My overall HVAC system strategy was to design a decentralized, exposed air-based system with ductwork placed directly beneath my beam systems. I placed air handler units of different sizes in the mechanical rooms on levels 1, 2, 3, 4, 5, and 8 according to the varying loads on the different levels, with the handler unit on level 5 connecting to the ductwork on levels 5 and 6, and the handler unit on level 8 connecting to the ductwork on levels 7 and 8. I chose an air-based system based on similar buildings in NYC and to account for cooling, heating, and ventilation within the same system.
The biggest challenge I encountered was excessive cooling loads throughout the building, likely due to my attempts to maximize daylighting in my passive design strategies. Moving forward, I plan on implementing more robust shading strategies in addition to the triple-glazing on my curtain walls and the double-glazing on my windows. Also, because I had placed my mechanical rooms in different locations (due to my previous lack of knowledge on the layout of HVAC systems) I wasn’t able to design a centralized system, but this was less of an issue as I had already wanted to design a decentralized system due to the flexibility it allows (i.e., the office spaces will likely need different controls than the exhibition and learning spaces). Still, this emphasizes the need for more forward-looking strategies in the earlier stages of design. Finally, I found it difficult to properly integrate the ductwork into my overall floor plans due to my circular building form and the large required size of many of the ducts.
As I continue to strengthen my passive design strategies, I anticipate further refining my mechanical model to account for the lesser loads.
