Effect of operation conditions on the second law analysis of a desiccant cooling system

•The second law analysis of the desiccant cooling system is evaluated.•Effect of various operating parameters on the system performance was studied.•Effect of ambient air temperature and relative humidity was investigated.•The Carnot COP is between 9 and 25. 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°C to 110°C, volume flow rate from 2000m3 to 4000m3 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 Carnot 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.