don1
Funny you should ask? Atlas makes the first true vsd compressor, designed from the ground up. The savings are there. First off, you need to determine what it is costing you to operate your current machine. There is is a standard formula for calculating that. Next, you need to develop a load profile for your system. This is a little more involved, Atlas Copco distributors have access to a device called a motor box, which will monitor your operation and determine your patterns of usage. With this information in hand, that can be downloaded into a software program (also provided from Atlas) to develop a stratagey for savings.
You may add tanks, use a smaller machine as base load and trim with a VSD or simply run a VSD. It will handle alot of different scenarios to determine if ther are savings to be had.
By the way, if you haven't figured it out yet, I work for an Atlas Copco Distributor.
Please feel free to contact me anytime.
Dilligaf