Simulation of Solarized Combined Cycles: Comparison Between Hybrid Gas Turbine and ISCC Plants

Abstract

The present paper investigates two different solarized combined cycle layout configurations. In the first scheme, a solarized gas turbine is coupled to a solar tower. Pressurized air at the compressor exit is sent to the solar tower receiver before entering the gas turbine (GT) combustor. Here, temperature is increased up to the nominal turbine inlet value through natural gas combustion. In the second combined cycle (CC) layout, solar energy is collected by line focusing parabolic trough collectors and used to produce superheated steam in addition to the one generated in the heat recovery boiler. The goal of the paper is to compare the thermodynamic performance of these concentrating solar power (CSP) technologies when working under realistic operating conditions. Commercial software and in-house computer codes were combined together to predict CSP plant performance both on design and off-design conditions. Plant simulations have shown the beneficial effect of introducing solar energy at high temperature in the Joule–Brayton cycle and the drawback in terms of GT performance penalization due to solarization. Results of yearly simulations on a 1 h basis for the two considered plant configurations are presented and discussed. The main thermodynamic parameters such as temperatures, pressure levels, and air and steam flow rates are reported for two representative days.