COMPRESSORS & COMPRESSED AIR
SMARTER SELECTION STARTS HERE
Louis Cottaz, Product Manager at Donaldson, advises users to look beyond core specifications in compressed air dryer selection criteria. He outlines the variables that should be considered to optimise system effectiveness
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ompressed air dryers deliver moisture- free air that supports process consistency and equipment longevity. However, the selection process is often narrow, focusing on a handful of sizing criteria while overlooking additional variables that also influence system performance, regulatory adherence, and long-term compressed air installation Total Cost of Ownership (TCO). Understanding the precise installation
environment of the compressed air dryer is crucial. Location impacts everything from air density and dryer capacity to corrosion protection needs. For example, the considerations for a roof installation compared to a ground installation are dramatically different due to environmental extremes and structural issues. Unique challenges related to roof installations include those related to thermal stress, weather exposure, accessibility, and freezing risks. The acoustic profile of a compressed air dryer is an often-overlooked environmental factor, yet some may generate noise levels that approach the threshold for hearing protection. Noise emissions are not uniform and vary
according to the unit’s underlying moisture removal technology. Desiccant dryers, required for achieving very low dew points, operate with a highly disruptive noise signature due to the purge air exhaust used. In contrast, refrigeration dryers present a more consistent but less intense noise problem. Sophisticated silencers included in dryers can help to address this issue.
Servicing factors to consider The ease and speed of maintenance are significant contributors to long-term operating costs and production reliability. As a compressed air dryer is an integral part of the manufacturing process, when it goes offline for servicing, the production line may be interrupted. A key question is not just if it can be serviced, but how fast and how easily it can be done. This includes considering whether filters can be replaced without extensive disassembly and essential components like cartridges can be swapped out easily. In many industrial facilities, dryers are often placed in tight, inconvenient spaces, or a compact design might mean that essential service points are pressed against a wall or obscured by
piping. If a unit requires significant disassembly or the use of specialised lifting gear just to access a component, the service time increases, which can lead to higher labour costs and greater risk of accidental damage. This is particularly relevant for outdoor installations, such as those on a roof, where accessibility is already a major logistical hurdle.
Not all compressed air dryers are built for the same timeline. Some are designed for a short economic lifespan, others for more than 20 years in critical environments. Materials coating systems, like those compliant with DIN EN ISO 12944, and component quality all factor into the expected lifespan of a compressed air dryer. One key consideration is that while investing in a longer lifespan might cost more upfront, it may potentially save significantly when it comes to TCO. In addition to robust construction, the system should also be designed for low pressure drop, as unnecessary restrictions force compressors to run at higher discharge pressures, increasing energy consumption and operating costs. However, oversizing components is not systematically beneficial. While larger equipment
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PROCESS & CONTROL ENGINEERING | MAY 2026
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