Don't forget to consider whether the compressors you're referring to will run during winter, and consider whether the chilled water loop/cooling tower will also be in operation during this time. You'll want to stick to an independent cooling method if you will run the compressors during winter...
Bright idea: Replacing pulleys on an AHU w/VFD. AHU normally runs at 67%, so I thought adjusting the ratio of drive to driven to put the motor closer to it's more efficient speed. Ok, increased the drive to driven by 20%. Motor speed is up to 76% (didn't go quite as far as I had hoped)...