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Ebook Thermodynamics an engineering approach (4th edition): Part 2

(BQ) Part 2 book "Thermodynamics an engineering approach" has contents: Vapor and combined power cycles, refrigeration cycles; thermodynamic property relations; gas mixtures; gas-vapor mixtures and air conditioning; chemical reactions; chemical and phase equilibrium; compressible flow. | cen84959_ch10.qxd 4/19/05 2:17 PM Page 551 Chapter 10 VAPOR AND COMBINED POWER CYCLES I n Chap. 9 we discussed gas power cycles for which the working fluid remains a gas throughout the entire cycle. In this chapter, we consider vapor power cycles in which the working fluid is alternatively vaporized and condensed. We also consider power generation coupled with process heating called cogeneration. The continued quest for higher thermal efficiencies has resulted in some innovative modifications to the basic vapor power cycle. Among these, we discuss the reheat and regenerative cycles, as well as combined gas–vapor power cycles. Steam is the most common working fluid used in vapor power 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 discussion of steam power plants. Steam power plants are commonly referred to as coal plants, nuclear plants, or natural gas plants, depending on the type of fuel used to supply heat to the steam. However, the steam goes through the same basic cycle in all of them. Therefore, all can be analyzed in the same manner. Objectives The objectives of Chapter 10 are to: • Analyze vapor power cycles in which the working fluid is alternately vaporized and condensed. • Analyze power generation coupled with process heating called cogeneration. • Investigate ways to modify the basic Rankine vapor power cycle to increase the cycle thermal efficiency. • Analyze the reheat and regenerative vapor power cycles. • Analyze power cycles that consist of two separate cycles known as combined cycles and binary cycles. | 551 cen84959_ch10.qxd 4/19/05 2:17 PM Page 552 552 | Thermodynamics 10–1 THE CARNOT VAPOR CYCLE ■ We have mentioned repeatedly that the Carnot cycle is the most efficient cycle operating between two specified temperature limits. Thus it is natural to look at the Carnot cycle first as a prospective ideal cycle .