Cooling towers are a staple of many industries that use heavy equipment and require cooling devices. In this article, we talk about cooling towers and how they work. We also discuss their various types and designs. Read on!
A cooling tower removes heat using water circulating inside the unit. The tower evaporates water and expels heat into the atmosphere while returning colder water into the unit. They’re usually found in power plants, mills, and other commercial facilities that use refrigeration systems.
Cooling towers are also commonly used in:
- Water-cooled AC systems in hospitals, hotels, government offices, commercial complexes, and residential areas
- Oxygen plants
- Electrical power plants
- Refrigeration plants
- Induction heating steel furnace
- Milk and dairy plants
- Hydraulic oil coolers
- Biogas plant and renewable power plants
- Injection molding machines
Cooling towers are in demand in the following industries:
- Steel manufacturing and metal casting
- Oil refinery and manufacturing
- Car and vehicle manufacturing
- Food and food processing
- Solar power plants
- Chemical and petrochemical industries
Overheated flows through the tower, which recirculates and exposes it to cool dry air. Through the process of evaporation, heat leaves the recirculated water. The colder water then re-enters the equipment or process to cool the equipment down. Then, the cycle repeats.
Cooling towers have varying types and designs based on the way they cool water. As such, consider your industry and usage before equipping your structure with a cooling tower or buying cooling tower replacement parts.
There are two main types of cooling towers:
Natural draft cooling towers depend on natural convection to circulate and cool water. They mainly follow the physics of cold and warm air — that warm, moist air goes up, and dry, cooler air goes down. This then creates constant airflow.
As their name suggests, mechanical draft cooling towers use mechanical methods of circulating air inside the tower. They mainly use propellers and centrifugal fans to do this.
Mechanical draft cooling towers can be placed inside a building. It’s more advantageous than natural draft cooling towers since you can regulate the airflow inside the tower. On the other hand, they’re more expensive than their natural counterparts.
Cooling towers can also vary based on their circuit design. They can have open (direct) or closed (indirect) circuits.
A cooling tower with an open circuit design distributes warm water into a fill. The fill then provides an increased surface area for the air-water contact. As a result, a greater amount of evaporation takes place.
After evaporation, the cold water is collected into a basin. It then returns to the condenser to repeat the process all over again. The tower expels the heated air into the atmosphere.
In a closed circuit cooling tower, the air and water have no direct contact. The tower has two fluid circuits — one brings in the warm water, while the other is a tube bundle. Water passes through the tube bundle while a fan blows air over the tubes to cool the water. This process then facilitates heat exchange.
Cooling towers may also be categorized into the following:
- Crossflow: air flow horizontally while water flows vertically. This system doesn’t require air to pass through a distribution system.
- Counterflow: this ower uses a pressurized pipe spray system that pushes air upward and water downward
- Hyperbolic: this tower uses a chimney stacking approach that lets cool outside air push damp, warm air inside. Water is sprayed over the splash fill at the bottom of the tower. Then, an upward flowing air cools the water.