Air-cooled and spraying spray water sprays into the surface of heat exchanger tube through spray pump, resulting in a very thin water film wrapped around the heat exchanger tube, heated by high temperature medium inside the heat exchanger tube, which promotes the evaporation of water film. Water evaporates from liquid to gaseous state, absorbs latent heat of vaporization, and absorbs tens of times more heat energy than medium in the same state. At the same time, due to the strong pumping force of the fan, evaporated water vapor is quickly taken away, low humidity air is filled in by the inlet grid, so the cycle is continuous; some water droplets taken by water vapor are recovered by the water collector, and the non-evaporated spray water falls back to the bottom of the catchment tank, pumped out by the spray pump, pumped into the upper spray pipeline, and reused.