Effect of Operational Parameters on a Novel Combined Cycle of Ejector Refrigeration Cycle and Kalina Cycle

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Candeniz Seckin
Keyword(s):  
Energy Content ◽  
Power Production ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Entrainment Ratio ◽  
Extensive Discussion ◽  
Kalina Cycle ◽  
Operation Conditions

A Kalina cycle is coupled to an ejector refrigeration cycle to generate power and refrigeration outputs, simultaneously. Ejector refrigeration cycle is driven by the heat which is extracted from a high-temperature/pressure stream of Kalina cycle working fluid since the energy content of this fluid stream is not directly utilized in power production in the Kalina cycle. Supplied heat to the proposed combined cycle is produced by combustion of biomethane which is obtained from anaerobic digestion of biomass, namely, food waste. System reactions to altering operation conditions (entrainment ratio, condenser pressure, evaporator pressure, and superheating degree) in terms of refrigeration production, power production, energy efficiency, exergy efficiency, and exergy of produced power and refrigeration are analyzed. The results are reported for R290, R134a, and R152a working fluids of the ejector refrigeration cycle and an extensive discussion of the results are provided. It is shown that the entrainment ratio strongly affects the thermal and exergy efficiency results. The highest thermal and exergy efficiency results are performed when R290 and R134a are used, whereas the lowest thermal and exergy efficiencies are obtained when R152a and R290 are used as the refrigerant, respectively.

scholarly journals Thermodynamic analysis and simulation of a new combined power and refrigeration cycle using artificial neural network

2011 ◽  
Vol 15 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Abdolreza Fazeli ◽  
Hossein Rezvantalab ◽  
Farshad Kowsary
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Heat Source ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Water Mixture ◽  
Artificial Neural

In this study, a new combined power and refrigeration cycle is proposed, which combines the Rankine and absorption refrigeration cycles. Using a binary ammonia-water mixture as the working fluid, this combined cycle produces both power and refrigeration output simultaneously by employing only one external heat source. In order to achieve the highest possible exergy efficiency, a secondary turbine is inserted to expand the hot weak solution leaving the boiler. Moreover, an artificial neural network (ANN) is used to simulate the thermodynamic properties and the relationship between the input thermodynamic variables on the cycle performance. It is shown that turbine inlet pressure, as well as heat source and refrigeration temperatures have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. In addition, the results of ANN are in excellent agreement with the mathematical simulation and cover a wider range for evaluation of cycle performance.

scholarly journals Exergy and Exergoeconomic Analysis of a Cogeneration Hybrid Solar Organic Rankine Cycle with Ejector

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 702
Author(s):  
Bourhan Tashtoush ◽  
Tatiana Morosuk ◽  
Jigar Chudasama
Keyword(s):  
Electrical Power ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Temperature And Pressure

Solar energy is utilized in a combined ejector refrigeration system with an organic Rankine cycle (ORC) to produce a cooling effect and generate electrical power. This study aims at increasing the utilized share of the collected solar thermal energy by inserting an ORC into the system. As the ejector refrigeration cycle reaches its maximum coefficient of performance (COP), the ORC starts working and generating electrical power. This electricity is used to run the circulating pumps and the control system, which makes the system autonomous. For the ejector refrigeration system, R134a refrigerant is selected as the working fluid for its performance characteristics and environmentally friendly nature. The COP of 0.53 was obtained for the ejector refrigeration cycle. The combined cycle of the solar ejector refrigeration and ORC is modeled in EBSILON Professional. Different parameters like generator temperature and pressure, condenser temperature and pressure, and entrainment ratio are studied, and the effect of these parameters on the cycle COP is investigated. Exergy, economic, and exergoeconomic analyses of the hybrid system are carried out to identify the thermodynamic and cost inefficiencies present in various components of the system.

