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Zeitschriftenartikel zum Thema „PURE REFRIGERANTS“

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Veröffentlicht am 11. September 2023

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1

Hsieh, Shou-Shing, und Chun-Jen Weng. „Nucleate Pool Boiling Heat Transfer Coefficients of Distilled Water (H2O) and R-134a/Oil Mixtures From Rib-Roughened Surfaces“. Journal of Heat Transfer 119, Nr. 1 (01.02.1997): 142–51. http://dx.doi.org/10.1115/1.2824079.

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Measurements of pool-boiling heat transfer coefficients in distilled water and R-134a/oil mixtures with up to 10 percent (by weight) miscible EMKARATE RL refrigeration lubricant oil are extensively studied for a smooth tube and four rib-roughened tubes (rib pitch 39.4 mm, rib height 4 mm, rib width 15 mm, number of rib element 8, rib angle 30 deg–90 deg). Boiling data of pure refrigerants and oil mixtures, as well as the influences of heat flux level on heat transfer coefficient, are presented and discussed. A correlation is developed for predicting the heat transfer coefficient for both pure refrigerants and refrigerant-oil mixtures. Moreover, boiling visualizations were made to broaden our fundamental understanding of the pool boiling heat transfer mechanism for rib roughened surfaces with pure refrigerants and refrigerant-oil mixtures.

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2

Li, Hong. „Study on Alternative Refrigerants for Direct Expansion Solar Assisted Heat Pump System“. Applied Mechanics and Materials 361-363 (August 2013): 267–70. http://dx.doi.org/10.4028/www.scientific.net/amm.361-363.267.

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This paper reports the investigation results of the possibilities for using pure and mixed refrigerants as working fluids to replace R22 for the DX-SAHP systems. Firstly, pure refrigerants are compared in terms of COP, discharge temperature and mass flow rate. Comparison results show that R290 is the most promising alternative to R22. Secondly, two kinds of mixed refrigerants are investigated as well. It indicated that the mixed refrigerant R290/R22 with more R290 performs better than the others in terms of COP. Meanwhile, the mixed refrigerants produce relatively low discharge temperatures and proper mass flow rates can be created due to appropriate mixture in suitable mass proportion. Further investigation indicates that R290 and R290/R22 show better system performance with relatively high superheating temperatures.

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3

Chamra, L. M., und P. J. Mago. „Modelling of evaporation heat transfer of pure refrigerants and refrigerant mixtures in microfin tubes“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 221, Nr. 4 (01.04.2007): 443–47. http://dx.doi.org/10.1243/0954406jmes131.

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A semi-empirical model to predict the evaporation heat transfer of pure refrigerants and refrigerant mixtures flowing inside microfin tubes has been presented. The heat transfer coefficient correlation developed in the new model takes into account the nucleate boiling component and the forced convention component. The model was validated using a set of around 380 experimental data points compiled from published literature. Comparison shows that the model is capable of predicting evaporation heat transfer coefficients for different refrigerants and refrigerant mixtures within 10-25 per cent mean absolute deviation for the data sets.

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4

Wang, Qiang, Zhengyong Huang, Shucheng Ou und Ruiqiang Zhang. „The Energy Storage Properties of Refrigerants (R170, R134a, R143a, and R152a) in Mof-5 Nanoparticles: A Molecular Simulation Approach“. Materials 12, Nr. 21 (31.10.2019): 3577. http://dx.doi.org/10.3390/ma12213577.

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The thermophysical properties of refrigerant can be modified via adding solid materials to it. In this paper, molecular simulations and thermodynamic calculations were employed to investigate the adsorption and energy storage of ethane (R170), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), and 1,1-difluoroethane (R152a) in metal organic framework (MOF)-5 nanoparticles. The results show that the fluorine atom in the refrigerants will strengthen the adsorption of refrigerants in MOF-5. However, the fluorine-free refrigerant, R170, owns larger enthalpy difference of desorption than the other refrigerants with fluorine under high pressure. The thermal energy storage capacity of the refrigerant/MOF-5 mixture is larger than that of the pure refrigerant at low pressure. Also, the negative enhancement of the energy storage property of the mixture is found in some cases when the refrigerant experiences phase transition.

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5

Yan, Fei, Qiang Wang, Shucheng Ou, Ruiqiang Zhang und Guoqiang Wang. „Molecular simulation study for adsorption and thermal energy storage analysis of refrigerants (R170, R161, R152a, and R143a) mixed with UIO-67 nanoparticles“. Modern Physics Letters B 34, Nr. 30 (03.08.2020): 2050334. http://dx.doi.org/10.1142/s0217984920503340.

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Generally, with the help of adding solid materials, the thermophysical behaviors of refrigerant can be modified. In this work, four kinds of organic refrigerants (i.e. ethane R170, 1-fluoroethane R161, 1,1-difluoroethane R152a, and 1,1,1-trifluoroethane R143a) mixed with metal–organic framework UIO-67 nanoparticles are selected as the objects, their thermodynamic energy, adsorption, desorption heat, and energy storage properties are investigated by means of molecular simulations and thermodynamic calculations. The simulation method and calculation details are elaborated. The results illustrate that the relationship between the change of thermodynamic energy and the temperature is linear, and the adsorption of refrigerants in UIO-67 can be reinforced owing to the fluorine atom in the refrigerants. However, R170, the fluorine-free refrigerant, has greater enthalpy variation of desorption than the other three refrigerants containing fluorine atom under some pressures. The thermal energy storage capacity of the refrigerant/UIO-67 mixture is greater than that of the pure refrigerant at low pressure. Meantime, as the refrigerant undergoes phase transition, the weakened improvement of the energy storage property of the refrigerant/UIO-67 mixture is found in some cases. This work can not only enrich the content of researches about metal–organic heat carrier nanofluids (MOHCs), but also provide guidance for the performance improvement and practical application of organic refrigerants.

