Enhanced design of Stirling engines via multi-objective optimization: Effects of dead volumes, regenerator effectiveness, and operating parameters

The thermodynamic optimization of Stirling engines has gained increasing attention due to their potential for high-efficiency, clean energy conversion. This study develops a constraint-satisfied single- and multi-objective optimization framework to maximize engine efficiency and work output while minimizing internal irreversibilities. Unlike previous studies, which often overlooked essential design constraints or used unrealistic parameter ranges, the proposed approach incorporates internal irreversibilities, dead volume ratios, regenerator effectiveness, and operating parameters to ensure practical and feasible design solutions. The methodology combines thermodynamic modeling with parametric and sensitivity analyses to evaluate the effects of key design variables, including minimum and maximum cycle temperatures, expansion and compression volumes, total and component dead volumes, regenerator effectiveness, and working fluid pressure. Results show that optimizing these parameters leads to a thermal efficiency of 42.93%, net work output of 836.85 J, and an irreversibility parameter Rs of 0.69, representing improvements of up to 138.5%, 32%, and 3%, respectively, compared to previous studies. Maximizing expansion and compression volumes, minimizing dead volumes, and increasing regenerator effectiveness are the most effective strategies for performance enhancement. Multi-objective optimization confirms that a balanced design yields significant improvements across all performance metrics. The proposed framework provides both methodological innovation and practical design guidelines for high-performance, energy-efficient Stirling engines, offering reliable recommendations for real-world clean energy applications.