Impacts of solar multiples on the performance of integrated solar combined cycle systems with two direct steam generation fields

This paper presents the thermodynamic and economic analysis for an ISCC system with two pressure level DSG solar fields (ISCC-2DSG), aiming to study the impacts of solar multiples on system performance with or without consideration of thermal storage. In the ISCC-2DSG system, the solar thermal energy produced from two solar fields is only used to supply latent heat for low- and high-pressure water vaporization, respectively. Feedwater preheating and steam superheating are achieved in a HRSG. The annual thermodynamic performance of several such ISCC-2DSG systems, with different solar multiple values but with identical design parameters in the power subsystem, is characterized. Based on these features, the LEC for each system is calculated and compared. An optimum solar field size (solar multiple), which gives the minimum LEC, for the ISCC-2DSG system can be finally obtained.