiang; Chong, Daotong; Yan, Junjie

2017-01-01

Highlights: • Real gas theoretical model is used to get ejector performance at critical/sub-critical modes. • The model has a better accuracy against the experiment results compared to ideal gas model. • The overall performances of two refrigerants are analyzed based on the parameter analysis. - Abstract: The ejector refrigeration integrated in the air-conditioning system is a promising technology, because it could be driven by the low grade energy. In the present study, a theoretical calculation based on the real gas property is put forward to estimate the ejector refrigeration system performance under overall modes (critical/sub-critical modes). The experimental data from literature are applied to validate the proposed model. The findings show that the proposed model has higher accuracy compared to the model using the ideal gas law, especially when the ejector operates at sub-critical mode. Then, the performances of the ejector refrigeration circle using different refrigerants are analyzed. R290 and R134a are selected as typical refrigerants by considering the aspects of COP, environmental impact, safety and economy. Finally, the ejector refrigeration performance is investigated under variable operation conditions with R290 and R134a as refrigerants. The results show that the R290 ejector circle has higher COP under critical mode and could operate at low evaporator temperature. However, the performance would decrease rapidly at high condenser temperature. The performance of R134a ejector circle is the opposite, with relatively lower COP, and higher COP at high condenser temperature compared to R290.

Efficiency improvement of commercial refrigeration systems

Energy Technology Data Exchange (ETDEWEB)

Denecke, Julius [NTNU, Trondheim (Norway); Hafner, Armin [SINTEF Energy Research, Trondheim (Norway)

2011-07-01

This work presents a historical review of carbon dioxide refrigeration systems. Further a literature survey is carried out to get a status of existing refrigeration technology related to supermarkets. In the next step various energy saving options are stated. A heat recovery model, basing on a R744 booster refrigeration system is established and described. Simplified demand curves for refrigeration, air conditioning and heating will base this model to calculate different heat recovery layouts. Supermarket future trends will be considered and integrated in the calculation. Finally the calculated energy consumptions will be compared with real energy consumptions of selected supermarket refrigeration systems.

Molecular and structural changes induced by essential oils treatments in Vicia faba roots detected by genotoxicity testing.

Science.gov (United States)

Sturchio, Elena; Boccia, Priscilla; Zanellato, Miriam; Meconi, Claudia; Donnarumma, Lucia; Mercurio, Giuseppe; Mecozzi, Mauro

2016-01-01

Over the last few years, there has been an increased interest in exploiting allelopathy in organic agriculture. The aim of this investigation was to examine the effects of essential oil mixtures in order to establish their allelopathic use in agriculture. Two mixtures of essential oils consisting respectively of tea tree oil (TTO) and clove plus rosemary (C + R) oils were tested. Phytotoxicity and genotoxicity tests on the root meristems of Vicia faba minor were performed. A phytotoxic influence was particularly relevant for C + R mixture, while genotoxicity tests revealed significant results with both C + R oil mixture and TTO. Phenotypic analysis on Vicia faba minor primary roots following C + R oil mixture treatment resulted in callose production, an early symptom attributed to lipid peroxidation. The approach described in this study, based on genotoxicity bioassays, might identify specific DNA damage induced by essential oil treatments. These tests may represent a powerful method to evaluate potential adverse effects of different mixtures of essential oils that might be useful in alternative agriculture. Future studies are focusing on the positive synergism of more complex mixtures of essential oils in order to reduce concentrations of potentially toxic components while at the same time maintaining efficacy in antimicrobial and antifungal management.

Estimation of the minimum Prandtl number for binary gas mixtures formed with light helium and certain heavier gases: Application to thermoacoustic refrigerators

International Nuclear Information System (INIS)

Campo, Antonio; Papari, Mohammad M.; Abu-Nada, Eiyad

2011-01-01

This paper addresses a detailed procedure for the accurate estimation of low Prandtl numbers of selected binary gas mixtures. In this context, helium (He) is the light primary gas and the heavier secondary gases are nitrogen (N 2 ), oxygen (O 2 ), xenon (Xe), carbon dioxide (CO 2 ), methane (CH 4 ), tetrafluoromethane or carbon tetrafluoride (CF 4 ) and sulfur hexafluoride (SF 6 ). The three thermophysical properties forming the Prandtl number of binary gas mixtures Pr mix are heat capacity at constant pressure C p,mix (thermodynamic property), viscosity η mix (transport property) and thermal conductivity λ mix (transport property), which in general depend on temperature T and molar gas composition w. The precise formulas for the calculation of the trio C p,mix , η mix , and λ mix are gathered from various dependable sources. When the set of computed Pr mix values for the seven binary gas mixtures He + N 2 , He + O 2 , He + Xe, He + CO 2 , He + CH 4 , He + CF 4 , He + SF 6 at atmospheric conditions T = 300 K, p = 1 atm is plotted against the molar gas composition w on the w-domain [0,1], the family of Pr mix (w) curves exhibited distinctive concave shapes. In the curves format, all Pr mix (w) curves initiate with Pr ∼ 0.7 at w = 0 (associated with light primary He). Forthwith, each Pr mix (w) curve descends to a unique minimum and thereafter ascend back to Pr ∼ 0.7 at the terminal point w = 1 (connected to heavier secondary gases). Overall, it was found that among the seven binary gas mixtures tested, the He + Xe gas mixture delivered the absolute minimum Prandtl number Pr mix,min = 0.12 at the optimal molar gas composition w opt = 0.975. - Highlights: →Accurate estimation of low Prandtl numbers for some helium-based binary gas mixtures. →The thermophysical properties of the gases are calculated with precise formulas. →The absolute minimum Prandtl number is delivered by the He + Xe binary gas mixture. →Application to experimental thermoacoustic

Experimental study on a prototype of heat pipe solar water heater using refrigerant R134a as a transfer fluid

Science.gov (United States)

Sitepu, T.; Sembiring, J.; Ambarita, H.

2018-02-01

A prototype of a solar water heater by using refrigerant as a heat transfer fluid is investigated experimentally. The objective is to explore the characteristics and the performance of the prototype. To make heat transfer from the collector to the heated fluid effectively, refrigerant R134a is used as a transfer. In the experiments, the initial pressure inside the heat pipe is varied. The prototype is exposed to solar irradiation in a location in Medan city for three days of the experiment. Solar collector temperatures, solar radiation, water temperature, and ambient temperature are measured. The efficiency of the system is analyzed. The results show that temperature of the hot water increases as the initial pressure of the working fluid increase. However, the increasing is not linear, and there must exist an optimum initial pressure. For the case with the refrigerant pressure of 110 psi, the maximum hot water temperature and maximum thermal efficiency are 45.36oC and 53.23%, respectively. The main conclusion can be drawn here is that solar water heater by using refrigerant R134a should be operated at initial pressure 110 psi.

Development of Low Global Warming Potential Refrigerant Solutions for Commercial Refrigeration Systems using a Life Cycle Climate Performance Design Tool

Energy Technology Data Exchange (ETDEWEB)

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

2012-01-01

Commercial refrigeration systems are known to be prone to high leak rates and to consume large amounts of electricity. As such, direct emissions related to refrigerant leakage and indirect emissions resulting from primary energy consumption contribute greatly to their Life Cycle Climate Performance (LCCP). In this paper, an LCCP design tool is used to evaluate the performance of a typical commercial refrigeration system with alternative refrigerants and minor system modifications to provide lower Global Warming Potential (GWP) refrigerant solutions with improved LCCP compared to baseline systems. The LCCP design tool accounts for system performance, ambient temperature, and system load; system performance is evaluated using a validated vapor compression system simulation tool while ambient temperature and system load are devised from a widely used building energy modeling tool (EnergyPlus). The LCCP design tool also accounts for the change in hourly electricity emission rate to yield an accurate prediction of indirect emissions. The analysis shows that conventional commercial refrigeration system life cycle emissions are largely due to direct emissions associated with refrigerant leaks and that system efficiency plays a smaller role in the LCCP. However, as a transition occurs to low GWP refrigerants, the indirect emissions become more relevant. Low GWP refrigerants may not be suitable for drop-in replacements in conventional commercial refrigeration systems; however some mixtures may be introduced as transitional drop-in replacements. These transitional refrigerants have a significantly lower GWP than baseline refrigerants and as such, improved LCCP. The paper concludes with a brief discussion on the tradeoffs between refrigerant GWP, efficiency and capacity.

Study of change of refrigerant R{sub 2}2 in chiller units by simulation in EcosimPro; Estudio de cambio de gas refriferante R{sub 2}2 en unidades enfriadoras mediante simulacion en EcosimPro

Energy Technology Data Exchange (ETDEWEB)

Prieto, J.; Molina, C.; Olmedo, J.; Gavilan, C. J.

2014-07-01

On January 1, 2010 is forbidden to hold any stock of virgin R{sub 2}2 refrigerant and it is also forbidden to use virgin R{sub 2}2 refrigerant for the service and maintenance of equipment under the new European Community Regulation 20137/2000. On January 1, 2015 and stock of R{sub 2}2, even if reclaimed or recycled, will be illegal to hold. In accordance with the European Community regulation, Cofrentes Nuclear Power Plant begins the R{sub 2}2 retrofit. (Author)

mixtools: An R Package for Analyzing Mixture Models

Directory of Open Access Journals (Sweden)

Tatiana Benaglia

2009-10-01

Full Text Available The mixtools package for R provides a set of functions for analyzing a variety of finite mixture models. These functions include both traditional methods, such as EM algorithms for univariate and multivariate normal mixtures, and newer methods that reflect some recent research in finite mixture models. In the latter category, mixtools provides algorithms for estimating parameters in a wide range of different mixture-of-regression contexts, in multinomial mixtures such as those arising from discretizing continuous multivariate data, in nonparametric situations where the multivariate component densities are completely unspecified, and in semiparametric situations such as a univariate location mixture of symmetric but otherwise unspecified densities. Many of the algorithms of the mixtools package are EM algorithms or are based on EM-like ideas, so this article includes an overview of EM algorithms for finite mixture models.

Situation and perspectives in refrigerating and air-conditioning. The point of view of Elf Atochem; Situation et perspectives en refrigeration et air conditionne. Point de vue d`Elf Atochem

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

This paper is a series of transparencies which explains the engagements of Elf Atochem company in the replacement of chlorofluorocarbons (CFCs): development of HFCs, production of FORANE, safety and environmental criteria, main refrigerants and their application in new installations, perspectives in reconversion, replacement of R-22, CFC-12 and R-502 fluids with respect to their applications. (J.S.)

Studies on The Synergistic Effect of Some Irradiated Essential Oils in Some Food Products

International Nuclear Information System (INIS)

Hanafy, M.A.A.

2013-01-01

Cumin, rosemary and thyme essential oils were gamma irradiated. Then, antibacterial and antioxidant activities were studied to measure the synergistic effect of their essential oils mixtures. 4, 6 and 4 kGy were the recommended doses for cumin, rosemary and thyme, respectively according to antimicrobial activity (agar well-diffusion) against S. typhimurium, S. aureus, B. cereus and E. coli. There were no changes in the physiochemical properties due to irradiation but, some changes occurred in the GC/MS analysis where, the amount of oxygenated compounds increased in cumin and thyme essential oils while, the oxygenated compounds decreased in rosemary essential oil. The mixture made from non-irradiated cumin (C 0 ) and rosemary (R 0 ) essential oils were showed the highest antimicrobial activity against E. coil and B. cereus at 50 μl. Mixtures made from non-irradiated cumin and thyme (T 0 ) essential oils showed the highest antimicrobial activity against B. cereus. Mixtures made form irradiated cumin at dose 4 kGy (C 4 ) and rosemary at dose 6 kGy (R 6 ) essential oils introduced promising antimicrobial activity as well as C 0 XR 0 mixture. Fraction inhibitory concentrations (FIC) were studied against selected four bacterial strains for measuring synergistic activity however, (FIC) represented indifference in all essential oils mixtures but, the C 0 X R 0 mixture against B. cereus (0.375) and E. coli (0.375) was synergy (below 0.5). Furthermore, the FIC shows addition in case of R 0 XT 0 , C 2 XR 6 , C 4 XR 6 and R 6 XT 4 against B. cereus. And in case of C 4 XR 6 against S. typhimurium. Preliminary experiment represented that 0.2, 0.4 and 0.1% were the acceptable odor in sunflower oil supplemented with rosemary, cumin and thyme essential oils, respectively.

