Synthesis and optimization approach for integrated solar combined cycle systems based on pinch technology. Part I. Heat recovery pressure levels

Integrated solar combined cycle systems (ISCCS) represent, both economicall y and energetically, a promising alternative for the conversion of solar en ergy while offering a guarantee of a minimum power supply independent of th e level of solar radiation. Their performances are, however, strongly depen dent on the intensity of the solar input. The approach proposed in this pap er allows, from the characteristics of the turbines (gas turbines and steam turbines) and of the solar field, to rationalize the choice of the pressur e levels and of the massflows of a steam cycle with multiple pressure level s. It is based on the coupling of a pinch technology approach with a thermo dynamic modelling, allowing an optimisation with deterministic algorithms. Results are applied to a dual pressure steam cycle and account for the resp ect of the 'cone law' for steam turbines. It is shown that an increase of t he exergetic losses linked to heat transfer in the steam generators is inev itable at certain operational regimes and depends directly on the level of solar supply. The variations of the main steam cycle parameters as a functi on of the thermal supply (combustion gases + solar thermal oil) are shown f or an 80 to 120 MWe power plant equipped with two gas turbines and one stea m turbine train. (C) Elsevier, Paris.