That's a pretty big area. Do you need all that space?

You most likely need to be using the air flow to manage the moisture levels, especially since you're running a portacool, or you'll run into respiratory and fungal issues. You might be able to get around this with a dehumidifier and swirling the air flow with fans since you have such big space, but it's not really a replacement for fresh air.

Whatever you do, keep the space as clean and dry as possible.