The science of thermodynamics is formally defined as the study of energy and its transformations. “Thermo” is defined as heat or energy and “dynamics” is defined as changes. That means thermodynamics is a study of changes in energy. Thermodynamics is one of the most fundamental of the physical sciences and many have seen it as a beautiful and coherent way to describe the natural world. No less an authority than Albert Einstein said:
A theory is more impressive the greater is the simplicity of its premises, the more different are the things it relates, and the more extended its range of applicability. Therefore, the deep impression which classical thermodynamics made on me. It is the only physical theory of universal content which I am convinced, that within the framework of applicability of its basic concepts, will never be overthrown.
Engineering thermodynamics is the application of thermodynamic principles to solve engineering problems related to mass, work, energy and power. Doing so requires knowledge of thermodynamic concepts and definitions; thermodynamic properties of substances; classification of energy into its various forms; and the laws governing energy conservation and transformation. In this introductory chapter, important definitions and concepts are introduced that will be used throughout the text.