## Opportunities to Save On Compressed Air

To start, what is an air compressor and why does it cost so much in electricity?  There are two types of air compressors, positive displacement and dynamic.  The core components for these air compressors is an electric motor that spins a shaft.  Like with many mechanical devices, there are different efficiencies.  Typically, an air compressor can put out anywhere from 3 SCFM per horsepower to 5 SCFM per horsepower.  (EXAIR settles on 4 SCFM/hp as an average for cost calculations.)  Equation 1 shows you how to calculate the cost to run your air compressor.

Equation 1:

Cost = hp * 0.746 * hours * rate / (motor efficiency)

where:

Cost – US\$

hp – horsepower of motor

0.746 – conversion KW/hp

hours – running time

rate – cost for electricity, US\$/KWh

motor efficiency – average for an electric motor is 95%.

As an example, a manufacturing plant operates a 100 HP air compressor in their facility.  The cycle time for the air compressor is roughly 60%.  To calculate the hours of running time per year, I used 250 days/year at 16 hours/day.  So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year.  The electrical rate for this facility is \$0.08/KWh. With these factors, the annual cost to run the air compressor can be calculated by Equation 1:

Cost = 100hp * 0.746 KW/hp * 2,400hr * \$0.08/KWh / 0.95 = \$15,077 per year in just electrical costs.

There are two major things that will rob compressed air from your system and cost you much money.  The first is leaks in the distribution system, and the second is inefficient blow-off devices.   To address leaks, EXAIR offers an Ultrasonic Leak Detector.  The Ultrasonic Leak Detector can find hidden leaks to fix. That quiet little hissing sound from the pipe lines is costing your company.

A University did a study to find the percentage of air leaks in a typical manufacturing plant.  For a poorly maintained system, they found on average that 30% of the compressor capacity is lost through air leaks.  Majority of companies do not have a leak preventative program; so, majority of the companies fall under the “poorly maintained system”.  To put a dollar value on it, a leak that you cannot physically hear can cost you as much as \$130/year.  That is just for one inaudible leak in hundreds of feet of compressed air lines.  Or if we take the University study, the manufacturing plant above is wasting \$15,077 * 30% = \$4,523 per year.

The other area to check is air consumption.  A simple place to check is your blow-off stations.  Here we can decide how wasteful they can be.  With values of 4 SCFM/hp and an electrical rate of \$0.08/KWh (refence figures above), the cost to make compressed air is \$0.25 per 1000 ft3 of air.

One of the worst culprits for inefficient air usage is open pipe blow-offs.  This would also include cheap air guns, drilled holes in pipes, and tubes.  These devices are very inefficient for compressed air usage and can cost you a lot of money.  As a comparison, a 1/8” NPT pipe versus an EXAIR Mini Super Air Nozzle.  (Reference below).  As you can see, by just adding the EXAIR nozzle to the end of one pipe, the company was able to save \$1,872 per year.  That is some real savings.

By following the Six Steps to optimize your compressed air system, you can cut your energy consumption, improve pneumatic efficiencies, and save yourself money.  With the added information above, you can focus on the big contributors of waste.  If you would like to find more opportunities to save compressed air, you can contact an Application Engineer at EXAIR.  We will be happy to help.

John Ball
Application Engineer
Email: johnball@exair.com

## Increasing Efficiency With EXAIR Super Air Nozzles

Earlier this morning I received a phone call from a gentleman in search of a more efficient compressed air solution.  The application was to remove thermoformed plastics from a mold immediately after the mold separates.  In the current state, the application is consuming ~40% of the available compressed air in the facility through the use of (9) ¼” open pipes, consuming a confirmed 288 SCFM at 60 PSIG.  Due to the use of an open pipe, this customer was facing a safety and noise concern through the existing solution.

After discussing the application need and the desire to reduce compressed air use, reduce noise, and add safety, we found a suitable solution in the 1101 Super Air NozzleInstalling (9) of these EXAIR nozzles will reduce the compressed air consumption by over 65%!!!  Calculations for this savings are below.

Existing compressed air consumption:  288 SCFM @ 60 PSIG

Compressed air consumption of model 1101 @ 60 PSIG:  11 SCFM

Total compressed air consumption of  (9) 1101 nozzles:

Air savings:

This is the percentage of air which the new EXAIR solution will consume.  To put it another way, for every 100 SCFM the current solution consumes, the EXAIR solution will only require 34.38 SCFM. Installing these EXAIR nozzles will result in lower operational cost, lower noise levels, and increased safety for this customer – all while maintaining or improving the performance of the blow off solution in this application.

EXAIR Application Engineers are well versed in maximizing efficiency of compressed air systems and blow off needs.  If you have an application with a similar need, contact an EXAIR Application Engineer.  We’ll be happy to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE