Deakin University 2003
Introduction and basic
Throughout this topic you will need to refer to chapter 1 in your textbook.
Thermodynamics is the science of energy in its different forms, and methods
of converting one form of energy into another in the most efficient way
possible. There are many examples of this energy conversion process. Chapter
1 in your textbook gives some examples of energy conversion processes so it
would be a good idea to start reading through it now.
Currently, research work is being conducted on several energy conversion
devices, such as fuel cells that convert chemical energy directly into electrical
energy, nuclear fusion, photovoltaic cells, and so on. Also under investigation
are several other processes that will efficiently utilise energy from tidal waves,
wind, the sun, coal, and high temperature, high pressure water beneath the
crust of the earth. It is interesting to note that although the steam engine—the
first energy conversion device to have a profound impact on mankind—was
well developed by the early part of the eighteenth century, the laws of
thermodynamics were not clearly understood until about 100 years later.
The concept of energy, along with its conservation and convertibility, evolved
in an effort to present a unified approach for the analysis of these apparently
unrelated phenomena. It is now known that in the absence of nuclear reactions,
energy is conserved and that energy cannot be created or destroyed. This
represents the First Law of Thermodynamics. Also, any form of energy can be
completely converted into thermal energy or heat energy, but thermal energy
cannot be completely converted into other forms of energy. This observation is
the basis of the Second Law of Thermodynamics. The laws of
thermodynamics play an important role in the design of a wide range of
devices, such as automotive engines, air conditioners, rocket motors, high-
power lasers, refineries and windmills.
Thermodynamics is studied by physicists, chemists and engineers. Physicists
and chemists are concerned with basic laws, properties of substances, and
changes in the properties caused by interaction of different forms of energy.
Engineers are interested not only in all these aspects, but also in the
application of thermodynamic principles to the design of machines that will
convert energy from one form into another. Electrical engineers are often
interested in the conversion of mechanical energy into electrical energy.