What is Cooling Tower ? How does it Works ?

"Industrial processes and machines generate such large amounts of heat that continuous dissipation is necessary for efficient operation. The heat must be to the environment. This is through a heat exchange process. That is the basis of the cooling tower technology."

Cooling towers were essentially created to eliminate excess warmth from water used in industrial operations and send it out into the surrounding biosphere.Cooling Towers work in much the same way although the amount of water involved that needs to be evaporated is much greater than what the human body produces. This means that extra components will be needed in order for the process to be carried out efficiently.

Warm water from industrial equipment, commercial ac system or any other heat source enters the tower and spreads evenly at the top. As the water flows down the tower, the equipment fill spreads it over a large area to increase the water-air contact, thus enhancing heat transfer via evaporation.

A large volume of air is constantly moving along the fill courtesy of large fans in the tower. As evaporation takes place, the water loses heat. It eventually enters the tower sump at the bottom. The cool water then goes back to cool the initial heat source and the cycle repeats. For the sake of system dilution, of portion of the system water goes to the drain through a bleed-off valve. The makeup line feeds the cooling tower with fresh water for replenishment.

Different Parts of Cooling Tower :-
  • Body: Body or outer surface of cooling tower is often made up from FRP (fiber reinforced plastic), which protects the internal parts of cooling tower.
  • Bleed Valve: It is used to control the concertation of minerals and salt.
  • Eliminator: It is not allowed to pass water. Eliminator is placed the at top of tower, from which only hot air can pass.
  • Float Valve: It is used to maintain level of water.
  • PVC Falling: It reduces the falling speed of hot water and it is similar to beehive.
  • Mesh: When the fan is ON, it uses atmosphere air which contains some unwanted dust particles. Mesh is used to stop these particles and do not allow to enter dust in to cooling tower.
  • Spray Nozzles and Header: These parts are used to increase the rate of evaporation by increasing surface area of water.

There are many types of cooling towers out there because there are so many various environments and situations that they need to perform in. We are going to cover a few of the common cooling tower types here:

Hyperbolic systems are well-built and require a minimal amount of resources.It is Commonly used in nuclear facilities, hyperbolic cooling towers work due to their stack/chimney style design. This design is used to take advantage of the times when the air outside of the tower is cooler than the air inside the tower which causes the warmer, heavily humid air inside the tower to rise and eventually leave through the top of the tower. The upward draft effect cools the water in the tower.

These towers are designed to cool water by sending air across water descending from the distribution basin horizontally. Once the water has descended to the flowing collection basin it has been adequately cooled. Counterflow towers tend to be more compact, but have a higher initial and operating costs because of the added power needed to force the air in opposition to the water flow.

In these type of towers air moves vertically against water descending water and sends the extracted heat out of the top of the tower. In this system, the in-flowing air travels in a vertical path over the splash fill as the water streams down from the reservoir above. Counterflow systems are usually smaller than their crossflow counterparts. They are also more compact and ergonomically efficient which is can offset some of the sting of the higher costs of construction and operation.

Induced draft cooling towers :
Induced draft or mechanical draft cooling towers use some type of mechanical pressure, like a fan system, to push air upward inside the tower. Induced draft systems can also force air into the tower with a blow-through or pull it out through a draw-through.

Passive draft cooling towers :
Passive or natural draft cooling towers combine the upward motion of warmed air with a steep chimney architecture to organically pull air throughout the tower. Although passive draft systems may have either a counter or crossflow transport design, hyperbolic towers are always passive draft.

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