Thermal Performance Analysis of Natural Draft Dry Cooling Towers Based on New Theoretical Method

In present study, the performance of a Heller-type natural draft dry cooling tower in the Fars Combined Cycle Power Plant is investigated under different environmental conditions (ambient temperature and wind velocity), based on a new theoretical method. The data collected from the control center of this power plant confirms the accuracy of the theoretical method; Therefore, a new mathematical model is created for predicting the performance of this cooling tower. This model is only applicable for wind velocities less than critical velocity, which is usually large and uncommon in operational conditions. Using this model for the described Heller cooling tower, it is shown that in high ambient temperatures, as the wind velocity increases, the heat transfer rate in the cooling tower decreases with a lower slope. The results of using the new theoretical method for calculating the performance of three aligned cooling towers in the power plant, along with the measured data, showed that when the wind direction is perpendicular to the towers, the efficiency of each tower is lower than the single tower in the same condition. When the wind is in line with the towers' direction, the efficiency of the rear towers will increase from the tower in the wind attack line.