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6

Saleh, Bahaa, Ayman A. Aly, Mishal Alsehli, Ashraf Elfasakhany und Mohamed M. Bassuoni. „Performance Analysis and Working Fluid Selection for Single and Two Stages Vapor Compression Refrigeration Cycles“. Processes 8, Nr. 9 (20.08.2020): 1017. http://dx.doi.org/10.3390/pr8091017.

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Screening for alternative refrigerants with high energy efficiency and low environmental impacts is one of the highest challenges of the refrigeration sector. This paper investigates the performance and refrigerant screening for single and two stages vapor compression refrigeration cycles. Several pure hydrocarbons, hydrofluorocarbons, hydrofluoroolefins, fluorinated ethers, and binary azeotropic mixtures are proposed as alternative refrigerants to substitute R22 and R134a due to their environmental impacts. The BACKONE equation of state is used to compute the thermodynamic properties of the candidates. The results show that the maximum coefficients of performance (COP) for single and two stage cycles using pure substances are achieved using cyclopentane with values of 4.14 and 4.35, respectively. On the other side, the maximum COP for the two cycles using azeotropic mixtures is accomplished using R134a + RE170 with values of 3.96 and 4.27, respectively. The two-stage cycle presents gain in COP between 5.1% and 19.6% compared with the single-stage cycle based on the used refrigerant. From the obtained results, among all investigated refrigerants, cyclopentane is the most suitable refrigerant for the two cycles from the viewpoint of energy efficiency. However, extra cautions should be taken due to its flammability.

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7

Soujoudi, Ray, und Randall Manteufel. „Thermodynamic performance of ammonia in liquefied natural gas precooling cycle“. Thermal Science, Nr. 00 (2021): 72. http://dx.doi.org/10.2298/tsci201227072s.

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The selection of proper refrigerants for natural gas liquefaction processes play a key role in cycle?s efficiency. Mixed refrigerants have been proven to improve cycle?s exergy efficiency over single pure refrigerant. However, the future of some of these refrigerants with higher global warming potential index (GWPI) are unknown due to the continuous restriction being enforced by the energy and environmental agencies over the past few decades. This study examines the benefits and drawbacks of mixing ammonia, a refrigerant with zero GWPI and a high occupational safety characteristic, with lighter hydrocarbon refrigerants such as methane and ethane as a mixed refrigerant in a natural gas liquefaction?s precooling cycle. Results showed, presence of ammonia in mixed refrigerant not only saved in capital cost due to the smaller footprint of plant and smaller cold box, it also lowers the plants precooling operation expense by reducing the required compression power needed for the precooling cycle up to 16.2%. The results of exergy analyses showed that by reducing the molar concentration of more pollutant refrigerant methane and replacing it with ammonia enhanced the cycle?s efficiency by 4.3% and lowered the heat exchanger total exergy loss up to 47.9 [kW.kgLNG-1].

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Chamra, L. M., P. J. Mago, M.-O. Tan und C.-C. Kung. „Modelling of evaporation and condensation pressure drop in microfin tubes“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 219, Nr. 1 (01.01.2005): 61–70. http://dx.doi.org/10.1243/095440605x8306.

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A semi-empirical model to predict the pressure drop of pure refrigerants and refrigerant mixtures in microfin tubes for both condensation and evaporation is presented. The new pressure-drop model is based on an existing smooth-tube correlation. The model was validated using experimental data compiled from published literature and this showed that the model is capable of predicting pressure drops for different refrigerants and refrigerant mixtures within 10–25 per cent mean absolute deviation. This model can be employed in micro-fin tubes with fin heights from 0.1 to 0.38 mm, helix angles from 0 to 30°, and mass flux ranges up to 600 kg/m2 s.

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9

Morales-Espejel, Guillermo E., Hans H. Wallin, Rudolf Hauleitner und Magnus Arvidsson. „Progress in rolling bearing technology for refrigerant compressors“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, Nr. 16 (21.08.2017): 2948–61. http://dx.doi.org/10.1177/0954406217725772.

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The paper describes the latest technological solutions in rolling bearings (ball and roller) used in refrigerant compressors. First, the numerous tribological challenges faced by rolling contacts in a lubricant environment made of oil and refrigerant mixture are discussed. It is followed by a description of the even tougher conditions derived by the replacement of the more chemically stable pre-Montreal and pre-Kyoto Protocol refrigerants by the new generation of more environmental friendly refrigerants. In these conditions, rolling bearings are expected to suffer from surface distress and sometimes corrosion fatigue. Thus, attempts to model these conditions by using advanced tribological models are described. Finally, descriptions of different solutions in rolling bearings in refrigerant compressors facing challenges in lubrication and bearing life are described, all the way from traditional oil–refrigerant mixture lubrication up to the latest innovation related to oil-free lubrication, namely the pure refrigerant lubrication.

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10

Hasheer, Shaik Mohammad, und Kolla Srinivas. „Performance Comparison of a Low GWP Refrigerants as Alternatives to R134a in a Refrigerator with and without Liquid-Suction Heat Exchanger“. Materials Science Forum 969 (August 2019): 343–48. http://dx.doi.org/10.4028/www.scientific.net/msf.969.343.

