With thanks to Fort Fiends member Total Joker...
"Air-conditioning a tent, what I have learned....
1. You need a tent that can be sealed as much as possible, (to hold in the cool air).
2. As soon as you open the door, ALL the cool air is gone!!! (theres nothing in a tent to get cold)
So, now the fun stuff...
best and cheapest way to go is a window unit like this
The unit is outside the tent, "gives you more room inside" and the cost of the unit is alot better than a portable unit.
You can get a NEW 5K unit for $99 or less. And to make the cold air intake and exhaust use cardboard boxes, dryer hose and lots of duct tape.
You need to make a cold air intake and exhaust hose setup for the best results. Also you will need something to set the a/c up on to get it off the ground, a couple bricks or pieces of 2x4 will work.
Or you can get a portable unit like this...
This unit sits inside the tent, has a exhaust hose that comes with it "to exhaust the hot air", but the intake for the hot air is
inside the tent. So it is constantly pulling outside air into the tent. You will need to make a hot air intake setup to run outside the
tent. Again cardboard, dryer hose, and duct tape! Another little problem is the a/c makes condensation. You have to dump the pan in the unit once a day to keep it from running over make a puddle.
This is a pic of the "hot air intake" setup I did for mine.
Then you just run the hoses in or out of the tent."