System Assessments

Compressed air users looking for energy reduction often identify their air compressors as a prime area for savings potential. But …what about end uses? There are a large number of obvious measures that can be implemented, such as leakage reduction, reducing open blowing and eliminating inappropriate uses..however, there are other more technical opportunities available that involve properly specifying or redesigning existing pneumatic circuitry in compressed air operated machines and processes.

This Midwestern prepared food company now spends \$269,463 annually on energy to operate their compressed air system. This figure will increase as electric rates are raised from their current average of 6.2 cents per kWh. The set of projects recommended below will reduce these energy costs by \$112,902 or 41%. In addition, these projects will enhance productivity and quality and reduce equipment maintenance costs. Estimated costs for completing the projects total \$146,102, which represents a simple payback of 15.6 months.

Recently, The Kroger Company’s Indianapolis bakery identified the use of compressed air in a blow-off and conveyor gap transfer as a major source of energy loss and cost waste. According to the U.S. Department of Energy, “inappropriate use” of compressed air like blow-off produces high pressure atmosphere bleed leading to significant energy loss and unnecessary operational costs. Carrying a 10-15% efficiency return (according to the Department of Energy), compressed air applications can often be achieved more effectively, efficiently and less expensively with alternative solutions using a high flow rate and moderate pressure.

One major problem that causes severe damage or system failure for any water treatment station is water hammer shock waves. “Water Hammer” or “Hydraulic Shock” is a pressure surge or shockwave resulting when a fluid (usually a liquid but sometimes also a gas) in motion is forced to stop or change direction suddenly (momentum change). The reversed momentum then continues to multiply the further it travels before being stopped.

"The Numbers Don’t Lie". It’s a popular saying everyone has heard before, applied to a variety of situations – political statistics, figures backing up an athlete’s performance and budget data.

Thirty percent is a big number. Applied to the above scenarios, it could entail a landslide victory or a hitter gaining entry into the Baseball Hall of Fame. But just imagine, if the manager of a wastewater treatment facility were to trim 30 percent from their operating costs, he or she might also consider that a landslide victory of their own.

Since the cost of energy has dramatically increased during the past few years, it seems that energy audit companies have opened shop on more city street corners than coffee shops in Seattle. 

In addition to the mass numbers and abundant varieties of these energy savings promoters, there have been an equal number of energy audit articles written for the engineering magazines.

A comprehensive compressed air system analysis should include an examination of both air supply and usage and the interaction between the supply and demand. Auditors typically measure the output cfm of a compressed air system and the input kW, calculate energy consumption in kilowatt-hours, and determine the annual cost of operating the system. The auditor may also measure total air losses caused by leaks and locate those that are significant.

When it comes to conserving energy in compressed air nothing is sexier than a big, old, oil-free 300 horsepower variable speed drive air compressor coupled with a heat of compression dryer tied to an energy management system with all the trimmings. If you’re like me, it’s hard not to let out a manly grunt after reading that sentence.

A leading soft drink bottling manufacturer’s compressed air needs were threatening to exceed its Michigan plant’s compressed air capacity. Faced with the cost of buying a new compressor, the soft drink bottling manufacturer re-assessed their compressed air use to identify compressor and energy savings opportunities. In the audit, the soft drink bottling manufacturer identified the use of compressed air in a gap transfer as a source of compressed air and energy inefficiency.

With energy cost increasing at 7.5% per annum for the past few years, most facilities managers and maintenance professionals are looking for the best opportunities for excellent return on investment projects, which can drive their operating costs in the opposite direction. Compressed air is an area where significant improvements are readily available.