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Journal articles on the topic 'Refrigeration compressor'
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1
Ali Al-Dabbas, Mohammad Awwad. "The Functioning of The Hybrid Integrated Partially Solar-Vapor-Compression Fridge." WSEAS TRANSACTIONS ON FLUID MECHANICS 16 (July 27, 2021): 141–57. http://dx.doi.org/10.37394/232013.2021.16.14.
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The main purpose of our research is to increase the utilization of solar thermal energy to supply a refrigerator with vapor compression and reduce the refrigeration power needed for cooling. Combined Hybrid Solar - the vapor- compression refrigerating unit has been built and operates under Mutah University's environment in Jordan. The systems were made up of a capillary tube, condenser, evaporator, and collector. The vapor-pressure refrigerator was incorporated with the classic water-solar system to minimize the compressor's duty and to reduce power consumption in heating the amount of water held in the pipe to be sent along the tube outside the evaporator. After that, it will be returned to the compressor, But at a lesser temperature, to minimize compressor workload and enhance cooling performance. Before the compressor was developed, a solar collector system had been created to maximize its temperature before reaching the compressor to improve C.O.P, and the difference in temperature was remarkable. The vapor-compression refrigerator unit was powered by many generators: solar collector that has been discharged, photovoltaic system, flat plate solar collector. Two groups of tests have been performed experimentally on the partial solar compression refrigerator integrated into a hybrid system. First in the vapor compression refrigerator only, and the second in the Hybrid solar compression refrigerator incorporated. Total sunlight and different temperatures, current, and voltage were measured for many months each hour of the day. The performance coefficient was determined found 2.019, 2.432 respectively. Many auxiliary instruments are utilized to measure the temperature in irradiation networks, voltage, and night-time current every hour.
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Sairamakrishna, B., T. Gopala Rao, and N. Rama Krishna. "Cop Enhancement of Vapour Compression Refrigeration System." Indian Journal of Production and Thermal Engineering 1, no. 2 (June 10, 2021): 1–6. http://dx.doi.org/10.35940/ijpte.b2004.061221.
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This experimental investigation exemplifies the design and testing of diffuser at compressor inlet and nozzle at condenser outlet in vapour compression refrigeration system with the help of R134a refrigerant. The diffuser with divergence angle of 12°,14° and the nozzle with convergent angle 12°,14° are designed for same inlet and outlet diameters. Initially diffusers are tested at compressor inlet diffuser is used with inlet diameter equal to exit tube diameter of evaporator and outlet tube diameter is equal to suction tube diameter of the compressor. Diffuser helps to increases the pressure of the refrigerant before entering the compressor it will be helps to reduces the compression work and achieve higher performance of the vapour compression refrigeration system. Then nozzles are testing at condenser outlet, whereas nozzle inlet diameter equal to discharging tube diameter of condenser and outlet diameter equal to inlet diameter of expansion valve. Additional pressure drop in the nozzle helped to achieve higher performance of the vapour compression refrigeration system. The system is analyzes using the first and second laws of thermodynamics, to determine the refrigerating effect, the compressor work input, coefficient of performance (COP).
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B, Sairamakrishna, T. Gopala Rao, and Rama Krishna, N. "Cop Enhancement of Vapour Compression Refrigeration System." Indian Journal of Production and Thermal Engineering 1, no. 2 (June 10, 2021): 1–6. http://dx.doi.org/10.35940/ijpte.b2004.06122.
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This experimental investigation exemplifies the design and testing of diffuser at compressor inlet and nozzle at condenser outlet in vapour compression refrigeration system with the help of R134a refrigerant. The diffuser with divergence angle of 12°,14° and the nozzle with convergent angle 12°,14° are designed for same inlet and outlet diameters. Initially diffusers are tested at compressor inlet diffuser is used with inlet diameter equal to exit tube diameter of evaporator and outlet tube diameter is equal to suction tube diameter of the compressor. Diffuser helps to increases the pressure of the refrigerant before entering the compressor it will be helps to reduces the compression work and achieve higher performance of the vapour compression refrigeration system. Then nozzles are testing at condenser outlet, whereas nozzle inlet diameter equal to discharging tube diameter of condenser and outlet diameter equal to inlet diameter of expansion valve. Additional pressure drop in the nozzle helped to achieve higher performance of the vapour compression refrigeration system. The system is analyzes using the first and second laws of thermodynamics, to determine the refrigerating effect, the compressor work input, coefficient of performance (COP).
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Karthick, Munuswamy, Senthil Karuppiah, and Varatharajan Kanthan. "Performance investigation and exergy analysis of vapor compression refrigeration system operated using R600a refrigerant and nanoadditive compressor oil." Thermal Science 24, no. 5 Part A (2020): 2977–89. http://dx.doi.org/10.2298/tsci180527024m.
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Compression of vaporized refrigerant is the essential process of the refrigeration cycle which is performed by using a compressor. The amount of power consumed by a refrigeration system is governed by the work input given to its compressor, which also determines the COP of the system. By reducing the work input given to the compressor, the power consumption of refrigerator is reduced along with the improvement in its COP. Nowadays, nanoparticles have emerged as the new generation additives in various working fluids because of their remarkable ability to improve the heat transfer, tribological and other thermophysical properties of the base fluid. In such a vein, we propose a compressor oil based nanofluid prepared by dispersing nanoparticles into the conventional compressor oil. In the present study, four samples of nanoadditive compressor oil were prepared by dispersing the nanoparticles like Al2O3, TiO2, and ZnO into the conventional mineral oil as a lubricant. The tribological properties of this four samples were studied, out of which one sample gave a better lubrication and heat transfer properties which are considered as one of the key parameters for reducing work input to the compressor, this can result in reduced power consumption, with enhancement of COP. These results are analyzed experimentally by carrying out performance and exergy analysis in a vapor compression refrigeration system, using R600a as a refrigerant. The experimental results show that, there is an improvement of COP by 14.61% and exergy efficiency by 7.51%. Also, the efficiency defect in the major components of vapor compression refrigeration system has been reduced effectively.
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Liu, Xue Ping, Yang Cui, and Lang Gao. "Deciding the Recycling Progress of Refrigerator Compressor Based on Naïve Bayes." Advanced Materials Research 1025-1026 (September 2014): 1088–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.1088.
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Compressor is the heart of refrigeration system, and the most valuable part in a refrigerator from the perspective of recycling. So the recycling progress (remanufacturing or recycling) is critical for taking full advantage of the compressors that run out of use. This paper introduces a method to decide whether to remanufacture or to recycle a compressor based on Naïve Bayes.
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Zhang, Li, Shuo Zhang, Yuan Yuan Zhang, and Yan Miao Ma. "A Harmonic Response Analysis of Food Refrigeration Compressor Based on Abaqus." Applied Mechanics and Materials 215-216 (November 2012): 950–54. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.950.
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A harmonic response analysis was conducted on semi-hermetic refrigeration compressor by Abaqus software. The vibration displacement and acceleration response spectrums of the compressor’s key points were obtained. The vibration characteristics of the compressor show that the harmonic response analysis result is consistent with the experimental one. The vibration of the compressor at 50Hz is the most dramatic. The first trough in each direction is found around 70Hz, and after that each direction’s acceleration goes up significantly. At the same time, the conclusion verifies the vibration of compressor’s bottom corners by LMS Test. Lab Signature Testing. The paper provides a scientific reference for the further study on vibration and noise reduction in food refrigeration compressors.
