Hello,
Can you post some general plan of the room that you are planning to use? Also important would be the number of miners you plan on using and also the main wind direction of your area related to your farm position.
 The main wind direction you can find by hanging a flag on the actual building.
With these informations, some of the forum guys can give you very good advice, and at those ambient temperatures that you have there, you might be verry succesfull with using natural air cooling for your room by only using some well-placed windows.
 Regards.