The use of compressed air can be found in almost any industry and is often referred to as a “fourth utility” next to water, gas and electric. The generation of compressed air accounts for approximately 1/3 of all energy costs in an industrial facility, in many cases, it’s the largest energy user in an industrial plant. With an average cost of $ 0.25 per every 1,000 SCF used, compressed air can be expensive to produce so it is very important to use this utility as efficiently as possible.
Utility companies recognize the benefit of using engineered products to reduce compressed air usage, like the ones manufactured by EXAIR, and offers rebate incentives for making a switch. Our local utility provider here in Cincinnati, Duke Energy, offers a $ 20 incentive for each replacement engineered nozzle.
In their specification, the nozzle must meet a certain volumetric flow rate (SCFM) at 80 PSIG operating pressure for a given pipe size. For example, when looking at a 1/4″ nozzle, the flow rate must be less than or equal to 17 SCFM when operated at 80 PSIG. Our most popular nozzles for “general” blowoff applications would be our Model # 1100 (1/4″ FNPT) or our Model # 1101 (1/4″ MNPT) Super Air Nozzles. These nozzles require 14 SCFM @ 80 PSIG so this would be the ideal solution to reduce the air demand and take advantage of the rebate.
Here at EXAIR, much of our focus is to improve the overall efficiency of industrial compressed air operating processes and point of use compressed air operated products. If you’d like to contact one of our application engineers, we can help recommend the proper engineered solution to not only save on your compressed air usage but also assist with possible energy rebates available in your area.
One common thing that can be easily overlooked is the importance of designing an efficient compressor room. After you’ve determined your overall requirements and selected the appropriate compressor, you can begin designing the layout of your compressor room. For starters, the compressor room should be located in a central location when possible, close to the point of use. This will help to minimize pressure drop as well as reduce installation costs as less piping will be required. If this isn’t possible, try to keep the compressor room close to the larger volume applications in your facility. Otherwise you will have to use larger diameter piping in order to ensure an adequate volume of air is available.
The diameter of the distribution piping should NOT be based on the connection size of the compressors, aftercoolers, or filters. According to the Compressed Air ChallengeBest Practices for Compressed Air Systems handbook, piping should be sized so that the maximum velocity in the pipe is 30 ft/sec. When the distance between the compressor room and the point of use is lengthy, consider increasing the pipe diameter to minimize the pressure drop across the system.
Inside of your compressor room you’ll have a variety of different equipment, all dependent on the demand, quality, supply, storage, and distribution of your compressed air. Keeping all of the equipment in its own room will also provide some insulation from the noise associated with compressed air generation. It is crucial that the space selected as your compressor room is sufficiently large enough to accommodate everything without becoming cramped. As a general rule of thumb, keep about 3′ of space between equipment such as the compressor, receiver tanks, aftercooler, and dryer. This helps to prevent equipment from overheating as well as offers maintenance personnel adequate space with which to perform any regularly scheduled maintenance or repairs.
Once you’ve selected your equipment, piping, and determined the location, another thing to consider is ventilation. As compressed air is generated, the compressor gives off a good amount of heat. It is important that the exhaust air is not permitted to re-circulate throughout the compressor room. The exhaust needs to be ducted so that it the warm air is not drawn in at the air intake on the compressor. Some equipment, such as refrigerated dryers, requires a substantial amount of cooling air. In these situations, an exhaust fan can be used to provide that additional airflow.
To further enhance the efficiency of your facility, the heat generated from compression can be re-purposed instead of simply exhausting into the ambient environment. This process is commonly referred to as compressed air energy recovery. Some industries require a source of heat for many of their manufacturing processes. In these scenarios, the heat energy that is produced during compression can be reused rather than having to generate another source of heated air. If the heated air can’t be used for any of your manufacturing processes, the heat can be used as a means to heat your water supply or even to heat the facility itself. This can drastically reduce your electricity or gas requirements during cooler periods.
To reduce the amount of required maintenance and ensure that your compressor is operating as efficiently as possible, the compressed air intake must also be free from particulate and harmful gases. When dust and dirt is drawn into the compressor, it can cause wear on the internal components. If the ambient environment contains a lot of dust and particulate, a pre-filter can be used to prevent any future problems. In these instances, it is important to consider the pressure drop that will be caused when designing the system.