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Wu, Huagen, Hao Huang, Beiyu Zhang, Baoshun Xiong, and Kanlong Lin. "CFD Simulation and Experimental Study of Working Process of Screw Refrigeration Compressor with R134a." Energies 12, no. 11 (May 29, 2019): 2054. http://dx.doi.org/10.3390/en12112054.
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Twin-screw refrigeration compressors have been widely used in many industry applications due to their unique advantages. The performance of twin-screw refrigeration compressors is generally predicted by one-dimensional numerical simulation or empirical methods; however, the above methods cannot obtain the distribution of the fluid pressure field and temperature field inside the compressor. In this paper, a three-dimensional model was established based on the experimental twin-screw refrigeration compressor. The internal flow field of the twin-screw compressor was simulated by computational fluid dynamics (CFD) software using structured dynamic grid technology. The flow and thermodynamic characteristics of the fluid inside the compressor were analyzed. The distribution of the internal pressure field, temperature field, and velocity field in the compressor were obtained. Comparing the P-θ indicator diagram and the performance parameters of the compressor with the experimental results, it was found that the results of the three-dimensional numerical simulation were consistent with the experimental data. The maximum error was up to 2.578% on the adiabatic efficiency at the partial load working condition. The accuracy of the 3D numerical simulation of the screw compressors was validated and a new method for predicting the performance of twin-screw refrigeration compressors was presented that will be helpful in their design.
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Лаженко, А. С., and Т. Я. Біла. "ОЦІНКА ЕНЕРГОЕФЕКТИВНОСТІ ВИКОРИСТАННЯ СИСТЕМ КЕРУВАННЯ МОТОР-КОМПРЕСОРОМ ПОБУТОВОГО ХОЛОДИЛЬНИКА." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 146, no. 3 (January 11, 2021): 58–68. http://dx.doi.org/10.30857/1813-6796.2020.3.5.
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Determining the rational structure of the automatic control system of the motor-compressor, which provides minimal energy losses when switching on and going to a steady state mode of operation of a household refrigerator. The methods of simulation modeling, comparative analysis, research of control systems and the main provisions of technical thermodynamics and the theory of automatic control are used in the work. The paper considers the principle of operation of the refrigeration unit of a household refrigerator, schematically shows its main elements and the relationship with the steam compression cycle. Simulation models of automatic control systems based on proportional-integral-differential controller, fuzzy and hybrid controllers have been developed. The proposed models allow to evaluate the quality of temperature control in the refrigeration compartment and to determine energy losses during transients. The results of computer simulation of transients in temperature control systems due to changes in the performance of the motor-compressor and the obtained values of power losses are presented. It is established that the smallest losses of the electric power at instant increase of heat inflows in refrigerating department occur at application of a fuzzy regulator. It is determined that the use of fuzzy controllers in automatic control systems reduces the duration of transients, the time of the first negotiation, the number of oscillations, but leads to static error and increases the maximum deviation from the set temperature in the refrigerator compartment. Simulation models of control systems of the motor-compressor of a household refrigerator for assessment of quality of regulation and definition of losses of the electric power during transient processes are developed. The ways to increase the energy efficiency of household refrigerators through the introduction of control systems with fuzzy regulators are proposed.
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Лаженко, А. С., and Т. Я. Біла. "ОЦІНКА ЕНЕРГОЕФЕКТИВНОСТІ ВИКОРИСТАННЯ СИСТЕМ КЕРУВАННЯ МОТОР-КОМПРЕСОРОМ ПОБУТОВОГО ХОЛОДИЛЬНИКА." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 146, no. 3 (January 11, 2021): 58–68. http://dx.doi.org/10.30857/1813-6796.2020.3.5.
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Determining the rational structure of the automatic control system of the motor-compressor, which provides minimal energy losses when switching on and going to a steady state mode of operation of a household refrigerator. The methods of simulation modeling, comparative analysis, research of control systems and the main provisions of technical thermodynamics and the theory of automatic control are used in the work. The paper considers the principle of operation of the refrigeration unit of a household refrigerator, schematically shows its main elements and the relationship with the steam compression cycle. Simulation models of automatic control systems based on proportional-integral-differential controller, fuzzy and hybrid controllers have been developed. The proposed models allow to evaluate the quality of temperature control in the refrigeration compartment and to determine energy losses during transients. The results of computer simulation of transients in temperature control systems due to changes in the performance of the motor-compressor and the obtained values of power losses are presented. It is established that the smallest losses of the electric power at instant increase of heat inflows in refrigerating department occur at application of a fuzzy regulator. It is determined that the use of fuzzy controllers in automatic control systems reduces the duration of transients, the time of the first negotiation, the number of oscillations, but leads to static error and increases the maximum deviation from the set temperature in the refrigerator compartment. Simulation models of control systems of the motor-compressor of a household refrigerator for assessment of quality of regulation and definition of losses of the electric power during transient processes are developed. The ways to increase the energy efficiency of household refrigerators through the introduction of control systems with fuzzy regulators are proposed.
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Li, Jie, Xin Ping Ou Yang, and Lian Jie Zhang. "Structure Design of a New Kind of Rotary Refrigeration Compressor." Advanced Materials Research 201-203 (February 2011): 2544–49. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.2544.
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This paper introduces the working principle and components structure of a new kind rotary refrigeration compressor which receives the merits of some existing rotary refrigeration compressors and discards some application limitation. The new type refrigeration compressor has the characteristics of fewer parts as well as simple structure, easy manufacturing, smooth operation and wide application capacity. In this paper the author puts emphasis on the discharge structure, capacity regulation mechanism, piston flexibleness and seal body.
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Chandra, M. Ravi, and Kappati Manikanth Reddy. "Investigation Analysis on the Performance Improvement of a Vapor Compression Refrigeration System." Applied Mechanics and Materials 592-594 (July 2014): 1638–41. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1638.
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The principal objective of the paper is to modify the conventional vapor compression refrigeration system by connecting heat exchangers thereby heating and cooling of water is done simultaneously. The vapor refrigerant is supplied to the hermetic sealed compressor where the refrigerant gets compressed to a temperature of 100-120◦ C. The compressor is connected to a counter flow heat exchanger. Experimentation is carried out to design and manufacture a modified vapor compression refrigeration system. The main parameters considered during the design are connection of a compressor to a hermetically sealed compressor, keeping polyurethane foam as insulating material, adjusting the capillary tube and finned evaporators. The operations carried during the fabrication of equipment are bending, brazing and arc welding process. After the experimental setup has been fabricated the system is checked for the performance by using refrigerants R-22 and R-407.The results are plotted between heating temperatures, cooling temperatures with respect to time in minutes.
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Sukhomlinov, Igor, and Mihail Golovin. "Expedited method of testing and refinement of refrigeration centrifugal compressors." E3S Web of Conferences 140 (2019): 06004. http://dx.doi.org/10.1051/e3sconf/201914006004.
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Currently existing regulatory documents assume that refrigeration compressors are tested as part of test rigs with heat-exchange equipment. Given the high energy intensity of centrifugal compressors, the drive power of which in cooling mode with a cold capacity of up to 8.0 MW can be 2.0 or more MW, the creation of test rigs for preliminary and acceptance tests at the manufacturer’s factory requires a large investment. An alternative to the considered refrigeration centrifugal compressors test method is a test on a test rig in which the agent is partially condensed. In this case, an evaporator and a full-sized condenser are not required. The mathematical model of the refrigeration centrifugal compressors developed by JSC VNIIKHOLODMASH, allows testing of the refrigeration centrifugal compressors in model conditions, when the entire compressor operation cycle at the test rig is carried out in the area of superheated steam. Since the refrigeration centrifugal compressors mathematical model is based on physical simulation of compression processes in model stages at different values of conditional Mach numbers, dimensionless characteristics of model stages can be used to calculate the characteristic of the created compressor when operating under new conditions. The implementation of the model test method provides reduction of testing time due to absence of phase changes of the agent, improves the accuracy of the obtained results, reduces of power consumption, simplifies the test rig, and reduces consumption of the agent for filling the rig and water for cooling the agent.
