Articoli di riviste: "OF THREE STAGE CASCADE REFRIGERATION SYSTEM"

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Sivakumar, Mayilsamy, e Periasamy Somasudaram. "Thermodynamic investigations of Zeotropic mixture of R290, R23 and R14 on three-stage auto refrigerating cascade system". Thermal Science 20, n. 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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Jemni, Nourheine, Mouna Elakhdar, Ezzedine Nehdi e Lakdar Kairouani. "Performance Investigation of Cascade Refrigeration System Using CO2 and Mixtures". International Journal of Air-Conditioning and Refrigeration 23, n. 03 (settembre 2015): 1550022. http://dx.doi.org/10.1142/s2010132515500224.

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This paper presents reports on simulation and comparative analysis of single stage vapor compression refrigeration system and cascade systems using carbon dioxide, hydrocarbons (HCs) and CO2/HCs mixture. Thermodynamic parameters of fluids are given using the software REFPROP 9.0. To select the most suitable HCs, three criteria have been fixed: Tc, Tt and Tb. It is found that the HCs chosen in low-stage are propane, propylene and ethane and those for the high-stage are propane, propylene and isobutane. The fraction mixture in the two loops has been varied and results are compared with single stage and cascade systems using CO2 and R22. The fraction x[Formula: see text] is varied in the two loops. Results are compared for single and cascade systems using CO2 and R22. For the single stage system, we find for xCO2 = 0.5, an improvement of COP of 14% for CO2/propane mixture and 36% for the CO2/propylene mixture. It is found that for xCO2 = 0.3, cascade system using propane/CO2 mixtures presents a COP lower than that of cascade system using pure CO2. About of 70% of unfriendly fluids like CFCs and HCFCs can be replaced with CO2, without affecting the performance of cascade refrigeration systems.

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RUCIŃSKI, Adam, Mateusz DALBA e Rafał LASKOWSKI. "Comparative analysis of a cooling systems working on an environmentally friendly refrigerants". Inżynieria Bezpieczeństwa Obiektów Antropogenicznych, n. 4 (19 dicembre 2021): 32–40. http://dx.doi.org/10.37105/iboa.123.

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The paper treats with refrigerants which affect on excessive heating of atmosphere. They are in group offluorinated greenhouse gases which are regulated by European and polish law. The main aim is to lower their amount in industry leading to overall removal from use. We present possible way to design refrigeration system lowering their adverse effect on natural environment. So three options of cooling systems are analyzed: one-stage refrigeration system working with R449A, cascade refrigeration system with R744 (carbon dioxide)/ R134a and R717 (ammonia) refrigeration plant. Due to the nowadays raising use of the cascade systems, an analysis of the operating parameters of such installation was carried out with considering the cascade heat exchanger as a condenser/evaporator. The installations concerned are three alternative offers for meat processing manufactory. A thermal balance was prepared for chambers located in building and the operating parameters of the installation were assumed. The equipment corresponding to the required cooling capacities were selected.

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Sun, Zhili, Qifan Wang, Baomin Dai, Meng Wang e Zhiyuan Xie. "Options of low Global Warming Potential refrigerant group for a three-stage cascade refrigeration system". International Journal of Refrigeration 100 (aprile 2019): 471–83. http://dx.doi.org/10.1016/j.ijrefrig.2018.12.019.

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Misra, R. S. "Performance Evaluation of Ecofriendly Refrigerants in the Low Temperature Circuit in Terms of First Law and Second Law Efficiency of Three Stages Cascade Vapour Compression Refrigeration of Biomedical Applications". International Journal of Advance Research and Innovation 3, n. 2 (2015): 141–50. http://dx.doi.org/10.51976/ijari.321530.

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Biomedical preservation requires storing biological specimens like stem cells blood and organs, at a storage temperature below -95oC. ,Hence, the main aim of the current research is to conduct a thermodynamic energy and exergy analysis to determine the thermal performance of three stages / four stages cascade refrigeration systems in the high temperature condenser temperature of 70oC using R1234ze and R1234yf in high temperature circuit and varying evaporator temperature (-20 oC to 10oC) in High temperature circuit, Varying evaporator temperature in first intermediate evaporator temperature (-70oC to -90oC) circuit using R134a and R410a as ecofriendly refrigerants is investigated. For low temperature evaporator temperature( -145oC to -100 oC) using hydrocarbons (R290, R600 and R600a) , R404a and other refrigerants in low temperature evaporator circuit on system performances (i.e. overall system coefficient of performance, (first law efficiency), exergetic efficiency (second law efficiency) and system exergy destruction ratio (EDR) is investigated in three stages /four stages cascade refrigeration systems are shown in this paper

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Qin, Yanbin, Nanxi Li, Hua Zhang e Baolin Liu. "Energy and exergy performance evaluation of a three-stage auto-cascade refrigeration system using low-GWP alternative refrigerants". International Journal of Refrigeration 126 (giugno 2021): 66–75. http://dx.doi.org/10.1016/j.ijrefrig.2021.01.028.

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AIKINS, KOJO ATTA, SANG-HYEOK LEE e JONG MIN CHOI. "TECHNOLOGY REVIEW OF TWO-STAGE VAPOR COMPRESSION HEAT PUMP SYSTEM". International Journal of Air-Conditioning and Refrigeration 21, n. 03 (settembre 2013): 1330002. http://dx.doi.org/10.1142/s2010132513300024.

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There is increasing demand for domestic and industrial refrigeration, space heating and air conditioning. Heat pump systems offer economical alternatives for recovering heat from different sources for use in these applications. As a renewable energy technology for sustainable environment, the heat pump's high efficiency and low environmental impact have already drawn a fair amount of attention all over the world. Some of these domestic and industrial applications require very low evaporating temperatures and very high condensing temperatures which induce high compressor pressure ratios beyond the practical range for single-stage heat pump cycles. These high pressure ratios also produce low coefficient of performance (COP) values and expose the compressor to high discharge temperature, low volumetric efficiency and damage. However, this challenge can be overcome by adopting two-stage heat pump cycles. In this paper, recent works on two-stage heat pump systems for various applications are reviewed. They include two-stage cycle with intercooling, two-stage cycle with refrigerant injection and two-stage cascade cycle. Research and innovative designs of systems that make use of these two-stage cycles have been able to get heat pumps to handle applications with lower and higher temperatures, while enhancing heating capacity up to 30% and COP up to 31%.