Thermodynamic analysis of hydrocarbon refrigerants-based ethylene BOG re-liquefaction system

Science.gov (United States)

Beladjine, Boumedienne M.; Ouadha, Ahmed; Addad, Yacine

2016-09-01

The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane (R290), butane (R600), isobutane (R600a), and propylene (R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system's performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600a gives the best performance, followed by (in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.

Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol–methanol mixtures

Energy Technology Data Exchange (ETDEWEB)

Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

2014-12-15

Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.

Impact of Flax Seed and Canola Oils Mixture Supplementation on The Physiological and Biochemical Changes Induced by Monosodium Glutamate in Rats

International Nuclear Information System (INIS)

Anwar, M.M.; Mohamed, N.E.

2010-01-01

One of the most important problems in the human health nutrition field is the use of food flavor. Monosodium glutamate is one of the main flavors used as an ingredient in various food products, however it produces physiological and biochemical changes. The main objective of this study is to evaluate the supplementation of flax seed and canola oils mixture against the physiological and biochemical changes induced by monosodium glutamate in rats. In addition to analyses the physical and chemical characteristics of flax seed and canola oil and fatty acids composition by using gas liquid chromatography. The results concerning that unsaturated fatty acids of flax seed oil were oleic (18:1) 22%, linoleic acid (18:2) 30 % and linolenic acid (18:3) 36%. Total unsaturated fatty acids percentage in flaxseed oil was 88% and total saturated fatty acids 12%. The unsaturated fatty acids of canola oil were oleic (18:1) 66%, linoleic acid (18:2) 18% and linolenic acid (18:3) 7%, total unsaturated fatty acids percentage in canola oil was 92% and total saturated fatty acids was 8%. On the other hand, treatment of rats with monosodium glutamate for ten consecutive days led to a decrease in RBCs, Hb, Hct % and increased platelet count with decrease in WBCs and undesirable changes in its differential count. There is also, high significant increase in testicular thiobarbituric acid reactive substances (TBARS) which is accompanied with significant reduction in catalase (CAT) activity, reduced glutathione (GSH) content and serum testosterone level. These disturbances were associated with significant increase in the liver enzymes ALT,AST and ALP and increase in the level of total biluribin and glucose. Also, significant increase in urea, creatinine and uric acid were recorded. The supplementation with mixture of flax seed and canola oils mixture for one month after the injection of monosodium glutamate caused noticeable amelioration in the damage occurred as a result of this flavor. To

Exergy analysis of vapor compression refrigeration cycle with two-stage and intercooler

Energy Technology Data Exchange (ETDEWEB)

Kilic, Bayram [Mehmet Akif Ersoy University, Bucak Emin Guelmez Vocational School, Bucak, Burdur (Turkey)

2012-07-15

In this study, exergy analyses of vapor compression refrigeration cycle with two-stage and intercooler using refrigerants R507, R407c, R404a were carried out. The necessary thermodynamic values for analyses were calculated by Solkane program. The coefficient of performance, exergetic efficiency and total irreversibility rate of the system in the different operating conditions for these refrigerants were investigated. The coefficient of performance, exergetic efficiency and total irreversibility rate for alternative refrigerants were compared. (orig.)

Development of a low-temperature refrigerant on the basis of carbon dioxide; Entwicklung eines Tieftemperaturkaeltemittels auf Basis von Kohlendioxid

Energy Technology Data Exchange (ETDEWEB)

Goepfert, Tobias; Hesse, Ullrich [Technische Univ. Dresden (Germany). Bitzer-Stiftungsprofessur fuer Kaelte-, Kryo- und Kompressorentechnik

2014-07-01

With the help of known substance properties and derived calculation correlations the mixtures were identified on the basis of R744, which are suitable as a cryogenic refrigerant in the range -50 to -100 degrees Celsius. A prediction and assessment of the suitability of the mixtures is made and the still unknown material properties are shown, which are required for detailed evaluation. [German] Mit Hilfe von bekannten Stoffeigenschaften und abgeleiteten Berechnungskorrelationen wurden Gemische auf der Basis von R744 identifiziert, welche sich als Tieftemperaturkaeltemittel im Bereich von -50 bis -100 Grad Celsius eigenen. Es wird eine Prognose und Abschaetzung der Eignung der Stoffgemische vorgenommen und es werden die noch unbekannten Stoffeigenschaften dargestellt, die zur genauen Bewertung benoetigt werden.

Influence of the nozzle angle on refrigeration performance of a gas wave refrigerator

Science.gov (United States)

Liu, P.; Zhu, Y.; Wang, H.; Zhu, C.; Zou, J.; Wu, J.; Hu, D.

2017-05-01

A gas wave refrigerator (GWR) is a novel refrigerating device that refrigerates a medium by shock waves and expansion waves generated by gas pressure energy. In a typical GWR, the injection energy losses between the nozzle and the expansion tube are essential factors which influence the refrigeration efficiency. In this study, numerical simulations are used to analyze the underlying mechanism of the injection energy losses. The results of simulations show that the vortex loss, mixing energy loss, and oblique shock wave reflection loss are the main factors contributing to the injection energy losses in the expansion tube. Furthermore, the jet angle of the gas is found to dominate the injection energy losses. Therefore, the optimum jet angle is theoretically calculated based on the velocity triangle method. The value of the optimum jet angle is found to be 4^{circ }, 8^{circ }, and 12^{circ } when the refrigeration efficiency is the first-order, second-order, and third-order maximum value over all working ranges of jet frequency, respectively. Finally, a series of experiments are conducted with the jet angle ranging from -4^{circ } to 12^{circ } at a constant expansion ratio. The results indicate the optimal jet angle obtained by the experiments is in good agreement with the calculated value. The isentropic refrigeration efficiency increased by about 4 % after the jet angle was optimized.

Burn drug made from ozonated vegetable oil mixture with white tumeric and cassava leaves extract

Directory of Open Access Journals (Sweden)

Moulydia Farah

2018-01-01

Full Text Available This research aims to create a burn treatment performed with ozonation process from a mixture of vegetable oil and added extracts of herbal ingredients. Ozonation on vegetable oils proven to kill bacteria and safe for the body. Ozonated vegetable oil produced from the ozone reactor batch process by doing a variety of extraction mixture to Oleozon® and vegetable oils. Then the results of ozonation is added extracts of herbal ingredients that cassava leaves and white turmeric to increase effectiveness in killing bacteria. Cassava leaves have anti-inflammatory agent, namely Vitamin C. While white turmeric Curcuma zedoaria have substance, which of the two compounds can inhibit and kill bacteria. The quality of ozonated oil (Oleozon® analytically were tested by the method of iodine number, acid number, peroxide number, and FTIR. Ozonation increased the peroxide and acid values for both oils, the increase being higher for mixture of coconut oil and soybean oil. The results of such mixing is then tested in bacteria to determine their effectiveness in killing the bacteria. The best ozonation condition is in an increase of 386,85% acid value, peroxide value about 102,91 meq/kg oil, and decrease in iodine number up to 21%. The result showed that under these conditions, ozonized oil has an antiseptic effect against Staphylococcus aureus. The final results of this study are expected to be a new innovation in the healing of skin wounds caused by burns as an anti-inflammatory that is effective, safe, and environmentally friendly.

Experimental Study on Compression/Absorption High-Temperature Hybrid Heat Pump with Natural Refrigerant Mixture

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji Young; Park, Seong Ryong; Baik, Young Jin; Chang, Ki Chang; Ra, Ho Sang; Kim, Min Sung [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Kim, Yong Chan [Korea University, Seoul (Korea, Republic of)

2011-12-15

This research concerns the development of a compression/absorption high-temperature hybrid heat pump that uses a natural refrigerant mixture. Heat pumps based on the compression/absorption cycle offer various advantages over conventional heat pumps based on the vapor compression cycle, such as large temperature glide, temperature lift, flexible operating range, and capacity control. In this study, a lab-scale prototype hybrid heat pump was constructed with a two-stage compressor, absorber, desorber, desuperheater, solution heat exchanger, solution pump, liquid/vapor separator, and rectifier as the main components. The hybrid heat pump system operated at 10-kW-class heating capacity producing hot water whose temperature was more than 90 .deg. C when the heat source and sink temperatures were 50 .deg. C. Experiments with various NH{sub 3}/H{sub 2}O mass fractions and compressor/pump circulation ratios were performed on the system. From the study, the system performance was optimized at a specific NH{sub 3} concentration.

Rheology of petrolatum-paraffin oil mixtures : Applications to analogue modelling of geological processes

NARCIS (Netherlands)

Duarte, João C.; Schellart, Wouter P.; Cruden, Alexander R.

2014-01-01

Paraffins have been widely used in analogue modelling of geological processes. Petrolatum and paraffin oil are commonly used to lubricate model boundaries and to simulate weak layers. In this paper, we present rheological tests of petrolatum, paraffin oil and several homogeneous mixtures of the two.

Energy performance of supermarket refrigeration and air conditioning integrated systems working with natural refrigerants

International Nuclear Information System (INIS)

Cecchinato, Luca; Corradi, Marco; Minetto, Silvia

2012-01-01

The current trends in commercial refrigeration aim at reducing the synthetic refrigerant charge, either by minimising the internal volume of the circuit or by utilising natural refrigerants, and at energy saving. The energy efficiency of supermarkets can be improved by optimising components design, recovering thermal and refrigerating energy, adopting innovative technology solutions, integrating the HVAC system with medium temperature and low temperature refrigeration plants and, finally, reducing thermal loads on refrigerated cases. This study aims at investigating the performance of different lay-out and technological solutions where only natural refrigerants are used and at finding the potential for improving energy efficiency over the traditional systems in different climates. In the analysis, chillers and heat pumps working with ammonia or propane, medium temperature systems working with ammonia or propane and carbon dioxide as heat transfer fluid or with carbon dioxide as the refrigerant and low temperature systems working with carbon dioxide are considered and benchmarked with a state-of-the-art HFCs based plant. The most efficient investigated solution enables an annual energy saving higher than 15% with respect to the baseline solution for all the considered climates. - Highlights: ► Different natural refrigerants supermarket HVAC and R integrated systems are analysed. ► Some of the proposed solutions offer a significant benefit over the baseline one. ► Up to 18.7% energy saving is achieved in the considered climates. ► The refrigeration unit condensation by the AC chiller offers the poorest results.

Analysis of a combined Rankine-vapour-compression refrigeration cycle

International Nuclear Information System (INIS)

Aphornratana, Satha; Sriveerakul, Thanarath

2010-01-01

This paper describes a theoretical analysis of a heat-powered refrigeration cycle, a combined Rankine-vapour-compression refrigeration cycle. This refrigeration cycle combines an Organic Rankine Cycle and a vapour-compression cycle. The cycle can be powered by low grade thermal energy as low as 60 deg. C and can produce cooling temperature as low as -10 deg. C. In the analysis, two combined Rankine-vapour-compression refrigeration cycles were investigated: the system with R22 and the system with R134a. Calculated COP values between 0.1 and 0.6 of both the systems were found.

Development of a youth elixir; La mise en oeuvre d`un elixir de jouvence

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

This short paper presents a new refrigerant developed by Quiri Refrigeration company in collaboration with Electricite de France (EdF), which can replace the no-longer produced R-12 CFC. This substitute, called `youth elixir` is a mixture of HCFCs and has similar physical characteristics, is compatible with the R-12 and can be used in a similar pressure range. Its use requires to modify the existing installation but with a reasonable cost. (J.S.)

Effects of Gelatin-Based Edible Films Enriched with Laurel Essential Oil on the Quality of Rainbow Trout (Oncorhynchus mykiss) Fillets During Refrigerated Storage

OpenAIRE

Tuba Baygar; Taçnur Baygar; Hatice Hasanhocaoglu; Cansu Metin; Yunus Alparslan

2014-01-01

The effects of gelatin films enriched with laurel leaf essential oil on the quality of rainbow trout (Oncorhynchus mykiss) during refrigerated storage at (4±1) °C were examined over a period of 26 days. Fish fillets were wrapped with 8 % gelatin films containing 0, 0.1 and 1 % (by volume per mass) of laurel essential oil and vacuum packaged. Sensory (raw and cooked fish), microbiological (total viable counts, psychrotrophic bacteria counts, Enterobacteriaceae and lactic acid bacteria) and ...

