Your building envelope recommendations for this practice exercise should feature:
- Your recommended settings for the Insight Factor tiles
- A screenshot from Insight showing the Predicted Mean EUI and the range of values resulting from your assumptions
The provided model generated an energy model that predicted a mean EUI of 81.2 kBtu/ft2/yr.
Changing the Insight Factor tiles of Operating Schedule to 12/5 and Roof Construction to R38 yielded a Predicted Mean EUI of 60.2 kBtu/ft2/yr.
Building Envelope-Related Design Decisions.
I changed the following tiles to find a combination that yielded a Predicted Mean EUI of 52.1 kBtu/ft2/yr:
- Wall Construction to R38 Wood
- Brought the mean to 59.3 kBtu/ft2/yr
- Window Shades East to 2/3 Window Height
- Brought the mean to 58.3 kBtu/ft2/yr
- Window Shades West to 2/3 Window Height
- Brought the mean to 57.6 kBtu/ft2/yr
- Window Glass South to Trp LoE
- Brought the mean to 57.5 kBtu/ft2/yr
- Window Glass North to Trp LoE
- Brought the mean to 56.6 kBtu/ft2/yr
- Window Glass West to Trp LoE
- Brought the mean to 54.9 kBtu/ft2/yr
- Window Glass East to Trp LoE
- Brought the mean to 52.1 kBtu/ft2/yr
By adjusting the building envelope-related designs, I found that changing the window glasses yielded a large decrease in energy usage, especially on the East and West sides. I also found that changing the WWR on the North and South would only result in either no change or an increase in energy usage.
Power and Lighting Measures.
I returned the model to the baseline specifications then adjusted the following power and lighting measure to get a Predicted Mean EUI of 40.7 kBtu/ft2/yr:
- Plug Load Efficiency to 0.6 W/sf
- Brought the mean to 50.3 kBtu/ft2/yr
- Lighting Efficiency to 0.3 W/sf
- Brought the mean to 41.7 kBtu/ft2/yr
- Daylighting & Occupancy Controls to Occupancy Controls
- Brought the mean to 40.7 kBtu/ft2/yr
I found that adjusting plug load efficiency lighting efficiency causes a great difference in energy usage. Adding in daylighting controls has no effect, but adding in occupancy controls has some effect. 40.7 kBtu/ft2/yr was the lowest I could drive the Predicted Mean EUI.
Adjusting the following factors to add PV panels to the design from above got a Predicted Mean EUI of -1.15 kBtu/ft2/yr:
- PV Surface Coverage to 90%
- Brought the mean to 37.9 kBtu/ft2/yr
- PV Panel Efficiency to 20.4%
- Brought the mean to 27.4 kBtu/ft2/yr
- PV Payback Limit to 30 years
- Brought the mean to 19.2 kBtu/ft2/yr
- Adjusting this tile affected the panel efficiency tile, causing the Predicted Mean EUI to go to -1.15 kBtu/ft2/yr
I found that adding large PV Panels and increasing the payback limit yields a great decrease in Predicted Mean EUI. Panel efficiency yields a slight decrease. -1.15 kBtu/ft2/yr was the lowest I could drive the Predicted Mean EUI.