The wet air cooler can be divided into 3 kinds of surface evaporation type, humidification type and spray type according to the water spraying mode, and the following two kinds are mainly in petrochemical industry. The surface evaporation air cooler is a kind of air cooling device which uses the evaporation of the external membrane to strengthen the heat transfer and the light tube. Humidification type wet air cooler is only suitable for dry and hot areas with lower relative humidity than 50%, because the lower relative humidity of dry air, the more cooling after humidification, the more significant the cooling effect. The spray-type wet air cooler is a spray-like water directly on the finned tube bundle, which utilizes the latent heat exchange of water evaporation and the air being humidification and cooling to enhance the heat transfer. At the same time, the presence of water mist can make the inlet air temperature of air cooler close to the ambient wet bulb temperature, increase the average temperature difference of heat transfer, and the heat exchange coefficient under 3% spray quantity can be increased by 2 ~ 4 times times than dry air cooler.
In short, compared with the dry type air cooler, in the hot summer, when the ambient temperature is high, the application of wet air cooler is more advantageous. However, the wet air cooler in the tube fluid temperature of more than 70 ℃, it is very easy to scale, and the outside air resistance loss is larger, about dry air cooling about 1. 4 times times. The area of tube bundle cannot be too large, so the relative area of unit device is small and the price is relatively high.