A Totally Heat-Driven Refrigeration System Using Low-Temperature Heat Sources for Low-Temperature Applications

2019 ◽  
Vol 27 (02) ◽  
pp. 1950012 ◽  
Author(s):  
Zeynab Seyfouri ◽  
Mehran Ameri ◽  
Mozaffar Ali Mehrabian
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Water Mixture ◽  
Refrigeration System ◽  
Power Requirement ◽  
Temperature Heat

In the present study, a totally heat-driven refrigeration system is proposed and thermodynamically analyzed. This system uses a low-temperature heat source such as geothermal energy or solar energy to produce cooling at freezing temperatures. The proposed system comprises a Rankine cycle (RC) and a hybrid GAX (HGAX) refrigeration cycle, in which the RC provides the power requirement of the HGAX cycle. An ammonia–water mixture is used in both RC and HGAX cycles as the working fluid. A comparative study is conducted in which the proposed system is compared with two other systems using GAX cycle and/or a single stage cycle, as the refrigeration cycle. The study shows that the proposed system is preferred to produce cooling at temperatures from 2∘C to [Formula: see text]C. A detailed parametric analysis of the proposed system is carried out. The results of the analysis show that the system can produce cooling at [Formula: see text]C using a low-temperature heat source at 133.5∘C with the exergy efficiency of about 20% without any input power. By increasing the heat source temperature to 160∘C, an exergy efficiency of 25% can be achieved.

scholarly journals Energy and Cost Analysis and Optimization of a Geothermal-Based Cogeneration Cycle Using an Ammonia-Water Solution: Thermodynamic and Thermoeconomic Viewpoints

2020 ◽  
Vol 12 (2) ◽  
pp. 484 ◽  
Author(s):  
Nima Javanshir ◽  
Seyed Mahmoudi S. M. ◽  
M. Akbari Kordlar ◽  
Marc A. Rosen
Keyword(s):  
Water Solution ◽  
Unit Cost ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Cycle Performance ◽  
Working Fluid ◽  
Kalina Cycle ◽  
Ammonia Water ◽  
Total Product ◽  
Cogeneration Cycle

A cogeneration cycle for electric power and refrigeration, using an ammonia-water solution as a working fluid and the geothermal hot water as a heat source, is proposed and investigated. The system is a combination of a modified Kalina cycle (KC) which produces power and an absorption refrigeration cycle (ARC) that generates cooling. Geothermal water is supplied to both the KC boiler and the ARC generator. The system is analyzed from thermodynamic and economic viewpoints, utilizing Engineering Equation Solver (EES) software. In addition, a parametric study is carried out to evaluate the effects of decision parameters on the cycle performance. Furthermore, the system performance is optimized for either maximizing the exergy efficiency (EOD case) or minimizing the total product unit cost (COD case). In the EOD case the exergy efficiency and total product unit cost, respectively, are calculated as 34.7% and 15.8$/GJ. In the COD case the exergy efficiency and total product unit cost are calculated as 29.8% and 15.0$/GJ. In this case, the cooling unit cost, c p , c o o l i n g , and power unit cost, c p , p o w e r , are achieved as 3.9 and 11.1$/GJ. These values are 20.4% and 13.2% less than those obtained when the two products are produced separately by the ARC and KC, respectively. The thermoeconomic analysis identifies the more important components, such as the turbine and absorbers, for modification to improve the cost-effectiveness of the system.

Analysis of a Combined Power and Refrigeration Cycle Working on Solar Energy

2008 ◽  
Author(s):  
Bijan Kumar Mandal ◽  
Kousik Sadhukhan ◽  
Achin Kumar Chowdhuri ◽  
Arup Jyoti Bhowal
Keyword(s):  
Solar Energy ◽  
Working Conditions ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Cooling Effect ◽  
Second Law ◽  
Carnot Cycle ◽  
Refrigeration Cycle ◽  
Water Mixture ◽  
The Ideal

Thermodynamic analysis of a combined cycle producing power and refrigeration (cooling) effect simultaneously using solar energy has been analyzed. The working substance of the cycle is a binary mixture of ammonia and water. The effect of variation of absorber pressure, boiler pressure, boiler temperature and superheater temperature on the turbine work, refrigeration (cooling) effect and net output has been investigated. For different conditions of the above variables, the first law efficiency, the second law efficiency and the exergy efficiency of the cycle have been investigated. Since the ammonia water mixture boils at varying temperatures, Lorenz cycle instead of Carnot cycle is considered as the ideal cycle for this analysis. It is observed that the first law and the second law efficiencies are maximum under the same working conditions, but the exergy efficiency is maximum at some other working conditions. The maximum values of the first law, the second law and the exergy efficiencies are found to be 21.72%, 27.30% and 62.53% respectively.

