Door unit for an air conditioning system, an air conditioning system, and a method for operating an air conditioning system

A door unit for an air conditioning system, comprising:

• a stationary and solid inner screen part,
• an outer casing part surrounding the inner screen part and having a first inlet opening and a second inlet opening, the outer casing part rotatable among different operational positions in relation to the inner screen part by rotation about a rotational axis of the outer casing part, and
• a flap member attached to the outer casing part,
• wherein, in a first operational position of the outer casing part, the flap member is positioned to allow passage of both a first flow of air from a first air flow channel upstream of the door unit and a second flow of air from a second air flow channel upstream of the door unit and separate from the first air flow channel into a third air flow channel downstream of the door unit,
• wherein, in a second operational position of the outer casing part, the flap member is positioned to block the first flow of air from the first air flow channel from entering the third air flow channel and allow the second flow of air from the second air flow channel to enter the third air flow channel, and the outer casing part is positioned to allow the first flow of air from the first air flow channel to enter an internal volume of the door unit via the first inlet opening, the internal volume being enclosed by the inner screen part and the outer casing part, and wherein the internal volume forms a fourth air flow channel,
• wherein, in a third operational position of the outer casing part, the flap member is positioned to allow the first flow of air from the first air flow channel to enter the third air flow channel and to block the second flow of air from the second air flow channel from entering the third air flow channel, and the outer casing part is positioned to allow the second flow of air from the second air flow channel to enter the fourth air flow channel via the second inlet opening.