Case Study: Turbomachines for Concentrating Solar Power Plants

In this chapter numerical applications of the procedures proposed in the previous chapters are illustrated: from the turbomachinery selection process (Chap. 2) to their preliminary design (Chaps. 3– 7). The Concentrating Solar Power (CSP) sector has been chosen in order to provide design examples of turbomachinery operating with unconventional fluids (that is, fluids different from air, water, steam and flue gas used in conventional steam cycles, gas turbines and combined cycles). We will analyze power blocks integrated in a solar field equipped with a central tower; in this application, Brayton closed cycles, operating with Helium, Argon or supercritical CO2 (sCO2), are proposed, alone or in combination with Organic Rankine Cycles (ORC) fed by the waste heat of the Brayton cycle. First of all, we will analyze these cycles evaluating their performance and sizing 10 MWe power blocks (Sect. 8.1). Knowing the flow rates handled by turbomachines as well as their inlet and outlet conditions (inlet pressure and temperature, and outlet pressure) we will proceed (Sect. 8.2) to the selection and preliminary design of each turbomachine. It is important to highlight that when defining the thermodynamic cycle of each power block, we assume the turbomachinery efficiency; but this efficiency must necessarily be verified through the loss calculation, which requires knowledge of the kinematics, the thermodynamics and the geometry of the turbomachines (Chaps. 3– 7 and this chapter), especially considering the working fluids used in these CSP applications. Otherwise, the cycle performance assessment is not realistic.