Energetic Optimization Considering a Generalization of the Ecological Criterion in Traditional Simple-Cycle and Combined-Cycle Power Plants

AbstractThe fundamental issue in the energetic performance of power plants, working both as traditional fuel engines and as combined-cycle turbines (gas-steam), lies in quantifying the internal irreversibilities which are associated with the working substance operating in cycles. The purpose of several irreversible energy converter models is to find objective thermodynamic functions that determine operation modes for real thermal engines and at the same time study the trade-off between energy losses per cycle and the useful energy. As those objective functions, we focus our attention on a generalization of the so-called ecological function in terms of an ϵ parameter that depends on the particular heat transfer law used in the irreversible heat engine model. In this work, we mathematically describe the configuration space of an irreversible Curzon–Ahlborn type model. The above allows to determine the optimal relations between the model parameters so that a power plant operates in physically accessible regions, taking into account internal irreversibilities, introduced in two different ways (additively and multiplicatively). In addition, we establish the conditions that the ϵ parameter must fulfill for the energy converter to work in an optimal region between maximum power output and maximum efficiency points.

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The Role of Internal Irreversibilities in the Performance and Stability of Power Plant Models Working at Maximum ϵ-Ecological Function

Journal of Non-Equilibrium Thermodynamics ◽

10.1515/jnet-2021-0030 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Gabriel Valencia-Ortega ◽

Sergio Levario-Medina ◽

Marco Antonio Barranco-Jiménez

Keyword(s):

Power Plants ◽

Heat Engine ◽

Combined Cycle ◽

Ecological Function ◽

Operating Conditions ◽

Maximum Efficiency ◽

Working Fluid ◽

Engine Model ◽

Improved Stability ◽

The Stability

Abstract The proposal of models that account for the irreversibilities within the core engine has been the topic of interest to quantify the useful energy available during its conversion. In this work, we analyze the energetic optimization and stability (local and global) of three power plants, nuclear, combined-cycle, and simple-cycle ones, by means of the Curzon–Ahlborn heat engine model which considers a linear heat transfer law. The internal irreversibilities of the working fluid measured through the r-parameter are associated with the so-called “uncompensated Clausius heat.” In addition, the generalization of the ecological function is used to find operating conditions in three different zones, which allows to carry out a numerical analysis focused on the stability of power plants in each operation zone. We noted that not all power plants reveal stability in all the operation zones when irreversibilities are considered through the r-parameter on real-world power plants. However, an improved stability is shown in the zone limited by the maximum power output and maximum efficiency regimes.

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Thermodynamic Analysis of Different Configurations of Combined Cycle Power Plants

Mechanical Engineering Research ◽

10.5539/mer.v5n2p89 ◽

2015 ◽

Vol 5 (2) ◽

pp. 89

Author(s):

Munzer S. Y. Ebaid ◽

Qusai Z. Al-hamdan

Keyword(s):

Gas Turbine ◽

Power Plants ◽

Combined Cycle ◽

Cycle Performance ◽

Maximum Efficiency ◽

Specific Work ◽

Slight Effect ◽

Turbine Engine ◽

Gas Turbine Cycle ◽

Cycle Efficiency

<p class="1Body">Several modifications have been made to the simple gas turbine cycle in order to increase its thermal efficiency but within the thermal and mechanical stress constrain, the efficiency still ranges between 38 and 42%. The concept of using combined cycle power or CPP plant would be more attractive in hot countries than the combined heat and power or CHP plant. The current work deals with the performance of different configurations of the gas turbine engine operating as a part of the combined cycle power plant. The results showed that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance.</p>

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Hybrid Heat Engines: The Power Generation Systems of the Future

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/2000-gt-0549 ◽

2000 ◽

Cited By ~ 4

Author(s):

Abbie Layne ◽

Scott Samuelsen ◽

Mark Williams ◽

Patricia Hoffman

Keyword(s):

Fuel Cell ◽

Gas Turbine ◽

Power Plants ◽

Technology Development ◽

Heat Engine ◽

Combined Cycle ◽

Heat Engines ◽

Hybrid Concept ◽

Hybrid Program ◽

Power Generation Systems

A hybrid heat engine results from the fusion of a heat engine with a non-heat-engine based cycle (unlike systems). The term combined cycle, which refers to similar arrangements, is reserved for the combination of two or more heat engines (like systems). The resulting product of the integration of a gas turbine and a fuel cell is referred to here as a hybrid heat engine or “Hybrid” for short. The intent of this paper is to provide, to the gas turbine community, a review of the present status of hybrid heat engine technologies. Current and projected activities associated with this emerging concept are also presented. The National Energy Technology Laboratory (NETL) is collaborating with other sponsors and the private sector to develop a Hybrid Program. This program will address the issues of technology development, integration, and ultimately the demonstration of what may be the most efficient of power plants in the world — the Hybrid System. Analyses of several Hybrid concepts have indicated the potential of ultra-high efficiencies (approaching 80%). In the Hybrid, the synergism between the gas turbine and fuel cell provides higher efficiencies and lower costs than either system can alone. Testing of the first Hybrid concept has been initiated at the National Fuel Cell Research Center (NFCRC).

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Analysis on the Performance of a Thermoelectric Generator

Journal of Energy Resources Technology ◽

10.1115/1.483163 ◽

1999 ◽

Vol 122 (2) ◽

pp. 61-63 ◽

Cited By ~ 37

Author(s):

Jincan Chen ◽

Chih Wu

Keyword(s):

Power Output ◽

Physical Meaning ◽

Design Parameter ◽

Thermoelectric Generator ◽

Heat Engine ◽

Simple Expression ◽

Maximum Efficiency ◽

Thermoelectric Generators ◽

Optimal Range ◽

Engine Model

An externally and internally irreversible heat engine model of thermoelectric generators is used to analyze the so-called device-design parameter introduced by O¨zkaynak et al. The simple expression of the parameter is given and its physical meaning is expounded. Moreover, the optimal range of the parameter is determined and the problems relative to the maximum power output and maximum efficiency are discussed. Some meaningful results are obtained. [S0195-0738(00)00401-5]

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Hybrid Fuel Cell Heat Engines: Recent Efforts

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/2001-gt-0588 ◽

2001 ◽

Cited By ~ 5

Author(s):

Abbie Layne ◽

Scott Samuelsen ◽

Mark Williams ◽

Norman Holcombe

Keyword(s):

Fuel Cell ◽

Gas Turbine ◽

Power Plants ◽

State Energy ◽

Technology Development ◽

Heat Engine ◽

Combined Cycle ◽

Heat Engines ◽

Hybrid Concept ◽

Hybrid Program

A hybrid heat engine results from the fusion of a heat engine with a non-heat-engine based cycle (unlike systems). The term combined cycle, which refers to similar arrangements, is reserved for the combination of two or more heat engines (like systems). The resulting product of the integration of a gas turbine and a fuel cell is referred to here as a hybrid heat engine or “Hybrid” for short. The intent of this paper is to provide, to the gas turbine community, a review of the present status of hybrid heat engine technologies. Current and projected activities associated with this emerging concept are also presented. The National Energy Technology Laboratory (NETL) is collaborating with other sponsors and the private sector to develop a Hybrid Program. This program will address the issues of technology development, integration, and ultimately the demonstration of what may be the most efficient of power plants in the world—the Hybrid System. In the Hybrid, the synergism between the gas turbine and fuel cell provides higher efficiencies and lower costs than either system can alone. Testing of the first hybrid concept has been initiated at the National Fuel Cell Research Center (NFCRC). FuelCell Energy (FCE) will be testing its first hybrid in 2002. Honeywell’s hybrid program has just begun under the Solid State Energy Conversion Alliance (SECA). SECA fuel cells will ultimately be hybridized with turbines. A competitive SECA solicitation is planned for conceptual studies in 2003. Industry teams will be selected in 2004 to further develop hybrid fuel cell systems.

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Application of RQL Coal Combustor Technology to Large Utility Gas Turbines

Volume 3C: General ◽

10.1115/93-gt-360 ◽

1993 ◽

Author(s):

C. Wilkes ◽

R. A. Wenglarz ◽

P. J. Hart ◽

H. C. Mongia

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Power Plants ◽

Heat Engine ◽

Combined Cycle ◽

Pulverized Coal ◽

Department Of Energy ◽

Cycle Performance ◽

Proof Of Concept ◽

Combustion System

This paper describes the application of Allison’s rich-quench-lean (RQL) coal combustor technology to large utility gas turbines in the 100 MWe+ class. The RQL coal combustor technology was first applied to coal derived fuels in the 1970s and has been under development since 1986 as part of a Department of Energy (DOE)-sponsored heat engine program aimed at proof of concept testing of coal-fired gas turbine technology. The 5 MWe proof of concept engine/coal combustion system was first tested on coal water slurry (CWS); it is now being prepared for testing on dry pulverized coal. A design concept to adapt the RQL coal combustor technology developed under the DOE program to large utility-sized gas turbines has been proposed for a Clean Coal V program. The engine and combustion system modifications required for application to coal-fueled combined cycle power plants using 100 MWe+ gas turbines are described. Estimates for emissions and cycle performance are given. Included are comparisons with a conventional pulverized coal plant that illustrates the advantages of incorporating a gas turbine on cycle efficiency and emission rate.

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Structural Material Trends in Future Power Plants

Journal of Engineering Materials and Technology ◽

10.1115/1.482795 ◽

2000 ◽

Vol 122 (3) ◽

pp. 256-258 ◽

Cited By ~ 1

Author(s):

Horst Hack

Keyword(s):

High Temperature ◽

High Performance ◽

Power Plants ◽

Ceramic Matrix Composites ◽

Ceramic Composites ◽

Strength Properties ◽

Combined Cycle ◽

Maximum Efficiency ◽

High Temperature Strength ◽

Matrix Composites

Environmental and economic concerns necessitate advances in power generation technology. Future power plants will be more fuel efficient, environmentally benign, and economical than current power plants. A high performance power system (HIPPS), based on a coal-fired combined cycle, is currently being developed. The corrosion and temperature-strength properties of currently available metallic materials limit the maximum efficiency of this cycle. Recently, ceramic matrix composites have shown promise in overcoming the design limitations on future power plants. In particular, the high-temperature strength, and corrosion and erosion resistant properties of continuous fiber ceramic composites (CFCCs) will allow engineers to design high-temperature heat exchangers, cyclone vortex finder tubes, and other components. Research is being performed to evaluate candidate materials for use in future power plants. [S0094-4289(00)00203-6]

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