INVESTIGATION OF DIFFERENT SOLAR HYBRID GAS TURBINES AND EXPLOITATION OF REJECTED SUN POWER

摘要

Solar hybrid gas turbine performance is studied through consideration of four engine configurations: a) single shaft, b) recuperated single-shaft, c) twin-shaft and d) two-spool three-shaft, intercooled, recuperated. For each configuration and for the same design point, the performance is obtained for two hybridization schemes: Fuel only engines Retrofitted for Solar operation (FRS) and engines designed with Solar only operation at the Design Point (SDP). In an attempt to further improve the benefits of hybridization, the concept of a Dual Fluid Receiver for exploiting the rejected solar power, during sunny hours with high irradiation, is demonstrated. Steam is produced by focusing the defocused mirrors of the heliostat field to a second receiver and injected into the combustion chamber. For the cases examined, it can be concluded that FRS engines show better performance than SDP ones, since they exhibit higher thermal fuel efficiency and higher specific power. Concerning the configurations, an annual fuel saving of～35% and an annual output reduction, ranging from 4% for the recuperated single-shaft configuration to 9% for the twin shaft configuration compared to the corresponding fuel-only engines is demonstrated. The inclusion of a Dual Fluid Receiver in an FRS engine removes the power penalty while it maintains the fuel saving benefit.