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Qin, Yanbin, Nanxi Li, Hua Zhang e Baolin Liu. "Thermodynamic performance of a modified −150 °C refrigeration system coupled with Linde-Hampson and three-stage auto-cascade using low-GWP refrigerants". Energy Conversion and Management 236 (maggio 2021): 114093. http://dx.doi.org/10.1016/j.enconman.2021.114093.

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Sivakumar, M., e P. Somasundaram. "Exergy and energy analysis of three stage auto refrigerating cascade system using Zeotropic mixture for sustainable development". Energy Conversion and Management 84 (agosto 2014): 589–96. http://dx.doi.org/10.1016/j.enconman.2014.04.076.

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Peng, Zeyu, Zeyu Li, Junquan Zeng e Jianting Yu. "Thermodynamic Study of Solar-Assisted Hybrid Cooling Systems with Consideration of Duration in Heat-Driven Processes". Energies 15, n. 10 (11 maggio 2022): 3533. http://dx.doi.org/10.3390/en15103533.

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Solar-assisted hybrid cooling systems are promising for the energy saving of refrigeration systems. In most cases, the solar thermal gain is only able to power the heat-driven process of facilities during part of the working period. Therefore, the reduction of compressor power strongly depends upon the duration of heat-driven processes, which has not been addressed properly. Motivated by such a knowledge gap, the thermodynamic understanding of solar-assisted hybrid cooling systems is deepened through considering the duration in heat-driven processes. Three absorption–compression-integrated cooling cycles were taken as examples. It was found that optimal parameters, e.g., inter-stage pressure and temperature, corresponding to various performance indicators tend to be identical, as the duration of heat-driven processes is taken into account. Furthermore, the optimal parameter for different working conditions was obtained. The dimensionless optimal intermediate temperature of layout with the cascade condensation process varies slightly, e.g., 4%, for different conditions. Moreover, the fall of compressor power in the entire working period was nearly independent upon the intermediate temperature. The paper is favorable for the efficient design and operation of solar-assisted hybrid cooling systems.

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He, Mingli. "A Study of Two Stage Cascade Refrigeration". World Journal of Educational Research 4, n. 2 (21 aprile 2017): 290. http://dx.doi.org/10.22158/wjer.v4n2p290.

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<em>This paper reports the feasibility study of building a cascade refrigeration system using commercially available “off the shelf” components. The unit is to be used by a residential home or a small business with common and less expensive refrigerants and components. The research was carried out as an undergraduate project. Topics involving advanced refrigeration system is an elective course at MSU Denver. Students who participated in this project have not taken such course yet. Just in time teaching in special topics enabled the students to study the cascade refrigeration system, refrigerants behavior and natural gas behavior in order to design and build the system. As project based learning and teaching have been recognized and adopted by more and more academic units, the presented project demonstrates that complex systems can be taught, learned, and built through a project based learning process.</em>

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Zheng, Da Yu, Dan Li, Jia Zheng, Li Ping Gao e Yi Ming Zhang. "The Study of the Effects of Refrigerant Fraction on Auto-Cascade Refrigeration System of Evaporation Temperature". Advanced Materials Research 889-890 (febbraio 2014): 321–24. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.321.

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Non-azeotropic auto-cascade refrigeration system utilizes various components of different boiling refrigerant to get low-temperature. With R22, R23 and R14 as a non-azeotropic refrigerant auto-cascade refrigeration cycle system. Through the experimental study of non-azeotropic refrigerant charging and the ratio between the amount of charge, to analyze the effect of these three refrigerants charging and relationship of the fraction on the whole refrigeration cycle refrigeration temperature. To improve overall non-azeotropic auto-cascade refrigeration systems working efficiency. So as to achieve the purpose of energy saving.

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Mohammadi, SM Hojjat, e Mehran Ameri. "Energy and exergy analysis of a two-stage cascade refrigeration system". Building Services Engineering Research and Technology 37, n. 4 (14 novembre 2015): 395–412. http://dx.doi.org/10.1177/0143624415615327.

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14

Zhao, Wei, Rui Xi Liu, Hai Dong Zhang, Hua Zhang e Shu Chun Zhang. "The Comparative Analysis of R22 and R134a Applied in a Five-Stage Auto-Cascade Refrigeration System". Applied Mechanics and Materials 291-294 (febbraio 2013): 1740–45. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.1740.

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The mixed refrigerants R22/R23/R14/R740/R728 and R134a/R23/R14/R740/R728 are used in a five-stage auto-cascade refrigeration system for study in this paper. Through theoretic comparison of high temperature stage refrigerant R22 and R134a and repeated experiments we can get the results that the discharge temperature of the refrigerant R134a can be effectively controlled and a lower refrigeration temperature can be got than the refrigerant R22.

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Shiba, T., K. Ito, R. Yokoyama, S. Sakashita e Y. Himura. "Optimal Planning of a Cascade-Type Multistage Refrigeration System for a Beverage Plant". Journal of Energy Resources Technology 121, n. 4 (1 dicembre 1999): 262–67. http://dx.doi.org/10.1115/1.2795992.

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An optimal planning method is presented for a cascade-type multistage refrigeration system. Heat exchange areas of evaporator, condenser, and beverage cooler are determined optimally so as to minimize the annual total cost and input energy consumption subject to constraints concerning annual equipment operation. This problem is considered as a multiobjective optimization one, and a discrete set of Pareto optimal solutions is derived numerically by a weighting method. Through a numerical study, it is investigated how the heat exchange areas influence the long-term economics and energy conservation. Cascade-type multistage refrigeration systems are compared with single-stage systems.

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Messineo, Antonio. "R744-R717 Cascade Refrigeration System: Performance Evaluation compared with a HFC Two-Stage System". Energy Procedia 14 (2012): 56–65. http://dx.doi.org/10.1016/j.egypro.2011.12.896.

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Sun, Zhili, Qi Cui, Qingzhao Liu, Caiyun Wang, Jiamei Li e Lijie Yang. "Energetic and economic analysis of vapour compression refrigeration systems applied in different temperature ranges". HKIE Transactions 27, n. 3 (30 ottobre 2020): 135–45. http://dx.doi.org/10.33430/v27n3thie-2018-0035.

