Abstract: With a well-developed three-dimensional numerical model of the solar-enhanced indirect dry cooling tower（IDCT）,the effects of solar radiation on fluid flow and heat transfer of the tower and the varying mechanisms caused by the environmental crosswind were evaluated. The distributions of the air flow and temperature fields inside and outside the tower,as well as the varying trends of the air temperature and velocity at different altitudes inside the tower were exported and analyzed. The performance comparison was carried out between the traditional and solar-enhanced IDCTs. The results showe that the introduction of solar radiation helps to mitigate the adverse impact of crosswind on fluid flow and heat transfer of the IDCT,especially reducing the vortexes inside the tower and improving the air intake and heat dissipation capacity of the sideward and leeward heat exchangers of the tower. Under no crosswind and low crosswind speed conditions,the internal air velocity and temperature near the ground and the collector of the solar-enhanced IDCT are higher than those of the traditional IDCT. The internal air near the ground gets more affected by solar radiation and has a higher temperature rise,while the internal air temperature at the middle altitude between the ground and the collector is slightly lower than that inside the traditional IDCT. At high crosswind speed,internal air temperature inside the leeward region of the solar-enhanced IDCT decreases along the radial direction of the tower due to the great internal vortex. The ventilation and heat dissipation rates of the solarenhanced IDCT under crosswind are higher than those of the traditional IDCT with a maximum increase of 10.5% and 5.8%,respectively. Besides,compared with the traditional IDCT,cooling performance of the solar-enhanced IDCT is less sensitive to environmental crosswind.