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Samuel, K. John, R. Thundil Karuppa Raj, and G. Edison. "An Overview of Parameters Influencing the Performance of Hermetic Reciprocating Compressor for Domestic Applications." International Journal of Air-Conditioning and Refrigeration 26, no. 04 (December 2018): 1830003. http://dx.doi.org/10.1142/s2010132518300033.
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The performance of the refrigeration system mainly depends on the hermetic compressor. Of different compressors used in the refrigeration and air conditioning industries, hermetic reciprocating compressors are still efficient and have its place in domestic applications. This paper presents a review of most critical parameters and their influence on the hermetic reciprocating compressor performance. A detailed study is done on parameters like backflow, effective force and flow areas, valve dynamic behavior, etc. This study mainly concentrated on compressor valves which influence the performance of the hermetic compressor to a much greater extent. Finally, the study reveals that these parameters are playing a vital role in influencing the performance of the refrigeration system. Advanced numerical techniques involving combining fluid flow and structural analysis involving Fluid Structure Interaction (FSI) may give a better insight of the flow physics happening inside the compressors and the effect of fluid force on valve fluttering, back pressure and dynamics characteristics can be revealed in depth to optimize the performance of the hermetic compressor for household applications involving air conditioners, refrigerators, water coolers, chillers, etc.
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Al-Hassani, Ahmed H., and Alaa R. Al-Badri. "Effects of compressor speed and electronic expansion valve opening on the performance of R410a water chiller system." Wasit Journal of Engineering Sciences 8, no. 1 (July 5, 2020): 12–20. http://dx.doi.org/10.31185/ejuow.vol8.iss1.151.
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Refrigeration and air conditioning systems consume high rates of electrical energy of the total global power consumption. The major part of this energy is used by compressor which is the main equipment in vapor compression refrigeration systems. In this study, the performance of a variable speed chilled water refrigeration system with electronic expansion valve (EEV) is experimentally investigated. The system is composed of variable speed rotary compressor, water cooled condenser, electronic expansion valve, and evaporator with refrigerant R410a for one tone cooling capacity. The results showed that the EEV opening was related to the compressor speed at limits of refrigerant subcool and system stability to achieve better performance. Refrigerant superheats increased with closing the EEV at constant compressor speed. Moreover, the degree of superheat was inversely proportional to the compressor speed at constant EEV opening. The coefficient of performance (COP) was improved by about 2.2 to 4.0% by controlling the EEV at constant compressor speed. Increasing compressor speed from 1200 to 3600 rpm resulted in decreasing system COP from 5.2 to 2.35 due to the increase of the power consumed by compressor.
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I Nyoman Suamir, I Made Rasta, Adi Winarta, I Wayan Adi Subagia, and Made Ery Arsana. "Study on the Performance of Scroll Compressor Applied for Medium Temperature Refrigeration System." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 83, no. 2 (June 8, 2021): 98–113. http://dx.doi.org/10.37934/arfmts.83.2.98113.
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Recent research shows great interest in increasing energy efficiency of a refrigeration system and finding appropriate configurations to optimize its performance. One of the main component in the refrigeration system is compressor. Therefore, the compressor plays an important role in a refrigeration system for energy performance optimization. The study is aimed to experimentally investigate temperature and energy performance of a scroll compressor applied for medium temperature refrigeration systems. Tests were conducted in a water cooled medium temperature refrigeration system. Temperature performance evaluation of the compressor referred to the IEEE Standard 112, while energy efficiency of the compressor was calculated from the energy performance of the refrigeration system. The results clearly show that evaporating temperature together with degree of superheat at suction line of the compressor can significantly affect temperature performance of the scroll compressor. Results of the study have also shown significant improvement on the compressor energy efficiency accounted for 10.4% when the evaporating temperature increases from -8.3 °C to -2.4 °C.
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Cheng, Zhi Wen. "Performance Analysis of a Novel Compression Refrigeration System." Applied Mechanics and Materials 721 (December 2014): 170–73. http://dx.doi.org/10.4028/www.scientific.net/amm.721.170.
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In this paper, the theoretical analysis and calculation were put forward for the novel compression refrigeration cycle, new cycle compared with conventional compression refrigeration cycle adding a jet pump and evaporator to reduce throttling losses and improve the compressor inlet pressure. The results show that COP decreases with the increase of condensing temperature, with the increase of evaporation temperature increased, and decreased with the increase of the ejector coefficient. Novel compression refrigeration cycle coefficient of performance than the conventional compression refrigeration system performance coefficient increased by 8-15%.
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Siddharth, Raju, Korody Jagannath, P. Kini Giridhar, and K. Kedlaya Vishnumurthy. "Design and Simulation of a Vapour Compression Refrigeration System Using Phase Change Material." MATEC Web of Conferences 144 (2018): 04002. http://dx.doi.org/10.1051/matecconf/201814404002.
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The paper details the design and simulation of a solar powered vapour compression refrigeration system. The effect of a phase change material, in this case ice, on a vapour compression refrigeration system powered by solar panels is discussed. The battery and solar panels were sized to allow the system to function as an autonomous unit for a minimum of 12 hours. It was concluded that the presence of a phase change material in the refrigeration system caused a considerable increase in both the on and off time of the compressor. The ratio by which the on time increased was greater than the ratio by which the off time was increased. There was a 219% increase in the on time, a 139% increase in the compressor off time and a 3.5% increase in compressor work accompanied by a 5.5% reduction in COP. Thus, under conditions where there is enough load in the system to cause the initial on and off times of the compressor to be comparable, the presence of a phase change material may result in a greater on period than an off period for the compressor.
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Dudar, Adam, Dariusz Butrymowicz, Kamil Śmierciew, and Jarosław Karwacki. "Exergy analysis of operation of two-phase ejector in compression refrigeration systems." Archives of Thermodynamics 34, no. 4 (December 1, 2013): 107–22. http://dx.doi.org/10.2478/aoter-2013-0032.
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Abstract Paper deals with theoretical analysis of possible efficiency increase of compression refrigeration cycles by means of application of a twophase ejector. Application of the two phase ejector in subcritical refrigeration system as a booster compressor is discussed in the paper. Results of exergy analysis of the system operating with various working fluids for various operating conditions have been shown. Analysis showed possible exergy efficiency increase of refrigeration compression cycle.
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Vali, Shaik Sharmas, Talanki Puttaranga Setty, and Ashok Babu. "Analytical computation of thermodynamic performance parameters of actual vapour compression refrigeration system with R22, R32, R134a, R152a, R290 and R1270." MATEC Web of Conferences 144 (2018): 04009. http://dx.doi.org/10.1051/matecconf/201814404009.
