“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”.
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.
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.
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 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.
This northeastern U.S. automotive manufacturing facility spends $269,046 annually on energy to operate their compressed air system. This figure will increase as electric rates are raised from their current average of .019 cents per kWh. The set of projects, in this system assessment, reduce these energy costs by $110,166 or forty percent. Reliability of compressed air quality, however, is the main concern in this plant and the primary focus of this system assessment.
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.
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.
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.
EnergAir’s unrivalled expertise in compressed air management is helping to save in excess of $50,000 per year at Whirlpool Corporation’s Ottawa, Ohio production facility. Whirlpool is the largest global manufacturer of home appliances and employs almost 70,000 people in more than 60 production and technology centres around the world. The Whirlpool plant in Ottawa manufactures a market-leading range of trash compactors, chest freezers, upright freezers and refrigerators.
Boeing Canada Winnipeg (BCW) has been recognized with the best improvement project of 2013 within the Boeing enterprise worldwide. A cross-functional project team including BCW staff, Manitoba Hydro technical support, and design engineers from Alliance Engineering Services, Inc. used innovative high-pressure storage to reduce the required size of their air compressors and save substantial utility energy and demand charges.
Most of us understand each individual has a unique DNA combination. Compressed air is very similar, each compressed air system should be uniquely designed so the system performs in harmony. Properly managing the compressed air system requires an investigative audit to understand the nuances of the system and identify the most effective solution(s) for efficiency. Not investigating the system, before selecting improvements, would be like consenting to surgery without having an exam. Yet, this frequently occurs in businesses operating compressed air systems.
This is a food processing plant where processes and standards are controlled by FDA to AIB standards. Annual plant electric costs for compressed air production, as operating today, are $116,765 per year. If the electric costs of $3,323 associated with operating ancillary equipment such as dryers are included, the total electric costs for operating the air system are $120,088 per year. These estimates are based upon a blended electric rate of $0.085/kWh.
As you walk past the “sandblasting cabinet” back in the corner of the plant running alone and without the need for monitoring, does the thought of operational costs enter your mind? When it does, are you happy knowing the cabinet is automatic and does not need a full-time operator? Then, did you say to yourself, I wonder how much that abrasive media costs? How long does it last? Is this a more cost competitive alternative? Is there something that might last longer?
Compressed air reliability has been the obsession of both factory personnel and service providers for a number of years now. Constant availability of high quality air can be absolutely critical to maintaining efficient plant production. Most modern factories operate reliable compressed air systems – and more recently have also begun to focus on the efficiency of those systems. The objective of this article is to use a few real-life case studies of already reliable compressed air installations to illustrate the potentially huge economic benefits of also improving system efficiency.
Over many years of reviewing industrial compressed air production machinery, of many types and styles, there is one common thread or complaint; “push-to-connect pneumatic tubing connections/fittings are a continual source of compressed air leaks and production interruptions.” Probably seventy-five to eighty percent of push-to-connect type tubing fittings use flexible tubing selected for lower material cost and assembly rather than an alternate appropriate hard metallic tubing.
Chemical plants, due to their size and complexity, pose many challenges to the efficient and reliable operation of a compressed air system. There are so many places for hidden opportunities to be found in these large industrial complexes. We are normally dealing with several large centrifugal and rotary screw air compressors scattered across the complex. We encounter sites with well over thirty (30) desiccant air dryers of different types. Compressed air leaks can be found almost at will across the vast lengths of compressed air piping. Add to this the fact they are outdoor installations exposing all compressed air system components to the extremes of summer and winter. As you can imagine, it is a big task to simply understand the system.
This paper mill currently spends $1,747,000 annually on energy to operate the compressed air system at their plant located in the southwestern region of the U.S. The set of projects recommended, in this system assessment, could reduce these energy costs by $369,000 or twenty-one percent (21%). Estimated costs for completing the projects total $767,900, representing a simple payback of 25 months. More importantly, these projects will improve productivity, quality and maintenance costs - many associated with poor compressed air quality.
Based on the air system operating 8,760 hours per year, the group of projects recommended below could reduce these energy costs by an estimated $170,718 or 56% of current use. In addition, these projects will allow the plant to have a back-up compressor and help eliminate the rental expenditure for compressor maintenance or downtime.