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.
Many 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. Duke Energy, who supplies power to sections of North Carolina, South Carolina, Ohio, Kentucky, Indiana and Florida offers several “Smart $aver Rebates” that focus around the generation and use of compressed air. (State and Location Dependent)
Duke Energy’s Smart Saver Program
However the best place to look at your states available programs is the DSIRE database. DSIRE is the most comprehensive source of information on incentives and policies that support renewable energy and energy efficiency in the United States. Established in 1995, DSIRE is operated by the N.C. Clean Energy Technology Center at N.C. State University. Follow the link above to read about the history of DSIRE, the partners on the project, and the research staff that maintains the policy and incentive data in DSIRE.
Here you can see the two Programs that came up for 46077, you can then click the program name and it will take you a information page with the programs website and information!
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.
I had an application where a customer needed to have a room at 75% relative humidity (RH). They produced a nylon backing for carpet, and they needed the high RH to reduce the “stickiness” in the gluing process. Currently they were at 40% RH in a room that was measured at 40ft long by 20ft wide by 20ft high (12.2m long X 6.1m wide X 6.1m high). They wondered if our Atomizing Nozzles could help him to increase the relative humidity in the room. I decided to put on my engineering hat to calculate the amount of water that he would need to increase the humidity.
Relative humidity (RH) is the percentage of water vapor as compared to the saturation level at the same temperature. So, at 100% RH, the ambient air is saturated and cannot hold any more water vapor. You can feel the difference in the Amazon versus Arizona at the same temperature. With dryer conditions, water can be added to increase the relative humidity; like a humidifier. With the EXAIR Atomizing Nozzles, we can break liquid water into very small droplets to help increase the humidification rate. For the customer above, I will have to determine what size and how many Atomizing Nozzles are required.
Equation 1
H = V * ACH * (Wf – Wi) / (v * 7000)
Where:
H – mass flow rate of water, Lbs/hr
V – Volume of room, ft3
ACH – Air changes per hour
Wf – Final Water Content, Grains/lb of dry air
Wi – Initial Water Content, Grains/lb of dry air
v – Specific Volume of Air, ft3/lb
Conversion Constant – 7000 Grains/lb
The customer stated that the room was set to 68oF (20oC), and they used an air handling unit (AHU) that produced 1,600 cfm (44.5 M3/min) of air into the room. From these factors, we can determine some of the variables above. For the Air Changes per Hour (ACH), we can use Equation 2.
Equation 2
ACH = 60 * Q / V
Where:
ACH – Air changes per hour
Q – Volumetric flow rate, CFM
V – Volume of room, ft3
The volume of the room is V = 40ft X 20ft X 20ft = 16,000 ft3. The volumetric flow rate by the AHU is 1,600 ft3/min. From Equation 2,
ACH = 60 * (1600 ft3/min) / 16,000 ft3
ACH = 6/hr.
In determining the water content values, you can find a chart online to determine the amount of water vapor that is contained in the air at a specific temperature and RH. At 68oF (20oC), I was able to find the following information:
Wi = 40.58 Grains/lb of dry air at 40% RH
Wf = 76.71 Grains/lb of dry air at 75% RH
v = 14.286 ft3/lb @ 68 deg. F, 1 atm
V = 16,000 ft3
If we plug in the numbers that we have into Equation 1, we can determine how much water that we will need to spray into the air to increase the RH from 40% to 75%.
With my prior line of work in room humidification, we know that there is a lead/lag time between measuring and humidifying. This may seem complicated, but it is important to get a steady state condition for the Relative Humidity. To help this customer, I recommend a cycle time of 15 second to turn on and wait 105 seconds to re-measure the RH. This will help to not over-saturate the room. As for the location of the Atomizing Nozzles, we want to be near the ceiling to get the most “air” time to vaporize. We also have to be careful to not allow the water spray to hit any objects or each other as this will cause the water to condense.
To start, I suggested our model AT2010SS No Drip Internal Mix 360o Hollow Circular Pattern. This type of nozzle helps to extend the settling time of the water droplets; the amount of time that the droplets are suspended in the air. The orientation of the spray is outward in all direction to increase coverage. With the No Drip option, it is controlled by the air pressure to open and close the liquid side for spraying. When the compressed air is turned off, a valve will seal the liquid side to not allow any drips. It also helps to eliminate the need for any liquid valves next to the Atomizing Nozzles. When it comes to cycle spraying, the No Drip option works wonderful.
In taking into consideration the flow rate required during operation time, we can calculate the amount of liquid flow required for the Atomizing Nozzle in Equation 3.
