Compressed Air Storage

COMPRESSED AIR STORAGE

Micro compressed-air energy storage (micro-CAES) is a promising technology for storing electricity from fluctuating renewable energy sources, particularly in small-scale and off-grid applications. However, current systems are limited by comparatively low round-trip efficiencies caused by pressure fluctuations during discharge, thermal losses during compression and expansion, and inefficient or insufficiently controllable expanders.

The project investigates how the conversion of thermomechanical energy stored in compressed gas into electrical energy can be improved. A particular focus is placed on the interaction between mechanical energy storage, thermal energy storage and the expander. Instead of conventional pressure reduction, cyclic-pulsed compressed gas injection is investigated to transfer energy and momentum directly to the expander piston. In parallel, different concepts for supplying heat from the thermal energy storage to the compressed gas are analysed.

The goal of the project is to increase the exergy efficiency of the integrated MES-TES-Expander system. To this end, mathematical modelling, model reduction, simulation, sensitivity analysis and experimental investigations on a dedicated test rig are combined. Model-based control strategies are developed, validated and optimized. The project aims to provide fundamental knowledge on the interaction between gas expansion, heat management and electrical power generation and thereby contribute to more efficient micro-CAES systems.

PRINCIPAL INVESTIGATOR

Prof. Dr.-Ing. habil. Dr. h.c. Oliver Sawodny
Institute for System Dynamics (ISYS), University of Stuttgart

RESEARCHER
Maja Raiser (ISYS)

PARTNERS
AGH University of Science and Technology, Kraków, Poland
Silesian University of Technology, Gliwice, Poland

FUNDING
National Science Centre Poland, OPUS 28, Lead Agency Procedure (LAP), with international cooperation involving the German Research Foundation (DFG)