The position of the lamellas in the ceiling adjustable diffusers type TD can be varied (horizontal, inclined or vertical airflow) in order to optimise the entry of air into the room during cooling or heating while meeting the necessary comfort requirements. The diffuser can be used in tall premises (e.g. workshops, airports, theaters, bank halls) as well as in lower spaces with a height more than 3,80 m, e.g. assembly workshops.