Page 4 - Advanced thermodynamics for engineers

Preface – First Edition

When reviewing, or contemplating writing, a text-book on engineering thermodynamics, it is neces-
sary to ask what does this book offer that is not already available? The author has taught thermody-
namics to mechanical engineering students, at both undergraduate and postgraduate level, for
25 years, and has found that the existing texts cover very adequately the basic theories of the subject.
However, by the final years of a course, and at postgraduate level, the material which is presented
is very much influenced by the lecturer, and here it is less easy to find one book which covers all
the syllabus in the required manner. This book attempts to answer this need, for the author at least.
The engineer is essentially concerned with manufacturing devices to enable tasks to be performed
cost-effectively and efficiently. Engineering has produced a new generation of automatic ‘slaves’
which enable those in the developed countries to maintain their lifestyle by the consumption of fuels
rather than by manual labour. The developing countries still rely to a large extent on ‘manpower’, but
the pace of development is such that the whole world wishes to have the machines and quality of life
which we, in the developed countries, take for granted: this is a major challenge to the engineer, and
particularly the thermodynamicist. The reason why the thermodynamicist plays a key role in this sce-
nario is because the methods of converting any form of energy into power are the domain of thermo-
dynamics: all of these processes obey the four laws of thermodynamics, and their efficiency is
controlled by the second law. The emphasis of the early years of an undergraduate course is on the
first law of thermodynamics, which is simply the conservation of energy; the first law does not
give any information on the quality of the energy. It is the hope of the author that this text will intro-
duce the concept of the quality of energy and help future engineers use our resources more efficiently.
Ironically, some of the largest demands for energy may come from cooling (e.g. refrigeration and air-
conditioning) as the developing countries in the tropical regions become wealthier – this might require
a more basic way of considering energy utilisation than that emphasised in current thermodynamic
texts. This book attempts to introduce basic concepts which should apply over the whole range of
new technologies covered by engineering thermodynamics. It considers new approaches to cycles,
which enable their irreversibility to be taken into account; a detailed study of combustion to show
how the chemical energy in a fuel is converted into thermal energy and emissions; an analysis of
fuel cells to give an understanding of the direct conversion of chemical energy to electrical power;
a detailed study of property relationships to enable more sophisticated analyses to be made of both
high and low temperature plant; and irreversible thermodynamics, whose principles might hold a
key to new ways of efficiently converting energy to power (e.g. solar energy, fuel cells).
The great advances in the understanding and teaching of thermodynamics came rapidly towards the
end of the nineteenth century, and it was not until the 1940s that these were embodied in thermody-
namics textbooks for mechanical engineers. Some of the approaches used in teaching thermodynamics
still contain the assumptions embodied in the theories of heat engines without explicitly recognising
the limitations they impose. It was the desire to remove some of these shortcomings, together with an
increasing interest in what limits the efficiency of thermodynamic devices, that led the author down the
path which has culminated in this text.
I am still a strong believer in the pedagogical necessity of introducing thermodynamics through the
traditional route of the zeroth, first, second and third laws, rather than attempting to use the Single-
Axiom Theorem of Hatsopoulos and Keenan, or The Law of Stable Equilibrium of Haywood. While

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