Leaks are a hidden nuisance in a compressed air system that can cause thousands of dollars in electricity per year. These leaks on average can account for up to 30% of the operation cost of a compressed air system. A leak will usually occur at connection joints, unions, valves, and fittings. This not only is a huge waste of energy but it can also cause a system to lose pressure along with lowering the life span of the compressor since it will have to run more often to make up for the loss of air from the leak.
There are two common ways to calculate how much compressed air a system is losing due to leaks. The first way is to turn off all of the point of use compressed air devices; once this has been complete turn on the air compressor and record the average time that it takes the compressor to cycle on and off. With the average cycle time you can calculate out the total percentage of leakage using the following formula.
The second method is to calculate out the percentage lost using a pressure gauge downstream from a receiver tank. This method requires one to know the total volume in the system to accurately estimate the leakage from the system. Once the compressor turns on wait until the system reaches the normal operating pressure for the process and record how long it takes to drop to a lower operating pressure of your choosing. Once this has been completed you can use the following formula to calculate out the total percentage of leakage.
The total percentage of the compressor that is lost should be under 10% if the system is properly maintained.
Once the total percentage of leakage has been calculated you can start to look at the cost of a single leak assuming that the leak is equivalent to a 1/16” diameter hole. This means that at 80 psig the leak is going to expel 3.8 SCFM. The average industrial air compressor can produce 4 SCFM using 1 horsepower of energy. Adding in the average energy cost of $0.25 per 1000 SCF generated one can calculate out the price per hour the leak is costing using the following calculation.
If you base the cost per year for a typical 8000 hr. of operating time per year you are looking at $480 per year for one 1/16” hole leak. As you can see the more leaks in the system the more costly it gets. If you know how much SCFM your system is consuming in leaks then that value can be plugged into the equitation instead of the assumed 3.8 SCFM.
If you’d like to discuss how EXAIR products can help identify and locate costly leaks in your compressed air system, please contact one of our application engineers at 800-903-9247.
Cody Biehle Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
A few weeks ago, we posted a blog discussing how artificial demand and leaks can lead to poor performance and expensive waste. Today, I’d like to review how following a few simple steps can help optimize your current compressed air system and reduce compressed air usage.
The first step you want to consider is measuring the air usage in the system. To do this, you want to start at the compressor and check individual leads to each drop point to a blowoff device, record your findings to track the demand. By measuring your compressed air usage, you can locate the source of high usage areas and monitor the usage on each leg of the system. If the demand exceeds the supply, there is potential for problems to arise, such as lowered pressure and force from compressed air operated devices leading to irregular performance.
EXAIR’s Digital Flowmeters are designed to measure flow continuously and accurately to give you real-time flow measurements of your compressed air system to help identify problems areas.
Step 2 is to locate the source of waste. Again, compressed air leaks can result in a waste of up to 30% of a facility’s compressor output. A compressed air leak detection and repair program can save a facility this wasted air. Implementing such a program can be used as a way for a facility to “find” additional air compressor capacity for new projects. Whenever a leak occurs, it will generate an ultrasonic noise.
Our Ultrasonic Leak Detector is designed to locate the source of ultrasonic sound emissions up to 20’ away. These ultrasonic sound emissions are converted to a range that can be heard by humans. The sound is 32 times lower in frequency than the sound being received, making the inaudible leaks, audible through the included headphones and the LED display gives a visual representation of the leak.
The 3rd step involves finding the source of noisy and wasteful blowoffs, like open pipes or homemade blowoffs, and replacing them with an energy efficient, engineered solution. By replacing these devices, you are not only reducing the amount of waste but also improving operator safety by complying with OSHA safety requirements.
EXAIR’s Digital Sound Level Meter is an easy to use instrument that measures and monitors the sound level pressure in a wide variety of industrial environments. The source of loud noises can be quickly identified so that corrective measures can be taken to keep sound levels at or below OSHA maximum allowable exposure limits.
The easiest way to reduce compressed air usage and save on operating expense is to turn off the compressed air to a device when it isn’t needed, step 4 in the process. Not only will this save money, in many cases, it can also simplify a process for the operator.
A simple manual ball valve and a responsible operator can provide savings at every opportunity to shut down the air flow.
For automated solutions, a solenoid valve can be operated from a machine’s control. For example, if the machine is off, or a conveyor has stopped – close the solenoid valve and save the air.
A foot pedal valve offers a hands free solution to activate an air operated device only when needed, such as being implemented in an operator’s work station.
For even more control, you can use a device like our EFC or Electronic Flow Control. This helps minimize compressed air usage by incorporating a programmable timing controlled (0.10 seconds to 120 hours) photoelectric sensor to turn off the compressed air supply when there are no parts present. It is suited for NEMA 4 environments and can be easily wired for 100-240VAC.
Step 5, intermediate storage. Some applications require an intermittent demand for a high volume of compressed air. By installing a receiver tank near the point of high demand, there is an additional supply of compressed air available for a short duration. This will help eliminate fluctuations in pressure and volume.
EXAIR offers a 60 gallon, ASME approved vertical steel tank with mounting feet for easy installation near high demand processes.