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The usage of refrigerators and air conditioners are more prevalent in a domestic environment now-a-days. Improving the efficiency of these devices can be considered as an important step to reduce their energy consumption. Currently, in India, most refrigerators work with HFC-134a as a refrigerant. The GWP value of HFC-134a is around 1430.Therefore, there is a greater demand to replace HFCs with low GWP refrigerants. In this document, the comparison of the performance of a refrigerator without fluid intake heat exchanger (LSHX) with low GWP refrigerants and the results are compared with HFC-134a performed. The low GWP refrigerants used in the test are: hydrocarbon-propane (R290) and isobutane (R600a), the pure hydrocarbons are HFC-134a and HFC-152a and the refrigerants are hydrofluoroolefins 1234yf and 1234ze (E). All have been tested without making changes in the system. The entire examination was carried out in the same system under the same working conditions.

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11

Gessner, Tobias R., und Jader R. Barbosa. „Modeling absorption of pure refrigerants and refrigerant mixtures in lubricant oil“. International Journal of Refrigeration 29, Nr. 5 (August 2006): 773–80. http://dx.doi.org/10.1016/j.ijrefrig.2005.12.001.

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12

Gupta, Abhishek S., Kartik S. Bhosale, Mohd Aman Ahmed, Zuheb Rawoot und Prof Dhanashree Ware. „Design and Development of R32a and HFO-1234yf Refrigeration blend in Air conditioning System“. International Journal for Research in Applied Science and Engineering Technology 11, Nr. 4 (30.04.2023): 3162–66. http://dx.doi.org/10.22214/ijraset.2023.50537.

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Abstract: Refrigeration and air-conditioning systems become an integral part of modern society. Electricity-driven vapour compression systems have been dominating the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry. The working fluids of these systems often contribute to the environmental issues in the forms of direct and indirection emissions. Pure refrigerants are often limited inmeeting criteria such as efficiency, flammability, toxicity, and compatibility. Meanwhile, refrigerant mixtures offer flexibilities to tune these criteria, This paper will review the status worldwide on technical and policy search for next-generation refrigerants with both low Global Warming Potential (LGWP) and low Life Cycle Climate Performance (LCCP) with particular focus on R410A replacement for unitary A/C & H/P. R32 and the HFO blends offer potential solutionsbut all involve tradeoffs among Global Warming Potential (GWP), efficiency, safety, and cost. With the U.S. mandating new higher regional efficiency standard taking effect January 2015, there is even more pressure in finding a LowGWP refrigerant solution that is affordable and can sustain efficiency and reduce charge requirement. This paper focuses more on R32 as the available data for HFO blends is limited. And Mixing of both R32a and HFO-1234yf in Ac To Study the performance two different next generation refrigerants R32 and Hfo-1234yf.To determine most promising refrigerant blend for air conditioning system test observe, anaylize and compare result obtained with conventional refrigerant. To determine impact of R32 and HFO-1234yf refrigerant as a replacement of R410A

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13

Kim, M. S., W. J. Mulroy und D. A. Didion. „Performance Evaluation of Two Azeotropic Refrigerant Mixtures of HFC-134a With R-290 (Propane) and R-600a (Isobutane)“. Journal of Energy Resources Technology 116, Nr. 2 (01.06.1994): 148–54. http://dx.doi.org/10.1115/1.2906020.

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The reduction in chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) production and the scheduled phase-out of these ozone-depleting refrigerants require the development and determination of environmentally safe refrigerants for use in heat pumps, water chillers, air conditioners, and refrigerators. This paper presents a performance evaluation of a generic heat pump with two azeotropic refrigerant mixtures of HFC-134a (1,1,1,2-tetrafluoroethane) with R-290 (propane) and R-600a (isobutane); R-290/134a (45/55 by mass percentage) and R-134a/600a (80/20 by mass percentage). The performance characteristics of the azeotropes were compared with pure CFC-12, HFC-134a, HCFC-22, and R-290 at the high temperature cooling and heating conditions including those using liquid-line/suction-line heat exchange. The coefficient of performance of R-290/134a is lower than that of HCFC-22 and R-290, and R-134a/600a shows higher coefficient of performance than CFC-12 and HFC-134a. The capacity for R-290/134a is higher than that for HCFC-22 and R-290, and R-134a/600a exhibits higher system capacity than CFC-12 and HFC-134a. Experimental results show that the discharge temperatures of the studied azeotropic mixtures are lower than those of the pure refrigerants, CFC-12 and HCFC-22.

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Wongwises, Somchai, und Worachet Pirompak. „Flow characteristics of pure refrigerants and refrigerant mixtures in adiabatic capillary tubes“. Applied Thermal Engineering 21, Nr. 8 (Juni 2001): 845–61. http://dx.doi.org/10.1016/s1359-4311(00)00090-9.

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15

Lu, Xingbin, Jinping Liu und Xiongwen Xu. „Contact angle measurements of pure refrigerants“. International Journal of Heat and Mass Transfer 102 (November 2016): 877–83. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2016.06.099.

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16

Hamad, Ahmed J. „Experimental Investigation of Vapor Compression Refrigeration System Performance Using Nano-Refrigerant“. Wasit Journal of Engineering Sciences 2, Nr. 2 (02.10.2014): 12–27. http://dx.doi.org/10.31185/ejuow.vol2.iss2.26.

