Thermodynamics

Chapter 10VAPOR AND COMBINED POWER CYCLESIn Chap. 9 we discussed gas power cycles for which theworking fluid remains a gas throughout the entire cycle. Inthis chapter, we consider vapor power cycles in which theworking fluid is alternatively vaporized and condensed. Wealso consider power generation coupled with process heatingcalled cogeneration.The continued quest for higher thermal efficiencies hasresulted in some innovative modifications to the basic vaporpower cycle. Among these, we discuss the reheat and regenerativecycles, as well as combined gas–vapor power cycles.Steam is the most common working fluid used in vaporpower cycles because of its many desirable characteristics,such as low cost, availability, and high enthalpy of vaporization.Therefore, this chapter is mostly devoted to the discussionof steam power plants. Steam power plants are commonlyreferred to as coal plants, nuclear plants, or natural gasplants, depending on the type of fuel used to supply heat tothe steam. However, the steam goes through the same basiccycle in all of them. Therefore, all can be analyzed in thesame manner.ObjectivesThe objectives of Chapter 10 are to:• Analyze vapor power cycles in which the working fluid isalternately vaporized and condensed.• Analyze power generation coupled with process heatingcalled cogeneration.• Investigate ways to modify the basic Rankine vapor powercycle to increase the cycle thermal efficiency.• Analyze the reheat and regenerative vapor power cycles.• Analyze power cycles that consist of two separate cyclesknown as combined cycles and binary cycles.| 551