In the present study, the experimental investigation and performance evaluation of a newly developed direct type ammonia fuel cell stack are performed. A solid anion exchange membrane electrolyte is also utilized. The performances of a single-cell and a 5-cell stack are investigated through thermodynamic efficiencies. The open circuit voltages for a single cell and 5-cell stack are obtained as 280 +/- 8 mV and 1249 +/- 37.5 mV respectively. Furthermore, the peak power densities are found as 6.4 +/- 0.2 W m(-2) and 13.4 +/- 0.4W m(-2) for a single-cell and a 5-cell stack respectively. Moreover, the effects of varying humidifier temperatures on their efficiencies are studied, and hence increasing humidifier temperatures are found to provide higher efficiencies. Both energetic and exergetic efficiencies at the peak power density are determined to be 52.4 +/- 1.6% and 49.3 +/- 1.6% respectively under the ambient conditions considered. (C) 2019 Elsevier Ltd. All rights reserved.