Special Issue "Entropy Generation in Thermal Systems and Processes 2015"

A special issue of Entropy (ISSN 1099-4300).

Deadline for manuscript submissions: closed (30 September 2015).

Special Issue Editors

Prof. Dr. Morin Celine

Guest Editor
LAMIH CNRS UMR 8201, Université de Valenciennes et du Hainaut-Cambrésis, Campus Mont Houy, 59313 Valenciennes Cedex 9 France
Interests: multi-physics and multi-scale analysis of energy production systems; modeling of energy conversion machines, in steady and transient regimes: global analysis of the machine and its components; thermodynamics optimization ; energy and exergy analysis
Prof. Dr. Bernard Desmet

Guest Editor
University of Valenciennes et du Hainaut-Cambrésis, Campus Mont Houy, 59313 Valenciennes Cedex 9 France
Interests: multi-physics and multi-scale analysis of energy production systems; modeling of energy conversion machines, thermodynamics optimization; energy and exergy analysis
Prof. Dr. Fethi Aloui

Guest Editor
LAMIH CNRS UMR 8201, Université de Valenciennes et du Hainaut-Cambrésis, Campus Mont Houy, 59313 Valenciennes Cedex 9 France
Interests: Fluid Mechanics; Heat and mass transfer; Multi-physics and multi-scale analysis of energy production systems; modeling of energy conversion machines, in steady and transient regimes: global analysis of the machine and its components; thermodynamics optimization ; energy and exergy analysis

Special Issue Information

Dear Colleagues,

Please visit this site http://www.univ-valenciennes.fr/evenements/ieees7/topics for a detailed description of this special issue. The Special Issue’s will mainly consist of selected papers presented at "7th International Exergy, Energy and Environment Symposium". Papers in the following topic are also welcomed on this special issue:

  • Thermodynamics Optimization
  • Entropy & Exergy Analyses
  • Entropy Generation Minimization

Prof. Dr. Bernard Desmet
Dr. Morin Celine
Prof. Dr. Fethi Aloui
Guest Editors

Relevant Special issue: https://www.mdpi.com/journal/entropy/special_issues/thermal_systems_processes

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Entropy is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (11 papers)

