Development of a sustainable energy system utilizing a new molten-salt based hybrid thermal energy storage and electrochemical energy conversion technique

In the present study, an integrated solar and wind based cogeneration system is developed for power and ammonia production. A new molten-salt based thermal energy storage and electrochemical energy conversion technique is utilized, which includes electrochemical ammonia synthesis, direct ammonia fuel cell, and thermal energy storage system. A transient energy and exergy analyses is performed on the developed system considering the hourly variations in wind velocities as well as solar intensities. The energy efficiency of the overall system on monthly average days varies between a minimum value of 29.4% and a maximum value of 38.7% across the year. In addition, the exergy efficiency of the developed system is found to vary between 30.2% and 39.8%. Furthermore, the daily ammonia production is found to reach peak value of 4292.3 kmol/day during the year. Moreover, the maximum discharge capacity of the molten salt-based direct ammonia fuel cell system attains a value of 31.8 MWh across the year. Several parametric studies are also performed to assess the effects of varying operating conditions on the performance of the developed system as well as subsystem units.