TYPES OF COOLING TOWERS CLASS NOTES FOR ENGINEERING

TYPES OF COOLING TOWERS CLASS NOTES

FOR ENGINEERING 

Cooling towers cool the hot water from

the condenser for reuse. A cooling tower

reduces the cost of water used in

condenser. Use of water in the condenser

is for condensing refrigerant for medium

cooling plants. Cooling tower is a

 special type of heat exchanger. In this, hot

water and atmospheric air come in

direct physical contact. Air heats up

& water gets cooled. Thus, some amount

of water evaporates and goes

away with air. Water cooled

condensers require cooling towers. Thus,

power plants, chemical processing

industries and steel mills use cooling towers.

Types of Cooling Towers

 Relative flow of water and air classify cooling towers. These are cross flow, counter flow and hyperbolic types. These are also classified on how air enters drawn into it. These have natural, induced, forced & balanced drafts of air.

Cross flow cooling tower

Water falls down vertically downwards. Air is blown in a perpendicular direction to the flowing water.

Counter flow type

Water falls down and air goes up.

Hyperbolic

This type is due the shape of the cooling tower. It is like a natural draft type. It uses a fan. Its shape increases the flow of air. Cooling is obtainable with evaporative cooling. It finds use in nuclear and power plants. These are vertical thus compact. Its efficiency is extremely high.

(i) Natural draft cooling tower

Uses no blower.

(ii) Forced draft cooling tower

When a blower from below introduces air into the cooling tower.

(iii) Induced draft cooling tower

When a blower is placed at the top of the cooling tower & sucks air into it.

(iv) Balanced cooling tower

When uses both  induced and forced drafts.

Out of these cooling towers, natural and forced cooling towers are more common in refrigeration and air conditioning.

 Advantages of a cooling tower

(i) Significantly reduces the cost of water used in the condenser.

(ii) Compact

Normally mount it on the roof of a building. It is  in the vertical orientation.

Difference between Natural Draft and Forced Draft Cooling Towers

Sr. No.	Natural Draft Cooling Tower	Forced Draft Cooling Tower
1.	Natural air using free convection cools hot water of the condenser.	Air with a blower cools hot water of the condenser.
2.	It is widely open on sides.	It is less open on sides.
3.	It occupies more space.	It occupies less space and hence is compact.
4.	It is less efficient.	It is more efficient.
5.	It is cheap.	It is costly.
6.	Install it in the open space where natural air is available freely.	Install it at the roof of the building.
7.	Used for less refrigeration requirements.	Used for large refrigeration requirements.