Atlas Copco Launches its Most Energy-Efficient Oil-Free Compressor Ever: the ZH 350+

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Atlas Copco announces the launch of the ZH 350+, a high-speed 3-stage turbo oil-free compressor (350kW, 7-8 bar) which is 4% more energy-efficient than the company's top-performing oil-free compressors.

ZH 350+

Atlas Copco's new ZH 350+ energy-efficient turbo compressor

The reliability and energy performance of the ZH 350+ is proof of Atlas Copco's ongoing commitment to its customers' productivity.

Antwerp, 4 April 2011: Atlas Copco has announced the launch of a new, highly energy-efficient high-speed 3-stage turbo oil-free compressor at a press conference held today at the ComVac fair taking place at the Hannover Messe (Germany). The ZH 350+ is the most energy-efficient oil-free compressor ever built at Atlas Copco. It is the first medium pressure industrial three-stage centrifugal compressor to be commercialized with high-speed motors and without a gearbox The ZH 350+ is designed for the pharmaceutical, electronics, aviation, automotive and other industries that rely on high-quality, 100% oil-free air. It offers outstanding energy savings as compared to conventional turbo compressors and is aimed at customers who wish to invest in the highest compressor performance in terms of energy efficiency and reliability.

The exclusive design of Atlas Copco’s ZH 350+ (350kW, 7-8 bar) oil-free high-speed drive centrifugal compressor is the result of intensive R&D and is an in-house innovation success story.

Atlas Copco is proud to set the standard for compressed air energy efficiency, says Chris Lybaert, President of Atlas Copco’s Oil-free Air Division. “The reliability and energy performance of the ZH350+ is proof of Atlas Copco’s ongoing commitment to its customers’ productivity.”

The ZH 350+ is up to 4% more energy-efficient than the company’s top-performing oil-free compressors. The new turbo compressor’s extremely low package power consumption is attributable to five key design choices:

First, The ZH350+’s three-stage design uses today’s best-performing technology to achieve high thermodynamic efficiency and low power consumption. A three-stage design is widely recognized as being the most efficient design for achieving compression between 7 and 11 bar with a turbo compressor. This new “three-stage turbo” design results in average lifecycle costs which are lower by 3 % as compared to an oil-free screw design and by 18 % when compared to a two stage turbo design. These estimates are based on figures provided in the paper: Proceedings of ASME Turbo Expo 2008: Power for Land, Sea and Air, June 9-13, 2008, Berlin, Germany. Paper Ref No.: GT 2008-51353.)

Second, the ZH 350+ completely eliminates the gearbox and thereby also the transmission losses associated with a gearbox. Transmission losses can result in a reduction of energy efficiency of up to 9 % in compressors in the 350 kW range.

Third, the ZH 350+ has titanium impellers, which are not only more reliable, but also permit faster load-unload cycles. The gain in speed results in reduced power losses in times of low air demand.

Fourth, optimally sized coolers significantly reduce pressure drop, impacting stability of subsequent compression changes. The design also features an enhanced heat transfer area.

Fifth, the system blows off before the aftercooler, which means that minimal compressed air is lost when air demand decreases.

The combined reduction in air losses, pressure drops, and transmission losses result in a compressor which is 4% more energy-efficient than the company’s top-performing compressors, under comparable operating conditions. Further energy savings are possible with the new rotary drum heat-of-compression dryer (MD/ND) for centrifugal compressors which are being launched at the Hannover Messe. These dryers are also compatible with the ZH 350+, making it an ideal choice for environmentally respectful manufacturing facilities.

The ZH 350+ was certified ISO 8573-1 (2010) CLASS 0 with regard to oil content by the independent Technischer Überwachungs-Verein (German Technical Monitoring Association), or ‘TÜV’ on 30 March 2011.

The new ZH 350+ will be on display at the Atlas Copco booth (Hall 26, stand B40), along with complete product documentation. The ZH 350+ units will be shipping to the first customers in June 2011.

Atlas Copco is an industrial group with world-leading positions in compressors, construction and mining equipment, power tools and assembly systems. The Group delivers sustainable solutions for increased customer productivity through innovative products and services. Founded 1873, the company is based in Stockholm, Sweden, and has a global reach spanning more than 170 countries. In 2010, Atlas Copco had about 33 000 employees and revenues of BSEK 70 (BEUR 7.3). Learn more at .

Oil-free Air is a division within Atlas Copco's Compressor Technique business area. It develops, manufactures, and markets oil-free air compressors for all kind of industries worldwide where the air quality is vital, and oil-injected compressors for less critical applications. The division focuses on air optimization systems and quality air solutions to further improve customers’ productivity. The divisional headquarters for the division is located in Shanghai with main production facilities in Belgium, China, India and Brazil.


More information, including high-resolution digital photographs, a product brochure and the list of spokespersons may be downloaded from


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