Relevant bibliographies by topics / Zeotropic refrigerant

Academic literature on the topic 'Zeotropic refrigerant'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Zeotropic refrigerant"

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Nowak, Bernard, and Piotr Życzkowski. "THE EFFECT OF TEMPERATURE GLIDE OF R407C REFRIGERANT ON THE POWER OF EVAPORATOR IN AIR REFRIGERATORS / WPŁYW POŚLIZGU TEMPERATURY CZYNNIKA CHŁODNICZEGO R407C NA MOC PAROWNIKA CHŁODZIARKI POWIETRZA." Archives of Mining Sciences 58, no. 4 (December 1, 2013): 1333–46. http://dx.doi.org/10.2478/amsc-2013-0092.

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Abstract The article discusses the effect of the phenomenon of temperature glide of zeotropic refrigerants on thermal power of an evaporator in an air compression refrigerator. Zeotropic mixtures are subject to phase transitions, the process of which significantly differs from that of homogeneous refrigerants. In contrast to homogeneous refrigerants, where boiling and condensing processes take place at a constant temperature, for the zeotropic mixtures it is essential to know the vapor quality to unambiguously determine the temperature at which the evaporation process is initiated. The R407C refrigerant serves as an example to describe the method of determining the initial temperature of the evaporation process taking into account the effect of temperature glide. The developed formula (7) has been based on a proven linear course of isobars in the two-phase region (Fig. 5) and thus determining a polynomial describing their angle of inclination (8). In addition, temperature calculation formulas (9) and specific enthalpy (10) of dry saturated vapor of the R407C refrigerant have been presented as well. This approach allows to determine the temperature of the R407C refrigerant at the inlet to the evaporator without the required knowledge of its vapor quality. The previously used simplified methods for determining the temperature of a refrigerant at the inlet to the evaporator result in considerable deviations in calculated power of the evaporator compared with its actual value. The presented calculation example involving mine air compression refrigerator of TS-450P type shows that relative deviations of the evaporator thermal power may even exceed 20%. This example compares two simplified methods for determining zeotropic evaporating temperature of a refrigerant used in comparative calculations of refrigerants with the method presented in this article.
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Saengsikhiao, Piyanut, and Juntakan Taweekun. "The Data Mining Technique Using RapidMiner Software for New Zeotropic Refrigerant." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 83, no. 1 (June 3, 2021): 70–90. http://dx.doi.org/10.37934/arfmts.83.1.7090.

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This research presents the development of environmentally-friendly and energy efficient refrigerant for medium temperature refrigeration systems that new azeotropic refrigerant mixture of hydrofluorocarbons and hydrocarbon that can retrofit in the refrigeration system using R404A. The medium back pressure refrigeration testing standard that follow CAN/ANSI/AHRI540 standard air-conditioning, heating, and refrigeration institute (AHRI) and The properties of refrigerants and refrigeration simulation system that used national institute of standards and technology (NIST) reference fluid thermodynamic and transport properties database (REFPROP) software and NIST vapor compression cycle model accounting for refrigerant thermodynamic and transport properties (CYCLE_D-HX) software. The methodology uses decision tree function in datamining by rapid minor software that first of KDnuggets annual software poll that showed new azeotropic refrigerant mixture had cooling capacity, refrigerant effect, GWP and boiling point were lower than R404A but work and pressure for medium temperature refrigeration system of azeotropic refrigerant mixture were higher than R404A. The artificial intelligence (AI) by data mining technic can predictive environmentally-friendly and energy efficient refrigerant for medium temperature refrigeration. The result of refrigerant mixed by R134A, R32, R125 and R1270 and is consistent with the evolution of fourth-generation refrigerants that contain a mixture of HFCs and HCs which are required to produce a low-GWP, zero-ozone-depletion-potential (ODP), high-capacity, low-operating-pressure, and nontoxic refrigerant.
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Anusha Peyyala, M. Naga Swapna, B. Purna Chandra Sekhar, and B. Sunil. "Experimental investigation of cop for an air conditioner using zeotropic blend." Global Journal of Engineering and Technology Advances 6, no. 3 (March 30, 2021): 014–23. http://dx.doi.org/10.30574/gjeta.2021.6.3.0028.

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In this project an air conditioner was fabricated using R-410a as refrigerant and its COP is calculated. CFCs have been phased out, except for essential users, and HCFCs are to be eliminated by 2020, because of their ozone depletion potential.This generates a need for the investigation of zero ozone depletion potential (ODP) refrigerants or refrigerant blends.R410A is among newer brand of refrigerant blend, with zero ODP. The biggest difference to R22 is the pressure levels generated which are more than50% higher. The refrigerant R410A operates at higher pressure at the same saturated temperatures than R22, therefore system should be re designed. The overall COP of the system is 5 to 6% more than the R22. We also calculated the relative humidity of room air after it gets cooled, heat removed from the air by considering the input data from weather online which provides us the day to day climatic conditions. Present work provides us regarding performance of an self fabricated zeotropic air conditioner.
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Sivakumar, Mayilsamy, and Periasamy Somasudaram. "Thermodynamic investigations of Zeotropic mixture of R290, R23 and R14 on three-stage auto refrigerating cascade system." Thermal Science 20, no. 6 (2016): 2073–86. http://dx.doi.org/10.2298/tsci140103091s.