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To determine the suitable vapour compression refrigeration system for different temperature ranges, this paper established thermodynamic models for a single-stage vapour compression refrigeration system with an economiser (SSRS+E), a two-stage vapour compression refrigeration system (TSRS), and a cascade vapour compression refrigeration system (CRS) and conducted an energetic and economic analysis of it. The results show that compared with TSRS, SSRS+E can save energy by 13.6% and 7.1%, in the evaporating temperatures of -20°C and -25°C, respectively. R744/R717 CRS is superior to TSRS in terms of energy consumption and refrigeration unit investment costs. Compared with TSRS, R744/R717 CRS can save energy by 14.1% and 18.8%, in the evaporating temperatures of -45°C and -50°C, respectively. Based on the energetic and economic analysis, SSRS+E is recommended for use above the evaporating temperature of -25°C. TSRS is recommended for use in the evaporating temperature range of -45°C to -25°C, and R744/R717 CRS is recommended for use below the evaporating temperature of -45°C.

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Catalán-Gil, Jesús, Daniel Sánchez, Rodrigo Llopis, Laura Nebot-Andrés e Ramón Cabello. "Energy Evaluation of Multiple Stage Commercial Refrigeration Architectures Adapted to F-Gas Regulation". Energies 11, n. 7 (23 luglio 2018): 1915. http://dx.doi.org/10.3390/en11071915.

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This work analyses different refrigeration architectures for commercial refrigeration providing service to medium and low temperature simultaneously: HFC/R744 cascade, R744 transcritical booster, R744 transcritical booster with parallel compression, R744 transcritical booster with gas ejectors, R513A cascade/R744 subcritical booster, and R513A cascade/R744 subcritical booster with parallel compression. The models were developed using compressor manufacturers’ data and real restrictions of each system component. Limitations and operating range of each component and architecture were analysed for environment temperatures from 0 to 40 °C considering thermal loads and environment temperature profiles for warm climates. For booster systems, cascade with subcritical booster with parallel compression provide highest coefficient of performance (COP) for temperatures below 12 °C and above 30 °C with COP increases compared basic booster up to 60.6%, whereas for transcritical boosters, architecture with gas ejectors obtains the highest COP with COP increases compared to the basic booster up to 29.5%. In annual energy terms, differences among improved booster systems are below 8% in the locations analysed. In Total Equivalent Warming Impact (TEWI) terms, booster architectures get the lowest values with small differences between improved boosters.

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MESSINEO, ANTONIO, e DOMENICO PANNO. "PERFORMANCE EVALUATION OF CASCADE REFRIGERATION SYSTEMS USING DIFFERENT REFRIGERANTS". International Journal of Air-Conditioning and Refrigeration 20, n. 03 (settembre 2012): 1250010. http://dx.doi.org/10.1142/s2010132512500101.

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Due to the negative effects of synthetic refrigerants on the environment, natural refrigerants have obtained again interest as alternative refrigerants for different applications because of their zero ODP and negligible GWP. This paper presents a thermodynamic analysis of different two-stage cascade refrigeration systems using as refrigerant carbon dioxide (R744) in low-temperature circuit, and, respectively, ammonia (R717), propane (R290), butane (R600), R404A, R410A and R134a in high-temperature circuit. The operating parameters considered in this study include condensing and evaporating temperatures in high-temperature circuit, temperature difference in the cascade heat exchanger, and evaporating and condensing temperatures in the low-temperature circuit. The results obtained show that a cascade refrigeration system using natural refrigerants is an interesting alternative to systems using synthetic refrigerants for energetic, security and environmental reasons.

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Sun, Zhili, Caiyun Wang, Youcai Liang, Huan Sun, Shengchun Liu e Baomin Dai. "Theoretical study on a novel CO2 Two-stage compression refrigeration system with parallel compression and solar absorption partial cascade refrigeration system". Energy Conversion and Management 204 (gennaio 2020): 112278. http://dx.doi.org/10.1016/j.enconman.2019.112278.

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Sun, Xiaojing, Linlin Liu, Yu Zhuang, Lei Zhang e Jian Du. "Heat Exchanger Network Synthesis Integrated with Compression–Absorption Cascade Refrigeration System". Processes 8, n. 2 (9 febbraio 2020): 210. http://dx.doi.org/10.3390/pr8020210.

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Compression–absorption cascade refrigeration system (CACRS) is the extension of absorption refrigeration system, which can be utilized to recover excess heat of heat exchanger networks (HENs) and compensate refrigeration demand. In this work, a stage-wise superstructure is presented to integrate the generation and evaporation processes of CACRS within HEN, where the generator is driven by hot process streams, and the evaporation processes provide cooling energy to HEN. Considering that the operating condition of CACRS has significant effect on the coefficient of performance (COP) of CACRS and so do the structure of HEN, CACRS and HEN are considered as a whole system in this study, where the operating condition and performance of CACRS and the structure of HEN are optimized simultaneously. The quantitative relationship between COP and operating variables of CACRS is determined by process simulation and data fitting. To accomplish the optimal design purpose, a mixed integer non-linear programming (MINLP) model is formulated according to the proposed superstructure, with the objective of minimizing total annual cost (TAC). At last, two case studies are presented to demonstrate that desired HEN can be achieved by applying the proposed method, and the results show that the integrated HEN-CACRS system is capable to utilize energy reasonably and reduce the total annualized cost by 38.6% and 37.9% respectively since it could recover waste heat from hot process stream to produce the cooling energy required by the system.

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Benbia, Leila, Saida Fedali, Cherif Bougriou e Hakim Madani. "Influence of azeotropic binary mixtures on single-stage refrigeration system performance". High Temperatures-High Pressures 51, n. 4 (2022): 319–39. http://dx.doi.org/10.32908/hthp.v51.1185.

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The current study concerns the use of azeotropic mixtures in single-stage vapor compression refrigeration system configurations to determine the effect of entrainment ratio on the coefficient of performance. Three singlestage vapor compression refrigeration system configurations are used. The effects of condenser and evaporator temperatures on the single-stage refrigeration system are investigated. The used azeotropic mixtures are: R1234yf + R290, R1234yf + R152a, R1234yf + R600a, R134a + R290, R134a + R600a and R1270 + R134a. It is shown that the simulations results are in good agreement with the literature. The R1234yf + R290 mixture in refrigeration cycle give the highest coefficient of performance and entrainment ratio. The coefficient of performance (COP) increases with increasing of entrainment ratio.

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A. S., Ipinmoroti, e Oluwaleye I.O. "Development and Performance Evaluation of a Two-Stage Cascade Refrigeration System for Ice Block Production". Asian Journal of Applied Science and Technology 04, n. 01 (2020): 81–97. http://dx.doi.org/10.38177/ajast.2020.4108.

