A new solar energy system for ammonia production and utilization in fuel cells

Abstract

Ammonia is considered to be a promising energy storage medium that can address the challenges associated with hydrogen. It is essential to investigate the usage of ammonia for energy storage, especially for the applications of intermittent energy resources. Hence, in the present study, a new integrated solar-based ammonia synthesis and fuel cell system is presented. The excess power generated by a solar photovoltaic system is utilized to synthesize ammonia. Furthermore, a direct ammonia fuel cell is employed for electricity production when low solar energy is available. The system is simulated dynamically on the average day of each month and the performance is investigated through thermodynamic energy and exergy tools. The overall exergy efficiency lies in the range of 16.44%-16.67% while the overall energy efficiency during the year varies between 15.68% and 15.83%, respectively. Also, the discharge time capacity is found to vary between 2.6 and 8.3 h. Moreover, the ammonia synthesis rate reaches a peak value of 64.8 mol s−1 during high solar energy availability. In addition, the maximum energy discharge capacity of the system is evaluated to be 7924.2 kWh. Several parametric studies are also conducted, and the performances are studied comprehensively through energy and exergy efficiencies under various conditions. The developed system entails the advantages of high energy density as well as longer storage times as compared to other energy storage methods.