In the last decades, increasing energy cost have caused a special attention to optimization of energy usage. So, many studies and researches have been carried out to improve and correct different industrial processes that use various type of energy. Power plants are one of the major units in the industry of any country. Therefore, it is an essential task to simulate these units and their different components in order to increase their performance and efficiency. In some power plants the dry cooling tower is used that is one of the most important components. Performance of dry cooling towers is strongly affected by wind flow and ambient temperature. Generally speaking, wind flow decrease performance of dry cooling tower that results in power plant output power and efficiency reduction. These negative effects can sometimes lowers total power plant power production capacity up to 40 percent. This energy loss imposes a big damage on power plant and this is the reason of why dry cooling towers must be studied. In this work, a commercial numerical code was used to simulate the fluid flow and heat transefer. Due to the turbulent nature of problem, the turbulence model is used. First, geometry of a dry cooling tower was constructed and a suitable grid was produced for it. Next, to ensure validity of geometry, grid, its boundary conditions and solution parameters, simulation of dry cooling tower in wind flow, that has been carried out befor by some researchers, was done and the results was compared with theirs. The agreement was acceptable. In this simulation, the performance of the tower in no wind condition as an ideal situation is studied and then the impact of different wind speeds have been investigated separately. Furthermore the effect of wind break as a solution to tackle the wind problem has been investigated.wind breaks situated radially in three position. It should be noted that wind breaks considered as a simple and plane walls. Results illustrate this fact that in windy condition, tower efficiency decreases significantly and this reduction has an almost direct relationship with wind speed. In reality wind destroy uniform distribution of static pressure around the tower and also create a pair of vortices in tower which disturbs natural suction of it. Generally using wind breaks with different position improve performance of cooling tower. Among mentioned positions, quad arrangement of wind breaks is more effective than dual arrangement in both low and high speed of wind. Keywords: Dry cooling tower, wind break, the effect of wind, power plant
