A model for study and optimization of real-operating refrigeration machines

Petre, Camelia; Feidt, Michel; Costea, Monica; Petrescu, Stoian

doi:10.1002/er.1433

Cited by 17 publications

(12 citation statements)

References 5 publications

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“…Hereinafter, it is chosen to work with the ratio I H , that can be either a parameter (constant on a certain domain), or a function to be identified [18], or sought using the Direct Method, for example, by assuming degradation mechanisms [15].…”

Section: Optimization General Approachmentioning

confidence: 99%

Nonlinear Thermodynamic Analysis and Optimization of a Carnot Engine Cycle

Feidt

Costea

Petrescu

et al. 2016

Entropy

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Abstract:As part of the efforts to unify the various branches of Irreversible Thermodynamics, the proposed work reconsiders the approach of the Carnot engine taking into account the finite physical dimensions (heat transfer conductances) and the finite speed of the piston. The models introduce the irreversibility of the engine by two methods involving different constraints. The first method introduces the irreversibility by a so-called irreversibility ratio in the entropy balance applied to the cycle, while in the second method it is emphasized by the entropy generation rate. Various forms of heat transfer laws are analyzed, but most of the results are given for the case of the linear law. Also, individual cases are studied and reported in order to provide a simple analytical form of the results. The engine model developed allowed a formal optimization using the calculus of variations.

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Section: Optimization General Approachmentioning

confidence: 99%

Nonlinear Thermodynamic Analysis and Optimization of a Carnot Engine Cycle

Feidt

Costea

Petrescu

et al. 2016

Entropy

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“…The usefulness of thermodynamics to develop more significant upper bounds for various optimization criteria concerning reverse cycle machines and their possible interrelation was reviewed in [6]. The importance of irreversibility in the characterization of reverse cycle machines was also highlighted.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of the Irreversibilities in Solar Absorption Refrigerators

Berrich

Fellah

Brahim

et al. 2016

Entropy

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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/Q e are studied. This may help a constructor to well dimension the solar machine under an optimal technico-economical criterion A/Q e and with reasonable irreversibility on the refrigerator. The solar concentrator temperature effect on the total exchanged area, on the technico-economical ratio A/Q e , 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.

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“…Several models have been developed for direct and reverse cycle thermal machines as Stirling, Carnot, Otto, Diesel, Ericsson, Brayton-Joule, etc. [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Unification perspective of finite physical dimensions thermodynamics and finite speed thermodynamics

Petrescu

Feidt

Enache

et al. 2015

Int J Energy Environ Eng

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The paper studies the possibility of unifying the two branches of the irreversible engineering thermodynamics, namely finite physical dimensions thermodynamics (FPDT) and finite speed thermodynamics (FST), aiming to take into account their benefits and successes and to eliminate as much as possible their disadvantages. Actually, the two branches have the same goal, that of optimizing the performance of thermal machines and they were developed almost in parallel. Analysis of thermal machines cycles using the FPDT is based on the first and second law of thermodynamics, in the presence of the external irreversibility generated by the heat transfer at finite temperature difference at the thermal reservoirs and internal irreversibility, using the internal source of entropy considered as parameter or function to be specified. The FST is based on the mathematical expression of the first law for process with finite speed that involves three causes of internal irreversibility, namely the finite speed of the piston, internal friction and throttling. The direct method is used in the analysis of thermal machines cycles to provide analytical expression of the machine performance (efficiency and power) as a function of the speed of the process. The significant progress of these two branches of irreversible engineering thermodynamics makes their unification a desirable outcome. We hope that the new model yielded from this study will provide an even more important tool for engineers that will help their attempt to a better design and optimization of thermal machines.

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A model for study and optimization of real-operating refrigeration machines

Cited by 17 publications

References 5 publications

Nonlinear Thermodynamic Analysis and Optimization of a Carnot Engine Cycle

Nonlinear Thermodynamic Analysis and Optimization of a Carnot Engine Cycle

Thermodynamic Analysis of the Irreversibilities in Solar Absorption Refrigerators

Unification perspective of finite physical dimensions thermodynamics and finite speed thermodynamics

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