Upgrade the compressed air generation system at APS Materials’ Waterford facility to deliver certified oil-free air while improving reliability and reducing total running costs. Scope included replacing a 45 kW air-cooled, oil-lubricated fixed-speed screw compressor and downstream oil-removal filtration with an oil-free, variable-speed screw compressor and optimised controls.
Plant Manager Michael O’Sullivan set out to answer a simple question: does better air quality necessarily increase costs? The team’s primary goal was to bolster oil-free reliability. The initial move from “contact-cooled with filtration to achieve oil-free” to true oil-free technology carried a higher upfront price; however, pairing the upgrade with variable speed drive (VSD) control transformed the business case.
APS replaced its legacy 45 kW fixed-speed unit with an oil-free, variable-speed screw compressor (IRN45OF). Given the site’s variable load profile and historic pressure drops across downstream oil-removal filters, VSD control and the removal of oil-related ancillary stages offered a clear path to lower energy use and cleaner air.
• Oil-free screw compressor (IRN45OF) sized to site demand.
• Variable Speed Drive (VSD) to match output to real-time air demand and enable soft starts.
• System pressure optimisation to reduce leakage and avoid unnecessary over-pressurisation.
• Simplified downstream treatment by eliminating oil separators/coalescers associated with lubricated compression.
• Controls tuning and monitoring to maintain stable pressures at lower setpoints.
• Maintenance plan focusing on intake air quality and filtration to protect oil-free elements.
• Full manufacturer support with a bumper-to-bumper 5-year warranty
• Energy savings up to ~35% for APS, driven by VSD part-load efficiency and reduced unloading/idle losses; in more favourable profiles, up to ~40% is achievable.
• Lower system pressure and reduced pressure drop, cutting leakage and further decreasing kWh consumption.
• Cleaner, certified oil-free air without the risk and cost of downstream oil contamination.
• Reduced maintenance: no compressor oil to purchase, manage, or dispose of; fewer oil-related components to service.
• Higher reliability with soft starts and fewer thermal/mechanical stresses.
• Reduced carbon footprint through sustained energy reduction.
• Improved total cost of ownership: energy and maintenance savings offset the higher capital cost, delivering a strong payback.
At APS Waterford, improved air quality did not mean higher operating costs. By moving to a true oil-free, variable-speed screw compressor and optimising system pressure and treatment, the site achieved cleaner air, significantly lower energy use, reduced maintenance, and a smaller carbon footprint—backed by a 5-year manufacturer’s warranty. As Michael O’Sullivan summarises, the VSD oil-free upgrade proved to be a game-changer for performance, reliability, and cost.
Air Compressor, Vacuum Pump, Garage Equipment, Gas Heating & Dust/Fume Extraction Specialists
