Page 18 - Advanced thermodynamics for engineers

CHAPTER
1
INTRODUCTION AND REVISION

1.1 THERMODYNAMICS
Thermodynamics is the science which defines the relationship between different forms of energy via
characterisations of the various attributes of the enclosing system. This energy can take the form of
work, heat or the energy contained within a system. Engineering thermodynamics plays a major role in
the consideration of power generation, air-conditioning, chemical reactions, cryogenics (low
temperatures) and low pressure systems. In general, thermodynamic concepts can be applied over a
whole range of sciences, including biological systems, and they govern the way in which energy can be
transformed between its various forms.
This chapter will briefly reiterate the fundamentals of the subject to make the reader familiar with
the vocabulary and symbols used in this book. A more detailed version of this chapter, and its
associated problems, is available on the website: http://booksite.elsevier.com/9780444633736.

1.1.1 MACROSCOPIC THERMODYNAMICS
There are two basic methods of studying thermodynamics, termed classical (or macroscopic) and
statistical thermodynamics. Classical thermodynamics concentrates on the net changes affecting a
system, without considering the detailed changes occurring within the system and the enclosing
boundaries. Statistical thermodynamics considers the detailed changes occurring to and within the
molecules inside the system, and can be termed microscopic thermodynamics. This book will
concentrate on macroscopic thermodynamics, however, some concepts of statistical thermodynamics
will be used to explain certain phenomena (see Chapter 21).
Classical thermodynamics considers systems at, or close to, equilibrium: many of the simple
applications of thermodynamics are covered under this restriction. Notable cases which are not
included in equilibrium situations are the production of pollutants (e.g. carbon monoxide and oxides of
nitrogen) in combustion processes along with a large number of industrially important physico-
chemical processes.

1.1.2 LAWS OF THERMODYNAMICS
There are four laws of thermodynamics, which have been developed from observations of large
numbers of experiments. These laws are termed axioms (self-evident truths), and are the following:
Zeroth Law of Thermodynamics, which defines the concept of temperature.
First Law of Thermodynamics, which defines the concept of energy.
Advanced Thermodynamics for Engineers. http://dx.doi.org/10.1016/B978-0-444-63373-6.00001-0 1
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