Company Announcement - Variable Speed Drive compressor technology from quality air equipment and service solutions specialist, Atlas Copco, is the key to sustainable energy-efficient operation and low total cost of ownership. With declining global energy resources and escalating electricity costs, twenty-first century mining and industry around the world face similar challenges and share the same objectives, namely to minimise cost and maximise production. End-users are compelled to install equipment that combines high performance with efficient operation for optimum productivity and lowest possible operational costs.

To assist end-users in meeting these objectives, Atlas Copco focuses on end-to-end energy efficient operation in the development and design of compressors. In addition to quality, the focal point is to minimise the cost of each cubic meter of compressed air produced to be able to supply compressors that deliver best-case-scenarios where reliability, performance and efficiency is concerned. VSD (frequency-controlled) technology forms part of Atlas Copco’s strong energy saving drive to achieve maximum energy efficiency and sustainable productivity.

The company’s range of oil-injected rotary screw compressors - GA VSD (GA 5-90 kW with world class FAD (Free Air Delivery), GA 90 – 500 kW for larger air requirements, and the more recent highly compact 7-37 GA VSD+ clearly reflect this drive towards achieving optimum efficiency during compressed air delivery. “Energy consumption typically represents over 70% of a compressor’s life cycle cost which opens up tremendous energy saving opportunities,” according to Atlas Copco Compressor Technique’s Business Line Managers for Oil Free Air and Industrial Air Division respectively, Pieter van Wyk and Charl Ackerman. Giving a broad outline of VSD, a technology which was pioneered by Atlas Copco in 1994, Van Wyk confirms that energy savings of up to 35% can be realised. “The VSD compressor perfectly matches air supply to air demand in processes where air demand profiles fluctuate. By varying the speed drive of the drive motor, the compressor follows fluctuation in production demand; as air demand declines or is reduced, the GA VSD lowers the delivered flow and consequently the power consumption.”

Van Wyk adds that motor speed regulation is the most efficient compressor control method where air demand varies “because the inefficient transition period between full and no load is eliminated which avoids excessive off-load power consumption. Maintaining the net pressure band within 0.10 bar (15 psi), greatly reduces the overall average working pressure and energy costs.” Soft start will lend further flexibility as gradual motor ramp-up avoids electricity surges. Reduced carbon dioxide emissions is another benefit offered by VSD technology.
 
Ackerman points out that the most efficient compressor package incorporates optimisation of all the compressor elements (oil-injection, flow and temperature) to maximise output and minimise losses. In the development of the GA VSD, substantial efforts were made to reduce all types of losses, whether flow-related, mechanical or electrical. The highly compact oil-injected rotary screw 7-37 GA VSD+ compressor range, introduced by Atlas Copco in April 2013, serves as an excellent example where Atlas Copco evaluated every part in the compressor to ensure across-the-board optimisation:
 

A more efficient fan, a robust air intake system, the elimination of all blow-off losses, and the best electronic components together with the new drive train, add up to breakthrough energy-efficiency. Better performances are delivered, even at full load, while consuming on average 50% less energy compared to a traditional idling compressor.

“Available from 7 to 37 kW, the GA VSD+ is another 15% more efficient than Atlas Copco’s GA 7-37 VSD and operates at lower noise levels,” notes Ackerman. The range also offers a leap forward in Free Air Delivery with improvements of up to 12%. “The GA VSD+ has been completely in-house developed and brings together all our expertise and know-how on energy-efficient compressor technology. The compressor contributes significantly to the green economy needs as this innovation enables all compressor users to switch over to variable speed drive compressors, an important step towards a more sustainable industry.”

Regular service and maintenance by skilled technicians using the right tools and genuine parts are essential for ensuring optimum, reliable and efficient compressor performance and sustainable productivity. Atlas Copco Compressor Technique South Africa’s four service branches in Johannesburg, Durban, Cape Town and Port Elizabeth, supported by ten authorised distributors, take care of customers’ requirements across the country offering turnkey service solutions across the complete Compressor Technique product portfolio.