Estimating the Cost of Compressed Air Systems Leaks

Leaks in a compressed air system can waste thousands of dollars of electricity per year. In fact, in many plants, the leakage can account for up to 30% of the total operational cost of the compressor. Some of the most common areas where you might find a leak would be at connection joints like valves, unions, couplings, fittings, etc. This not only wastes energy but it can also cause the compressed air system to lose pressure which reduces the end use product’s performance, like an air operated actuator being unable to close a valve, for instance.

One way to estimate how much leakage a system has is to turn off all of the point-of-use devices / pneumatic tools, then start the compressor and record the average time it takes for the compressor to cycle on and off. The total percentage of leakage can be calculated as follows:

Percentage = [(T x 100) / (T + t)]

T = on time in minutes
t = off time in minutes

The percentage of compressor capacity that is lost should be under 10% for a system that is properly maintained.

Another method to calculate the amount of leakage in a system is by using a downstream pressure gauge from a receiver tank. You would need to know the total volume in the system at this point though to accurately estimate the leakage. As the compressor starts to cycle on,  you want to allow the system to reach the nominal operating pressure for the process and record the length of time it takes for the pressure to drop to a lower level. As stated above, any leakage more than 10% shows that improvements could be made in the system.

Formula:

(V x (P1 – P2) / T x 14.7) x 1.25

V= Volumetric Flow (CFM)
P1 = Operating Pressure (PSIG)
P2 =  Lower Pressure (PSIG)
T = Time (minutes)
14.7 = Atmospheric Pressure
1.25 = correction factor to figure the amount of leakage as the pressure drops in the system

Now that we’ve covered how to estimate the amount of leakage there might be in a system, we can now look at the cost of a leak. For this example, we will consider a leak point to be the equivalent to a 1/16″ diameter hole.

A 1/16″ diameter hole is going to flow close to 3.8 SCFM @ 80 PSIG supply pressure. An industrial sized air compressor uses about 1 horsepower of energy to make roughly 4 SCFM of compressed air. Many plants know their actual energy costs but if not, a reasonable average to use is $0.25/1,000 SCF generated.

Calculation :

3.8 SCFM (consumed) x 60 minutes x $ 0.25 divided by 1,000 SCF

= $ 0.06 per hour
= $ 0.48 per 8 hour work shift
= $ 2.40 per 5-day work week
= $ 124.80 per year (based on 52 weeks)

As you can see, that’s a lot of money and energy being lost to just one small leak. More than likely, this wouldn’t be the only leak in the system so it wouldn’t take long for the cost to quickly add up for several leaks of this size.

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.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

 

 

 

What Is A Btu?

A Btu, or British Thermal Unit, is a traditional unit of energy and is a measure of the heat content of fuels.

Originally, the Btu was the amount of energy needed to increase the temperature of 1 pound of liquid water by 1 degree Fahrenheit.  The term became common among engineers in the late 1800’s.

A single Btu is insignificant in terms of the amount of energy used by a single household or by an entire country. In 2013, the United States used about 98 quadrillion (written out, 1 quadrillion is a 1 followed by 15 zeros) Btu of energy.

One Btu is approximately equal to the energy released by burning a match.

Match

Interesting Energy Conversion Factors

Energy source Physical units and Btu (averages,¹ 2012)
Electricity 1 kilowatt hour = 3,412 Btu
Natural gas 1 cubic foot = 1,025 Btu
Motor gasoline (10% ethanol) 1 gallon = 120,524 Btu
Diesel fuel 1 gallon = 138,690 Btu
Heating oil 1 gallon = 138,690 Btu
Propane 1 gallon = 91,333 Btu
Wood 1 cord = 20,000,000 Btu (Estimated)

1Weighted averages across different contexts of each fuel such as imports, exports, production, and consumption. Source:  www.eia.gov/EnergyExplained by the U.S . Energy Information Administration

EXAIR manufactures the Cabinet Cooler System.  The Cabinet Cooler System is a low cost, reliable way to cool and purge electronic control panels.  They incorporate a vortex tube to produce cold air from compressed air – with no moving parts! EXAIR Cabinet Cooler Systems are available for NEMA 12, 4, and 4X type enclosures.  For the most efficient way to operate Cabinet cooler, a thermostat control system would be utilized. The standard thermostat control systems include an adjustable thermostat factory set at 95F.  Also, available is the ETC Electronic Temperature Control, providing precise control with easy adjustability and a digital readout.