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Mishra, Radhey Shyam. "Optimization of Two-Stage Cascade Refrigeration Systems Using Hfo Refrigerants in The High-Temperature Circuit and Hfc-134a in Low-Temperature Circuit". International Journal of Advance Research and Innovation 6, n. 4 (2018): 82–106. http://dx.doi.org/10.51976/ijari.641811.

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The eco-friendly refrigeration technologies which are receiving more and more attention in the days by day of for solving energy and environmental problems. In this paper, it is suggested to phase out presently most used refrigerant R-134a considering global warming and to use natural refrigerants such as ammonia, carbon dioxide and hydro carbons in two stage cascade vapour compression refrigeration system for sustainable environment. Thermal model was developed for single stage and also two stage cascade refrigeration systems using HFO-1234yf for low temperature applications in the range of 100°C to -51.5°C and HFO-1234ze for high temperature applications in the range of 100°C to -30.5°C. Numerical computation was carried out by using R1234ze in the temperature range of 60°Cto -30°Cin the high temperature circuit and R1234yf in the range of 20°Cto -50°Cfor low temperature range. The developed model can also predicts the thermal performances of using nine eco-friendly refrigerants in low temperature circuit and R1234ze n low temperature applications. The ecofriendly refrigerants HFO can replace R134a without minor modifications. However up to temperature -50°Cin the low temperature evaporator circuit with temperature overlapping (Approach=10oC) and condenser temperature of 55°Cwith cascade evaporator temperature of 0°C , the combination of R1234ze in high temperature circuit and R1234yf in low temperature circuit gives best results for replacing R134a and for -100°Cof low temperature evaporator circuit and 55°Cof high temperature condenser and -30°C cascade evaporator with temperature overlapping (Approach=10oC) the combination of R1234ze – and R245fa gives better thermodynamic performances as compared to R-1234yf and R245fa. The optimum values for system-6 (using R1234ze in high temperature circuit and HFC-134a in low temperature circuit , the optimum second law efficiency (exergetic efficiency) obtained at low temperature evaporator is at -78°Cto -80°Crespectively and no optimum was found using HFO-1234yf in high temperature circuit and HFC-134a in low temperature circuit.

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Nickl, J., G. Will, H. Quack e W. E. Kraus. "Integration of a three-stage expander into a CO2 refrigeration system". International Journal of Refrigeration 28, n. 8 (dicembre 2005): 1219–24. http://dx.doi.org/10.1016/j.ijrefrig.2005.08.012.

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Porutchikov, Artem Frolovich, e Dmitriy Pavlovich Trubin. "Low temperature vacuum sublimation refrigerators on carbon dioxide as working fluid". MATEC Web of Conferences 324 (2020): 02004. http://dx.doi.org/10.1051/matecconf/202032402004.

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The paper presents the results of theoretical and experimental analysis of a vacuum-freeze-drying refrigeration machine based on carbon dioxide. Such refrigeration machines can be equipped with refrigerators for the needs of medicine, where low temperatures are widely in demand in the range from minus 80 degrees Celsius to minus 130 degrees Celsius. The problem of developing alternative refrigeration machines is dictated by modern environmental requirements for working substances, which are gradually being tightened and soon the use of familiar freons will become impossible. For the air conditioning and commercial refrigeration industry, new substances are being actively developed, such as hydrofluoroolefins (HFOs), hydrocarbons can also serve as substitutes for hydrofluorocarbons and their mixtures, but it must be considered that they are combustible and explosive. A carbon dioxide vacuum sublimation unit may be an alternative to modern freon vapor compression refrigeration units for the indicated temperature range, but subject to comparable energy costs during its operation. The article examined the three-stage and four-stage cycles of a vacuum-freeze-drying refrigeration machine, conducted their theoretical comparison in terms of COP with a cascade cycle on hydrocarbon working substances. It can be noted that the COP of the considered cycles are close, but the environmental friendliness, safety and non-combustibility of carbon dioxide gives the advantages of a vacuum freeze-drying refrigeration machine.

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Xu, Likang, e Guihua Lin. "Simulation and optimization of liquefied natural gas cold energy power generation system on floating storage and regasification unit". Thermal Science, n. 00 (2020): 205. http://dx.doi.org/10.2298/tsci200404205x.

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In this paper, based on the idea of reducing heat exchanger exergy destruction and increasing turbine work, a new three-stage cascade Rankine system and a new four-stage cascade Rankine system is proposed to improve the cold energy utilization rate during liquefied natural gas(LNG) gasification on liquefied natural gas-floating storage and regasification unit. Then compare them with the original cascade Rankine cycle established under the same conditions. The results show that under the condition of 175 t/h LNG flow, the maximum net output power of the new three-stage cascade Rankine cycle system is 4593.31 kW, the exergy efficiency is 20.644%. The maximum net output power of the new four-stage cascade Rankine cycle system is 5013.93 kW, and the exergy efficiency is 22.509%. Compared with the original cascade Rankine cycle system, the maximum net output power of the new three-stage cascade Rankine cycle system and the new four-stage cascade Rankine cycle system is increased by 9.41% and 11.45%, respectively, and the system exergy efficiency is increased by 9.29% and 11.28%, respectively.

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Qin, Yanbin, Nanxi Li, Hua Zhang, Binhui Jin e Baolin Liu. "Experimental characterization of an innovative refrigeration system coupled with Linde-Hampson cycle and auto-cascade cycle for multi-stage refrigeration temperature applications". Energy 240 (febbraio 2022): 122498. http://dx.doi.org/10.1016/j.energy.2021.122498.

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Jung, Il Young, Kyung Rok Mun e Sang Kook Yun. "Study on the Performance of New Two-Stage Expansion Auto-Cascade Refrigeration System with CO₂-R134a Mixed Refrigerants". Korean Journal of Air-Conditioning and Refrigeration Engineering 30, n. 11 (30 novembre 2018): 526–32. http://dx.doi.org/10.6110/kjacr.2018.30.11.526.

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Garcíadealva, Yeudiel, Roberto Best, Víctor Hugo Gómez, Alejandro Vargas, Wilfrido Rivera e José Camilo Jiménez-García. "A Cascade Proportional Integral Derivative Control for a Plate-Heat-Exchanger-Based Solar Absorption Cooling System". Energies 14, n. 13 (5 luglio 2021): 4058. http://dx.doi.org/10.3390/en14134058.

