Proposal and analysis of an integrated solar combined cycle with partial recuperation

The paper analyses an integrated solar combined cycle that, as a novelty, includes a gas turbine with partial recuperation. A conventional solar arrangement including parabolic troughs with a thermal oil is assumed. This field feeds a solar steam generator working in parallel with the high-pressure evaporator of the heat recovery steam generator. The plant is designed to balance out the solar supply to the steam cycle with the thermal power transferred to the air in the recuperator before it is introduced in the combustion chamber. Thus, only a fraction of the turbine exhaust gas flows through the recuperator. The additional steam production due to the solar contribution is mitigated by lower power available at the evaporator of the heat recovery steam generator, making possible to achieve constant steam turbine operation regardless the solar contribution. Results show that the proposal reaches better performance and lower generating cost than conventional integrated solar combined cycles. Besides, a new proposal to evaluate plant performances and economical assessments is introduced, which has been shown useful to understand correctly the results obtained. (C) 2020 The Authors. Published by Elsevier Ltd.