Multi-objective optimization for reciprocating expansion engine used in compressed air energy storage (CAES) systems

Instability poses a significant challenge for renewable energies such as solar and wind power. Addressing this issue involves generating compressed air and implementing storage solutions (CAES). Reciprocating engines emerge as a viable option for the recovery of compressed air, offering a potential solution to mitigate the instability associated with solar and wind energy sources. The current research initially identified the parameters influencing engine performance. Subsequently, the engine's performance was assessed at input pressures of 10, 8, and 6 bar. The optimization process was then carried out using the Pareto solution as a multi-objective optimization method, complemented by the TOPSIS method. These parameters included the engine speed, pis-ton diameter, piston stroke, inlet port diameter, and outlet port diameter. The results show the optimum engine speed at 6 & 10 bar is 1500 rpm and at 8 bar was 1750 rpm. Also, piston diameter at 6, 8 and 10 bar are obtained 12, 10 and 10 cm, respectively. Furthermore, the power generation at input pressures of 6, 8, and 10 bar was determined to be 15.86 kW, 14.02 kW, and 16.01 kW, respectively.