Heat recovery and thermodynamic cycle integration are promising options for integrated energy systems. In this paper, a hybrid system was designed and analyzed that integrates the waste heat recovery Kalina cycle (WHRKC) with the organic Rankine cycle (ORC) and hydrogen production via electrolyzers (WHR-KC-ORC-H2). The system is driven by engine exhaust gases at 519 K, and heat is recovered in a cascaded manner: the Kalina cycle utilizes the high-temperature portion of the waste heat, while the ORC recovers the lower-temperature waste heat from the Kalina cycle, maximizing overall energy utilization. The system was examined using comparative analysis and multi-objective optimization (MOO), with emphasis on the effects of work output, exergy efficiency, total exergy destruction rate, and total cost rate on performance. A genetic algorithm (GA) was employed to explore the coupled effects of key decision parameters on both economic and thermodynamic performance. The outcomes reveal that the GA successfully improves net total cost rate and energy efficiency. Several optimal configurations were identified, among which “S-point” was selected as the most balanced solution, achieving a cost of 36.15 $/h, an energy efficiency of 13.10 %, and an exergy destruction of 3136.16 kW. The cascaded waste heat recovery approach demonstrates a viable pathway for converting low-grade waste heat into both electricity and hydrogen, achieving a significant exergy efficiency (26.01 %) while maintaining economic feasibility. MOO proves to be a vital tool in the design of advanced cycles and provides a roadmap for future advances in sustainable and cost-effective energy production.
