On their submittal data sheets, elevator manufacturers list the CFM requirements of Machine Room exhaust fans, based on the HP of the elevator motor. To get air INTO the Machine Room, you will need a transfer air opening with a fire damper. To exhaust the air OUT of the Machine Room, you will need to run the fan discharge duct through the wall, with a fire damper. Instead of exhaust fan you could use a ductless split cooling system, but that is much more expensive.