Thermodynamic Processes and Engines

Abstract

This chapter starts with the treatment of changes of state in practical applications where the quasistatic conditions are not fulfilled; the nature of spontaneous and irreversible processes is discussed, compared to reversible processes. In the main part of the chapter, heat engines, refrigerators and heat pumps are described in detail. The treatment is based on equilibrium calculations; irreversibility is only considered as losses due to the nonquasistatic nature of the operation. As the complete thermodynamic formalism is already described in previous chapters, a rather straightforward formulation of heat transfer and energy production, along with the state-function property of energy and entropy enables an easy calculation of the efficiency and the coefficient of performance of practical devices. Besides the necessary treatment of the theoretically important Carnot engines, the Rankin cycle and practical devices based on this cycle are described in details. At the end of the chapter, a detailed thermodynamic analysis of the Joule–Thomson effect is also given, due to its importance in refrigerators and gas liquefiers.