In this introductory chapter, we discuss some of the reasons for the study of heat transfer (applications and history), introduce the units used in heat transfer analysis, and give definitions for the thermal systems. Then we discuss the heat flux vector q, the heat transfer medium, the equation of conservation of energy (with a reformulation that places q as the central focus), and the equations for conservation of mass, species, and other conserved quantities. Finally we discuss the scope of the book, i.e., an outline of the principles of heat transfer, and give a description of the following chapters and their relations. Chart 1.1 gives the outline for this chapter. This introductory chapter is partly descriptive (as compared to quantitative) in order to depict the broad scope of heat transfer applications and analyses.

Applications and History

Heat transfer is the transport of thermal energy driven by thermal nonequilibrium within amedium or among neighboringmedia. As an academic discipline, it is part of the more general area of thermal science and engineering. In a broad sense, thermal science and engineering deals with a combination of thermal science, mechanics, and thermal engineering analysis and design. This is depicted in Chart 1.2. In turn, thermal science includes thermal physics, thermal chemistry, and thermal biology.