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Air or water cooling? You decide

Published: 11 May 2018 - Rachael Morling

Steve Hughes, managing director of REO UK, explores how businesses can choose between air-cooling and water-cooling systems for industrial applications

Industrial equipment gets hot during use, damaging components and hindering functionality. This is particularly true of electrical equipment where, in addition to the typical operational temperature, there is also the heat generated by currents on the network. As a result, cooling systems are often installed in equipment.

However, cooling electrical infrastructure and industrial equipment isn’t as simple as just turning on a fan – even the location of the device needs to be considered to ensure the system is cooled effectively and safely.

There are two main ways of regulating device temperature. Air-cooling uses fan technology to circulate air around the device. Water-cooling uses liquid coolants to transfer heat out of equipment – and this is often met with apprehension by plant managers.

The pros and cons of each technology

When asked about cooling, many people initially think of a fan, but these are not without their limitations. For example, the inclusion of a fan often means that the enclosure of a device needs to be bulkier to accommodate it, which can cause problems with integrating devices into certain industrial setups.

This is especially true with electrical power controllers, as many are integrated into transformer cabinets. In instances such as this, the bulkier design of products featuring fans may cause problems and engineers may require the sleeker design of a water-cooled power controller.

However, air cooling is relatively inexpensive and typically requires less maintenance beyond the replacement of filters. In addition, fans are also able to provide effective heat transfer in more remote applications.

One of the biggest concerns plant managers have with alternative systems such as liquid coolants is their safety and stability. Many engineers have reservations about using water-based systems in close proximity to electrical equipment.


Initial safety concerns aside, water-cooling boasts a range of benefits that go beyond those offered by traditional air-based systems. In fact, these systems are able to deliver on the areas where fans often fall short.

Water-based systems operate on a very simple principle of heat exchange: pipes containing a liquid coolant circulate around an enclosure and out of the device to keep components cool. The excess heat generated during use is thermally conducted by the water in the pipes. This heated water is then transferred out of the device and into other industrial processes, such as plant heating.

The development of cooling technology in recent years means that it now poses no risk of causing an electrical fire. This is due to the self-contained housing that these systems include as standard, which ensures that no water can reach critical components in the unlikely event of a coolant leakage.

Despite this, the system remains compact so that it can be easily fitted into equipment without increasing the product footprint, meaning that water cooling can now be used in environments where space is limited.

The biggest selling point for water-cooling is its increased energy efficiency. Not only are fans limited by their reliance on ambient temperatures to cool down overheating components, but multiple fans might be necessary, which increases the energy consumption.

Conversely, water has a high heat conductivity so systems only require a single pump to effectively cool infrastructure. This coolant can also be stored in the pipes at a temperature below a plant’s ambient level for even faster cooling.

Engineers looking to specify liquid cooling need to consider the fact that, although it will have a higher return on investment, the initial setup of liquid cooled systems is more complex and more costly than air-cooled systems.

Making the decision

The first step to selecting the right cooling system is to identify where the device will be used and what the typical operating challenges will be. For example, businesses in the electroplating sector will find that a lot of the copper sulphate particulates produced during plant production can get into the enclosure vents of air-based systems and corrode core components and  wiring. In these situations liquid-cooled alternatives might be preferential.

Likewise, high voltage electrical infrastructure generates more heat than a standard electronic device. To this end, electrical OEMs such as REO UK can work with electrical engineers to determine the best solution for particular electrical requirements.

The REOTRON MDW 700 power controller, for example, is designed for  use with industrial transformers and is available in both air- and water-cooled versions. For transformers expected to operate at more than 50A, it is advisable that businesses opt for either additional fans for the air-cooled model or for the water-cooled REOTRON MDW 700 WK model to eliminate the risk of overheating.

The final step to choosing the right cooling system is to determine how regularly it will realistically be maintained. Fan filters need replacing frequently to avoid a build-up of contaminants that can lead to overheating, so using these systems in difficult-to-reach or less frequently maintained applications is not recommended.

Industry Connections: REO (UK) Ltd

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