Technology

Top Facts about Cooling Towers in Australia

A cooling tower refers to a device for heat rejection which expels heat to the atmosphere via cooling of a water stream to a reduced temperature. A cooling tower may use either evaporation of water to remove heat and cool the fluid or rely only on air to cool the working fluid.

A cooling tower refers to a device for heat rejection which expels heat to the atmosphere via cooling of a water stream to a reduced temperature. A cooling tower may use either evaporation of water to remove heat and cool the fluid or rely only on air to cool the working fluid.

The typical applications of cooling towers Australia are to cool circulating water in chemical and petrochemical plants, oil refineries, nuclear power stations, thermal power stations, and HVAC systems used to cool buildings. They vary in size from tiny rooftop units to huge hyperboloid structures.

Principle of Operation

The main principle of operation of a cooling tower is the cooling of warm water by means of evaporation. The water evaporates because of the hot water droplets coming in contact with air. Such evaporating water additionally absorbs the latent heat from the water surrounding it. Water is cooled by the loss of latent heat.

Types of Cooling Towers

As per the method adopted to circulate the air, cooling towers might be classified as:

  • Cooling towers with Natural draft
  • Cooling towers with Mechanical draft

Natural Draft Towers

As per the name, in this cooling tower, the air is circulated by natural convection. These are further classified into:

  • Spray Type:

The complete system is housed inside a box-shaped structure, which also features louvers, spray nozzles and spray headers. The Louvers (typically made of stainless steel) are located on the sides to improve natural circulation of air inside the cooling tower. For preventing water droplets from carrying over to the atmosphere, louvers are slanted towards the inside. Typically, such types of cooling towers are placed outside the building so that air can pass freely through the tower.

The spray header is situated on top, and warm water is fed into it by means of a pump. The spray nozzles spray the warm water inside the tower. Air reacts with warm water, causing water droplets to evaporate. The water that evaporates also captures latent heat from surrounding water, causing the cooling of the remaining water. Size of spray is crucial. A fine spray causes a great amount of water to be taken away by air. But this will be reduced by a big spray.

  • Splash Deck Type

It is similar to the Spray type. A water box is used instead of a spray header. Its bottom features small holes. Also, it features decking inside the tower. Hot water enters the water box and splashes via holes in the water box, upon the decking. The main aim of the decking is to enhance the surface area of air contact with warm water. This cooling tower is 20% to 30% more effective than a spray type.

  • Mechanical Draft Cooling Towers

These are similar to natural draft towers of cooling. In this, the air is circulated inside the tower mechanically in place of natural circulation. Centrifugal fans or propeller fans might be used.

What are the advantages of mechanical draft cooling towers?

  • Cooling towers with a mechanical draft (MD) are much smaller than cooling towers using natural draft (ND).
  • MD cooling towers enables control over capacity by controlling the speed of the fan.
  • ND cooling towers can be kept only in open spaces. MD cooling towers do not depend on the air in the atmosphere and so can be kept inside buildings.

These are all some top facts about cooling towers Australia.

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