Cabinet Cooler Family
EXAIR Cabinet Cooler Systems

In the United States, the power of HVAC (Heating Ventilating and Air Conditioning) systems is often expressed in BTU/hr.

The EXAIR Cabinet Cooler Systems are available with cooling capacities ranging from 275 to 5,600 Btu/hr.  To cool the down the equivalent of 98 quadrillion Btu’s of energy used by the US in 2013, it would take 17.5 trillion of our largest Cabinet Cooler Systems!

If you would like to find out how many Btu’s of cooling your electrical cabinet needs, please fill out and send in the Cabinet Cooler Sizing Guide and we can let you know.

Brian Bergmann
Application Engineer
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Match Photo courtesy of Samuel M. Livingston via Creative Commons License

Energy Rebates and EXAIR Products

In case it goes unnoticed, EXAIR focuses on engineered compressed air point of use products to ensure that our customers are utilizing their costly utility as efficiently as possible.  The main benefits to purchasing EXAIR products are the support you receive from us at EXAIR, the quality of the product, the savings in compressed air, and the increase in safety.  Another added benefit is a large number of utility companies are offering rebates on the purchase of engineered nozzles, just like the Super Air Nozzles that EXAIR offers.

Many energy providers offer these energy rebates for commercial or industrial users.  Here in the Cincinnati area, Duke Energy offers rebates on items such as lighting, air compressors, engineered air nozzles, heaters / dryers for extrusion machines, energy management systems, variable frequency drives, data center equipment, even food service equipment, custom incentives, and many other items.

Duke Energy Rebate
Example of our local energy rebate offering for Engineered Nozzles

For each engineered compressed air nozzle that is installed, in order to meet the rebate requirements they must flow less than or equal to given flow rates in SCFM at 80 psig inlet pressure. The pipe sizes, flow rates, and EXAIR equivalents are shown below.

EXAIR Engineered Air Nozzle Part Number EXAIR Flow Rate @ 80 psig
#1102/#1103 – 1/8 NPT 10 SCFM
#1100/#1101 – 1/4 NPT 14 SCFM
#1108SS-NPT/#1109SS-NPT/#1110SS-NPT
All are 1/8 NPT
2.5, 4.9, 8.3 SCFM
respectively
#1003 – 3/8 NPT 18 SCFM

By just replacing the nozzles the customer saved 2.7 SCFM per nozzle.If we take an example such as the EXAIR Case Study  shown below for 1/4″ copper tube that was being used as an open ended blow off.  The copper tubes were consuming 19.6 SCFM at 100 psig inlet pressure, there were 10 machines with one line per machine operating 40 hours, 52 weeks per year.   The customer retrofitted the open pipes with a model 1100 Super air nozzle and was able to reduce the air consumption by 2.7 SCFM per nozzle.  If they were to purchase these nozzles this year, current list price for a model 1100 Super Air Nozzle is $36.00 USD, then apply for the energy rebate offered by Duke Energy and receive $20.00 per nozzle replaced.  The total savings and return on investment is shown below.

Case Study 1561
EXAIR Model 1100 Super Air Nozzle Replaces Open Copper Pipe Blow Off

10 nozzles x 2.7 SCFM = 27 SCFM  x 60 minutes per hour x 8 hours per day x 5 days per week x 52 weeks per year = 3,369,600 SCF of compressed air saved per year.

3,369,600 / 1,000 SCF x $.25 = $842.40 USD savings in compressed air per year.

Cost Savings per week = $16.20 USD

Total purchase cost is  $36.00 x 10 nozzles = $360.00 USD

Energy Rebate = @20.00 per nozzle x 10 nozzles  = $200.00 USD in rebates.

$360.00 USD purchase price – $200.00 USD energy rebate = $160.00 USD final purchase cost.

Return on investment at a savings of  $16.20 USD per week is

$160.00 / $16.20 = Less than 10 weeks pay back!

By applying for the energy rebate this customer could reduce the ROI of this air savings project from just over 22 weeks (which is still very good) to less than 10 weeks.

If you would like to learn more about whether there are Industrial energy rebates available in your area, contact an Application Engineer and let us know where you are located and who your energy provider is.

