You can, but then you have to carry the full boiler with the hot air to the door by hand every 90 minutes and empty it.

Seriously, where is the heat supposed to be transported to if it cannot be dissipated via the exhaust hose? It's not as if the heat that the unit takes from the room simply dissipates. The heat has to go somewhere. With this type of air conditioner, it has to go outside via the hose.