Equation 3:
Flow rate: Q = H / (D * T * f)
Where:
Q – Liquid flow rate (gal/hr or GPH)
H – Mass Flow Rate (lbs/hr)
D – Density of Water (8.34 lbs/gal)
T – Span division (no scale)
f – Intermittent Factor (no scale)
To determine the number of Atomizing Nozzles, we want to look at the time determination with the controller and the intermittence of operation. With the ACH = 6/hour, the air in the room will change over every 10 minutes. We want to have a balance between the new air and the existing air. So, with the time measurement of 15 seconds on and 105 seconds off (2 minutes), we will have 5 humidity checks over the 10 minutes. We can divide the amount of water to be injected into the room by the span division, T, to cover the time span for check and atomization. Thus, T = 5. We will also have to adjust the amount for only running 15 second intervals. So, the intermittent factor, f, will be 0.0042 (the 15 seconds portion of the hour).
With these values, we get:
Q = (34.68 lbs/hr) / (8.34 lbs/gal * 5 * 0.0042)
Q = 198 gal/hr (GPH)
In the catalog, the model AT2010SS will flow 14.7 GPH (55.7 LPH) of water at 60 PSIG (4.1 Bar) liquid pressure. If we divide these out, it will tell us how many atomizing nozzles that is needed to humidify the room.
Number of Nozzles: 198 GPH/14.7 GPH = 13.5 or 14 Atomizing Nozzles.
With the above Atomizing Nozzles, the company was able to control the RH at a high level for his manufacturing process. In turn, he was able to increase productivity and reduce downtime. If you need to increase the level of humidity in your area, you can contact an Application Engineer at EXAIR for help. We can make it feel like the Amazon.
Naturally, spring is the time of year that we roll up our sleeves and do some of the deep-cleaning we’ve been putting off all winter. Lucky for you, EXAIR has an entire line of Industrial Housekeeping Products that’ll get your shop cleaned up for spring. With no moving parts to wear out and no electrical requirement, these products are Built to Last. For applications requiring you to vacuum very fine or dusty materials, look no further than EXAIR’s Heavy Duty HEPA Vac.
Electrically powered vacuums or shop vacs are not designed to be operated in a rugged industrial environment. Filters clog, motors wear out, and you find yourself frequently replacing them. EXAIR’s Heavy Duty HEPA Vac has NO moving parts to wear out, doesn’t require maintenance, and needs nothing but a source of compressed air to operate. A static resistant hose also prevents painful shocks when working with dry, dusty materials.
The vacuum generator is constructed of a hardened steel alloy designed to be resistant to abrasion and delivers a powerful vacuum level of -60” H2O at 80 PSIG. The lever lock drum lid fits any open top 30, 55, or 110 gallon drum. Moving the system from one drum to another can be done quickly, allowing you to keep different materials separate for recycling. Recycling companies will pay a premium for pre-sorted materials, allowing you to get more out of your otherwise scrap material. It can be used with any open head steel, fiber, or plastic drum in good condition (ANSI Standard #MH2-2004).
If you don’t have a spare drum available, not to worry! EXAIR also sells a Premium Heavy Duty HEPA Vac System that will include either a 30, 55, or 110 gallon drum and dolly.
The HEPA Vac works by injecting compressed air at 80-100 PSIG through the air inlet (1) and into an annular plenum chamber (2). It is then injected into the throat through precisely directed nozzles (3). These jets of air create a vacuum at the intake (4) which draws in material through the generator itself (5), directing it into the bottom of the drum. The airflow is passed first through a pre-filter to trap larger particles, and then through the 0.3 micron HEPA filter, trapping any airborne particles. It is then exhausted through the vent in the top of the drum lid (6).
You wouldn’t use a hammer to try and drive in a screw, so don’t try and force a shop vac or electric vacuum to deal with these harsh materials. Get yourself the right tool for the job and give an EXAIR Vac a try. With a 5 Year Built to Last Warranty, there really is no comparison. Act fast, between now and April 30, 2022 we’ll include a FREE Model 6492 Vac-u-Gun System to any US and Canadian order.
The use of compressed air in industry is so widespread that it’s long been called “the fourth utility” (along with electricity, water, and natural gas). As a function of energy consumption (running an air compressor) to energy generated (operation of pneumatic equipment), only 10-15% of the energy consumed is converted to usable energy stored as compressed air. Its “bang for the buck”, however, comes when you consider the total cost of ownership – yes, it costs a lot to generate, but:
It’s relatively safe, when compared to the risks of electrocution, combustion, and explosion associated with electricity & natural gas.
Air operated tools, equipment, and products are generally much cheaper than their electric, gas, or hydraulic powered counterparts.
Air operated products, like anything, require periodic maintenance, but oftentimes, that maintenance simply comes down to keeping the air supply clean and moisture free, unlike the extensive (and expensive) maintenance requirements of other industrial machinery.