Keeping these tips in mind will serve to make your life much easier in the long run. Once you have everything installed and set up, visit the EXAIR website or give us a call to speak with an Application Engineer. EXAIR’s Intelligent Compressed Air Products can help you reduce compressed air consumption and increase worker safety by adhering to both OSHA 1910.242(b) and 1910.95.
The Digital Flowmeter is available from stock for use on Schedule 40 pipe with sizes ranging from ½”-4” I.D. Sizes up to 6” for Schedule 40 and ¾”-4” for copper pipe are also available. With a digital readout display, it’s easy to accurately monitor your compressed air usage throughout the facility. Creating a baseline of your usage will allow you to understand your compressed air demand, identify costly leaks, and replace inefficient air products.
The Digital Flowmeter installs in minutes with help from a drill guide and locating fixture to assist in mounting the Digital Flowmeter to the pipe. Two flow sensing probes are inserted into the drilled holes in the pipe. The meter then seals to the pipe once tightened. There is no need to cut, weld, or do any calibration once it is installed. With blocking rings also available, installation can be permanent or temporary.
The newest addition to this product line is the Digital Flowmeter with wireless capability. Using a ZigBee® mesh network protocol, data is transmitted to an Ethernet connected gateway. This allows you to mount the Digital Flowmeter in areas that you may not be able to easily access and wirelessly monitor and graph the usage with the EXAIR Logger software. Take a peek at this video blog for a demonstration of the use of a wireless Digital Flowmeter software to compare an open pipe to an engineered Air Nozzle.
In addition to communicating wirelessly with the gateway, the Digital Flowmeters can “piggyback” off of each other to extend their range. Each meter has a range of 100’. Using multiple Digital Flowmeters within the same ZigBee® mesh network, data can be passed from meter to meter to extend the distance over which the meters can operate. These can be installed on each major leg of your compressed air system to continuously monitor usage throughout the facility.
If you’d rather go with a hard-wired data collection method, the Digital Flowmeter is also available with a USB Data Logger. Simply remove the Data Logger from the Digital Flowmeter and connect it to the USB port of your computer. The data can then be viewed directly in the accompanying software or exported into Microsoft Excel.
If you’d like to get a clear view of your compressed air usage, give us a call. An Application Engineer will be happy to work with you and get the proper Digital Flowmeters installed in your facility!
On November 2, 2017 at 2 PM EDT, EXAIR Corporation will be hosting a FREE webinar titled “Optimizing Your Compressed Air System In 6 Simple Steps”.
During this short presentation, we will explain the average cost of compressed air and why it’s important to evaluate the current system. Compressed air can be expensive to produce and in many cases the compressor is the largest energy user in a plant, accounting for up to 1/3 of the total energy operating costs. In industrial settings, compressed air is often referred to as a “fourth utility” next to water, gas and electric.
Next we will show how artificial demand, through operating pressure and leaks, can account for roughly 30% of the air being lost in a system, negatively affecting a company’s bottom line. We will provide examples on how to estimate the amount of leakage in a system and ways to track the demand from point-of-use devices, to help identify areas where improvements can be made.
To close, we will demonstrate how following six simple steps can save you money by reducing compressed air use, increasing safety and making your process more efficient.
My colleague, Lee Evans, wrote a blog “About Single Acting Reciprocating Compressors”, and I wanted to extend that conversation to a more efficient relative, the double acting reciprocating compressor. As you see in the chart below, this type of compressor falls within the same family under the category of positive displacement compressors.
Positive displacement compressors increase air pressure by reducing air volume within a confined space. The reciprocating type of air compressor uses a motor that turns a crank which pushes a piston inside a cylinder; like the engine in your car. In a basic cycle, an intake valve opens to allow the ambient air into the cylinder, the gas gets trapped, and once it is compressed by the piston, the exhaust valve opens to discharge the compressed volume into a tank. This method of compression happens for both the single and double acting reciprocating compressors. With a single acting compressor, the air is compressed only on the up-stroke of the piston inside the cylinder. The double acting compressor compresses the air on both the up-stroke and the down-stroke of the piston, doubling the capacity of a given cylinder size. This “double” compression cycle is what makes this type of air compressor very efficient. A single acting compressor will have an operating efficiency between 22 – 24 kW/100 cfm of air while the double acting compressor has an operating efficiency between 15 – 16 kW/100 cfm. Therefore, electricity cost is less with a double-acting reciprocating air compressor to make the same amount of compressed air.
