What is Induced Draft Tower? | Working of Induced Draft Cooling Tower

A cooling tower is a heat sink that dissipates useless heat to the environment by cooling the flow of water to a low temperature. The cooling towers have two major types: mechanical draft cooling tower and natural draft cooling tower. The mechanical draft cooling towers are the most commonly used cooling tower than the natural draft cooling towers. An induced draft cooling tower is a most common type of mechanical cooling tower. This article mainly explains the various aspects of an induced draft cooling tower.

What is an Induced Draft Cooling Tower?

An inducted draft tower is a cooling tower that contains a various number of electric fans installed at the top of the tower. The fans of the tower blow air in the upward direction against the water flowing down around the wooden packing or planks. Because the water flow moves in the opposite direction of the airflow, the top warmer water makes contact with the moist air, and the bottom cooler water makes contact with the drier air. This method improves the heat transfer efficiency of the induced draft cooling tower.

These towers have round or square shapes. They use sprinklers or static manifolds for the water distribution process.

Working of Induced Draft Tower

An induced draft cooling tower has a spray distribution header, baffles, fans and drift eliminator. An induced draft cooling tower works in the following way:

  • First of all, the spray distribution header injects the entering cooling water all over the cooling tower.
  • The spray distribution header directs the spray water downward toward the deflector to maximize contact time between air and water.
  • A ‘Cooling water fill’ is used to achieve the maximum heat exchange surface. Metal, wood, PVC or other materials are used for the construction of ‘cooling water fill’. Air sucks into the cooling tower through well-designed “louvres”.
  • Large fans draw air into the baffle area, lower the water temperature and cool it. This tower also has a drift eliminator to prevent water droplets from becoming trapped in the exiting airflow.

Advantages of Induced Draft Cooling Tower

The induced draft cooling tower is more economical and efficient than other cooling towers. It has the following major advantages:

  • It has high flexibility
  • It is economical
  • These types of mechanical draft towers require low maintenance.
  • They have easy maintenance.
  • They have easy installation.
  • The induced draft tower has low noise than other mechanical towers.
  • They have the flexibility to any water flow.
  • They have the ability to deliver high thermal efficiency.
  • These towers deliver outstanding protection against the icing of the moving parts.
  • They have constant airflow irrespective of ambient air temperature
  • They are compatible with different materials such as steel, concrete, FRP and wood.

Forced Draft Cooling Tower Vs Induced Draft Cooling Tower

The main difference between forced draft and induced draft cooling towers is the installation location of the fans that suck air from the atmosphere.

The fan of the forced draft towers installs at the bottom and outside of the tower to allow air to circulate from the bottom to upward. However, the fan of the induced draft towers install at the top just above the eliminator, which allows the air to circulate from the head of the tower to the bottom.

Some of the advantages of using an inductive ventilation tower over a forced-air cooling tower are:

A sharp difference between the Forced draft tower and the Induced draft cooling tower is given below:

Induced Draft TowerForced Draft Tower
It has more efficiency than the forced draft tower.It has less efficiency.
This tower consumes low power (50%) than the forced draft tower.It consumes a high amount of energy which increases the utility bill cost.
The top of this tower installs at the top.The fan of this tower installs at the bottom.
The installation of a fan at the top of the tower generates low air pressure.The installation of a fan at the bottom of the tower generates high air pressure.
This design requires less motor power.It requires more motor power.
They use only axial pumps.They use both centrifugal and axial pumps.
The induced draft cooling tower requires low space for installation.The forced draft cooling tower requires large space for installation.
It has easy maintenance and installation.It has complex maintenance and installation.

Leave a Comment