Investigation of the Liquid–Vapor Separator Efficiency on the Performance of the Ejector Used as an Expansion Device in the Vapor-Compression Refrigeration Cycle

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Ayşe Uğurcan Atmaca ◽  
Aytunç Erek ◽  
Orhan Ekren
Keyword(s):  
Performance Improvement ◽  
Separation Efficiency ◽  
Area Ratio ◽  
Refrigeration Cycle ◽  
Entrainment Ratio ◽  
Operation Conditions ◽  
Vapor Compression Refrigeration Cycle ◽  
The Difference ◽  
Ejector Cycle ◽  
Liquid Vapor

Abstract Ejector expansion refrigeration cycle with reference to the constant pressure mixing theory is investigated to display the effects of the liquid–vapor separator efficiency on the performance, entrainment ratio, and area ratio at various operation conditions. Reversible ejector assumption is used for the highest theoretical performance limit, whereas efficiency of the liquid–vapor separator and all ejector components is added to the model to calculate more realistic performance improvement potentials. R1234yf and R1234ze(E) having low global warming potential values are used in the analyses. Zero-dimensional thermodynamic models are constructed applying the conservation equations between the inlets and outlets of the refrigeration cycle and ejector components. Percentage performance decrease is higher when the mixing section and the separator efficiency is added to the model at higher condenser temperatures compared with the lower evaporator temperatures according to the investigated operation ranges. Vapor and liquid separation efficiency affects not only the performance but also the design of the ejector although it is an external component since it has influence on the area ratio and entrainment ratio. Finally, the difference between the percentage performance improvement of the reversible ejector cycle and the realistic ejector cycle including the separator and ejector components efficiencies is as high as 35% at the highest investigated condenser temperature for R1234yf.

scholarly journals Exergy Analysis of Kalina and Kalina Flash Cycles Driven by Renewable Energy

2020 ◽  
Vol 10 (5) ◽  
pp. 1813
Author(s):  
Kyoung Hoon Kim ◽  
Hyung Jong Ko ◽  
Chul Ho Han
Keyword(s):  
Exergy Analysis ◽  
Power Production ◽  
Ammonia Concentration ◽  
Exergy Efficiency ◽  
Low Grade ◽  
Heat Sources ◽  
Exergy Destruction ◽  
Kalina Cycle ◽  
Low Grade Heat ◽  
Exergy Performance

The Kalina cycle (KC) has been recognized as one of the most efficient conversion systems of low-grade heat sources. The Kalina flash cycle (KFC) is a recently proposed novel cycle which is equipped with an additional flash process to the KC. In this study, the exergy performance of KC and KFC driven by a low-grade heat source are investigated comparatively. The dependence of the exergy destruction at each component as well as the system’s exergy efficiency on ammonia concentration, separator pressure and, additionally, flash pressure for KFC, are systematically investigated. Results showed that KFC can be optimized with respect to flash pressure on the base of exergy efficiency, and the component where largest exergy destruction occurs varies for different separator pressure and ammonia fraction in both systems. It is also shown that the maxima of net power production and exergy efficiency in KFC with optimal flash pressure are superior to those in KC.