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Experimental investigation of vapor compression refrigeration system performance using Nano-refrigerant is presented in this work. Nano-refrigerant was prepared in current work by mixing 50 nanometers diameter of copper oxide CuO nanoparticles with Polyolester lubrication oil and added to the compressor of the refrigeration system to be mixed with pure refrigerant R-134a during its circulation through refrigeration system. Three concentrations (0.1%, 0.25%, and 0.4%) of CuO-R134 a Nano-refrigerant are used to study the performance of the refrigeration system test rig and to investigate the effect of using Nano-refrigerant as a working fluid compared with pure refrigerant R-134a. The results showed that, the increasing in concentration of CuO nanoparticles in the Nano-refrigerant will significantly enhance the performance of the refrigeration system, as adding nanoparticles will increase the thermal conductivity, heat transfer and improve the thermo-physical properties of Nano-refrigerant. Investigation of performance parameters for refrigeration system using Nano-refrigerant with 0.4% concentration compared with that for pure refrigerant R-134a shows that, Nano-refrigerant has reflect higher performance in range of 10% and 1.5% increase in COP and refrigeration effect respectively and 7% reduction in power consumption for refrigeration system. It can be concluded that, Nano-refrigerants can be efficiently and economically feasible to be used in the vapor compression refrigeration systems.

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Sulaimon, Shodiya, Azhar Abdul Aziz, Nasution Henry und Amer Nordin Darus. „Investigation of Various Mixtures of HC290/HC600 Refrigerants in Adiabatic Capillary Tube Used in Split-Type Air-Conditioner“. Applied Mechanics and Materials 388 (August 2013): 71–75. http://dx.doi.org/10.4028/www.scientific.net/amm.388.71.

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: According to Montreal Protocol, HCFC22 (hydro chlorofluorocarbon), a commonly used refrigerant in domestic refrigeration and air-conditioner, must be phased out owing to its environmental problem. Several natural substances including ammonia, carbon dioxide, water and hydrocarbon (HC) such as propane (HC290) and butane (HC600) and their mixtures have immerged as close substitute. Literature showed that pure HC refrigerant may not be suitable enough because of the difference in operating pressure and volumetric cooling capacity when compared with HCFC22. The main objective of this study is to theoretically investigate different ratios of HC refrigerants HC290/HC600 mixtures flowing through adiabatic capillary tube using homogenous model. In this study, the percentage by volume of HC290 was varied from 30 to 40 % in a step of 5%. The pressure at the two extreme ends and temperature along the capillary tube, using HCFC22 refrigerant, which was used as benchmark, was experimentally determined in the air-conditioning (AC) system. Comparing the model results with the experimental data showed that HC refrigerants HC290/HC600 in ratio 35%/65% gave 2.95% minimum error and thus it can be used as a substitute to HCFC22 in the split-type AC system.

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Saleh, B., und M. Wendland. „Screening of pure fluids as alternative refrigerants“. International Journal of Refrigeration 29, Nr. 2 (März 2006): 260–69. http://dx.doi.org/10.1016/j.ijrefrig.2005.05.009.

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19

Zheng, Dayu, Shengnan Feng, Liping Gao und Menglu Li. „Molecular dynamics simulation of non-azeotropic refrigerants separation in auto-cascading refrigeration“. E3S Web of Conferences 118 (2019): 01006. http://dx.doi.org/10.1051/e3sconf/201911801006.

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The core problem of auto-cascading refrigeration is the separation of non-azeotropic refrigerants. The separation effect of mixed refrigerant directly determines the refrigeration effect of auto-cascading refrigeration system and the value of COP. The microscopic molecular dynamics simulation method is applied to the refrigeration system, and the properties of the pure substance and the mixed substance are simulated from the microscopic aspects to study the law of molecular condensation cooling, and the separation rate is simulated to obtain a more optimized scheme.

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Belghazi, M., A. Bontemps und C. Marvillet. „Condensation Heat Transfer on Enhanced Surface Tubes: Experimental Results and Predictive Theory“. Journal of Heat Transfer 124, Nr. 4 (16.07.2002): 754–61. http://dx.doi.org/10.1115/1.1459728.

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Condensation heat transfer in a bundle of horizontal enhanced surface copper tubes (Gewa C+ tubes) has been experimentally investigated, and a comparison with trapezoidal shaped fin tubes with several fin spacing has been made. These tubes have a specific surface three-dimensional geometry (notched fins) and the fluids used are either pure refrigerant (HFC134a) or binary mixtures of refrigerants (HFC23/HFC134a). For the pure fluid and a Gewa C+ single tube, the results were analyzed with a specifically developed model, taking into account both gravity and surface tension effects. For the bundle and for a pure fluid, the inundation of the lowest tubes has a strong effect on the Gewa C+ tube performances contrary to the finned tubes. For the mixture, the heat transfer coefficient decreases dramatically for the Gewa C+ tube.

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PASEK, ARI D., und ARYADI SUWONO. „APPLICATION OF HYDROCARBON BASED REFRIGERANTS FOR AIR CONDITIONING IN INDONESIA“. International Journal of Air-Conditioning and Refrigeration 19, Nr. 04 (Dezember 2011): 303–9. http://dx.doi.org/10.1142/s201013251100065x.

