Please enter Your Name to link to your Design Journal, and paste a link to your personal folder on ACC in the ACC Folder Link field above.

This is my final design model, and I will introduce the step I took to get the following model.

For the base floor, I chose 10” concrete slab as the base because 10” is a pretty common base floor thickness. The base floor is the one that touches the earth, considering 10” thick concrete ground floor may not have enough thermal properties, I also included a 0.4” thick thermal insulation layer to keep the building warm in the winter.

I chose 3” LW Concrete on 2” Metal Deck for the 2nd level floor.

For the roof, I chose the EPDM deck as preliminary setting. I prefer the overlapping roof because it provides a good shade area of the building in the summer and prevents leak when the rain comes. Also, it takes less time to construct.

I opened a 45’ x 40’ shaft area up to the second floor as my atrium.

Glazing Wall: For the terrace, I designed a glazing wall for visitors to get better views. The glazing curtain wall let a lot of daylighting go inside the building. To let more daylighting goes into the building, the direction of this wall should be facing to the south. The properties are as following.

Brick Walls: I used Exterior-Brick on CMU for other exterior walls. The properties are as follows:

To be convenient, I set all location line as Core Face-Exterior in case for the later adjustment.

For the windows, I used Double glazing 1/4 in thick - green/low E (e=0.2) glass. This type of glass has very low emissivity, which means less daylighting will be reflected by the window. Although the price of this type of window may be a little bit expensive, the trade off is we can take more advantage of the passive design.

For the skylight, I used two pyramid shape skylight windows for the atrium because the atrium has a relatively large area, which means it will take more electricity for lighting. I want to take more advantage of the passive design analogy, so I increased the skylight area for the atrium.

For the space where we put a glazing wall, I didn’t set any skylight since those places already have sufficient daylighting income. For other places like offices, I think it’s a good idea to use more daylighting.

I considered green roof to take maximize use of the sunlight. The properties of the green roof is shown as following. The thermal mass is about 20.3 BTU/ft2F, which looks pretty good.

The shape of the green roof is as following:

I extend the roof area as my building shading. Usually, the south side of the building can obtain more sunlight than the north side. So, in case of the hot weather during summer time, I expended more roof towards to the south. Also, the mullion system can increase the shading area.

a. Plug Load Efficiency : 0.6W/sf

After setting the plug load efficiency to 0.6W/sf, the BUI value changed significantly to 95.7. To achieve this, it’s recommended to use higher efficiency plugs and reduce its working time.

b. Lighting efficiency: 0.3W/sf

For this design, since we added a lot of windows and glazing walls, it’s reasonable to take greater advantage of the passive design.

c. PV coverage and PV payback year

Since we already have the green roof part, so I just set the PV coverage rate as 60%-75%, and the payback year setting as 30 years.

d. Wall construction : R38 wood

For this part I set R38 wood as my wall construction option.

e. HVAC : High efficiency heat pump

It is worth to mention that the high efficiency heat pump is the most significant wat to reduce the EUI value.

f. WWR in each direction

For the window to wall ratio, I just set each direction less than or equal to the BIM value.

g. Other factors

After my observation, above are the most significant values that may change the building performance. Other factors do impact the final result, but they are relatively having much smaller change compare with above.

After adjusting the different factors mentioned above, the mean EUI value of this building dropped significantly to 35.6 KBTU/ft2/yr.

For the potential to the achieve additional improvements, I suggest to install some rain boxes to collect rainwater and use the rainwater to flush the toilet. By doing this, we can effectively increase the plug load efficiency to further downsize the BUI value.

Form the results listed above, they most significant factor to reduce the BUI value is the HVAC efficiency. By setting high efficiency heat pump, the EUI value can be reduced by 27.46 kBTU/ft2/yr.

Also, other key factors like PV payback year, PV coverage rate, plug load efficiency, lighting efficiency etc. are also making a significant contribution for reducing the building EUI value.

https://acc.autodesk.com/docs/files/projects/a1aab0b7-fb90-4335-b850-011955780722?folderUrn=urn%3Aadsk.wipprod%3Afs.folder%3Aco.6t42EHxPTgatT8V9JMWY4A&entityId=urn%3Aadsk.wipprod%3Adm.lineage%3AbjjLzor7Se2h6bRQY3H-NQ&viewModel=detail&moduleId=folders