Employing compressed air energy storage is an essential strategy to meet the boosted power demand at any hour of the day. During off-peak hours, the air is stored in storage and can be used in the combustion chamber later. A system’s energy efficiency is essential, and waste heat recovery sub-systems could increase this factor. The following study analyzed a waste heat recovery system of a Brayton cycle from the exergy and exergo-economic perspectives. The system includes three sub-systems. Dual-ORC and a PEM electrolyzer are employed to recover the waste heat during the charge and discharge phases of the compressed air energy storage (CAES). Additionally, the system performance was compared using two different ORC fluids. The system was modeled separately for the air storage’s charge and discharge phases using Engineering Equation Solver (EES) software. Optimal solutions for both phases are investigated by genetic algorithm (GA). The results revealed that within 24 h of system operation, 5.42 kg of hydrogen could be produced with a cost rate of 8.37 $/h in the charge and 6.18 $/h in the discharge phases. The highest exergy destruction rate occurred in the combustion chamber, with a value of 238.9 kW. The ORC turbines could produce 18.459 kW and 14.993 kW power in the charge and discharge phases. In addition, the round-trip efficiency (RTE) and exergetic round-trip efficiency (ERTE) for the system were 30.82% and 30.39%. The optimization revealed that optimal ORC turbine power production is 12.743 kW and 11.939 kW in the charge and discharge phases.
