Most industrial users of compressed air experience fluctuating demand for compressed air. Variable Speed Drive compressors are designed for these users. Using a VSD compressor makes sense when:
Demand for compressed air fluctuates significantly between jobs
Demand varies by shift, on weekends or seasonally
Manufacturing processes require tight tolerances for operating pressure
These examples all relate to air pressure, so let’s look at some reasons why VSD offers advantages:
A VSD compressor can operate within a much tighter pressure band than a fixed speed compressor can attain.
A VSD compressor can operate at lower delivery pressures and still maintain the air system’s required minimum working pressure.
A VSD compressor’s net pressure can be set lower than the unloaded pressure on fixed speed compressor, and each 1 bar reduction results in 7 percent savings in energy.
A VSD compressor delivers more consistent discharge pressure for all the compressed air applications throughout your facility.
Using VSD and fixed speed compressors together
Sometimes, the most efficient compressed air solution combines one or more fixed speed compressors to provide the base load with one VSD compressor that “trims” to meet changes in demand. A system with multiple smaller compressors instead of one big compressor also provides redundancy that allows you to keep part of your facility operational when a compressor is offline for service or repair.
Not always the best solution
VSD compressors do have many advantages that can benefit most industrial users, but they are not always the right choice. If your demand variations are minimal, a properly sized fixed speed compressor may be more efficient. Fixed speed air compressors cost less up front. However, when demand varies, the additional investment for a VSD compressor typically pays for itself through energy savings. The payback period can be accelerated with financial incentives from your electric utility.
The optimal design of a compressed air system will reflect the specific needs of your processes, your facility and your approach to capital projects. To learn more about how Variable Speed Drive can address your needs, talk to an air system professional.