Air compressors are the largest energy consumers in the typical manufacturing plant. Any reductions in demand on the compressed air system can result in real savings to the bottom line. Compressed air leaks are a prime opportunity for low hanging fruit when looking to reduce compressed air demand. Compressed air is one of the most expensive “utilities” in your plant and is often the most overlooked in regards to potential energy savings.
For example; a ¼” compressed air leak at 100psig consumes the equivalent of what a 25HP air compressor will produce. Not only is this a significant demand on your system, it can cost approximately $12,000 on your electric bill. This article will explore simple ways to identify and reduce air leaks which can ultimately lower your overall compressed air demand and in turn provide significant savings on your electric bill and ultimately the bottom line.
Cost of Uncontrolled Demand
To gain understanding about how important it is to address compressed air leaks, let’s take a look at some commonly found leak sizes and how much they are costing you on your electric bill (See photo to the right). The chart details how much an air leak can cost and how many CFM it consumes. As you can see the costs of air leaks can be substantial. The increased air demand caused by leaks puts an unnecessary strain on your compressed air system, which may increase unexpected downtime; it also has a very tangible effect on your electric bill.
Common Sources of Leaks and Inefficient Air Uses
The first question to ask is how much a can a leak cost. The next question is how to identify a leak and where to look for common sources of compressed air leaks.
Some of the most common leaks and inefficient/unproductive uses of compressed air can be found in the list below:
• Air hoses and air hose connections
• Open blow-offs
• Worn disconnects
• Leaking or failed drains
• Failed seals, o-rings, or gaskets
• Inappropriate air uses such as air brooms or as personal air cooling
• Unused process equipment
• Using compressed air to cool cabinets such as control or electric panels
Now that we have identified some usual sources of air leaks and inappropriate uses of compressed air, we can look at some ways to reduce your overall inefficient uses of compressed air.
First and foremost your operation should establish a program to find and reduce leaks. This can be as simple as walking the plant during a non-production period and addressing the audible leaks, using a solution of soap and water to visibly identify leaks, or by using an ultrasonic leak detector to more accurately identify the source of an air leak and to detect the inaudible leaks. An ultrasonic leak detector is the most accurate method of leak detection. Having a leak audit performed efficiently identifies sources of leaks and most leak audits can quantify the cost of leaks. This can easily be used to justify the purchase of your own leak detector or to have a leak audit performed by others.
Another method of reducing air leaks or inappropriate uses of compressed air is employee education. Educate your employees about how much a leak can cost the company. Some facilities have even adopted programs rewarding employees for reporting air leaks or reducing compressed air demand for their departments. A $10 gift card reward can more than pay for itself when the cost of air leaks are realized.
Inefficient Uses Of Compressed Air
Some of the items listed above aren’t what most consider an actual leak in your compressed air system. Using compressed air to cool or clean your work area, cooling electrical or control panels, open blow-offs used to cool or move product, and supplying air to unused equipment may be what comes to mind when you think of air leak. However these unregulated or inefficient uses of compressed air can be just as bad if not worse. Listed below are few ways to address these issues:
• Use of engineered nozzles- Open blow-offs used to move or cool product may seem necessary to maintain production, however typically these open blow-offs can be replaced with nozzles designed to reduce compressed air consumption while accomplishing the same task.
• Installing cutoff valves before unused equipment- Production schedules can be constantly changing. Equipment used in one process one week may not be used the next. Identify production equipment that may be in use and valve off the compressed air line supplying the equipment.
• Use of cabinet coolers- Using compressed air to cool electrical cabinets may be effective but it is also a very inefficient use of compressed air. Identify where this is happening and take steps to provide more efficient methods of controlling the temperature of the cabinet. Specific cabinet cooling units are more efficient and can remove significant demand from your compressed air system.
Continued Maintenance Program
Finally, once you have identified the leaks and inappropriate air uses, the next step, as obvious as it may sound, is to fix the leak. Some facilities actually coordinate leak repair schedules with their compressor maintenance schedules. So when they are performing a quarterly maintenance on their air compressors they also repair any leaks identified since their last preventative maintenance service. Air leaks and inefficient compressed air uses will continue to develop so it is important to recognize they should also be addressed regularly.