Power optimization of an endoreversible closed intercooled regenerated Brayton-cycle coupled to variable-temperature heat-reservoirs

Wang, Wenhua; Chen, Lingen; Sun, Fengrui; Chen, Wu

doi:10.1016/j.apenergy.2004.08.007

Cited by 26 publications

(13 citation statements)

References 23 publications

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“…Because of heat resistance, the temperature T 3 should be higher than T H , and the temperature T 6 should be lower than T L , as shown in Figure 1. It is often assumed that the heat transfer between the working substance and the heat reservoirs obeys the Newtonian law [18,32], such that the amount of heat transferred in the two iso-magnetic field processes, Q H and Q L , may be expressed as [33,34]:…”

Section: Expressions For Several Important Parametersmentioning

confidence: 99%

Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

Wang

2012

Sci. China Phys. Mech. Astron.

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A model of the irreversible regenerative Brayton refrigeration cycle working with paramagnetic materials is established, in which the regeneration problem in two constant-magnetic field processes and the irreversibility in two adiabatic processes are considered synthetically. Expressions for the COP, cooling rate, power input, the minimum ratio of the two magnetic fields, etc., are derived. It is found that the influence of the irreversibility and the regeneration on the main performance parameters of the magnetic Brayton refrigerator is remarkable. It is important that we have obtained several optimal criteria, which may provide some theoretical basis for the optimal design and operation of the Brayton refrigerator. The results obtained in the paper can provide some new theoretical information for the optimal design and performance improvement of real Brayton refrigerators. paramagnetic salt, Brayton refrigeration, irreversibility, regeneration, performance characteristics, optimum criterion PACS number(s): 75.30.Sg, 07.20.Mc Citation:Wang H, Wu G X. Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle.The conventional vapor compression refrigerator widely used in many fields has many disadvantages such as the energy efficiency being difficult to improve further, the gases used enhance the greenhouse effect or deplete the ozone layer, and so on. Magnetic refrigeration is an environment-safe refrigeration technology which has been studied for a long time [1][2][3][4][5] for its potential use in refrigeration cycles as an alternative to gases, especially at low temperatures. As more and more attention is paid to environmental protection and investigations on room-temperature magnetic refrigeration materials, magnetic refrigeration theory and technology have had a great development [6-11]. Optimal analysis and design of magnetic refrigeration cycles [12][13][14][15][16][17] have become one of the interesting research subjects for people working in thermodynamics and statistical physics. Moreover, most of the literature has only researched the optimal performance characteristics of a magnetic Stirling [18][19][20] or Ericsson refrigeration cycle [21][22][23][24].The magnetic Brayton refrigeration cycle is one of the important refrigeration cycles and has some distinct merits that are noteworthy in the research and manufacture of roomtemperature magnetic refrigerators. Although the analysis and design of some magnetic Brayton refrigeration cycles has been undertaken [25][26][27], research on the performance of the magnetic Brayton refrigeration cycle is relatively rare [28][29][30]. In fact, the magnetic Brayton refrigeration cycle is also a significant regenerative cycle. Therefore, it is necessary to consider both the regenerative and other irreversible effects on a magnetic Brayton refrigeration cycle.In the article, we investigate the main characteristics of an irreversible regenerative magnetic Brayton refrigeration cycle. The paper is organized as ...

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Section: Expressions For Several Important Parametersmentioning

confidence: 99%

Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

Wang

2012

Sci. China Phys. Mech. Astron.

