All the portable units I've seen have had a tube, kinda like a dryer
vent hose, that you stick out the window (or up into the ceiling
plenum space) to vent the hot air. They generally "accidentally" leave
the hose out of the picture in the catalog. No way of getting around
the 1st law of thermdynamics, though. The heat has to go somewhere,
and it has to go outside the room for it to work.

> Now, with this all in mind, how do the portable room units work then?
> 
> They suck in the room air on one end, exhaust the hot air out the back,
> but seem to work pretty good.
> The condensation is either collected in a drain pan ( which has to be
> dumped every so often ) or is run out a tube to the outside somehow.
> 
> I wonder how they seem to work pretty good with re-using the hot air
> that is being blown out the back?
> Where does it go?