Evaporating heat transfer of R22 and R410A in horizontal smooth and microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Man-Hoe; Shin, Joeng-Seob [Korea Advanced Institute of Science and Technology, Daejeon (Korea). Department of Mechanical Engineering

2005-09-01

An experimental investigation of evaporating heat transfer in 9.52 mm O.D. horizontal copper tubes was conducted. The refrigerants tested were R22 and the near-azeotropic mixture, R410A. The test rig had a straight, horizontal test section with an active length of 0.92 m and was heated by the heat transfer fluid (hot water) circulated in a surrounding annulus. Constant heat flux of 11.0 kW/m{sup 2} was maintained and refrigerant quality varied from 0.2 to 0.8.. The results were reported for evaporation at 15 {sup o}C in a 0.92 m long test section for 30-60 kg/h mass flow rate. The local and average heat transfer coefficients for seven microfin tubes were presented compared to those for a smooth tube. The average evaporation heat transfer coefficients of R22 and R410A for the microfin tubes were 1.86-3.27 and 1.64-2.99 times higher than those for the smooth tube, respectively. When compared to R22 at the same test conditions, the evaporating heat transfer coefficients for R410A were 97-129% of R22. (author)

Exhaust of plant oil fuelled cogeneration unit drives a two-stage refrigerating absorber; Abgas aus Pflanzenoel-BHKW treibt zweistufige Absorptionskaeltemaschine an

Energy Technology Data Exchange (ETDEWEB)

Schmid, W.

2008-05-15

Skating rinks are expensive to operate. In view of exploding energy prices, energetic optimisation is economically favourable even in more recent buildings. In the Hacker-Pschorr-Arena building at Bad Toelz, which was commissioned in 2004, the space HVAC system was modernized. A plant oil fuelled cogeneration unit and an exhaust-driven two-stage refrigerating absorber were installed. (orig.)

Catalytic Partial Oxidation of Biomass/Oil Mixture

Czech Academy of Sciences Publication Activity Database

Veselý, Václav; Hanika, Jiří; Tukač, V.; Lederer, J.; Kovač, D.

2013-01-01

Roč. 7, č. 10 (2013), s. 1940-1945 ISSN 1934-8983 R&D Projects: GA TA ČR TE01020080; GA MPO 2A-2TP1/024 Institutional support: RVO:67985858 Keywords : hydrocarbon oil * biomass * catalytic partial oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.davidpublishing.com/journals_info.asp?jId=1718#

Protective Activity of the Mixtures of Pine Oil and Copper Hydroxide against Bacterial Spot and Anthracnose on Red Pepper

Directory of Open Access Journals (Sweden)

Jae-Woo Soh

2014-09-01

Full Text Available This research was performed to examine the protective activities of the mixtures of pine oil and copper hydroxide against bacterial spot and anthracnose on pepper plants. As for bacterial spot, the treatment of pine oil alone displayed high disease incidence (59.6% and low protective effect (28.9%. In comparison, the treatments of mixtures and copper hydroxide alone showed protective activities of 66.8-76.1%. The mixture of pine oil and copper hydroxide (4:1 suppressed the most effectively bacterial spot on pepper. On the other hand, the mixture of pine oil and copper hydroxide (4:1 also showed the strongest protective effect against pepper anthracnose among the 4 treatments tested; its disease incidence and disease control value were 49.8% and 41.7%, respectively. The other treatments showed low protective activities with control values of 7.4-17.1%. These results suggested that the mixture of pine oil and copper hydroxide (4:1 can be used for the environmental-friendly disease control of bacterial spot and anthracnose on pepper.

Study of mixtures based on hydrocarbons used in ORC (Organic Rankine Cycle) for engine waste heat recovery

International Nuclear Information System (INIS)

Shu, Gequn; Gao, Yuanyuan; Tian, Hua; Wei, Haiqiao; Liang, Xingyu

2014-01-01

For high temperature ORC (Organic Rankine Cycle) used in engine waste heat recovery, it's very critical to select a high temperature working fluid. HCs (Hydrocarbons) usually have excellent cycle performance, but the flammability limits their practical application. Considering that some retardants can be used to suppress flammability, the paper presents an application of mixtures based on hydrocarbons blending with refrigerant retardants to engine waste heat ORC. Three pure hydrocarbons (cyclopentane, cyclohexane, benzene) and two retardants (R11, R123) are selected for combination. Thermal efficiency and exergy loss are selected as the main objective functions. Based on thermodynamic model, the effects of retardants mass fraction, evaporation temperature and IHE (internal heat exchanger) are investigated. Results show that zeotropic mixtures do have higher thermal efficiency and lower exergy loss than pure fluids, at a certain mixture ratio. There exists the OMR (optimal mixture ratio) for different mixtures, and it changes with the evaporation temperature. When adding IHE to system, cycle performance could be obviously improved, and for benzene/R11 (0.7/0.3), the efficiency growth is about 7.12%∼9.72%. Using it, the maximum thermal efficiency of the system can achieve 16.7%, and minimum exergy loss is only 30.76 kW. - Highlights: • A theoretical analysis of Organic Rankine Cycle for engine exhaust heat recovery is proposed. • Mixtures based on hydrocarbons as working fluids have been suggested. • Effects of the IHE (internal heat exchanger) on ORC system are investigated. • OMR (Optimal mixture ratio) changes with the evaporation temperature. • Using the system, maximum thermal efficiency can achieve 16.7%

Investigation of waste heat recovery of binary geothermal plants using single component refrigerants

Science.gov (United States)

Unverdi, M.

2017-08-01

In this study, the availability of waste heat in a power generating capacity of 47.4 MW in Germencik Geothermal Power Plant has been investigated via binary geothermal power plant. Refrigerant fluids of 7 different single components such as R-134a, R-152a, R-227ea, R-236fa, R-600, R-143m and R-161 have been selected. The binary cycle has been modeled using the waste heat equaling to mass flow rate of 100 kg/s geothermal fluid. While the inlet temperature of the geothermal fluid into the counter flow heat exchanger has been accepted as 110°C, the outlet temperature has been accepted as 70°C. The inlet conditions have been determined for the refrigerants to be used in the binary cycle. Finally, the mass flow rate of refrigerant fluid and of cooling water and pump power consumption and power generated in the turbine have been calculated for each inlet condition of the refrigerant. Additionally, in the binary cycle, energy and exergy efficiencies have been calculated for 7 refrigerants in the availability of waste heat. In the binary geothermal cycle, it has been found out that the highest exergy destruction for all refrigerants occurs in the heat exchanger. And the highest and lowest first and second law efficiencies has been obtained for R-600 and R-161 refrigerants, respectively.

Thermochemical recycling of mixture of scrap tyres and waste lubricating oil into high caloric value products

International Nuclear Information System (INIS)

Abdul-Raouf, Manar E.; Maysour, Nermine E.; Abdul-Azim, Abdul-Azim A.; Amin, Mahasen S.

2010-01-01

Scrap tyres and used lubricating oils represent together growing environmental problem because they are not biodegradable and their components cannot readily be recovered. In the present investigation, the thermochemical recycling of mixture of old tyres with waste lubricating oil by pyrolysis and the value of the products obtained have been studied. First, thermobalance experiments were carried out, studying the influence of the following variables: temperature, type of catalyst and catalyst concentration on the pyrolysis reaction of a mixture of 1/1 wt./wt. oil/tyre ratio. These thermobalance results were thoroughly investigated to study the effect of the main process variables on yields of derived products: oils, gases and solid residue.

Commissioning and Operational Experience with 1 kW Class Helium Refrigerator/Liquefier for SST-1

Science.gov (United States)

Dhard, C. P.; Sarkar, B.; Misra, Ruchi; Sahu, A. K.; Tanna, V. L.; Tank, J.; Panchal, P.; Patel, J. C.; Phadke, G. D.; Saxena, Y. C.

2004-06-01

The helium refrigerator/liquefier (R/L) for the Steady State Super conducting Tokamak (SST-1) has been developed with very stringent specifications for the different operational modes. The total refrigeration capacity is 650 W at 4.5 K and liquefaction capacity of 200 l/h. A cold circulation pump is used for the forced flow cooling of 300 g/s supercritical helium (SHe) for the magnet system (SCMS). The R/L has been designed also to absorb a 200 W transient heat load of the SCMS. The plant consists of a compressor station, oil removal system, on-line purifier, Main Control Dewar (MCD) with associated heat exchangers, cold circulation pump and warm gas management system. An Integrated Flow Control and Distribution System (IFDCS) has been designed, fabricated and installed for distribution of SHe in the toroidal and poloidal field coils as well as liquid helium for cooling of 10 pairs of current leads. A SCADA based control system has been designed using PLC for R/L as well as IFDCS. The R/L has been commissioned and required parameters were achieved confirming to the process. All the test results and commissioning experiences are discussed in this paper.

New class of microminiature Joule — Thomson refrigerator and vacuum package

Science.gov (United States)

Paugh, Robert L.

1990-12-01

Progress is reported on the development of a two-stage, fast cooldown Joule — Thomson refrigerator using nitrogen gas and a nitrogen — hydrocarbon gas mixture as the refrigerants. The refrigerator incorporates a microminiature Venturi pump to reduce the pressure of the exhaust of the main boiler to bring the operating temperature of the cold stage to < 70 K in as little as 10 s. The vacuum package for the refrigerator contains no organic materials and is designed to provide a ten year shelf life. Special glass strengthening techniques are being used to achieve cooler survival of acceleration tests of up to 100 000g.

Optimization of Surfactant Mixtures and Their Interfacial Behavior for Advanced Oil Recovery

Energy Technology Data Exchange (ETDEWEB)

Somasundaran, Prof. P.

2001-02-27

The goal of this report is to develop improved extraction processes to mobilize and produce the oil left untapped using conventional techniques. Current chemical schemes for recovering the residual oil have been in general less than satisfactory. High cost of the processes as well as significant loss of chemicals by adsorption on reservoir materials and precipitation has limited the utility of chemical-flooding operations. There is a need to develop cost-effective, improved reagent schemes to increase recovery from domestic oil reservoirs. The goal of the report was to develop and evaluate novel mixtures of surfactants for improved oil recovery.

Contribution to the heat transfer analysis of substitute refrigerants in evaporator tubes with smooth or enhanced tube surfaces

Energy Technology Data Exchange (ETDEWEB)

Kattan, N

1997-12-31

The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requests a good knowledge of heat transfer properties of substitute fluids. A new test facility has been built at the Laboratory for Industrial Energy Systems (LENI) to contribute to this international effort. It consists of two sets of concentric tubes allowing either annular or inside tube convective boiling with a counter current water flow heating to be studied. A new data base including heat transfer coefficients and pressure drop measurements for four new refrigerants (R123, R134A, R402A and R404A) and three older refrigerants (R11, R12 and R502) has been collected. Flow boiling measurements covered a broad range of mass velocities, vapor qualities and heat fluxes. Some of the tests included plain tubes and others enhanced surface tubes (microfilms from Wieland) in horizontal and vertical orientations. An improved Wilson plot technique, that covers both the transition and turbulent flow regimes of the water flowing in the annular channel for the inside tube boiling tests, is proposed to overcome the severe limitations of conventional Wilson plots, to improve accuracy and to facilitate data processing. Mean flow boiling heat transfer coefficients were measured for R12 and R134A evaporating inside a horizontal plain tube and for R11 and R123 evaporating inside a horizontal plain tube. Local flow boiling heat transfer coefficients were measured for : R134A, R123, R404A and R502 evaporating inside a horizontal plain tube, for R134A and R123 evaporating inside a horizontal microfin tube and for R134 evaporating inside a vertical microfin tube. In addition microfin heat transfer augmentation relative to plain tube test data was investigated. The measured heat transfer coefficients were compared to different existing inside tube flow boiling correlations. (author) figs., tabs., refs.

40 CFR Appendix E to Subpart B of... - The Standard for Automotive Refrigerant Recycling Equipment Intended for Use With Both CFC-12 and...

Science.gov (United States)

2010-07-01

... Refrigerant Recycling Equipment Intended for Use With Both CFC-12 and HFC-134a E Appendix E to Subpart B of... Appendix E to Subpart B of Part 82—The Standard for Automotive Refrigerant Recycling Equipment Intended for... Intended for Use With Both CFC-12 and HFC-134a Foreword The purpose of this standard is to establish...

Recent investigations on refrigerants for magnetic refrigerators

International Nuclear Information System (INIS)

Hashimoto, T.

