Faced with growing competition, high energy costs, increased regulation and more aggressive sustainability goals, facility owners and plant managers are under extraordinary pressure to reduce expenses, while achieving greater productivity and energy efficiency. Most industries use some form of air or gas compression to generate power to run equipment, tools and plant processes. It is an extremely convenient source of power, often referred to as the fourth utility. Yet, in many cases it is deployed inefficiently.
The US Department of Energy (DoE) estimates 30% to 50% of compressed air power is lost during operation. Those losses can be a result of leaks, poor maintenance, bad system design, wasted heat and/or pressure losses. This is why industries are making commitments to increase energy efficiency.
For example, nearly 160 leading manufacturers and industrial-scale organisations have partnered with the DoE on its Better Plant Initiative and signed a voluntary pledge to reduce their energy intensity by 25% over a 10-year period.
Efficiency standards are coming
In addition to self-regulating efforts, government bodies and industry groups are driving more stringent industry standards to ensure today’s air-compressor systems meet peak energy efficiency and performance targets. Currently, compliance with proposed compressor standards is voluntary in the US and Europe, but emerging regulatory developments are likely to change that.
Governing bodies leading the push for implementation of minimum efficiency standards include the European Union, which issued the Ecodesign Preparatory Study on Compressors (ENER Lot 31) in 2009, and the DoE Office of Energy Efficiency and Renewable Energy (EERE).
Industry groups, such as the European Association of Manufacturers of Compressors, Vacuum Pumps, Pneumatic Tools and Allied Equipment (Pneurop) and the Compressed Air & Gas Institute (CAGI), drive the adoption of uniform, voluntary standards and provide many services, including research, education, information gathering and distribution and training to end users.
These efforts are designed to increase the overall energy efficiency of compressed-air products on the market while promoting co-operation, awareness and compliance with industry standardisation.
Although the scope of US standards for air compressors has only begun to take shape, industry groups agree that the end result of this energy standardisation will likely be the promotion of minimum efficiency standards, product-testing procedures, certification and enforcement of standards and energy-efficiency labelling for air compressors. These anticipated changes will drive research and development teams to push the boundaries of efficiency with innovations in compressor technology as well as systems improvements, proactive service strategies and maintenance offerings for compression systems.
New compression solutions are already coming to market to help manufacturers significantly reduce their energy costs. For example, Ingersoll Rand recently introduced their Next Generation R-Series line of rotary-screw compressors that improve energy efficiency by up to 16%.
Good for business
Manufacturers are motivated to gain a competitive edge by delivering greater performance and energy efficiency. However, when it comes to compressed air, energy efficiency cannot come at the cost of reliability because plants depends on a reliable source of power to maintain their productivity. This evolution within the industry leads to numerous queries: What can manufacturers and customers anticipate? When will they be required to comply with new energy standards and future regulations? And how can facility managers benefit from using high-efficiency air compressors to reduce costs, improve energy savings and boost performance?
There are advanced compressed-air technologies available that are capable of providing improved performance, while reducing the customers’ energy footprint. It is important to note that these improvements can be achieved while maintaining the reliable supply of compressed air that is required for highly effective operations.
Just 10% to 20% of the energy input to a compressed-air system reaches the point of end use. The rest is converted to heat or is lost through leaks. The costs from lost energy can run into the millions of dollars for a large operation.
To lower energy use and costs, the Ingersoll Rand Next Generation R-Series air compressor has been engineered to require less energy input and more capacity for typical applications, regardless of load. At the core of this model is an innovative air-end, which is the most vital component of every air compressor.
Rotary screw compressors use rotating, meshing male and female helical rotors to compress air. These rotors and their housing contain the air-end, which requires complex engineering to improve, because a change to one factor can have a major impact on another. For example, changing the pressure ratio can increase internal air leakage, desired rotor speed and exhaust temperature.
This is where expert engineering is critical and Ingersoll Rand has accomplished this by applying highly sophisticated modelling to re-design the convex and concave rotor profiles for optimised airflow.
Today’s compressors with advanced airends enable facilities to meet their demand with smaller compressors that consume less energy. Ingersoll Rand analytics show that energy use can be reduced, and by using more efficient compressors and applying a comprehensive service programme, the total cost of ownership of the compressor can be reduced by up to 20%.
Variable speed drive
Rather than controlling a compressor by running the motor at full speed, and then stopping when the air has been compressed to the desired pressure, a variable speed drive (VSD) regulates the delivery capacity based on actual need, thus avoiding wasteful energy loss associated with load/no-load operation.
The Ingersoll Rand Next Generation R-Series with VSD can save up to 35% in energy use, over a fixed-speed compressor. Operating a machine at variable speed allows the compressor to deliver compressed air at constant pressure over a wide range of capacity, up to 75% turn down depending on model and pressure rating
With a fixed-speed air compressor, starting up the drive motor creates a huge energy draw that can be as much as 800% of the full load-running current. Ingersoll Rand’s motor and drive system limits the in-rush current to less than 100%. This significant decrease in the starting load minimises peak power charges – thus lowering energy use.
The design of today’s advanced air-compressor packages use computational modelling to minimise losses at the suction point and through the compression and post-compression processes throughout the machine. Reducing pressure drops cuts the energy consumed in order to raise the pressure of the suction air to the customer’s demand. Improvements in inlet valve geometry and compressed airflow paths fully leverage the new air-end design, and obtain a 15% increase in capacity for the same power consumption.
Advanced air compressors provide additional opportunities to enhance energy efficiencies via remote monitoring. This allows users to control, manage and identify maintenance needs on air compressor systems through their desktop or laptop computers. Users can adjust compressor settings and programme compressors according to specific events through real-time clock schedules. With remote monitoring, users can make better decisions, in a more timely manner so that downtime can be minimised or eliminated.
Air compressors that use controllers can automatically adjust settings to minimise downtime and energy consumption. The compressor automatically reacts to key parameters, such as airflow-pressure rating, operating cycle and energy consumption and then notifies users of the activity.
In addition, air compressors with adaptive controllers continuously monitor key performance parameters and automatically adjust settings to meet a specific application’s needs. Adaptive controllers use advanced control algorithms that automatically adapt to the environment. This delivers better performance, reduced downtime risks and energy conservation, providing built-in performance analysis for a wide range of load requirements.
As energy costs increase, facility managers in virtually every industry look for new ways to improve efficiencies while lowering costs. Air-compressor systems are vital to these industries, yet billions of dollars in the US alone are wasted each year due to inefficient systems.
In addition to lowering energy costs and achieving greater uptime, all facilities can benefit from reducing negative impact on the environment by reducing energy consumption. Industry standards will increase energy efficiency and ultimately help manufacturers and industrial users increase their competitiveness – without compromising safety and reliability.
While today’s energy standards are voluntary, at some future date, they may become mandated by the US Congress or the DoE, which is authorised to enact legislation. Air-compressor manufacturers are already achieving energy-efficiency and performance improvements through sophisticated engineering and advanced technologies.
Working hand-in-hand, industry standardisation and manufacturers will pave the way toward greater future improvements in energy efficiency, optimised performance, reliability and decreasing environmental impact.