Even with these advantages, though, it’s still critical to get all you can out of that 10-15% of the energy you’re consuming to make that compressed air, and that starts with having the right stuff in the right place. Now, all of the following “stuff” might not apply to every compressed air system. I once worked in a repair shop, for example, with a small compressor that was used for a couple of blow off guns, impact drivers, and a sidearm grinder. I’ve also done field service in facilities with hundreds of pneumatic cylinders & air motors that operated their machinery. Those places had even more “stuff” than I’m devoting space to in this blog, but here’s a list of the “usual suspects” that you’ll encounter in a properly designed compressed air system:
Air compressor. I mean, of course you need a compressor, but the size and type will be determined by how you’re going to use your air. The small repair shop I worked in had a 5HP reciprocating positive displacement compressor with a 50 gallon tank, and that was fine. The larger facilities I visited often had several 100 + HP dynamic centrifugal or axial compressors, which get more efficient with size.
Air preparation. This includes a number of components that can be used to cool, clean, and dry the air your compressor is generating:
Pressurizing a gas raises its temperature as well. Hot compressed air could cause unsafe surface temperatures and can damage gaskets, seals, and other components in the system. Smaller compressors might not have this problem, as the heat of compression is often dissipated through the wall of the receiver tank and the piping at a rate sufficient to keep the relatively low (and often intermittent) flow at a reasonable temperature. Larger compressors usually come with an aftercooler.
The air you compress likely has a certain amount of moisture in it…after nitrogen and oxygen, water vapor usually makes up more of the content of atmospheric air than all other trace gases combined. There are a number of air dryer types; selection will be dictated by the specifics of your facility.
Your air is going to have other contaminants in it too. We did welding & grinding in the repair shop where our compressor sat in the corner. We kept a few spare intake filters handy, and replaced them regularly. In conjunction with the aftercooler & dryer, larger industrial compressors will also have particulate filters for these solids. For extra protection, coalescing filters for oil vapor, and adsorption filters for other gases & liquid vapors, are specified.
Distribution. In the repair shop, we had a 3/4″ black iron pipe that ran across the ceiling, with a few tees & piping that brought the air down to the individual stations where we used it. The larger facilities I visited had larger variations of this “trunk and branch” type network, and some were even big enough to make use of a loop layout…these were especially popular when multiple air compressors were located throughout the facility. In addition to black iron, copper & aluminum pipe (but NEVER PVC) are commonly used too.
Condensate removal. The small repair shop compressor had a valve on the bottom of the tank with a small hose that we’d blow down into a plastic jug periodically. Larger systems will have more complex, and oftentimes automated condensate management systems.
So, that’s the system-wide “stuff” you’ll usually encounter in a properly designed compressed air system. After that, we’ll find a number of point-of-use components:
Air preparation, part 2. The compressor intake & discharge filtration mentioned above make sure that you’re putting clean air in the distribution piping. That’s fine if your distribution piping is corrosion resistant, like aluminum or copper, but black iron WILL corrode, and that’s why you need point-of-use filters. EXAIR Automatic Drain Filter Separators have 5 micron particulate elements, and centrifugal elements that ‘spin’ any moisture out. If oil is an issue, our Oil Removal Filters have coalescing elements for oil/oil vapor removal, and they provide additional particulate protection to 0.03 microns.
Pressure control. Your compressor’s discharge pressure needs to be high enough to operate your pneumatic device(s) with the highest pressure demand. Odds are, though, that not everything in your plant needs to be operated at that pressure. EXAIR Pressure Regulators are a quick & easy way to ‘dial in’ the precise supply pressure needed for specific products so they can get the job done, without wasting compressed air.
Storage. This could also be considered system “stuff”, but I’m including it under point-of-use because that’s oftentimes the reason for intermediate storage. Having a ready supply of compressed air near an intermittent and/or large consumption device can ensure proper operation of that device, as well as others in the system that might be “robbed” when that device is actuated. They’re good for the system, too, as they can eliminate the need for higher header pressures, which cause higher operating costs, and increased potential for leaks. EXAIR Model 9500-60 60 Gallon Receiver Tanks are an ideal solution for these situations.
For more information on proper installation and use of compressed air system “stuff” like this, the Compressed Air & Gas Institute’s Compressed Air and Gas Handbook has a good deal of detailed information. The Air Data section of EXAIR’s own Knowledge Base is a great resource as well.
Of course, all the attention you can pay to efficiency on the supply side doesn’t matter near as much if you’re not paying attention to HOW you’re using your compressed air. EXAIR Intelligent Compressed Air Products are designed with efficiency, safety, and noise reduction in mind. Among the other ways my fellow Application Engineers and I can help you get the most out of your compressed air system, we’re also here to make sure you get the right products for your job. To find out more, give me a call.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
