September 2019

38 n ENERGY EFFICIENCY September 2019 www.drivesncontrols.com ...about your flexible interconnect cables & connector problems With many years in-depth industry experience, we can guarantee we have seen every connectivity problem and also solved them. Thats why our team of experts are the perfect resource to solve your connectivity issues. Our products range from flexible interconnect cables to terminal blocks and connectors, all of which are designed to withstand high levels of use and minimise the risk of failure. Email us today at uksales@hitaltech.co.uk Hitaltech UK Ltd, Unit 5 Sovereign Court, Wyrefields, Poulton-Le-Fylde, Lancashire, FY6 8JX Telephone: +44 (0) 1253 899910 www.hitaltech.co.uk The experts in connecting technologies experts... Our experts guarantee they will be able to solve your connectivity problems... C ompressed air is a vital resource, but its production is energy- intensive. Looking at the lifetime costs of owning and operating an air compressor, around 75% of the total is the energy needed to run the system. The initial investment is about 15% of the lifetime costs, while commissioning and maintenance account for the final 10%. In the UK, the cost of energy is high and will only increase in future, but the financial implications of using compressed air should not be a business’s only concern. There is significant pressure on manufacturers to reduce the environmental impact of their operations, and there are incentives for them to do so. The CRC Scheme, for instance, rewards large energy users that improve the efficiency of their operations with tax benefits and financial rebates. So, there are real financial benefits for businesses that make their compressed air systems as efficient as they can be. But how can this be achieved? First, a properly maintained compressed air system is an efficient one. It is inevitable that all systems – even new ones – will leak. A single 3mm-diameter hole can cost more than £1,000 a year in wasted energy. The leakage rate from an unmanaged compressed air system can be as high as 40– 50% of the generated output, and in some applications even higher figures have been recorded. By contrast, a well-maintained system should only lose around 5–10% of the compressed air it generates to leakage. Operating at these levels could reduce energy consumption by as much as 20%. Businesses should therefore ask their equipment suppliers to include leak detection and/or an annual energy audit as part of their service. Similar energy savings can be achieved by using heat-recovery systems. A large amount of the energy consumed by a compressor is converted to heat and diverted away via a cooling medium. Using a recovery system, this can be put to use in other ways, such as for heating domestic or circuit water, or for process support. Indeed, a recovery system can pay for itself in as little as seven months. Further, by upgrading a compressed air system’s drives, motors and speed controls, energy consumption can be cut by 15%. While fixed-speed compressors are generally cheaper than equivalent variable speed/frequency compressors, they can consume 20–70% of their full-load power when idling or running off-load. The additional capital investment in variable speed/frequency compressors can therefore be recouped rapidly through energy savings. The use of“intelligent”control systems, meanwhile, can reduce energy consumption by up to 12%. Electronic sequential controllers can control multiple compressors around a single set pressure, and make them available as needed. These systems can operate up to 16 separate air compressors and can be set to vary pressure according to the requirements of production – for example, providing lower pressures at weekends. Finally, a 9% reduction in energy consumption can be achieved by using multi-pressure systems. Booster compressors can be employed where a limited flow of higher pressure is needed: every 1 bar saved on pressure can save businesses 7% on their electrical running costs. The process of compressing air can be wasteful, and in today's ultra-competitive and environmentally-conscious business environment, companies cannot afford such inefficiencies. But by making some common- sense changes and investing in up-to-date technologies, they can reap the savings long into the future. n Cutting the cost of compressed air Up to 94% of the energy consumed by air compressors can be optimised and recovered The UK uses more than 10TWh of electricity every year to produce compressed air, resulting in more than five million tonnes of CO 2 emissions. This doesn’t need to be the case, argues Boge Compressors’ general manager, Mark Whitmore.