Exergy analysis: Parametric study on lithium bromide—water absorption refrigeration systems

2007 ◽  
Vol 221 (11) ◽  
pp. 1345-1351 ◽  
Author(s):  
K Sedighi ◽  
M Farhadi ◽  
M Liaghi
Keyword(s):  
Exergy Analysis ◽  
Water Solution ◽  
Lithium Bromide ◽  
Cooling Water ◽  
Coefficient Of Performance ◽  
Absorption Refrigeration ◽  
Exergetic Efficiency ◽  
Evaporator Temperature ◽  
Cooling Water Temperature ◽  
Single Effect

In the current study, an exergy analysis of a single-effect absorption refrigeration cycle using lithium bromide-water solution is carried out. The cycle has been analysed by considering the mass and energy conservation based on the first and second laws of thermodynamics. This analysis provides a detailed information on the effect of different parameters on the system performance. The coefficient of performance (COP), exergetic efficiency (ECOP), and exergy destruction are determined. The results show that a reduction in cooling water temperature caused an improvement in the COP and ECOP. Increasing the evaporator temperature has also improved the COP, but it caused a reduction in the ECOP of the system. Also it can be seen that the parameters' variation at the solution side has a more significant effect on cycle performances.

scholarly journals Energy and exergy analysis of vapour compression refrigeration system using selected eco-friendly hydrocarbon refrigerants enhanced with tio2-nanoparticle

2017 ◽  
Vol 6 (4) ◽  
pp. 91 ◽  
Author(s):  
Luke Ajuka ◽  
Moradeyo Odunfa ◽  
Olayinka Ohunakin ◽  
Miracle Oyewola
Keyword(s):  
Power Consumption ◽  
Exergy Analysis ◽  
Capillary Tube ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Exergetic Efficiency ◽  
Evaporator Temperature ◽  
Energy And Exergy ◽  
Nano Lubricant ◽  
Energy And Exergy Analysis

The experimental study investigated the energy and exergy performance of a domestic refrigerator using eco-friendly hydrocarbon refrigerants R600a and LPG (R290/R600a: 50%/50%) at 0, 0.05, 0.15 and 0.3wt % concentrations of 15nm particle size of TiO2 nano-lubricant, and R134a. The effects of evaporator temperature on power consumption, coefficients of performance, exergetic efficiency and efficiency defects in the compressor, condenser, capillary tube and evaporator of the system were examined. The results showed that LPG + TiO2 (0.15wt %) and R600a + TiO2 (0. 15wt %) had the best of performances with an average of 27.6% and 14.3% higher coefficient of Performance, 34.6% and 35.15% lower power consumption, 13.8% and 17.53% higher exergetic efficiency, a total exergetic defect of 45.8% and 64.7% lower compared to R134a. The exergetic defects in the evaporator, compressor, condenser, and capillary tube were 38.27% and 35.5%, 49.19% and 55.56%, 29.7% and 33.7%, 39.1% and 73.8% lower in the system when compared to R134a respectively. Generally, the refrigerants with nano-lubricant mixture gave better results with an appreciable reduction in the exergy defect in the compressor than the pure refrigerants, and LPG + TiO2 (0. 15wt %) gave the best result in the refrigeration system based on energy and exergy analysis.

A theoretical and experimental study of a novel recompression absorption refrigeration cycle

2001 ◽  
Vol 215 (1) ◽  
pp. 75-87 ◽  
Author(s):  
I. W. Eames ◽  
S Wu
Keyword(s):  
Experimental Study ◽  
Theoretical Study ◽  
Lithium Bromide ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Absorption Refrigeration ◽  
Corrosion Rates ◽  
Steam Ejector ◽  
Single Effect ◽  
Absorption Cycle

This paper describes a novel vapour absorption refrigeration cycle which uses a steam ejector to enhance the concentration process of the cycle. The paper provides a complete description of the cycle and presents the results of a theoretical study before going on to describe and evaluate the outcomes of an experimental programme. The results of this investigation showed that with the addition of a steam ejector as described the coefficient of performance (COP) of the single-effect lithium bromide absorption cycle can be increased from about 0.7 to at least 1.0 without any increase in corrosion rates often associated with high temperature vapour generators used in conventional machines of this type.

