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 types 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. Dry cooling towers are one of the most important components of a power plant. Performance of dry cooling towers is strongly affected by wind flow and ambient temperature. Generally speaking, Wind flow and increasing ambient temperature decreases 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 transfer. 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 for ambient temperature of 15 o C, that has been carried out before by some researchers, was done and the results was compared with theirs. The agreement was acceptable. In the next step, the effect of ambient temperature on performance of dry cooling tower was studied. The results containing heat exchangers heat transfer and outlet water temperature distribution, show that increasing ambient temperature lowers heat transfer from heat exchangers and increase the water outlet temperature from them and finally reduces the performance of dry cooling tower. This amount of decrease in heat exchangers heat transfer and increase in their outlet water temperature is not equal for all heat exchangers of cooling tower and depends on location of heat exchangers around the tower. In this work, the effect of unequal water mass flow division between tower sectors and heat exchangers, as a solution to improve the performance of cooling tower in wind, was studied too. The results of this study show that if water mass flow can be distribute properly between tower sectors; it can improve performance of tower in wind. Also if water mass flow has been divided between tower sectors in a certain manner, only one water mass flow distribution between heat exchangers can optimize the performance of dry cooling tower in wind.