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The zeotropic mixture of environment friendly refrigerants (hydrocarbons and hydrofluorocarbons) being the only alternatives for working fluid in low temperature refrigeration system. Hence, three-stage auto refrigerating cascade system was studied for the existence using four combinations of three-component zeotropic mixture of six different refrigerants. The exergy analysis confirmed the existence of three-stage auto refrigerating cascade system. The performances of the system like coefficient of performance, exergy lost, exergic efficiency, efficiency defect, and the evaporating temperature achieved were investigated for different mass fractions in order to verify the effect of mass fraction on them. In accordance with the environmental issues and the process of sustainable development, the three-component zeotropic mixture of R290/R23/R14 with the mass fraction of 0.218:0.346:0.436 was performing better and hence can be suggested as an alternative refrigerant for three-stage auto refrigerating cascade system operating at very low evaporating temperature in the range of ?97?C (176 K), at coefficient of performance of 0.253 and comparatively increased exergic efficiency up to 16.3% (58.5%).
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Chen, J., and H. Kruse. "Calculating Circulation Concentration of Zeotropic Refrigerant Mixtures." HVAC&R Research 1, no. 3 (July 1, 1995): 219–31. http://dx.doi.org/10.1080/10789669.1995.10391320.

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El-Sayed, A. R., M. El Morsi, and N. A. Mahmoud. "A Review of the Potential Replacements of HCFC/HFCs Using Environment-Friendly Refrigerants." International Journal of Air-Conditioning and Refrigeration 26, no. 03 (September 2018): 1830002. http://dx.doi.org/10.1142/s2010132518300021.

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The adequate and efficient performance of HVAC systems are signs of luxury and human comfort, and the improvement of their performance has been the target of continuous researches. Choosing the suitable refrigerant is the main parameter in matching the system components, selecting the type of heat exchangers, the compressor, the expansion device and the suitable lubricant. The theoretically ideal refrigerant is the one having zero ozone depletion potential (ODP), low global warming potential (GWP), nontoxic, nonflammable, has appropriate thermodynamic and heat transfer properties and is compatible with any type of lubricating oil. Chlorinated, fluorinated refrigerants, zeotropic and azeotropic mixtures satisfy many requirements, but have high ODP and GWP and are not compatible with all types of oil. Hydrocarbons (HCs) satisfy all the requirements except being highly flammable. This work reviews previous research aiming to find substitutes for the environmentally harmful refrigerants by other environmentally friendly ones and compare their performance in various HVAC appliances.
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Hambarde, M. D., Ramakant Shrivastava, S. R. Thorat, and O. P. Dale. "Experimental investigation on evaporation of R407C in a single horizontal smooth tube." IRA-International Journal of Technology & Engineering (ISSN 2455-4480) 7, no. 2 (S) (July 10, 2017): 266. http://dx.doi.org/10.21013/jte.icsesd201726.

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Due to higher ozone layer depletion potential of HCFC refrigerant, R22 which has been mostly used in house hold refrigeration will be phased out by 2020 as per Montreal Protocol and UNFCCC Regulations. R407C, a zeotropic refrigerant from HFC category is a promising refrigerants in place of R22. Performance evaluation of R407 is required to enhance its application in house hold refrigeration. Hence an experimental investigation is carried out to understand the heat transfer characteristics during flow boiling of R407C in a smooth horizontal tube of 13.386 mm inner diameter and 2m length. The experiment is performed under the operating conditions; (i) mass flux range 100 to 300 kg s-1m-2; (ii) heat flux within range 2 to 7 kWm-2; (iii) temperature range at inlet to test section -100C to +100C; (iv) average vapor quality within test section from 0.05 to 0.95.The effect of heat flux, mass flux, vapor quality, temperature glide on heat transfer coefficient, during evaporation of R407C are examined.
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Ardita, I. Nengah, I. Gusti Agung Bagus Wirajati, I. Dewa Made Susila, and Sudirman Sudirman. "Performance analysis of retrofit R410a refrigerant with R32 refrigerant on a split air conditioner." Journal of Applied Mechanical Engineering and Green Technology 2, no. 1 (March 31, 2021): 1–4. http://dx.doi.org/10.31940/jametech.v2i1.2459.

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Split air conditioning (AC) is the most widely used in the community for both commercial and domestic utilities. At the present refrigerant which used in Split AC is mostly common group of HFCs, such as R410a. R410a is a zeotropic refrigerant and if there is a leak in the system, it cannot be added this refrigerant. This will increase the cost of maintenance. The aims of this research is to investigate the retrofit of R410a with R32 on the Split AC system. The R32 is chosen because it has higher latent evaporation heat at the same temperature and has less effect on global warming. The refrigeration effect, the power consumption and the system performance are the main three quantities that want to be examined in this research which are observed before and after retrofit. Experimental investigation conducted during this research, including design and manufacture of experimental equipment, calibration and tools installment, collecting the experimental data and analysis by quantitative description method before and after retrofit. The results informed that cooling effect increased during the research, but the COP system has a slight decrease about 4%. R32 refrigerant is quite feasible as a retrofit refrigerant to R410a refrigerant.
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Smit, F. J., J. R. Thome, and J. P. Meyer. "Heat Transfer Coefficients During Condensation of the Zeotropic Refrigerant Mixture HCFC-22/HCFC-142b." Journal of Heat Transfer 124, no. 6 (December 1, 2002): 1137–46. http://dx.doi.org/10.1115/1.1484108.

