HVAC Overview:
I decided to go with all air based heating and cooling as this is common construction in the development area and I thought it would be a good challenge to plan all the ducts. The HVAC network is split into six distinct zones across the entire building: Lower West Zone, Lower Central Zone, Lower East Zone, Upper West Zone, Upper Central Zone, and Upper East Zone. By separating the ducts and air handling units (AHUs) into these zones, the building can better control needed air flow based on the positioning of the sun. This will allow the building to be more sustainable and smart with heating and cooling allocation. The 1st (lower) and 2nd (upper) floor plans are below:
Floor 1 Plan:
Floor 2 Plan:
All ducts run to the mechanical rooms on the east and west sides of the building. Central zones have an AHU in both the eastern and western mechanical rooms, while the west zones have AHUs only in the western mechanical rooms and the east zones have AHUs only in the eastern mechanical rooms. I had to update my architectural and structural models to move the mechanical rooms to the exterior of the building. This allows them to more easily get new intake air. Below is an image of the mechanical system and architectural exterior. I added louvers to allow new air intake.
While designing the HVAC duct height, I checked to lower it below the structural elements. I initially want to slant the ducts with the ceiling, however, decided against that as it would severely complicate the placement of components.
General HVAC System Characteristics:
Air Terminal Height from Level: 12’ 4”
Supply Duct Middle Elevation: 15’ 2”
Return Duct Middle Elevation: 13’ 5 1/4’
*Duct height is restricted to not exceed 20”
I made an analytical model of the building to better understand the heating and cooling needs of each room. The space schedule and analytical schedule below show the key findings of this model. I kept track of specified and actual airflows as I went to ensure accurate sizing of the air terminals and vents. In many cases, I purposely oversized the air terminal and venting needs by a safety factor of 10-20%. I used the duct sizing tool to better understand the HVAC needs and satisfy them.
Throughout this process, I was faced with a couple key challenges. Firstly, while designing the analytical model, I faced challenges getting the spaces to align properly to their actual volumes, however, through trial and error was able to create it accurately. I found that by deleting spaces and replacing them, I eventually resolved the issues. Secondly, I reached challenges connecting the HVAC ducts to the AHUs within the mechanical rooms. In retrospect, I wish I would have made the mechanical rooms larger or split AHUs more evenly across the building. Thirdly, while designing the supply and return duct systems for each zone, I would lose track of vent as they got blocked in view by others. I constantly played with the hide element tool to juggle around this.
I reviewed the model coordination view and was satisfied with my results. I can see more so how these building reflect biological systems; the ducts remind me of veins throughout the body. I did a decent job combining the architectural, structural, and HVAC models without major collisions. If I had more time to work on this, I would change the venting to better follow the walls of the space. I would also match it to the slope of the roof and further plan ceiling options between the structural/HVAC and the public spaces.