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Research

Open AccessArticle
Analyses of the Instabilities in the Discretized Diffusion Equations via Information Theory
Entropy 2016, 18(4), 155; https://doi.org/10.3390/e18040155 - 21 Apr 2016
Abstract
In a previous investigation (Bigerelle and Iost, 2004), the authors have proposed a physical interpretation of the instability λ = Δtx2 > 1/2 of the parabolic partial differential equations when solved by finite differences. However, our results were obtained [...] Read more.
In a previous investigation (Bigerelle and Iost, 2004), the authors have proposed a physical interpretation of the instability λ = Δtx2 > 1/2 of the parabolic partial differential equations when solved by finite differences. However, our results were obtained using integration techniques based on erf functions meaning that no statistical fluctuation was introduced in the mathematical background. In this paper, we showed that the diffusive system can be divided into sub-systems onto which a Brownian motion is applied. Monte Carlo simulations are carried out to reproduce the macroscopic diffusive system. It is shown that the amount of information characterized by the compression ratio of information of the system is pertinent to quantify the entropy of the system according to some concepts introduced by the authors (Bigerelle and Iost, 2007). Thanks to this mesoscopic discretization, it is proved that information on each sub-cell of the diffusion map decreases with time before the unstable equality λ = 1/2 and increases after this threshold involving an increase in negentropy, i.e., a decrease in entropy contrarily to the second principle of thermodynamics. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Energetic and Exergetic Analysis of a Heat Exchanger Integrated in a Solid Biomass-Fuelled Micro-CHP System with an Ericsson Engine
Entropy 2016, 18(4), 154; https://doi.org/10.3390/e18040154 - 20 Apr 2016
Cited by 2
Abstract
A specific heat exchanger has been developed to transfer heat from flue gas to the working fluid (hot air) of the Ericsson engine of a solid biomass-fuelled micro combined heat and power (CHP). In this paper, the theoretical and experimental energetic analyses of [...] Read more.
A specific heat exchanger has been developed to transfer heat from flue gas to the working fluid (hot air) of the Ericsson engine of a solid biomass-fuelled micro combined heat and power (CHP). In this paper, the theoretical and experimental energetic analyses of this heat exchanger are compared. The experimental performances are described considering energetic and exergetic parameters, in particular the effectiveness on both hot and cold sides. A new exergetic parameter called the exergetic effectiveness is introduced, which allows a comparison between the real and the ideal heat exchanger considering the Second Law of Thermodynamics. A global analysis of exergetic fluxes in the whole micro-CHP system is presented, showing the repartition of the exergy destruction among the components. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Exergy Analysis of Complex Ship Energy Systems
Entropy 2016, 18(4), 127; https://doi.org/10.3390/e18040127 - 08 Apr 2016
Cited by 5
Abstract
With multiple primary and secondary energy converters (diesel engines, steam turbines, waste heat recovery (WHR) and oil-fired boilers, etc.) and extensive energy networks (steam, cooling water, exhaust gases, etc.), ships may be considered as complex energy systems. Understanding and optimizing such [...] Read more.
With multiple primary and secondary energy converters (diesel engines, steam turbines, waste heat recovery (WHR) and oil-fired boilers, etc.) and extensive energy networks (steam, cooling water, exhaust gases, etc.), ships may be considered as complex energy systems. Understanding and optimizing such systems requires advanced holistic energy modeling. This modeling can be done in two ways: The simpler approach focuses on energy flows, and has already been tested, approved and presented; a new, more complicated approach, focusing on energy quality, i.e., exergy, is presented in this paper. Exergy analysis has rarely been applied to ships, and, as a general rule, the shipping industry is not familiar with this tool. This paper tries to fill this gap. We start by giving a short reminder of what exergy is and describe the principles of exergy modeling to explain what kind of results should be expected from such an analysis. We then apply these principles to the analysis of a large two-stroke diesel engine with its cooling and exhaust systems. Simulation results are then presented along with the exergy analysis. Finally, we propose solutions for energy and exergy saving which could be applied to marine engines and ships in general. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Thermodynamic Analysis of the Irreversibilities in Solar Absorption Refrigerators
Entropy 2016, 18(4), 107; https://doi.org/10.3390/e18040107 - 24 Mar 2016
Cited by 1
Abstract
A thermodynamic analysis of the irreversibility on solar absorption refrigerators is presented. Under the hierarchical decomposition and the hypothesis of an endoreversible model, many functional and practical domains are defined. The effect of external heat source temperature on the entropy rate and on [...] Read more.