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Heat transfer coefficients during condensation of zeotropic refrigerant mixtures were obtained at mass fractions of 90 percent/10 percent, 80 percent/20 percent, 70 percent/30 percent, 60 percent/40 percent, and 50 percent/50 percent for HCFC-22/HCFC-142b and for pure HCFC-22 in a horizontal smooth tube at a high saturation pressure of 2.43 MPa. The measurements were taken in a series of eight 8.11 mm inner diameter smooth tubes with lengths of 1 603 mm. At low mass fluxes, from 40 kg/m2s to 350 kg/m2s where the flow regime is predominately stratified wavy, the refrigerant mass fraction influenced the heat transfer coefficient by up to a factor of two, decreasing as the mass fraction of HCFC-142b is increased. At high mass fluxes of 350 kg/m2s and more, the flow regime was predominately annular and the heat transfer coefficients were not strongly influenced by the refrigerant mass fraction, decreasing only by 7 percent as the refrigerant mass fraction changed from 100 percent HCFC-22 to 50 percent/50 percent HCFC-22/HCFC-142b. The results also indicated that of three methods tested to predict heat transfer coefficients, the flow pattern correlation of Dobson and Chato (1998) gave the best results for pure HCFC-22 and for the mixtures utilizing the Silver-Bell-Ghaly method (1964).
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Bohdal, Tadeusz, Katarzyna Widomska, and Małgorzata Sikora. "The analysis of thermal and flow characteristics of the condensation of refrigerant zeotropic mixtures in minichannels." Archives of Thermodynamics 37, no. 2 (June 1, 2016): 41–69. http://dx.doi.org/10.1515/aoter-2016-0012.

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Abstract The paper presents the results of experimental heat transfer and pressure drop during condensation of the single component refrigerant R134a and zeotropic mixtures R404A, R407C, and R410A in tube minichannels of internal diameter from the range 0.31-3.30 mm. The local values and the average of heat transfer coefficient and pressure drop in the whole range of the change in mass quality were measured. On the basis of the obtained test results there was illustrated the influence of the change of mass vapor quality, the mass flux density, and the inner diameter of channel on the studied parameters. These results were compared with the calculation results based on the relations postulated by other authors. The discrepancy range was ± 50%. On the basis of given test results own correlation was developed to calculate the heat transfer coefficient and pressure drop of tested refrigerants which presents the obtained results in a range of discrepancy of ±25%.
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Dissertations / Theses on the topic "Zeotropic refrigerant"

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Milkie, Jeffrey A. "Condensation of hydrocarbon and zeotropic hydrocarbon/refrigerant mixtures in horizontal tubes." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51825.

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An experimental investigation of condensation of hydrocarbons and hydrocarbon/refrigerant mixtures in horizontal tubes was conducted. Heat transfer coefficients and frictional pressure drops during condensation of a zeotropic binary mixture of R245fa and n-pentane in a 7.75 mm internal diameter round tube were measured across the entire vapor-liquid dome, for mass fluxes ranging from 150 to 600 kg m-2 s-1, and reduced pressures ranging from 0.06 to 0.23. Condensation experiments were conducted for the mixture, as well as its pure constituents over a similar range of conditions. In addition, condensing flow of the hydrocarbon propane was documented visually using high-speed video recordings. Results from these experiments were used to establish the two-phase flow regimes, void fractions, and liquid film thicknesses during condensation of propane flowing through horizontal tubes with internal diameters of 7 and 15 mm. These measurements were made over mass fluxes ranging from 75 to 450 kg m-2 s-1, operating pressures ranging from 952 to 1218 kPa, and vapor qualities ranging from 0.05 to 0.95. Liquid film thickness and void fraction data were subsequently be used to assist the development of heat transfer and pressure drop models. In particular, the heat transfer coefficients and pressure drops observed in the mixture were compared with the corresponding values for the pure constituents. Models for heat transfer and pressure drop in the pure components as well as the mixtures were developed based on the data from the present study. This work extends the available literature on two-phase flow regimes for air-water mixtures, steam, and refrigerants to include hydrocarbons. Additionally, the limited information on condensation in multi-constituent hydrocarbon-hydrocarbon and refrigerant-refrigerant mixtures was extended to include hydrocarbon-refrigerant mixtures. The findings of this study are expected to benefit applications such as refrigeration, low-grade heat-driven power generation, and the development of heat exchangers for the chemical and process industries.
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Mirza-Tolouee, Changiz M., and n/a. "Experimental study of zeotropic refrigerant mixture HFC-407C as a replacement for HCFC-22 in refrigeration and air-conditioning systems." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20070416.141307.

