1. Internal Training Module
Cooling Tower Types
Welcome to HydroChem’s internal training module Cooling Tower Types.

2. Scope of Session
This training session is to provide an introduction to identifying Cooling Towers
This training session is to provide an introduction to identifying the different types of cooling towers.
We tend to talk about manufactures and brands which has some relevance although technically we need to also identify the configuration or type.

3. Induced Draft Counter Flow
The induced draft counter flow cooling tower is common. It can be identified by the fan at the top of the tower. The fan pulls air up through the tower in the opposite direction to which the water is falling. Usually air enters the tower through inlet louvres which also act as splash guards. Water is usually fed from the top by fixed or in the case of bottle type towers through rotating spray arms. Drift eliminators are installed to prevent loss of water through drift are usually found above the sprays.
Induced draft towers have the fan located in the hot, moist air stream on the exit face of the tower, drawing air upwards through the tower. This does place the fans and fan motors in a more corrosive environment than a forced draft cooling tower.
Round bottle type cooling towers have presented a problem for tower manufactures providing and fitting effective drift eliminators that meet drift loss limits. The Australian Standard AS sets a design standard for cooling tower drift of 0.002% based upon the circulation rate.

4. Induced Draft Counter Flow
These are all examples of induced draft counter flow cooling towers.

5. Induced Draft Counter Flow
Examples of bottle type induced draft counter flow cooling towers. Internal showing rotary head, water distribution arms above the fill pack and the drift eliminators atop.

6. Induced Draft Cross Flow
The induced draft cross flow cooling tower fan is also mounted on the top. With this type of tower the fan draws the air across the water falling from the top of the tower to the basin. Splash guards can extend from the fill down to the basin and the drift eliminators are to prevent drift out of the fill into air space below the fan. Towers may have sprays, nozzles or trays to distribute the circulating water over the fill pack. The distribution trays these days are normally covered to block out sunlight. You may still see uncovered trays which require inspection every visit as this area is prone to algae growth.

7. Induced Draft Cross Flow
Draft eliminator
Internal access walkway
These are a few examples of induced draft cross flow cooling towers which are common on larger buildings and industrial complexes. Construction materials vary from fiberglass, plastics, galvanised steel, timber and cement sheet. Most these days incorporate plastic fill packs as sheet or cubes which are said not to foul or clog although this is not always the case.

8. Forced Draft Counter Flow
The forced draft counter flow cooling tower has the fan located at the air inlet just above the tower basin. Air is forced vertically through the tower fill in the opposite direction to the water flow and out through the top of the tower. There are no splash guards and the drift eliminators are on the top of the tower.

9. Forced Draft Counter Flow
Air inlet fans
Although these towers look different they are forced draft counter flow cooling towers.

10. Forced Draft Cross Flow
The forced draft cross flow cooling tower has the fan mounted on one side pushing the air in a cross flow manner through the fill past the falling water. Eliminators are normally close to the air off side of the fill with splash guards protecting the air leaving the tower. Older cooling towers may only rely on the fill to reduce drift and splash. These cooling towers are far less common although the fans and fan motors on a forced draft cooling tower are not subjected to the harsh environment encountered in an induced draft cooling tower. Forced draft towers have the fan located in the cool, dry, ambient air stream on the entrance face of the tower, pushing air through the tower.

11. Forced Draft Cross Flow
As you can see there are few examples of these cooling towers around and a reward for a decent photo depicting the air on and off sides.

12. Evaporative Condenser Induced Draft Counter Flow
The evaporative condenser shown although an induced draft counter flow cooling tower defers is that the circulating cooling water does not leave the tower for remote cooling. The heat requiring removal is delivered to the cooling tower. Most of these towers are removing heat or cooling refrigerant contained in a coil that in turn is cooling plant.
We also see towers that are similar that are removing heat or cooling a similar coil or tube bundle that contains a secondary water circuit in a closed condenser loop. These cooling towers are referred to an fluid or industrial coolers.
In the preceding cooling tower variations types the towers were cooling water that was returning from a heat exchanger. The towers would be part of a system that was removing heat from an air conditioning plant, industrial process or mechanical plant.

13. Evaporative Condenser Induced Draft Counter Flow
Evaporative Condenser with refrigeration piping
Tube bundles
Galvanised steel
And Copper
Both examples are induced draft counter flow cooling towers with tube bundles sprayed with the circulating water drawn from the basin below. The difference is that the Evaporative Condenser is removing heat or cooling refrigerant and the Fluid Cooler cooling a secondary closed loop water circuit pumped through the tube bundle.
Fluid Coolers with closed water loop connections

14. Hyperboloid Cooling Towers Natural Convection Counter Flow
These cooling towers are normally associated with power station cooling with litre volumes in the tens of millions. In the Victorian LaTrobe Valley Loy Yang A coal fired power station tower has four cooling systems that hold around twenty million litres each, run two to three cycles and yes they require chemical treatment. Considerable draft is created through natural convection with the heat raising up the tower.

15. Conclusion of Internal Training Module
Cooling Tower Types
We hope that you have gained a further insight into cooling towers and thank for your attention.
If you have any suggestions for this or other presentations please provide feedback.