Solar hybrid steam-injected gas turbine system with novel heat and water recovery

Abstract

For concentrating solar power, Brayton cycle offers a more attractive method than Rankine cycle to improve the flexibility and the efficiency of electricity production and peak-load regulation. Therefore, in this study, a solar hybrid steam-injected gas turbine system with novel heat and water recovery is proposed. The new system injects steam at the inlet of a turbine and recovers waste heat and water from exhaust gas. Thermodynamic models of the novel system are built to analyze main factors that affect the performance and characteristics. The system efficiency is improved by 17% under an optimal steam injection rate of 0.065. Water recovery rates reach up to 98%, which is associated with a high waste heat recovery rate from the exhaust gas. Compared with a single-stage absorption refrigeration unit, the heat recovery rate and refrigeration capacity of the system with a double-stage absorption refrigeration unit are increased by 109% and 63%, respectively. Furthermore, the models are applied to analyze the annual performance and environmental sustainability of the novel system in Lhasa and Dunhuang, western China. The maximum efficiency and peak power output of the novel system are increased by 21.8% and 37.9%, respectively. The consumption of fuels and emissions of CO2 is lower than conventional gas turbine. These results indicate that the proposed system shows high efficiency possibility and environmental sustainability with a near-zero water consumption.