There are several types of air distribution systems used in air conditioning, including ducted systems, ductless systems, and radiant cooling systems. Ducted systems use a network of ducts to distribute cooled air throughout the building, while ductless systems use individual units to cool specific zones. Radiant cooling systems involve the circulation of chilled water through pipes in the floor or ceiling to cool the space. Each type of system has its advantages and disadvantages, and the choice of system depends on factors such as building design, occupancy, and climate.