Cooler Thinking: How Free Cooling Can Improve Industrial Chiller Efficiency
08/09/2026 Atlas Copco Compressors UK
Energy efficiency has become an increasingly urgent priority for UK manufacturers, but the role of process cooling systems can sometimes be overlooked. In many industrial environments, chilled water plays a central role in product quality, process stability and operational continuity. Yet the way that cooling is generated can have a significant influence on energy use, running costs and equipment wear.
For sites that rely on industrial chillers throughout the year, the question is no longer simply whether the chiller is delivering the required cooling capacity. It is whether the system is doing so in the most efficient way for the application, the operating temperature and the local climate. That is where free cooling deserves closer attention.
Free cooling, sometimes referred to as ambient cooling or dry cooling, uses low outdoor air temperatures to help cool process water. When conditions are suitable, it can reduce the need for mechanical refrigeration. In some cases, it can allow the chiller compressors to be switched off completely for periods of operation. In others, it can share the load with the chiller, reducing the amount of work the compressor needs to carry out.
The principle is straightforward. A process generates heat, and that heat is carried away by water or a water-glycol mixture. In a conventional chiller-led system, the chiller’s refrigeration circuit removes that heat, with the operation of the compressor accounting for a significant proportion of the system’s electricity demand. With free cooling, the process water can be passed through a separate cooler or coil, where fans draw ambient air across the heat exchanger to remove heat before the water returns to the process.
When the outside air is cool enough, the system can operate in full free cooling mode, with the ambient air handling the cooling load. When the air is cooler than the process water temperature but not cold enough to do all the work, the system can operate in partial free cooling mode, reducing the load on the chiller. When outdoor temperatures rise beyond the useful operating range, the system reverts to mechanical cooling.
This makes free cooling particularly relevant in the UK, where cooler ambient conditions are present for much of the year. However, the opportunity depends heavily on the process water setpoint. A process running at 7 °C will need colder outside air before free cooling becomes useful. By comparison, a process running at 15 °C has a wider operating window; as the required ambient temperature does not need to be as low.
This point is important because free cooling is sometimes misunderstood as a solution only for very cold conditions. In reality, its usefulness is tied to the relationship between the required process water temperature and the outdoor air temperature. The higher the acceptable water temperature, the more hours there may be in which ambient air can assist or replace mechanical cooling.
For manufacturers, that makes the first step a practical assessment rather than a product decision. What water temperature does the process need? Is that temperature fixed, or has it simply become the accepted norm over time? Does the process run continuously, seasonally or in shifts? Is the site using mechanical cooling even when outdoor conditions could be doing part of the work?
These questions matter because the suitability of free cooling is application specific. In applications where process water temperatures are suitable, free cooling can reduce compressor run time, which in turn lowers electricity consumption. Because compressors are among the main power consumers in a chiller system, reducing their operation can have a meaningful impact on running costs.
There are also positive lifecycle considerations. Less compressor operation can mean reduced wear on key components, fewer operating hours and potentially lower maintenance demand over time. Free cooling is therefore not only an energy discussion. It also connects to equipment life, resilience and the way cooling assets are managed across the full lifecycle of the installation.
The potential applications are broad. Free cooling is relevant in plastics manufacturing, pharmaceutical production, laser cutting, hydraulics, general process cooling and other industrial environments where chilled water is required. It can be considered as part of a new chiller installation, but it can also be reviewed on existing sites where free cooling has not yet been installed. In some cases, there may also be a case for replacing an older free cooler with a more suitable or better integrated system.
The potential to retrofit is also worth considering. Manufacturers may assume that efficiency improvements require a complete replacement of the chiller plant, but this is not always the case. Where the existing system and process conditions allow, a standalone free cooler can be assessed as part of a wider upgrade. This can give sites a practical route to reducing energy use without necessarily waiting for a full chiller replacement cycle.
However, free cooling should not be treated as a simple bolt-on. The design needs to reflect the cooling load, process temperature, glycol percentage, site layout, available space, pipework, controls and the desired operating strategy. A poorly integrated system may fail to deliver the expected benefit, or it may add avoidable complexity to the cooling circuit.
Control is especially important. The transition between mechanical cooling, partial free cooling and full free cooling needs to be managed properly. The system should ideally respond automatically to changing ambient conditions and process demand, so that process cooling remains stable while compressor operation is reduced where possible. For production environments, efficiency must not come at the expense of process reliability.
This is where the engineering approach becomes critical. A correctly specified free cooling system starts with understanding the application, not simply selecting a unit. The cooling requirement, water temperatures and installation constraints all need to be assessed before the most appropriate configuration is chosen.
Atlas Copco’s process cooling team supports this approach by assessing the cooling application and identifying whether free cooling can be integrated effectively into a new or existing installation. Depending on the site, this may involve a standalone free cooler designed around the required load, process temperature and available space, working alongside a suitable chiller system.
It also reflects the reality of industrial sites. Two manufacturers may both use process cooling, but their operating temperatures, production schedules, space constraints and maintenance priorities can be very different. A plastics processor, a pharmaceutical site and a manufacturer may all have opportunities for free cooling, but the system design and business case will vary.
The strongest case for free cooling is therefore made through evidence from the individual site. A proper review can establish whether the process water temperature is suitable, how many operating hours may be available, what changes would be needed to pipework and controls, and whether the expected savings justify the investment. In some applications, the case may be strong. In others, the process temperature or operating profile may make the opportunity more limited.
That balanced view is important. Free cooling is not a universal answer for every cooling process. It will not remove the need for mechanical refrigeration in all conditions, and it will not deliver identical results on every site. But where the application is suitable, it can provide a practical way to reduce reliance on compressor-led cooling and make better use of the ambient conditions already available.
For UK manufacturers under pressure to improve efficiency, reduce operating costs and support carbon reduction goals, that makes free cooling worth revisiting. The technology itself is not new, but the reasons for giving it serious consideration are now even stronger.
For more information on Atlas Copco’s approach to free cooling, visit: https://www.atlascopco.com/en-uk/compressors/customer-offers/atlas-copco-free-cooling
Print this articleFor more information, please contact:
Atlas Copco Compressors UK
Technology House
Hemel Hempstead Industrial Estate
Maylands Avenue
Hemel Hempstead
Hertfordshire
HP2 7DF
Tel: +44 (0)1442 261201
Email: compressorsGB.web@atlascopco.com
Web: https://www.atlascopco.com/en-uk/compressors
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