Energy and exergy analyses of direct ammonia solid oxide fuel cell integrated with gas turbine power cycle

This study presents the integration of direct ammonia solid oxide fuel cell with a gas turbine (DA-SOFC/GT) in a novel combined cooling, heating and power (CHCP) cycle. The integration strategy is compared for oxygen ion-conducting solid oxide fuel cells (SOFC-O) and hydrogen proton-conducting solid oxide fuel cells (SOFC-H). Unlike hybrid SOFC-absorption heat pumps, the current system is designed to exploit the refrigeration properties of ammonia to provide cooling with minimal bearing on complexity and capital cost. A system analysis is developed to cover both electrochemical and thermodynamic modelling. A detailed parametric study is also conducted to investigate the effects of varying the operating conditions and parameters on the energy and exergy efficiencies and the overall system performance. The results reveal that the SOFC-H integrated system offers better performance than that with the SOFC-O option. At an operating temperature of 1073 K and a pressure of 500 kPa, the respective energy and exergy efficiencies of the SOFC-H integrated cycle reach 81.1% and 74.3% compared to 76.7% and 69.9% for the SOFC-O. Under the same operating conditions, the cooling effectiveness of the system with both SOFC types becomes 14.7% based on the lower heating value (LHV) of ammonia.

► Integration of direct ammonia solid oxide fuel cell with a gas turbine.
► Combined cooling, heating and power cycle.
► O2 ion-conducting solid oxide fuel cells compared to proton-conducting solid oxide fuel cells.
► Energy and exergy efficiencies and the overall system performance.