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Electrical energy consumption in air conditioning systems reaches 60% to 70% of the total electric energy consumption in buildings. Therefore, saving electrical energy consumption in air conditioning systems would have a significant impact on the national electrical energy consumption. Currently, the air conditioning sectors were having a dilemma on finding the alternative substitutes for CFC and HCFC refrigerants which are proven to cause destruction of the ozone layer and contribute to the effects of global warming. This paper will discuss the problems faced by an Article 5 country similar to Indonesia in phasing-out HCFC especially in air conditioning and refrigeration sectors. This paper will also discuss the possibility to use hydrocarbon-based refrigerants, which have zero ozone depletion potential (ODP) and low global warming potential (GWP), in air conditioning sectors. Some results of field applications of this refrigerant will be reported, and in general it can be concluded that the air conditioning retrofitted with hydrocarbon refrigerant consumes 10%–20% less electrical energy. Mixture of R-290 and R-134a was also investigated. R-134a is used to reduce the flammability of R-290 and to make the saturation pressure close to R-22. The results show that at composition of 0.6 R-290/0.4 R-134a mole fractions, the mixture behave as an azeotrope refrigerant mixture and can be used for R-22 replacement. At this composition, lower flammability limit (LEL) is 3693%, which is higher than pure R-290. Hence, the refrigerant mixture can be classified as less flammable A2 class refrigerant. The performance test shows that the refrigerant mixture can be used as a drop-in refrigerant in the R-22 machine. The measurement of refrigeration capacity and compressor input work at the same chilled water temperature shows that the calculated COP of the refrigerant mixture is better than R-22's but lower than R-290's.

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Vidhyarthi, Neeraj Kumar, Sandipan Deb, Sameer Sheshrao Gajghate, Sagnik Pal, Dipak Chandra Das, Ajoy Kumar Das und Bidyut Baran Saha. „A Comprehensive Assessment of Two-Phase Flow Boiling Heat Transfer in Micro-Fin Tubes Using Pure and Blended Eco-Friendly Refrigerants“. Energies 16, Nr. 4 (16.02.2023): 1951. http://dx.doi.org/10.3390/en16041951.

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This review study examines flow boiling heat transfer in micro-fin tubes using mixed and pure refrigerants with zero ozone-depleting potential (ODP) and minimal global warming potential (GWP). This investigation focuses on the extraordinary relationship between heat transfer coefficients (HTCs) and vapor quality. Since the introduction of micro-fin heat exchanger tubes over 30 years ago, refrigerant-based cooling has improved significantly. Air conditioning and refrigeration companies are replacing widely used refrigerants, with substantial global warming impacts. When space, weight, or efficiency are limited, micro-fin heat exchangers with improved dependability are preferred. This review article discusses flow boiling concepts. The researchers used several refrigerants under different testing conditions and with varying micro-fin tube parameters. Micro-fin tubes are promising for improved heat transfer techniques. This tube increases the heat transfer area, fluid disturbance, flow speed, and direction owing to centrifugal force and HTC. As the focus shifts to improving heat transfer, pressure drop, mean vapor quality, and practical devices, this subject will grow more intriguing. A radical shift will reduce equipment size for certain traditional heat transfer systems and bring new products using micro-scale technologies. This suggested review effort helps comprehend saturation flow boiling through micro-fin tubes and find the right correlation for a given application. This domain’s challenges and future relevance are also discussed.

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Feroskhan, M., T. Venugopal, Naif Mana Almakayeel, T. M. Yunus Khan, Saleh Alghamdi, Ali Saeed Almuflih und N. Gobinath. „Fundamentals, Thermophysical Properties, and Heat Transfer Characteristics of Nanorefrigerants: A Review“. Journal of Nanomaterials 2022 (06.06.2022): 1–18. http://dx.doi.org/10.1155/2022/8618152.

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Cooling applications that utilize latent heat property of fluids involve large heat transfer and throw more space for energy conservative research studies. Heating ventilation air-conditioning and refrigeration systems, which have now grown as an integral part in human life, circulate refrigerants and necessitate developments to become energy-efficient. The heat removal characteristics of the fluids in such large capacity systems can be enhanced using nanoparticles seeded in to them. Being smaller in size, the nanoparticles possess larger effective surface area and believed to help in expediting the conduction rate of heat from the refrigerants in the HVAC-R systems. Spectrums of nanoparticles are studied for their heat transfer behavior either in pure refrigerants or with refrigerant/oil mixtures. Suspension of the particles in the refrigerants for a prolonged time is found to be critical and must be validated prior to its implementation in the systems. Seeding of nanoparticles exclusively in a phase change fluid inside the refrigeration systems is reported to be of challenging. Additionally, to harvest the benefits of nanoscale particles, literature proposes the usage of surfactants which may lead to complex situation in a vapor compression refrigeration system. In the present work, all the relevant study details specifically on synthesis and characterization, thermophysical properties, and heat transfer characteristics about the nanorefrigerants are presented.

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Vali, Shaik Sharmas, Talanki Puttaranga Setty und Ashok Babu. „Analytical computation of thermodynamic performance parameters of actual vapour compression refrigeration system with R22, R32, R134a, R152a, R290 and R1270“. MATEC Web of Conferences 144 (2018): 04009. http://dx.doi.org/10.1051/matecconf/201814404009.

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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.

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Al-Zahrani, Ahmed. „Energy and Exergy Analysis on Zeotropic Refrigerants R-455A and R-463A as Alternatives for R-744 in Automotive Air-Conditioning System (AACs)“. Processes 11, Nr. 7 (17.07.2023): 2127. http://dx.doi.org/10.3390/pr11072127.

