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.
Compressed air is often overlooked in energy studies. For those willing to look, however, it is a land of opportunity. Since it takes about 8 hp of electrical energy to produce 1 hp worth of work with compressed air, it is also particularly rewarding to evaluate and optimize the compressed air system in your facility. In this article, we evaluate four specific areas of a compressed air system that can provide significant energy savings.
In this article, we review the operating principles of both basic types of pulse-jet dust collectors — bag (sock), and reverse flow filter. We then examine the effects of various installation and accessory selection issues through several case studies, providing examples of how to fix the issues and optimize the system’s compressed air use.
Vale in Thompson, Manitoba, Canada has reconfigured a system of large turbo compressors in their mining, milling, smelting and refining operation and gained very large energy savings through a series of improvement projects. In addition, these projects qualified for some significant financial incentives from their local power utility.  Vale is a large multinational mining company with headquarters in Brazil.  Vale operations focus on the production of iron ore, coal, fertilizers, copper and nickel.  The Thompson Manitoba operations consist of mining, smelting, milling, and refining of Nickel in the 250 acre complex that employs 1,500 people.
Compressed air audits for chemical and petrochemical plants have many characteristics in common with audits in other industries, but there are some differences in the way these businesses run that impact the goals of the typical audit and how that audit is conducted. In chemical and petrochemical facilities, the reason for auditing the demand side is different than that of other industries. Additionally, there are frequently applications with opportunities for improvement that are not always seen in other industries.  
A factory expanded their production facilities in response to a new product line being introduced in their plant. The plant was to run as a separate entity with its own utility services. Because this company is very conscientious about their energy consumption, they specified top-of-the-line compressed air production equipment to keep their costs low while maintaining the very clean air quality required by their product. This equipment should have worked wonderfully. Unfortunately, events transpired, and poor decisions were made that pushed their system out of control, resulting in unexpected inefficient compressor operation and higher-than-desired energy consumption.
This article introduces a new and useful compressed air system parameter called the “Compressor System Factor,” or CSF. The CSF of a given system defines the relationship between an air compressor, its system, and how the compressor is being operated. Knowing the CSF of a system allows comparisons to be made between existing operating characteristics and the characteristics of a proposed system. Changing a system by applying energy efficiency measures like adding storage receiver capacity, changing pressure bandwidth, or switching to different compressor control modes also changes the CSF. The results of the change can be easily predicted using the CSF number.
Corporate announces it is participating in the ISO 50001 Energy Management certification program and issues the edict to all itsmanufacturingfacilitiesto come up with plan to reduce energy consumption by 25%. Plant management calls a meeting to discuss how this ambitious goal can be met. Since energy is one of the largest controllable components in a compressed air system, the group decides to start there. Arecentsupply side assessment conducted in conjunction with a compressed air specialist confirmed the compressors are energy hogs. Based upon the analytical simulation run by the specialist, a recommendation was made to upgrade the compressor network with a System Master Control. The project is moving forward making it good starting point in the overall energy reduction plan. What next?
Acrylon Plastics located in Winkler, Manitoba, Canada manufactures an extensive variety of custom plastic parts for a wide range of end use applications. Years ago changes to their production volumes increased the compressed air flows to above what their compressed air system could deliver. As a result the plant pressure would fall to low levels during production peak demands, which negatively affected sensitive compressed air powered machines. In addition to this during light plant loading conditions the air compressors would run inefficiently. Plant personnel tried a variety of strategies to deal with the plant peaks, with the most efficient solution coming as a result of installing VSD style compressors and pressure/flow control.
As readers of this publication know, there are many ways to save energy in industrial compressed air systems. One common supply side technology is the variable frequency drive (VFD) of the compressor. It is well-documented that positive-displacement compressors with VFDs provide cost-effective savings in comparison to inlet modulating, load-unload, and variable displacement control.
Quite a number of worst-case compressed air scenarios have been encountered over the years but none may compare to the conditions that existed in a metal foundry somewhere in North America. For reasons you are about to discover, we will not reveal the name of this factory or its location, in order to protect the innocent from embarrassment.