Performance assessment of two compressed and liquid carbon dioxide energy storage systems: Thermodynamic, exergoeconomic analysis and multi-objective optimization

Nowadays, large-scale energy storage systems (EES) are a crucial mechanism to realize large-scale grid-connected power generation from renewable energy. And the development of co-generation systems coupled with EES has encouraging economic potential. In this paper, two compressed and liquid carbon dioxide energy storage systems without extra heat/cold sources are proposed (denoted as LCES-E and LCES-EC). The system's principles are presented; the thermodynamic and exergoeconomic analyses models are developed; the effects of five primary parameters are obtained by parametric analysis; meanwhile, the potential of the systems is revealed by multi-objective optimization. The results show that both systems can provide stable electricity and cold simultaneously. The better cooling capacity makes LCES-EC superior, with the RTE, EVR and c_ptot reaching 78.66%, 12.69 kWh/m³ and 41.23 $/GJ. The compressor and turbine exergy destruction and cost exceed 55% of all components, and appropriately high levels of η_C and η_T are preferred for both efficiency and economy. The LCES-EC system guarantees both electrical efficiency and cold capacity, showing preferable features over previously reported systems.