ESOS FEATURE
Why it pays to consider the bigger picture regardless of ESOS
Philip McArragher, Technical Manager for HPC Compressed Air Systems investigates
ompressed air has long been essential for a wide range of manufacturing, process and automation technologies and in some situations its importance is underlined by the fact that users regard it as the ‘fifth utility’. Over time the complexity and efficiency of compressed air systems has dramatically increased and today this is even more important as a result of the Energy Savings Opportunities Scheme (ESOS). ESOS is the UK Governments’ response to the EU’s efficiency directive and is essentially a mandatory energy assessment audit applicable to all UK companies with a minimum of 250 employees, or an annual turnover in excess of £42m. It is estimated that generating compressed air accounts for 12% of all industrial energy usage across Europe and whilst the ESOS initiative is a positive step towards a better understanding of energy usage, it does not oblige companies to carry out improvements. However, the commercial reality is that the focus on energy efficiency will only intensify.
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LOOKING AT THE BIGGER PICTURE As the range of compressed air applications grows, so does the demand for increased air quality along with the requirement for optimum reliability and efficiency. However, many ‘systems’ still operate as they did 20 or 30 years ago where, due to a lack of user awareness, they are often referred to as just ‘the compressor’. Therefore the bigger picture of the system as a whole is ignored. To gain the most from optimising compressed air system efficiency though requires an integrated, system approach. When talking about energy costs, users are usually able to quote the price per Kilowatt Hour but hesitate when asked how much their plant’s cooling water costs per cubic metre. Ask them how much a cubic metre of compressed air costs and the vast majority will be at a complete loss. This is due in part to most purchasing decisions being more concerned with the initial investment cost of the system, instead of accurately considering the long-term operating costs. Even with a perfectly optimised system, energy costs for compressed air
production can amount to approximately 71% of total operating costs, whereas the initial purchase investment (excl. installation) accounts for approximately just 15% and for servicing an additional 14%. The larger the compressor the larger the operating cost element becomes.
ENERGY SAVING POTENTIAL HPC welcomed the results both from an EU study on energy savings in compressed air systems as part of the EU ‘Save II’ project and the ‘Efficient Compressed Air’ campaign (2002 to 2004). These studies, along with the more recent demands of ESOS are making users more aware of the need to comply and to optimise the efficiency of their compressed air systems. Of the 80 billion kilowatt hours required to produce compressed air in Europe since the beginning of the decade, more than 32% could have been saved through
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Figure 1: HPC offers analysis procedures where key data scan be gathered, analysed and documented within a couple of days
“The complexity and
improvements in efficiency, amounting to an annual saving of €2.5 billion (about £1.7 billion) based on average European energy prices. Another fundamental finding of the EU study was that such potential savings could not be realised simply by improving individual components within a system, they could only be achieved through an integrated system optimisation approach, as most non-optimised systems show weaknesses in all areas. To achieve maximum energy efficiency,
efficiency of compressed air systems has dramatically increased and today this is even more important as a result of the Energy Savings Opportunities Scheme”
as many items of compressed air equipment as possible should operate at the same pressure. De-centralised compressor systems, network areas operating at a different pressure, or air quality and the use of small oil-free compressors for the purposes of particular processes, should only be considered in exceptional circumstances. In the long- term, such solutions invariably drive up energy costs and unnecessarily restrict flexibility with regards to possible future plans for expanding production or system modernisation. Until recently, the predominant principle for compressor system design was to opt for the lowest possible purchase cost. This strategy usually resulted in poorly dimensioned compressed air installations comprising completely incompatible system components. Compressed air dryers must be precisely tailored to match compressor outputs and the individual compressors should be correctly sized for compatibility with one another. Only then will a master control system be able to select the correct compressor combination at the appropriate moment. A really efficient compressed air supply can only be achieved through a comprehensive design strategy that meets all specific compressed air requirements and which involves every system
element. As a long established national compressed air provider HPC is perfectly placed to provide these key requirements.
HPC Compressed Air Systems
www.hpccompressors.co.uk 01444 241671
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