London based Silverstream Technologies partners with Atlas Copco ZS oil-free screw blowers for its innovative fuel saving air lubrication technology for ocean-going vessels
The enormous energy required to power large cruise ships and merchant vessels means, as shipping companies or ship designers ,you are always looking for ways to reduce fuel costs. One recent innovation, incorporating Atlas Copco’s air compressor and blower technology, has been ‘air lubrication’ to reduce hull drag and improve efficiency. Silverstream Technologies is the first company to evidence fuel savings using their patented Silverstream® System.
“ Air lubrication helps our customers to save up to 8% on fuel on larger vessels ”
The air lubrication system employed by Silverstream uses a series of carefully positioned air release units (ARU) on the ship’s hull near the bow, which then creates a carpet of micro-bubbles. This carpet reduces drag, minimizing the amount of fuel required to propel the vessel forward.
Designated as an ‘innovative technology’ within the International Maritime Organisation’s Energy Efficiency Design Index (EEDI), Silverstream® system is seen by many as integral to the future of shipping by reducing Green House Gas emissions.
At the heart of the system is the need for reliable air compressor technology. “The system relies on a constant and dependable supply of compressed air” explained Stephen Potts, Head of Supply Chain at Silverstream. “The Atlas Copco ZS55 oil-free screw blowers provide this – giving us the right combination of cost, performance and reliability.”
Why give full flow when sailing at a low speed? That would be a waste of energy. That is why ZS units are equipped with Variable Speed Drive technology (VSD): you can perfectly follow an ‘optimal flow demand curve’ and tune your flow to your sailing speed. You benefit from a large turndown to further optimize your energy efficiency.
“ ZS systems gives us reliability and pollutant-free output ”
The efficiency of the compressed air system was important. As a fuel-saving measure, air lubrication is more effective when the compressors or blowers used are themselves highly efficient, and Atlas Copco enables a faster return on investment by giving Silverstream Technologies and its customers the right balance of CAPEX and OPEX.
Also, since the air lubrication system releases air directly into the ocean around the vessel, it was important from an environmental perspective to ensure that the air output carried no pollutants.
Stephen Potts explained: “The ZS oil-free system was perfect for Silverstream since it gave us reliability and pollutant-free output, thus supporting the company’s strong environmental position”