Parametric Analysis and Comparison of Ejector Expansion Refrigeration Cycles With Constant Area and Constant Pressure Ejectors

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Candeniz Seckin
Keyword(s):  
Parametric Analysis ◽  
Constant Pressure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Operational Parameters ◽  
Entrainment Ratio ◽  
Evaporator Temperature ◽  
Constant Area ◽  
Condenser Temperature

In this work, parametric analysis of ejector expansion refrigeration cycles (EERC) with two different types of ejectors (constant area (CA) ejector and constant pressure (CP) ejector) is performed, and comparison of the results is presented. Effects of variation in operational parameters (condenser temperature, evaporator temperature, and cooling capacity) on coefficient of performance (COP), entrainment ratio (w), and pressure lift factor (Plf) are investigated. The range of variation for evaporator temperature, condenser temperature, and cooling capacity are −5 to 15 °C, 50–70 °C, and 10–80 kW, respectively. The ejector refrigeration cycle is simulated by ees software. The obtained results are validated by the experimental data available in the literature. The refrigerant R134a is selected based on the merit of its environmental and performance characteristics. The results show that the effect of evaporator temperature is much higher than that of condenser temperature on Plf. In contrast, the influence of condenser temperature on COP is much stronger than that of evaporator temperature. It is seen that COP and Plf of ejector expansion refrigeration cycle with constant pressure ejector (CP-EERC) are higher than those of refrigeration cycle with constant area ejector.

scholarly journals Parametric analysis of a combined ejector-vapor compression refrigeration cycle

2020 ◽  
Vol 15 (3) ◽  
pp. 398-408
Author(s):  
I Ouelhazi ◽  
Y Ezzaalouni ◽  
L Kairouani
Keyword(s):  
Current Model ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Constant Area ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

Abstract From the last few years, the use of efficient ejector in refrigeration systems has been paid a lot of attention. In this article a description of a refrigeration system that combines a basic vapor compression refrigeration cycle with an ejector cooling cycle is presented. A one-dimensional mathematical model is developed using the flow governing thermodynamic equations based on a constant area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerant property calculations. The model has basically been used to determine the effect of the ejector geometry and operating conditions on the performance of the whole refrigeration system. The results show that the proposed model predicts ejector performance, entrainment ratio and the coefficient of performance of the system and their sensitivity to evaporating and generating temperature of the cascade refrigeration cycle. The simulated performance has been then compared with the available experimental data from the literature for validation.

Optimized Refrigerant Flow Rate and Dimensions of the Ejector Employed in a Modified Ejector Vapor Compression System

2020 ◽  
Vol 28 (04) ◽  
pp. 2050038
Author(s):  
Dishant Sharma ◽  
Gulshan Sachdeva ◽  
Dinesh Kumar Saini
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Proposed Model ◽  
Condenser Temperature ◽  
Vapor Compression System ◽  
Vapor Compression Cooling

This paper presents the analysis of a modified vapor compression cooling system which uses an ejector as an expansion device. Expanding refrigerant in an ejector enhances the refrigeration effect and reduces compressor work. Therefore, it yields a better coefficient of performance. Thermodynamic analysis of a constant area ejector model has been done to obtain primary dimensions of the ejector for given condenser and evaporator temperature and cooling capacity. The proposed model has been used to design the ejector for three refrigerants; R134a, R152a and R1234yf. The refrigerant flow rate and the diameters at various sections of the ejector have been obtained by doing numerical modeling in Engineering Equation Solver (EES). Refrigerant R1234yf demanded the highest diameter requirements at a fixed 5∘C evaporator temperature and 40∘C condenser temperature for a given range of cooling load. Both primary and secondary refrigerants flow rates are higher for R1234yf followed by R134a and then R152a.

Numerical Study of Ejector as an Expansion Device in Split-Type Air Conditioner

2013 ◽  
Vol 388 ◽  
pp. 101-105 ◽  
Author(s):  
Kasni Sumeru ◽  
Nasution Henry ◽  
Farid Nasir Ani
Keyword(s):  
Capillary Tube ◽  
Numerical Study ◽  
Geographical Area ◽  
Numerical Approach ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Air Conditioner ◽  
Constant Area ◽  
Condenser Temperature

This paper presents a numerical approach for determining the motive nozzle and constant-area of an ejector as an expansion device, based on cooling capacity of the split-type air conditioner using R22 as working fluid. The use of an ejector as an expansion device in split-type air conditioner can enhance the coefficient of performance (COP) system. Typically, the split-type air conditioner may be installed on the geographical area with moderate or high outdoor air temperature using capillary tube. For this reason, the motive nozzle and constant-area diameters of the ejector must be designed according to these conditions. The diameters of the ejector are crucial in improving the COP. The results showed that the motive nozzle diameter is constant (1.14 mm) with variations of the condenser temperature, whereas the constant-area diameter decreases as the condenser temperature increases.

