Design Point and Off-Design Simulation of a Gas Turbine–Solar Power Plant

The integration of solar energy into gas turbine cycles represents a promising approach to enhance system efficiency and reduce fossil fuel consumption. In this study, a single-shaft gas turbine–solar hybrid power plant is simulated under both design-point and off-design conditions and analyzed from energy and exergy perspectives. The model incorporates a compressor, turbine, combustion chamber, heat exchanger, and solar receiver, while the influence of key parameters such as compressor pressure ratio, turbine inlet temperature, and solar irradiation is investigated. The results reveal that solar energy utilization reduces fuel consumption and lowers exergy destruction within the combustion chamber. Off-design simulations further demonstrate that variations in rotational speed and solar irradiation significantly affect power output, fuel consumption, and overall efficiency. Increasing the compressor speed enhances the mass flow rate of air and requires additional fuel to maintain the air–fuel ratio, thereby increasing the output power but simultaneously raising fuel consumption and reducing thermal efficiency.