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HCFC-22 is the world�s most widely used refrigerant. It serves in both residential and commercial applications, from small window units to large water chillers, and everything in between. Its particular combination of efficiency, capacity and pressure has made it a popular choice for equipment designers. Nevertheless, it does have some ODP, so international law set forth in the Montreal Protocol and its Copenhagen and Vienna amendments have put HCFC-22 on a phase out schedule. In developed countries, production of HCFC-22 will end no later than the year 2030. Zeotropic blend HFC-407C has been established as a drop-in alternative for HCFC-22 in the industry due to their zero Ozone Depletion Potential (ODP) and similarities in thermodynamic properties and performance. However, when a system is charged with a zeotropic mixture, it raises concerns about temperature glide at two-phase state, differential oil solubility and internal composition shift. Not enough research has been done to cover all aspects of alternative refrigerants applications in the systems. This research intended to explore behavior of this alternative refrigerants compare to HCFC-22 and challenges facing the industry in design, operation service and maintenance of these equipments. The purpose of this research is to investigate behavior of R407C refrigerant in chiller systems. This includes performance and efficiency variations when it replaces R22 in an existing system as well as challenges involved maintaining the system charged with R407C. It is a common practice in the industry these days to evacuate and completely recharge when part of the new refrigerant blend was leaked from the system. This has proved to be extremely costly exercise with grave environmental ramifications. This research is intended to address challenges faced in the real world and practical terms. Theoretical and experimental approaches used as a methodology in this work. The system mathematically modeled to predict detailed system performance and effect of the leak at various conditions. To make this feasible and accurate enough, two separate approaches made, first system performance for pure R22 and R407C, and second system subjected to range of leak fractions. The earlier model was relatively straight forward when compared to the latter. Modeling a system charged with R407C ternary mixture and subjected to range of leaks posed enormous challenges. A sophisticated experimental test apparatus was also designed and built. Comprehensive and detailed tests at various conditions were conducted with special attention on instrumental accuracy and correct methodology. The first part has been successfully modeled and predicted all the factors and performance with excellent accuracy when compared to the test results. In these approaches pure refrigerants R22 and R407C were used and simulated the system behavior at range of conditions. However, the second part was the most challenging ever. Comprehensive leak process simulations produced trends of R32/R125/R134a composition change as function of rate of leak. Starting from this point, equations have been created to represent the composition change as function of percentage of the leak. The system thermodynamic cycle was also modeled to calculate capacity, power input and COP at the range of the conditions. Despite many affecting parameters and complexity of the model, the mathematical model successfully predicted the test outcome with a very reasonable accuracy, averaging around 3% with some times reaching to 5 to 6%. On the experimental stage the system charged with the new HFC-407C was deliberately subjected to refrigerant leak at various leak stages. The aim was to objectively determine to what extend the gas leak can be still acceptable without going through the expensive complete gas charge. The effect of leak was tested and verified at 10% steps, from 10% up to 50% mass fraction for the total charge. It has been observed that at the leaks beyond 30%, the adverse effect on the capacity becomes more significant, from 8 to about 15% decrease. While the power input decreased at slower pace, from 3% up to about 8% depending on the test conditions. This translated to COP decrease ranging from 4 to about 7%. This capacity loss and efficiency decrease are significant figures which suggests that the system, here chiller, can not be allowed to degrade the performance to that extend and still continue operating.
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Visagie, Pieter Johannes Jacobus. "The analysis of an ammonia/water hybrid heat pump in the ethanol production process / by Pieter J.J. Visagie." Thesis, North-West University, 2008. http://hdl.handle.net/10394/2529.

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Ethanol is a renewable energy source that could decrease society's dependence on fossil fuels, while reducing greenhouse gas emissions. Producing ethanol on a small scale on South African farms could provide farmers with the capability of increasing their profits by reducing their input cost. Ethanol can be directly used as fuel and could supply alternative products to their market. This study evaluated the feasibility of using an ammonia/water hybrid heat pump in the ethanol production process. A model for the material and energy balance of a small scale ethanol plant was simulated, to obtain the requirements to which the hybrid heat pump had to adhere. A two stage hybrid heat pump (TSHHP) was then modelled. It is capable of operating at high temperatures and it has high temperature lift capabilities, which are suitable in the production of ethanol. The results from the model demonstrated that the TSHHP could operate at an average temperature lift of 106°C with a maximum temperature of heat delivery as high as 142°C and cooling as low as 9°C. Simultaneous heating and cooling demand in the ethanol production process can be met with the TSHHP. For the TSHHP model, 120 kW of heating and 65 kW of cooling is supplied while maintaining a COP of 2.1. The model accuracy was also verified against another simulation program. Implementation of the TSHHP into the ethanol plant was then discussed, as well as methods to optimize production by energy management. When compared to conventional heating and cooling systems, it was found that the TSHHP provides a more cost effective and energy efficient way of producing ethanol. The economic evaluation demonstrated that the installation cost of the TSHHP would only be 63% of the price of a conventional system. The main advantage is that the TSHHP uses only 38% of the energy used in a conventional system.
Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2009.
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Al-Bakri, Basim Abdulrazzak. "Micro-channel air cooled condenser performance with two-phase flow of zeotropic refrigerant at high ambient temperatures." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/20646/.