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Automatic proportional integral derivative control techniques are applied in a single-stage solar absorption cooling system, showing 3.8 kW (~1 ton) cooling capacity, with a coefficient of performance of 0.6 and −4.1 °C evaporator cooling temperature. It is built with plate heat exchangers as main components, using ammonia–water as the working mixture fluid and solar collectors as the main source of hot water. Control tuning was verified with a dynamical simulation model for a solution regarding mass flow stability and temperature control in the solar absorption cooling system. The controller improved steady thermodynamic state and time response. According to experimental cooling temperatures, the system could work in ranges of refrigeration or air-conditioning end-uses, whose operation makes this control technique an attractive option to be implemented in the solar absorption cooling system.

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Baiju, V., e C. Muraleedharan. "Exergy Assessment of Single Stage Solar Adsorption Refrigeration System Using ANN". ISRN Mechanical Engineering 2012 (25 settembre 2012): 1–10. http://dx.doi.org/10.5402/2012/915154.

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A new approach based on artificial intelligence is proposed here for the exergy assessment of solar adsorption refrigeration system working with activated carbon-methanol pair. Artificial neural network model is used for the prediction of exergy destruction and exergy efficiency of each component of the system. Pressure, temperature and solar insolation are used as input variables for developing the artificial neural network model. The back propagation algorithm with three different variants such as CGP, SCG and LM are used in the network A and network B. The most suitable algorithm and the number of neurons in hidden layer are found as LM with 9 for network A and SCG with 17 for the Network B. The artificial neural network predicted results are compared with the calculated values of exergy destruction and exergy efficiency. The values of the exergy destruction and exergy efficiency of components (condenser, expansion device, evaporator, adsorbent bed, solar concentrator and overall system) are found to be close to 1. The RMS and COV values are found to be very low in all cases. The comparison of the results suggests that the artificial neural network provided results are within the acceptable range.

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32

Yalama, Viktor, Olga Yakovleva, Volodymyr Trandafilov e Mykhailo Khmelniuk. "Future Sustainable Maritime Sector: Energy Efficiency Improvement and Environmental Impact Reduction for Fishing Carriers Older than 20 Years in the Fleet Part II". Polish Maritime Research 29, n. 3 (1 settembre 2022): 78–88. http://dx.doi.org/10.2478/pomr-2022-0028.

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Abstract (sommario):

Abstract For the maritime sector to be sustainable and to have an intact blue economy, shipowners should be ready to implement Ship Energy Efficiency Management Plans alongside energy efficiency projects. The problem for organizations and shipowners having fishing carriers older than 20 years is highlighted and the following challenges arise for decision-making authorities. To keep such ships in the fleet for the next decade, shipowners should deploy energy efficiency projects for marine system retrofitting to improve energy efficiency and meet environmental regulations. An energy audit is performed and an energy efficiency program is proposed with guidelines for regulations that are currently coming into force. To improve energy efficiency, reduce the environmental impact, and cut fuel consumption costs, marine system retrofitting is done, in a particular case, with two options proposed. The first is a cascade refrigeration system with hydrocarbons and carbon dioxide, where the shipowner gains an energy efficiency improvement of about 20%. The second option is a two-stage refrigeration system with ammonium as the environmentally friendly refrigerant, which improves the energy efficiency by about 26%. Technical and economic issues have been discussed.

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33

Sokolovska-Yefymenko, Viktoriia, Larisa Morozyuk, Volodymyr Ierin e Oleksandr Yefymenko. "Thermodynamic Analysis of an Ethylene Reliquefaction System Using the Entropy-Cycle Method". Energies 16, n. 2 (13 gennaio 2023): 920. http://dx.doi.org/10.3390/en16020920.

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In this study, a boil-off gas reliquefaction system that is a part of liquid ethylene gas (LEG) carriers is evaluated. The reliquefaction system is formed by two thermally interconnected two-stage refrigeration cycles. The working fluid of the bottoming cycle is ethylene; the working fluid of the topping cycle is propylene. The research is based on determining the irreversibilities in the reliquefaction system cycles using the entropy-cycle method of thermodynamic analysis. The impact of the process performance in the main components on the reliquefaction system energy efficiency has been evaluated by the entropy-cycle method. The greatest thermodynamic irreversibility is observed in the two-stage compression process of the bottoming cycle (9%), total throttling irreversibility in the reliquefaction system (8.5%), and vapor superheating at the suction into the low stage of the two-stage compressor of the bottoming cycle (8%). The results of the study showed that it is necessary to improve the design of expansion devices using the replacement of throttle devices with ejectors when designing cascade ethylene reliquefaction plants. In addition, when operating such systems much attention should be paid to the condition of the insulation of cargo pipelines and the parameters of the cooling system of the cargo compressor.

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Drojetzki, Lawrence, e Mieczyslaw Porowski. "Outdoor Climate as a Decision Variable in the Selection of an Energy-Optimal Refrigeration System Based on Natural Refrigerants for a Supermarket". Energies 16, n. 8 (12 aprile 2023): 3375. http://dx.doi.org/10.3390/en16083375.

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This paper presents the results of a simulation study on the selection of an energy-optimal refrigeration system based on natural refrigerants as a function of outdoor climate parameters as a decision variable in a supermarket application. Simulations were conducted for twelve locations. Three new original refrigeration systems were presented: Cascade R744/R717 which is an advanced booster extended with an ammonia condensing system (CASC_1); Cascade R744/R717 with CO2 pump-fed MT and pressure-fed LT evaporators (CASC_2); and the R717 booster with CO2 pump-fed MT and LT evaporators (CB_NH3). As a reference system, a CO2 booster system with multi-ejectors and flooded evaporators (CB_EJ) was adopted. The CB_EJ system has been confirmed to be energy optimal for cold and temperate climates (Cfb, Dfa and cooler). In warm temperate climates (Csa, BSk, Cfa and similar), the energy consumption of CB_NH3 was the lowest. CASC_2 and CB_NH3 are energy optimal for hot climates (BWh, Af, Aw). The CB_NH3 system always outperforms CASC_2 by 2.5–3.8%. For a tropical climate (Bhubaneswar—Aw), the annual electricity demand of the optimal CB_NH3 system is lower by 18.8%, 10.2%, and 2.7% relative to CB_EJ, CASC_1, and CASC_2, respectively. The COP of the CASC_1 (outdoor temperature 40 °C) is higher by 50%, 2.7%, and 4.7% compared with the CB_EJ, CB_NH3 and CASC_2 systems, respectively. The application of CASC_1 system, relative to CB_EJ, is reasonable only for hot climates and decreases by 7.2% the annual electricity demand for Bhubaneswar.

