Interior view of merged model from Model Coordination showing the HVAC elements
Ground Floor Plan View HVAC Layout
First Floor Plan View HVAC Layout
Space Schedule Overview
Description
Design Strategy:
When exploring the available space, I noticed that the ground floor ceiling height is lower than the first floor ceiling height. This is due to the first floor slab thickness reducing the overhead space (the 12’’ floor level is to the top of the slab). After linking in my structural model from Exercise 8.5A, I decided to model the supply air ducts at 8’ 11’’ lower end bottom elevation on the ground floor, and 9’ 6’’ on the first floor. To avoid clashes between the two duct systems, my return air ducts are placed below the supply ducts, at 7’9’’ and 8’2’’ lower end bottom elevations respectively. While 7’9’’ clearance provides more than sufficient headroom for occupants, in future projects I would like to optimize this further, by having the ducts run parallel at the same elevation, and only drop the elevation underneath at the crossing points (in areas of low traffic).
The mechanical model provided passed the accuracy check, with ll spaces correctly assigned. I did, however, adjust the ‘number of people’ calculated per room for a few spaces that I felt needed adjusting. For example, the original design anticipated 90 people in the cafe, however with only 4 tables and 16 chairs, paired with the size of the building eand expected occupancy of surrounding rooms, this was far to excessive. Similarly, the design anticipated 0.5 people per office space, which I increased to between 1 to 1.4 people which I believe better fits the role of the building.
I adjusted the supply and return airflow of the different diffusers to best match the calculated requirements, without overengineering the building (thus saving costs and reducing the buildings EUI). I believe my design now meets the project’s spatial design goals.
Challenges Faced:
As with most design tasks, the biggest challenge was coordinating the HVAC design around the existing structural and architectural designs. Initially, for example, I had placed a duct running across the skylight opening.
Furthermore, maximizing the vertical space in the building is a further challenge I struggled with. Widening the ducts, and having them run at the same elevation (and only dropping the elevation at crossing points) are strategies I would use in future projects, to maximize available headspace.
Recommendations:
- Intall aesthetic ceiling/panels under the vents to hide them from occupants
- Minimize distance travelled by ducts, thus reducing the material use
- Minimize duct distances and bends, to maximize efficiency and thus reduce the power used to ventilate the building
- Install passive heating and cooling measures to reduce the design load of the HVAC system. Thes include features like:
- Passive solar heating
- Natural daylighting
- Window shades / mullions
- High insulation
- Natural ventilation