1986-01-01

In development of the magnetic refrigerator, an important problem is selection of magnetic materials as refrigerants. The main purpose of the present paper is to discuss the magnetic and thermal properties necessary for these refrigerants and to report recent investigations. Magnetic refrigerants can be expediently divided into two groups, one for the Carnottype magnetic refrigerator below 20 K and the other for the Ericsson-type refrigerator. The required physical properties of refrigerants in each type of the magnetic refrigerator are first discussed. And then, the results of recent investigations on the magnetic, thermal and magnetocaloric characters of several promising magnetic refrigerants are shown. Finally, a brief prospect of the magnetic refrigerants and refrigerators is given

Boiling Heat Transfer to Halogenated Hydrocarbon Refrigerants

Science.gov (United States)

Yoshida, Suguru; Fujita, Yasunobu

The current state of knowledge on heat transfer to boiling refrigerants (halogenated hydrocarbons) in a pool and flowing inside a horizontal tube is reviewed with an emphasis on information relevant to the design of refrigerant evaporators, and some recommendations are made for future research. The review covers two-phase flow pattern, heat transfer characteristics, correlation of heat transfer coefficient, influence of oil, heat transfer augmentation, boiling from tube-bundle, influence of return bend, burnout heat flux, film boiling, dryout and post-dryout heat transfer.

Technology Application of Environmental Friendly Refrigeration (Green Refrigeration) on Cold Storage for Fishery Industry

Science.gov (United States)

Rasta, IM; Susila, IDM; Subagia, IWA

2018-01-01

The application of refrigeration technology to postharvest fishery products is an very important. Moreover, Indonesia is a tropical region with relatively high temperatures. Fish storage age can be prolonged with a decrease in temperature. Frozen fish can even be stored for several months. Fish freezing means preparing fish for storage in low-temperature cold storage. The working fluid used in cold storage to cool low-temperature chambers and throw heat into high-temperature environments is refrigerant. So far refrigerant used in cold storage is Hydrochloroflourocarbons (HCFC) that is R-22. Chlor is a gas that causes ODP (Ozone Depleting Potential), while Flour is a gas that causes GWP (Global Warming Potential). Government policy began in 2015 to implement Hydrochloroflourocarbons Phase-Out Management Plan. Hydrocarbon (HC) is an alternative substitute for R-22. HC-22 (propane ≥ 99.5%) has several advantages, among others: environmentally friendly, indicated by a zero ODP value, and GWP = 3 (negligible), thermophysical property and good heat transfer characteristics, vapor phase density Which is low, and good solubility with mineral lubricants. The use of HC-22 in cold storage is less than R-22. From the analysis results obtained, cold storage system using HC-22 has better performance and energy consumption is more efficient than the R-22.

Research and Development Roadmap For Next-Generation Low-Global Warming Potential Refrigerants

Energy Technology Data Exchange (ETDEWEB)

none,

2011-07-01

The Department of Energy commissioned this roadmap to establish a set of high-priority research and development (R&D) activities that will accelerate the transition to low-GWP refrigerants across the entire heating, ventilation, air-conditioning and refrigeration (HVAC&R) industry. The schedule of R&D activities occurs within an accelerated five-year timeframe, and covers several prominent equipment types. The roadmap is organized around four primary objectives to: assess and mitigate safety risks, characterize refrigerant properties, understand efficiency and environmental tradeoffs, and support new refrigerant and equipment development.

Experimental investigations on a diesel engine operated with fuel blends derived from a mixture of Pakistani waste tyre oil and waste soybean oil biodiesel.

Science.gov (United States)

Qasim, Muhammad; Ansari, Tariq Mahmood; Hussain, Mazhar

2017-10-18

The waste tyre and waste cooking oils have a great potential to be used as alternative fuels for diesel engines. The aim of this study was to convert light fractions of pyrolysis oil derived from Pakistani waste vehicle tyres and waste soybean oil methyl esters into valuable fuel and to reduce waste disposal-associated environmental problems. In this study, the waste tyre pyrolysis liquid (light fraction) was collected from commercial tyre pyrolysis plant and biodiesel was prepared from waste soybean oil. The fuel blends (FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50) were prepared from a 30:70 mixture of waste tyre pyrolysis liquid and waste soybean oil methyl esters with different proportions of mineral diesel. The mixture was named as the fuel mixture of waste oils (FMWO). FT-IR analysis of the fuel mixture was carried out using ALPHA FT-IR spectrometer. Experimental investigations on a diesel engine were carried out with various FMWO blends. It was observed that the engine fuel consumption was marginally increased and brake thermal efficiency was marginally decreased with FMWO fuel blends. FMWO10 has shown lowest NOx emissions among all the fuel blends tested. In addition, HC, CO and smoke emissions were noticeably decreased by 3.1-15.6%, 16.5-33.2%, and 1.8-4.5%, respectively, in comparison to diesel fuel, thereby qualifying the blends to be used as alternative fuel for diesel engines.

Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Rooftop Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Bargach, Youssef [Navigant Consulting Inc., Burlington, MA (United States)

2016-09-01

The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for Low-Global Warming Potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants relative to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in packaged or Rooftop Unit (RTU) air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerants selection process, the test procedures, and the final results.

Helium refrigeration system for BNL colliding beam accelerator

International Nuclear Information System (INIS)

Brown, D.P.; Farah, Y.; Gibbs, R.J.; Schlafke, A.P.; Schneider, W.J.; Sondericker, J.H.; Wu, K.C.

1983-01-01

A Helium Refrigeration System which will supply the cooling required for the Colliding Beam Accelerator at Brookhaven National Laboratory is under construction. Testing of the compressor system is scheduled for late 1983 and will be followed by refrigerator acceptance tests in 1984. The refrigerator has a design capacity of 24.8 kW at a temperature level near 4K while simultaneously producing 55 kW for heat shield loads at 55K. When completed, the helium refrigerator will be the world's largest. Twenty-five oil-injected screw compressors with an installed total of 23,250 horsepower will supply the gas required. One of the unique features of the cycle is the application of three centrifugal compressors used at liquid helium temperature to produce the low temperatures (2.5K) and high flow rates (4154 g/s) required for this service

Quantitative analysis of properties of petroleum mixtures by near infrared spectroscopy; Analise quantitativa de propriedades de misturas de petroleos via espectrofotometria no infravermelho proximo

Energy Technology Data Exchange (ETDEWEB)

Santos, Leila M.; Silva, Elisangela B.; Fortuny, Montserrat; Dariva, Claudio; Santos, Alexandre F. [Universidade Tiradentes (UNIT), Aracaju, SE (Brazil). Instituto de Tecnologia e Pesquisa (ITP); Araujo, Augusto M. [Siemens Brazil, Rio de Janeiro, RJ (Brazil); Coutinho, Raquel C.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2008-07-01

An experimental study is carried out aiming to develop a method of quantitative analysis of properties of petroleum mixtures, such as water and asphaltene contents, heavy oil concentration and viscosity based on the use of a NIR spectrophotometer. A strategy of generation of crude oil mixtures with known properties was developed to help calibrating the NIR spectrophotometer. Petroleum mixtures involving 2 or 3 oils under known ratios were prepared based on a set of different light and heavy Brazilian crude oil samples. Moreover, experimental data of 5 binary mixtures were also assembled into a data set named multi-compound. Results indicated that excellent calibration models can be obtained for binary mixtures with correlation coefficient (R{sup 2}) greater than 99% for water and asphaltene contents, viscosity and heavy oil concentration. For ternary systems, excellent correlations (R{sup 2}>99%) can be attained for asphaltene and heavy oil contents. Finally for the multi-compound data set, the asphaltene content was the only property that resulted in R{sup 2}>99%, which demonstrates the adequacy of the NIR technique for assessing this property. (author)

Analysis of Refrigeration Cycle Performance with an Ejector

Directory of Open Access Journals (Sweden)

Wani J. R.

2016-01-01

Full Text Available A conventional refrigeration cycle uses expansion device between the condenser and the evaporator which has losses during the expansion process. A refrigeration cycle with ejector is a promising modification to improve the performance of conventional refrigeration cycle. The ejector is used to recover some of the available work so that the compressor suction pressure increases. To investigate the enhancement a model with R134a refrigerant was developed. To solve the set of equations and simulate the cycle performance a subroutine was written on engineering equation solver (EES environment. At specific conditions, the refrigerant properties are obtained from EES. At the design conditions the ejector refrigeration cycle achieved 5.141 COP compared to 4.609 COP of the conventional refrigeration cycle. This means that ejector refrigeration cycle offers better COP with 10.35% improvement compared to conventional refrigeration cycle. Parametric analysis of ejector refrigeration cycle indicated that COP was influenced significantly by evaporator and condenser temperatures, entrainment ratio and diffuser efficiency.

Applicability of ASST-A helium refrigeration system for JLab End Station Refrigerator

Science.gov (United States)

Hasan, N.; Knudsen, P.; Ganni, V.

2017-12-01

The MØLLER experiment at Jefferson Lab (JLab) is a high power (5 kW) liquid hydrogen target scheduled to be operational in the 12 GeV-era. At present, cryogenic loads and targets at three of JLab’s four experimental halls are supported by the End Station Refrigerator (ESR) - a CTI/Helix 1.5 kW 4.5 K refrigerator. It is not capable of supporting the high power target load and a capacity upgrade of the ESR cryogenic system is essential. The ASST-A helium refrigeration system is a 4 kW 4.5 K refrigerator. It was designed and used for the Superconducting Super Collider Lab (SSCL) magnet string test and later obtained by JLab after the cancellation of that project. The modified ASST-A refrigeration system, which will be called ESR-II along with a support flow from JLab’s Central Helium Liquefier (CHL) is considered as an option for the End Station Refrigerator capacity upgrade. The applicability of this system for ESR-II under varying load conditions is investigated. The present paper outlines the findings of this process study.

Influence of oil on flow condensation heat transfer of R410A inside 4.18 mm and 1.6 mm inner diameter horizontal smooth tubes

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu.; Peng, Hao [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

2010-01-15

The influence of oil on condensation heat transfer of R410A inside 4.18 mm and 1.6 mm inner diameter horizontal smooth tubes is investigated experimentally. The experimental condensing temperature is 40 C, and nominal oil concentration range is from 0% to 5%. The test results indicate that the presence of oil deteriorates the heat transfer, and the deterioration effect becomes obvious with the increase of oil concentration. At oil concentration of 5%, the heat transfer coefficient decreases by maximum 24.9% and 28.5% for 4.18 mm and 1.6 mm tubes, respectively. A new correlation for heat transfer coefficients of R410A-oil mixture flow condensation inside smooth tubes is proposed, which agrees with all the experimental data within a deviation of -30% {proportional_to} +20%. (author)

Thermochemical recycling of mixture of scrap tyres and waste lubricating oil into high caloric value products

Energy Technology Data Exchange (ETDEWEB)

Abdul-Raouf, Manar E.; Maysour, Nermine E.; Abdul-Azim, Abdul-Azim A. [Egyptian Petroleum Research Institute, Nasr City, Cairo (Egypt); Amin, Mahasen S. [Faculty of Science, Benha University, Benha (Egypt)

2010-06-15

Scrap tyres and used lubricating oils represent together growing environmental problem because they are not biodegradable and their components cannot readily be recovered. In the present investigation, the thermochemical recycling of mixture of old tyres with waste lubricating oil by pyrolysis and the value of the products obtained have been studied. First, thermobalance experiments were carried out, studying the influence of the following variables: temperature, type of catalyst and catalyst concentration on the pyrolysis reaction of a mixture of 1/1 wt./wt. oil/tyre ratio. These thermobalance results were thoroughly investigated to study the effect of the main process variables on yields of derived products: oils, gases and solid residue. (author)

Parametric analysis and optimization for a combined power and refrigeration cycle

International Nuclear Information System (INIS)

Wang Jiangfeng; Dai Yiping; Gao Lin

2008-01-01

A combined power and refrigeration cycle is proposed, which combines the Rankine cycle and the absorption refrigeration cycle. This combined cycle uses a binary ammonia-water mixture as the working fluid and produces both power output and refrigeration output simultaneously with only one heat source. A parametric analysis is conducted to evaluate the effects of thermodynamic parameters on the performance of the combined cycle. It is shown that heat source temperature, environment temperature, refrigeration temperature, turbine inlet pressure, turbine inlet temperature, and basic solution ammonia concentration have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. A parameter optimization is achieved by means of genetic algorithm to reach the maximum exergy efficiency. The optimized exergy efficiency is 43.06% under the given condition

Compatibility of refrigerants and lubricants with elastomers

Energy Technology Data Exchange (ETDEWEB)

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

1993-01-01

The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

Performance evaluation of an ejector subcooled vapor-compression refrigeration cycle

International Nuclear Information System (INIS)

