Return on Investment (ROI) is a measure of the gain (preferably) or loss generated relative to the amount of money that was invested. ROI is typically expressed as a percentage and is generally used for financial decisions, examining the profitability of a company, or comparing different investments. It can also be used to evaluate a project or process improvement to decide whether spending money on a project makes sense. The formula is shown below-
A negative ROI says the project would result in an overall loss of money
An ROI at zero is neither a loss or gain scenario
A positive ROI is a beneficial result, and the larger the value the greater the gain
Example – installing a Super Air Nozzles (14 SCFM compressed air consumption) in place of 1/4″ open pipe (33 SCFM of air consumption consumption) . Using the Cost Savings Calculator on the EXAIR website, model 1100 nozzle will save $1,710 in energy costs. The model 1100 nozzle costs $42, assuming a $5 compression fitting and $45 in labor to install, the result is a Cost of Investment of $92.00. The ROI calculation for Year one is-
ROI = 1,759% – a very large and positive value. Payback time is only 13 working days!
If you have questions regarding ROI and need help in determining the gain and cost from invest values for a project that includes an EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
Recently I worked with a customer on an application to remove contaminants from the inside of glass bottles. During production, dust from the ambient environment was collecting inside of the bottles. They needed a way to remove it prior to filling. The solution was to briefly pause the conveyor, pulsing air into the bottles to free any dust that had accumulated. Their problem was that while the dust was blowing out of the bottle without an issue, some of it was settling back down into the bottles.
The customer needed a way to mitigate the risk of dust particles resettling into the bottles after it was removed. The solution was to install a Model 2012 12” Standard Air Knife to provide a curtain of air across the top of the bottles, catching any freed dust particles and blowing them away from the conveyor.
After noticing positive results, we wanted to take things one step further and help to reduce overall air consumption in the process. The blowoff was achieved with (8) ¼” open tubes operating at a pressure of 80 PSIG. Although they were only operating for a fraction of a second, they still consume a whopping 33 SCFM! Replacing them with Model 1101 ¼” NPT Super Air Nozzles (14 SCFM at 80 PSIG) resulted in compressed air savings of 58%!!
In addition to saving compressed air, the noise level was also dramatically reduced. At just 74 dBA, we’re below the threshold for an 8-hour exposure time for operators according to OSHA. Where earplugs were necessary before, they’re now able to operate safely without the need for PPE to protect their hearing. The second most effective fundamental method of protecting workers, according to NIOSH, is to substitute or replace the hazard with an engineered solution. It’s not possible to eliminate the hazard as a compressed air blowoff was necessary, but the next best step is to replace it with something safer.
In addition to complying with OSHA 1910.95(a), the Super Air Nozzle also cannot be dead-ended. In applications for compressed air blowoff with unsafe nozzles, pipes, or tubes, the pressure must be regulated down to below 30 PSIG according to OSHA 1910.242(b). The installation of an engineered compressed air nozzle by EXAIR allows you to operate safely at much higher pressures.
If you have inefficient blowoff processes in your facility, give one of our Application Engineers a call. We’ll be happy to take a closer look at your application and recommend a safe, reliable, engineered solution!
Take a second and think about where the air compressor is located within your facility. It is more than likely not a major focal point displayed prominently in the floor layout. There is a better chance it is tucked away in a corner of the facility where operators seldom travel. No matter the type of air compressor, it still has an intake where it pulls in the ambient air from around the compressor then sends it through some process and on the demand side of your compressed air system. These intakes can easily be placed out of sight and out of mind especially in older facilities that were designed when compressors were loud and the piping layout kept them away from operators due to sound level restrictions.
That’s why your compressor manufacturer supplies a specific grade of air inlet/intake filter, and this is your first line of defense. If it’s dirty, your compressor is running harder, and costs you more to operate it. If it’s damaged, you’re not only letting dirt into your system; you’re letting it foul & damage your compressor. It’s just like changing the air filter on your car, your car needs clean air to run correctly, so does your compressor and the entire demand side of your compressed air system.
According to the Compressed Air Challenge, as a compressor inlet filter becomes dirty, the pressure drop across the inlet increases, this is very similar to the point of use compressed air filters. The inlet filter on the compressor is the only path the compressor has to pull in the air, when restricted the compressor can begin to starve for air very similar to if you only had a small straw to breath through and told to run a marathon. A clogged inlet filter can give false symptoms to compressor technicians as well.
The effects can mimic inlet valve modulation which result in increased compression ratios. If we were to form an example based on a compressor with a positive displacement, if the filter pressure drop increases by 20″ H2O, a 5% reduction of the mass flow of air will be present without a reduction in the power being drawn by the compressor. This all leads to inefficiency which easily amounts to more than the cost to replace the depleted inlet air filter.
Where you place the filter is just as important as how often you replace it. There are some tips to be used when mounting the inlet filter.
