In order to evaluate the potential of a desiccant based evaporative air conditioning system, a second law analysis of the systems was investigated. In this work, a wide range of working parameters that are regeneration temperature from 90 degrees C to 110 degrees C, volume flow rate from 2000 m(3) to 4000 m(3) and ambient air conditions which are relative humidity, ambient air temperature and wet-bulb temperature is carried out for performance calculation of the system. It is observed from results that the Carnot COP and the thermal COP of the system varies vice versa during the day. The highest value of Camot COP and the thermal COP is about 25 and 0.62, respectively. Also, the cooling capacity has significant effect on the second law efficiency. The importance of this study shows that the second law analysis can provide useful information with respect to the theoretical upper limit of the system performance, which cannot be obtained from the first law of thermodynamic analysis alone. (C) 2016 Elsevier Ltd. All rights reserved.