Energy efficiency: Work in progress
17 April 2013
Has the EU focussed on the right area with machine efficiency, or should the efficiency of the complete air system be the subject of the forthcoming regulation? Greg Bordiak, technical officer at BCAS (British Compressed Air Society), comments
Compressor manufacturers, like many other manufacturers, are working hard to squeeze the last ounce of energy efficiency from their packaged products. The user, however, is looking for more processing power from their packaged unit, which can include air treatment, controls and an electric motor, whereas the EU wants to legislate the energy efficiency rating of the product.
The standard, ISO 1217, used for positive displacement compressors, identifies acceptance tests from which the elements of an energy statement can be calculated. The statement is known as 'specific energy requirement' and provides for the relationship between packaged compressor input power and output volume flow rate.
The EU has put in place legal provisions to control the efficiency requirements of all equipment that uses energy. The focus of attention is now on compressors which, under the umbrella of the Energy Related Products Directive, are to follow electric motors down the path of reducing energy use.
A consultant - VHK from the Netherlands has been appointed by the EU to produce a report and recommendations on what and how the energy efficiency requirement is to be identified for compressors.
VHK has been liaising with the compressor industry representative PNEUROP, in which BCAS is actively involved. Part of the report that VHK is required to produce is a study to establish the size and energy use of the market. An estimate for the energy use of the total compressor market in the EU produced a result in the region of 240TWh for all compressor technologies.
The PNEUROP working group is developing an argument to restrict the scope of the eventual legal provision so that the appropriate resources can be focussed on identifying the most beneficial sector of the compressor market that can show real energy efficiency savings.
The identity of a basic compressor configuration will have to be representative of the market sector. This then takes the discussion back to what the customer wants in the form of the packaged compressor configuration. The question that needs to be asked is whether a basic compressor configuration can be reconciled with the wants of the customer? PNEUROP is struggling to find a solution to this configuration, which in itself is reducing the scope of what will eventually become the legal provision. A basic configuration for oil flooded rotary compressors is evolving and one for reciprocating compressors is being identified.
The PNEUROP working group met almost once a month during 2012 to provide assistance to VHK so that an industry acceptable proposal for the coming legislation can be put forward for EU agreement.
Its important to remember that although a compressor is deemed efficient, it could still be installed into a system that may not be configured to take advantage of this improved performance. This overall system does not currently have an energy efficient statement of its own.
However, an energy efficient statement for the overall system can soon be obtained using standardised methods and procedures within the ISO 11011 'Compressed air â€” Energy efficiency: Assessment'. The ISO working group led by BCAS met in November 2012 to discuss the comments during the last voting phase where it received 100% support enabling publication of ISO 11011 during the first half of 2013.
The question that remains is what level of energy saving can be achieved by compressor technologies to satisfy the upcoming legal provision from the EU, and how much energy can the customer expect to save from their system? A 10% improvement in energy efficiency for a compressor package may not be possible, but savings of over 10% are certainly possible when it comes to the complete compressed air system.