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The popularity of vehicles and the increased time spent in cars with air conditioning systems has led to regulations in many countries that require the use of environmentally friendly refrigerants with minimal global warming and zero ozone depletion potential (GWP and ODP). Cars need high-performance, eco-friendly air conditioning systems to reduce their impact on the environment, lower fuel consumption, and decrease carbon emissions. The aim of the current work was to propose CO2-based blend zeotropic refrigerants, R-455A (R-744/32/1234yf) and R-463A (R-744/32/125/1234yf/134a), to improve the thermodynamic performance of pure CO2 refrigerants. The thermodynamic energy and exergy analysis and system optimization of an AAC system for the new zeotropic refrigerant blends compared to carbon dioxide (R-744), using Aspen HYSYS software, were investigated. The influence of cooler/condenser pressure, average evaporator temperature, cooler/condenser outlet temperature, and refrigerant flow rate on the cycles’ COP and exergy efficiency were conducted and are presented. The results showed that, at the same operating condition parameters, the cycle COP improved by 57.6 and 76.5% when using R455A and R463A instated of R744, respectively, with the advantage of reducing leakage problems due to the higher operating pressure of R744 (5–7 times higher than those of R455A and R463A), as well as requiring heavy equipment, but at optimal operating condition parameters, R744 and R-463A had a maximum COP of 14.58 and 14.19, respectively. The maximum COPs of R744, R455A, and R463A based on the optimal pressure of the cooler/condenser were 3.1, 4.25, and 5.4, respectively. Additionally, regarding the need for environmentally friendly air conditioning systems with acceptable performance in cars due to their impact on the environment and their contribution to global warming, the blend R455A is recommended for use as a refrigerant in AAC systems.

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Jung, Dongsoo, Kil-hong Song, Youngmok Cho und Sin-jong Kim. „Flow condensation heat transfer coefficients of pure refrigerants“. International Journal of Refrigeration 26, Nr. 1 (Januar 2003): 4–11. http://dx.doi.org/10.1016/s0140-7007(02)00082-8.

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27

Ross, H., R. Radermacher, M. di Marzo und D. Didion. „Horizontal flow boiling of pure and mixed refrigerants“. International Journal of Heat and Mass Transfer 30, Nr. 5 (Mai 1987): 979–92. http://dx.doi.org/10.1016/0017-9310(87)90016-0.

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Jing, Biyu, Di Xia und Guoqiang Wang. „Adsorption and Self-Diffusion of R32/R1234yf in MOF-200 Nanoparticles by Molecular Dynamics Simulation“. Processes 10, Nr. 9 (28.08.2022): 1714. http://dx.doi.org/10.3390/pr10091714.

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The thermophysical properties of a refrigerant can be modified via adding metal organic frameworks (MOF) to it. Understanding the adsorption–diffusion process of the mixture in MOFs at the molecular level is important to further improve the efficiency of the organic Rankine cycle. The adsorption and diffusion of R32/R1234yf in MOF-200 was investigated by molecular dynamics simulation in the present work. The results show that the number of adsorbed molecules of R32 in MOF-200 per unit mass is higher than that of R1234yf in the pure fluid adsorption system. The adsorption capacity of the mixture is lower than that of a pure working medium due to competitive adsorption. For both pure and mixed refrigerants, the adsorption heat of R32 in MOF-200 is smaller than that of R1234yf. Compared with R1234yf, the self-diffusion coefficient of R32 in MOF-200 is larger because of the lower diffusion activation energy.

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Feroiu, Viorel, und Dan Geanã. „Volumetric and thermodynamic properties for pure refrigerants and refrigerant mixtures from cubic equations of state“. Fluid Phase Equilibria 207, Nr. 1-2 (Mai 2003): 283–300. http://dx.doi.org/10.1016/s0378-3812(03)00034-7.

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30

Arcasi, A., R. Mastrullo, A. W. Mauro und L. Viscito. „Adiabatic frictional pressure gradient during flow boiling of pure refrigerant R1233zd and non-azeotropic mixtures R448A, R452A and R455A“. Journal of Physics: Conference Series 2177, Nr. 1 (01.04.2022): 012045. http://dx.doi.org/10.1088/1742-6596/2177/1/012045.

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Abstract The research on two-phase flow characteristics of refrigerants is of primary importance in several fields, such as air conditioning and refrigeration systems. Therefore, the determination of the pressure drop during flow boiling is important for the correct design of evaporators and heat spreaders systems. This paper presents a collection of experiments on flow boiling pressure drop using pure refrigerant R1233zd and new low-GWP refrigerant mixtures R448A, R452A and R455A. All tests were performed in adiabatic conditions, in a smooth horizontal stainless-steel tube having an internal diameter of 6.0 mm and a thickness of 1.0 mm. The effect of operating parameters, such as (bubble) saturation temperature (from 25 to 65 °C) and mass flux (from 150 to 600 kg/m2s) is investigated and discussed, and the performance of the chosen fluids is also compared. Finally, an assessment of existing prediction methods is carried-out to find the most suitable correlations for two-phase pressure drop evaluation.

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Jung, Dongsoo, Youngil Kim, Younghwan Ko und Kilhong Song. „Nucleate boiling heat transfer coefficients of pure halogenated refrigerants“. International Journal of Refrigeration 26, Nr. 2 (März 2003): 240–48. http://dx.doi.org/10.1016/s0140-7007(02)00040-3.

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Porto, Matheus P., Hugo T. C. Pedro, Luiz Machado, Ricardo N. N. Koury, Enio P. Bandarra Filho und Carlos F. M. Coimbra. „Optimized heat transfer correlations for pure and blended refrigerants“. International Journal of Heat and Mass Transfer 85 (Juni 2015): 577–84. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.01.102.

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Mehendale, Sunil S. „Condensing heat transfer of pure refrigerants and refrigerant mixtures flowing within horizontal microfin tubes: A new model“. International Journal of Refrigeration 103 (Juli 2019): 223–42. http://dx.doi.org/10.1016/j.ijrefrig.2019.04.015.

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34

Sami, S. M., und J. Schnotale. „Comparative study of two phase flow boiling of refrigerant mixtures and pure refrigerants inside enhanced surface tubing“. International Communications in Heat and Mass Transfer 19, Nr. 1 (Januar 1992): 137–48. http://dx.doi.org/10.1016/0735-1933(92)90071-o.

