The article presents the results of numerical simulation of the protection system of the mouth of the exhaust tower of a cooling tower with natural traction from freezing. To prevent the formation of ice, it is proposed to install an atmospheric air supply system at the mouth of the cooling tower, which ensures the creation of a protective boundary layer at the inner wall of the cooling tower and allows you to separate the warm moist air of the cooling tower from the cold walls. To test the possibility of using such a scheme, a numerical simulation of the process was performed using the k-SST turbulence model. The use of an additional air flow injection system makes it possible to increase the efficiency and reliability of a naturally aspirated cooling tower and a thermal power plant as a whole. Modeling of the cooling tower protection system from the formation of ice showed the possibility of using this scheme in all ranges of outdoor operating temperatures.