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

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.

2012 ◽  
Vol 326-328 ◽  
pp. 641-646 ◽  
Author(s):  
Nahla Bouaziz ◽  
D. Lounissi ◽  
Lakdar Kairouani ◽  
M. El Ganaoui

The objective of this work is to present an exergy analysis of a novel absorption configuration using water-ammonia as working fluid. The proposed configuration operates at three pressure levels. The absorber is at an intermediate pressure (Pint). A thermodynamic model based on the mass energy and exergy balances is developed for this purpose. The parameters analyzed are the refrigeration systems performance (COP), the exergy efficiency, the global exergy destruction in the system, the exergy destruction and the irreversibility in different components. The effects of generator, absorber, condenser and evaporator on the performance of the system are examined. Numerical results highlight the great importance of the intermediate pressure on the performance of the system and specially on reducing the operating generator temperature. Consequently, the intermediate pressure is directly responsible on the adaptability of the proposed cooling absorption cycle to low enthalpy sources.


2015 ◽  
Vol 787 ◽  
pp. 32-36 ◽  
Author(s):  
V.Boopathi Raja ◽  
V. Shanmugam

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.


2020 ◽  
Vol 38 (6) ◽  
pp. 2521-2540
Author(s):  
Juliana Isabel Saucedo Velázquez ◽  
Wilfrido Rivera Gómez Franco ◽  
Efraín Gómez-Arias ◽  
Geydy Gutiérrez Urueta

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.


2018 ◽  
Vol 157 ◽  
pp. 351-363 ◽  
Author(s):  
Muhammad Shoaib Ahmed Khan ◽  
Abdul Waheed Badar ◽  
Tariq Talha ◽  
Muhammad Wajahat Khan ◽  
Fahad Sarfraz Butt

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