Compressors: Q&A with Andy Jones of Mattei

Process Engineering will include a feature on Compressors and related equipment in the July/August issue of the magazine. For this, we are asking major players in the sector to identify current trends in this area of technology and, in particular, their views on how effectively UK process companies are using compressors and related systems at present. The following comments from Andy Jones,general manager of Mattei, set the tone for the feature:

Q: How effectively/efficiently do you think UK process companies use compressors and related systems at present?

AJ: It varies from company to company, but in our experience not that many businesses understand how much it costs to run a compressed air system or the factors that affect this. An example is using a pressure setting that is higher than needed (just a one bar reduction in pressure will reduce energy consumption by approximately seven per cent).

Meanwhile some businesses are using a higher air quality than is actually needed, which again adds cost to compressed air production. In recent years we have seen an increase in demand for ‘oil-free’ compressors to produce ‘oil-free’ compressed air. Although there is often a legitimate reason for this request, before investing in costly equipment we would urge the purchaser to thoroughly assess the actual purity of air required and specify it using ISO 8573-1:2010 to see if ‘oil-free’ air is needed. And, if it is, to assess if class one rather than class zero would be sufficient.

The more stringent the purity, the higher the cost is to achieve it - so it’s important to consider whether or not the entire system requires the highest purity or just a particular area, which could then be served by point of use air treatment or a dedicated smaller compressor.

Furthermore, we often see systems that have had sections added or removed without any thought for checking whether it is still running efficiently. We recently changed a 75kW compressor for a 45kW compressor at one company without reducing their production capacity and saved them over £10,000 per annum.

Air leakage is still a major cause of wasted money and energy within compressed air systems. It is estimated that the average compressed air system loses 30 per cent of the air it produces through leaks in the system. In some cases, we have found leakage levels as high as 67 per cent.

We often see compressed air systems with around 150 to 300 leaks, and a company using 50m3 of compressed air per minute could potentially save around £63,000 if they were to have them repaired. Leaks are simple to identify and rectify, and it’s cost-effective; the average cost of a Mattei leak detection survey is less than 10 per cent of the overall leakage costs. Typically an 800 per cent return on investment is delivered, and customers will generally see a payback within three to six months.

Q: What are the main barriers to UK plant owners/operators improving their use of compressors technology?

AJ: In some cases it is simply a lack of knowledge, but even when presented with the facts and figures about the significant cost savings that can be achieved we still sometimes face a certain amount of unwillingness, or a lack of funds. We have offered solutions where the payback is just a few months, but many companies still don’t take the opportunity to improve their systems.

It is our belief that not enough managing, financial or engineering directors are really aware of the potential savings that can be achieved by improving the efficiency of a compressed air system - therefore perhaps not realising it is a golden opportunity for their business to reduce energy usage, carbon emissions and costs.

It should also be noted that as around 75 per cent of the five-year cost of ownership (including the capital purchase price) comes from electrical consumption it is critical that consideration be given to the running cost of a compressor, rather than just the initial purchase price.

It is important to remember that while investing in a new compressor can significantly reduce energy use, any savings could be completely negated if the new machine is added to an inefficient air treatment and pipework distribution system with numerous leaks. Even the most energy efficient compressor will not make a system like this energy efficient.

Q: Is there any particular aspect of the technology being underused at present, and if so why?

AJ: Compressors generate a lot of heat, and in some installations this can be recovered and put to good use in the production process, for water heating, for example, or - although not as efficient - local space heating.

However, heat recovery is still not that widely used - this is very often simply down to system design i.e. the hot water is used across the other side of the factory/plant to where the compressor is sited.

We would suggest that the potential savings, particularly with hot water generation, might mean it is worthwhile relocating the compressor/s. Certainly in new build projects more thought should be given to this.

Q: What support is available to plant owners/operators regarding the above points?

AJ: Companies purchasing compressors can apply for finance through the Energy Efficiency Financing (EEF) scheme operated by the Carbon Trust and its partner Siemens Financial Services. It has been designed so that anticipated energy savings will match or exceed the monthly payments the company has to make, which effectively means that the equipment pays for itself right from the start.

Financing can be arranged for amounts as low as £1,000 and there are potentially no upper limits. Terms are available from one to seven years or longer in certain cases. Successful applications can receive financing either for a single piece of equipment or for a complete solution, including installation, service and maintenance. Further information can be obtained by visiting www.energyefficiencyfinancing.co.uk or by calling Siemens Financial Services on 01753 434 476.

To help end users understand their compressed air needs, assess their system and achieve savings, Mattei offers energy efficiency assessments, system audits and data logging and provides leakage detection surveys.

Q: Any other points?

AJ: The forthcoming ISO 11011 standard, Compressed air - Energy efficiency - Assessment (due to be implemented in 2013), will provide companies with a framework for carrying out efficiency assessments of their compressed air systems, hopefully leading them to make improvements and reduce energy use. It should also standardise the energy audits offered by compressed air companies.