Conventional and advanced exergy analyses of an underwater compressed air energy storage system

• Published in: Applied energy 2016-10, Vol.180, p.810-822
• Main Authors: Wang, Zhiwen, Xiong, Wei, Ting, David S.-K., Carriveau, Rupp, Wang, Zuwen
• Format: Article
• Language: English
• Subjects: Advanced exergy analysis; Compressed air energy storage; Energy storage; Exergy; Exergy destruction; Underwater
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2016.08.014

•Advanced exergy analysis is conducted on UWCAES for the first time.•Detailed exergy destruction information is delineated.•The analysis shows that UWCAES has great potential for performance improvement.•The interactions among the components are found to be weak but interwoven.•The advanced exergy analysis presents different and more pragmatic results. A 2MW underwater compressed air energy storage (UWCAES) system is studied using both conventional and advanced exergy analyses. The exergy efficiency of the proposed UWCAES system is found to be 53.6% under the real conditions. While the theoretical maximum under the unavoidable condition is 84.3%; showing a great potential for performance improvement. Even though there are quantitative differences between conventional and advanced results, both show that the final compressor stage has the highest potential for improvement. The advanced exergy analysis reveals the real improvement potential of the UWCAES system. Further, it is revealed that the interactions between system components are complex but not very strong. Subsequently, the total exergy efficiency may not necessarily increase by improving the performance of the components individually.