best is to blow the air OUT of the room, no need to pump in fresh air.
Sorry but thats not true , fresh air must be pumped to cool down the machines , it's a simple rule if there is exhaust there must be intake to fill the hot air pumped out with cool fresh air.
Wouldn't it make more sense to have the same amount of inout as output ? So the air moves in and out and stays fresh. Just treat the entire room as of to were a massive pc tower you inside of. Then you need to make sure the path the air flows is not restricted and is in the best place to maximize tempreture reduction.