April 2020

Optimising a compressed air system’s performance is not just about the compressor unit. Where it is installed and how the associated infrastructure is designed also has an impact on a system’s energy efficiency, how quickly a business will see a return on its capital investment, and in some cases, even its ability to comply with environmental controls. Martin Chitty, business development manager at Mattei UK, explains how to choose a suitable site to install a compressor. B ack in the day, air compressors were placed well away from the production area, often in a separate building due to noise. Whilst modern compressors are much quieter and can be installed on the same premises, the need to maximise energy efficiency and space utilisation, together with changes in production processes and environmental controls mean that there are now a whole host of factors to consider. So, what exactly should managers bear in mind when deciding on where to put an air compressor? Particles and pollutants Many manufacturing environments are plagued by a high concentration of airborne, small sized particles that are a side effect of the actual manufacturing process itself. From cooking ingredients in a food processing environment, to oil mist which further attract other contaminants, they can adversely affect compressors even if equipped with high efficiency intake filters. These particles can block up vital parts of a compressor. Furthermore, the compression process also makes the impurities more concentrated, which can significantly reduce the quality of your compressed air. Rotary vane compressors cope better than screw compressors in many aggressive environments due to a greater tolerance to contamination by airborne particles. Nevertheless, it is still best practice to avoid locations with excessive airborne pollutants, such as loading and unloading areas. Adequate airflow Air compressors move a considerable amount of air during their operation. A poorly ventilated area would cause a compressor to run unnecessarily hot, resulting in reduced efficiency, more frequent service intervals and should be given as to whether or not internal heaters should be installed if there is only one compressor, with no other form of maintaining a minimum temperature. Where there are multiple compressors, some of the waste heat could be redirected back into the compressor house rather than being expelled to atmosphere. Cheap heat Up to 95% of a compressor’s kilowattage is discharged as heat. Typically, 80% of this waste heat is recoverable. So as a minimum, it’s worth using it for space heating. For this to be an effective strategy, the compressor should be located near to where the heat is required without being too far from where it needs to be discharged in the summer. Alternatively, waste heat from water-cooled compressors or those fitted with a heat exchanger can be used to provide hot water for the production process, heating or sanitary purposes. For example, a compressor can be located next to the factory’s boiler. Rather than using cold water as make-up water, it can be pre-heated using heat recovered from the compressor. One significant advantage is that hot water is needed year round. On the other hand, demand for space heating is seasonal which should be taken into account when calculating the value of this recoverable heat. Considerate cooling Whilst rotary vane compressors run significantly slower than screw compressors and produce less noise, it is still essential to ensure that any noise associated with the heat discharge process complies with local environmental controls. With this in mind, it is best practice to direct ducting used to expel heat away from Process, Controls & Plant Focus on: Compressed Air The right site: Where to install a compressor and associated infrastructure 24 | Plant & Works Engineering www.pwemag.co.uk April 2020 ultimately, shortening its life span. If the compressor needs to be housed in an enclosed area where the only way to get fresh air to the unit is to cut an opening in the wall, weather louvres should be considered to protect the compressor and the intake air from harsh weather. However, a larger intake will be required to compensate for the reduced surface area as a result of the louvres. Climate control In the winter during sub-zero temperatures, a compressor will not start if its oil temperature falls below the minimum threshold. So in addition to weather louvres, consideration Martin Chitty, business development manager at Mattei UK.