It may be possible, but we’ll need a little more information…
Turning the fan on/off is easy. Just use one of my EX_Switch devices. Connect a relay to the digital output and then connect the fan to the relay dry contacts to turn power on/off. Obviously, the Arduino cannot supply enough power to run the fan at the correct voltage/current. That is what the relay is for.
As for adjusting the dampers, that depends greatly on what type of signal the damper expects? The Arduino does not have a true Analog Output which would vary voltage from say, 0 to 5 volts. The Arduino’s “AnalogOuput” routine is used to generate a PWM output signal. I am sure you could add a true analog output chip to the Arduino, but then you’re going to need to write some code to integrate it.
Sounds like an interesting project.