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A study of the thermal performance of an air-cooled micro-channel condenser using zeotropic refrigerant blend R-410A operating at high reduced pressure and at hot climate was conducted. The investigation of the condensation process at high ambient temperature is worth considering because the condensation saturation temperature should be high enough to be cooled by air at high ambient temperature. In this case a high operating pressure corresponding to the high condensation temperature is required; therefore, the condensation process of R-410A occurs at near-critical pressure and the vapour compression cycle operates in hot weather. In order to achieve a successful condensation process operating at hot climate, micro-channel tubes were suitable because of the high heat transfer coefficient associated with tubes of very small hydraulic diameter. The local heat transfer coefficient of R-410A was determined experimentally during the condensation process across the vapour-liquid dome at 0.7 and 0.8 reduced pressures and at 35 and 45°C ambient air temperatures, in two different rectangular tubes of Dₕ* =1.26 and 0.52 mm, over a mass flux range of 200≤G*≤800 kg/ m2s. Although, the temperature glide of the refrigerant R-410A was sufficiently small, the measurement of the mass flux and the heat transfer during condensation with other measuring parameters were always difficult to achieve with a high level of accuracy. The latest technology of the micro-foil heat flux sensor technique was used with a bespoke facility to accurately determine the heat duty of condensation along the micro-channel tubes. The behaviour of the heat transfer coefficient with the vapour quality was addressed. In addition, the behaviour of heat flux, vapour quality and wall temperature with the thermal length of the channel were intensively studied. The heat transfer coefficient was found to increase with the mass flux and the vapour quality and to decrease with the ambient temperature. Correlations by other researchers mostly disagreed with the present experimental data. Annular flow regime was adopted due to the cross section of tubes at these diameters. A new correlation in annular flow regime that accounted for the effect of near critical pressure of such refrigerant and the high temperature of the coolant air in the geometry of tubes under consideration was proposed to predict the heat transfer coefficient of condensation for which the available models are insubstantial. The resulting correlation successfully computed the experimental data. The physical comprehension and correlation resulting from this research contribute to enhance the existing knowledge for designing and optimising new equipment that utilise R-410A for air-conditioning and refrigeration applications, particularly in hot climates.
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Chalidapongse, Prasai. "Steady-state and dynamic behaviour of plate-fin-tube direct expansion evaporators when using a zeotropic refrigerant mixture." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1444141/.

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Both steady-state and dynamic simulations of the operation of plate-fin-tube air coolers, under dry and wet conditions, and also of themostatic expansion valve (TEV) controlled coils under dry condition, were carried out. The investigation aimed at improving our understanding as how the operation behaviour of the cooler coils, under various coil conditions, was influenced by the use of a ternary refrigerant mixture (R407C) when compared to a pure refrigerant (R134a). Based on practical coil configurations, a distributive computer model was implemented, with governing equations for air and refrigerant sides and for tube walls set up for individual coil elements. For the TEV, equipped with an external equalizer, energy and force equations were set up. To compare the two refrigerants, a reference scheme, obtained based on the steady state simulation, was set up: the same air coil-inlet conditions, the same refrigerant mass flow rates and vapour qualities at the coil inlets, and the same refrigerant temperatures at the coil outlet. The dynamic simulation was based on having a step change in the coil inlet dry-bulb (DB) temperature. The analysis and discussion focussed on the temperature gliding and many other inter-related parameters/factors, e.g. the heat transfer coefficient (HTC), the coil arrangement, the refrigerant superheat and the refrigerant type. It was observed that for steady-state, the temperature gliding affected the spatial gradient of the temperature and humidity ratio of the tube-wall, the outlet dry-bulb temperature of the coil-face row, and the row outlet humidity ratio (HR). The temperature glide, when combined with the refrigerant HTC and the coil arrangement, had a strong influence on the sensible and latent heat fluxes, i.e. suppressing the influence of other parameters such as the effective air-side heat transfer and mass transfer coefficients. For the coil dynamics, the refrigerant temperature gliding influenced the gradients of the time profiles of the DB temperature and HR at the coil-outlet tubes that were unaffected by the superheat. For the TEV-controllcd coils, only the temperature gliding-up of R407C, not the temperature drop associated with R134a, was shown to have an impact upon the rate of change of the superheat-initiation location. The combined effect of the temperature gliding and the HTC influenced the transit times between steady states of both the superheat-initiation location and external-equalizer pressure.
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6

Mirza-Tolouee, Changiz M. "Experimental study of zeotropic refrigerant mixture HFC-407C as a replacement for HCFC-22 in refrigeration and air-conditioning systems." Australasian Digital Thesis Program, 2006. http://adt.lib.swin.edu.au/public/adt-VSWT20070416.141307/index.html.

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Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, 2006.
A thesis submitted for the degree of Doctor of Philosophy, School of Engineering and Science, Swinburne University of Technology, 2006. Typescript. Includes bibliographical references (p. 123-127).
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7

Wang, Pei-Yi, and 王姵懿. "Study on Low-Temperature Auto-Cascade Refrigeration Systems Operating with Zeotropic HC Refrigerant Mixtures." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/7p3xg7.

