Types of Cooling Towers: A Complete Guide for Australian Facilities

Cooling towers are essential for industrial plants, large commercial buildings, and processing facilities. They provide a cost-effective and energy-efficient way to remove heat, but choosing the right type is where most facilities get stuck. The options vary significantly by build, heat-transfer method, and airflow design, and the wrong choice can lead to higher energy costs, increased maintenance, or underperformance.

Marley Flow Control is one of Australia's leading manufacturers, suppliers, and maintenance technicians of cooling towers. Australian-owned and operated, we help facilities across NSW, Victoria and Queensland find and maintain the right solution.

This guide covers the main types of cooling towers so you can go into that conversation informed.

What is a Cooling Tower?

A cooling tower is a specialised heat exchanger that allows water and air to combine to cool hot water. During this process, small amounts of water evaporate, lowering the temperature of the water circulating through the tower. The cooled water is then returned to the condenser or boiler to be used again.

How Do Cooling Towers Work?

Water enters from an inlet at the base of the tower and is pumped up into a header fitted with nozzles and sprinklers. Spraying the water increases its surface area, which is critical for effective evaporation.

The water then passes through a PVC fill media, which slows its flow. Fans at the top of the tower pull air upward from the bottom. With a large surface area, slow flow rate, and exposure to moving air, evaporation occurs, and the water cools. The cooled water collects at the bottom of the tower and is recirculated.

Types of Cooling Towers by Build

Package Type - Package type cooling towers are factory-assembled and made from durable, corrosion-resistant materials such as fibreglass-reinforced polyester. Compact enough to be transported by truck, they come in capacities up to around 1,500 tonnes per cell. They suit facilities with moderate heat rejection requirements, including hospitals, shopping centres, and office buildings.

Field Erected - Field erected cooling towers are significantly larger than package type units, shipped in components and assembled on site. Once built, they cannot be relocated. Their size means greater cooling capacity, and they can be constructed to custom specifications, making them the preferred choice for oil refineries, power stations, steel processing plants, and petroleum facilities.

Types of Cooling Towers by Heat Transfer Method

Dry Cooling Towers - Dry cooling towers transfer heat through a surface that separates hot water from ambient air, with no direct contact between the two. They suit facilities where water is scarce or where regulations prohibit visible plume. The trade-off is energy efficiency: dry towers consume more energy than wet alternatives.

Open Circuit Cooling Towers - Also known as wet cooling towers, open circuit towers are the most widely used type due to their cost-effectiveness and efficiency. They use the natural process of evaporation to cool water, with emissions limited to small heated water droplets known as drift. Suitable for a wide range of commercial and industrial applications.

Closed-Circuit Cooling Towers - Closed-circuit towers, also known as fluid cooling towers, circulate a water and glycol mixture through a closed coil inside the tower. Because the fluid never contacts outside air, it is protected from contamination. The result is a cleaner, lower-maintenance system suited to facilities where process fluid purity matters.

Types of Cooling Towers by Airflow Generation Method

Natural Draft Cooling Towers - Natural draft towers rely on the shape of the structure, typically a tall concrete chimney form, to create airflow without fans. Warm air rises naturally and exits through the top. These towers are typically found at large-scale facilities such as power plants and require no mechanical components to drive airflow.

Mechanical Draft Cooling Towers - Mechanical draft towers use propeller or centrifugal fans to move air through the system. Cool, dry air is pulled in from the sides and bottom, while warm air is expelled through the top. These towers are significantly more compact than natural draft units, can be installed indoors, and allow precise control over airflow and performance.

Crossflow Cooling Towers - Crossflow towers are designed so air flows horizontally across the tower while water falls vertically downward. This configuration requires higher air volumes due to limited air-to-water contact time, but offers practical advantages:

• Near-silent operation

• Low pumping head, reducing operational costs

• Straightforward maintenance access

Counterflow Cooling Towers In counterflow towers, hot water enters at the top while air is drawn in from the bottom and travels upward, counter to the direction of the falling water. Lateral pipes and spray nozzles distribute the water into a fill medium, and warm moist air is expelled from the top by the fan. The counterflow design maximises air-to-water contact, improving thermal efficiency.

Which Cooling Tower is Right for Your Facility?

The right cooling tower depends on your facility's heat load, available space, water access, regulatory environment, and budget. There is no universal answer, but working with an experienced supplier makes the decision straightforward.

Marley Flow Control has been helping Australian facilities choose, install, and maintain cooling towers since 2002. Contact our team today for a free quote and expert advice on the right solution for your needs.