Compressed air: Find the leaks, lower the pressure, and measure the results
The “better practice” would measure compressor power before and after reducing pressure so the reward can be more accurately quantified before impacting a variable that influences operations. Compressor load conditions relative to time would be required to estimate savings.
For centrifugal compressors, engineering data corrected to site conditions and ambient temperatures is essential to estimate any potential savings. Depending on ambient conditions and internal components used in a given compressor, reducing pressure may have no impact on power.
Reducing system pressure can also impact compressed air demand. A common misconception estimates potential savings as a function of peak demand and system pressure. The actual influence on demand is a function of the change in pressure at the point where the gas is expanded. A better estimate will require detailed monitoring and analysis of a given system across all load conditions. Although energy savings can be realized easily by simply reducing compressor and system pressure settings, it is typically executed as an event. Sustaining results can be challenging.
For any production issue associated with compressed air, pressure is the most frequently assumed problem. Most facilities will prioritize measured production results over assumed compressor energy savings. As a result, restoring pressure settings to previous or higher settings is the typical response.
Measure the results
The “best practice” for compressed air systems requires a transition from executing random immeasurable events to a formal program with performance metrics and a team of individuals accountable for delivering monthly performance goals. When compressed air system performance goals are owned at the appropriate level within an organization, any negative variance is corrected. By focusing on delivering and sustaining reported results, compressed air system efficiency would be practiced regularly. With the appropriate level of visibility and accountability, an increase in leaks would be quantifiable, resulting in specific expectations with measurable results executed as a maintenance practice, not an isolated task.
Mark Krisa is director of Ingersoll Rand’s Global Service Solutions.