Thermodynamic Modeling and Comprehensive Off-design Performance Analysis of a Real Integrated Solar Combined Cycle Power Plant

In this paper, a thermodynamic modeling and a comprehensive performance analysis of a real integrated solar combined cycle (ISCC) power plant are performed. The performance of the plant cycle is assessed in an off-design condition and in two operation modes of power-boosting and of fuel-saving. Such an approach has not been considered for an ISCC plant in previous studies. Yazd ISCC, as a case study, consists of parabolic collectors which are connected to a combined cycle section. The presented simulation results cover different times of the day and the twelve months of the year. According to these results, in the power-boosting mode, the steam production of the fossil section is reduced by 12 kg/s from 6:00 AM to 3:00 PM on the design day while the solar steam increases by 36 kg/s. By stabilizing the oil temperature on 392°C, the control philosophy of the starting of steam production in the solar field is also discussed. In the fuel-saving mode, if the solar field is in service, the fuel consumption of the auxiliary burners is reduced by 28,000 kg on the design day. The results of this paper indicate that the power output of ISCCs is more stable than the conventional combined cycles on the hot days of the year.