A class of irreversible Carnot refrigeration cycles with a general heat transfer law

Yan, Zijun; Chen, Jincan

doi:10.1088/0022-3727/23/2/002

Cited by 176 publications

(144 citation statements)

References 11 publications

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“…(3.12) and the picture in Fig. 1(b), the entropy change per unit time of the extended system can be expressed in canonical form (11) provided that we use the corresponding relations d [49]. Assume that N electrons flow through the generator during time interval τ .…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…The other classic topic on nonequilibrium processes is finite-time thermodynamics [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] which is concerned * Corresponding author. Email: tuzc@bnu.edu.cn mainly with the energy conversion efficiency for heat devices including heat engines and refrigerators that complete thermodynamic cycles in finite time or operate in finite net rate.…”

Section: Introductionmentioning

confidence: 99%

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Weighted reciprocal of temperature, weighted thermal flux, and their applications in finite-time thermodynamics

Sheng

2014

Phys. Rev. E

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The concepts of weighted reciprocal of temperature and weighted thermal flux are proposed for a heat engine operating between two heat baths and outputting mechanical work. With the aid of these two concepts, the generalized thermodynamic fluxes and forces can be expressed in a consistent way within the framework of irreversible thermodynamics. Then the efficiency at maximum power output for a heat engine, one of key topics in finite-time thermodynamics, is investigated on the basis of a generic model under the tight-coupling condition. The corresponding results have the same forms as those of low-dissipation heat engines [M. Esposito, R. Kawai, K. Lindenberg, and C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The mappings from two kinds of typical heat engines, such as the low-dissipation heat engine and the Feynman ratchet, into the present generic model are constructed. The universal efficiency at maximum power output up to the quadratic order is found to be valid for a heat engine coupled symmetrically and tightly with two baths. The concepts of weighted reciprocal of temperature and weighted thermal flux are also transplanted to the optimization of refrigerators.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Weighted reciprocal of temperature, weighted thermal flux, and their applications in finite-time thermodynamics

Sheng

2014

Phys. Rev. E

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“…To transfer heat from the cold bath to the hot bath, work has to be done on the system and hence, we have W = Q h + Q c < 0. The coefficient of performance (COP) is defined as ζ = Q c /|W| [50,51].…”

Section: Performance As a Refrigeratormentioning

confidence: 99%

Implications of Coupling in Quantum Thermodynamic Machines

Thomas

Banik

Ghosh

2017

Entropy

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Abstract:We study coupled quantum systems as the working media of thermodynamic machines. Under a suitable phase-space transformation, the coupled systems can be expressed as a composition of independent subsystems. We find that for the coupled systems, the figures of merit, that is the efficiency for engine and the coefficient of performance for refrigerator, are bounded (both from above and from below) by the corresponding figures of merit of the independent subsystems. We also show that the optimum work extractable from a coupled system is upper bounded by the optimum work obtained from the uncoupled system, thereby showing that the quantum correlations do not help in optimal work extraction. Further, we study two explicit examples; coupled spin-1/2 systems and coupled quantum oscillators with analogous interactions. Interestingly, for particular kind of interactions, the efficiency of the coupled oscillators outperforms that of the coupled spin-1/2 systems when they work as heat engines. However, for the same interaction, the coefficient of performance behaves in a reverse manner, while the systems work as the refrigerator. Thus, the same coupling can cause opposite effects in the figures of merit of heat engine and refrigerator.

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“…(11), (12), (13), and (14), together with use of Eqs. (15), (16), and (17), we can derive after some simple reshuffling,…”

Section: Optimum Analysismentioning

confidence: 99%

“…Various optimization criteria [16][17][18][19][20][21][22] have been proposed in optimum analysis of a classical or quantum refrigeration cycle. Chen and Yan [16] introduced the function χ = εQ c /τ , with Q c the heat transported from the cold reservoir and τ the cycle time, as a target function within finite-time-thermodynamics context. Velasco et al [17] adopted the per-unit-time COP as a target function while Allahverdyan et al [18] introduced εQ c to be the target function.…”

Section: Introductionmentioning

confidence: 99%

Coefficient of performance for a low-dissipation Carnot-like refrigerator with nonadiabatic dissipation

et al. 2013

Phys. Rev. E

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We study the coefficient of performance (COP) and its bounds of the Canot-like refrigerator working between two heat reservoirs at constant temperatures T h and T c , under two optimization criteria χ and Ω. In view of the fact that an "adiabatic" process takes finite time and is nonisentropic, the nonadiabatic dissipation and the finite time required for the "adiabatic" processes are taken into account. For given optimization criteria, we find that the lower and upper bounds of the COP are the same as the corresponding ones obtained from the previous idealized models where any adiabatic process undergoes instantaneously with constant entropy. When the dissipations of two "isothermal" and two "adiabatic" processes are symmetric, respectively, our theoretical predictions match the observed COP's of real refrigerators more closely than the ones derived in the previous models, providing a strong argument in favor of our approach.

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A class of irreversible Carnot refrigeration cycles with a general heat transfer law

Cited by 176 publications

References 11 publications

Weighted reciprocal of temperature, weighted thermal flux, and their applications in finite-time thermodynamics

Weighted reciprocal of temperature, weighted thermal flux, and their applications in finite-time thermodynamics

Implications of Coupling in Quantum Thermodynamic Machines

Coefficient of performance for a low-dissipation Carnot-like refrigerator with nonadiabatic dissipation

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