Hi- I'm looking for some ideas on what type of cooling system to choose for our cnc router machine that we are having built.

The spindles will run about a 90% duty cycle. The spindle bearings are a S1 rating. The spindles will run with only a break for lunch in a 8 hr shift.

Do I choose:
Fan cooled spindle?
A compressed air cooled?
A liquid cooled with a chiller?