Modeling and multi-objective optimization of an ammonia-hydrogen synergy power system

Ammonia‑hydrogen fuel demonstrates broad application prospects and significant development potential as a zero‑carbon energy solution. The synergistic use of ammonia and hydrogen can complement their respective advantages, facilitating the decarbonization of power equipment. This study proposes an ammonia‑hydrogen synergy power system, where exhaust gas temperature and electric heating are coupled to promote ammonia decomposition for hydrogen production. To achieve engine exhaust waste heat and electric heat cooperative control, a coupled 1D engine and 0D ammonia decomposition unit (ADU) simulation model of the power system is developed. A high-precision BP-Kriging surrogate model is trained to predict system performance under varying operating parameters. To deeply explore the system's collaborative optimization potential, the NSGA-II algorithm is employed to obtain Pareto solutions for brake thermal efficiency (BTE), ADU temperature, and brake-specific fuel consumption (BSFC). Subsequently, the entropy weight method (EWM) combined with the technique for order preference by similarity to ideal solution (TOPSIS) is applied to select the optimal operating parameters from the solution set. Results indicate that, under global operating conditions, the system achieves a 3.63% increase in BTE, a 16.75% rise in ADU temperature, and a 10.14% reduction in BSFC. Under the WHTC transient cycle, the system exhibits a 3.02% improvement in BTE, a 13.84% enhancement in ADU temperature, and a 11.39% decrease in BSFC.