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35

Misra, R. S. "Use of Hydrocarbons in Low Temperature Circuit in Terms of First Law and Second Law Efficiency of Four Stage Cascade Refrigeration of Semen Preservation". International Journal of Advance Research and Innovation 2, n. 4 (2014): 104–12. http://dx.doi.org/10.51976/ijari.241415.

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Abstract (sommario):

This paper mainly deals with the utility of hydrocarbons , R404a and other ecofriendly refrigerants in the low temperature circuit for semen preservation. The energy-exergy analysis have been carried out to find out the feasibility of above ecofriendly refrigerants in the Four stage cascade refrigeration system using R1234ze in high temperature circuit and R134a in primary intermediate circuit and R410a in secondary intermediate circuit. It was observed that the use of hydrocarbon is feasible for improving thermal performance of the above system by considering safety measures. The best second law performance was observed using R600a and low performance was observed using ethylene in the low temperature evaporator circuit without safety measure the system using R404a in low temperature evaporator circuit gives better performance using ethylene in low temperature circuit.

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36

Sun, Heng, Hong Mei Zhu e Hong Wei Liu. "Process Simulations of the Cold Recovery Unit in a LNG CCHP System with Different Power Cycles". Applied Mechanics and Materials 90-93 (settembre 2011): 3026–32. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.3026.

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Abstract (sommario):

A CCHP system using LNG as the primary energy should integrate cold recovery unit to increase the total energy efficiency. A scheme of CCHP consisting of gas turbine-steam turbine combined cycle, absorption refrigeration unit, cold recovery unit and cooling media system is a system with high efficiency and operation flexibility. Three different power cycles using the cold energy of LNG is(are 或 were) presented and simulated. The results show that the cascade Rankine power cycle using ethylene and propane in the two cycles respectively has highest energy efficiency. However, the unit is most complex. The efficiency of ethylene Rankine power cycle is little lower than the cascade one, and is much higher than the traditional propane Rankine cycle. The complexity of ethylene cycle is identical to that of the propane cycle. The ethylene Rankine power cycle is the referred method of cold recovery in a CCHP system based on overall considerations.

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37

Ghanbarpour, Morteza, Adrián Mota-Babiloni, Bassam E. Badran e Rahmatollah Khodabandeh. "Energy, Exergy, and Environmental (3E) Analysis of Hydrocarbons as Low GWP Alternatives to R134a in Vapor Compression Refrigeration Configurations". Applied Sciences 11, n. 13 (5 luglio 2021): 6226. http://dx.doi.org/10.3390/app11136226.

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The phase-down of hydrofluorocarbons and substitution with low global warming potential values are consequences of the awareness about the environmental impacts of greenhouse gases. This theoretical study evaluated the energy and exergy performances and the environmental impact of three vapor compression system configurations operating with the hydrocarbons R290, R600a, and R1270 as alternatives to R134a. The refrigeration cycle configurations investigated in this study include a single-stage cycle, a cycle equipped with an internal heat exchanger, and a two-stage cycle with vapor injection. According to the results, the alternative hydrocarbon refrigerants could provide comparable system performance to R134a. The analysis results also revealed that using an internal heat exchanger or a flash tank vapor injection could improve the system’s efficiency while decreasing the heating capacity. The most efficient configuration was the two-stage refrigeration cycle with vapor injection, as revealed by the exergy analysis. The environmental impact analysis indicated that the utilization of environmentally-friendly refrigerants and improving the refrigeration system’s efficiency could mitigate equivalent CO2 emissions significantly. The utilization of hydrocarbons reduced the carbon footprint by 50%, while a 1% to 8% reduction could be achieved using the internal heat exchanger and flash tank vapor injection.

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38

Sun, Heng, Hong Mei Zhu e Dan Shu. "A LNG Driven CCHP System with a Cold Energy Recovery Device". Applied Mechanics and Materials 71-78 (luglio 2011): 1769–75. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.1769.

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Abstract (sommario):

The CCHP system based on energy cascade utilization can get very high energy overall utilization efficiency. When LNG is used as the primary energy of a CCHP system, the higher efficiency can be obtained if the cold energy of LNG is recovered. Three CCHP systems integrated with LNG cold recovery facility are presented which are suitable for different situations. The thermodynamic calculation and analysis of the system consisting of combined cycle generating electricity, the LiBr absorption refrigeration units, the cryogenic Rankine cycle generation system and the cooling medium system were carried out. The results showed that the energy utility efficiency of the electricity generating was 34.78% and the total energy utility efficiency was up to 86.49%. This indicates that this technology have the potential to be employed in the industrial applications.

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Mohammadi, S. M. Hojjat, e Mehran Ameri. "Energy and exergy performance comparison of different configurations of an absorption-two-stage compression cascade refrigeration system with carbon dioxide refrigerant". Applied Thermal Engineering 104 (luglio 2016): 104–20. http://dx.doi.org/10.1016/j.applthermaleng.2016.05.051.

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40

Baiju, V., e C. Muraleedharan. "Performance Prediction of Solar Adsorption Refrigeration System by Ann". ISRN Thermodynamics 2012 (7 marzo 2012): 1–8. http://dx.doi.org/10.5402/2012/102376.

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Abstract (sommario):

This paper proposes a new approach for the performance analysis of a single-stage solar adsorption refrigeration system with activated carbon-R134a as working pair. Use of artificial neural network has been proposed to determine the performance parameters of the system, namely, coefficient of performance, specific cooling power, adsorbent bed (thermal compressor) discharge temperature, and solar cooling coefficient of performance. The ANN used in the performance prediction was made in MATLAB (version 7.8) environment using neural network tool box.In this study the temperature, pressure, and solar insolation are used in input layer. The back propagation algorithm with three different variants namely Scaled conjugate gradient, Pola-Ribiere conjugate gradient, and Levenberg-Marquardt (LM) and logistic sigmoid transfer function were used, so that the best approach could be found. After training, it was found that LM algorithm with 9 neurons is most suitable for modeling solar adsorption refrigeration system. The ANN predictions of performance parameters agree well with experimental values with R2 values close to 1 and maximum percentage of error less than 5%. The RMS and covariance values are also found to be within the acceptable limits.

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41

Hao, Yan, Che Jun e Chen Siyu. "One-dimensional and three-dimensional coupling simulation research of centrifugal cascade hydraulics". Kerntechnik 87, n. 2 (14 febbraio 2022): 176–86. http://dx.doi.org/10.1515/kern-2021-0035.

