A comparative study is applied to evaluate four combined power producing systems based on low-temperature and high-temperature proton exchange membrane fuel cells (LT-PEMFC and HT-PEMFC) with equal power generation of 1056 kW. Single-stage organic Rankine cycle (SORC) and cascade two-stage ORC (CTORC) are employed to recover the waste heat from the fuel cells as well as exploiting the hydrogen boil-off gas for generating excess power, and feeding to the fuel cells. The performance of the proposed systems is compared to energy, exergy, and exergoeconomic viewpoints. Also, a parametric analysis is carried out to assess the effects on the thermodynamic and economic performance of the investigated systems by considering main parameters such as current density, fuel cell operating pressure and temperature, turbine inlet pressure, and expander lead. The results obtained from the parametric analysis reveal that with increasing the fuel cell operating temperature the overall exergy efficiencies for the proposed combined systems based on LT-PEMFC and HT-PEMFC decreases and increases, respectively. Also, the net output power and the total product unit cost of the considered systems are optimized at a specific value of BOG expander inlet pressure. The results indicate that albeit the highest values of energy and exergy efficiencies among the considered systems (61.42% and 63.20%) are related to LT-PEMFC/CTORC but the lowest total product unit cost of 33.75 $/GJ is related to HT-PEMFC/SORC.

一项比较研究用于评估基于低温和高温质子交换膜燃料电池（LT-PEMFC 和 HT-PEMFC）的四种联合发电系统，等功率为 1056 kW。采用单级有机朗肯循环 (SORC) 和级联两级 ORC (CTORC) 回收燃料电池的废热，并利用氢气蒸发气体产生多余功率，并供给燃料电池. 所提出系统的性能与能量、火用和火用经济观点进行了比较。此外，通过考虑电流密度、燃料电池工作压力和温度、涡轮入口压力和膨胀机导程等主要参数，进行参数分析以评估对所研究系统的热力学和经济性能的影响。从参数分析获得的结果表明，随着燃料电池工作温度的升高，基于 LT-PEMFC 和 HT-PEMFC 的拟议组合系统的整体火用效率分别降低和增加。此外，所考虑系统的净输出功率和总产品单位成本在 BOG 膨胀机入口压力的特定值下进行了优化。结果表明，尽管所考虑系统中能量和火用效率的最高值（61.42% 和 63.20%）与 LT-PEMFC/CTORC 有关，但 33.75 美元/GJ 的最低总产品单位成本与 HT-PEMFC 相关/SORC。