Conventional and Alternative Power Generation

2Vapour Power Cycles

2.1 Overview

The majority of power stations rely on phase changes in a working fluid such as water to provide power. Thermodynamic analyses such as the Carnot cycle and the Rankine cycle are employed in order to calculate the power output and efficiency of thermal conversion. This chapter will introduce the basic power cycles and examine enhancements that increase overall efficiency.

Learning Outcomes

• To understand the basic vapour cycles and demonstrate the limitation of the hypothetical Carnot cycle.
• To understand the practical amendments used to improve steam cycle efficiency.
• To understand the concept of the Organic Rankine cycle.
• To be able to appraise combined heat and power (CHP), trigeneration and quad generation.
• To be able to solve problems related to steam cycles.

2.2 Steam Power Plants

A power plant is an installation for the production of electrical energy. A steam power plant utilizes the heat released during the combustion of fuel to heat water flowing inside tubes, thus transforming it into steam, which is subsequently allowed to expand in a turbine unit especially designed with rows of blades absorbing the energy of the steam. The mechanical (rotational) energy of the turbine is converted into electrical energy by the generator that is mounted on the same shaft as the turbine unit. A typical steam power plant is shown in Figure 2.1.

Figure 2.1 Typical ...