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碩士
國立臺北科技大學
能源與冷凍空調工程系碩士班
99
The temperature of the freezer ranging from -40 to -160℃ is widely used in cryomedicine, energy, biotechnology as cryopreservation. The system used to zeotropic refrigerant mixtures and single compressor, through zeotropic refrigerant mixture in the high boiling point and low boiling point in order to achieve the natural separation between the multi-level series with the stack method, to take the system from -40 to -160℃ temperature purposes. The feature of the auto-cascade refrigeration systems is affected by zeotropic refrigerant mixtures therefore the composition of the refrigerant and mass fraction are the key factors.The purpose of this study is to investigate auto-cascade refrigeration systems as the object of study, use simulation to look into the application of zeotropic HC refrigerant mixtures of R170/R290, R170/R1270, R170/R600 and 170/R600a to coefficient of performance (COP), and do a comprehensive appraisal of the composition of refrigerant. According to the research, in the same design conditions, R170/R290, R170/R1270, R170/R600, and R170/R600a zeotropic refrigerants mixture the best performance value and size of the sequence is: R170/R600(COP=1.34)>R170/R600a(0.82)>R170/R290(0.36)>R170/R1270(0.34), and the corresponding ratio of the best refrigerants composition were: 0.16,0.22,0.34,0.31. To R170/R1270 mixed refrigerant as a benchmark, the benchmark value of 1, R170/R600, R170/R600a, R170/R290 mixed refrigerant composition with the ratio of 3.92:2.41:1.06:1.
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Tang, Hsin-Chuan, and 唐欣傳. "Study on Low-Temperature Auto-Cascade Refrigeration Systems with Regenerator and Zeotropic Refrigerant Mixtures." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/tb5w4p.

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碩士
國立臺北科技大學
能源與冷凍空調工程系碩士班
100
With the development of technology, the requirement for cryogenic freezing is getting stricter in the scope of energy, military, bio-tech, and medical. Especially in medical, the cell preservation technique is the key of graft. Auto-cascade system uses zeotropic mixture as refrigerant to implement the natural separation and multi-stage cascade through the temperature glide for getting low temperature of -60°C to -160°C. The performance of Auto-cascade system is mainly affected by the zeotropic refrigerant, so the key point is to select the composition and fraction. The major issue of this study is to probe into the best fraction and COP of R1150/R290, R1150/R1270, R1150/R600, and R1150/R600a mixtures in Auto-cascade system with Regenerator through the theoretical analyzing. The study shows that 1). R1150/R600 mixture has the best COP 2.01 with R1150 mass fraction of 0.11, 2). The best COP 2.01 of R1150/R600 mixture is greater than the best COP 1.34 of R170/R600 mixture, 3). The best COP of R1150/R600 Auto-cascade with Regenerator has COP 2.21, which is greater than the value 2.01 of COP without Regenerator.
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Lin, Cheng-Te, and 林政德. "Performance Analysis for A Condenser with Zeotropic Refrigerants by ε-NTU Method." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/65606358715267651623.

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碩士
國立成功大學
機械工程學系專班
91
It has been a common practice for using a computer code to design an air-cooled condenser. However, the prediction is often too optimistic if the same code developed for pure refrigerants is directly applied for zeotropic refrigerants. This kind of prediction discrepancy is believed caused by the temperature glide and the extra resistance due to the mass transfer during the condensing process of a zeotropic refrigerant. In this study, the condenser is divided into many blocks. The degree of temperature glide of block in the saturated area will become relatively small for neglect during simulation, and then can be solved by the —NTU method. After each simulation in saturated area, the effect of temperature glide will take into consideration by setting the outlet condition of downstream block. The effect extra thermal resistance due to the mass transfer during condensing process is considered by using the modified correlations published in literatures for zoetropic refrigerants. We adopted various test datas published in literatures to verify the developed computer program, and the predicted results are generally agreed with experimental data. This program is then applied the design a typical air-cooled condenser. The working fluid of this condenser is R-407C refrigerant flowing in micro-fin tube, and the air-side has a wavy-fins. The optimal outer-fin number per unit length and the frontal velocity of condenser can be obtained by the calculated results using the developed computer code.
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10

Chen, Guan-Jie, and 陳冠杰. "A Heat Transfer Study of Falling Film Evaporation and Pool Boiling on Zeotropic Refrigerants." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/pgjd74.

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碩士
國立臺北科技大學
能源與冷凍空調工程系
106
This study investigates the heat transfer performance of thin film vaporization and pool boiling for various pure and mixed refrigerants at different saturation temperatures ranging from 25 to 70oC. The tested refrigerants are R245fa, R152a, R245fa/R152a mixtures with (3:1) and (1:3) mass ratios. Both smooth tube and 60 FPI finned tube are tested at the flow rates of 150 and 240 ml/min with the heat flux varied between 8.2 kW/m2 and the maximum heat flux. It is found that the heat transfer coefficient of the smooth tube increases with the increase of saturation temperature. However, the heat transfer coefficient of the fin tube shows opposite trend. This is because that the surface tension decreases with increasing saturation temperature, which helps to reduce the occurrence of dryness by spreading liquid in the fin gaps. Consequently, insufficient flow and uneven distribution of the liquid film, resulting in a decrease in the heat transfer coefficient. The enhancement of heat transfer by the fins in pure refrigerant is more pronounced than that of mixed refrigerants. The heat transfer enhancement ratio of the finned tube is 1.72~5.52 as compared with the smooth tube in R245fa at saturation temperature of 25~70℃. The enhancement ratio decreases with increasing iii saturation temperature. The experimental results show that the boiling heat transfer coefficient increases with increasing reduced pressure. The dependency of the heat transfer coefficient on reduced pressure of a mixture is not as strong as that as in a pure fluid. Pure refrigerant R152a yields higher falling film evaporation and boiling heat transfer coefficients than pure R245fa and the other two mixed refrigerants tested in this study.
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Books on the topic "Zeotropic refrigerant"

1

The performance of chlorine-free binary zeotropic refrigerant mixtures in a heat pump. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1991.