Ejector Profile Modelling for Heat-Driven Ejector Refrigeration System Without Involving Shock

2015 ◽  
Author(s):  
Binoe E. Abuan ◽  
Menandro S. Berana
Keyword(s):  
Waste Heat ◽  
Fluid Dynamic ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Evaporator Temperature ◽  
Major Disadvantage ◽  
And Performance

Heat-driven ejector refrigeration system is one of the fastest emerging technologies in cooling applications for years. This is due to the fact that it can harness cooling capacity from waste heat sources at above 80 °C. Low coefficient of performance (compared to commercial vapor compression systems) is the major disadvantage of the said system, and thus it became a topic of research studies in the field of cooling. The work required by the compressor in a vapor compression cycle (VCC) can be eliminated by using waste heat from any available heat source. Although a relatively lower COP was obtained, the savings using the ejector refrigeration system can cover all the disadvantages and proved that this system can be actually helpful if implemented in the real working systems with waste heat. In this study, a mathematical model for determining ejector parameters and performance was developed and applied to a system where shock was tried to be avoided. The model was coded into a computer program to allow easier computation of the ejector geometric and thermo-fluid dynamic parameters with varying input data such as the refrigerant to be used, evaporator and condensing temperatures, entrainment ratio, and velocity of the fluid flows. An ejector refrigeration system using ammonia, propane, R22, R134a, R1234yf, and R245fa as refrigerants was simulated using the said model. A boiler or generator temperature of 90 °C, a condenser temperature of 40 °C, and a refrigerating capacity of 35kW were maintained for all the refrigerants; however, the evaporator temperature was varied within the range of −10 °C to 10 °C, depending on the behavior of the system. A combination of a short straight section and then a converging-diverging profile was used for the combined mixing section and diffuser to smoothly decelerate the fully mixed supersonic flow exiting the short mixing section and thereby avoid shock waves in the section. The resulting parameters including the ejector dimensions, pressure and Mach number were determined along the length of the ejector. For all the simulation runs, the fluids respond as expected and the expansion energy was utilized from the high pressure side of the ejector as shown in the trend of pressure along the length of the ejector. Ejector size varies a little for different refrigerants; the calculated range of length is from 0.14 m to 0.36 m — this range shows the compactness of the resulting ejectors. The results show that a VCC refrigeration system can be replaced by a heat-driven ejector refrigeration system with the ejector that was designed from the simulations. Since the two systems are designed to have the same refrigerating capacity and working temperatures, it can be projected that savings can be made by using the ejector system. The compactness of the ejector produced in the simulations show a good potential for this kind of refrigerating system to be manufactured and mass produced.

Performance investigation of a solar-driven ejector refrigeration cycle

2019 ◽  
Vol 16 (5) ◽  
pp. 625-635
Author(s):  
B. Saleh ◽  
Ayman A. Aly ◽  
M. Alsehli ◽  
M.M. Bassuoni ◽  
A. Elfasakhany
Keyword(s):  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Entrainment Ratio ◽  
Working Fluids ◽  
Content Type ◽  
Condenser Temperature ◽  
Working Parameters

Purpose This paper aims to investigate the performance and working fluids screening for an ejector refrigeration cycle (ERC) activated by solar energy. Several common and new hydrofluorocarbons, hydrocarbons, hydrofluoroolefins and hydrofluoroethers are proposed as refrigerants for the ERC to determine the most appropriate one. Design/methodology/approach The ejector performance is characterized by the ejector area ratio (EAR) and entrainment ratio (ω), while the cycle performance is described by the coefficient of performance (COP). The influences of many working parameters like the evaporator, condenser and generator temperatures on the ejector and cycle performances are investigated for all candidates as well. Findings The results indicate that the best ejector and cycle performances are attained with the highest critical temperature dry refrigerant, i.e. R601 under all studied working conditions. From the perspective of energy efficiency and environmental issues, R601 can be considered the most appropriate working fluid amongst all candidates. However, extra attention should be considered against its flammability. The maximum COP, the corresponding ω and the necessary EAR using R601 are 0.743, 1.02 and 15.5, respectively, with 25 ºC condenser temperature and the typical values for the rest operating conditions. Originality/value Many common and new hydrofluorocarbons, hydrocarbons, hydrofluoroolefins and hydrofluoroethers are suggested as working fluids for the ERC to determine the most appropriate one. The mixing process inside the ejector constant-area section is assumed constant-pressure process.