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The present work focuses on analytical computation of thermodynamic performance of actual vapour compression refrigeration system by using six pure refrigerants. The refrigerants are namely R22, R32, R134a, R152a, R290 and R1270 respectively. A MATLAB code is developed to compute the thermodynamic performance parameters of actual vapour compression system such as refrigeration effect, compressor work, COP, power per ton of refrigeration, compressor discharge temperature and volumetric refrigeration capacity at condensing and evaporating temperatures of 54.4oC and 7.2oC respectively. Analytical results exhibited that COP of both R32 and R134a are 15.95% and 11.71% higher among the six investigated refrigerants. However R32 and R134a cannot be replaced directly into R22 system. This is due to their higher compressor discharge temperature and poor volumetric capacity respectively. The discharge temperature of both R1270 and R290 are lower than R22 by 20-26oC. Volumetric refrigeration capacity of R1270 (3197 kJ/m3) is very close to that of volumetric capacity of R22 (3251 kJ/m3). Both R1270 and R290 shows good miscibility with R22 mineral oil. Overall R1270 would be a suitable ecofriendly refrigerant to replace R22 from the stand point of ODP, GWP, volumetric capacity, discharge temperature and miscibility with mineral oil although its COP is lower.
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Ramanathan, Anand, and Prabhakaran Gunasekaran. "Simulation of absorption refrigeration system for automobile application." Thermal Science 12, no. 3 (2008): 5–13. http://dx.doi.org/10.2298/tsci0803005r.
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An automotive air-conditioning system based on absorption refrigeration cycle has been simulated. This waste heat driven vapor absorption refrigeration system is one alternate to the currently used vapour compression refrigeration system for automotive air-conditioning. Performance analysis of vapor absorption refrigeration system has been done by developing a steady-state simulation model to find the limitation of the proposed system. The water-lithium bromide pair is used as a working mixture for its favorable thermodynamic and transport properties compared to the conventional refrigerants utilized in vapor compression refrigeration applications. The pump power required for the proposed vapor absorption refrigeration system was found lesser than the power required to operate the compressor used in the conventional vapor compression refrigeration system. A possible arrangement of the absorption system for automobile application is proposed.
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Riffe, Delmer R. "Discharge muffler for refrigeration compressor." Journal of the Acoustical Society of America 94, no. 4 (October 1993): 2471. http://dx.doi.org/10.1121/1.407401.
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Okereke, Chukwuemeka J., Idehai O. Ohijeagbon, and Olumuyiwa A. Lasode. "Energy and Exergy Analysis of Vapor Compression Refrigeration System with Flooded Evaporator." International Journal of Air-Conditioning and Refrigeration 27, no. 04 (December 2019): 1950041. http://dx.doi.org/10.1142/s201013251950041x.
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In this study, energy and exergy analysis was used to evaluate the performance of a vapor compression refrigeration system with a flooded evaporator and the causes of high temperatures of beverage during the production process determined. Subsequently, the components of the operation that require modification were identified in order to improve the system performance. The actual operating parameters related to energy and exergy analysis of the investigated beverage manufacturing plant were measured, the thermal properties of the beverage were determined from a calorimeter experiment, and mathematical models were developed based on the first and second laws of thermodynamics from the literature. The system energy and exergy efficiencies were 57.46% and 21.17%, respectively, whereas the system exergy destruction was 695.71[Formula: see text]kW. The highest exergy destruction among the components of the refrigeration system occurred at the cooling plate, followed by the ammonia compressor. The cooling plate also experienced a loss in the refrigerating effect of 43.59[Formula: see text]kW. Therefore, the cooling plate is the area with the highest potential for improvement. The ammonia compressor presents another potential area of improvement, which includes operating the compressor at a high compression ratio and high superheated temperature. However, the reduction of beverage inlet mass flow rate at the cooling plate offers the best opportunity to achieve a low beverage temperature between 1.00∘C and 2.00∘C and decreasing the system exergy destruction without incurring additional investment costs.
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Stosic, N., I. K. Smith, and A. Kovacevic. "Opportunities for innovation with screw compressors." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 217, no. 3 (August 1, 2003): 157–70. http://dx.doi.org/10.1177/095440890321700301.
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It is falsely considered, but widely accepted, that little can now be done to improve the screw compressor process and design. Screw compressors are indeed a mature product today and they form a highly competitive market, especially the oil-flooded air compressor. However, the simultaneous efforts of a large number of manufacturers have resulted in a compact and efficient oil-flooded screw compressor machine. Even small design details now tell the achievement of better compressor efficiency, and there is still some place left for implementation of new methods and procedures that will undoubtedly result in a better final product. New rotor generation procedures, rotor and compressor design optimization for a specified compressor duty and specialized compressor design are innovation elements that are continually improving and developing screw compressors and opening up hitherto unknown ways to produce compressors with better features. Also, the development of a combined compression and expansion machine is reported which could further increase the useful range of application of such machines, especially in refrigeration systems. A review of recent results of computational fluid dynamics (CFD) in screw machines is also given in the paper.
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Yang, Juan Juan, Ke Li, and Xin Yang Cui. "Experimental Study on Miniature-Refrigeration System." Key Engineering Materials 531-532 (December 2012): 584–87. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.584.
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A prototype of miniature cooling system was developed, which mainly consists of the miniature compressor from DONG YUAN and a spiral-tube evaporator designed by ourselves. The performances of the prototype with different parameters were tested. The influence of ambient temperature, chilled water temperature on the performance of the cooling system were analyzed. The best operating conditions and the optimum amount of refrigerant were obtained. Conclusions were gotten as follows:1) With environment temperature rising, compression ratio increases, system power consumption increases and refrigerating capacity COP decreases. 2) With chilled water temperature rising, compression ratio and power consumption decrease, refrigerating capacity increases, and COP increases rapidly.3) Paper gets system performance: refrigerating capacity is 63 W, compressor power consumption is 24.5 W, COP value is 2.57. in operation condition: refrigerant amount is 40g, environment temperature is 30°C, chilled water temperature is 40 °C, chilled water mass flow is 45 kg/h.
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Lee, Jaeseon, and Issam Mudawar. "Implementation of Microchannel Evaporator for High-Heat-Flux Refrigeration Cooling Applications." Journal of Electronic Packaging 128, no. 1 (June 17, 2005): 30–37. http://dx.doi.org/10.1115/1.2159006.
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While most recently electronic cooling studies have been focused on removing the heat from high-power-density devices, the present study also explores means of greatly decreasing the device operating temperature. This is achieved by incorporating a microchannel heat sink as an evaporator in an R134a refrigeration loop. This system is capable of maintaining device temperatures below 55°C while dissipating in excess of 100W∕cm2. It is shown that while higher heat transfer coefficients are possible with greater mass velocities, those conditions are typically associated with wet compression corresponding to evaporator exit quality below unity and liquid entrainment at the compressor inlet. Wet compression compromises compressor performance and reliability as well as refrigeration cycle efficiency and therefore must be minimized by maintaining only slightly superheated conditions at the compressor inlet, or using a wet-compression-tolerant compressor. A parametric study of the effects of channel geometry on heat sink performance points to channels with small width and high aspect ratio as yielding superior thermal performance corresponding to only a modest penalty in pressure drop.
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Terehovics, Edvins, Ivars Veidenbergs, and Dagnija Blumberga. "Analysis of Operation Parameters of Fish Refrigeration by Exergy Analysis. Case Study." Environmental and Climate Technologies 23, no. 1 (January 1, 2019): 229–41. http://dx.doi.org/10.2478/rtuect-2019-0015.