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35

Nasrifar, Khashayar, und Mahmood Moshfeghian. „Evaluation of saturated liquid density prediction methods for pure refrigerants“. Fluid Phase Equilibria 158-160 (Juni 1999): 437–45. http://dx.doi.org/10.1016/s0378-3812(99)00068-0.

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Mulero, A., M. I. Parra, K. K. Park und F. L. Román. „Vaporization Enthalpy of Pure Refrigerants: Comparative Study of Eighteen Correlations“. Industrial & Engineering Chemistry Research 49, Nr. 10 (19.05.2010): 5018–26. http://dx.doi.org/10.1021/ie901015f.

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37

Shin, Jee Young, Min Soo Kim und Sung Tack Ro. „Experimental study on forced convective boiling heat transfer of pure refrigerants and refrigerant mixtures in a horizontal tube“. International Journal of Refrigeration 20, Nr. 4 (Juni 1997): 267–75. http://dx.doi.org/10.1016/s0140-7007(97)00004-2.

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38

Sakina, Fara Nabilah, Habibatu Nihayah, Teguh Hady Ariwibowo und Lohdy Diana. „THERMODYNAMIC ANALYSIS OF RECUPERATIVE AND REHEAT BASED ON ORGANIC RANKINE CYCLE FOR HIGH-TEMPERATURE WASTE HEAT RECOVERY“. Jurnal Rekayasa Mesin 14, Nr. 1 (29.05.2023): 331–42. http://dx.doi.org/10.21776/jrm.v14i1.1310.

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Heat recovery from available waste heat is an essential method in renewable energy processes due to the ability to generate electricity by using Organic Rankine Cycles (ORC). The process model is developed with the Cycle Tempo software. Fluid properties were analyzed with Reference Fluid Properties (REFPROP) software. This research presents a thermodynamic comparison of the Basic Organic Rankine Cycle (BORC) and Recuperative Organic Rankine Cycle (RORC) for waste heat recovery applications using pure refrigerants R-141b, R-245fa, R-123, and R-21. By performing simulations for heat source high-temperatures ranging from 160 to 200 °C. The comparison between BORC and RORC performance parameters and refrigerant properties was evaluated on the heat source temperature. Research shows that RORC produces higher thermal efficiency but has lower irreversibility than BORC. RORC has a maximum thermal efficiency of 12.67%, and BORC has a thermal efficiency of 11.49% for refrigerant R-141b at a flue gas temperature of 160 °C. The thermal efficiency of the ORC increases as the temperature of the heat source increases.

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PARK, KYOUNG KUHN. „A SATURATED LIQUID DENSITY CORRELATION FOR PURE REFRIGERANTS AND OTHER SUBSTANCES“. International Journal of Air-Conditioning and Refrigeration 20, Nr. 02 (Juni 2012): 1250004. http://dx.doi.org/10.1142/s2010132512500046.

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A modification is proposed of the Chouaieb–Ghazouani–Bellagi (CGB) correlation for the saturated liquid density. After we examined the values of the critical exponent, which is a nonlinear parameter for the CGB correlation, we assumed that the exponent deviates by a small amount from the theoretical value of 0.325. Then, a Taylor-series expansion was conducted for the CGB correlation in order to develop a new correlation with two linear adjustable parameters. Data on the saturated liquid density for 70 pure fluids including 43 refrigerants from the NIST Chemistry WebBook in the whole vapor-liquid saturation range were fitted to the new and existing correlations. The results show that the new correlation yields better performance for substances of which reduced triple point temperature is higher than 0.4. Excellent performance (i.e., AAD < 0.1%) can be achieved with the modified CGB for 14 fluids but only for four fluids with the modified Guggenheim model.

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Zhi, Liang-Hui, Peng Hu, Long-Xiang Chen und Gang Zhao. „Viscosity prediction for six pure refrigerants using different artificial neural networks“. International Journal of Refrigeration 88 (April 2018): 432–40. http://dx.doi.org/10.1016/j.ijrefrig.2018.02.011.

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41

Tarrad, Ali Hussain, und Ayad Khudhair Al-Nadawi. „Modeling of Finned-Tube Evaporator using Pure and Zeotropic Blend Refrigerants“. Athens Journal of Τechnology & Engineering 2, Nr. 4 (30.11.2015): 263–82. http://dx.doi.org/10.30958/ajte.2-4-4.

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42

Sun, Zhaofu, Maoqiong Gong, Yanfeng Qi, Zhijian Li und Jianfeng Wu. „Nucleate pool boiling heat transfer of pure refrigerants and binary mixtures“. Journal of Thermal Science 13, Nr. 3 (August 2004): 259–63. http://dx.doi.org/10.1007/s11630-004-0040-5.

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43

Mimoune, Zoubeyr, Imad Anoune und Hakim Madani. „Implementation of PC-SAFT for Predicting thermodynamic properties of pure refrigerants and vapor-liquid equilibria of refrigerants binary mixtures.“ Fluid Phase Equilibria 573 (Oktober 2023): 113868. http://dx.doi.org/10.1016/j.fluid.2023.113868.

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44

Tyczewski, Przemysław. „Tribological Wear in the Complex Service Conditions“. Solid State Phenomena 225 (Dezember 2014): 101–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.225.101.

