The non-window models all LOOK as though they include a tall "bucket" about the size of a standard kitchen trash receptible. Also, the first such model I looked up included this notation:

"Direct drain option for continuous operation."

That would seem to imply that if you do NOT connect the unit to a "direct drain," you will have to occasionally shut down and empty some wastewater.

Perhaps the design allows most of the condensation to be recyled by cooling the coils, but it may be inevitable that some amount of water will eventually accumulate, even if it does so very slowly.

Installing a window unit can be a pain the butt, especially in a temporary situation. I'm sure that portable units like these can be a very attractive option even if a bit of occasional maintenance (nothing more than dumping a little water) is necessary.