Natural draft dry cooling tower (NDDCT) is susceptibly affected by ambient conditions, especially environmental temperature and natural wind. The performance should be improved during winter but faces a freezing risk. The traditional modifications to relieve the adverse influence of winter chills were mainly based on "try and error". In this study, concentrating on the potential of airside adjustments of louvers, a 3D numerical model of large-scale dry cooling system of the whole coal-fired power plant is established. The inherent mathematical relationships of heat transfer processes in each column of NDDCT and condenser of turbine are deduced in the view of entransy. A global optimal control of opening degrees of louvers of NDDCT under crosswinds during winter is proposed. Taking a practical 660 MW supercritical dry cooling power generating unit located in north China as object, the potential of releasing the freezing risk by airside adjustment of louvers is revealed under both natural wind and winter chill conditions. (C) 2019 Elsevier Ltd. All rights reserved.