How a Cooling Tower Works

Cooling towers are equipment that dissipate waste heat generated in industrial processes or refrigeration/air conditioning systems by utilizing the contact between water and air, through the process of evaporation.

The basic principle is:

Dry (low enthalpy) air, after being drawn by the fan, enters the cooling tower through the air intake mesh; high-temperature water molecules with a high saturated steam partial pressure flow towards the lower-pressure air. The wet (high enthalpy) water is sprinkled into the tower through the sprinkling system. When water droplets come into contact with the air, both due to direct heat transfer between the air and the droplets and due to the pressure difference between the water vapor surface and the air, evaporation occurs under the pressure, which is the latent heat of evaporation. This process carries away the heat from the water, achieving the goal of cooling.

Cooling tower operation process:

The operation process of a circular counterflow cooling tower, for example: Hot water from the machine room is pumped through pipes, horizontal and curved pipes, and a central pipe at a certain pressure to the water distribution system of the cooling tower. Water is evenly sprinkled over the packing material through small holes in the distribution pipes. Dry, low enthalpy air, driven by the fan, enters the tower through the bottom air inlet. As the hot water flows over the packing material, it forms a water film and exchanges heat with the air, resulting in a high humidity, high enthalpy breeze being extracted from the top. The cooled water drops into the basin at the bottom and then 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 between the water and air. When the fan is operating, under the action of the static pressure within the tower, water molecules continuously evaporate into the air, becoming vapor molecules, which lowers the average kinetic energy of the remaining water molecules, thereby reducing the temperature of the circulating water. From the above analysis, it is evident that evaporation cooling is unrelated to whether the air temperature (commonly referred to as the dry bulb temperature) is below or above 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, the 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, maintaining a constant water temperature. Therefore, the drier the air in contact with the water, the easier evaporation occurs, and the water temperature is more easily reduced.

Cooling Tower Categories

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 categorized by the contact method between hot water and air, including wet-cooled towers, dry-cooled towers, and hybrid dry-wet cooled towers.

Three: There are counterflow cooling towers, crossflow (cross-current) cooling towers, and mixed flow cooling towers, categorized by the direction of hot water and air flow.

Four, Cooling towers are generally categorized by application into: General Air Conditioning Cooling Towers, Industrial Cooling Towers, and High-Temperature Cooling Towers.

Five, classified by noise level into standard cooling towers, low-noise cooling towers, ultra-low-noise cooling towers, and ultra-quiet 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 facilitate heat exchange between the cooling water carrying the waste heat and the air within 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 reuse. 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 exhausted into the atmosphere through the wind tunnel. The cooling tower is mainly used in air conditioning cooling systems, refrigeration series, injection molding, leather production, foaming, power generation, steam turbines, aluminum profile processing, air compressors, and industrial water cooling, with extensive applications in air conditioning cooling, refrigeration, and plastic chemical industries.