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It can pay to get specialist advice

04 March 2013

When it comes to ensuring that a new compressor installation is as energy efficient as possible it is, according to Mattei, essential to seek the advice of a compressed air specialist. Here, general manager Andy Jones explains why

When it comes to ensuring that a new compressor installation is as energy efficient as possible it is, according to Mattei, essential to seek the advice of a compressed air specialist. Here, general manager Andy Jones explains why

With energy prices remaining volatile and carbon reduction targets being critical, energy efficiency has become a top priority for many manufacturers. However, not all businesses realise that compressors can have a big impact on their utility bills and carbon emissions, or understand how important it is to ensure the compressors they use are suitably sized and are appropriate for their production processes.

Some businesses have a misconception that compressed air is 'free' once they have invested in the equipment, but the main cost will always be the energy required to produce the compressed air. The initial purchase price actually makes up a very small part of the total lifetime costs. The electricity consumed during operation over a five-year period, meanwhile, typically accounts for around 75% of the total cost of ownership, including the initial capital outlay for the compressor.

In many cases, however, this is completely overlooked during the specification process, because very often the person responsible for specifying the machine is not a compressor specialist. Time and time again we see purchasing decisions being made on a likefor- like replacement basis, or on the recommendation of a general consultant who is not actually experienced in compressor technology, rather than on actual requirements. And because the purchaser - or one of their general consultants - believes they already know what they need, we often find specifications being written before we are even contacted. Sometimes this is based around a specific manufacturer's compressor, or what is already in place.

However, this approach can result in an unsuitable compressor being selected, that won't be efficient for the application.

Replacing like-for-like doesn't mean the new compressor will be automatically right; it could be that a business has had an inefficient system for some time, either because of process/production changes or simply because it was wrongly specified in the first place. We recently found that one company running a 75kW compressor could actually fulfil its compressed air requirements with a 45kW machine, with estimated savings in the region of £10,000 a year.We also see 'oil-free' and 'class zero' air being specified without legitimate reason.

And, since the more stringent the purity, the higher the cost to achieve it, businesses can be unnecessarily wasting thousands of pounds. Similarly, some companies are using variable speed compressors when fixed speed machines would be more appropriate, and vice versa - again wasting energy. A variable speed compressor will only be able to save energy if it's been established that there are true peaks and troughs in the demand for air.

Compressor specialists don't even need huge amounts of information to determine what equipment is required. For example, to make a recommendation, all Mattei needs is an air usage figure (which can be obtained through a seven-day data logging exercise) and the class of air required in accordance with ISO 8573-1:2010. It is also possible that a compressor specialist might arrive at the conclusion that a new compressor isn't required at all. It could be that fixing leaks in the system or upgrading/altering the layout of the pipework could be sufficient to improve performance and efficiency.

And, where 'oil-free' compressors are concerned, a specialist would have the knowledge and experience to identify whether the entire system requires a certain purity, or just a particular area that could perhaps be served by point of use air treatment or a dedicated smaller compressor.

Having said this, unfortunately we do have to accept that there are compressed air companies that are just interested in selling new machines, whether it's in the best interests of the customer or not. So if the purchaser wants an unbiased, independent opinion, or reassurance they have been given the correct advice, they can contact BCAS (British Compressed Air Society).

Replacing a compressor presents an ideal opportunity to improve energy efficiency - so we would strongly urge businesses to seek the advice of a specialist and where possible invest in a data logging exercise before a detailed specification is written.