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2

1937-, Didion D. A., National Institute of Standards and Technology (U.S.), and Air and Energy Engineering Research Laboratory, eds. The performance of chlorine-free binary zeotropic refrigerant mixtures in a heat pump. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1991.

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3

Piotr, Domanski, Muller Jaroslaw, and National Institute of Standards and Technology (U.S.), eds. A study of water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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Piotr, Domanski, Muller Jaroslaw, and National Institute of Standards and Technology (U.S.), eds. A study of water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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Piotr, Domanski, Muller Jaroslaw, and National Institute of Standards and Technology (U.S.), eds. A study of water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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6

Piotr, Domanski, Muller Jaroslaw, and National Institute of Standards and Technology (U.S.), eds. A study of water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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Piotr, Domanski, Muller Jaroslaw, and National Institute of Standards and Technology (U.S.), eds. A study of water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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8

A study of a water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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9

A, Silk Eric, Domanski Piotr, and National Institute of Standards and Technology (U.S.), eds. A water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures with and without an internal heat exchanger. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 2000.

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10

A, Silk Eric, Domanski Piotr, and National Institute of Standards and Technology (U.S.), eds. A water-to-water heat pump using hydrocarbon and hydrofluorocarbon zeotropic mixtures with and without an internal heat exchanger. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 2000.

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Book chapters on the topic "Zeotropic refrigerant"

1

Kazi, Juned R., and Neeraj Agrawal. "Experimental Investigation of Dehumidifier Hybrid Air Conditioner Integrated Zeotropic Refrigerant Blend R-407C Air Source Water Heat Pump." In Renewable Energy and Climate Change, 175–83. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9578-0_16.

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2

Meyer, J. P. "Evaluation of Energy Efficient and Environmentally Acceptable Pure and Zeotropic Refrigerants in Air-Conditioning and Refrigeration." In Energy and the Environment, 239–46. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4593-0_21.

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3

Bivens, D. B., and A. Yokozeki. "HEAT TRANSFER OF ZEOTROPIC REFRIGERANT MIXTURES." In Heat Pumps for Energy Efficiency and Environmental Progress, 127–34. Elsevier, 1993. http://dx.doi.org/10.1016/b978-0-444-81534-7.50021-8.

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4

"A Method Based on the Fluctuation of the Temperature Difference to Select the Zeotropic Refrigerant Mixture in the Air-Conditioning Condition." In Inaugural US-EU-China Thermophysics Conference-Renewable Energy 2009 (UECTC 2009 Proceedings), 1–7. ASME Press, 2009. http://dx.doi.org/10.1115/1.802908.paper33.

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Al-Nadawi, Ayad Khudhair. "Distributed parameters modeling for heat exchangers using pure and zeotropic blend refrigerants." In Advanced Analytic and Control Techniques for Thermal Systems with Heat Exchangers, 49–129. Elsevier, 2020. http://dx.doi.org/10.1016/b978-0-12-819422-5.00003-7.

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Conference papers on the topic "Zeotropic refrigerant"

1

Abadi, Gholamreza Bamorovat, and Kyung Chun Kim. "PERFORMANCE IMPROVEMENT OF EVAPORATORS WITH ZEOTROPIC REFRIGERANT MIXTURE USING METAL FOAMS." In Second Thermal and Fluids Engineering Conference. Connecticut: Begellhouse, 2017. http://dx.doi.org/10.1615/tfec2017.bev.018370.

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Ju, Fujun, Xiaowei Fan, and Yaping Chen. "Theoretical Study of Heat Pump System Using R744/R1234yf as Refrigerant." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-53800.

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In this paper, the eco-friendly zeotropic mixture, R744/R1234yf was chosen as the alternative refrigerant in the instant heat pump water heater system. The cycle performance of heat pump was analyzed theoretically under the nominal working condition of heat pump system. The prediction results show that the new mixture has significant advantages for the instant heat pump with a large heat-sink temperature lift, and there exists an optimal mass fraction of R744/R1234yf, at which the maximum COPh should be obtained. The optimal mass fraction of R744/R1234yf is 17/83 and the system COPh should be attained to 4.29.
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3

Li, Shulei, Rui Zhu, Gongnan Xie, Yiqiang Jiang, and Weihua Cai. "The Condensation Heat Transfer Characteristics of Zeotropic Hydrocarbon Mixtures in a Helical Pipe." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23882.

