To figure out the HVAC System in my buildings, I needed to run an HVAC Load report to capture the peak loads for cooling and heating. For the HVAC Load report, I set the energy setting to match as closely as possible to the materials I selected in Module 7. Below are the analytic constructions I picked to model the load report on.

I had assigned an HVAC zone to each room in the building (except for the maintenance room and elevator shaft). Each zone was assigned to an air system and zone equipment. For cooling coil, I picked a direct expansion against chilled water to simplify the design (would not have to design water loop). For heating coil, I picked a furnace because my HVAC system was an air-based ducted heating.

Air System:

Zone Equipment:

In the load report, for each zone, it gave me the peak loads for cooling and heating. Using those peaks loads I calculated how much supply airflow is needed in each room based on the cooling loads because cooling load is larger than peak heating load. By using the peak cooling load, the baseline airflow and more will be provided. The calculated supply airflow was calculated by dividing the peaking cooling loads by 80 Btu/hr. Then, I calculated the actual supply airflow based on air terminals with a limit of 500 CFM. If a room required more than 500 CFM then another terminal needed to be added. However, if it was less than then I can change the terminal to fit the needed CFM.

For each floor, I had installed a 30,000 BTU Horizontal Split System Air Handling Unit to supply and return the air. Each 10”x20” duct was connected to a 24 x 24 Supply/Return Diffuser. For the duct system, I created a 2’ foot spacing between the flooring and the ceiling. This would allow room for the duct and air handler to be situated without ruining the interior of the building. The height of each floor was 15’ and the ceiling sat at 13’. The supply duct was situated at 13’ 6” and the return duct was placed at 14’ 6”. This allowed the ducts to overlap without intersecting each others place. I was able to have more freedom in deciding the path of the ducts.

Some challenges I faced design the HVAC system are the ceiling placement and mapping the ducts. Initially, I had designed a 1’ 6” ceiling space for the HVAC system but I realized that there wasn’t enough room for the air handler. So I had to go back into my architectural model and lower the ceiling height to achieve the 2’ spacing. Also, I had to lower the interior walls to match the ceiling so that there wouldn’t be any obstruction for the ducts. Having foresight into design all these components when I was designing my architectural model would have been helpful.

Second, mapping the ducts to avoid certain areas in my building. I wanted to avoid the elevator shafts, courtyard, and staircases. However, my maintenance room was right next to an elevator shaft, so I had to orient the duct in a weird angle.

Third, the cone roof was difficult to map the duct system because I wanted there to maintain the cone shape inside the building. But it was to difficult to map the duct system and try to hide it when there was no roof as a cover. So, I placed a roof about ~5’ about the floor height and drawing the roof at that elevation was tricky to figure out. I had to use different elevation views to get the right size.