1.1 Energy Units, Conversions, and Dimensional Analysis

This chapter provides energy units, conversions, and dimensional analysis. After a brief introduction, the chapter discusses base and derived quantities, relationships between quantities, and quantity equations. There are three basic types of quantity equations, namely, the quantity equations developed from the laws of nature, the equations developed from geometry, and the equations developed from a definition; and all are discussed and analyzed in this chapter. Then, the 20 multiples and submultiples in the SI unit system are presented. And then, an introduction is presented for dimensional analysis, which is quite a useful method for deriving an algebraic relationship between different physical quantities. The idea behind this analysis is that each variable is expressed in terms of its fundamental units of mass M , length L , and time T , etc., raised to some arbitrary index a, b, c, etc. These unknown indices are then determined by equating the indices of like units. And then, the Standard for Metric Practice, ASTM Standard E 380-84, as one of the basic standards, is referenced for SI usage. Furthermore, conversion factors for energy related units rounded to three or four significant figures for conversion between SI and I–P are provided, as well as conversion factors for different physical quantities related to energy further. Finally, the chapter is concluded with some illustrative examples of unit conversions and dimensional analyses.