Control Your Compressed Air

March 22, 2016Ken Bean

Compressed Air Controls

Improving and maintaining compressed air system performance requires not only addressing individual components, but also analyzing both the supply and demand sides of the system and how they interact, especially during periods of peak demand. This practice is often referred to as taking a systems approach because the focus is shifted away from components to total system performance.

Latest edition controllers from both the OEM and aftermarket suppliers offer the most sophisticated algorithms for unit control and incorporate sensitive digital sensing devices which all combine to give you the most efficient and reliable control. The better control you have of your compressor allows operators to select the lowest possible operating pressure allowing the plant to save significant money on operations and maintenance costs. Almost all of these controllers offer remote monitoring and remote control where operators are not required to be standing by in the compressor area to monitor data points or select update operating methods.

Controls from IZ Systems offer a complete compressor control automation package capable of handling any type of compressor, dryer, cooling tower or chiller system. Thus allowing integrated control of the entire system which further reduces the operations cost and further improves reliability.

Should I Use Compressed Air?

March 15, 2016March 15, 2016Ken Bean

Decisions, Decisions!

Last month I posted an article discussing the options of using compressed air vs. electric. There were several questions regarding cost calculations.

As a follow up, Todays post will discuss compressed air cost calculations to determine if compressed air should be used for specific applications.

This allows you to determine if compressed air should be used in specific applications (ie. as fans or blowers), or if other electric-motor operated equipment would be more efficient.

First calculate the volume of air produced annually for a specific operation by multiplying:

horsepower (hp)

cubic feet per minute per horsepower (cfm/hp)

total operating hours per year (hr/yr)

60 minutes per hour (60 min/hr)

% time fully loaded

% full-load horsepower

Volume of air produced annually

Then calculate the cost per 1,000 cubic feet (cf) by dividing the total energy cost to operate the air compressor by the volume of air produced annually, then multiply by 1,000. Cost per year / Volume of air products * 1000 cf

Example Calculations

The following example represents a typical small job-shop manufacturer.

A facility operates a 100 hp air compressor 4,160 hours annually. It runs fully loaded, at 94.5 percent efficiency, 85 percent of the time. It runs unloaded at 25 percent of full load at 90 percent efficiency, 15 percent of the time. The electric rate is $0.06 per kWh, including energy and demand costs. The cost per year to power the air compressor will be as follows.

Fully Loaded

Unloaded

The total annual energy cost to operate the air compressor is $17,524. The following calculation shows how much it will cost to use compressed air to operate a specific end use. Assume 3.6 cfm per horsepower and that this rate applies when the compressor is fully loaded.

Volume of air produced annually Cost per 1,000cf ($17,524 / 76,377,600) * 1000 = $0.23

Over the life of a compressor, energy costs will be five to 10 times the compressor’s purchase cost. Energy savings can rapidly recover the extra capital required to purchase an energy-efficient air compressor .

A 1.17 rated horsepower air operated mixer uses 45 cfm at 80 pounds-per-square-inch (psi) and operates 40 hours per week. The cost of the compressed air to operate this motor over a year is $1,292. A comparably sized electric motor of Energy Policy Act (EPACT) efficiency, rated for hazardous locations, is around $350. The cost to operate the EPACT motor under the same conditions is less than $100 per year. Including installation, payback is under one year.

Utilizing Compressed Air Storage

December 15, 2015December 21, 2015Ken Bean

If you look at most any industrial compressed air system you will find a receiver located somewhere in the layout. However, just having a receiver does not mean the system is fully utilizing the capability of the storage.

Properly utilized compressed air storage should allow a compressed air system to meet its peak demand needs and help control system pressure without starting additional compressors. The correct type and quantity of air storage depends on air demand patterns, air quantity and quality required, and the compressor and type of controls being used. An optimal air storage strategy will enable a compressed air system to provide enough air to satisfy temporary air demand events while minimizing compressor use and pressure.

To properly utilize the stored compressed air the pressure in the receiver needs to be stored at a higher pressure than the system pressure. The strategy is to allow the differential between these 2 pressures to be sustained by incorporating a pressure flow controller (PFC) and/or metering valves.

This allows the pressure in the demand side to be reduced to a stable level that minimizes actual compressed air consumption. PFCs are added after the primary receiver to maintain a reduced and relatively constant system pressure at points of use, while allowing the compressor controls to function in the most efficient control mode and discharge pressure range. Properly applied, a PFC can yield significant energy savings in a system with a variable demand load.

A professional air audit can determine the proper storage size requirements.

Turn It Off

December 8, 2015December 8, 2015Ken Bean

Those big air compressors in the back that nobody wants to look at consume a huge amount of energy. A 100 horsepower compressor can cost $75,000 per year in energy costs (based on 8,760 hours at $0.10 per kilowatt hour). Utilizing automation, storage and flow control, system balancing and best use practices along with other details, can allow you to turn some compressors off. Just running the above mentioned 100 HP compressor during lunch each day can cost up to $3,000.00 annually.

An Air Audit today could save thousands next year!

Saving Energy On Compressed Air Does More Than Save Money

December 1, 2015August 3, 2016Ken Bean

Approximately 70% of all manufacturers have a compressed air system. These systems power a variety of equipment, including machine tools, material handling and separation equipment, and spray painting equipment. Energy audits conducted by the U.S. Department of Energy (DOE) suggest that over 50% of compressed air systems at small to medium sized industrial facilities have low-cost energy conservation opportunities.

Significant air emissions are released when electricity is produced. A recent study for the state of Minnesota, indicated that one-fourth of the energy-related emissions of carbon dioxide, sulfur dioxide, lead and mercury are from generating electric power. Industry uses over 34% of this electricity. Reducing electricity used by compressed air systems will help improve everyone’s air quality.

A team of qualified auditing engineers is the correct way to evaluate your system.

Contact me today to schedule a consultation.

Compressed Air Alternatives

November 24, 2015November 24, 2015Ken Bean

Although compressed air is readily available and convenient to use in most plants, it is often more cost-effective to find an alternate solution to some problems. Some studies have shown that the overall efficiency of a typical compressed air system can be as low as 10% to 15%. With that in mind, using a fan or even modifying an air conditioning system to cool a component is likely to be less expensive in the long run than installing a compressed air vortex cooler.

Vacuum systems are more efficient and safer for cleaning than compressed air. Electric tools are less expensive to operate than their pneumatic counterparts, although torque and industrial durability need to be considered when selecting the right tool for the job. Ultimately, a person needs to consider all options and use compressed air only when it truly makes sense.

“The above statements are taken from the DOE Compressed Air Challenge website”

If you answer “yes” to any of the following, your use of compressed air can likely be reduced! We offer Free on site consultation to evaluate your compressed air needs.

Can this application use compressed air at a lower pressure?
Is the pressure required for this application in the range of a blower rather than a compressor?
Does the application use large volumes of air for short burst of time? ie. Chip blowing or bag house filter blow off
Is this application using compressed air for parts cooling or drying?