Old A/C used RG12 New ones are different
An air conditioner in a RV uses refrigerant to chill air passing over an evaporator coil. The most common refrigerant is Freon and is easily found in most autopart stores.
The energy used is electricity.
It is just a simple fan blowing over a coil.
It depends on year of manufacturer.
R134a
The evaporator coil condenses the humidity in the air dehumidifying it.
R-134a
Turn it off and leave it off for an hour or two
You probably have mold on the evaporator coil.
The evaporator coil is probably freezing up which will restrict airflow.
Water dripping on the front of a portable air conditioner could mean that the air filter needs to be changed. Your evaporator coil may also be dirty.
Most of the ones that I have seen have dirty condensor coils. That's the coil you see from the outside. They get dirty on the inside of the air conditioner where the fan blows air through it.