scholarly journals Analysis of Hybrid Ejector Absorption Cooling System

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Doniazed Sioud ◽  
Ahmed Bellagi
Keyword(s):  
Water Cycle ◽  
Cooling System ◽  
Lithium Bromide ◽  
Steam Pressure ◽  
Entrainment Ratio ◽  
Evaporator Temperature ◽  
Condenser Temperature ◽  
Single Effect ◽  
Absorption Cooling System ◽  
Hybrid Cycle

In this paper, a hybrid ejector single-effect lithium-bromide water cycle is theoretically investigated. The system is a conventional single-effect cycle activated by an external steam-ejector loop. A mathematical model of the whole system is developed. Simulations are carried out to study the effect of the major parameters of the hybrid cycle on its performances and in comparison with the conventional cycle. The ejector performance is also investigated. Results show that the entrainment ratio rises with steam pressure and condenser temperature, while it decreases with increasing generator temperature. The effect of the evaporator temperature on ejector performance is negligible. It is shown also that the hybrid cycle exhibits better performances than the corresponding basic cycle. However, the performance improvement is limited to a specific range of the operating parameters. Outside this range, the hybrid system behaves similar to a conventional cycle. Inside this range, the COP increases, reaches a maximum, and then decreases and rejoins the behavior of the basic cycle. The maximum COP, which can be as large as that of a conventional double-effect cycle, about 1, is obtained at lower temperatures than in the case of single-effect cycles.

scholarly journals Thermodynamic Analysis of a Solar Combined Ejector Absorption Cooling System

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Doniazed Sioud ◽  
Raoudha Garma ◽  
Ahmed Bellagi
Keyword(s):  
Cooling System ◽  
Lithium Bromide ◽  
Cooling Water ◽  
Double Effect ◽  
Cycle Performance ◽  
Working Fluid ◽  
Absorption Cooling ◽  
Single Effect ◽  
Absorption Cycle ◽  
Absorption Cooling System

The objective of this paper is to investigate theoretically a solar driven 60 kW absorption cooling system. The system is constituted of a combined ejector single-effect absorption cycle coupled with a linear Fresnel solar concentrator and using water/lithium bromide as working fluid. The combined ejector single-effect absorption cycle exhibits high performances, almost equal to that of double-effect absorption device. However, higher driving heat temperatures are required than in the case of conventional single-effect machines. A mathematical model is set up to analyze the optical performance of the linear Fresnel concentrator. Simulations are carried out to study the overall system performance COPsystem and the performances of the combined absorption machine COPcycle for generator driving temperatures and pressures in the ranges 180°C – 210°C and 198 kPa – 270 kPa, respectively. Further, the effect of operating parameters such as the cooling medium and chilled water temperatures is investigated. A maximum cycle performance of 1.03 is found for a generator pressure of 272 kPa and chilled and cooling water temperatures of 7°C and 25°C, respectively. A case study is investigated for a typical summer Tunisian day, from 8:00 to 18:00. The effect of ambient temperature and solar radiation on cycle and system performances is simulated. The optical performances of the concentrator are also analyzed. Simulation results show that between 11:00 and 14:00 the collector efficiency is 0.61 and that the COPcycle reaches values always higher than 0.9 and the COPsystem is larger than 0.55. Globally the performances of the investigated cycle are similar to those of double-effect conventional absorption system.

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.

Experimental Analysis of Newly Designed Solar Assisted Single Effect Absorption Cooling System of 5.25 kW Cooling Capacity for Domestic Use

2015 ◽  
Vol 787 ◽  
pp. 32-36 ◽  
Author(s):  
V.Boopathi Raja ◽  
V. Shanmugam
Keyword(s):  
Cooling System ◽  
Cooling Capacity ◽  
Hot Water ◽  
Operational Parameters ◽  
Water Storage Tank ◽  
Absorption Cooling ◽  
Domestic Use ◽  
Single Effect ◽  
Absorption Cooling System ◽  
Vapour Compression

Many research studies have been carried out to develop small capacity absorption cooling systems as an alternative to conventional vapour compression refrigeration (VCR) systems with respect to performance and economic aspects. The aim of this work is to design a solar assisted single effect absorption cooling system of 5.25 kW cooling capacity to cool a room having floor area of 15 m2. Based on the design, an experimental setup is constructed and operated by supplying heat to the generator using solar energy. The performance analysis of the cooling system is carried out by measuring the various operational parameters. The minimum cooling temperature of 16°C is observed in the evaporator and maximum COP of 0.9 is obtained when the hot water storage tank reaches 90°C. As per this new design, the operational cost is minimized and the COP obtained is slightly higher when compared to that of earlier similar works.

Performance of a Water Ammonia Absorption System Operating at Three Pressure Levels

2011 ◽  
Vol 312-315 ◽  
pp. 947-952 ◽  
Author(s):  
Nahla Bouaziz ◽  
R. Ben Iffa ◽  
Lakdar Kairouani ◽  
Salahs Chikh ◽  
Rachid Bennacer
Keyword(s):  
Cooling System ◽  
Single Stage ◽  
Working Fluid ◽  
The Novel ◽  
Evaporator Temperature ◽  
Intermediate Pressure ◽  
Condenser Temperature ◽  
Conventional Machine ◽  
Ammonia Absorption ◽  
Set Up

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

Evaluation of the cooling potential for a single effect absorption cooling system in the PR2 well of Cerritos Colorados geothermal field, Mexico

2020 ◽  
Vol 38 (6) ◽  
pp. 2521-2540
Author(s):  
Juliana Isabel Saucedo Velázquez ◽  
Wilfrido Rivera Gómez Franco ◽  
Efraín Gómez-Arias ◽  
Geydy Gutiérrez Urueta
Keyword(s):  
Cooling System ◽  
Geothermal Field ◽  
Cooling Systems ◽  
Absorption Cooling ◽  
Different Depths ◽  
Single Effect ◽  
Typical Day ◽  
Conventional Cooling ◽  
Conventional Systems ◽  
Absorption Cooling System

Conventional cooling systems consume a high percentage of the world’s total electricity generation. Because absorption cooling systems can be mainly operated with thermal energy, they can be used to reduce such percentage. In the present paper, an analysis is carried out to determine the cooling potential that can be obtained from a geothermal well in a location of Mexico by using a single-stage absorption cooling system. The analysis has been carried out taking into account the desired cooling temperature, the ambient temperature, and the temperatures at different depths of the wells for a typical day of every season of the year. The results showed that, for a fixed generation temperature, a maximum cooling potential as big as 71,594 GW, 70,649 GW, 71,164 GW, 70,859 GW could be obtained in Winter, Spring, Summer, and Autumn, respectively. Using the temperatures obtained from the well, for a fixed depth, the results show that higher values are obtained in spring and summer. From the analysis, it is clear that absorption systems operating with geothermal energy could be an excellent alternative to reduce the electricity consumed by conventional systems.

Configuration based modeling and performance analysis of single effect solar absorption cooling system in TRNSYS

2018 ◽  
Vol 157 ◽  
pp. 351-363 ◽  
Author(s):  
Muhammad Shoaib Ahmed Khan ◽  
Abdul Waheed Badar ◽  
Tariq Talha ◽  
Muhammad Wajahat Khan ◽  
Fahad Sarfraz Butt
Keyword(s):  
Performance Analysis ◽  
Cooling System ◽  
Solar Absorption ◽  
Absorption Cooling ◽  
Single Effect ◽  
And Performance ◽  
Solar Absorption Cooling ◽  
Absorption Cooling System
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