scholarly journals Design of an Ejector Working in Combined Ejector - Vapor Compressor Refrigeration Cycle

2021 ◽  
Vol 31.2 (149) ◽  
pp. 141-146
Keyword(s):  
Cooling Capacity ◽  
Area Ratio ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Vapor Compression Refrigeration Cycle ◽  
Condenser Temperature ◽  
Vapor Compression Refrigeration

In this paper, a calculation program is developed to design ejector working in a combined ejector – vapor compression refrigeration cycle. R134a is selected as the refrigerant for the ejector sub-cycle, and R410A is selected for the compressor sub-cycle. The effect of operating conditions and cooling capacity are examined. The results show that the area ratio increases with the increasing of generator temperature and intercooler temperature; and decreases with the increasing of condenser temperature and evaporator temperature. When the generator temperature, condenser temperature, intercooler temperature and evaporator temperature are 80°C, 34°C, 15°C, 0°C respectively, the area ratio is 8.55 and independent with cooling capacity. The design equations of significant dimensions based on operating conditions and cooling capacity are also introduced. The results show that R134a ejetor which is designed for simple ejector cycle is not suitable for combined cycle.

Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

Performance of Ejector Refrigeration Cycle for Automotive Air Conditioning

2016 ◽  
Vol 819 ◽  
pp. 202-206
Author(s):  
Reza Maziar ◽  
Kasni Sumeru ◽  
M.Y. Senawi ◽  
Farid Nasir Ani
Keyword(s):  
Compression Ratio ◽  
Air Conditioning ◽  
The Other ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Entrainment Ratio ◽  
Automotive Air Conditioning ◽  
Average Improvement

In this study, two experiments were performed, one with the conventional compression refrigeration cycle (CRC) and the other with an ejector refrigeration cycle (ERC). The CRC system for automotive air conditioning was designed, fabricated and experiments were conducted. The system was then retrofitted with an ejector as the expansion device and experiments were repeated for the ERC system. Calculations of the entrainment ratio, compressor compression ratio and coefficient of performance (COP) were made for each cycle. The calculations showed that ERC has some advantages over the CRC. In this study, an average improvement of 5% in COP has been obtained for the ERC compared with the CRC.

scholarly journals Investigation on the improvement of car air conditioning system performance using an ejector

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq
Keyword(s):  
System Performance ◽  
Test Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Compressor Work ◽  
R 134A

The purpose of this research is to know the improvement of car air conditioner system performance using an ejector. The study was conducted on a car engine with power 100 PS (74 kW) @ 5000 rpm. The test procedure is carried out under two conditions: the normal refrigeration cycle mode and the refrigeration cycle mode with the ejector. The working fluid used in the refrigeration cycle is R-134a. Performance data was measured on engine revolutions ranging from 1500 - 3000 rpm. Finally, the results showed that ejector usage on AC system generates an increase in the refrigeration effect and coefficient of performance (COP) of 25% and 22%, respectively. This has implications to better cooling capacity and compressor work that is lighter.

Comparison of Subcooling Effect of Water as a Refrigerant With the Current Refrigerants

2006 ◽  
Author(s):  
Ali Kilicarslan ◽  
Norbert Mu¨ller
Keyword(s):  
Computer Program ◽  
Performance Comparison ◽  
The Other ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Vapor Compression Refrigeration Cycle ◽  
Condenser Temperature ◽  
Vapor Compression Refrigeration ◽  
Compressor Efficiency

The performance comparison of water as a refrigerant (R718) with some prevailing refrigerants including R717, R290, R134a, R12, R22, and R152a is presented. A computer program simulating an actual vapor compression refrigeration cycle including subcooling was developed to calculate the coefficient of performances (COPs) for the different refrigerants. Evaporator temperatures above which water yields a better COP over the other refrigerants are investigated for subcooling case. The effect of degree of subcooling on the COPs is elaborated. For most of the refrigerants (R290, R134a, R12, R22, and R152a) the COP increases by around one percent (1%) per one Kelvin (1K) subcooling, while the COP for R718 and R717 increases by around 0.2 % and 0.5 % per one Kelvin (1K) subcooling. At constant evaporator temperature, increasing the degree of subcooling results in decrease of the relative COP gain of R718. R718 gives the highest relative COP increase at constant condenser temperature and polytropic efficiency. The effect of polytropic efficiency on the performance is also investigated. It is observed that the evaporator temperature range at which R718 presents a better COP than other refrigerants increases with increasing values of polytropic compressor efficiency if the degree of subcooling is kept constant.

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