Thermodynamic analysis of integrated ammonia fuel cells system for maritime application

Abstract

This paper presents a novel multigeneration system that utilizes ammonia as the primary fuel for marine vessel applications. The system integrates and thermodynamically investigates various components, including solid oxide fuel cells (SOFC), gas turbines (GT), proton exchange membrane fuel cells (PEMFC), organic Rankine cycle (ORC), steam Rankine cycle (SRC), Kalina cycle (KC), and waste heat boiler (WHB). The primary objective of the integration strategy is to recover waste heat from the SOFC and harness the power generated by the PEMFC, resulting in improved thermal efficiency, reduced vessel startup time, and enhanced environmental sustainability. Mathematical models have been developed to facilitate the examination of the system’s thermodynamic performance. Comprehensive thermodynamic modeling employing energy and exergy analysis methods is employed to evaluate the effectiveness of both the proposed system and its subsystem. Moreover, the exergy destruction of all system components and integrated subsystems is quantified to provide a comprehensive understanding of their impact. The projected system exhibits an energy efficiency of 60.69% and an exergy efficiency of 57.50%. The waste heat recovery combined systems generate 1634.46 kW, accounting for 30.07% of the total power output of the integrated SOFC system. The performance of the system was analyzed through parametric studies, where different values of current density, distribution ratio (β) (from 0.1–0.4), and δ parameter (from 0–0.5) were examined. The findings revealed that increasing the current density led to a decrease in energy and exergy efficiency, despite an overall rise in the power output of the cogeneration system. Moreover, the waste heat boiler is capable of providing 1081 kg/h of superheated steam at 162 °C and 405 kPa to fulfill the heating requirements of marine lubricating oil, devices, and accommodation for seafarers on board the ship.