Industrial Utility Efficiency    

System Assessment

“Retro-Commissioning” (ReCX) of compressed air systems has become a trendy activity with many utility demand-side-management programs emerging in the last 5-10 years.  This is intended to be the process of “tuning up” a compressed air system, getting low cost savings from mostly adjustments and repairs.  The term was borrowed from the building/HVAC industry, where it means to get a system operating as it was originally “commissioned”. 

Compressor Controls

UniFirst is one of North America’s largest workwear and textile service companies. They outfit nearly two million workers in clean uniforms and protective clothing each workday. Founded in an eight-stall garage in 1936, the Company has grown to 240 customer servicing locations throughout the U.S. and Canada servicing 300,000 business customer locations. The subject of this article is an energy-saving Air Demand Analysis (ADA), conducted by Kaeser Compressors, at UniFirst’s centralized 320,000 square foot hub Distribution Center located in Owensboro, Kentucky.

Piping Storage

Technology is available which enables a compressed air flow meter to measure not only the magnitude of the flow, but also the direction. Why is this important? In this article we will describe two case studies where bi-directional compressed air flow measurement plays a key role to come to the right conclusions. In the first case study, we will describe an electronics manufacturing plant, which has a large interconnected ring network with two air compressor rooms located in different buildings. The two air compressor rooms are about five hundred feet apart. In the second case study, the effect of compressed air flow measurement upstream of a local receiver tank is described.

End Uses

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.

Pressure

A Canadian chemical plant installed a large heated blower-purge style compressed air dryer, years ago, to condition the instrument air system against freezing temperatures.  The dryer selected was oversized for the connected air compressors and had unused on-board energy savings features.  A compressed air assessment revealed the site air compressors and compressed air dryers were running inefficiently and causing in-plant pressure problems.  Repairs to a compressed air dryer and the replacement of aging air compressors and dryers has reduced compressed air energy costs by 31 percent.

Air Treatment/N2

A pharmaceutical product manufacturer spends an estimated $137,443 annually on electricity to operate the oil-free air compressors in its compressed air system. The compressed air system operates well and is providing the level of purification required.  Our team visited the plant and identified a group of projects which could reduce compressed air demand and reduce energy costs by $42,248 – or 31% of current use.

Leaks

Compressed air optimization measures adopted by PTMSB have reduced the consumption of compressed air by 31 percent resulting in savings of about 3,761,000 kWh per year in energy consumption. The monetary savings are MYR 1,090,627 per year ($255,000 USD). The CO2 reduction is estimated at 2,735 ton per year.

Pneumatics

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.

Vacuum Blowers

Every municipality and utility is facing the reality of rising energy costs. In 2010, the Town of Billerica, MA, which is located 22 miles northwest of Boston with a population of just under 40,000 residents, engaged Process Energy Services and Woodard & Curran to conduct an energy evaluation of the Town’s Wastewater Treatment Facility (WWTF) and pump station systems sponsored by National Grid. The objective of the evaluation was to provide an overview of each facility system to determine how electrical energy and natural gas were being used at the facility and to identify and develop potential costsaving projects.
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.
Figuring out the energy savings for the switch from pneumatic to electric tools requires an estimate of energy use for each case. The effect of replacing a few tools in a large compressed air system may be too small to detect using power monitoring on the air compressors. However, it is still a good practice, and when part of a larger program to reduce air consumption, the combined efforts will amount to something measureable. Another positive aspect may be that reduced compressed air use frees up needed air compressor capacity.
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.
A Canadian chemical plant installed a large heated blower-purge style compressed air dryer, years ago, to condition the instrument air system against freezing temperatures.  The dryer selected was oversized for the connected air compressors and had unused on-board energy savings features.  A compressed air assessment revealed the site air compressors and compressed air dryers were running inefficiently and causing in-plant pressure problems.  Repairs to a compressed air dryer and the replacement of aging air compressors and dryers has reduced compressed air energy costs by 31 percent.
Insufficient focus at the design phase will kill a project. In one aerospace project, insufficient detail was paid to the physical size of the air compressor. The compressor didn’t fit in the allocated space—requiring the extension of the building, and costing tens of thousands of unbudgeted dollars. That had a significant, negative impact on the project return. 
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.
To produce healthy, high-quality cooking oil, this food processing company crushes and processes oil seeds shipped in from local farms. The oil produced is thought to be the healthiest cooking oil available, because it is low in saturated fat, high in monounsaturated fatty acid (MUFA), and polyunsaturated fat (PUFA), like omega-3 fatty acids. To increase the energy efficiency of its oil seed crushing and processing facility, the company optimized its compressed air system by combining three separate systems into one. Some end-use optimization was done to correct low pressure, particularly caused by some critical high-flow, short-duration events.
Technological trends in plastics manufacturing are driving the costs of production down. In industrial PET blow molding specifically, two innovative techniques have had major impacts over the last 15 years: “light weighting” the plastic bottles, and recirculating high-pressure compressed air. Both have helped to improve the energy efficiency of PET blow molding by reducing compressed air requirements dramatically.
PET Power Containers, a Canadian manufacturer of PET plastic containers, had plans for expanding its operations with the addition of more blow-molding equipment. Before the expansion could happen, however, the company needed to assess its compressed air system. Based in Vaughan, Ontario, PET Power provides a dizzying array of differently shaped and sized plastic bottles. Their operations run 24/7, and compressed air plays a key role in their primary manufacturing applications, including PET blow molding, PET preforming, and labeling bottles.
A Canadian fiberglass plant has completed a lengthy compressed air improvement journey and achieved significant efficiency gains by applying “the systems approach.” Along the way, the company ran across many frustrating problems, the solutions to which were only determined after the entire system was monitored holistically using data loggers. The overall compressed air audit led to a reduction in energy usage of 48 percent, yielding savings worth $17,500 per year. The project also qualified for a large utility incentive of $32,000 with a calculated payback of 4.4 years.