Introduction to how cooling towers work

A cooling tower is a device that utilizes the contact of water and air to dissipate waste heat generated in an industrial or refrigeration air conditioner by evaporation.

The basic principle is: after drying the air with low enthalpy value, it enters the cooling tower from the air inlet net after the convection of the fan; the high temperature water molecules with large pressure of saturated steam flow to the air with low pressure, and the water with high humidity and high value The water system is spilled into the tower. When the water droplets come into contact with the air, on the one hand, due to the direct heat transfer between the air and the water, on the other hand, due to the pressure difference between the surface of the water vapor and the air, evaporation occurs under the action of the pressure, and the latent heat of evaporation is brought to the present. The heat in the water is taken away to evaporate and heat transfer, thereby achieving the purpose of cooling.

The working process of the cooling tower: the working process of the circular counterflow cooling tower is as an example: the hot water is pumped from the main room through the water pump to the watering system of the cooling tower through the pipeline, the throat, the throat and the central throat with a certain pressure. Inside, the water is evenly spread on the packing through small holes in the water pipe; the dry low-value air enters the tower from the bottom into the wind net under the action of the fan, and the water film is formed when the hot water flows through the surface of the packing. The air is exchanged with the air, and the hot air with high humidity and high enthalpy is extracted from the top, and the cooling 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.