If you get a small 30 pint dehumidifier, you can turn it into a baby DIY mini split. Perfect size for a small 2x2 sealed tent in a room setup. You'll also need to supplement co2, so expect to get a regulator and bottle.
Preferably get a free or cheap used dehuey that is passed the warranty, because you'll be voiding it when you take it apart to modify the coil. Basically, you just take the front housing or plastic case off the dehuey, and carefully bend the evaporator coil out and away, without cracking or kinking the small copper lines and releasing all the freon into the air. If that happens you SOL, and need another unit.
Then simply cut a slit in the tent wall, and stuff the coil through it, and seal it back up around the copper tubes. Its literally that easy, as long as you are somewhat handy, or good at ghetto rigging or tearing apart shit at least. People still do it all the time to make affordable DIY glycol chillers, but in your case you would use it like a compact mini split unit instead. You just poke the coil in the tent, instead of plunging it into a cooler with glycol or a res...
You can also use a window AC the same way, but you don't need that many btus and it will be bulkier sitting next to the tent. Dehueys are more compact and easier to do the mod anyway..
Its the only way I can see that would be worth using HVAC to cool a small tent, without wasting loads of power and trying to condition the whole room.