Energy and Exergy Analysis of an Organic Rankine Cycle used for Ylang-Ylang Essential Oil Distillery Waste Heat Recovery for Power Production in Anjouan Island

2021 ◽  
Vol 1 (1) ◽  
pp. 15-24
Author(s):  
Malik El’Houyoun Ahamadi ◽  
Hery T. Rakotondramiarana
Keyword(s):  
Energy Efficiency ◽  
Essential Oil ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Power Production ◽  
Exergy Efficiency ◽  
Inlet Pressure ◽  
Working Fluid ◽  
Energy And Exergy ◽  
Residual Heat

In the ylang-ylang essential oil distillers in Anjouan Island, the used energy is 100% firewood biomass. A large amount of this energy is dissipated in the environment just in the combustion chamber itself. As it turns out, the flue gases in this process take away the most part of it. Thus, in a process of energy efficiency of stills, the present work aims at assessing the possibility to convert the residual heat from the process into electricity. For that purpose, energy and exergy modeling of an organic Rankine cycle was implemented. It was found that a large amount of exergy is destroyed in the evaporator. Similarly, it emerges that the exergy efficiency of the cycle depends on the inlet temperatures of the exhaust gases in the evaporator and on the inlet pressure of the working fluid in the turbine, and that it is much better for low exhaust gas temperatures. At these low values of gas temperatures, it appears that the improvement in exergy efficiency and energy efficiency are linked to the increase in the inlet pressure of the working fluid in the turbine. It follows from the obtained results that the discharged hot water and the residual heat of gases having temperatures ranging from 180°C to 300 °C, could be used for power production which can reach electrical powers between 1.4kW and 4.5kW  

On Evaluating Efficiency of a Combined Power and Cooling Cycle

2003 ◽  
Vol 125 (3) ◽  
pp. 221-227 ◽  
Author(s):  
Sanjay Vijayaraghavan ◽  
D. Y. Goswami
Keyword(s):  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Maximum Efficiency ◽  
Second Law ◽  
Refrigeration Cycle ◽  
Absorption Refrigeration ◽  
Cooling Cycle ◽  
Reduced Gradient ◽  
Generalized Reduced Gradient

A combined power and cooling cycle is being investigated. The cycle is a combination of the Rankine cycle and an absorption refrigeration cycle. Evaluating the efficiency of this cycle is made difficult by the fact that there are two different simultaneous outputs, namely power and refrigeration. An efficiency expression has to appropriately weigh the cooling component in order to allow comparison of this cycle with other cycles. This paper develops several expressions for the first law, second law and exergy efficiency definitions for the combined cycle based on existing definitions in the literature. Some of the developed equations have been recommended for use over others, depending on the comparison being made. Finally, some of these definitions have been applied to the cycle and the performance of the cycle optimized for maximum efficiency. A Generalized Reduced Gradient (GRG) method was used to perform the optimization. The results of these optimizations are presented and discussed.

scholarly journals Evaluation and Optimization of the Annual Performance of a Novel Tri-Generation System Driven by Geothermal Brine in Off-Design Conditions

2020 ◽  
Vol 10 (18) ◽  
pp. 6532
Author(s):  
Mehri Akbari Kordlar ◽  
Florian Heberle ◽  
Dieter Brüggemann
Keyword(s):  
Exergy Efficiency ◽  
Working Fluid ◽  
Exergy Destruction ◽  
Operational Parameters ◽  
Generation System ◽  
Geothermal Resources ◽  
Kalina Cycle ◽  
Destruction Rate ◽  
Heating And Cooling ◽  
The Difference

The difference in heating or cooling to power ratio between required demands for district networks and the proposed tri-generation system is the most challenging issue of the system configuration and design. In this work, an adjustable, novel tri-generation system driven by geothermal resources is proposed to supply the thermal energies of a specific district network depending on ambient temperature in Germany. The tri-generation system is a combination of a modified absorption refrigeration cycle and a Kalina cycle using NH3-H2O mixture as a working fluid for the whole tri-generation system. A sensitive analysis of off-design conditions is carried out to study the effect of operational parameters on the system performances prior to optimizing its performance. The simulation show that the system is able to cover required heating and cooling demands. The optimization is applied considering the maximum exergy efficiency (scenario 1) and minimum total exergy destruction rate (scenario 2). The optimization results show that the maximum mean exergy efficiency in scenario 1 is achieved as 44.67% at the expense of 14.52% increase in the total exergy destruction rate in scenario 2. The minimum mean total exergy destruction rate in scenario 2 is calculated as 2980 kW at the expense of 8.32% decrease in the exergy efficiency in scenario 1.

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