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Abstract Unlike energy efficiency, in terms of exergy efficiency it is possible to compare the existing operation of an energy conversion system with the ideal operation. Exergy loses and exergy destruction make it possible to identify the shortcomings of an existing system, which should be improved immediately. With exergy analysis, it is possible to identify the priority actions that need to be taken in order to improve the functioning of the system: greater exergy loss prevention is the highest priority. Energy efficiency refers to the useful work and investments needed to obtain useful work and investments needed to obtain energy efficiency; this is important to some extent, but the effectiveness of exergy makes it possible to compare system performance with the ideal. Results shows that the highest exergy destruction of a single-stage compressor refrigeration system from all working condition is found when ambient temperature and freezer temperature difference is 10 ºC, pressure in compressor is 0.62 MPa, ammonia temperature after compressor is 90 ºC, total exergy destruction of single-stage compressor refrigeration system 97.84 kW. The highest exergy efficiency of a single-stage compressor refrigeration system from all the working conditions is found when ambient temperature and freezer temperature difference is 39 ºC, pressure in compressor is 0.45 MPa, ammonia temperature after compressor is 128 ºC, exergy efficiency of a single-stage compressor refrigeration system is 59.76 %. The highest total exergy destruction of a two-stage compressor refrigeration system from among all the working conditions is found to be when the ambient temperature and freezer temperature difference is at 13 ºC, pressure in compressor 0.44 MPa, ammonia temperature after compressor 76 ºC, total exergy destruction 83.86 kW. The highest exergy efficiency of a two-stage compressor refrigeration system from among all the working conditions is found to be at an ambient temperature and freezer temperature difference of 39 ºC, pressure in compressor 0.56 MPa, ammonia temperature after compressor 92 ºC, exergy efficiency 53.55 %.
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Mishra, Vinay, and Dr H. K. Paliwal. "Analysis of Airconditioning System Using Single-Rotor Wind Turbine Power, Dual Rotor Wind Turbine Power, and Ducted Dual Rotor Wind Turbine Power As Input to Compressor." Revista Gestão Inovação e Tecnologias 11, no. 4 (July 22, 2021): 2952–63. http://dx.doi.org/10.47059/revistageintec.v11i4.2331.
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As vapor compression refrigeration system is the best-suited system used in the present scenario due to its various advantages, in the present paper MATLAB analysis is done for the analysis of simple VCR to calculate COP and refrigeration effect.in the present paper R134a refrigerant is used as a refrigerant.as we know a certain amount of power is used to drive the compressor input in conventional VCR system uses electrical power to convert into mechanical shaft rotation with certain rotation, power and torque.in this paper specific power torque and rotation is given to the compressor without any electrical motor. the power obtains from an SRWT, DRWT, and DDRWT with specific torque power and rotation. then after analysis is carried out to get the COP and Refrigeration Effect.
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Mishra, Abhishek, Ankur Kumar Choudhary, Taniya Tomar, and Jagannath Korody. "Thermoacoustic Refrigerator for High Temperature Gradient." MATEC Web of Conferences 144 (2018): 04003. http://dx.doi.org/10.1051/matecconf/201814404003.
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Leakage of HFCs, thermal shocks to sensitive devices, moving mechanical components which in turn require more maintenance, are some of the cons of a conventional vapor compression system .The newest field in refrigeration overcoming such flaws is Thermoacoustic refrigerator (TAR), where the sound energy is used to generate a temperature difference which can be used for refrigeration. TAR are environment friendly, do not use any kind of refrigerants, and as the compressor and expander are not used, hence, its life is more than a conventional VCR. The objective is to obtain a substantial temperature gradient using a Thermoacoustic Refrigerator. The methodology is to choose the suitable material and design the prototype. A large part of this project is devoted to explore the different designs for thermo acoustic refrigerators, and select the optimum one for maximum utility. With the present system, it was possible to achieve a temperature difference across the stack of 14 K.
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Alduqri, Y. A., and Md Nor Musa. "Theoretical Study of a Novel Four-Chamber Rotary Compressor: Design and Thermodynamic Analysis." Applied Mechanics and Materials 819 (January 2016): 46–57. http://dx.doi.org/10.4028/www.scientific.net/amm.819.46.
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A novel four-chamber rotary compressor (FCRC) is being developed for a refrigerator and an air-conditioning system. The novelty lies in the usage of three rotating sleeves and two oppositely installed vanes each has one end fixed to an outer sleeve and the other end to a rotor, respectively. In this paper, the swept volume, the delivered pressure, the work and the power of the FCRC are formulated and analyzed. The compressor configuration and thermodynamic analysis are based on the 174 cc swept volume with R134a as the compressed gas. Considering the encouraging results, added by design simplicity of mainly cylindrical shaped components, the proposed FCRC is reckoned to be very suitable to be used for air-conditioning and refrigeration applications.
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Tyczewski, Przemysław. "Investigation of the influence of Ti-Al-Cr-N coating on the surface condition of cooling compressor elements." AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, no. 12 (December 31, 2018): 685–88. http://dx.doi.org/10.24136/atest.2018.478.
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Elements of refrigeration compressors, may be exposed to various types of wear processes. The presence of the refrigerant makes the lubricating and anti-wear properties of the oil-medium mixture much worse than the oil without refrigerant. The paper presents the effect of using the Ti-AI-Cr-N coating on the surface condition of friction junction occurring in compressors of chillers. The tests were carried out using a model friction machine simulating the element of a refrigeration compressor.
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Makwana, Yasin, Dereje Agonafer, and Dan Manole. "Impact of TXV and Compressor in the Stability of a High-End Computer Refrigeration System." Journal of Electronic Packaging 126, no. 4 (December 1, 2004): 554–59. http://dx.doi.org/10.1115/1.1827272.
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The combination of increased power dissipation and increased packaging density has led to substantial increases in chip and module heat flux in high-end computers. The challenge is to limit the rise in chip temperature above the ambient. In the past, virtually all commercial computers were designed to operate at temperatures above the ambient. However, researchers have identified the advantages of operating electronics at low temperatures. Until recently, large-scale scientific computers used direct immersion cooling of single-chip modules. The current research focuses on mainframes (computer system), which uses a conventional refrigeration system to maintain chip temperatures below that of comparable air-cooled systems, but well above cryogenic temperatures. Multivariable control of compressor speed along with thermostatic expansion valve (TXV) opening can give better stability and performance. TXV is a mechanical controlling device used in the refrigeration system. The compressor is the only mechanical-working component in the refrigeration cycle that circulates refrigerant through the system continuously. Hence, controlling the compressor is an important aspect. The control objective is defined as improving the transient behavior of the vapor compression cycle for the refrigeration system operating around an evaporator set-point temperature. The system behavior is studied in two cases, TXV being the only control element in the first case, while TXV and a compressor both act as control elements in the other case.
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Zhang, Li, Shuo Zhang, and Guang Yuan Nie. "The Acoustic Enclosure Design of the Refrigeration Compressor." Applied Mechanics and Materials 289 (February 2013): 75–80. http://dx.doi.org/10.4028/www.scientific.net/amm.289.75.
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In this paper, in order to reduce the external radiation of food refrigeration compressors noise, the main noise frequency analysis based on the theoretical calculation and practical experiment is carried out and the acoustic enclosure design is conducted. Conventional sound-absorbing material adopts rock wool and glass wool which have poor environmental protection. In the design process the environmental friendly melamine cotton is chosen as the sound-absorbing material that has not ever been massively adopted. Whats more, with a consideration of ventilation and heat dissipation, acoustic enclosure interior is designed with muffler air duct and the low-speed and low-noise fan. Therefore, both the normal operation of the compressor and the sound insulation of the acoustic enclosure are ensured in this way. Then with the sound level meter the noise A-weighted SPLs of the compressor with and without the enclosure are measured and are compared with each other. The results show that after covering the acoustic enclosure the compressors noise is less than 60 dB, which meets the design requirements of noise control. Therefore, it is easy to conclude that the sound insulation of the acoustic enclosure reaches the design standards and the acoustic enclosure design is feasible.
