Experimental investigation on off-design performance and adjustment strategies of the centrifugal compressor in compressed air energy storage system

Abstract

The compressor used in compressed air energy storage (CAES) system usually operates under off-design conditions due to load fluctuations, environmental factors, and performance characteristics of the system. Two stabilization techniques, named adjustable inlet guide vanes (AIGVs) and adjustable vaned diffusers (AVDs), are experimentally investigated in a centrifugal compressor, and their adjustment strategies are reported in this paper. First, the impact of these two adjustment methods on the compressor performance is presented. The pressure ratio range of the compressor can be expanded by 207.3% through adjusting AIGVs, and 72.6% through adjusting AVDs, respectively. Second, the optimum operating lines and adjustment strategies of the compressor are obtained according to its working characteristics. Last, the Kriging interpolation model and Nelder-Mead algorithm are employed to find the optimal strategies of the combined adjustment of AIGVs and AVDs. The results show that the combined adjustment of AIGVs and AVDs enables an increase in pressure ratio range by 232.5%, and the maximum efficiency is increased by 1.2% compared with the condition that adjustment is absent. The present research provides an effective method for compressor operation and control in CAES system.