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Abstract In order to explore tube-side heat transfer characteristics in the spiral wound heat exchange (SWHE) used in liquid natural gas (LNG) plants, the study on zeotropic hydrocarbon mixtures condensation heat transfer in a helical pipe is proposed. Firstly, based on two-fluid model and thermal phase change model, a numerical method coupling with empirical correlations is established to predict condensation heat transfer for zeotropic mixtures, in which the mixed effects are taken into account. Meanwhile, the rationality of the above methods is verified based on existing experimental results. Then, the effects of refrigerant components and operating parameters on flow patterns, heat transfer coefficients and heat and mass transfer resistance are discussed as the ranges of mass flux, saturation pressure and vapor quality are 200–800 kg/(m2·s), 2–4MPa and 0.15–0.90, respectively. It can be found that the predicted results coincide with the experimental ones, with deviations within ±15%. For different zeotropic hydrocarbon mixtures, as the vapor quality increases, the stratified flow, half-annular flow and annular flow appears in turn. The condensation heat transfer coefficients are always smaller than film heat transfer coefficients owing to the existence of heat and mass transfer resistance in vapor core. Besides, both film and condensation heat transfer coefficients increase with the increase of vapor quality and mass flux, while decrease with the rise in saturation pressure. Further, heat and mass transfer resistances increase as the vapor quality and saturation pressure increase and the mass flux decreases. In addition, compared to methane/ethane/propane/nitrogen (65/25/5/5, mole%) mixture, the averaged heat transfer performance for methane/ethane (90/10, mole%) mixture improves by 19.55%, whereas, the average heat and mass transfer resistance decreases by 53.51%. This study is helpful for understanding the zeotropic mixtures condensation in tubes and gives some suggestions for the choice of refrigerant components used in LNG SWHE, to design more effective SWHE.
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Wang, Huitao, Hua Wang, and Zhong Ge. "A Novel Criterion to Evaluate the Temperature Match Across a Heat Exchanger with Zeotropic Refrigerant Mixtures." In 2010 International Conference on Digital Manufacturing and Automation (ICDMA). IEEE, 2010. http://dx.doi.org/10.1109/icdma.2010.280.

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Middleton, Bobby D., Patrick V. Brady, and Serafina Lawles. "The Sandia National Laboratories Natural Circulation Cooler." In ASME 2021 Power Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/power2021-65399.

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Abstract Sandia National Laboratories (SNL) is developing a cooling technology concept — the Sandia National Laboratories Natural Circulation Cooler (SNLNCC) — that has potential to greatly improve the economic viability of hybrid cooling for power plants. The SNLNCC is a patented technology that holds promise for improved dry heat rejection capabilities when compared to currently available technologies. The cooler itself is a dry heat rejection device, but is conceptualized here as a heat exchanger used in conjunction with a wet cooling tower, creating a hybrid cooling system for a thermoelectric power plant. The SNLNCC seeks to improve on currently available technologies by replacing the two-phase refrigerant currently used with either a supercritical fluid — such as supercritical CO2 (sCO2) — or a zeotropic mixture of refrigerants. In both cases, the heat being rejected by the water to the SNLNCC would be transferred over a range of temperatures, instead of at a single temperature as it is in a thermosyphon. This has the potential to improve the economics of dry heat rejection performance in three ways: decreasing the minimum temperature to which the water can be cooled, increasing the temperature to which air can be heated, and increasing the fraction of the year during which dry cooling is economically viable. This paper describes the experimental basis and the current state of the SNLNCC.
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Kale, Kaustubh S., and Sunil S. Mehendale. "Novel Application-Specific Methodology for the Assessment of Microfin Tube Condensation Heat Transfer Correlations." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51908.

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Extensive critical study of five popular microfin tube correlations for condensation heat transfer coefficients (HTCs) was carried out. The principal aim of this investigation was to develop an application-specific quantitative tool to assess the predictive accuracy and applicability of these correlations for halogenated refrigerants as well as CO2. This novel methodology was developed and validated against a dataset of 1163 experimental data points for CO2, R22, R134a, R410A, R407C, R125 and other halogenated refrigerants obtained from a large number of published works which included diverse microfin tube geometries and condensing conditions. The tool will enable the engineer or experimentalist to select the best (i.e., most accurate) condensation HTC correlation for a given microfin tube application, thereby significantly reducing tube testing costs, leading to lower turn-around times and more efficient designs. Based on the analysis carried out using the new methodology, it was found that overall, Cavallini et al. (2009) was the most widely applicable and accurate flow condensation correlation. Yu and Koyama (1998) was found to perform well for CO2, 7 mm and smaller tubes and low helix angles (5° to 10°). Interestingly, Cavallini et al. (2009), Yu and Koyama (1998) and Chamra et al. (2005) were found to predict the HTC satisfactorily for zeotropic refrigerants such as R407C, although their development was based on pure and near-azeotropic refrigerants only. The Han and Lee (2005) correlation was found to be inaccurate over most of the data set and therefore has a very low probability of being recommended for any application.
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Reports on the topic "Zeotropic refrigerant"

1

Pannock, Jurgen, and David A. Didion. The performance of chlorine-free binary zeotropic refrigerant mixtures in a heat pump. Gaithersburg, MD: National Institute of Standards and Technology, 1991. http://dx.doi.org/10.6028/nist.ir.4748.

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2

Rothfleisch, Peter I. A simple method of composition shifting with a distillation column for a heat pump employing a zeotropic refrigerant mixture. Gaithersburg, MD: National Institute of Standards and Technology, 1995. http://dx.doi.org/10.6028/nist.ir.5689.

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3

Conklin, J., and J. Bogart. Final Report for Cooperative Research and Development Agreement (CRADA) Number ORNL95-0330, Heat Transfer Surface Augmentation for Zeotropic Mixture Alternatives to HCFC Refrigerants. Office of Scientific and Technical Information (OSTI), March 1997. http://dx.doi.org/10.2172/10141249.

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