Compressed air is used throughout the manufacturing industry in a multitude of applications. When compressed air systems aren’t operating at peak efficiency, they become a huge drain on the bottom line. Air systems are vulnerable to energy waste, leaks, contaminants, pressure variability and artificial demand. Problems might be attributable to incorrect piping, high operating temperature, poor condensate control or other detrimental conditions.
Installation and maintenance performed in accordance with the manufacturer’s specifications should alleviate many of these issues. When problems occur, seemingly minor adjustments often can save a plant thousands of dollars.
Optimizing compressed air systems can be approached both tactically and strategically. Energy-saving devices, audits, and monitoring tools and techniques are designed to reduce the costs of operation and maintenance, increase availability and reliability, and prolong equipment life. Performance improvements also stimulate productivity increases, reduce unscheduled downtime, increase production and provide a safer work environment.
VFD retrofits: When a compressor operates at full load regardless of demand, it wastes significant amounts of energy and generates excessive noise. Outfitting the compressor with a variable-frequency drive (VFD) often can produce significant electric energy savings. VFDs enable part load control by modulating the drive speed to match compressor output to demand while maintaining system pressure.
Several factors determine whether a compressor can or should be converted to variable speed operation. Upfront costs are less of a concern as the price of VFD technology continues to fall. Energy savings, air system productivity, and operating equipment performance should weigh more prominently in the decision. Independent consultants like Scales Air Compressor and Air Power USA help plant professionals assess the load profile, determine where greater efficiencies are possible, and apply VFDs where suitable.
Compressed air audits: Compressed air system audits assess efficiency and costs and pinpoint opportunities for improvement. These examinations compare current compressed air supply to demand, and evaluate variables such as flow rate, power consumption, pressure, leaks, temperature, moisture content, air quality, capacity and inappropriate usage. The audit program starts with the baseline measurements and calculates energy use and costs. This leads to strategies that reduce energy costs, improve air quality and optimize performance.
Although several engineering and technology firms offer compressed air audit services, those who prefer a do-it-yourself approach might consider the D-I-Y Efficiency Quotient air auditing process from Quincy Compressor. Start the process by assigning values to variables in a worksheet. This assesses your compressed air system efficiency. Next, verify the findings with a data logger and the help of an authorized Quincy Compressor distributor. Finally, upload the logged data to the Efficiency Quotient Web site, which models multiple solutions and generates an audit report and financial summary.
Machine health monitoring: Historically, monitoring compressed air systems to ensure they operate within acceptable limits is an assignment that has been encumbered by cost and time constraints. Now, emerging sensor technologies are facilitating the concept of machine health monitoring.
Sensors measure specific operating variables and can feed data to control systems continuously, on demand, or at predetermined intervals. Given this input, predictive maintenance is better able to prevent machine failures, and corrective maintenance can eliminate identified leaks or other inefficiencies.
According to Rob Conant, Dust Networks’ vice president of marketing and business development, “When monitoring is constrained by hard-wired control systems, it’s difficult, expensive and sometimes impractical to add sensor points. We decided to bring down the cost of getting information by developing battery-operated, wireless sensor networks with nodes that can be affixed to virtually any control point –- quickly and easily.” He adds, “Open wireless standards allow this data to be shared with control and asset management systems that can turn the data into actionable information.”
Outsourced monitoring: If you don’t have the resources to monitor compressed air performance continually in-house, companies like Atlas Copco and Ingersoll-Rand can link your systems to an online monitoring system and manage the task for you. These monitoring systems provide technicians with around-the-clock access to your systems’ performance variables. Automatic, electronic notifications promptly warn of problems, and diagnostics are handled remotely to help avoid unnecessary service calls. When service is required, the right skills and parts can be factored into the planning process so that downtime is minimized.
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at Sheila@addcomm.com.