Cooling towers are widely used by many industries to deal with excess heat that is produced by manufacturing processes and other industrial activities. Put simply, a cooling tower is a device that works to lower the temperature of a water stream. This is done so that the hot water in circulation is cooled enough to be used again in the boiler. Most cooling towers rely on using evaporation to lower the temperature of the circulating water.
Since 2002, Marley Flow Control has been a proud industry leader in cooling tower manufacturing. An Australian-owned and operated brand, we offer a high level of expertise and an extensive range of ready to order products. Our wealth of knowledge has allowed us to work with some of the country’s largest businesses that we are pleased to call our clients.
As industry leaders, we have a high level of expertise and can provide a wide range of cooling tower services. If you need help with your cooling tower, contact our highly experienced team to discuss your options today.
Cooling towers can differ significantly based on size, build, materials used and mechanisms of operation. Understanding the differences between various cooling tower types is essential for choosing the right one for your needs.
Below we answer some important questions you might wish to ask before deciding which cooling tower would be best for you.
How is airflow generated in cooling towers?
Cooling towers operate by using constant and reliable airflow which can be produced and maintained in a variety of ways.
A cooling tower can operate using:
- Natural draft. Such cooling towers are constructed in ways that utilise the design of the tower to move the air up by using fans.
- Mechanical draft. These rely on a centrifugal fan or propeller pulling the air from the bottom. The fan is usually placed at the top of the tower and blows warm air out of the tower while also sucking in the cool and dry outside air.
Natural draft cooling towers – best uses
Cooling towers that use natural airflow are usually located outside, which allows them to release warm air directly into the environment. This is why these are normally used in industrial settings – such as power plants located near the load centres and away from the fuel source point. In such cases, using a natural draft cooling tower allows saving on the costs of power that would otherwise be needed to operate cooling fans.
Mechanical draft cooling towers – best uses
These cooling towers tend to be significantly smaller than natural draft towers, which makes them suitable for use inside the plants and other facilities. As you are also able to monitor and control the speed of the cooling fans, mechanical draft towers are preferred where capability control is important.
Also, as these towers use power to operate the cooling fans, they are widely used where cheaper power is accessible – for example, at power plants located close to the fuel source.
Climate conditions also need to be taken into consideration, as natural draft towers are not well suited for areas with long, hot, dry summers. In such cases, the air density difference that is needed for an efficient operation of natural draft towers is hard to achieve, so mechanical draft towers are preferred.
How is heat transferred in cooling towers?
Cooling towers can use dry heat or wet heat transfer methods.
Dry cooling towers – best uses
A dry cooling tower simply transfers heat through a surface separating hot water from the air. As no water evaporation occurs, no additional water is needed. Hot water from the condenser just keeps circulating through the tubes exposed to ambient air that absorbs its heat, cooling it down. Sometimes, fans are installed to improve the airflow.
As this type of heat transfer is quite inefficient and involves high energy usage, it is reserved for situations where water supply is limited – or where regulations specifically disallow any plume.
Wet cooling towers – best uses
Also known as open circuit cooling towers, these towers use the natural process of water evaporation as a cooling method. What is emitted as a result is just heated water droplets that cause no harm to the environment.
Wet cooling towers are very popular because of their cost-efficiency and use of renewable resources (water). They are most likely to be your first choice if you have access to an adequate water supply.
How are cooling towers constructed?
Depending on your needs, you can have your cooling tower field erected – or you may decide to go for a package type tower.
Field erected cooling towers – best uses
These are large non-transportable towers that weigh over 1,500 tonnes per cell and have a significant cooling capacity. Because of their size, they need to be assembled on site. These towers are also often built to custom specifications.
Power plants, oil refineries, petroleum sites and steel processing plants often use field erected cooling towers.
Package type cooling towers – best uses
These towers are smaller in size than field erected towers – so they are assembled at a factory and then can be easily transported to the usage site.
Facilities with comparatively low heat rejection requirements – such as office buildings, hospitals and shopping centres – normally use cooling towers of this type.
We can design, build, inspect and repair your cooling tower
Marley Flow Control offers a comprehensive range of cooling tower design, installation, inspection and repair services. We can repair both the fill and mechanical components of a cooling tower and offer an ongoing full functional annual assessment of your tower. We also provide comparisons between a comprehensive refurbishment or a new cooling tower.
Our team of highly experienced technicians has the skills and equipment to fit new motors, driveshafts, gearboxes and fans in the field, including long laser alignments of up to four metres.
Find out how we can use our engineering experience to help find the right solution for your business needs. Contact us here for a free quote.