Compressed air is one of the most costly kinds of energy in industrial processes, frequently consuming more energy than other equipment. One horsepower of compressed air necessitates the use of eight horsepower of energy. Many air compressors have efficiency as low as 10%, so there’s always potential for improvement. Fortunately, 50% of compressed air systems in small to medium-sized industrial buildings provide low-cost energy reduction options.
Efficiency of an Air Compressor
What factors determine the energy efficiency of an air compressor? Type, model, size, motor power rating, system design, control methods, usage, and maintenance schedule are examples of such factors. The primary cause of inefficient air compression is heat loss produced by the higher temperature of pressured air and friction created by the system’s many moving elements.
When determining air compressor efficiency, it is critical to consider the complete system, which includes not only the air compressor but also supply lines, air storage tanks, air dryers, receivers, and after-coolers. You may save a lot of money and energy by making the correct changes to your compressed air system.
What Factors Cause Inefficiency in Air Compressors?
Many reasons might lead to an inefficient air compressor. When any of the following causes are at action, air compressor performance may become less efficient over time:
- Poor quality air intake: The effectiveness of an air compressor can be greatly reduced if the incoming air is excessively hot, includes contaminants, or is humid.
- Controls for uneven air pressure: The air compressor controls produce inconsistent or continuous high pressure. When air compressors operate at or near maximum pressure, they place additional strain on the system and degrade efficiency.
- Design defects in the system: Design flaws in the system can lead an air compressor to become less efficient. Improperly sized distribution systems, a lack of a recovery system and increased heat waste, needless bends in the pipes, and unrepaired leaks are examples of design defects.
- Mismatched air compressor: The air compressor does not match or is inadequately calibrated to your devices’ compressed air demands. When air compressors are not properly suited to the application, their efficiency and overall performance suffer dramatically.
- Reduced pressure: Pressure reductions in your air compressor system can have a significant influence on the efficiency of your air compressor. Inadequately sized pipes, high moisture, filthy filters, or extended air travel lengths can all cause pressure drops.
- Inconsistent maintenance: Inconsistent maintenance causes the system to wear prematurely, increasing repair costs. Because of the quantity of moving components and the high usage of these systems, failing to establish a regular maintenance programme might render air compressors ineffective.
How to Boost Compressor Efficiency
Increasing air compressor efficiency generally begins with evaluating what variables are causing the system to wear out. To offer optimal efficiency, energy-efficient compressors rely on both the controls and the design.
For the most efficient air compressor system, well tuned controls that operate closer to the lowest pressure and a well-maintained system design that meets the application are required.
Improve the efficiency of your system by implementing the following strategies:
- Improve the air intake quality.
- Match the controls on the air compressor.
- Improve the system’s design.
- Consider your compressed air requirements.
- Reduce pressure decrease.
- Keep your compressor running smoothly.
Improve the Air Intake Quality
The air compression system’s performance is influenced by three components:
- Temperature: The density of the air is determined by the temperature of the intake air. Because cool air takes less energy to compress, it is significantly more efficient to pump into the air compressor system. Avoid utilizing hot air, which has a lesser density, since it can diminish your output greatly.
- Composition: Clean intake air allows compressed air to flow more freely through the system. Inside an air compressor, dirt, dust, and other pollutants in the air will build. These impurities can accumulate on critical components, causing wear and reducing storage capacity.
- Moisture: Moisture may be damaging to an air compression system because it collects inside the system and causes components to corrode. This may result in wear and tear, leaks, and diminished storage capacity. Dry air is less likely to cause harm to your air compression system and equipment at the point of usage.
Complement the Air Compressor Controls
Air compressor controls match the output of the compressor to the needs of the compressor system, which may include a single compressor or numerous compressors. Such controls are critical for air compressor system efficiency and performance.
Compressed air systems are intended to maintain a certain pressure range while delivering a volume of air that fluctuates with end-user needs. When the pressure hits a specific level, the control system reduces compressor output. When the pressure drops, the compressor output increases.
The most accurate control systems can keep average pressure low while still meeting system requirements. Failure to meet system criteria may result in equipment malfunction. This is why it is critical to align system controls with storage capacity.
The following adjustments can help single compressors run more efficiently:
- Compressors are turned on and off based on pressure using start and stop controls.
- The compressor is loaded and unloaded using the load and unload operations.
- Modulating controls regulate flow requirements, whereas multistep controls allow compressors to run at partial loads.
- Auto-Control and Dual-controls allow you to choose between start/stop and load/unload.
- Variable displacement can function in two or more partially loaded states.
- Varied speed drives continually vary the speed of the drive motor to satisfy variable demand requirements.
- System master controls are used in systems with many compressors to coordinate all of the operations required to optimize compressed air.