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“…They found momentous reduction in entropy generation rate with a little detriment in power output. The optimal operating conditions of endoreversible and irreversible Brayton heat engines are studied by Wang et al [16,17] and Kaushik et al [11,12] respectively. Nevertheless, two or more objective functions must be optimized at the same time.…”

Section: Introductionmentioning

confidence: 99%

“…Intercooler compression, reheater expansion, regeneration and isothermal heat addition are few amendments [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] which have been acknowledged theoretically to upgrade the performance of Brayton cycles. In recent years, significant consideration has been given to single objective optimization of Brayton heat engine through range of objective functions including power output [14][15][16][17], power density [20], thermal efficiency [5,6], ecological function [13,18,19], entropy generation [7,8] and thermo-economic function [9,10]. Wu [1] studied an endoreversible Brayton cycle and optimized power output with respect to working fluid temperature.…”

Section: Introductionmentioning

confidence: 99%

Multi-objective thermodynamic optimization of an irreversible regenerative Brayton cycle using evolutionary algorithm and decision making

Kumar

Kaushik

Kumar

et al. 2016

Ain Shams Engineering Journal

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Brayton heat engine model is developed in MATLAB simulink environment and thermodynamic optimization based on finite time thermodynamic analysis along with multiple criteria is implemented. The proposed work investigates optimal values of various decision variables that simultaneously optimize power output, thermal efficiency and ecological function using evolutionary algorithm based on NSGA-II. Pareto optimal frontier between triple and dual objectives is obtained and best optimal value is selected using Fuzzy, TOPSIS, LINMAP and Shannon's entropy decision making methods. Triple objective evolutionary approach applied to the proposed model gives power output, thermal efficiency, ecological function as (53.89 kW, 0.1611, À142 kW) which are 29.78%, 25.86% and 21.13% lower in comparison with reversible system. Furthermore, the present study reflects the effect of various heat capacitance rates and component efficiencies on triple objectives in graphical custom. Finally, with the aim of error investigation, average and maximum errors of obtained results are computed. Ó 2015 Faculty of Engineering, Ain Shams University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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“…An important method for analyzing performance of real engineering cycles is provided by a new discipline in modern thermodynamics caused by the development of finite‐time thermodynamics (FTT) . Ahmadi and colleagues optimized power and efficiency in a solar powered Stirling heat engine based on FTT and NSGAII analysis and algorithm, respectively.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis and Comparison of Performances of Air Standard Atkinson, Otto, and Diesel Cycles with Heat Transfer Considerations

Noroozian

Sadaghiani

Ahmadi

et al. 2017

Heat Trans. Asian Res.

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This paper focuses on the overall performances of Otto, Atkinson, and Diesel air standard cycles. This study compares performance of these cycles with regard to parameters such as variable specific heat ratio, heat transfer loss, frictional loss, and internal irreversibility based on finite-time thermodynamics. The relationship between thermal efficiency and compression ratio, and between power output and compression ratio of these cycles are obtained by numerical examples. In this study, it is assumed that during the combustion process, the heat transfer occurs only through the cylinder wall. The heat transfer is affected by the average temperature of both the cylinder wall and the working fluid. The results show that for each cycle, with the increase of the compression ratio in the specific mean piston speed, power output and thermal efficiency first increase and after reaching their maximum value, start to decrease. The results also indicate that maximum power output and maximum thermal efficiency of an Atkinson cycle could be higher than the values of these parameters in Diesel cycle and Otto cycle in the same operating conditions. The maximum power output and the maximum thermal efficiency of the Otto cycle have the lowest value among studied cycles. By increasing the mean piston speed, power output and thermal efficiency of Atkinson, Diesel, and Otto cycles start to decrease. The results of this study provide guidance for the performance analysis and show the improvement areas of practical Otto, Atkinson, and Diesel engines. C⃝ 2017 Wiley Periodicals, Inc. Heat Trans Asian Res, 46 (7): 996-1028, 2017; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj).

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Power optimization of an endoreversible closed intercooled regenerated Brayton-cycle coupled to variable-temperature heat-reservoirs

Cited by 26 publications

References 23 publications

Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

Multi-objective thermodynamic optimization of an irreversible regenerative Brayton cycle using evolutionary algorithm and decision making

Thermodynamic Analysis and Comparison of Performances of Air Standard Atkinson, Otto, and Diesel Cycles with Heat Transfer Considerations

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