ABSTRACT
The purpose of auditing and retrofitting is to save energy. To do so, it is important to understand the concept of energy and what it entails. This chapter discusses the following concepts of energy: potential and kinetic energy, the first two laws of thermodynamics, the relationship of energy to heat, work and temperature, phase change, and heat transfer. Electrical energy running along a transmission line has kinetic energy that originated at a dam, coal plant, etc. using the potential energy of the water behind a dam, the fossil fuel energy stored in coal or other sources, to create the electricity. In the middle of changing phases, such as going from ice to liquid water or from liquid water to steam, energy or heat has to be added just to get the water to change from one state to another.
