On the Clausius equality and inequality

Self Cite

We present the fundamental equation for a system and for a process, and by considering irreversibility within the system, we show that the lost work concept emerges naturally from the formalism. We then argue that if irreversibility is considered within the surroundings the lost work becomes what is known as exergy. Therefore, lost work and exergy are two views of the same concept, which in turn integrates a broader and more fundamental concept: entropy generation. It is our opinion that the clarification of the meanings of lost work and exergy, as well as the discussion that leads to an understanding of their differences and similarities, has not received the attention in the literature that it deserves. This paper fills that gap, and it is hoped that the discussion of these two concepts here will be useful for both students and teachers.

Section: Irreversibility In the System And Lost Worksupporting

confidence: 86%

Lost work and exergy: two views of the same concept

Anacleto

2024

Self Cite

“…which, from (9b) and (10), can also be written as where the former sign corresponds to reversible processes and the latter to irreversible ones [10].…”

Section: **mentioning

confidence: 99%

Adiabatic and thermally insulated: should they have the same meaning?

Anacleto¹,

Ferreira²

2017

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“…e e e e which is a very interesting and powerful relation as it encompasses state variables of both system and surroundings [6][7][8]. Considering that surroundings consist of heat and/or work reservoirs [7], each term in the above relation has a precise meaning as follows [7,8]: the first and second terms in the rhs of (3) are, respectively, the work δW and heat δQ…”

Section: Reversible Versus Quasistaticmentioning

confidence: 99%

On the representation of thermodynamic processes

Anacleto

Ferreira

2015

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We discuss the representation of thermodynamic processes in diagrams. Although the idea that it is impossible to represent non-quasistatic processes is correct and consensual, it is surprising that we sometimes find in the literature such processes represented somehow, in contradiction with, for instance, the concept of equilibrium state. At other times, the justification given for process representation does not help clarify the difference between reversible and quasistatic processes. In this paper we address the errors inherent to such procedures and also, paradoxically, propose the representation of non-quasistatic processes using the concept of identical processes.