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UDDIN, KUTUB, TAKAHIKO MIYAZAKI, SHIGERU KOYAMA, and BIDYUT BARAN SAHA. "PERFORMANCE INVESTIGATION OF ADSORPTION–COMPRESSION HYBRID REFRIGERATION SYSTEMS." International Journal of Air-Conditioning and Refrigeration 21, no. 04 (December 2013): 1350024. http://dx.doi.org/10.1142/s2010132513500247.
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An analytical investigation on the performance of adsorption–compression hybrid refrigeration systems with two different cycle configurations, cascade type and subcool type has been performed. In the former type, a cascade condenser is used which works as a condenser for mechanical compression cycle and evaporator for adsorption cycle. In the latter type, an evaporative subcooler is used which subcool the fluid of mechanical compression cycle. The refrigerants examined for the mechanical compression cycle are R134a, R152a, R1234yf and R1234ze whereas ethanol is the refrigerant for the adsorption cycle. The main feature of the proposed system is the capability to significantly reduce work input for the mechanical compressor which results up to 30% energy saving potential depending on the selection of refrigerant and system configuration. Based on the thermodynamic properties and laws the study analyzed the effect of the major design parameters such as evaporation temperature, compressor discharge pressure and desorption temperature on the system performances.
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Wu, Weifeng, Zhao Zhang, Xiaolin Wang, Liangwei Yang, and Quanke Feng. "A Bench Evaluation Test for Refrigeration Oils in a Refrigeration System Using a Screw Compressor." Applied Sciences 9, no. 15 (August 6, 2019): 3202. http://dx.doi.org/10.3390/app9153202.
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Refrigeration oil has a large effect on the performance of refrigeration systems. However, the physical and chemical indexes of fresh refrigeration oils often fail to reflect the actual operating characteristics, especially with respect to the degradation of refrigeration oils. In this paper, a bench evaluation test of refrigeration oils was carried out to investigate the degradation of synthetic refrigeration oils used with the refrigerant R134a, in a purpose-built, full-scale refrigeration system utilizing a screw compressor. To accelerate the degradation process of the refrigeration oil, the discharge temperature at the exit of the compressor was turned to a high level. Comparison tests of a mature refrigeration oil type A and a newly developed oil type B were performed under the same working conditions with 500 h of operating time. The performance of the screw compressor and refrigeration system was analyzed. The abrasion of the screw rotors and carbon deposition at the discharge port was investigated. Results showed that the bench evaluation test successfully predicted the degradation process of the refrigeration oils. The evolution analysis of the refrigeration oil viscosity and acid value during the bench evaluation test indicated that 15% of the physical and chemical indexes for refrigeration oil drain were too strict. Research work in this paper showed a more practical method to evaluate the performance of refrigeration oils through the bench evaluation test.
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Liang, Youcai, Zhibin Yu, and Wenguang Li. "A Waste Heat-Driven Cooling System Based on Combined Organic Rankine and Vapour Compression Refrigeration Cycles." Applied Sciences 9, no. 20 (October 11, 2019): 4242. http://dx.doi.org/10.3390/app9204242.
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In this paper, a heat driven cooling system that essentially integrated an organic Rankine cycle power plant with a vapour compression cycle refrigerator was investigated, aiming to provide an alternative to absorption refrigeration systems. The organic Rankine cycle (ORC) subsystem recovered energy from the exhaust gases of internal combustion engines to produce mechanical power. Through a transmission unit, the produced mechanical power was directly used to drive the compressor of the vapour compression cycle system to produce a refrigeration effect. Unlike the bulky vapour absorption cooling system, both the ORC power plant and vapour compression refrigerator could be scaled down to a few kilowatts, opening the possibility for developing a small-scale waste heat-driven cooling system that can be widely applied for waste heat recovery from large internal combustion engines of refrigerated ships, lorries, and trains. In this paper, a model was firstly established to simulate the proposed concept, on the basis of which it was optimized to identify the optimum operation condition. The results showed that the proposed concept is very promising for the development of heat-driven cooling systems for recovering waste heat from internal combustion engines’ exhaust gas.
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Gill, Jatinder, and Jagdev Singh. "Experimental Analysis of R134a/LPG as Replacement of R134a in a Vapor-Compression Refrigeration System." International Journal of Air-Conditioning and Refrigeration 25, no. 02 (April 4, 2017): 1750015. http://dx.doi.org/10.1142/s2010132517500158.
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This paper presents an experimental analysis of a vapor compression refrigeration system (VCRS) using the mixture of R134a and LPG with mass fractions of 28:72 as an alternative to R134a. In this work, we compare the energy performance of both refrigerants, R134a/LPG (28:72) and R134a, in a monitored vapor compression refrigeration system under a wide range of experimental conditions. So, the System with R134a/LPG (28:72) was tested by varying the capillary tube length and refrigerant charge under experimental conditions. Performance comparisons of both the systems are made taking refrigerant R134a as baseline, and the results show that the compressor power consumption, compressor discharge temperature and pull down time obtained with R134a/LPG (28:72) of 118[Formula: see text]g and capillary tube length of 5.1 m in vapor compression refrigeration system are about 4.4% 2.4% and 5.3%, respectively, lower than that obtained with R134a in the studied range. Also, when using R134a/LPG (28:72), the system shows values of refrigeration capacity and COP are about 10.6% and 15.2% respectively, higher than those obtained using R134a, In conclusion, the mixing refrigerant R134a/LPG proposed in this study seems to be an appropriate long-term candidate to replace R134a as a new generation refrigerant of VCRS, because of its well environmentally acceptable properties and its favorable refrigeration performances.
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Chang, Jincai, Qiuling Pan, Zhihao Shen, and Hao Qin. "Intelligent Prediction of Refrigerant Amounts Based on Internet of Things." Complexity 2020 (February 3, 2020): 1–12. http://dx.doi.org/10.1155/2020/1743973.
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In a refrigeration unit, the amount of refrigerant has a substantial influence on the entire refrigeration system. To predict the amount of refrigerant in refrigerators with the best performance, this study used refrigerator data collected in real time via the Internet of Things, which were screened to include only the effective parameters related to the compressor and refrigeration properties (based on their practical significance and the research background) and cleaned by applying longitudinal dimensionality reduction and transverse dimensionality reduction. Then, on the basis of an idealized model for refrigerator data, a model of the relationships between refrigerant amount (the dependent variable) and temperature variation, refrigerator compartment temperature, freezer temperature, and other relevant parameters (independent variables) was established. A refrigeration model based on a neural network was then established for predicting the amount of refrigerant and was used to predict five unknown amounts of refrigerant from data sets. BP neural network and RBF neural network models were used to compare the prediction results and analyze the loss functions. From the results, it was concluded that the unknown amount of refrigerant was most likely to be 32.5 g. It is of great practical significance for refrigerator production and maintenance to study the prediction of the amount of refrigerant remaining in a refrigerator.