Analysis of Aqueous Lithium Bromide Absorption Refrigeration Systems

2021 ◽  
pp. 1-18
Author(s):  
Dongchuan You ◽  
Hameed Metghalchi
Keyword(s):  
Lithium Bromide ◽  
Double Effect ◽  
Environmental Safety ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Solution Energy ◽  
Exit Temperature ◽  
Single Effect ◽  
Aqueous Lithium Bromide

Abstract Aqueous lithium bromide absorption refrigeration systems have been studied in recent years and their advantages like environmental safety and utilization of low-grade energy have been proved. Research on improving their performance has been increasing lately. In this paper, single effect and parallel flow double-effect aqueous lithium bromide absorption refrigeration systems have been studied. Mass, energy, entropy and exergy balances have been used to model the absorption refrigeration systems. Parametric studies have been done to investigate effects of cooling load, evaporator exit temperature, condenser exit temperature, generator vapor exit temperature, absorber exit temperature, solution energy exchanger effectiveness on the performance of the system. The analyses show coefficient of performance and exergetic efficiency of double-effect absorption refrigeration is higher than those of a single-effect refrigeration. The effect of other parameters on performance of both single and double-effect systems have been described in detail in the article.

scholarly journals Thermodynamic Evaluation of LiCl-H2O and LiBr-H2O Absorption Refrigeration Systems Based on a Novel Model and Algorithm

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3037 ◽  
Author(s):  
Ren ◽  
Qian ◽  
Yao ◽  
Gan ◽  
Zhang
Keyword(s):  
Cooling Water ◽  
Cooling Capacity ◽  
Calculation Model ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Thermodynamic Evaluation ◽  
Absorption Refrigeration ◽  
Exergetic Efficiency ◽  
Absorption Chillers

An absorption refrigeration system (ARS) is an alternative to the conventional mechanical compression system for cold production. This study developed a novel calculation model using the Matlab language for the thermodynamic analysis of ARS. It was found to be reliable in LiCl-H2O and LiBr-H2O ARS simulations and the parametric study was performed in detail. Moreover, two 50 kW water-cooled single effect absorption chillers were simply designed to analyze their off-design behaviors. The results indicate that LiCl-H2O ARS had a higher coefficient of performance (COP) and exergetic efficiency, particularly in the lower generator or higher condenser temperature conditions, but it operated more restrictively due to crystallization. The off-design analyses revealed that the preponderant performance of LiCl-H2O ARS was mainly due to its better solution properties because the temperature of each component was almost the same for both chillers in the operation. The optimum inlet temperature of hot water for LiCl-H2O (83 °C) was lower than that of LiBr-H2O (98 °C). The cooling water inlet temperature should be controlled within 41 °C, otherwise the performances are discounted heavily. The COP and cooling capacity could be improved by increasing the temperature of hot water or chilled water properly, contrary to the exergetic efficiency.

Exergy calculation of lithium bromide-water solution and its application in the exergetic evaluation of absorption refrigeration systems LiBr-H2O

2010 ◽  
Vol 36 (2) ◽  
pp. 166-181 ◽  
Author(s):  
Reynaldo Palacios-Bereche ◽  
R. Gonzales ◽  
S. A. Nebra
Keyword(s):  
Water Solution ◽  
Lithium Bromide ◽  
Absorption Refrigeration

EXERGY ANALYSIS OF A LiBr–H2O VAPOR ABSORPTION REFRIGERATION PLANT: A CASE STUDY

2014 ◽  
Vol 22 (02) ◽  
pp. 1450010 ◽  
Author(s):  
SANJEEV ANAND ◽  
ANKUSH GUPTA ◽  
SUDHIR KUMAR TYAGI
Keyword(s):  
Performance Optimization ◽  
Exergy Analysis ◽  
Heat Rate ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Absorption Refrigeration ◽  
Actual System ◽  
Evaporator Temperature ◽  
Vapor Absorption ◽  
Vapor Absorption Refrigeration