We will help you determine the correct engineered solution to save your compressed air as well as help you to apply for eligible energy rebates in your area.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

 

Calculating Compressed Air Cost & Savings Made Easy

If you have ever looked through our catalog, website, blog, twitter feeds, or even our Facebook page, you will see that we can almost always put a dollar amount behind the amount of compressed air you saved by installing EXAIR’s Intelligent Compressed Air Products.   No matter which platform we use to deliver the message, we use the same value for the cost of compressed air which is $.25 per 1,000 Standard Cubic Feet of compressed air. This value is derived from average commercial and industrial energy costs nationwide, if you are on either coast this value may increase slightly. On the positive side, if your cost for compressed air is a bit more, installing an EXAIR product will increase your savings.

So where does this number come from?   I can tell you this much, we didn’t let the marketing department or anyone in Accounting make it up.   This is a number that the Engineering department has deemed feasible and is accurate.

To calculate the amount we first look to what the cost per kilowatt hour is you pay for energy.  Then we will need to know what the compressor shaft horsepower  of the compressor is, plus the run time percentage, the percentage at full-load, and the motor efficiency.

If you don’t have all of these values, no worries.   We can get fairly close by using the industry accepted standard mentioned above, or use some other general standards if all you know is the cost of your electricity.

The way to calculate the cost of compressed air is not an intense mathematical equation like you might think.  The best part is, you don’t even have to worry about doing any of the math shown below because you can contact us and we can work through it for you.

If you prefer to have us compare your current compressed air blow off or application method to one of our engineered products, we can do that AND provide you a report which includes side by side performance comparisons (volume of flow, noise, force) and dollar savings. This refers to our free Efficiency Lab service.

EXAIR's Efficiency Lab is a free service to all US customers.
EXAIR’s Efficiency Lab is a free service to all US customers.

If you already know how much air you are using, you can use the Air Savings Calculators (USD or Euro) within our website’s knowledge base. Just plug in the numbers (EXAIR product data is found on our website or just contact us) and receive air savings per minute, hour, day and year. We also present a simple ROI payback time in days.

Now, back to the math behind our calculation.
Cost ($) =
(bhp) x (0.746) x (#of operating hours) x ($/kWh) x (% time) x ( % full load bhp)
——————————————————————————————————————————
Motor Efficiency

Where:
bhp
— Compressor shaft horsepower (generally higher than motor nameplate Hp)
0.746 – conversion between hp and KW
Percent Time — percentage of time running at this operating level
Percent full-load bhp — bhp as percentage of full load bhp at this operating level
Motor Efficiency — motor efficiency at this operating level

For an average facility here in the Midwest $0.25/1,000 SCF of compressed air is accurate.   If you would like to attempt the calculation and or share with us your findings, please reach out to us.   If you need help, we are happy to assist.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

 

The Heat is On!

Well, it is here.  The middle of summer cannot be denied in Cincinnati this week.  We have had a high temperature of at least ninety degrees the last five days with near 100% humidity.  These are the days when you have to either work very earlier in the morning or very late at night to get any yard work done.  You’ll notice that the most of our blogs the last couple weeks have been about keeping things cool, like Cabinet Cooler systems, or High Temperature Cabinet Coolers.  I’m not one to buck a trend, so I’m going to talk about cooling as well, but I will talk about cooling a manufactured product.

A customer this week was designing a new plastic extrusion system and he needs to quickly cool four plastic extrusions strands from 400 degrees Fahrenheit to 120 degrees at a fairly high feed rate.  In the past the customer had used an immersion bath followed by a blow off station using EXAIR’s Air Knives, Air Wipes, or Super Air Nozzles depending on the plastic extrusions geometry.  The immersion bath would use the specific heat of the water to quickly take away the heat from the extruded plastic.  This process had worked well for him in the past, but the immersion bath was expensive to build and maintain.  For these reasons, he was looking for an alternative.

What is going to cool better than water?  The water in the immersion bath has a very high specific heat, which is what makes it such a good material for cooling large amounts of heat very quickly.  Specific heat is the amount of energy it takes to raise 1 pound of mass 1 degree Fahrenheit.  One British Thermal Unit (BTU) is the amount of energy it takes to heat or cool one pound of water one degree.  A BTU is 1,055 Joules, which is a very high specific heat compared most other common materials.  So we can’t change the immersion liquid, but could we come up with a better process?

