Proof of the Energetic Efficiency of Fresh Air, Solar Draught Power Plants

Abstract The expansion of renewable energy generation must go hand in hand with measures for reliable energy supply and energy storage. A combination of hydrogen and oxygen as storing media provided from electrolysis at high pressure and zero emission power plants is a very promising option. The Graz cycle is an oxy-fuel combined power cycle that can operate with internal H2/O2 combustion and steam as working fluid. It offers thermal efficiencies up to 68.5% (LHV). This work applies a second law analysis to the Graz cycle and determines its exergetic efficiency. Exergy destruction is broken down to the cycle’s components thus providing insights on the location and magnitude of the cycle’s inefficiencies. A sensitivity analysis identifies the cycle’s exergetic and energetic efficiency as a function of representative parameters, offering an approach for future improvements. The combination of the cycle with an electrolysis plant is subsequently analyzed as an electric energy storage system. The round trip efficiency of the storage and back conversion system is computed by taking into account the additional compression of the reactants. As part of this analysis, the effect of the electrolyzer’s operational pressure is studied by comparing several commercial electrolyzers.

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Comparative Energetic and Exergetic Analysis of Conventional and Sloped Solar Chimney Power Plants

International Journal of Energy Optimization and Engineering ◽

10.4018/ijeoe.2020100104 ◽

2020 ◽

Vol 9 (4) ◽

pp. 57-73

Author(s):

Hela Atia ◽

Adrian Ilinca ◽

Ali Snoussi ◽

Rachid Boukchina ◽

Ammar Ben Brahim

Keyword(s):

Inclination Angle ◽

Power Plants ◽

Energetic Efficiency ◽

Cfd Analysis ◽

Exergy Destruction ◽

Solar Chimney ◽

Ansys Fluent ◽

Solar Radiation Intensity ◽

Fluent Software ◽

Exergetic Analysis

A CFD analysis using ANSYS Fluent software was conducted to study the effects of collector slope on solar chimney's performances. Three solar chimney configurations, named A, B, and C, which correspond, respectively, to an inclination angle of the collector roof of 0°, 2.5°, and 5°, were investigated. The results show that the thermodynamic performances of the solar chimney were improved by increasing the inclination angle of the collector roof. In fact, the power extracted from the sloped solar chimney power plants increases with increasing the inclination angle and the solar radiation intensity, while it achieves a maximum at 800 W/m2 for configuration A. The energetic and the exergetic analysis show that configure B has the best performance in terms of conventional, effective, and total efficiencies of the collector and in terms of exergy destruction ratios in both the collector and the transition section. Whereas, configuration C has the highest amount of power extracted and the best overall energetic efficiency.

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Second Law Analysis of an Energy Storage System Consisting of an Electrolysis Plant and the Graz Cycle With Internal H2/O2 Combustion

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4044451 ◽

2019 ◽

Vol 141 (11) ◽

Cited By ~ 1

Author(s):

Simeon Dybe ◽

Tom Tanneberger ◽

Panagiotis Stathopoulos

Keyword(s):

Energy Storage ◽

Power Plants ◽

Storage System ◽

Electric Energy ◽

Energy Storage System ◽

Working Fluid ◽

Energetic Efficiency ◽

Second Law ◽

Electric Energy Storage ◽

Second Law Analysis

Abstract The expansion of renewable energy generation must go hand in hand with measures for reliable energy supply and energy storage. A combination of hydrogen and oxygen as storing media provided from electrolysis at high pressure and zero emission power plants is a very promising option. The Graz cycle is an oxy-fuel combined power cycle that can operate with internal H2/O2 combustion and steam as working fluid. It offers thermal efficiencies up to 68.5% (lower heating value - LHV). This work applies a second law analysis to the Graz cycle and determines its exergetic efficiency. Exergy destruction is broken down to the cycle's components, thus providing insights on the location and magnitude of the cycle's inefficiencies. A sensitivity analysis identifies the cycle's exergetic and energetic efficiency as a function of representative parameters, offering an approach for future improvements. The combination of the cycle with an electrolysis plant is subsequently analyzed as an electric energy storage system. The round trip efficiency of the storage and back conversion system is computed by taking into account the additional compression of the reactants. As part of this analysis, the effect of the electrolyzer's operational pressure is studied by comparing several commercial electrolyzers.

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New Running Strategies of a STIG Power Plant for District Heating

Volume 2: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation; Environmental and Regulatory Affairs ◽

10.1115/gt2006-90538 ◽

2006 ◽

Cited By ~ 2

Author(s):

F. Caresana ◽

G. Comodi ◽

L. Pelagalli ◽

D. Salvi

Keyword(s):

Economic Performance ◽

Thermal Load ◽

Power Plants ◽

District Heating ◽

Combined Heat And Power ◽

Energy Market ◽

Energetic Efficiency ◽

City District ◽

The Impact ◽

Nearby City

We describe the running plan of a 5.5-MWe-STIG-plant. Located in a medium-sized town in the centre of Italy, the plant both produces electric power and partially satisfies the thermal load of a nearby city district. An account of the Italian energy market is provided and the impact of recent legislation on plant operation is analysed. The liberalization of the Italian energy market in 1999 has significantly affected the technical and economic scenario for both existing and future power plants. As an example, we analyse the effects of liberalization on the overall performances of the plant described herein as well as the main changes in its running-strategies. A better economic result is shown to be possible in the new scenario mainly thanks to plant flexibility when operating as CHP (Combined Heat and Power) unit. The pursuit of optimum economic performance however prevents the plant from working at its best energetic efficiency.

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Technological improvements in energetic efficiency and sustainability in existing combined-cycle gas turbine (CCGT) power plants

Applied Energy ◽

10.1016/j.apenergy.2018.03.191 ◽

2018 ◽

Vol 223 ◽

pp. 30-51 ◽

Cited By ~ 10

Author(s):

Antonio Colmenar-Santos ◽

David Gómez-Camazón ◽

Enrique Rosales-Asensio ◽

Jorge-Juan Blanes-Peiró

Keyword(s):

Gas Turbine ◽

Power Plants ◽

Combined Cycle ◽

Energetic Efficiency ◽

Technological Improvements

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A Modified SSLPS Algorithm with Logistic Pseudo-Random Sequence Generator for Improving the Performance of Neka Power Plant

International Journal of Applied Evolutionary Computation ◽

10.4018/ijaec.2015010101 ◽

2015 ◽

Vol 6 (1) ◽

pp. 1-29

Author(s):

Ahmad Mozaffari ◽

Mehdi Emami ◽

Nasser L. Azad ◽

Alireza Fathi

Keyword(s):

Mathematical Model ◽

Power Plant ◽

Power Systems ◽

Power Plants ◽

Large Scale ◽

Numerical Study ◽

Random Sequence ◽

Chaotic Map ◽

Logistic Map ◽

Energetic Efficiency

Metaheuristic techniques have successfully contributed to the development and optimization of large-scale distributed power systems. The archived literature demonstrate that the modification or tuning of the parameters of specific metaheuristics can provide powerful tools suited for optimization of power plants with different types of constraints. In spite of the high potential of metaheuristics in dealing with such systems, most of the conducted researches only address the optimization of the electrical aspects of power systems. In this research, the authors intend to attest the applicability of metaheuristics for optimizing the mechanical aspects of a real-world large-scale power plant, i.e. Neka power plant sited in Mazandaran, Iran. To do so, firstly, based on the laws of thermodynamics and the physics of the problem at hand, the authors implement a mathematical model to calculate the values of exergetic efficiency, energetic efficiency, and total cost of the Neka power plant as three main objective functions. Besides, a memetic supervised neural network and Bahadori's mathematical model are used to calculate the dynamic values of specific heat over the operating procedure of the power plant. At the second stage, a modified version of a recent spotlighted Pareto based multiobjective metaheuristic called synchronous self-learning Pareto strategy (SSLPS) is proposed. The proposed technique is based on embedding logistic chaotic map into the algorithmic architecture of SSLPS. In this context, the resulting optimizer, i.e. chaos-enhanced SSLPS (C-SSLPS), uses the response of time-discrete nonlinear logistic map to update the positions of heuristic agents over the optimization procedure. For the sake of comparison, strength Pareto evolutionary algorithm (SPEA 2), non-dominated sorting genetic algorithm (NSGA-II) and standard SSLPS are taken into account. The results of the numerical study confirm the superiority of the proposed technique as compared to the other rival optimizers. Besides, it is observed that metaheuristics can be successfully used for optimizing the mechanical/energetic parameters of Neka power plant.

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Use of fractals to describe microstructures of porous thick-film platinum electrodes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121971 ◽

1992 ◽

Vol 50 (1) ◽

pp. 314-315

Author(s):

Steven D. Toteda

Keyword(s):

Fractal Dimension ◽

Power Plants ◽

Electrical Response ◽

Cubic Phase ◽

Platinum Electrodes ◽

Fine Grained ◽

Impedance Response ◽

Platinum Particles ◽

Energy Surfaces ◽

Highly Porous

Zirconia oxygen sensors, in such applications as power plants and automobiles, generally utilize platinum electrodes for the catalytic reaction of dissociating O2 at the surface. The microstructure of the platinum electrode defines the resulting electrical response. The electrode must be porous enough to allow the oxygen to reach the zirconia surface while still remaining electrically continuous. At low sintering temperatures, the platinum is highly porous and fine grained. The platinum particles sinter together as the firing temperatures are increased. As the sintering temperatures are raised even further, the surface of the platinum begins to facet with lower energy surfaces. These microstructural changes can be seen in Figures 1 and 2, but the goal of the work is to characterize the microstructure by its fractal dimension and then relate the fractal dimension to the electrical response. The sensors were fabricated from zirconia powder stabilized in the cubic phase with 8 mol% percent yttria. Each substrate was sintered for 14 hours at 1200°C. The resulting zirconia pellets, 13mm in diameter and 2mm in thickness, were roughly 97 to 98 percent of theoretical density. The Engelhard #6082 platinum paste was applied to the zirconia disks after they were mechanically polished ( diamond). The electrodes were then sintered at temperatures ranging from 600°C to 1000°C. Each sensor was tested to determine the impedance response from 1Hz to 5,000Hz. These frequencies correspond to the electrode at the test temperature of 600°C.

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The Effects of Ion Implantation on the Surface Features of Inconel 600

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118333 ◽

1985 ◽

Vol 43 ◽

pp. 288-289

Author(s):

John D. Rubio

Keyword(s):

Grain Boundary ◽

Ion Implantation ◽

Nuclear Power ◽

Power Plants ◽

Surface Region ◽

Selective Dissolution ◽

Boundary Region ◽

Near Surface ◽

Inconel 600 ◽

Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

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