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This paper presents an attempt to learn mechanical, corrosive and abrasive wear mechanisms and wear mechanisms in refrigerating compressor systems. The range of author’s examinations includes electrolytic liquids with abrasive material used in the food industry, especially in the sugar industry and lubricating oils polluted with refrigerant occurring in stationary and mobile refrigerating compressor systems. Tests on the wear mechanisms in complex service conditions show that the total wear occurring in tribological pairs due to simultaneous occurrence of destructive processes: frictional, corrosive and abrasive, is not a simple superposition of their individual effects occurring in conditions of their independent interactions. On the basis of carried out experiments with the use of mathematical methods for experimental designs, a statistical model describing the complex process of simultaneous wear was formulated. This model enables forecasting the wear and indicates that the abrasive wear is of dominating character. In the compressor refrigerating systems, the oil–refrigerant system is characterized by complex relations. Refrigerants andcompressor oils create compounds causing the accelerated wear of refrigerating compressors. The complex dependencies in case of the oil–refrigerant compound, cause that the lubricating and anti-wear properties are much worse than in case of pure oil. In case of exceeding their mutual miscibility, part of the agent is absorbed by oil. More stringent regulations concerning the protection of the ozone layer lead to the appearance of new agents creating new compounds with oils. In order to examine the influence of the compounds on the wear processes in the refrigerating compressors, we made a test stand. The stand is built of real elements of the refrigerating system consisting of, among others, a dismountable half-hermetic compressor. The stand, built for testing the model wear processes occurring in the refrigerating compressors, will be used for tribological tests in the atmosphere of refrigerants under regular loads conditions.The purpose of the performed examination is to develop methods of wear phenomena modelling in the complex service conditions in the sectors of food production and refrigerated storage .

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45

Hong, Eul Cheong, Jee Young Shin, Min Soo Kim, Kyungdoug Min und Sung Tack Ro. „Prediction of forced convective boiling heat transfer coefficient of pure refrigerants and binary refrigerant mixtures inside a horizontal tube“. KSME International Journal 17, Nr. 6 (Juni 2003): 935–44. http://dx.doi.org/10.1007/bf02983408.

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46

Lee, Kyu Sun, Hong Gyu Jeon, Sung Oug Cho und Young Ze Lee. „Friction and Wear of Flange and Shaft in Compressor under the Environments of PAG Oil and Carbon Dioxide as a Refrigerant“. Key Engineering Materials 345-346 (August 2007): 1059–62. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1059.

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In order to protect the global environment, especially on the point of the greenhouse effect, carbon dioxide should be used as a natural refrigerant. Because new compressors with CO2 are going to be operated under the high pressure, the interaction between sliding surfaces in the compressor becomes very important. To develop new compressor, especially rotary type, the friction and wear characteristics of sliding surfaces were very important. In this paper, the surface interactions between a shaft and a flange, which were one of the contacting parts in compressor, were evaluated. The frictional forces and wear amounts in boundary lubricated sliding condition were measured using the pin-on-disk tester. Two types of refrigerants were used, namely R410A and CO2 to compare the tribological characteristics of conventionally used one with new natural refrigerant. It was found that CO2 lead to a bad lubricity as compared with R410A or pure oil due to the formation of relatively thin protective layer on the sliding surface. Smooth surface of shaft produced lower values of friction and wear than rough surfaces. The smooth surfaces represented much more spheroidal graphite, which had very favorable tribological characteristics, on the sliding surfaces.

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47

Li, Shengyu, und Jun Lu. „A Theoretical Comparative Study of Vapor-Compression Refrigeration Cycle using Al2O3 Nanoparticle with Low-GWP Refrigerants“. Entropy 24, Nr. 12 (13.12.2022): 1820. http://dx.doi.org/10.3390/e24121820.

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Nanorefrigerant is a mixture of nanoparticles and pure refrigerant, which can increase heat transfer characteristics in refrigeration and air conditioning equipment. The performance of four different Al2O3 nanorefrigerants and their pure fluids (R600a, R134a, R1234yf, and R1233zd(E)) is analyzed in a vapor-compression refrigeration cycle. The enthalpy of a nanorefrigerant in the refrigeration cycle is calculated by using the prediction method based on the density of nanorefrigerant. A numerical model is established for the thermodynamic analysis, and the results show that adding nanoparticles to the pure refrigerant enhances heat transfer in heat exchangers, increases cooling capacity, reduces compressor power consumption, and finally improves the performance of the refrigeration system. The COP improvement of R1233zd(E) + Al2O3 nanorefrigerant is the highest, and the COP improvement of R134a + Al2O3 and R1234yf + Al2O3 are close to each other. When the mass fraction of Al2O3 nanoparticles increases to 0.30%, the COP of R1233zd(E) and R600a increases by more than 20%; the maximum exergy efficiency is 38.46% for R1233zd(E) + Al2O3, and the minimum exergy efficiency is 27.06% for pure R1234yf. The results provide a basis for the application of nanorefrigerants in the vapor compression refrigeration cycle.

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Gupte, Neelkanth S., und Ralph L. Webb. „Convective Vaporization of Pure Refrigerants in Enhanced and Integral-Fin Tube Banks“. Journal of Enhanced Heat Transfer 1, Nr. 4 (1994): 351–64. http://dx.doi.org/10.1615/jenhheattransf.v1.i4.60.

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Sami, S. M., und C. Tribes. „Numerical prediction of capillary tube behaviour with pure and binary alternative refrigerants“. Applied Thermal Engineering 18, Nr. 6 (März 1998): 491–502. http://dx.doi.org/10.1016/s1359-4311(97)00048-3.

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50

Dewangan, Ashok K., Anil Kumar und Ravi Kumar. „Nucleate boiling of pure and quasi-azeotropic refrigerants from copper coated surfaces“. Applied Thermal Engineering 94 (Februar 2016): 395–403. http://dx.doi.org/10.1016/j.applthermaleng.2015.10.138.

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