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Open AccessArticle

Thermodynamic Analysis of Closed Steady or Cyclic Systems

School of Mechanical and Design Engineering, Dublin Institute of Technology, Bolton Street, Dublin 1, D01 K822, Ireland
Academic Editor: Michel Feidt
Entropy 2015, 17(10), 6712-6742; https://doi.org/10.3390/e17106712
Received: 16 July 2015 / Revised: 6 September 2015 / Accepted: 16 September 2015 / Published: 29 September 2015
(This article belongs to the Special Issue Selected Papers from 13th Joint European Thermodynamics Conference)
Closed, steady or cyclic thermodynamic systems, which have temperature variations over their boundaries, can represent an extremely large range of plants, devices or natural objects, such as combined heating, cooling and power plants, computers and data centres, and planets. Energy transfer rates can occur across the boundary, which are characterized as heat or work. We focus on the finite time thermodynamics aspects, on energy-based performance parameters, on rational efficiency and on the environmental reference temperature. To do this, we examine the net work rate of a closed, steady or cyclic system bounded by thermal resistances linked to isothermal reservoirs in terms of the first and second laws of thermodynamics. Citing relevant references from the literature, we propose a methodology that can improve the thermodynamic analysis of an energy-transforming or an exergy-destroying plant. Through the reflections and analysis presented, we have found an explanation of the second law that clarifies the link between the Clausius integral of heat over temperature and the reference temperature of the Gouy–Stodola theorem. With this insight and approach, the specification of the environmental reference temperature in exergy analysis becomes more solid. We have explained the relationship between the Curzon Ahlborn heat engine and an irreversible Carnot heat engine. We have outlined the nature of subsystem rational efficiencies and have found Rant’s anergy to play an important role. We postulate that heat transfer through thermal resistance is the sole basis of irreversibility. View Full-Text
Keywords: anergy; Clausius inequality; exergy; finite time thermodynamics; Gouy–Stodola theorem; irreversible thermodynamics; rational efficiency; reference temperature; second law; thermal resistance anergy; Clausius inequality; exergy; finite time thermodynamics; Gouy–Stodola theorem; irreversible thermodynamics; rational efficiency; reference temperature; second law; thermal resistance
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McGovern, J. Thermodynamic Analysis of Closed Steady or Cyclic Systems. Entropy 2015, 17, 6712-6742.

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