No, you do not need a fan to use a portable air conditioner. Portable air conditioners are self-contained units that are designed to cool the air without requiring an additional fan. They work by pulling warm air from the room, passing it over a cooling coil to remove heat and moisture, and then releasing the cooled and dehumidified air back into the room. The warm air is typically vented out of the room through a hose or window kit.
Some portable air conditioners may have built-in fans to help distribute the cooled air more effectively, but these fans are part of the air conditioner itself and not separate components that you need to provide.
However, it's worth mentioning that using a portable air conditioner in a well-ventilated room can improve its performance. This is because the warm air exhausted through the hose needs to be replaced with fresh air from the outside to maintain efficient cooling. Having a window or door partially open can help with this ventilation process. Some people use fans near the window or door to assist in bringing fresh air into the room, but this is not a requirement for the portable air conditioner to function.