How a Cooling Tower Works
Cooling towers are equipment that dissipates waste heat generated in industrial processes or refrigeration and air conditioning systems by utilizing the contact between water and air through evaporation.
The basic principle is:
Dry (low enthalpy) air, after being drawn by the fan, enters the cooling tower through the air intake network; high-temperature water molecules with a large saturated steam partial pressure flow into the lower-pressure air. Wet (high enthalpy) water is sprinkled into the tower through the sprinkling system. When water droplets come into contact with the air, on the one hand, due to direct heat transfer between the air and the water, and on the other hand, due to the pressure difference between the water vapor surface and the air, evaporation occurs under the pressure, which carries away the latent heat of evaporation, removing heat from the water, thus achieving the purpose of cooling.
The operation process of the cooling tower:
The operation process of a circular counterflow cooling tower: Hot water is pumped from the machine room at a certain pressure through pipes, strainers, elbows, and a central strainer to the tower's sprinkling system. Water is evenly sprinkled onto the packing material through small holes in the sprinkling pipes; dry, low enthalpy air is drawn into the tower from the bottom air inlet by the fan; as the hot water flows over the packing material, a water film is formed for heat exchange with the air; the high humidity, high enthalpy hot air is extracted from the top; the cooled water drops into the basin and flows into the main unit through the outlet pipe. Generally, the air entering the tower is dry with a low wet bulb temperature, and there is a significant difference in the concentration of water molecules and kinetic pressure difference between the water and air. When the fan operates, under the action of static pressure within the tower, water molecules continuously evaporate into the air, becoming vapor molecules, which reduces the average kinetic energy of the remaining water molecules, thereby lowering the temperature of the circulating water. From the above analysis, it can be seen that the evaporation cooling is unrelated to whether the air temperature (commonly referred to as dry bulb temperature) is lower or higher than the water temperature, as long as water molecules can continuously evaporate into the air, the water temperature will decrease. However, the evaporation of water into the air does not continue indefinitely. When the air in contact with the water is unsaturated, water molecules continuously evaporate into the air, but when the air on the water-vapor contact surface reaches saturation, water molecules cannot evaporate further and are in a state of dynamic equilibrium. The number of water molecules evaporated equals the number of water molecules returning to the water from the air, and the water temperature remains constant. It can be concluded that the drier the air in contact with the water, the easier the evaporation process, and the more easily the water temperature can be lowered.
Cooling Tower Classification
One, classified by ventilation methods, there are natural ventilation cooling towers, mechanical ventilation cooling towers, and mixed ventilation cooling towers.
Section 2: Cooled towers are classified by the way hot water contacts with air, including wet cooling towers, dry cooling towers, and dry-wet cooling towers.
Three: There are counterflow cooling towers, crossflow (alternating) cooling towers, and mixed flow cooling towers, classified by the direction of hot water and air flow.
Four: General air conditioning cooling towers, industrial cooling towers, and high-temperature cooling towers.
Section 5: Cooling Towers Divided by Noise Levels - Standard Cooling Towers, Low-Noise Cooling Towers, Ultra-Low-Noise Cooling Towers, and Ultra-Silent Cooling Towers.
Cooling tower application range
Waste heat generated during industrial production or refrigeration processes is typically carried away using cooling water. The function of a cooling tower is to exchange heat between the cooling water carrying the waste heat and the air inside the tower, transferring the waste heat to the air and dissipating it into the atmosphere. For instance, in a power plant, the boiler heats water into high-pressure steam, which drives the turbine to generate electricity. After the turbine's work, the exhaust steam enters the condenser, where it exchanges heat with the cooling water and condenses into water, which is then pumped back to the boiler for recirculation. During this process, the waste heat from the exhaust steam is transferred to the cooling water, causing the water temperature to rise. The cooling water carrying the waste heat then transfers the heat to the air in the cooling tower, which is then released into the atmosphere through the exhaust duct. The cooling tower is widely used in various fields, including air conditioning cooling systems, refrigeration series, injection molding, leather production, foaming, power generation, steam turbines, aluminum profile processing, air compressors, and industrial water cooling. The most common applications are in air conditioning cooling, refrigeration, and plastic chemical industries.