To explore the internals a bit closer, the mechanical linkage used to move the piston is slightly different as well as the additional intake and exhaust valves. Instead of the connecting rod being attached directly to the piston as seen inside a single acting compressor, a crosshead is added between the compression piston and the connecting rod (view picture below). The rod that connects the crosshead to the compression piston can be sealed to keep the cylinder completely encapsulated. For every rotation of the electric motor, the air is being compressed twice. With the added heat of compression, the double acting compressors are generally water-cooled. Also, with the added mechanism between the crank and the piston, the rotational speeds are typically less. Because of the larger size, water jackets, and added parts, the initial cost is more expensive than the single acting compressor, but the efficiency is much higher.
Double acting compressors are generally designed for rugged 100% continuous operations. Dubbed the work horse of the compressor family, they are also known for their long service life. They are commonly used in high pressure services in multistage styles and can come in lubricated and non-lubricated configurations. With the dual compression, slow speed and inter-cooling, it makes this type of air compressor very proficient in making compressed air.
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 personal 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
Gain from investment could include many factors, such as energy savings, reduced scrap savings, cost per part due to increased throughput savings, and many more. It is important to analyze the full impact and to truly understand all of the savings that can be realized.
Cost of investment also could have many factors, including the capital cost, installation costs, downtime cost for installation, and others. The same care should be taken to fully capture the cost of the investment.
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 $37, assuming a $5 compression fitting and $50 in labor to install, the result is a Cost of Investment of $92.00. The ROI calculation for Year 1 is-
ROI = 1,759% – a very large and positive value. Payback time is only 13 working days.
Armed with the knowledge of a high ROI, it should be easier to get projects approved and funded. Not proceeding with the project costs more than implementing it.
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.
No one likes paying their bills at the end of the month. But, if you can save yourself some money, it helps to make it a little easier. For this customer, he received a monthly bill for his compressed air.
An industrial facility consisting of four separate manufacturing plants and a power company that supplied all of them with utilities, i.e. hot water, natural gas, electricity, and compressed air. The parent company decided to reorganize and sell the entities. At the end of it, the power company was controlled by a different organization than the manufacturing plants. The power plant was contracted to still supply the utilities to the individual plants, but now they would be charged individually on a monthly basis.
Being that compressed air is one of the most expensive utilities, the general manager of a solid-state electronic plant really noticed the charge on his bill. He did an estimate on the amount of air that his equipment was using, and he compared it to the charges. There was roughly a 20% difference in the figures. Because of the excessive amount of money, he contacted EXAIR to see what we could offer.
In discussing their system, the compressed air was supplied through one 6” schedule 40 black pipe. The pipe came into the facility in the ceiling and it branched off to supply the entire shop with compressed air. He was looking for something to measure the compressed air flow with the ability to measure a cumulative amount. He could use this amount to compare to his monthly usage. He was also concerned about cutting into his compressed air line as this could cause him much downtime and additional costs. He needed something easy to install, accurate, and versatile.
I suggested our 6” Digital Flowmeter with the Model 9150 Summing Remote Display. EXAIR Digital Flowmeters are designed to measure flow continuously and accurately. You do not need to weld, cut, or disassemble pipe lines to install. With a drill guide, the Digital Flowmeter can be easily mounted onto the 6” black pipe by drilling two small holes. After that, they just had to insert the Digital Flowmeter into the holes, and tighten the clamp around the pipe. The total procedure took less than 30 minutes, so downtime was minimal. The EXAIR Digital Flowmeter measures flow by comparative analysis with thermal dispersion; so, the accuracy is very high and recalibration is not required.
With the option of the Summing Remote Display, they could attach it to the Digital Flowmeter and display the flow remotely up to 50 feet away. They mounted it on the wall next to his office for the operational functions. With a simple press of a button, it can show the current flow rates, daily flow rates, and cumulative flow rates. So, during the billing cycle, he was able to get the cumulative measurement to compare the results, and reset the counter to zero for the next month.
Believe it or not, the power company was correct in their measurements. But, not to waste an entire blog, I did have him turn the compressed air supply off after business hours to watch the flow rate. He did find his 20% difference in compressed air leakage. The Digital Flowmeter was able to measure low flows to target other problem areas in your compressed air system. Now he had another chore in leak detecting and pipe fixing.
EXAIR Optimization line has different products that can help you to get the most out of your compressed air system. With the customer above, he was able to measure his compressed air flow with the Digital Flowmeter, as well as detecting other issues. I will now have to talk to him about our Ultrasonic Leak Detector.