Most industries rely on compressed air as a major energy source to operate equipment such as pneumatic controls, air tools, pumps, valve actuators, pistons, pneumatic conveying and large-scale processes. Compressed air is clean, safe and convenient, but it can also be an expensive energy source.
Approximately 10% of the electricity supplied to Australian industry is used to compress air. Constantly rising electricity costs have fuelled demand for industrial compressed air systems to deliver greater output for less energy input. The continued effectiveness of compressed air as an industrial power source lies in technological advances in compressor design, control methods, reticulation design and maintenance of systems to ensure optimum operational effectiveness.
Specialist compressed air service companies can inspect, advise and restore systems to maximum operating condition. Maintenance programs are available and recommended to keep systems operational and avoid costly downtime for compressed air-reliant industries. Regular checks and maintenance are essential for continued efficient operation and minimisation of downtime. Like any other piece of expensive machinery, well-maintained systems give users many more years of operating life at low cost. Leading suppliers to offer tailored maintenance programs to suit individual customer needs.
Selecting the right system or upgrading current systems to more sustainable levels of power usage can, in many cases, be cost-negative when energy cost savings are considered.
Existing systems
When upgrading existing systems, viability depends on the system’s maximum efficiency being maintained under its specific operating demands. In existing installations, it is essential to completely and accurately review the efficiencies in the compressor itself and ancillary equipment in relation to the nature of the demand.
- System leaks. Up to 50% of generated air is frequently lost through leaks. These leaks not only waste energy, but can also make the compressor work harder to meet the higher demand. This can shorten equipment life, increase maintenance needs and create unnecessary downtime. A proactive leak detection, repair and maintenance program will help to maintain system efficiency and can significantly reduce energy consumed.
- Variable supply. Use of the minimum appropriate air pressure for the required task can save considerable energy as the work required to compress air is a factor of both pressure as well as volume. Many procedures do not require air at the maximum pressure that the compressed air system can produce. Delivering a higher than necessary pressure results in excessive energy use, excessive equipment wear, artificial demand and higher long-term maintenance costs. In situations where demand varies frequently and rapidly, variable speed drive control (VSD) allows the compressor to automatically adjust its output to meet demand. This minimises energy usage proportionally with demand, which can result in significant power cost savings.
- Pressure drop. A typical system should be designed to maintain a pressure drop of less than 3% between the compressor’s output pressure and the point of use. Pressure drops occur due to friction throughout the reticulation system and is generally a result of poor system design. Unnecessary bends and small-capacity piping also cause friction. Improving the layout, increasing piping diameter and installing smooth bore piping can greatly lower friction and minimise pressure drop. Reducing operating pressure by 100kPa will save around 8% of required input power.
- System ancillary components. Ancillary components such as coalescing filters, air dryers and moisture separators should be specified and installed to match the air quality requirements for the application, otherwise contaminants such as water, dust, dirt and residual hydrocarbons can cause damage to system components and can also cause product spoilage. It is imperative that these items be selected to minimise pressure drop.
New systems
With great advances in compressed air technology today, there is a wide choice of compressor type and sizes to fit every application; however, it requires expert assessment to match a compressed air system to a given application and to ensure it will provide for current and future demands.
There’s a lot to consider when selecting and installing the right compressor. What volume flow rate output do you need? Should you install one or multiple compressors? Is a single or two-stage compressor best? What discharge pressure is required? Do you have a fixed or varying demand? Do you want a compressor that will cater for future growth?
With major advances in global air compressor technologies keeping pace with industry demand, particularly in larger industrial applications, operators now have a wider choice of compressor types and capacities to match specific requirements. Some of these include:
- Permanent magnet, variable frequency (PMV). This innovation to the rotary screw compressor, with either single or two-stage rotary screw configurations, optimises operational integration of the compressor airend, advanced permanent magnet drive motor and variable frequency speed drive technology. This systemic harmony provides a far greater air output with far less energy.
- Advanced two-stage rotary screw technology. Two-stage rotary screw compressors offer the benefits of a single-stage compressor with added efficiency gains and energy savings. This rotary compressor type divides the compression ratio between the two distinct stages, reducing internal efficiency losses and greatly extending bearing life due to reduced applied loads. The machine also requires a smaller drive motor to output equivalent flow rates, thereby saving on energy input.
- Fixed orbit, lubricated compact compressors. This type of compact compressor is rapidly replacing older-style reciprocating (piston) compressors in smaller industry and workshop applications. With a beneficial power-in/air-out ratio, this advanced compressor delivers energy efficiency with minimal moving parts in an ultra-quiet, compact package.
Kaishan Australia can provide Australian industry with know-how and service, with the latest innovations in products covering every conceivable compressed air need. The company also provides a free compressed air assessment service to recommend the right system or upgrade to achieve your specialised needs. In many cases where the existing system is running inefficiently due to leakage, restriction or wear and tear, the company can clearly demonstrate the savings to be achieved through repair or upgrading of the system.