Xing, Meibo; Yan, Gang; Yu, Jianlin

2015-01-01

Highlights: • An ejector subcooled vapor-compression refrigeration cycle is proposed. • The performance of the cycle with ejector subcooling is evaluated theoretically. • Increase in refrigeration capacity can be achieved by the ejector subcooled cycle. • The new cycle exhibits higher COP compared to the basic single-stage cycle. • Performance of the new cycle depends on the operation pressures of the ejector. - Abstract: In this study, a novel vapor-compression refrigeration cycle with mechanical subcooling using an ejector is proposed to improve the performance of a conventional single-stage vapor-compression refrigeration cycle. In the theoretical study, a mathematical model is developed to predict the performance of the cycle by using R404A and R290, and then compared with that of the conventional refrigeration cycle. The simulation results show that the performance of the ejector subcooled cycle is better than that of the conventional cycle. When the evaporator temperature ranges from −40 to −10 °C and the condenser temperature is 45 °C, the novel cycle displays volumetric refrigeration capacity improvements of 11.7% with R404A and 7.2% with R290. And the novel cycle achieves COP improvements of 9.5% with R404A and 7.0% with R290. In addition, the improvement of the COP and cooling capacity of this novel cycle largely depends on the operation pressures of the ejector. The potential practical advantages offered by the cycle may be worth further attention in future studies

Flammability Indices for Refrigerants

Science.gov (United States)

Kataoka, Osami

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

On subcooler design for integrated two-temperature supermarket refrigeration system

Energy Technology Data Exchange (ETDEWEB)

Yang, Liang [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Zhang, Chun-Lu [College of Mechanical Engineering, Tongji University, No. 4800, Cao An Highway, Shanghai 201804 (China)

2011-01-15

The energy saving opportunity of supermarket refrigeration systems using subcooler between the medium-temperature (MT) refrigeration system and the low-temperature (LT) refrigeration system has been identified in the previous work. This paper presents a model-based comprehensive analysis on the subcooler design. The optimal subcooling control is discussed as well. With optimal subcooler size and subcooling control, the maximum energy savings of integrated two-temperature supermarket refrigeration system using R404A or R134a as working fluid can achieve 27% or 20%, respectively. The load ratio of MT to LT system and the operating conditions have considerable impact on the energy savings. (author)

Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Kassuga, Theo [Navigant Consulting Inc., Burlington, MA (United States)

2015-10-01

The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

Selective Production of 9R-Hydroxy-10E,12Z,15Z-Octadecatrienoic Acid from α-Linolenic Acid in Perilla Seed Oil Hydrolyzate by a Lipoxygenase from Nostoc Sp. SAG 25.82.

Science.gov (United States)

Kim, Kyoung-Rok; An, Jung-Ung; Lee, Seon-Hwa; Oh, Deok-Kun

2015-01-01

Hydroxy fatty acids (HFAs) derived from omega-3 polyunsaturated fatty acids have been known as versatile bioactive molecules. However, its practical production from omega-3 or omega-3 rich oil has not been well established. In the present study, the stereo-selective enzymatic production of 9R-hydroxy-10E,12Z,15Z-octadecatrienoic acid (9R-HOTE) from α-linolenic acid (ALA) in perilla seed oil (PO) hydrolyzate was achieved using purified recombinant 9R-lipoxygenase (9R-LOX) from Nostoc sp. SAG 25.82. The specific activity of the enzyme followed the order linoleic acid (LA) > ALA > γ-linolenic acid (GLA). A total of 75% fatty acids (ALA and LA) were used as a substrate for 9R-LOX from commercial PO by hydrolysis of Candida rugosa lipase. The optimal reaction conditions for the production of 9R-HOTE from ALA using 9R-LOX were pH 8.5, 15°C, 5% (v/v) acetone, 0.2% (w/v) Tween 80, 40 g/L ALA, and 1 g/L enzyme. Under these conditions, 9R-LOX produced 37.6 g/L 9R-HOTE from 40 g/L ALA for 1 h, with a conversion yield of 94% and a productivity of 37.6 g/L/h; and the enzyme produced 34 g/L 9R-HOTE from 40 g/L ALA in PO hydrolyzate for 1 h, with a conversion yields of 85% and a productivity of 34 g/L/h. The enzyme also converted 9R-hydroxy-10E,12Z-octadecadienoic acid (9R-HODE) from 40 g/L LA for 1.0 h, with a conversion yield of 95% and a productivity of 38.4 g/L. This is the highest productivity of HFA from both ALA and ALA-rich vegetable oil using LOX ever reported. Therefore, our result suggests an efficient method for the production of 9R-HFAs from LA and ALA in vegetable oil using recombinant LOX in biotechnology.

Purification of radioactive waste oil by a supercritical fluid

International Nuclear Information System (INIS)

Yoo, Jaeryong; Sung, Jinhyun; Park, Kwangheon; Kim, Hongdoo; Kim, Hakwon; Lim, Taeyoon; Yim, Sanghak; Yoon, Weonseob

2006-01-01

The radioactive waste oil from the nuclear industry is potentially hazardous due to its possibility to contaminate soil and underwater. Pollutants in waste oil are generally radioactive heavy metals or organo-metals. Radioactive waste oils are highly viscous fluids that are similar to used-motor oils. Several processes have been developed to regenerated used motor oil, such as acid clay treatment, chemical addition, vacuum distillation, thermal cracking and hydrofinishing. However, these technologies are difficult to apply to separating radioactive nuclides from radioactive waste oils. In recent years, our laboratory developed a membrane method for the regeneration of used motor oils. We applied supercritical Co2 (scCO2) as a viscosity reducing additive to waste oils at a lower process temperature in order to improve membrane permeability and thus the energy saving. However, the membrane cannot filter the contaminants in radioactive waste oil that are not particles, such as radioactive ions in impurity water in the oil. In this paper, we suggest a method extracting clean oil from the radioactive waste oil rather than filtering by a supercritical fluid. We selected R22, a refrigerant, as a solvent for extraction. R22 has a mild critical point - 96.1 .deg. and 49.9bar. Regeneration of waste oils by extracting clean oil using a supercritical fluid such as R22 is easy to handle and reduce secondary wastes. In this paper, we examine the feasibility of R22 in extracting clean oil from radioactive waste oils

Boiling of multicomponent working fluids used in refrigeration and cryogenic systems

Science.gov (United States)

Mogorychny, V. I.; Dolzhikov, A. S.

2017-11-01

Working fluids based on mixtures are widely used in cryogenic and refrigeration engineering. One of the main elements of low-temperature units is a recuperative heat exchanger where the return flow cools the direct (cold regeneration is carrying out) resulting in continuous boiling and condensation of the multicomponent working fluid in the channels. The temperature difference between the inlet and outlet of the heat exchanger can be more than 100K, which leads to a strong change in thermophysical properties along its length. In addition, the fraction of the liquid and vapor phases in the flow varies very much, which affects the observed flow regimes in the heat exchanger channels. At the moment there are not so many experimental data and analytical correlations that would allow to estimate the heat transfer coefficient during the flow of a two-phase mixture flow at low temperatures. The work is devoted to the study of the boiling process of multicomponent working fluids used in refrigeration and cryogenic engineering. The description of the method of determination of heat transfer coefficient during boiling of mixtures in horizontal heated channel is given as well as the design of the experimental stand allowing to make such measurements. This stand is designed on the basis of a refrigeration unit operating on the Joule-Thomson throttle cycle and makes it possible to measure the heat transfer coefficient with a good accuracy. Also, the calculated values of the heat transfer coefficient, obtained with the use of various correlations, are compared with the existing experimental data. Knowing of the heat transfer coefficient will be very useful in the design of heat exchangers for low-temperature units operating on a mixture refrigerant.

Viscosity and density study for characterization of oil mixtures; Estudo da viscosidade e densidade para caracterizacao das misturas de petroleo

Energy Technology Data Exchange (ETDEWEB)

Santos, Michelle I.; Azevedo, Vildomar S.; Jacinto, Tulio Wagner B. [Aurizonia Petroleo S.A, Natal, RN (Brazil); Vieira, Mariane; Vidal, Rosangela Regia Lima; Garcia, Rosangela Balaban [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2008-07-01

The oil can be defined as a mixture of hydrocarbons and sulphur, nitrogen and oxygenated organic derivatives at lower amount. There is a practical difficulty of analytical determination of the oil composition, mainly due to the large quantity of medium and heavy oil fractions. For heavier fractions, it is necessary to infer the composition of the cut from properties that can be readily obtained in the laboratory, such as refraction index, density and viscosity. The analysis of oil composition and its fractions is important information on various aspects (IOB et al., 1996): determining the operating conditions of refining, selection of suitable catalysts and mixing operations ('blending'), the economic evaluation of mixtures and analysis of environmental impact due to emissions. The first study on characterization of fractions of the oil was reported by Hill and Coats (1928), who set an empirical relationship between the density and Saybolt viscosity named viscosity-density constant (VGC). The statement was obtained from the analysis of the density with the oil viscosity changes. Physical properties such as density, boiling point and viscosity can be used to classify the oil. The aim of this work was to classify oil fractions based on viscosity-density constant, using mixtures of oils with different APIs. The results showed that there is an optimum composition for each mixture, and the addition of more oil of medium classification does not lead to potential commercial oil. (author)

Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation.

Science.gov (United States)

Li, Jian; Zhao, Zhihong; Li, Dianming; Tian, Haifeng; Zha, Fei; Feng, Hua; Guo, Lin

2017-09-21

Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.

Refrigeration and process engineering: contributions to a better environment; Contributions du genie frigorifique et du genie des procedes pour un meilleur environnement

Energy Technology Data Exchange (ETDEWEB)

Bonjour, J.

2004-05-15

In order to reach a better environment, two groups of methods can be considered: substituting polluting by clean (or at least with a lower impact) operations or developing pollution treatment solutions. This document first presents various researches in Refrigeration aiming to limit the environmental impact of some activities in this field. For instance, researches on boiling heat transfer -and specifically on the mechanisms governing this phenomenon- are developed. The motivation of such studies lies in the enhancement of evaporators. The effect of the presence of oil or of the choice of zeotropic mixtures on refrigerating machines performances is then highlighted. Lastly, a new method for the optimization (minimization) of the energy consumption of water-cooled ammonia compressors is proposed. Process Engineering provides solutions for the treatment of some air pollutants (e.g. Volatile Organic Compounds or carbon dioxide), among which some use the phenomenon of adsorption, and allow the pollutant separation, capture, concentration and possibly recovery. A new TSA (Temperature Swing Adsorption) process with indirect heating and cooling is developed for performing these operations. This TSA process can be enhanced if combined with other processes such as condensation. The analysis methods typical of Energy Engineering (mainly Refrigeration and Air Conditioning) are shown to be an appreciable help for the optimization of the overall air treatment system. This is the incentive for suggesting the use of a new tool, namely a psychrometric-like chart for nitrogen-toluene mixtures in the presence of an activated carbon adsorbent. (author)

Thermoeconomic optimization of subcooled and superheated vapor compression refrigeration cycle

International Nuclear Information System (INIS)

Selbas, Resat; Kizilkan, Onder; Sencan, Arzu

2006-01-01

An exergy-based thermoeconomic optimization application is applied to a subcooled and superheated vapor compression refrigeration system. The advantage of using the exergy method of thermoeconomic optimization is that various elements of the system-i.e., condenser, evaporator, subcooling and superheating heat exchangers-can be optimized on their own. The application consists of determining the optimum heat exchanger areas with the corresponding optimum subcooling and superheating temperatures. A cost function is specified for the optimum conditions. All calculations are made for three refrigerants: R22, R134a, and R407c. Thermodynamic properties of refrigerants are formulated using the Artificial Neural Network methodology

Operation characteristic and performance comparison of organic Rankine cycle (ORC) for low-grade waste heat using R245fa, R123 and their mixtures

International Nuclear Information System (INIS)

Feng, Yong-qiang; Hung, Tzu-Chen; He, Ya-Ling; Wang, Qian; Wang, Shuang; Li, Bing-xi; Lin, Jaw-Ren; Zhang, Wenping

2017-01-01

Highlights: • Experimental comparison using R123, R245fa and their mixtures has been investigated. • The basic operation parameters and the detailed operation characteristics of pure and mixture working fluids are addressed. • The mixture owns a relatively higher pump power consumption, 10–50% higher than that of R245fa and 2–47% higher than that of R123. • The highest system generating efficiency of 4.53% is obtained by 0.67R245fa/0.33R123. - Abstract: The operation characteristic and performance comparison of low-grade organic Rankine cycle (ORC) using R245fa, R123 and their mixtures have been investigated. The heat source temperature is set to be 120 °C, while the mass flow rate is controlled by adjusting the pump frequency. The basic operation parameters are first examined, while the detailed operation characteristics of pure and mixture working fluids are addressed. The system overall performance, including thermal efficiency and system generating efficiency, for pure and mixture working fluids are explored. The experimental results show that the mixtures own a relatively higher pump power consumption and enhancing the pump performance is also significant for ORC application. Whether the mixtures exhibit better thermodynamic performance than the pure working fluids depend on the operation parameters and mass fraction of mixtures. 0.67R245fa/0.33R123 owns the highest maximum net electricity output of 1.67 kW, 4.38% higher than that of R245fa and 63.73% higher than that of R123. Compared to the pure working fluids, the mixture working fluids own a better thermodynamic performance and a moderate economic performance.

