I think air conditioning can't solve your problem. It matters the circulation of the air so you should add two fans. One of them should add the air into the room with rigs and the other one to take the air out. On the first one that brings the air into your room you should put some net to protect from insects. There is no need to be worried about the moisture because your rigs will dry it out.
What are you smoking? No need to be worried about moisture? Rigs will dry out? You have no idea what you are talking about. What exactly is it that you think an a/c unit does? It has two fans. One blows supply air across a cold evaporator coil and the second one sucks air in and blows it across the condenser coil to push heat from the refrigerant to the atmosphere. That heat was removed from the room.
The only problem lies in an a/c unit that is not big enough to keep up with the heat load of the miners. Then theres the power costs of the a/c to take into account.