Thermodynamic optimization of irreversible refrigerators

Grazzini, Giuseppe; Rocchetti, Andrea

doi:10.1016/j.enconman.2014.04.081

Cited by 30 publications

(10 citation statements)

References 19 publications

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“…They only showed their viewpoint in the second paragraph of the Introduction section, and there is no further explanation for their viewpoint or analysis or discussion on the entransy theory. The comments from Grazzini and Rocchetti [13] are just the repetition of the words from Grazzini et al [7] and Herwig [11], which have already been replied and discussed. In addition, the misused concepts in Açıkkalp's work [21] have also been pointed out in Ref.…”

Section: Negative Comments On the Entransy Theory And The Repliesmentioning

confidence: 93%

“…The T 2 was not determined arbitrarily as was believed by Awad [1] and Bejan [10]. The origin of entransy by the analogy and derivation from energy conservation and some advantages in heat transfer optimization [4,22] have been shown clearly even though they were denied by Awad [1,12], Grazzini et al [7,13], Lucia [8], Bejan [9,10] and Herwig [11], who do not accept the differences between entransy and entropy [22,23] and disregard the significant differences in the optimization results from the two methods. However, the different results obtained from the two methods demonstrate that they are not the same and have different objectives [20,22].…”

Section: Negative Comments On the Entransy Theory And The Repliesmentioning

confidence: 99%

“…In Ref. [13], the authors only cited the work of Grazzini et al [7] and Herwig [11], and claimed that ''entransy does not contain any new information in comparison with a classical analysis of systems using entropy''. The authors did not cite any of the papers [3,17,19,20] on the other side.…”

Section: Negative Comments On the Entransy Theory And The Repliesmentioning

confidence: 99%

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Reply to “Entransy unmasked” by Awad

Cheng

Liang

2014

Energy Conversion and Management

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Section: Negative Comments On the Entransy Theory And The Repliesmentioning

confidence: 93%

Section: Negative Comments On the Entransy Theory And The Repliesmentioning

confidence: 99%

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Reply to “Entransy unmasked” by Awad

Cheng

Liang

2014

Energy Conversion and Management

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“…By applying thermodynamic analysis to absorption chillers [6] have shown the necessity of accounting for internal dissipation, and defined the concept of Process Average Temperature (PAT). As for two thermal sources irreversible refrigerators, [7] use a general irreversible thermodynamic model to obtain an expression of the coefficient of performance accounting for the second principle in a way useful to produce maps of efficiency in terms of meaningful dimensionless parameters.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic optimization of three-thermal irreversible systems

Giannetti

Rocchetti²,

Saito³

2016

IJHT

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Multi-temperature-level systems enlarge the prospects and degrees of freedom for an effective design and an environment-friendly use of energy. Based on a general thermodynamic model of three-thermal cycles and finite thermal capacity of the heat sources, this paper aims at the analysis and the performance optimization of these systems by considering the influence of irreversibility. Suitable dimensionless parameters for an overall optimization are introduced and their influence on the cycle efficiency is investigated. This approach identifies the limitations imposed to the physical processes by accounting for the inevitable dissipation due to their constrained duration and intensity, and constitutes a general thermodynamic criterion for the optimization of three-thermal irreversible systems. Dependence on the main factors is highlighted in a way that shows how to change them in order to improve the overall efficiency. Under this point of view, the analysis evaluates COP improvements and can be used to perform plant diagnostics, besides predicting the system performance. The use of this criterion is exemplified for the absorption chiller application case.

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“…By applying thermodynamic analysis to absorption chillers [8] have shown the necessity of accounting for internal dissipation, and defined the concept of Process Average Temperature (PAT). This paper follows [9] and presents a characterization of a three thermal sources absorption heat transformer with finite thermal capacity of the heat sources that considers the influence of both heat and mass transfer irreversibility of the refrigerant and the absorptive solution on the cycle efficiency.…”

mentioning

confidence: 99%

Thermodynamic Analysis of Irreversible Heat-transformers

Giannetti¹,

Arnas²,

Rocchetti³

et al. 2015

MST

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Absorption heat transformers extend the possibilities for efficient and environment-friendly energy conversion processes. Based on a general thermodynamic model of three-thermal cycles with finite thermal capacity of the heat sources, this paper is intent upon analyzing and optimizing the performance of absorption heat transformers, by including the influence of irreversibility in the analytical expression of the system efficiency. Dimensionless parameters for an overall optimization are defined and a first screening is performed to clarify their influence. Dependence on the main factors is highlighted to suggest how to change them in order to enhance the whole system performance. Under this point of view, the analysis evaluates coefficient of performance (COP) improvements and can be used to perform existing plant diagnostics, besides predicting the system performance. The use of this criterion is exemplified for specific heat transformers data from literature. This approach identifies the limitations imposed to the physical processes by accounting for the inevitable dissipation due to their constrained duration and intensity, and constitutes a general thermodynamic criterion for the optimization of three-thermal irreversible systems. AbstrakAnalisis Termodinamika Ireversibel Heat-transformator. Penyerapan panas transformator memperluas kemungkinan adanya proses konversi energi yang efisien dan ramah lingkungan. Berdasarkan model termodinamika umum siklus three-thermal dengan kapasitas termal yang terbatas dari sumber panas, tulisan ini bertujuan untuk menganalisis dan mengoptimalkan kinerja penyerapan panas transformator, dengan memasukkan pengaruh ireversibilitas dalam ekspresi sistem analitis efisiensi. Parameter berdimensi untuk optimasi secara menyeluruh dan yang pertama dilakukan adalah penyaringan untuk memperjelas pengaruh masing-masing. Ketergantungan pada faktor utama menyoroti dan menunjukkan bagaimana mengubah mereka untuk meningkatkan kinerja sistem secara keseluruhan. Melalui sudut pandang ini, analisis evaluasi perbaikan COP dapat digunakan untuk melakukan diagnosis tanaman yang ada, selain memprediksi kinerja sistem secara keseluruhan. Pendekatan ini mengidentifikasi keterbatasan dalam proses fisik, yang berkontribusi untuk pembuangan tidak terelakkan terkendala lamanya penyinaran dan intensitas, merupakan sebuah kriteria termodinamika umum untuk optimalisasi sistem three-thermal ireversibel.

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Thermodynamic optimization of irreversible refrigerators

Cited by 30 publications

References 19 publications

Reply to “Entransy unmasked” by Awad

Reply to “Entransy unmasked” by Awad

Thermodynamic optimization of three-thermal irreversible systems

Thermodynamic Analysis of Irreversible Heat-transformers

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