A thermodynamic analysis of the irreversibility on solar absorption refrigerators is presented. Under the hierarchical decomposition and the hypothesis of an endoreversible model, many functional and practical domains are defined. The effect of external heat source temperature on the entropy rate and on the inverse specific cooling load (ISCL) multiplied by the total area of the refrigerator A/Qe are studied. This may help a constructor to well dimension the solar machine under an optimal technico-economical criterion A/Qe and with reasonable irreversibility on the refrigerator. The solar concentrator temperature effect on the total exchanged area, on the technico-economical ratio A/Qe, and on the internal entropy rate are illustrated and discussed. The originality of these results is that they allow a conceptual study of a solar absorption refrigeration cycle. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Hierarchical Decomposition Thermodynamic Approach for the Study of Solar Absorption Refrigerator Performance
Entropy 2016, 18(3), 82; https://doi.org/10.3390/e18030082 - 04 Mar 2016
Cited by 1
Abstract
A thermodynamic approach based on the hierarchical decomposition which is usually used in mechanical structure engineering is proposed. The methodology is applied to an absorption refrigeration cycle. Thus, a thermodynamic analysis of the performances on solar absorption refrigerators is presented. Under the hypothesis [...] Read more.
A thermodynamic approach based on the hierarchical decomposition which is usually used in mechanical structure engineering is proposed. The methodology is applied to an absorption refrigeration cycle. Thus, a thermodynamic analysis of the performances on solar absorption refrigerators is presented. Under the hypothesis of an endoreversible model, the effects of the generator, the solar concentrator and the solar converter temperatures, on the coefficient of performance (COP), are presented and discussed. In fact, the coefficient of performance variations, according to the ratio of the heat transfer areas of the high temperature part (the thermal engine 2) Ah and the heat transfer areas of the low temperature part (the thermal receptor) Ar variations, are studied in this paper. For low values of the heat-transfer areas of the high temperature part and relatively important values of heat-transfer areas of the low temperature part as for example Ah equal to 30% of Ar, the coefficient of performance is relatively important (approximately equal to 65%). For an equal-area distribution corresponding to an area ratio Ah/Ar of 50%, the COP is approximately equal to 35%. The originality of this deduction is that it allows a conceptual study of the solar absorption cycle. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Fractal Representation of Exergy
Entropy 2016, 18(2), 56; https://doi.org/10.3390/e18020056 - 06 Feb 2016
Cited by 3
Abstract
We developed a geometrical model to represent the thermodynamic concepts of exergy and anergy. The model leads to multi-scale energy lines (correlons) that we characterised by fractal dimension and entropy analyses. A specific attention will be paid to overlapping points, rising interesting remarks [...] Read more.
We developed a geometrical model to represent the thermodynamic concepts of exergy and anergy. The model leads to multi-scale energy lines (correlons) that we characterised by fractal dimension and entropy analyses. A specific attention will be paid to overlapping points, rising interesting remarks about trans-scale dynamics of heat flows. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Preliminary Numerical Investigations of Entropy Generation in Electric Machines Based on a Canonical Configuration
Entropy 2015, 17(12), 8187-8206; https://doi.org/10.3390/e17127874 - 15 Dec 2015
Cited by 3
Abstract
The present paper analyzes numerically the entropy generation induced by forced convection in a canonical configuration. The configuration itself includes two well known fluid dynamic problems: (1) an external flow (flow around a cylinder, Kármán flow); and (2) an internal flow (flow between [...] Read more.
The present paper analyzes numerically the entropy generation induced by forced convection in a canonical configuration. The configuration itself includes two well known fluid dynamic problems: (1) an external flow (flow around a cylinder, Kármán flow); and (2) an internal flow (flow between two concentric rotating cylinders, Couette flow). In many daily engineering issues (e.g., cooling of electric machines), a combination of these problems occurs and has to be investigated. Using the canonical configuration, the fields of entropy generation are analyzed in this work for a constant wall heat flux but varying two key parameters (Reynolds numbers Re and Re0). The entropy generation due to conduction shows an absolute minimum around Re0 = 10,000. The same minima can be found by a detailed analysis of the temperature profile. Thus, entropy generation seems to be a suitable indicator for optimizing heat exchange processes and delivers a large amount of information concerning fluid and heat transport. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Comparison Based on Exergetic Analyses of Two Hot Air Engines: A Gamma Type Stirling Engine and an Open Joule Cycle Ericsson Engine
Entropy 2015, 17(11), 7331-7348; https://doi.org/10.3390/e17117331 - 28 Oct 2015
Cited by 4
Abstract
In this paper, a comparison of exergetic models between two hot air engines (a Gamma type Stirling prototype having a maximum output mechanical power of 500 W and an Ericsson hot air engine with a maximum power of 300 W) is made. Referring [...] Read more.
In this paper, a comparison of exergetic models between two hot air engines (a Gamma type Stirling prototype having a maximum output mechanical power of 500 W and an Ericsson hot air engine with a maximum power of 300 W) is made. Referring to previous energetic analyses, exergetic models are set up in order to quantify the exergy destruction and efficiencies in each type of engine. The repartition of the exergy fluxes in each part of the two engines are determined and represented in Sankey diagrams, using dimensionless exergy fluxes. The results show a similar proportion in both engines of destroyed exergy compared to the exergy flux from the hot source. The compression cylinders generate the highest exergy destruction, whereas the expansion cylinders generate the lowest one. The regenerator of the Stirling engine increases the exergy resource at the inlet of the expansion cylinder, which might be also set up in the Ericsson engine, using a preheater between the exhaust air and the compressed air transferred to the hot heat exchanger. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