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Klein, S. A., and D. T. Reindl. "The Relationship of Optimum Heat Exchanger Allocation and Minimum Entropy Generation Rate for Refrigeration Cycles." Journal of Energy Resources Technology 120, no. 2 (June 1, 1998): 172–78. http://dx.doi.org/10.1115/1.2795030.
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This paper investigates the effect of heat exchanger allocation on overall system performance using both reverse Carnot and vapor compression refrigeration cycle models to calculate system performance and entropy generation rate. The algebraically simple constraints applied in previous studies are shown to be justifiable. The vapor compression model considers nonideal compressor performance, compressor volumetric efficiency, refrigerant properties, and throttling, in addition to mechanistic heat exchanger models. The results support the conclusions of previous studies in that maximum performance is observed when the condenser and evaporator thermal sizes are approximately equal. For air-to-air systems, this result indicates that the areas of the heat exchangers should be approximately equal. However, it is found that minimizing the entropy generation rate does not always result in the same design as maximizing the system performance unless the refrigeration capacity is fixed. Minimizing the entropy generation rate per unit capacity is found to always correspond to maximizing the coefficient of performance of refrigeration systems.
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Trzebiński, Daniel, and Ireneusz Szczygieł. "Thermal analysis of car air conditioning." Archives of Thermodynamics 31, no. 4 (October 1, 2010): 71–80. http://dx.doi.org/10.2478/v10173-010-0029-2.
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Thermal analysis of car air conditioningThermodynamic analysis of car air cooler is presented in this paper. Typical refrigerator cycles are studied. The first: with uncontrolled orifice and non controlled compressor and the second one with the thermostatic controlled expansion valve and externally controlled compressor. The influence of the refrigerant decrease and the change of the air temperature which gets to exchangers on the refrigeration efficiency of the system; was analysed. Also, its effectiveness and the power required to drive the compressor were investigated. The impact of improper refrigerant charge on the performance of air conditioning systems was also checked.
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Van Orshoven, D., S. A. Klein, and W. A. Beckman. "An Investigation of Water as a Refrigerant." Journal of Energy Resources Technology 115, no. 4 (December 1, 1993): 257–63. http://dx.doi.org/10.1115/1.2906430.
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This paper explores some of the basic thermodynamic and technical considerations involved in using water as a working fluid for refrigeration and heat pump cycles down to its freezing point of 0°C. It is first shown how the integration of the functions of refrigerant and heat transfer fluid can lead to energy savings, especially for the case of ice production. Next, the two fundamental requirements that the compressor must fulfill—handling a very large volume flow and achieving a large compression ratio—are described. A thermodynamic analysis of multistage compression follows to investigate the adiabatic head requirements and the large desuperheating irreversibility. It is concluded that a radically new type of vacuum compressor must be developed in order for water to be used as working fluid in vapor compression refrigeration cycles.
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Yang, Yu Fei, Wei Xing Yuan, and Yi Bin Liao. "Development of a Miniature Vapor-Compression Refrigeration System for Computer CPU Cooling." Applied Mechanics and Materials 321-324 (June 2013): 383–86. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.383.
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A miniature vapor-compression refrigeration system for cooling high power CPUs has been developed and tested. The refrigeration system is so small that it can be embedded into the computer case. The refrigerant used in the system is R-134a. The system consists of a miniature rotary DC compressor, a micro-channel condenser, a specially designed cold plate, a short tube restrictor, and related controlling electronics. The compressor is powered directly by the 12V DC power supply of the computer. The cold plate contacts the CPU surface directly and carries away the heat dissipation by conductivity. In a series of tests to cool an Intel Core i7-990X CPU that has 12 cores inside with the refrigeration system, the CPU core temperature can be kept at 23°C in default frequency 3.5GHz and 100% of workload. When the CPU is overclocked to 4.8GHz, the core temperature can be maintained at 59°C. Even when overclocked to 5.0GHz, the core temperature does not exceed 78°C. The test results validate the ability and potential of using vapor-compression refrigeration technology in high heat flux CPU cooling.
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Bultman, D. H., L. C. Burmeister, and V. Bortone. "Effects of Condenser Air Flow Blockage on Vapor-Compression Refrigerator Performance." Journal of Energy Resources Technology 117, no. 4 (December 1, 1995): 349–53. http://dx.doi.org/10.1115/1.2835434.
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The performance of a nominally 10.5-kW (3-ton) vapor-compression refrigeration system was numerically simulated for air flow rates across the condenser heat exchanger between 60 and 150 percent of the standard value. The results can be used for estimating the energy and cost savings achievable by restoring standard air flow rates across partially blocked condensers of vapor-compression refrigeration systems. The system coefficient of performance was predicted to decrease by 7.6 percent from its value of 2.912 at standard air flow when air flow across the condenser decreased by 40 percent. The associated pressure rise across the compressor increased by 19 percent above its standard value of 1151 kPa, suggesting that reduced compressor life might be the major economic consequence of condenser air flow blockage.
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Трушляков, Евгений Иванович, Николай Иванович Радченко, and Вениамин Сергеевич Ткаченко. "ПОДХОД К АНАЛИЗУ ЭФФЕКТИВНОСТИ РЕГУЛИРОВАНИЯ ХОЛОДОПРОИЗВОДИТЕЛЬНОСТИ СИСТЕМ КОНДИЦИОНИРОВАНИЯ ПРИТОЧНОГО ВОЗДУХА." Aerospace technic and technology, no. 6 (December 20, 2018): 29–33. http://dx.doi.org/10.32620/aktt.2018.6.04.
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It is determined that the operation of ambient air conditioning systems (AACS) has significant fluctuations in the heat load in accordance with current climatic conditions. This makes very problematic the application of refrigeration compressors with frequency converters, which are very effective for controlling the refrigeration capacity in closed air conditioning systems, in which the temperature control range and, accordingly, fluctuations in thermal load are insignificant in comparison with the ambient air cooling. For the purpose of analyzing the efficiency of controlling the refrigeration capacity of the AACS by changing the electric motor speed of the piston compressor in current climatic conditions, the entire range of changing current thermal loads is divided into two parts according to controlling the refrigeration capacity by appling a frequency converter: the part of effective cooling capacity adjustment without energy losses (without reducing the coefficient of performance) from nominal to its threshold value and the part of reduced refrigeration capacity without its controlling by a frequency converter. It is revealed that for the warmest summer month, the proportion of refrigeration capacity spent for cooling ambient air to the temperature of 10 °C with 50 % frequency controlling the refrigeration capacity is about 10 % of the total amount of that could be produced at nominal refrigeration capacity. At higher temperatures of cooled air is even less. This shows the low efficiency of controlling the refrigeration capacity of the AACS by changing the speed of rotation of the piston compressor electric motor and the need to use other methods of controlling the refrigeration capacity. The proposed approach to analyzing the efficiency of controlling the refrigeration capacity of AACS in current climatic conditions allows not only to estimate the efficiency of refrigeration capacity controlling method but also to reveal the reserves for increasing the efficiency of applying the available refrigeration capacity
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Mahdi, Loauy Abd Al-Azez, Wahid S. Mohammad, and Samir Akram Mahmood. "Exergy Analysis of a Domestic Refrigerator." Journal of Engineering 24, no. 9 (August 29, 2018): 1. http://dx.doi.org/10.31026/j.eng.2018.09.01.