- When the complexity of a compressed air system surpasses the capability of local and network controls, system master controls can coordinate the system. To improve maintenance functions, such controllers may monitor system components and trend data.
- Pressure and flow controllers store greater pressure air that may then be utilised to satisfy demand changes.
A well-designed system should include the following features:
- Demand control
- Controls for the compressor
- Excellent signal placements
- Overall control strategy
The basic purpose of such a system is to distribute compressed air at the lowest steady pressure possible while supporting fluctuation with greater pressure compressed air stored in the system.
Sequencing controls for numerous compressors can satisfy demand by running compressors to meet system loads while turning them off when not needed. Network controls also aid in the management of system loads.
Enhance System Design
There are six approaches to enhance your air compressor system’s design.
- Make the route straighter. Narrow or steep bends in delivery lines can increase friction and pressure decreases in the system, resulting in less pressure reaching the point of application. A superior design with fewer bends and loops should provide higher pressure with the same amount of energy.
- When necessary, conserve energy. A storage tank, also known as a receiver, can cushion short-term demand fluctuations and decrease on/off cycle. When demand is at its peak, a tank can also keep system pressure from going below the minimum pressure requirements. When there is a pressure decrease, the system pressure rises, resulting in lost air pressure. The size of the tank is determined by the power of the compressor. A 50-gallon air receiver tank, for example, is required for a 50-horsepower air compressor.
- The intake air should be cooled. Because the energy required to compress cold air is less than that necessary to compress warmer air, you can lower the energy required for compression by relocating the compressor intake outside in a shaded region. A temperature drop of 20 degrees Fahrenheit, for example, may reduce running expenses by about 3.8%.
- Make use of numerous little compressors. Oversized air compressors can be inefficient since they require more energy per unit while only partially loaded. Such systems may benefit from the employment of a large number of smaller compressors with sequencing controls, allowing elements of the system to be turned off simply by turning off some of the compressors.
- Recycle waste heat. Waste heat may be utilized to boil water and heat water for space heating. A heat recovery machine configured appropriately may recover 50-90% of the electrical energy consumed in air compression.
- Locate near high-demand locations. It is simpler to satisfy demand with less total compressor capacity by placing air receivers near sources of high demand.
Consider your compressed air requirements.
- Look at the load profile. A well built compressed air system should take the load profile into account. If air demand varies widely, the system must operate effectively even while only partially loaded. When there are huge swings in demand, several compressors will enable more economical energy utilization.
- Reduce fake demand. The surplus air volume required for uncontrolled usage while employing greater pressure than required for applications is referred to as artificial demand. If a system produces wasted air when an application expects 50 psi but only obtains 90 psi. Pressure regulators at the point of usage can help to reduce artificial demand.
- Determine the necessary pressure. System losses from filters, pipework, separators, and dryers must be included into required pressure levels. Increased discharge pressure will raise demand for uncontrolled usages such as leaks. In other words, when pressure grows, so will inefficiency. Because of the use of unregulated air, a 2-psi rise in header pressure can increase energy consumption by up to 1%. To save energy, think about how to obtain excellent performance while lowering system pressure.
- Examine the appropriate supply and demand. Check that air compressors are not excessively big for their intended usage. Consider all end-use applications, measuring the volume of air required for each. A broad examination of your complete compressed air system should aid in the investigation of distribution system problems and the reduction of incorrect air utilization.
- Use block diagrams and pressure profiles to help you. Block diagrams will aid in the identification of all components in an air compression system. A pressure profile indicates pressure dips in the system, which should give input for controlling the system. To complete a pressure profile, measure the compressor’s input, the difference across the air/lubricant separator, and the interstage for multistage compressors. You can detect system interruptions, intermittent loads, system changes, and general circumstances by data logging system pressures and airflow. Variations in pressure and airflow may be regulated using system controls to have the least impact on output.
- Make use of compressed air storage. Storage can regulate demand events during demand peaks by slowing degradation and lowering pressure drop. It can also safeguard important activities from other system events by shutting down a compressor if necessary.
Reduce Pressure Drop
As compressed air passes through the distribution system, pressure dips occur. Excessive pressure dips might impair performance and increase energy use. Pressure decreases upstream of the compressor signal resulting in decreased end-user operating pressure. Higher pressures are required to fulfill the compressor control parameters. Reduce pressure drops in the system before adding capacity or raising system pressure. For optimal performance, compressed air equipment should be operated at the lowest efficient operating pressure.
Reduce pressure decreases by doing the following:
- Maintain the correct system design. The use of insufficient pipe size between the distribution header and the producing equipment is the most prevalent cause of excessive pressure drop. This can occur if you select pipework based on the projected average compressed air demand rather than the maximum flow rate.
- Maintain air filtration and drying devices to keep moisture at bay.
