Multidirectional research and optimization of the dynamics of gas expansion in the complex of the mechanical and thermal energy storage and the expander for micro-CAES (compressed air energy storage)

• Applicant: Professor Dr.-Ing. Oliver Sawodny
• Subject Area: Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 564468515

The project deals with the fundamentals of the exergy efficiency of the thermodynamic processes of gas expansion in micro compressed air energy storage systems (CAES), which could theoretically reach 85%, but have so far only achieved around 60% in experimental studies. The overall goal is to maximize the exergy efficiency of the process of converting the thermomechanical expansion energy of the compressed gas into electricity. The main hypotheses are: 1. the impinging pressure of the compressed gas has a feedback effect on the dynamics of the compression cylinder; 2. the cyclically pulsed compressed air supply reduces the air mass flow and expansion losses caused by a different storage pressure in the compressed air reservoir in relation to the working pressure in the expander. 3. exhaust gas recirculation at the outlet of the expander increases the efficiency of the system. Further research questions are: It has been shown that additional thermal energy storage increases exergy efficiency during gas expansion, but what is the influence of residence time and location of heat transfer on exergy efficiency and piston dynamics? How can methods of system dynamics contribute to the system design of the expander and the compressed air accumulator? In the project, a compressed air energy storage system consisting of compressed air storage, expander unit and heat recovery system will be investigated and optimized in terms of energy efficiency. The results will be validated experimentally on a test rig.

• DFG Programme: Research Grants
• International Connection: Poland
• Cooperation Partner: Professor Dr.-Ing. Jacek Leszczynski