Thermoeconomic Optimization of Cascade Refrigeration System Using Mixed Carbon Dioxide and Hydrocarbons at Low Temperature Circuit

Directory of Open Access Journals (Sweden)

Nasruddin Nasruddin

2016-12-01

Full Text Available Many applications and industrial processes require very low cooling temperature, such as cold storage in the biomedical field, requiring temperature below -80 °C. However,single-cycle refrigeration systems can only achieve the effective cooling temperature of -40 °C and, also, the performance of the cycle will decrease drastically for cooling temperatures lower than -35°C. Currently, most of cascade refrigeration systems use refrigerants that have ozone depletion potential (ODP and global warming potential (GWP, therefore, in this study, a cascade system is simulated using a mixture of environmentally friendly refrigerants, namely, carbon dioxide and a hydrocarbon (propane, ethane or ethylene as the refrigerant of the low temperature circuit. A thermodynamic analysis is performed to determine the optimal composition of the mixture of carbon dioxide and hydrocarbons in the scope of certain operating parameters. In addition, an economic analysis was also performed to determine the annual cost to be incurred from the cascade refrigeration system. The multi-objective/thermoeconomic optimization points out optimal operating parameter values of the system, to addressing both exergy efficiency and its relation to the costs to be incurred.

Effect of temperature on thermoacoustic properties of olive oil in alcohol mixtures

International Nuclear Information System (INIS)

Shriwas, R S; Chimankar, O P; Tabhane, P V; Dange, S P; Tembhurkar, Y D

2012-01-01

The ultrasonic studies in liquids are great use in understanding the nature and strength of molecular interactions. Recently ultrasonic is the rapidly growing field research, which has been used in the food industry for both analysis and modification of food products. This paper presents ultrasonic velocity, density, adiabatic compressibility in olive oil with alcohol at different concentration that has been measured in the temperature range from 283.15K to 298.15K. The Moelwyn-Hughes parameter has been utilised to establish some simple relations between the available volumes, Bayer's non- linearity parameter, internal pressure, van der Waal's constant, Debye temperature etc. a relationship among the isobaric, isothermal and isochoric thermo-acoustical parameter have been studied and analyzed in the case olive oil with alcohol mixture. The present treatments had the distinct advantages of the thermo-acoustic parameters in the particular mixture.

Numerical research on the scroll compressor with refrigeration injection

International Nuclear Information System (INIS)

Wang Baolong; Shi Wenxing; Li Xianting; Yan Qisen

2008-01-01

A general model for a scroll compressor with refrigerant injection is established in this paper. The model can be used to predict the macro performance and inner compression process of the injected scroll compressor. A series of experiments are conducted to validate the accuracy of the model. The results show that the model can precisely predict not only the general performance of the compressor but also the inner compression with or without refrigerant injection. Based on the thermodynamic model and the test bench, the injection process of the scroll compressor has been investigated and the thermodynamic essence is revealed. It is found that the refrigerant injection process can be considered as a continual parameter-varying 'adiabatic throttling + isobaric mixture' time-varying process

Effect of vegetable oils on fatty acid composition and cholesterol content of chicken frankfurters

Science.gov (United States)

Belichovska, D.; Pejkovski, Z.; Belichovska, K.; Uzunoska, Z.; Silovska-Nikolova, A.

2017-09-01

To study the effect of pork adipose tissue substitution with vegetable oils in chicken frankfurters, six frankfurter formulations were produced: control; with pork backfat; with olive oil; with rapeseed oil; with sunflower oil; with palm oil, and; with a mixture of 12% rapeseed oil and 8% palm oil. Fatty acid composition and cholesterol content and some oxides thereof were determined in the final products. The use of vegetable oils resulted in improvement of the fatty acid composition and nutritional of frankfurters. Frankfurters with vegetable oils contained significantly less cholesterol and some of its oxides, compared to the frankfurters with pork fat. The formulation with palm oil had the least favourable fatty acid composition. The use of 12% rapeseed oil improved the ratio of fatty acids in frankfurters with a mixture of rapeseed and palm oils. Complete pork fat replacement with vegetable oils in chicken frankfurter production is technologically possible. The mixture of 12% rapeseed oil and 8% palm oil is a good alternative to pork fat from health aspects. Further research is needed to find the most appropriate mixture of vegetable oils, which will produce frankfurters with good sensory characteristics, a more desirable fatty acid ratio and high nutritional value.

Experimental study on a resorption system for power and refrigeration cogeneration

International Nuclear Information System (INIS)

Jiang, L.; Wang, L.W.; Liu, C.Z.; Wang, R.Z.

2016-01-01

Energy conversion technologies, especially for power generation and refrigeration technologies driven by the low temperature heat, are gathering the momentum recently. This paper presents a novel resorption system for electricity and refrigeration cogeneraion. Compared with adsorption refrigeration system, resorption refrigeration is characterized as safety and simple structure since there is no ammonia liquid in the system. The cogeneration system is mainly composed of three HTS (high temperature salt) unit beds; three LTS (low temperature salts) unit beds, one expander, three ammonia valves, two oil valves, four water valves and connection pipes. Chemical working pair of MnCl 2 –CaCl 2 –NH 3 is selected. Since scroll expander is suitable for small type power generation system, it is chosen for expansion process. 4.8 kg MnCl 2 and 3.9 kg CaCl 2 impregnated in expanded natural graphite treated with sulfuric acid (ENG-TSA) are filled in the cogeneration system. Experimental results show that maximum cooling power 2.98 kW is able to be obtained while maximum shaft power is about 253 W with 82.3 W average value. The cogeneration system can be utilized for the heat source temperature lower than 170 °C. Total energy efficiency increases from 0.293 to 0.417 then decreases to 0.407 while exergy efficiency increases from 0.12 to 0.16. - Highlights: • A resorption system for power and refrigeration cogeneration is established and investigated. • ENG-TSA as the additive improves the heat and mass performance of composite adsorbent. • The highest shaft power and refrigeration power are 253 W and 2.98 kW, respectively. • Total energy efficiency of the system increases from 0.293 to 0.417 then decreases to 0.407.

46 CFR 154.1735 - Methyl acetylene-propadiene mixture.

Science.gov (United States)

2010-10-01

... relieve into the compressor suction line. (4) An alarm that sounds in the cargo control station and in the... mixture must have a refrigeration system without vapor compression or have a refrigeration system with the following features: (1) A vapor compressor that does not raise the temperature and pressure of the vapor...

Evaporating heat transfer characteristics of R22 and R410A in 9.52 mm O.D. smooth and microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, M H; Shin, J S; Lim, B H [Sam Sung Electronics Corporation Limited (Korea, Republic of)

1998-10-01

An experimental investigation of evaporating heat transfer in 9.52 mm horizontal copper tubes was conducted. The refrigerant tested were R22 and near-azeotropic mixture, R410A. The test rig had a straight, horizontal test section with an active length of 0.92 m and was heated by the heat transfer fluid(hot water) circulated in a surrounding annulus. Constant heat flux of 11.0 kW/m{sup 2} was maintained and refrigerant quality varied from 0.2 to 0.8. The results were reported for evaporation at 15 deg. C in a 0.92 m long test section for 30{approx}60 kg/h mass flow rate. The local and average heat transfer coefficients for seven microfin tubes were presented compared to those for a smooth tube. The average evaporation heat transfer coefficients of R22 and R410A for the microfin tubes were 86{approx}227% and 64{approx}199%, respectively, higher than those for the smooth tube. When compared to R22 at the same test conditions, the evaporating heat transfer coefficients for R410A were 97{approx}129% of R22. (author). 23 refs., 9 figs., 4 tabs.

Control of the Tevatron Satellite Refrigeration system

International Nuclear Information System (INIS)

Theilacker, J.; Chapman, L.; Gannon, J.; Hentges, M.; Martin, M.; Rode, C.H.; Zagel, J.

1984-01-01

This chapter describes a computerized control system for 24 satellite refrigerators which cool a six kilometer ring of superconducting magnets. The control system consists of 31 independent microprocessors operating over 400 servo loops, and a central computer system which provides monitoring, alarms, logging and changing of parameters. Topics considered include pressure measurement, flow measurement, temperature measurement, gas analysis, control valves, expansion engine controllers, and control loops. Each refrigerator has 12 active microprocessor based control loops which tune the refrigerator to one of its four operating modes: satellite, liquefier, refrigerator, and stand-by. It is suggested that optimizing the refrigerator control loops and quench recovery scheme will minimize the accelerator down time

Curing kinetics of alkyd/melamine resin mixtures

Directory of Open Access Journals (Sweden)

Jovičić Mirjana C.

2009-01-01

Full Text Available Alkyd resins are the most popular and useful synthetic resins applied as the binder in protective coatings. Frequently they are not used alone but are modified with other synthetic resins in the manufacture of the coatings. An alkyd/melamine resin mixture is the usual composition for the preparation of coating called 'baking enamel' and it is cured through functional groups of resins at high temperatures. In this paper, curing kinetics of alkyd resins based on castor oil and dehydrated castor oil with melamine resin, has been studied by DSC method with programmed heating and in isothermal mode. The results determined from dynamic DSC curves were mathematically transformed using the Ozawa isoconversional method for obtaining the isothermal data. These results, degree of curing versus time, are in good agreement with those determined by the isothermal DSC experiments. By applying the Ozawa method it is possible to calculate the isothermal kinetic parameters for the alkyd/melamine resin mixtures curing using only calorimetric data obtained by dynamic DSC runs. Depending on the alkyd resin type and ratio in mixtures the values of activation energies of curing process of resin mixtures are from 51.3 to 114 kJ mol-1. The rate constant of curing increases with increasing the content of melamine resin in the mixture and with curing temperature. The reaction order varies from 1.12 to 1.37 for alkyd based on dehydrated castor oil/melamine resin mixtures and from 1.74 to 2.03 for mixtures with alkyd based on castor oil. Based on the results obtained, we propose that dehydrated castor oil alkyd/melamine resin mixtures can be used in practice (curing temperatures from 120 to 160°C.

A study of alternative refrigerants for the refrigeration and air conditioning sector in Mauritius

Science.gov (United States)

Dreepaul, R. K.

2017-11-01

The most frequently used refrigerants in the refrigeration and air conditioning (RAC) sector in Mauritius are currently hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC). However, because of their strong influence on global warming and the impact of HCFCs on the ozone layer, refrigerants such as ammonia (NH3), carbon dioxide (CO2) and Hydrocarbons (HC), having minimal impact on the environment, are being considered. So far, HCs have only been safely used in domestic refrigeration. Ammonia has been used mainly for industrial refrigeration whereas CO2 is still under study. In this paper, a comparative study of the various feasible alternatives is presented in a survey that was undertaken with major stake holders in the field. The retrofitting possibility of existing equipment was assessed and safety issues associated with each refrigerant were analysed. The major setback of hydrocarbons as a widely accepted refrigerant is its flammability which was considered as a major safety hazard by the majority of respondents in the survey and the main advantages are the improved equipment coefficient of performance (COP) and better TEWI factor. This resulted in a 12 % drop in energy consumption. Despite the excellent thermodynamic properties of ammonia, its use has mainly been confined to industrial refrigeration due to its toxicity. In Mauritius, the performance of ammonia in air conditioning is being evaluated on a pilot basis. The major setback of carbon dioxide as a refrigerant is the high operating pressure which is considered a safety hazard. The high initial investment cost and the lack of qualified maintenance technician is also an issue. The use of CO2 is mainly being considered in the commercial refrigeration sector.

