Development and evaluation of a new hybrid ammonia fuel cell system with solar energy

Highlights: • A novel solar tower based power generation system is developed. • A hybrid thermal energy storage and ammonia fuel cell system is introduced. • The energy efficiency of the developed system varies between 5.3% and 37%. • The exergy efficiency of varies between 5.7% and 39%. -- Abstract: In this study, a novel hybrid thermal energy storage and ammonia fuel cell system is developed and investigated for a solar tower based power plant. An annual analysis of the developed system is performed by considering the monthly average days. Also, the actual power demands as well as the solar intensity changes are taken into account. Thermodynamic approaches of energy and exergy analyses are utilized for system analysis. The energetic efficiency of the proposed power plant varies between 5.3% and 37% while the exergy efficiency ranges between 5.7% and 39%, depending on the corresponding power demands as well as available solar energy. The system simulation results for each month are also described in terms of the specific exergies and enthalpies at the turbine inlets. Furthermore, energy efficiency of the direct ammonia fuel cell is evaluated to be 37% and the exergy efficiency is found to be 34% at the peak power density. At a temperature of 500 °C, a specific thermal energy storage capacity of 266 kJ kg⁻¹ is determined for the hybrid system.