The filter can be placed on the compressor, but the inlet pipe should be coming from an external area to the compressor room or even the building if possible. The inlet should be free from any contaminants as well. Some examples that are easy to overlook are nearby condensate discharges, other system exhausts and precipitation.
Depending on the type of compressor being used, a lower intake air temperature can increase the mass flow of air due to the air density. A compressor that is lubricant injected is not susceptible to this due to the air mixing with the warmer lubricant before being compressed.
If you would like to discuss improving your compressed air efficiency or any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.
It is important to know the cost of compressed air at your facility. Most people think that compressed air is free, but it is most certainly not. Because of the expense, compressed air is considered to be a fourth utility in manufacturing plants. In this blog, I will show you how to calculate the cost to make compressed air. Then you can use this information to determine the need for Intelligent Compressed Air® products.
There are two types of air compressors, positive displacement and dynamic. The core construction for both is an electric motor that spins a shaft. Positive displacement types use the energy from the motor and the shaft to change the volume in an area, like a piston in a reciprocating compressor or like rotors in a rotary compressor. The dynamic types use the energy from the motor and the shaft to create a velocity energy with an impeller. (You can read more about air compressors HERE). For electric motors, the power is described either in kilowatts (KW) or horsepower (hp). As a unit of conversion, there are 0.746 KW in 1 hp. The electric companies charge at a rate of kilowatt-hour (KWh). So, we can determine the energy cost to spin the electric motors. If your air compressor has a unit of horsepower, or hp, you can use Equation 1:
hp * 0.746 * hours * rate / (motor efficiency)
hp – horsepower of motor
0.746 – conversion to KW
hours – running time
rate – cost for electricity, KWh
motor efficiency – average for an electric motor is 95%.
If the air compressor motor is rated in kilowatts, or KW, then the above equation can become a little simpler, as seen in Equation 2:
KW * hours * rate / (motor efficiency)
KW – Kilowatts of motor
hours – running time
rate – cost for electricity, KWh
motor efficiency – average for an electric motor is 95%.
As an example, a manufacturing plant operates 250 day a year with 8-hour shifts. The cycle time for the air compressor is roughly 50% on and off. To calculate the hours of running time, we have 250 days at 8 hours/day with a 50% duty cycle, or 250 * 8 * 0.50 = 1,000 hours of running per year. The air compressor that they have is a 100 hp rotary screw. The electrical rate for this facility is at $0.08/KWh. With these factors, the annual cost can be calculated by Equation 1:
In both equations, you can substitute your information to see what you actually pay to make compressed air each year at your facility.
The type of air compressor can help in the amount of compressed air that can be produced by the electric motor. Generally, the production rate can be expressed in different ways, but I like to use cubic feet per minute per horsepower, or CFM/hp.
The positive displacement types have different values depending on how efficient the design. For a single-acting piston type air compressor, the amount of air is between 3.1 to 3.3 CFM/hp. So, if you have a 10 hp single-acting piston, you can produce between 31 to 33 CFM of compressed air. For a 10 hp double-acting piston type, it can produce roughly 4.7 to 5.0 CFM/hp. As you can see, the double-acting air compressor can produce more compressed air at the same horsepower.
The rotary screws are roughly 3.4 to 4.1 CFM/hp. While the dynamic type of air compressor is roughly 3.7 – 4.7 CFM/hr. If you know the type of air compressor that you have, you can calculate the amount of compressed air that you can produce per horsepower. As an average, EXAIR uses 4 CFM/hp of air compressor when speaking with customers who would like to know the general output of their compressor.
With this information, we can estimate the total cost to make compressed air as shown in Equation 3:
C = 1000 * Rate * 0.746 / (PR * 60)
C – Cost of compressed air ($ per 1000 cubic feet)
1000 – Scalar
Rate – cost of electricity (KWh)
0.746 – conversion hp to KW
PR – Production Rate (CFM/hp)
60 – conversion from minutes to hour
So, if we look at the average of 4 CFM/hp and an average electrical rate of $0.08/KWh, we can use Equation 3 to determine the average cost to make 1000 cubic feet of air.
Once you have established a cost for compressed air, then you can determine which areas to start saving money. One of the worst culprits for inefficient air use is open pipe blow-offs. This would include cheap air guns, drilled holes in pipes, and tubes. These are very inefficient for compressed air and can cost you a lot of money. I will share a comparison to a 1/8” NPT pipe to an EXAIR Mini Super Air Nozzle. (Reference below). As you can see, by just adding the EXAIR nozzle to the end of the pipe, the company was able to save $1,872 per year. That is some real savings.
Making compressed air is expensive, so why would you not use it as efficiently as you can. With the equations above, you can calculate how much you are paying. You can use this information to make informed decisions and to find the “low hanging fruit” for cost savings. As in the example above, targeting the blow-off systems in a facility is a fast and easy way to save money. If you need any help to try and find a way to be more efficient with your compressed air system, please contact an Application Engineer at EXAIR. We will be happy to assist you.