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Abstract Centrifuge cascade hydraulics research is very important for the cascade system design and safety analysis. The one-dimensional centrifugal cascade dynamic hydraulics calculation program can be used to achieve the rapid verification of the cascade system dynamic operation or accident condition. While the computational fluid dynamics (CFD) program is mainly used to analyze the local three-dimensional fluid phenomena such as the centrifugal cascade pipe and equipment. To comprehensively utilize the advantages of the two simulation methods, based on the one-dimensional calculation software SimuWorks of centrifugal cascade hydraulics and three-dimensional flow field calculation software Fluent, a one-dimensional and three-dimensional coupling simulation program for centrifugal cascade hydraulics was developed by using the API functions provided by SimuWorks simulation software and the user-defined function (UDF) of Fluent. The coupling method is used to analyze the movement of solid particles in the main feed pipe of the separation stage. By comparing the calculation results of the coupling program with the calculation results of the traditional one-dimensional dynamic hydraulics program, it can be seen that the coupling program can correctly predict the influence of feeding orifice plate clogging on the system parameters and can more intuitively show the flow field characteristics in the important parts of the system. The motion characteristics of the solid particles obtained in the simulation verification are consistent with the experimental analysis results, which further verifies the accuracy of the coupling program. The coupling program can provide a new calculation method and analytical tool for the study of centrifugal cascade hydraulics.

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42

Yu, Yehong, Chen Lu, Sheng Ye, Zhengli Hua e Chaohua Gu. "Optimization on volume ratio of three-stage cascade storage system in hydrogen refueling stations". International Journal of Hydrogen Energy 47, n. 27 (marzo 2022): 13430–41. http://dx.doi.org/10.1016/j.ijhydene.2022.02.086.

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43

Keshtkar, Mohammad Mehdi. "Effect of subcooling and superheating on performance of a cascade refrigeration system with considering thermo- economic analysis and multi-objective optimization". Journal of Advanced Computer Science & Technology 5, n. 2 (19 luglio 2016): 42. http://dx.doi.org/10.14419/jacst.v5i2.6217.

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In present work, effect of degrees of subcooling and superheating based on thermoeconomic optimization is investigated in two stage-cascade refrigeration system (TS-CRS). At the first step, by using R717 and R744 as refrigerants, a thermoeconomic analysis is applied to TS-CRS. Based on results of the first section and using the genetic algorithm (GA) optimizer implemented in MATLAB, the optimum operative conditions of a specific TS-CRS is determined. Finally, based on the Pareto frontier obtained from the GA optimization, a decision-making strategy is then used to determine a final solution by TOPSIS method. Two single-objective optimization strategies (SOS), i.e. exergetic optimization and cost optimization, are applied on TS-CRS. The aim of the first strategy is to maximize the exergetic efficiency and the aim of the second strategy is minimizing the total annual cost of the system. The case study results show that, compared to the base design, the use of SOS for maximizing of exergetic efficiency can be increases the exergetic efficiency 94.5%. In addition, the use of the second SOS can decrease the total system cost by 11%. Using MOS compared to base design, exergetic efficiency and the total system cost can be increase by 99.1% and 28.6% respectively.

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44

Mancuhan, Ebru. "Comparative evaluation of a two-stage refrigeration system with flash intercooling using different refrigerants". Thermal Science 24, n. 2 Part A (2020): 815–30. http://dx.doi.org/10.2298/tsci180921011m.

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Abstract (sommario):

The aim of this study is to investigate the effect of low global warming potential refrigerants on the optimum intermediate pressure (POPT,int) and performance (COP) values of a refrigeration system with flash intercooling. For realize, the optimum operating parameters of system were determined in low temperature applications through a theoretical analysis according to the different refrigerants (R290, R404A, R407C, R507A, and R22). The theoretical modelling of system is done by optimizing the intermediate pressure at given evaporation (TE) and condensation (TC) temperatures for selected refrigerants. After optimization, the maximized values of COP and Second law efficiency are computed from the predicted values of POPT,int . The linear regression method is then used to derive three correlations of POPT,int , maximum values of COP and Second law efficiency according to TE and TC. Hence, the POPT,int values maximizing the system performance are found from various TE and TC values for each refrigerant. Due to calculations, increasing TE and TC cause the increase in POPT,int in low temperature applications. The R507A system has the highest POPT,int values and R22 system has the lowest POPT?int values. Although R22 system has slightly more efficient than R290 system, it is being phased out world?wide because of the risk of ozone depletion potential and global warming potential considerations. Therefore, it is important to evaluate the R22 replacement options. The R290 was discovered to have better performance than the R404A, R407C and R507A systems in terms of COPmax (1.81), global warming potential (11), and ozone depletion potential (0) when TE and TC are -35?C and 40?C.

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45

Misra, R. S. "Performance Optimization of Four Stage Cascade Refrigeration Systems using Energy-Exergy Analysis in the R1234ze R1234yf in High Temperature Circuitand Ecofriendly Refrigerants in Intermediate Ciircuits and Ethane in the Low Temperature Circuit for Food",. International Journal of Advance Research and Innovation 2, n. 4 (2014): 64–76. http://dx.doi.org/10.51976/ijari.241411.

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Abstract (sommario):

This paper mainly deals with the exergy analysis of Four stages cascade refrigeration systems used for low temperature applications using ecofriendly refrigerants. The effect of performance parameters (i.e. approaches, condenser temperature, and temperature variations in the evaporators) on the thermal performances in terms of second law efficiency of the system (exergetic efficiency) and exergy destruction ratio (EDR) and first law efficiency (i.e. overall coefficient of performance) have been optimized thermodynamically using of R1234yf and R1234ze in the high temperature circuits and mainly thirteen ecofriendly refrigerants in the intermediates circuits and ethane It was observed that in the low temperature (between- 80 oC to -88 oC) applications. It was observed that the best combination in terms of R1234ze-R134a-R410a-ethane gives better thermal performance than using R1234yf-R134a-R410a-ethane.

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46

Gil, Bartosz, Anna Szczepanowska e Sabina Rosiek. "New HFC/HFO Blends as Refrigerants for the Vapor-Compression Refrigeration System (VCRS)". Energies 14, n. 4 (11 febbraio 2021): 946. http://dx.doi.org/10.3390/en14040946.

