Thermo-Economic Analysis and Optimization of Adiabatic Compressed Air Energy Storage (A-CAES) System Coupled with a Kalina Cycle

An adiabatic compressed air energy storage system (A-CAES) can improve the energy storage potential, compared with conventional CAES systems, by capturing the heat generated during the charge stage. However, a challenge remains in the utilization step of the stored thermal energy due to the energy loss from the thermal energy storage vessel, which has hindered commercialization of A-CAES. To utilize the thermal energy produced by a compressor during the charge process efficiently, a novel system that couples A-CAES system with the Kalina cycle (KC) is designed to recover the loss of heat. In the new system, which is characterized by a higher and more stable power output, a Kalina cycle and the expander absorb the heat released from thermal energy storage units to generate electricity. Theoretical thermodynamic analysis shows that the novel combined system can achieve more efficient operation than a single A-CAES system. By examining the effects of key thermodynamic parameters on the exergy efficiency and overall capital cost, a Pareto frontier obtained shows the tradeoff between exergy efficiency and overall capital cost of the system, where 47.17 % and 1.455 k$ kW⁻¹ are determined as the optimum values for the two objectives from the optimum design solutions.