Parametric analysis of thermal losses on hybrid solar gas-turbine power plants

Abstract

In this paper a parametric analysis of thermal and pressure losses for a hybrid Brayton thermosolar plant is carried out. A serial hybridization is modelled with the purpose of delivering an stable power output. A purely thermodynamic model describing this sort of facilities is presented. The model is general and flexible, so it is easily applicable to different plant configurations (hybrid or pure combustion modes). The overall system is considered as formed by three subsystems linked by heat exchangers: solar collector, combustion chamber, and recuperative Brayton gas-turbine. All the main irreversibility sources existing in real installations are assumed by the subsystem models. For numerical calculations, particular parameters from a real installation and actual meteorological data are taken (solar irradiance and ambient temperature are yearly averaged). Later, a sensitivity analysis is accomplished, in which both solar and turbine subsystems are examined, being the optical efficiency of the heliostat field and the turbine efficiency, respectively, the most influential variables. This kind of studies could be a guideline for the design of future hybrid gas-turbine thermosolar facilities.