In present work, thermal analysis of cooling tower has been done using conventional Merkel approach and by an elaborated method. The elaborated model is due to Pope, which considers variation of Lewis number and includes evaporation loss. The model is capable of calculating air temperature, humidity ratio, cooling tower water outlet temperature and evaporation loss. Available models analyze packing zone but often leave rain and spray zone unanalyzed. Present analysis includes these zones too. The model can be used to predict cooling tower outlet water temperature under varying ambient conditions for different inlet water temperatures.

Total airflow measurement in a natural draft-cooling tower is always a subject of difficulty and possibility of errors cannot be overruled, therefore a program has been written for performance prediction of a natural draft cooling tower which takes cooling tower geometrical parameters, water flow and ambient conditions as input and predicts outlet conditions.

Airflow inside the cooling towers especially in natural draft cooling towers is not uniform. A rigorous exercise was taken to ascertain this fact by measurement. The cooling towers designed with uniform water distribution tend to give poor performance. Therefore recent trend is to have non-uniform water distribution. A model is made for analysis of cooling towers with varying water and airflow. This model is capable of handling any profile for water distribution and any profile for air distribution. The model has been validated from available data for cooling tower with non-uniform water distribution. For validation addition has been made in the program to accommodate varying fill height too. Simulation results show that significant improvement can be obtained in natural draft cooling towers by having non-uniform water distribution.

Keywords- Cooling tower, Merkel Integral, Lewis number, Evaporation loss, water distribution, air distribution.