ABSTRACT
In Chapter 1 a power plant cycle was used to illustrate the case where the working substance passes through several thermodynamics processes, viz., one of heating, one of cooling and another of work production. All of these processes involve changes in the thermodynamic state of the working substance. The substance may also change form or phase, e.g., in a power plant the boiler changes water in a liquid phase to steam which is a vaporous or a gaseous phase of water, or the substance may remain in the same phase while changing its temperature, pressure or volume, e.g., water in the pump is compressed before it flows into the boiler. Almost always the substance, or system, undergoing a thermodynamic process will incur a change in the energy content; all of the aforementioned characteristics used to describe the condition or state of the working substance are known as thermodynamic properties, e.g., pressure, temperature, specific volume, density and specific internal energy previously introduced in Chapter 1.