Many pneumatic product manufacturers have a certain set of specifications regarding performance at stated input pressures. In many applications, or in the case of using a homemade blowoff device like open pipe, these wouldn’t necessarily require the full rated performance of the device or full line pressure. Controlling the air pressure at the point-of-use device will help to minimize air consumption and waste, step 6.
By simply installing a pressure regulator on the supply side, you can start off at a low pressure setting and increase the pressure until the desired result is achieved. Not only will this help to conserve energy by only using the amount of air required for the application, it also allows you to fine tune the performance of the point-of-use device to match the application requirements.
If you have any questions, please contact an application engineer at 800-903-9247.
Almost every industry uses compressed air in some capacity. It is often referred to as the “fourth utility” In an industrial setting, next to water, gas and electric. and in many cases, is the largest energy user in the plant. With an average cost of $ 0.25 per every 1000 Standard Cubic Feet used, compressed air can be expensive to produce so it is very important to use this utility as efficiently as possible. When evaluating the performance of a compressed air system, it’s important to look at the system as a whole.
When you operate point-of-use devices at a higher pressure than necessary to perform a certain job or function, you are creating “artificial demand”. This results in excess air volume being consumed, increasing the amount of energy being lost to waste. For example, plant personnel or operators increase the supply pressure in an effort to improve the end use devices performance. When there is a leak in the system, the line pressure will actually begin to drop and performance begins to deteriorate in other areas in the plant. This not only puts stress on the existing compressor but it also leads to the false idea that a larger or secondary compressor is needed.
Here’s a quick reference on how operating pressure can directly affect operating cost:
Our Model # 1101 Super Air Nozzle requires 14 SCFM @ 80 PSIG. Based on the average operating cost of $ 0.25 per 1000 SCF used, it would cost $ 0.21 per hour to operate this nozzle. (14 SCFM x $ 0.25 x 60 minutes / 1000 SCF = $ 0.21)
If you were able to use the same Model # 1101 Super Air Nozzle operating at only 40 PSIG, while still achieving the desired end result, the air demand would decrease to only 8.1 SCFM, reducing the hourly cost to $ 0.12. (8.1 SCFM x $ 0.25 x 60 minute / 1000 SCF = $ 0.12)
Leaks in a compressed air system can account for up to 30% of the total operational cost of the compressor, wasting thousands of dollars of electricity per year. Some of the more common places for a leak to occur would be at connection points such as valves, unions, couplings, fittings, etc.
In this table, you will see that a certain amount of air volume is lost through an orifice or opening. If you have several leaks throughout your facility, it isn’t gong to take long for the waste and high operating costs to quickly add up as well as potential increases in repair or maintenance costs for the existing compressor. The industry average shows that any leakage more than 10%, shows there are areas where operational improvements could be made in a compressed air system.
Stay tuned to our blog over the next few weeks as we will discuss how following a few simple steps can help optimize your current compressed air system, in many cases, reducing energy costs related to compressed air waste, leading to a more economical operation.
In the meantime, if you have any questions or would like to discuss a particular application or EXAIR product, give me a call at 800-903-9247.
A few months ago, my counterpart Brian Bergmann wrote a blog providing a detailed explanation of ROI or Return on Investment. Today, I would like to take this information and apply it to a common situation we deal with regularly here at EXAIR – replacing drilled pipe with our Super Air Knife.
Sections of pipe with drilled holes across the length are very common as they are made of relatively inexpensive materials and simple to make. Where the cost begins to add up is on the operation side as these types of homemade blowoffs waste a ton of compressed air, making them expensive to operate.
For comparison, lets look at a 12″ section of pipe with (23) 1/16″ diameter drilled holes. According to the chart below, each hole will flow 3.8 SCFM @ 80 PSIG for a total of 87.4 SCFM.
With an average cost of $ 0.25 per every 1,000 SCF used (based on $ 0.08/kWh), it would cost $ 1.31 to operate this blowoff for 1 hour. (87.4 SCFM x 60 minutes x $ 0.25 / 1,000)
Now let’s take a look at replacing the drilled pipe with our 12″ Super Air Knife. A 12″ Super Air Knife will consume 34.8 SCFM (2.9 SCFM per inch) when operated at 80 PSIG. Using the same figure of $ 0.25 per every 1,000 SCF used, it would cost $ 0.52 / hr. to operate this knife. (34.8 SCFM x 60 minutes x $ 0.25 / 1,000)
Now that we know the operating costs, we can make a better comparison between the 2 products.
Drilled pipe operating costs: $ 1.31 per hour
$ 10.48 per day (8 hours)
12″ Super Air Knife costs: $ 0.52 per hour
$ 4.16 per day (8 hours)
$ 10.48 per day (drilled pipe) – $ 4.16 per day (Super Air Knife) = $ 6.32 savings per day
A 12″ aluminum Super Air Knife carries a LIST price of $ 297.00. If we take $ 297.00 divided by $ 6.32 (saving per day), we get a ROI of only 47 days.
As you can see, it is quite beneficial to consider ALL of the parameters when looking at a process or application, rather than just the “upfront” details. What seems like a simple and easy fix, can actually be quite wasteful when it comes to the true cost of ownership.
If you are using similar devices in your plant and would like to see how an EXAIR Intelligent Compressed Air Product can help make the process operate more efficiently, contact an application engineer for assistance.