- Ensure that filters are clean and clear of debris, which inhibits airflow and causes pressure dips. Maintaining and replacing filter components on time is crucial for decreasing pressure loss.
- Select separators, dryers, filters, and aftercoolers with the lowest pressure drop feasible. The average pressure differential for a filter, hose, and pressure regulator is 7 pounds per square inch (psid).
- Select regulators, hoses, lubricators, and connectors that provide the highest performance at the smallest pressure differential.
- Reduce the amount of time that air goes through the compressed air system.
Many tools can function well with an air supply pressure of 80 pounds per square inch gauge (psig) or less. You may minimize leakage rates, boost capacity, and save money by lowering the air compressor discharge pressure. Reduced operating pressure, on the other hand, may necessitate changes to pressure regulators, filters, and storage capacity. Remember that if system pressure goes below the minimal limits, equipment may cease to work correctly.
By lowering pressure drops, a system can work more effectively at lower pressures. Operating machinery that consumes a considerable volume of compressed air at lower pressure levels can result in significant energy savings. Larger air cylinders may be required to ensure appropriate performance at lower pressure levels, but the energy savings should outweigh the cost of the extra equipment.
Keep Your Compressor Running
Air compression devices that are not properly maintained might waste energy and money. As a result, it is critical to inspect your systems on a regular basis for leaks, premature wear and tear, and the accumulation of impurities.
Repair any leaks
Wasted air is the most common source of energy loss in air compression systems, accounting for up to 30% of a compressor’s output. Even little leaks can be expensive, releasing substantial volumes of air over time if not repaired. Keep in mind that the amount of air lost is related to the magnitude of the leak and the supply pressure in the system.
Leaks not only waste energy, but they also reduce system pressure, making air tools less efficient. Because there is less pressure, equipment will operate longer to produce the same outcomes. Increased running duration necessitates more maintenance and possibly downtime.
Leak detection and repair can minimize energy loss to less than 10% of compressor output. Pressure regulators, open condensate traps and shut-off valves, disconnects, pipe joints, thread sealants, couplings, hoses, tubes, and fittings are common locations for leaks in the compressed air system.
Take measurements of the time it takes the compressor to load and unload to estimate leakage in your compressed air system. Because of pressure drops produced by leaks, air leaks force the compressor to cycle on and off. Using the following formula, compute the percentage of total leakage: Leakage (%) = [(on-load time in minutes multiplied by 100) / (on-load time + off-load time in minutes)]. The proportion should be less than 10% in a well-maintained system. A badly maintained system will indicate 20% or more leakage.
- Leak detection: By identifying hissing noises, an ultrasonic acoustic detector has the highest probability of locating leaks. Ultrasonic detectors provide the advantages of speed, precision, ease of use, variety, and the ability to execute tests while the device is operating.
If you don’t have an ultrasonic leak detector, you can use paint brushes to spray soapy water to potential issue places.
- Repairing a leak: Repairing a leak may be as simple as tightening connections after you’ve found it. However, couplings, pipe sections, hoses, joints, traps, fittings, and drains may also need to be replaced. Make sure to use the right thread sealant.
Until you can repair a leak, you can decrease leaks by decreasing the compressed air system pressure. Maintain the system header pressure at the lowest possible level to reduce leakage.
- Prevention. A proper leak prevention programme can aid in the detection and repair of future leaks. It will also aid in the upkeep of an efficient, reliable, and cost-effective air compression system. A leak prevention programme can help by accomplishing the following things:
- Calculate the cost of air leaks. This will be used to assess the efficacy of fixes.
- Locate any leaks. While an ultrasonic acoustic leak detector is the most effective, a hand-held meter may also be used to detect leaks.
- Keep track of the leaks. Keep track of the amount, location, kind, and projected cost of leaks so you can see where and how they occur.
- Larger leakage should be prioritized.
- Adjust the dials to get the most out of your energy.
- Repairs should be documented. Such documentation might point to the equipment that is generating recurring issues.
- Periodic audits Periodic inspections will help maintain your system running smoothly.
Change the filters.
Filters are used to guarantee that clean air is delivered to end consumers. Filters can become clogged with dust, grime, and oil, resulting in a decline in system air pressure. When filters are not cleaned, pressure decreases might occur, necessitating more energy to maintain the same pressure. Also, employ low-pressure drop, long-life filters that are sized according to the maximum rate of flow.
Ensure that procedures for maintaining the compressed air system are in place and that staff are adequately educated in these processes. This should keep the system functioning well for many years to come.
Fortunately, there are several methods for increasing the effectiveness of your compressed air system. There’s no reason why your system can’t give cost savings as well as good performance with correct maintenance.
For more information about air compressor distributor, please visit https://www.ldckomp.com.my/