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In this work, which is related to the current European Parliament Regulation on restrictions affecting refrigeration, four new three-component refrigerants have been proposed; all were created using low Global Warming Potential(GWP) synthetic and natural refrigerants. The considered mixtures consisted of R32, R41, R161, R152a, R1234ze (E), R1234yf, R1243zf, and RE170. These mixtures were theoretically tested with a 10% step in mass fraction using a triangular design. The analysis covered two theoretical cooling cycles at evaporating temperatures of 0 and −30 °C, and a 30 °C constant condensing temperature. The final stage of the work was the determination of the best mixture compositions by thermodynamic and operational parameters. R1234yf–R152a–RE170 with a weight share of 0.1/0.5/0.4 was determined to be the optimal mixture for potentially replacing the existing refrigerants.

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47

Hu, Yiwei, Xin Wang, Zhanghua Wu, Limin Zhang, Geng Chen, Jingyuan Xu e Ercang Luo. "A thermoacoustic cooler with a bypass expansion for distributed-temperature heat loads". Applied Physics Letters 121, n. 20 (14 novembre 2022): 203905. http://dx.doi.org/10.1063/5.0125314.

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In the context of the current energy crisis, a compact, simple, and reliable cooler is required at small-scale natural gas liquefaction stations. In this paper, a thermoacoustic cooler with a bypass expansion cooling for distributed-temperature heat loads is proposed. The bypass expansion configuration is used to carry out multiple refrigeration processes to achieve distributed cooling temperatures, thus realizing the cascade processes of natural gas liquefaction and improving the liquefaction efficiency. Simulations were carried out to investigate the effect of cooling-stage numbers on relative power consumption efficiency, exergy losses of components as well as axial distributions of key parameters. A proof-of-concept porotype of a two-stage thermoacoustic cooler was built, and the feasibility of the distributed heat loads was experimentally tested. Comparisons with a conventional single-stage thermoacoustic cooler without bypass expansion indicate that the proposed bypass expansion system improves the liquefaction cooling efficiency by a factor of 3.28 at 120 K. Experiments were also carried out to investigate the effect of the bypass expansion, an important factor, by verifying the total number of bypass orifices. Results show that increasing the number of bypass orifices with a more uniform gas distribution can improve the cooling performance of the system. The findings demonstrate the promising prospects of the proposed thermoacoustic cooler in the field of natural gas liquefaction.

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48

Bouaziz, Nahla, R. Ben Iffa, Lakdar Kairouani, Salahs Chikh e Rachid Bennacer. "Performance of a Water Ammonia Absorption System Operating at Three Pressure Levels". Defect and Diffusion Forum 312-315 (aprile 2011): 947–52. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.947.

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Abstract (sommario):

The present study deals with a compression-absorption machine. The proposed hybrid cooling system uses water-ammonia as a working fluid and operates at three pressure levels. The absorber is at an intermediate pressure (Pint) taken between the evaporator pressure (PEV) and the condenser pressure (PCD), unlike the single stage machine which works between two pressure levels. The proposed new system is studied and compared to the conventional machine. In order to evaluate the performance of the invoked machine, a procedure based on the MAPLE software is set up to compute accurately the thermodynamic properties of the working fluid. The analyses of the numerical results highlight that the performance of the novel proposed configuration is better than that relative to the conventional system. The study reveals the great impact of the intermediate pressure on the performance improvement and on reducing the generator temperature allowing the system to work at low enthalpy. In fact, for an evaporator temperature and a condenser temperature fixed respectively at -10°C and 40°C, the proposed hybrid refrigeration cycle operates at a generator temperature TGE = 75°C and the installation’s COP is about 0.56. While for the same conditions, the single stage machine COP cannot exceed 0.51 with a generator temperature of about 135°C. Consequently, our enhanced novel configuration presents the opportunity to operate at low enthalpy sources.

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Xu, Hao, Xiaotong Xi, Xiafan Xu, Jia Guo, Liubiao Chen, Wei Ji e Junjie Wang. "Development of a volatile organic compounds cryogenic condensation recovery system cooled by liquid nitrogen". IOP Conference Series: Materials Science and Engineering 1240, n. 1 (1 maggio 2022): 012098. http://dx.doi.org/10.1088/1757-899x/1240/1/012098.

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Abstract (sommario):

Abstract Volatile organic compounds (VOCs) are important precursors of ozone and PM2.5, and the reduction of VOCs emission is a key to control ozone and PM2.5 pollutions. For high-value VOCs such as oil gas, the cryogenic condensation method based on liquid nitrogen cooling is an effective way to recover VOCs. This method can achieve a refrigeration temperature of -170°C or even lower so that the treated exhaust gas concentration can satisfy the emission standard. In this paper, a thermodynamic model is established to calculate and analyze a designed three-stage condensation recovery VOCs system process based on liquid nitrogen cooling. A set of experimental equipment was further developed and tested. And the system process, calculation results, and experimental results are introduced.

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50

Ahmed, Rasel, Shuhaimi Mahadzir, Adrián Mota-Babiloni, Md Al-Amin, Abdullah Yousuf Usmani, Zaid Ashraf Rana, Hayati Yassin, Saboor Shaik e Fayaz Hussain. "4E analysis of a two-stage refrigeration system through surrogate models based on response surface methods and hybrid grey wolf optimizer". PLOS ONE 18, n. 2 (3 febbraio 2023): e0272160. http://dx.doi.org/10.1371/journal.pone.0272160.

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Abstract (sommario):

Refrigeration systems are complex, non-linear, multi-modal, and multi-dimensional. However, traditional methods are based on a trial and error process to optimize these systems, and a global optimum operating point cannot be guaranteed. Therefore, this work aims to study a two-stage vapor compression refrigeration system (VCRS) through a novel and robust hybrid multi-objective grey wolf optimizer (HMOGWO) algorithm. The system is modeled using response surface methods (RSM) to investigate the impacts of design variables on the set responses. Firstly, the interaction between the system components and their cycle behavior is analyzed by building four surrogate models using RSM. The model fit statistics indicate that they are statistically significant and agree with the design data. Three conflicting scenarios in bi-objective optimization are built focusing on the overall system following the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Linear Programming Technique for Multidimensional Analysis of Preference (LINMAP) decision-making methods. The optimal solutions indicate that for the first to third scenarios, the exergetic efficiency (EE) and capital expenditure (CAPEX) are optimized by 33.4% and 7.5%, and the EE and operational expenditure (OPEX) are improved by 27.4% and 19.0%. The EE and global warming potential (GWP) are also optimized by 27.2% and 19.1%, where the proposed HMOGWO outperforms the MOGWO and NSGA-II. Finally, the K-means clustering technique is applied for Pareto characterization. Based on the research outcomes, the combined RSM and HMOGWO techniques have proved an excellent solution to simulate and optimize two-stage VCRS.

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