How to maximize the efficiency of your compressed air system
Compressed air is a convenient, but expensive resource
Eliminating inefficient uses of compressed air is one of the most significant ways to save on your utility bill. Remedying air leaks and switching off compressors are two common tactics for boosting your bottom line. Using the right size of air compressor for your production needs is equally important.
Helping businesses discover no and low-cost ways to save power is an important part of our operational energy analytics program, and optimizing air compressor applications is one of the program's priorities. We asked Stephen Choi, operational savings specialist at Vancouver sustainability consultancy Panevo, for a list of actions industrial businesses can take to determine if their compressed air systems are being utilized efficiently.
Here are his suggestions:
1. Create an inventory of end uses to determine flow demand
"Walk through your plant and identify all compressed air end uses and if possible, flow and pressure requirements. Determine if the end use can be replaced with a low-pressure fan, blower or mechanical device, eliminating the demand for compressed air completely. If replacement isn't possible, make sure that equipment or area air supplies are automatically isolated when not needed.
"Using compressed air inappropriately not only wastes it at the point where it's used; it also increases overall system demand, which can lead to an increase in generation capacity. In many cases where inappropriate uses of air are eliminated, we also advocate a reduction in system pressure to match the end use specifications. For every 2 psi reduction in system pressure, you'll save around 1% of your electricity cost."
2. Establish an accurate air use profile for your compressor
"Compressed air generation is measured in cubic feet per minute or CFM. Understanding your flow profile is important because it relates to the suitability of your air compressor for a given application.
"It's especially important to note the peaks and valleys in demand and their duration. Once you know your flow profile requirements, you can optimize your compressed air system to suit your production needs. Often, an appropriately sized air receiver is all it takes to maximize efficiency."
3. Stage compressors for the most efficient scenario
"An air compressor that's undersized could affect production, but a compressor that's oversized can cost you in wasted electricity. During a recent operational energy analytics walkthrough of Vancouver Island Brewing's facility in Victoria, we observed through temporary metering that the overnight load was very small. We worked with facility staff to install a smaller 1 horsepower air compressor – about a $1,000 investment for the brewery – to service the off-shift loads rather than keeping the larger 34 horsepower compressor going all night. This small operational change is expected to save the brewery about 80,000 kilowatt-hours a year, equivalent of around $6,400* in annual savings.
* Based on a typical rate savings of $0.08/kWh. Rate is an example only and does not factor in taxes or net present value (NPV).