Looks like you are using rotation to model your own fan.
Pressure drop is an equation goal based on the difference between the static pressure averages on the inlet and outlet faces. Those are done with surface goals.
The efficiency is another equation goal using the pressure drop equation goal as a parameter. If you go through the tutorials, you'll find a couple examples. I think it is the flow over cylinder one that has the equation goals.
If you are still stuck, let us know what you tried and where you get stuck.