Well of course we can.  We can use both the specific heat of water and the latent heat of water.  The latent heat is the amount of energy water takes to evaporate.  The latent heat of water is 970.4 BTU per pound.  If we can use both the specific heat of water and the latent heat of water, we can increase our cooling and not need a large, expensive immersion bath.  The customer came up with the idea of using Atomizing Spray Nozzles and a blow off station to get the same amount of cooling but without needing a water bath.  By spraying a fine mist of water onto the extrusions, we create almost the same amount of conduction with the water and the plastic.  The water takes out the energy of rising from room temperature to its boiling point, then takes out the energy of evaporating, and then the air dries the remaining water and takes away any more heat that may be remaining.

Dave Woerner
Application Engineer
davewoerner@exair.com
@EXAIR_DW

 

History of Compressed Air

The first use of compressed air did not come from compressors but the human lung. Healthy lungs can exert a pressure of .3 to 1.2 psi. Primitive people used the power of their lungs to propel darts from a blow gun. We use our lungs to blow off debris, stoke a fire, create sounds by voice and by musical instruments.

Around the third millennium B.C. , people began to melt metals such as gold, copper, tin and lead. Higher temperatures were needed requiring large volumes of air to stoke the furnaces: more than what the human lung could provide. Egyptian and Sumerian metallurgists used the wind directed through pipes for their work. Eventually tbellowhese were replaced by hand-operated bellows and then around 1500 B.C. the more efficient foot bellows came into use.

Bellows driven by foot or by water wheel proved a reliable compressor for more than 2,000 years. But as blast furnaces developed, so did the need for increased air compression. In 1762, John Smeaton built a water wheel-driven blowing cylinder that began to replace the bellows. Inventor John Wilkinson introduced an efficient blasting machine in England in 1776 and age of pneumatic energy became universally embraced.

Thus far, air compression was used mostly for the mining and the fabrication of metals. Blowing machines supplied a combustion blast to metallurgic furnaces and ventilation to underground mines. The idea of using compressed air to transmit energy became popular about 1800 when the newly invented pneumatic rock drill was used to connect Italy and France with an 8-mile rail tunnel under Mt. Cenis. This was a super feat for its time and garnered international interest spawning a flurry of inventions from air operated motors to clocks to beer dispensers.

Many engineers theorized compressed air as the energy distribution system of the future. However, electricity advocates held strong to their belief that pneumatic plants would eventually be trumped by electricity. Neither side was truly right and the debate still festers today. Much emphasis is being placed on energy conservation and the use of compressed air. The argument holds true today as it did back then, compressed air is a viable sources of transferring energy and will not go away. It’s prudent use of compressed air, as with any energy source, that is paramount.

Engine block blow off

The use of drilled or open pipe is energy wasteful. For 30 years EXAIR has been helping conserve compressed air with their engineered nozzles. These are designed to provide greater volumes of air than the volume of compressed air used which is a green alternative to drying, cooling, and blow off applications.

If you are interested in conserving your compressed air, one of our application engineers would be happy to assist you. Feel welcomed to give them a call at 1-800-903-9247 or click the chat icon in the upper left hand corner of this page.

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax (513) 671-3363
Web: http://www.exair.com
Twitter: http://www.twitter.com/exair_jp
Facebook: http://www.facebook.com/exair

EXAIR Receives the 2012 Environmental Protection Award

I know, I know, it’s not good to boast or brag.  I don’t write this blog to brag about how we maintain such a high service standard, product quality or 99.9% on time shipping record.  I write this to thank all of our customers who have voted for us and helped us to reach this point in our life as a company.   With the help of our customers we brought home another award.

2012EP_trophy330pxw

This is the 2012 Environmental Protection Award for New Products in the Energy category.  The EXAIR product that brought this home is our Data Logger for the Digital Flow Meter.

dfmpp_datalogger300x300

This product is not only able to help you monitor your compressed air use, but quantify and track it.  This is the perfect way to justify installing the Intelligent Compressed Air Product to your plant manager.

dataloggerPRce_559wide

It is one of thousands of products that EXAIR brings to you with the highest quality and customer service standards.  Thanks for all the support and we can’t wait to see what the future holds.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF