The working process of the Cooling Tower
Take the working process of a circular counterflow cooling tower as an example: hot water from the main room through a water pump at a certain pressure through the pipeline, the throat, the throat, the central throat will press the circulating water into the watering system of the cooling tower, through the water pipe The upper hole spreads the water evenly on the packing; the dry low-value air enters the tower from the bottom into the wind net under the action of the fan, and the hot film flows through the surface of the packing to form a water film and air for heat exchange. The hot air with high humidity and high enthalpy value is taken out from the top, and the water is dripped into the bottom basin and flows into the host through the outlet pipe. Under normal circumstances, the air entering the tower is the air that dries the low-humidity temperature. There is obviously a difference in concentration of water molecules and a difference in kinetic energy between the water and the air. When the fan is running, under the action of static pressure in the tower, Water molecules continuously evaporate into the air, becoming water vapor molecules, and the average kinetic energy of the remaining water molecules is reduced, thereby lowering the temperature of the circulating water. It can be seen from the above analysis that the evaporative cooling and the temperature of the air (generally the dry bulb temperature) are not related to or higher than the water temperature, and as long as the water molecules can continuously evaporate into the air, the water temperature is lowered. However, the evaporation of water into the air does not continue indefinitely. When the air in contact with water is not saturated, the water molecules continuously evaporate into the air, but when the air on the contact surface of the water vapor reaches saturation, the water molecules cannot evaporate, but are in a state of dynamic equilibrium. The amount of water molecules that evaporate is equal to the amount of water molecules that return from the air to the water, and the water temperature remains the same. It can be seen that the drier the air in contact with water, the easier it is to evaporate and the lower the water temperature.