A Thermodynamic Entropy Approach to Reliability Assessment with Applications to Corrosion Fatigue
Entropy 2015, 17(10), 6995-7020; https://doi.org/10.3390/e17106995 - 16 Oct 2015
Cited by 22
Abstract
This paper outlines a science-based explanation of damage and reliability of critical components and structures within the second law of thermodynamics. The approach relies on the fundamentals of irreversible thermodynamics, specifically the concept of entropy generation as an index of degradation and damage [...] Read more.
This paper outlines a science-based explanation of damage and reliability of critical components and structures within the second law of thermodynamics. The approach relies on the fundamentals of irreversible thermodynamics, specifically the concept of entropy generation as an index of degradation and damage in materials. All damage mechanisms share a common feature, namely energy dissipation. Dissipation, a fundamental measure for irreversibility in a thermodynamic treatment of non-equilibrium processes, is quantified by entropy generation. An entropic-based damage approach to reliability and integrity characterization is presented and supported by experimental validation. Using this theorem, which relates entropy generation to dissipative phenomena, the corrosion fatigue entropy generation function is derived, evaluated, and employed for structural integrity and reliability assessment of aluminum 7075-T651 specimens. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Entropy Generation through Deterministic Spiral Structures in a Corner Boundary-Layer Flow
Entropy 2015, 17(8), 5304-5332; https://doi.org/10.3390/e17085304 - 27 Jul 2015
Cited by 1
Abstract
It is shown that nonlinear interactions between boundary layers on adjacent corner surfaces produce deterministic stream wise spiral structures. The synchronization properties of nonlinear spectral velocity equations of Lorenz form yield clearly defined deterministic spiral structures at several downstream stations. The computational procedure [...] Read more.
It is shown that nonlinear interactions between boundary layers on adjacent corner surfaces produce deterministic stream wise spiral structures. The synchronization properties of nonlinear spectral velocity equations of Lorenz form yield clearly defined deterministic spiral structures at several downstream stations. The computational procedure includes Burg’s method to obtain power spectral densities, yielding the available kinetic energy dissipation rates within the spiral structures. The singular value decomposition method is applied to the nonlinear time series solutions yielding empirical entropies, from which empirical entropic indices are then extracted. The intermittency exponents obtained from the entropic indices allow the computation of the entropy generation through the spiral structures to the final dissipation of the fluctuating kinetic energy into background thermal energy, resulting in an increase in the entropy. The entropy generation rates through the spiral structures are compared with the entropy generation rates within an empirical turbulent boundary layer at several stream wise stations. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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Open AccessArticle
Modeling and Analysis of Entropy Generation in Light Heating of Nanoscaled Silicon and Germanium Thin Films
Entropy 2015, 17(7), 4786-4808; https://doi.org/10.3390/e17074786 - 09 Jul 2015
Abstract
In this work, the irreversible processes in light heating of Silicon (Si) and Germanium (Ge) thin films are examined. Each film is exposed to light irradiation with radiative and convective boundary conditions. Heat, electron and hole transport and generation-recombination processes of electron-hole pairs [...] Read more.
In this work, the irreversible processes in light heating of Silicon (Si) and Germanium (Ge) thin films are examined. Each film is exposed to light irradiation with radiative and convective boundary conditions. Heat, electron and hole transport and generation-recombination processes of electron-hole pairs are studied in terms of a phenomenological model obtained from basic principles of irreversible thermodynamics. We present an analysis of the contributions to the entropy production in the stationary state due to the dissipative effects associated with electron and hole transport, generation-recombination of electron-hole pairs as well as heat transport. The most significant contribution to the entropy production comes from the interaction of light with the medium in both Si and Ge. This interaction includes two processes, namely, the generation of electron-hole pairs and the transferring of energy from the absorbed light to the lattice. In Si the following contribution in magnitude comes from the heat transport. In Ge all the remaining contributions to entropy production have nearly the same order of magnitude. The results are compared and explained addressing the differences in the magnitude of the thermodynamic forces, Onsager’s coefficients and transport properties of Si and Ge. Full article
(This article belongs to the Special Issue Entropy Generation in Thermal Systems and Processes 2015)
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