Drives & Controls September 2022

30 n ENERGY EFFICIENCY September 2022 www.drivesncontrols.com Inverter-controlled hydraulics cut energy use by up to 90% T he global market for hydraulic equipment is predicted to be worth $42.1bn by 2025, expanding with a CAGR of 2.4%. Although hydraulic systems are used widely around the world, systems that deliver energy savings tailored to individual customers’needs are harder to find. While hydraulics have traditionally been renowned for their power, durability and control, the need for more energy-efficient systems is driving innovation in the sector. One innovator is Oilmek, a Swedish supplier of industrial hydraulic systems. It has developed a technology called Varius that uses frequency inverters and PLCs to control pump motors. The system is claimed to reduce the energy consumed by hydraulic cylinder pumps by 50-90%, resulting in payback periods as short as one to three years. The“unique”technology controls the frequency of the electric motors that power the hydraulic pumps precisely to suit the demands of an application. Users get exactly the control they need, cutting their energy use and costs. This more accurate control allows processes to be optimised, with higher production throughputs and improved end-products. Olimek also claims that the technology is more reliable with fewer interruptions to operations. And because the inverter- controlled movements are smoother, there is less wear and tear on external components. Other benefits that the company claims for its technology include: n lowmaintenance costs; n longer operating lives for the hydraulic oil and the rest of the system; n improved safety because there are fewer hoses and components, meaning there is less risk of leakages and fire; and n a better working environment as a result of lower noise levels and cooler operation. Since Oilmek introduced the Varius technology ten years ago, it has delivered more than 350 of the systems. One of Oilmek’s customers is a Swedish company called Renova, which treats and sorts waste and recyclable materials.“Renova ‘owns’the recycling industry in Gothenburg,” explains Tomas Palm, Olmek’s sales leader. “Because the company is publicly owned, it faces extreme demands to be more environmentally friendly.” When Renova needed a pair of hydraulic systems to make a large heating plant more energy-efficient, it turned to Oilmek and its frequency-controlled technology. Initially, Renova ordered two of the hydraulic systems for the heating plant. It wanted a technology that would operate for many years with minimal maintenance and shutdowns, and maximum energy efficiency. The pumps are powered by high-efficiency induction motors fromWEG. TheW22 motors are designed to produce low noise and vibration levels. Their low energy consumption and maintenance requirements result in a low total cost of ownership (TCO). The motors are also coated in a thin layer of fire-retardant paint, satisfying Renova’s requirements for the systems to have a high level of fire safety. “TheW22 also allows downsizing,”says Palm. “Big process motors are heavy, and standard motors in this application can weigh over 300kg. Using theW22, we’ve been able to lose 100kg of weight. The motor’s reduced noise and vibration levels are also helpful in hydraulic systems that can sometimes produce high- frequency, high-volume sounds.” Based on positive results from its first two installations, Renova has ordered two more and now has four of the hydraulic systems operating in its heating plant. “This is tomorrow's technology,”Palm declares.“It is how all hydraulic systems will look in the future.” n A Swedish company has developed a technology that uses inverters and PLCs to control the operation of hydraulic pumps, resulting in energy savings of up to 90% and payback periods as short as a year. Renova is using the high-efficiency hydraulic pumping systems in a large heating plant in Gothenburg Oilmek’s technology (bottom) uses high-efficiency motors and variable-speed drives to control hydraulic pumps and can avoid the need for control valves used in traditional systems (top)