Matching performance analysis method of multi-compressor series-parallel system for compressed air energy storage

The multi-compressor series-parallel system is widely applied in compressed air energy storage (CAES), where it faces complex off-design conditions and often highly simplifies the modelling of compressor performances and operations. This paper presents a matching analysis method for multi-compressor series-parallel systems based on two-dimensional (2D) through-flow method to predict accurately the impact of choking, stall and other operation limits on efficiency and reliability. A prediction tool is developed integrating 2D streamline curvature (SLC) codes for compressors with 1D models for pipeline components. Matching Analysis of compressors with variable rotational speed and guide vanes is conducted for a CAES compression system under typical loadings. Feasible operational windows with optimized operation points are identified accounting for efficiency and stall margin. Matching performance and control strategies for start/stop processes of the system is analyzed, incorporating regulation of rotational speed, variable guide vanes (VGVs) and bypass bleeding. A reliable strategy for compressors is proposed to achieve synchronized startup based on quasi-steady analysis. This analysis method provides theoretical guidance for design, operation, and control of multi-compressor series-parallel systems in CAES applications. • Matching analysis method is proposed for multi-compressor series-parallel systems. • 2D through-flow method of axial compressors is integrated with 1D pipeline models. • Performance of varied operation modes is analyzed for a CAES compression system. • Feasible operation windows with optimized schemes are predicted at typical loadings. • Control strategies are developed to achieve synchronized start/stop processes.