Industrial Utility Efficiency    

End Uses

A chemical plant spends an estimated $587,000 annually on electrical energy to operate their compressed air system. In addition, the plant has an expenditure on rental air compressors of equal or greater size - but this will not be covered in this article. The plant was built in the 1940s and modernized in the 1970s. The plant generates its own power and serves many processes. The average cost per kWh is $0.0359.
An electronics manufacturer with a very large compressed air system recently had a compressed air audit done in their plant to assess system efficiency. The audit discovered the system had been designed to be extremely efficient, yet some previously undetected problems were causing less than optimal operation. Despite being located in a tropical environment, this plant utilizes heat recovery to help reduce the overall energy consumption.
Parrheim Foods, a division of Parrish and Heimbecker, is an innovative starch, protein and fiber mill situated in Saskatoon, Saskatchewan, Canada.  The plant has improved system efficiency and reduced production problems by addressing some problems with the consumption of compressed air by their reverse pulse baghouse cleaning operations.  This effort has allowed them to turn off one of their 100 hp air compressors, saving significant electricity costs.
Compressed air is used as a convenient and often necessary source of air flow to perform blow-offs, cooling, or drying.  And since compressed air is a costly utility, a frequent recommendation in this magazine and audits is to reduce the compressed air use by using high efficiency engineered nozzles.  Using these nozzles is a good practice as they are designed in a way that uses the compressed air to accelerate the surrounding air to deliver the same mass transfer effect as a standard nozzle (or tube) with a much larger orifice.
At a Midwest window manufacturing plant, the cooling process for the plastic frame pieces, after leaving the extruder, was critical to process productivity and quality. Too much cooling air (or not enough cooling air) would generate scrap and rejected product. The plants’ 17 extruders and 55 separate blow-offs in these lines had similar cooling stations at the cooling boxes. They consisted of about three hoses at each exit frame angled down to the extruded piece moving past it. The compressed air flow was controlled by a manual control valve set by an operator. The operator used his experience to control the flow delivered and thereby control the product quality.
A major poultry processor and packager spends an estimated $96,374 annually on energy to operate the compressed air system at its plant located in a southern U.S. state.  The current average electric rate, at this plant, is 8 cents per kWh.
The intent of this article is to provide readers with simple examples of calculations one can perform to evaluate two sample energy efficiency projects for compressed air systems; pressure sensing vortex vacuum generators and outside air intake (for air compressors).
As a result of compressed air awareness training and a focus on energy management, two facilities in different parts of the world have reduced their compressed air demand substantially by removing vortex style cabinet coolers from some of their electrical panels and reworking the cooling systems.  These facilities were previously unaware of the high cost of compressed air and how much could be saved if other methods of cooling were used. This article describes some of their efforts in demand reduction.
Energy, in all forms, has always been a key Lantech focus. It was, in fact, a key element of the core packaging problem the company’s founders set out to address. They saw an opportunity to capitalize on an inexpensive and under-used resource – stretch film – to displace a high materials cost and energy intensive way of unitizing pallet loads of products – shrink bagging.
A large fabric mill has implemented an energy management system based on the ISO 50001 standard to track their compressed air system efficiency.  As a result of information gained from this system, and measures learned in some recent compressed air training, the company has reduced their compressed air system costs while at the same time achieving increased fabric production output. The savings were gained by not only optimizing the supply side of the system, but by also addressing the end uses.
In many parts of the country—and especially the Pacific Northwest—interest has surged in completing energy-saving compressed air system upgrades. The financial assistance from incentive programs, combined with the falling costs of efficiency-increasing technology, has made these projects very attractive to all those involved. The benefits for society, power companies and customers are immense.