Load-tracking performance optimization for a supercritical CO₂ recompression cycle under bypass control utilizing variable turbine inlet guide vanes

The study evaluates the impact of integrating a turbine equipped with variable inlet guide vanes (VIGVs) on system performance under turbine and heater bypass controls. It discusses effective methods for tuning turbine guide vanes and optimizes the system's load-tracking capabilities. Key results indicate that the turbine bypass mode is more effective than the heater bypass mode, reducing system heat input by increasing the CO₂ temperature entering the heater. Optimization shows that the positive and negative rotation of the turbine inlet guide vanes improves thermal efficiency by 6.23% and 6.49% in turbine bypass and heater bypass modes, respectively, at a 10% load ratio. As the load ratio decreases, optimal vane rotation angles increase to enhance load-tracking thermal efficiency, with heater bypass control showing a more significant impact on vane rotation. Additionally, using the VIGVs-fitted turbine eliminates heater bypass flow when load ratios are 80% or higher.