Improving Asphalt Mixture Performance by Partially Replacing Bitumen with Waste Motor Oil and Elastomer Modifiers

Directory of Open Access Journals (Sweden)

Sara Fernandes

2017-08-01

Full Text Available The environmental concern about waste generation and the gradual decrease of oil reserves has led the way to finding new waste materials that may partially replace the bitumens used in the road paving industry. Used motor oil from vehicles is a waste product that could answer that demand, but it can also drastically reduce the viscosity, increasing the asphalt mixture’s rutting potential. Therefore, polymer modification should be used in order to avoid compromising the required performance of asphalt mixtures when higher amounts of waste motor oil are used. Thus, this study was aimed at assessing the performance of an asphalt binder/mixture obtained by replacing part of a paving grade bitumen (35/50 with 10% waste motor oil and 5% styrene-butadiene-styrene (SBS as an elastomer modifier. A comparison was also made with the results of a previous study using a blend of bio-oil from fast pyrolysis and ground tire rubber modifier as a partial substitute for usual PG64-22 bitumen. The asphalt binders were tested by means of Fourier infrared spectra and dynamic shear rheology, namely by assessing their continuous high-performance grade. Later, the water sensitivity, fatigue cracking resistance, dynamic modulus and rut resistance performance of the resulting asphalt mixtures was evaluated. It was concluded that the new binder studied in this work improves the asphalt mixture’s performance, making it an excellent solution for paving works.

Effects of a mixture of vegetable and essential oils and fatty acid potassium salts on Tetranychus urticae and Phytoseiulus persimilis.

Science.gov (United States)

Tsolakis, H; Ragusa, S

2008-06-01

Laboratory trials were carried out to evaluate the toxicity and the influence of a commercial mixture of vegetal, essential oils, and potassium salts of fatty acids (Acaridoil 13SL) on the population growth rate (r(i)--instantaneous rate of increase) of two mite species, the phytophagous Tetranychus urticae Koch and the predator Phytoseiulus persimilis Athias-Henriot. A residue of 1.3 mg/cm(2) of pesticide solution was harmless for Ph. persimilis eggs, while a moderate mortality of eggs and of larvae from treated eggs of T. urticae, was observed (53.8%). The pesticide also caused a delay in the postembryonic development of the tetranychid. Moreover, 83.4% mortality was reported for treated females tetranychids and only 24.0% for Ph. persimilis females. The pesticide influenced negatively the population growth of T. urticae which showed a very low rate of increase (r(i)=0.07), compared to that obtained in the control (r(i)=0.68). The pesticide did not affect negatively the reproductive potential of Ph. persimilis (r(i)=0.54 and r(i)=0.57 for test and control, respectively). These results suggest a considerable acaricidal activity of potassium salts of fatty acids and caraway oil on T. urticae and a good selectivity on Ph. persimilis.

Rotary magnetic refrigerator for superfluid helium production

International Nuclear Information System (INIS)

Hakuraku, Y.; Ogata, H.

1986-01-01

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%

Stabilization of heavy oil-water emulsions using a bio/chemical emulsifier mixture

Energy Technology Data Exchange (ETDEWEB)

Farahbakhsh, A.; Taghizadeh, M.; Movagharnejad, K. [Chemical Engineering Department, Babol University of Technology, Babol (Iran, Islamic Republic of); Yakhchali, B. [National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of)

2011-11-15

In this study, the viscosity reduction of heavy oil has been investigated through the formation of oil-water emulsion using a bio/chemical emulsifier mixture. Four bioemulsifiers from indigenous Rhodococcus ergthropolis and Bacillus licheniformis strains were used to stabilize a highly-viscous oil-in-water emulsion. The Taguchi method with an L{sub 9} orthogonal array design was used to investigate the effect of various control factors on the formation of the oil/water emulsions. An emulsion with lowest viscosity was formed using ACO4 strain. The substantial stability of the oil-in-water emulsion allows the heavy oil to be transported practically over long distances or remain stationary for a considerable period of time prior to utilization. As the result of Taguchi analysis, the temperature and concentration of the emulsifier had a significant influence on viscosity reduction of the emulsion. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Being everything to anyone: Applicability of thermoacoustic technology in the commercial refrigeration market

Science.gov (United States)

Poese, Matthew E.; Smith, Robert W. M.; Garrett, Steven L.

2005-09-01

This talk will compare electrodynamically driven thermoacoustic refrigeration technology to some common implementations of low-lift vapor-compression technology. A rudimentary explanation of vapor-compression refrigeration will be presented along with some of the implementation problems faced by refrigeration engineers using compressor-based systems. These problems include oil management, compressor slugging, refrigerant leaks and the environmental impact of refrigerants. Recently, the method of evaluating this environmental impact has been codified to include the direct effects of the refrigerants on global warming as well as the so-called ``indirect'' warming impact of the carbon dioxide released during the generation (at the power plant) of the electrical power consumed by the refrigeration equipment. It is issues like these that generate commercial interest in an alternative refrigeration technology. However, the requirements of a candidate technology for adoption in a mature and risk-averse commercial refrigeration industry are as hard to divine as they are to meet. Also mentioned will be the state of other alternative refrigeration technologies like free-piston Stirling, thermoelectric and magnetocaloric as well as progress using vapor compression technology with alternative refrigerants like hydrocarbons and carbon dioxide.

Numerical investigation of boiling heat transfer on hydrocarbon mixture refrigerant in vertical rectangular minichannel

Directory of Open Access Journals (Sweden)

Huixing Li

2016-05-01

Full Text Available In order to investigate the characteristics of boiling heat transfer for hydrocarbon mixture refrigerant in plate-fin heat exchanger which is used in the petrochemical industry field, a model was established on boiling heat transfer in vertical rectangular channel. The simulated results were compared with the experimental data from literature. The results show that the deviation between the simulated results and experimental data is within ±15%. Meanwhile, the characteristic of boiling heat transfer was investigated in vertical rectangular minichannel of plate-fin heat exchanger. The results show that the boiling heat transfer coefficient increases with the increase in quality and mass flux and is slightly impacted by the heat flux. This is because that the main boiling mechanism is forced convective boiling while the contribution of nucleate boiling is slight. The correlation of Liu and Winterton is in good agreement with the simulation results. The deviation between correlation calculations and simulation results is mostly less than ±15%. These results will provide some constructive instructions for the understanding of saturated boiling mechanism in a vertical rectangular minichannel and the prediction of heat transfer performance in plate-fin heat exchanger.

The selective partitioning of the oligomers of polyethoxylated surfactant mixtures between interface and oil and water bulk phases.

Science.gov (United States)

Graciaa, Alain; Andérez, José; Bracho, Carlos; Lachaise, Jean; Salager, Jean-Louis; Tolosa, Laura; Ysambertt, Fredy

2006-11-16

Because their affinities for the oil and water phases vary considerably with the number of ethylene oxide units in their hydrophilic group, the ethoxylated nonionic species occurring in commercial products tend to behave in a non-collective way, with the low ethoxylation oligomers partitioning mostly in the oil phase. This results in a surfactant mixture at the interface which is more hydrophilic than the one which was introduced in the system in the first place. The pseudophase model is used to study the partitioning in Winsor III type systems, and to estimate the deviation of the interfacial mixture composition from the overall one. New results indicate that the selective partitioning into the oil phase increases when the oil phase becomes aromatic, when the total surfactant concentration decreases and when the water-to-oil ratio decreases.

The Safety and Efficacy of a Mixture of Honey, Olive Oil, and Beeswax for the Management of Hemorrhoids and Anal Fissure: A Pilot Study

Directory of Open Access Journals (Sweden)

Noori S. Al-Waili

2006-01-01

Full Text Available We have found that a mixture of honey, olive oil, and beeswax was effective for treatment of diaper dermatitis, psoriasis, eczema, and skin fungal infection. The mixture has antibacterial properties. A prospective pilot study was conducted to evaluate the therapeutic effect of topical application of the mixture on patients with anal fissure or hemorrhoids.Fifteen consecutive patients, 13 males and 2 females, median age 45 years (range: 28–70, who presented with anal fissure (5 patients or first- to third-degree hemorrhoids (4 with first degree, 4 with second degree, and 2 with third degree, were treated with a 12-h application of a natural mixture containing honey, olive oil, and beeswax in ratio of 1:1:1(v/v/v. Bleeding, itching, edema, and erythema were measured using a scoring method: 0 = none, 1 = mild, 2 = moderate, 3 = severe, and 4 = very severe. The pain score was checked using a visual analog scale (minimum = 0, maximum = 10. Efficacy of treatment was assessed by comparing the symptoms' score before and after treatment; at weekly intervals for a maximum of 4 weeks. The patients were observed for evidence of any adverse effect such as appearance of new signs and symptoms, or worsening of the existing symptoms. The honey mixture significantly reduced bleeding and relieved itching in patients with hemorrhoids. Patients with anal fissure showed significant reduction in pain, bleeding, and itching after the treatment. No side effect was reported with use of the mixture. We conclude that a mixture of honey, olive oil, and beeswax is safe and clinically effective in the treatment of hemorrhoids and anal fissure, which paves the way for further randomized double blind studies.

Optimization of Surfactant Mixtures and Their Interfacial Behavior for Advanced Oil Recovery

Energy Technology Data Exchange (ETDEWEB)

Somasundaran, Prof. P.

2002-03-04

The objective of this project was to develop a knowledge base that is helpful for the design of improved processes for mobilizing and producing oil left untapped using conventional techniques. The main goal was to develop and evaluate mixtures of new or modified surfactants for improved oil recovery. In this regard, interfacial properties of novel biodegradable n-alkyl pyrrolidones and sugar-based surfactants have been studied systematically. Emphasis was on designing cost-effective processes compatible with existing conditions and operations in addition to ensuring minimal reagent loss.

Image analysis for composition monitoring. Commercial blends of olive and soybean oil - doi: 10.4025/actascitechnol.v35i2.15216

Directory of Open Access Journals (Sweden)

Jessica Kehrig Fernandes

2013-04-01

Full Text Available Olive oil represents an important component of a healthy and balanced dietary. Due to commercial features, characterization of pure olive oil and commercial mixtures represents an important challenge. Reported techniques can successfully quantify components in concentrations lower than 1%, but may present long delays, too many purification steps or use expensive equipment. Image analysis represents an important characterization technique for food science and technology. By coupling image and UV-VIS spectroscopy analysis, models with linear dependence on parameters were developed and could successfully describe the mixture concentration in the range of 0-100% in mass of olive oil content. A validation sample, containing 25% in mass of olive oil, not used for parameter estimation, was also used for testing the proposed procedure, leading to a prediction of 24.8 ± 0.6. Due to image analysis results,  3-parameter-based models considering only R and G components were developed for olive oil content prediction in mixtures with up to 70% in mass of olive oil, the same test sample was used and its concentration was predicted as 24.5 ± 1.2. These results show that image analysis represents a promising technique for on-line/in-line monitoring of blending process of olive soybean oil for commercial mixtures.  

Co-crystal of (R,R)-1,2-cyclohexanediol with (R,R)-tartaric acid, a key structure in resolution of the ({+-})-trans-diol by supercritical extraction, and the related ternary phase system

Energy Technology Data Exchange (ETDEWEB)

Thorey, Paul [Department of Chemical and Environmental Process Engineering, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Bombicz, Petra [Institute of Structural Chemistry, Chemical Research Center, Hungarian Academy of Science, H-1525 Budapest (Hungary); Szilagyi, Imre Miklos [Material Structure and Modeling Research Group, Hungarian Academy of Sciences, H-1111 Budapest (Hungary); Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Molnar, Peter; Bansaghi, Gyoergy; Szekely, Edit; Simandi, Bela [Department of Chemical and Environmental Process Engineering, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Parkanyi, Laszlo [Institute of Structural Chemistry, Chemical Research Center, Hungarian Academy of Science, H-1525 Budapest (Hungary); Pokol, Gyoergy [Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Madarasz, Janos, E-mail: madarasz@mail.bme.hu [Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, H-1521 Budapest (Hungary)

2010-01-10

A novel co-crystal of trans-(R,R)-1,2-cyclohexanediol and (R,R)-tartaric acid (with 1:1 molar ratio, 1) has been found to be a key crystalline compound in the improved resolution of ({+-})-trans-1,2-cyclohexanediol by supercritical fluid extraction. The molecular and crystal structure of this co-crystal, which crystallizes in orthorhombic crystal system (space group P2{sub 1}2{sub 1}2{sub 1}, a = 6.7033(13) A, b = 7.2643(16), c = 24.863(5), Z = 4), has been solved by single crystal X-ray diffraction (R = 0.064). The packing arrangement consists of two dimensional layers of sandwich-like sheets, where the inner part is constructed by double layers of tartaric acids which hydrophilicity is 'covered' on both upper and bottom side by cyclohexanediols with the hydrophobic cyclohexane rings pointing outward. Thus, a rather complex hydrogen bonding pattern is constructed. The relatively high melting point (133 {sup o}C) observed by both simultaneous TG/DTA and DSC, and the main features of FTIR-spectrum of 1 are explained by the increased stability of this crystal structure. DSC studies on binary mixtures of co-crystal 1 with (R,R)-1,2-cyclohexanediol or (R,R)-tartaric acid, revealed eutectic temperatures of T{sub eu} = 100 or 131 {sup o}C, respectively. Between (S,S)-1,2-cyclohexanediol and (R,R)-tartaric acid a eutectic temperature of T{sub eu} = 85 {sup o}C have also been observed. The phase relations have been confirmed by powder X-ray diffraction, as well.

Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

Science.gov (United States)

Gondrand, C.; Durand, F.; Delcayre, F.; Crispel, S.; Baguer, G. M. Gistau

2014-01-01

Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power.

Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

International Nuclear Information System (INIS)

Gondrand, C.; Durand, F.; Delcayre, F.; Crispel, S.; Baguer, G. M. Gistau

2014-01-01

Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power

Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

Energy Technology Data Exchange (ETDEWEB)

Gondrand, C.; Durand, F.; Delcayre, F.; Crispel, S. [AL-AT, 2 rue de Clémencières, 38360 Sassenage (France); Baguer, G. M. Gistau [CRYOGUY, 44, chemin de la Buisse, 38330 Biviers (France)

2014-01-29

Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power.

Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures

Directory of Open Access Journals (Sweden)

Florian Heberle

2015-03-01

Full Text Available We present a thermo-economic evaluation of binary power plants based on the Organic Rankine Cycle (ORC for geothermal power generation. The focus of this study is to analyse if an efficiency increase by using zeotropic mixtures as working fluid overcompensates additional requirements regarding the major power plant components. The optimization approach is compared to systems with pure media. Based on process simulations, heat exchange equipment is designed and cost estimations are performed. For heat source temperatures between 100 and 180 °C selected zeotropic mixtures lead to an increase in second law efficiency of up to 20.6% compared to pure fluids. Especially for temperatures about 160 °C, mixtures like propane/isobutane, isobutane/isopentane, or R227ea/R245fa show lower electricity generation costs compared to the most efficient pure fluid. In case of a geothermal fluid temperature of 120 °C, R227ea and propane/isobutane are cost-efficient working fluids. The uncertainties regarding fluid properties of zeotropic mixtures, mainly affect the heat exchange surface. However, the influence on the determined economic parameter is marginal. In general, zeotropic mixtures are a promising approach to improve the economics of geothermal ORC systems. Additionally, the use of mixtures increases the spectrum of potential working fluids, which is important in context of present and future legal requirements considering fluorinated refrigerants.

Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [ORNL; Munk, Jeffrey D [ORNL; Shrestha, Som S [ORNL; Linkous, Randall Lee [ORNL; Goetzler, William [Navigant Consulting Inc.; Guernsey, Matt [Navigant Consulting Inc.; Kassuga, Theo [Navigant Consulting Inc.

2015-08-01

The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

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

Energy Technology Data Exchange (ETDEWEB)

Dennis Cartlidge; Hans Schellhase

2003-07-31

This report summarizes a literature review to assess the acidity characteristics of the older mineral oil and newer polyolester (POE) refrigeration systems as well as to evaluate acid measuring techniques used in other non-aqueous systems which may be applicable for refrigeration systems. Failure in the older chlorofluorocarbon/hydrochlorofluorocarbon (CFC/HCFC) / mineral oil systems was primarily due to thermal degradation of the refrigerant which resulted in the formation of hydrochloric and hydrofluoric acids. These are strong mineral acids, which can, over time, severely corrode the system metals and lead to the formation of copper plating on iron surfaces. The oil lubricants used in the older systems were relatively stable and were not prone to hydrolytic degradation due to the low solubility of water in oil. The refrigerants in the newer hydrofluorocarbon (HFC)/POE systems are much more thermally stable than the older CFC/HCFC refrigerants and mineral acid formation is negligible. However, acidity is produced in the new systems by hydrolytic decomposition of the POE lubricants with water to produce the parent organic acids and alcohols used to prepare the POE. The individual acids can therefore vary but they are generally C5 to C9 carboxylic acids. Organic acids are much weaker and far less corrosive to metals than the mineral acids from the older systems but they can, over long time periods, react with metals to form carboxylic metal salts. The salts tend to accumulate in narrow areas such as capillary tubes, particularly if residual hydrocarbon processing chemicals are present in the system, which can lead to plugging. The rate of acid production from POEs varies on a number of factors including chemical structure, moisture levels, temperature, acid concentration and metals. The hydrolysis rate of reaction can be reduced by using driers to reduce the free water concentration and by using scavenging chemicals which react with the system acids. Total acid

Flow, stock, and impact assessment of refrigerants in the Japanese household air conditioner sector.

Science.gov (United States)

Xue, Mianqiang; Kojima, Naoya; Machimura, Takashi; Tokai, Akihiro

2017-05-15

Refrigerants provide society with great benefits while have the potential to cause adverse effects on the environment and human health. The present study estimated time-dependent flows and stocks and assessed the effects of refrigerants (R-22, R-410a, and R-32) in household air conditioners in Japan. It was found that stock of R-22 and R-410a peaked at 49,147t in 2000 and 55,994t in 2017, respectively. The largest flow of R-22 and R-410a to waste phase occurred at 3417t/yr. in 2005 and 4011t/yr. in 2023, respectively. The total global warming potential (GWP) due to refrigerant emissions increased from 3.6kt CO 2 eq. in 1952 to 6999kt CO 2 eq. in 2019, and then decreased to 5314kt CO 2 eq. in 2030. The ozone depletion potential (ODP) peaked at 141t CFC-11 eq. in 2002. When substituting R-410a for R-22, the ODP decreased 50% while the GDP increased 8%. When substituting R-32 for R-410a, there was no effect on the ODP while the GDP decreased 6%. The human health damage due to the global warming effect of refrigerant emission was much higher than that due to the ozone depleting effect. The refrigerant emission in use and waste management phases dominated the human health damage. The dynamic estimation not only allows us to evaluate the performance of past policies but also supports the future sustainable management associated with the health effects of refrigerants. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of natural lipstick formulation based on pitaya (Hylocereus polyrhizus) seed oil using D-optimal mixture experimental design.

Science.gov (United States)

Kamairudin, Norsuhaili; Gani, Siti Salwa Abd; Masoumi, Hamid Reza Fard; Hashim, Puziah

2014-10-16

The D-optimal mixture experimental design was employed to optimize the melting point of natural lipstick based on pitaya (Hylocereus polyrhizus) seed oil. The influence of the main lipstick components-pitaya seed oil (10%-25% w/w), virgin coconut oil (25%-45% w/w), beeswax (5%-25% w/w), candelilla wax (1%-5% w/w) and carnauba wax (1%-5% w/w)-were investigated with respect to the melting point properties of the lipstick formulation. The D-optimal mixture experimental design was applied to optimize the properties of lipstick by focusing on the melting point with respect to the above influencing components. The D-optimal mixture design analysis showed that the variation in the response (melting point) could be depicted as a quadratic function of the main components of the lipstick. The best combination of each significant factor determined by the D-optimal mixture design was established to be pitaya seed oil (25% w/w), virgin coconut oil (37% w/w), beeswax (17% w/w), candelilla wax (2% w/w) and carnauba wax (2% w/w). With respect to these factors, the 46.0 °C melting point property was observed experimentally, similar to the theoretical prediction of 46.5 °C. Carnauba wax is the most influential factor on this response (melting point) with its function being with respect to heat endurance. The quadratic polynomial model sufficiently fit the experimental data.

Optimization of Natural Lipstick Formulation Based on Pitaya (Hylocereus polyrhizus Seed Oil Using D-Optimal Mixture Experimental Design

Directory of Open Access Journals (Sweden)

Norsuhaili Kamairudin

2014-10-01

Full Text Available The D-optimal mixture experimental design was employed to optimize the melting point of natural lipstick based on pitaya (Hylocereus polyrhizus seed oil. The influence of the main lipstick components—pitaya seed oil (10%–25% w/w, virgin coconut oil (25%–45% w/w, beeswax (5%–25% w/w, candelilla wax (1%–5% w/w and carnauba wax (1%–5% w/w—were investigated with respect to the melting point properties of the lipstick formulation. The D-optimal mixture experimental design was applied to optimize the properties of lipstick by focusing on the melting point with respect to the above influencing components. The D-optimal mixture design analysis showed that the variation in the response (melting point could be depicted as a quadratic function of the main components of the lipstick. The best combination of each significant factor determined by the D-optimal mixture design was established to be pitaya seed oil (25% w/w, virgin coconut oil (37% w/w, beeswax (17% w/w, candelilla wax (2% w/w and carnauba wax (2% w/w. With respect to these factors, the 46.0 °C melting point property was observed experimentally, similar to the theoretical prediction of 46.5 °C. Carnauba wax is the most influential factor on this response (melting point with its function being with respect to heat endurance. The quadratic polynomial model sufficiently fit the experimental data.

Performance Optimization of Alternative Lower Global Warming Potential Refrigerants in Mini-Split Room Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Shrestha, Som S [ORNL

2017-01-01

Oak Ridge National laboratory (ORNL) recently conducted extensive laboratory, drop-in investigations for lower Global Warming Potential (GWP) refrigerants to replace R-22 and R-410A. ORNL studied propane, DR-3, ARM-20B, N-20B and R-444B as lower GWP refrigerant replacement for R-22 in a mini-split room air conditioner (RAC) originally designed for R-22; and, R-32, DR-55, ARM-71A, and L41-2, in a mini-split RAC designed for R-410A. We obtained laboratory testing results with very good energy balance and nominal measurement uncertainty. Drop-in studies are not enough to judge the overall performance of the alternative refrigerants since their thermodynamic and transport properties might favor different heat exchanger configurations, e.g. cross-flow, counter flow, etc. This study compares optimized performances of individual refrigerants using a physics-based system model tools. The DOE/ORNL Heat Pump Design Model (HPDM) was used to model the mini-split RACs by inputting detailed heat exchangers geometries, compressor displacement and efficiencies as well as other relevant system components. The RAC models were calibrated against the lab data for each individual refrigerant. The calibrated models were then used to conduct a design optimization for the cooling performance by varying the compressor displacement to match the required capacity, and changing the number of circuits, refrigerant flow direction, tube diameters, air flow rates in the condenser and evaporator at 100% and 50% cooling capacities. This paper compares the optimized performance results for all alternative refrigerants and highlights best candidates for R-22 and R-410A replacement.

Method and refrigerants for replacing existing refrigerants in centrifugal compressors

International Nuclear Information System (INIS)

Kopko, W.L.

1991-01-01

This patent describes a method for replacing an existing refrigerant in a centrifugal compressor. It comprises selecting a desired impeller Mach number for the centrifugal compressor; selecting a base refrigerant constituent; combining at least one additive refrigerant constituent with the base refrigerant constituent to form a replacement refrigerant having at least one physical or chemical property different from the existing refrigerant and substantially providing the desired impeller Mach number in the centrifugal compressor; and replacing the existing refrigerant with the replacement refrigerant

Process optimisation of microwave-assisted extraction of peony ( Paeonia suffruticosa Andr .) seed oil using hexane-ethanol mixture and its characterisation

Science.gov (United States)

Xiaoli Sun; Wengang Li; Jian Li; Yuangang Zu; Chung-Yun Hse; Jiulong Xie; Xiuhua Zhao

2016-01-01

Ethanol and hexane mixture agent microwave-assisted extraction (MAE) method was conducted to extract peony (Paeonia suffruticosa Andr.) seed oil (PSO). The aim of the study was to optimise the extraction for both yield and energy consumption in mixture agent MAE. The highest oil yield (34.49%) and lowest unit energy consumption (14 125.4 J g -1)...

Gelation of Oil Slicks by Amine Carbamates as an Adjunct to U.S. Navy Oil Spill Recovery Operations

Science.gov (United States)

1977-01-14

plan for a field test in Boston Harbor was to be developed and submitted to the EPA, Coast Guard, state and municipal water control authorities. Di ...Residual Special Fuel Oil #6, and similar oils) was found to be a mixture of 40 g. dodecylamine, 25 R. tetradecylamine, and 4.5 g. hexadecylamine In...solution with 100 g. methyl alcohol. By far the best system, however, was a mixture of 70% dehydroabletylamine ("Amine D", as manufactured by Hercules Corp

Oil spill R ampersand D efforts in Sweden

International Nuclear Information System (INIS)

Thorell, D.; Jansson, B.

1992-01-01