I decided to go with a Rooftop AHU system. I inferred that the North Zones would be most likely to need heating in the winter time and the southern zones (although shaded by the roof overhang) would need AC during the summer, I decided to implement a heating and cooling system to the respective zones. The whole system runs throughout the building, so I may need to go back and alter the heating and cooling assignment zones. The central zone (except restrooms) does not have heating and cooling assigned to it because it houses storage, elevator, stairs, and mechanical areas. Additionally, because it is in the center of my building, air will circulate via the occupants moving throughout the building. A challenge I encountered was properly connecting the ducts together. I see how people can spend extended periods of time perfecting the HVAC system.
Another difficulty I encountered was fitting the bigger ducts closer to the AHU in the area of the designated mechanical room. Having an architecture background and no prior knowledge of HVAC systems, I didn't realize they needed to be located generally close to the outdoors. I initially designed my building thinking the HVAC could fit inside the center core of the building. I resorted to compromising part of the rooftop deck to make way for the AHU system.
When modeling the Air based system for the 1st floor of my building, I went to each climate zone and adjusted the CFM airflow recommended for each zone. The rooms on the south side of my building required more CFM than the rooms on the north side. I chose to intentionally leave the HVAC system exposed as a feature of the building.
I tried using the system inspector but I don't think all of my ducts/terminals were properly attached as when I tabbed to select all of the supply ducts, it didn't highlight all of them.
When I used the system browser, I have 14 unassigned items. The goal of this unit however, is not to go back and make sure everything is perfect, but to gain a greater understanding of how to use systems in Revit.
A challenge to think about in my design would be to potentially add a ceiling plane to decrease the amount of volume in each space that is calculated into the overall heating and cooling load.