Modeling and Analysis of a Hybrid Solar-Dish Brayton Engine

Small-scale recuperated gas turbines with a highly efficient recuperator would appear to have considerable potential to be used in solar/fossil-fuel hybrid dish systems. The hybrid solar gas turbine can be configured in several different fashions, with the key difference being the relative positions of the solar receiver and burner as well as the operation mode of the burner.Steady state and transient models have been implemented in Engineering Equation Solver and the performance of various configurations are studied and compared. Layouts in which the receiver is located before the turbine (pressurized receivers) demonstrate higher performance compared to the one in which the receiver is located after the turbine (atmospheric receivers). The variation in operation throughout the year is taken into account and the performance of the system analyzed for two different cities (Yechang in China and Bechar in Algeria, with low and high solar insolation respectively). The integration of a solar receiver into a micro gas turbine reduces the yearly fuel consumption by around 15-16% in Yechang and up to 40% in Bechar. This will result in reductions of CO2 emissions as well as leading to lower daily operating costs. The hybrid nature of the Dish-Brayton system guarantees availability of the engine to meet the electricity demand whenever it occurs, allowing the system to supply dispatchable power.