Packaged drives cut the cost of compressed air

Pete Tomlins, EnergAir's UK Manager, says: "Energy saving in compressed air is a massive issue right now; by running even a modest-sized compressor house more efficiently, companies could reduce their energy bills by tens of thousands of pounds per annum. Key to improved efficiency is matching air generation closely with demand, and this is difficult to achieve without at least one compressor delivering variable-speed operation. New variable speed drive (VSD) compressors represent a large capital outlay and most compressors are only part-way through their life; hence, a retrofit package at a fraction of the cost makes a lot of sense."

The EnergAir/KEB offering means that end users operating one or more fixed-speed air compressors are now able to buy-in an optimum energy-saving system without the capital outlay required for a completely new VSD air compressor - and ensure that the new variable speed feature will work with virtually any existing installation, regardless of age or brand.

Many compressor manufacturers now offer a VSD version alongside their standard fixed-speed air compressor range, but EnergAir says these compressors are not delivering the energy savings they should because, in many situations, they are not working in unison with other compressors under an effective management control system. The added advantage of the EnergAir/KEB drive upgrade for existing compressors is that it can easily be integrated into an advanced EnergAir control system that is designed to help manage and maximise energy savings in multiple-compressor installations.

EnergAir and KEB software and hardware engineers have worked closely over the last twelve months to integrate the EnergAir control and compressor management software with the VSD motor control parameters; the task has been made easier by common Modbus communication and a wealth of shared experience.

Matt Handley, Managing Director of KEB in the UK, says: "The KEB drives range spans from 0.37kW through to 800kW and so comfortably covers the usual 50kW to 200kW range of most screw-type compressors. We were also impressed with EnergAir's specialist knowledge of compressor control and excited by the prospect of working on both retrofit and OEM solutions."

Over 60 per cent of KEB's EUR140m Global turnover is in VSD drives, hence the company is able to offer guaranteed availability and a global supply and support network. The KEB range of peripheral equipment such as filters and chokes for special requirements and expertise in reducing harmonics also adds to the package of user benefits.

Pete Tomlins, adds: "The VSD drive package has been developed partly as a result of market demand and partly because we see a huge opportunity for a convenient and reliable solution. Compressed air generation is equivalent to about 10 per cent of industry's total electricity usage, rising to 30 per cent in some sectors. By employing an effective drive package such as ours, compressed air distributors can also offer end users significant improvements in air generation efficiency."

Payback periods typically range from six to eighteen months, depending on the size of the installation and the operating schedule; most large installations tend to run 24hrs and show shorter payback periods. To give an example, by installing a VSD retrofit package, and an effective management control system, a site with four 150kW compressors working average shifts could reduce energy usage by over 800,000kWh pa, reducing costs by over £50k pa, based on current energy prices.