@smith7162 asked this question:
In this diagram, the AHU is intended to be a ceiling-mounted, compact unit serving that zone, not a large central AHU in a mechanical room. It still functions as the central hub for air circulation and conditioning - it takes in return air and ventilation air, filters and conditions it, and supplies conditioned air back to the space while coordinating exhaust. In this arrangement, it is a smaller, distributed AHU, which is why it can be placed in the ceiling plenum. They still require maintenance (filters, coils, fans), which is why you’ll typically see access panels or service clearances designed into the ceiling.
Hope this helps!
Kiara Galicinao, AIA, NCARB
Product Coordinator
Black Spectacles