This communication presents the energy and exergy analysis of an actual double effect steam powered LiBr – H 2 O vapor absorption refrigeration plant. Exergy loss, COP, exergy efficiency and heat rate for each component of the system are calculated. The effect of generator as well as evaporator temperature on the COP and exergy efficiency is evaluated and it is found that the irreversibility rate is highest in the generator while it is found to be the lowest in the case of absorber and condenser. It is also found that the COP of the system increases with the increase in the evaporator temperature while it is found to be reverse in case of exergy efficiency. Results revealed that average exergy loss is highest in the generator as compared to other components. The results obtained are helpful for designers to bring changes in the actual system for performance optimization and less wastage of energy. The study clearly explain the operational and maintenance problems in the machine and point out the areas of energy wastage which the operational engineer should look into for the optimum operation of the plant.

Environment Friendly Mixed Refrigerant to Replace R-134a in a VCR System with Exergy Analysis

2014 ◽  
Vol 984-985 ◽  
pp. 1174-1179
Author(s):  
N. Austin ◽  
P.M. Diaz ◽  
D.S. Manoj Abraham ◽  
N. Kanthavelkumaran
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Ozone Depletion ◽  
Exergy Analysis ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Evaporator Temperature ◽  
Environment Friendly ◽  
A Charge ◽  
Vapour Compression

Study on environment friendly mixed refrigerant to replace R134a in vapour compression refrigeration (VCR) System. The mixed refrigerants investigated are propane (R290), butane (R600), isobutene (R600a) and R134a. Even though the ozone depletion potentials of R134a relative to CFC-11 are very low; the global warming potentials are extremely high and also expensive. For this reason, the production and use of R134a will be terminated in the near future. Hydrocarbons are free from ozone depletion potential and have negligible global warming potential. The results showed that, mixed refrigerant with charge of 80 g satisfy the required freezer air temperature when R134a with a charge of 110 g is used as refrigerant. The actual COP of refrigerator using mixed refrigerant was almost nearer that of the system using R134a as refrigerant. The coefficient of performance of the vapour compression refrigeration system using mixed refrigerant MR-3 [R134a/R290/ R600a/ R600 (20/35/40/5)] is having very close value with R134a and the Global warming potential of MR-3 is negligible when compared with R134a. Hence the mixed refrigerant MR-3 is chosen as an environmental friendly alternate refrigerant to R134a. The exergy analysis of the vapour compression refrigeration system using R134a and all the above mixtures are investigated. The effect of evaporator temperature on exergy efficiency and exergy destruction ratio of the system are experimentally studied. The exergy defect in the compressor, condenser, expansion device and evaporator are also obtained. Key words: R134a, Mixed refrigerant, Chlorofluorocarbons, Propane, Butane, Isobutene, REFPROP, COP, ODP, GWP, Exergy, VCR System.

Transient Modeling of a Lithium Bromide – Water Absorption Chiller

2013 ◽  
Vol 388 ◽  
pp. 83-90 ◽  
Author(s):  
Ang Li ◽  
Wai Soong Loh ◽  
Kim Choon Ng
Keyword(s):  
Water Absorption ◽  
Cooling Tower ◽  
Lithium Bromide ◽  
Cooling Water ◽  
Coefficient Of Performance ◽  
Absorption Chiller ◽  
Transient Model ◽  
Operation Conditions ◽  
Operation Process ◽  
Main Components

This article presents a thermodynamic framework for a lithium bromide – water absorption chiller, in which a transient model is developed to simulate the operation process. Local energy and mass balance within the main components like absorber, regenerator, condenser, evaporator and solution heat exchanger is respected to investigate the behavior of the chiller. Experimental correlations are used to predict heat transfer of the related working fluids. The cooling water is set to typical cooling tower conditions of tropical countries such as Singapore. The coefficient of performance (COP) is evaluated against a range of heat source temperatures from 75oC to 100oC. The results indicate the operation conditions of the chiller at its maximum COP is 95oC to 100oC.

Sign in / Sign up

Export Citation Format

Share Document