The Combined First and Second Law of Thermodynamics, Availability, and Sample Problems

Abstract

The material presented in this lecture is adapted from Chapter 4 of T&M. First, we will derive the Combined First and Second Law of Thermodynamics for both a closed and an open, single-phase, simple system. Second, we will solve Sample Problem 11.1 which will help us crystallize the material presented in Lecture 10, including calculating changes in entropy and changes in energy, heat, and work when a gas expands isothermally in a cylinder-piston assembly, without friction, in one case, reversibly, and in another case, irreversibly. Finally, we will solve Sample Problem 11.2 to calculate the maximum work done by an open system, consisting of shaft work and Carnot work, including introducing a new thermodynamic function of state, the Availability or Exergy.