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An energy and exergy thermodynamic analysis using EES program was done for a domestic refrigerator working with R-134a using vapor compression refrigeration cycle. The analysis deals with the system component, i.e. compressor, condenser, evaporator and the expansion device. The analysis depends on the entropy generation minimization approach to improve the refrigerator performance by exploring the optimum design points. These design points were derived from three different theories governing the entropy generation minimization using exergy analyzing method. These theories were first applied to find the optimum balance between the hot inner condenser area and the cold inner evaporator area of the refrigerator and between its hot and cold thermal conductances. Nine types of condensers were used according to its internal surface area and thermal conductance, in order to reach the minimum entropy generation in the refrigerator. The results showed that the compressor has the lowest exergy efficiency of 25%. The expansion device was the second component after the compressor with exergy efficiency of 92%, followed by the condenser with an efficiency of 93%. The evaporator was found to have an exergy efficiency of 98 %. The experimental tests were repeated for the nine condensers sizes with three different ambient temperatures 25℃, 30℃ and 35℃. The exergy analysis showed that the design of the refrigerator mainly depends on thermal conductance calculations rather than the surface inner area estimation.
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Lucas, Timothy S. "Refrigeration system having standing wave compressor." Journal of the Acoustical Society of America 93, no. 6 (June 1993): 3533. http://dx.doi.org/10.1121/1.405399.
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Nakai, H., N. Ino, and H. Hashimoto. "Piston-Ring Lubrication Problems for Refrigeration Compressors Considering Combined Effects of Supply Oil Quantity and Surface Roughness." Journal of Tribology 118, no. 2 (April 1, 1996): 286–91. http://dx.doi.org/10.1115/1.2831297.
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Reciprocating-type compressors are widely used for refrigeration systems, and an understanding of piston-ring lubrication in the compressor is vital for designers in reducing the energy losses due to friction because a substantial portion of friction in the compressors is attributable to the piston-ring assembly. This study aimed at developing a one-dimensional analysis for lubrication between the piston-ring and cylinder of refrigeration compressors considering the combined effects of supply oil quantity and surface roughness on piston-ring face and cylinder wall. In the theoretical model, the piston-ring is treated as a one-dimensional dynamically loaded bearing with combined sliding and squeezing motion. The one-dimensional modified Reynolds equation based on the average flow model by Patir and Cheng is used as a governing equation. In the analysis of the modified Reynolds equation, two-types of inlet boundary conditions, flooded condition and starvation condition, are applied at the leading edge according to the supply oil quantity, and the Reynolds boundary condition is applied at the trailing edge. A numerical procedure is then developed to estimate the cyclic variation of minimum film thickness, inlet and outlet positions of lubrication film and friction force, and the combined effects of supply oil quantity and surface roughness height are examined for a typical refrigeration compressor. It is clarified from the numerical results that the supply oil quantity and surface roughness affect significantly the friction force of the piston-ring for refrigeration compressors.
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Vali, Shaik Sharmas, Talanki Puttaranga Setty, and Ashok Babu. "Performance computation of window air conditioner with very low GWP near azeotropic refrigerant mixtures as a drop in Substitutes to R22." MATEC Web of Conferences 144 (2018): 04007. http://dx.doi.org/10.1051/matecconf/201814404007.
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The principal objective of the present study is to compute the thermodynamic performance of window air conditioner based on standard vapour compression refrigeration cycle using R22, R407C and nineteen refrigerant mixtures. In this work nineteen R290/R1270 blends at different compositions are developed. A MATLAB code is developed to compute the thermodynamic performance parameters of all the studied refrigerants at condensing and evaporating temperatures of 54.4°C and 7.2°C respectively. The performance parameters are cooling effect, compressor work, COP, compressor discharge temperature, power per ton of refrigeration and volumetric cooling capacity respectively. Analytical results revealed that COP of new binary mixture R290/R1270 (90/10 by mass %) is 2.82% higher among R22, R407C and nineteen studied refrigerants. Energy required by the compressor per ton of refrigeration for R290/R1270 (90/10 by mass %) is 2.73% lower among R22, R407C and nineteen studied fluids. The discharge temperature of the compressor for all the nineteen investigated blends are reduced by 6.0-8.9oC compared to R22. Overall thermodynamic performance of window air conditioner with R290/R1270 (90/10 by mass %) is better than R22 with significant savings in energy consumption and hence it is an energy efficient ecofriendly refrigerant mixture as a drop in substitute to R22.
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Sun, Yuyao, Jinfeng Wang, and Jing Xie. "Performance Optimizations of the Transcritical CO2 Two-Stage Compression Refrigeration System and Influences of the Auxiliary Gas Cooler." Energies 14, no. 17 (September 6, 2021): 5578. http://dx.doi.org/10.3390/en14175578.
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To optimize the performance of the transcritical CO2 two-stage compression refrigeration system, the energy analysis and the exergy analysis are conducted. It is found that higher COP, lower compression power, and less exergy destruction can be achieved when the auxiliary gas cooler is applied. Moreover, the discharge temperature of the compound compressor (HPS) can be reduced by decreasing the temperature at the outlet of the auxiliary gas cooler (Tagc,out). When the Tagc,out is reduced from 30 to 12 °C, the discharge temperature of the compound compressor (HPS) can be decreased by 13.83 °C. Furthermore, the COP and the exergy efficiency can be raised by enhancing the intermediate pressure. Based on these results, the optimizations of system design and system operation are put forward. The application of the auxiliary gas cooler can improve the performance of the transcritical CO2 two-stage compression refrigeration system. Operators can decrease the discharge temperature of the compound compressor (HPS) by reducing the Tagc,out, and increase the COP and the exergy efficiency by enhancing the intermediate pressure.
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Lebedev, B., L. Knaub, E. Lebedeva, and E. Pavlishko. "AN EXPERIMENTAL STUDY OF THE AMMONIA HERMETIC SMALL REFRIGERATION MACHINE." Аграрний вісник Причорномор'я, no. 94 (December 25, 2019): 139–54. http://dx.doi.org/10.37000/abbsl.2019.94.20.
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The article focuses on the study of the design parameters of small refrigerating machines. This article shows practical studies of the dependence of the energy parameters of the refrigerating machine on its design features.In particular, the dependence of the coefficient of performance upon the superheating of steam at the suction in the compressor was studied, and preventing method of such overheating for small refrigerating machines was proposed. At the second stage the possibility of using a regenerative heat exchanger in an ammonia refrigerating machine was examined. The advantages of its use are shown. In general, the possibility of increasing the refrigeration efficiency by changing design parameters of the refrigerating machine is shown.
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Cyklis, Piotr, and Karina Janisz. "An innovative ecological hybrid refrigeration cycle for high power refrigeration facility." Chemical and Process Engineering 36, no. 3 (September 1, 2015): 321–30. http://dx.doi.org/10.1515/cpe-2015-0022.
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Abstract Searching for new refrigerants is one of the most significant scientific problems in refrigeration. There are ecological refrigerants commonly known: H2O and CO2. H2O and CO2 known as natural refrigerants, but they have problems:a high freezing point of H2O and a low triple point of CO2. These problems can be solved by the application of a hybrid sorption-compression refrigeration cycle. The cycle combines the application possibility of H2O in the high temperature sorption stage and the low temperature application of CO2 in the compression stage. This solution gives significant energy savings in comparison with the two-stage compressor cycle and with the one-stage transcritical CO2 cycle. Besides, the sorption cycle may be powered by low temperature waste heat or renewable heat. This is an original idea of the authors. In the paper an analysis of the possible extension of this solution for high capacity industrial refrigeration is presented. The estimated energy savings as well as TEWI (Total Equivalent Warming Impact) index for ecological gains are calculated.