I am wondering whether it is ok to vent the hot air from a portable air conditioner to the same duct where the bathroom air vent is in an apartment considering that the apartment block removes the supposedly humid air from all the bathrooms using a HVAC system in the building?
Sounds like great idea.
Probably should verify that the bathroom exhaust is exhausting directly to the outside.
Look up the AC output in CFM, vs the duct size, vs the exhaust fan size.
It sounds more complicated than it is to verify before proceeding.
Technically it should work, but esthetics of it (having a ugly pipe going to the ceiling) probably stoped others from doing it