Design Journal Entry - Module 7

Journal Entry For
Module 7 - Building Envelope Systems

My Model from three views

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1. Building envelope

Curtain wall

I used two types of curtain walls: Storefront, and edited storefront. The glazing type is double glazing ΒΌ in thick, blue-green/low-E (e = 0.2) glass. The first reason I use the curtain wall for my design is to introduce a lot of daylighting so that my electric lighting consumption will be relatively small. Another reason is to let visitors have a nice view since we have an atrium in the lobby, and visitors can look through the curtain wall to the roof and courtyard. For the curtain wall on the south side, I adjusted the panel distance to simulate it as a shade since the south side can have significant solar energy input. The south curtain wall has a vertical space of 5 feet and a horizontal space of 10 inches.

Curtain wall at north

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Curtain wall at south

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Curtain wall at courtyard

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Roof

I designed three types of roof: The main light color roof, terraces roof, and green roof.

My main roof has a R-value of 16.5 hr-F-sf/Btu

The yellowish main roof has a slope angle of 9/12 which has a nice solar angle for the PV system (I plan to install PV panels on south side of roof). More importantly, I installed several daylighting windows on the north side of the main roof (In this way, we can reduce the electric lighting in lobby, and people can have nice natural lighting every day.). Furthermore, the daylighting design on north side of roof cannot receive much solar energy since they are facing north.

My main roof

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Main roof input

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Terrace roof has a R-value of 16.5 hr-F-sf/Btu

The Green roof has a R-value of 2.07 hr-F-sf/Btu

For terrace roof at south, there may be a big problem since we have a lot of exhibit and conference room underneath. During the day, a huge amount of sunlight can cover the terraces, and the energy may penetrate the roof. However, we can design some additional feature, for example, sun umbrella, some PV panels, more importantly, the green roof (we can plant a lot grass or vegetation, even small tree so that the solar energy can be absorbed by the green plant). The green roof has a relatively low R value, but it has a large potential as a thermal mass. During daylighting, a lot of heat can be stored into plant, then they will release the heat to form a heat space between the earth and roof. In this way, we can prevent heat losses during winter.

Green roof and terraces

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Green Roof Input

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Doors

In my model, I installed three types of door: Double glass, Exterior-revolving-full glass metal door, and single flush door.

The exterior-revolving-full glass metal door were installed at back of building as a main gate, because the they can have a large capacity to take people and entry purposes. The double glass door were installed as exit at each side of building. I know it may be weird to design a glass door people exit, but it can clear indicate the exit. When fire happened or electricity break down, people can see the natural light from the glass door and exit. For security purposes, we can introduce a tint glaze to reduce the transparency.

The normal single flush was designed for inside use. Because my exhibit was designed as area show and there are no restrictions for people moving around. The single flush was only designed for office entry, restroom entry, and storage entry.

Double glass door

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Exterior-revolving-full glass metal door

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Single flush door

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Skylight

I installed seven sky lighting windows at north side of roof to prevent significant solar energy from south. The glass was used as simple normal glass, and I will conduct solar and lighting analysis to see if we need to use more expensive double glazing or low e window. We have a thermal conductivity of 0.63 btu/(hr-sf-F) (which is not very great if we have solar covers the daylighting windows). Nevertheless, we reduced a lot of electric lighting since our daylighting windows can cover most second floor areas, and part of first floor lobby (shop and cafe). In the future, if we can, I may install additional daylighting window on my terraces to introduce the daylighting into our deep first floor areas. More importantly, I plan to use the plant to shade the solar energy for that daylighting window.

Skylighting materals

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Daylighting Windows on north roof

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Daylighting geometries

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Shading

I designed a overhang at south side of curtain wall to reduce the solar energy. In addition, this overhang can also be used for the courtyard. In summer, people can sit there under covered by the overhang.

Shading for southern curtain wall

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Shading for small windows on east, north, and west

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Shading Materials

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For small windows on other side of wall, I used a daylighting shade. The shade can hide the sunlight for large portion of window, and reflect the light into room from small window.

2. Energy Model in Insight

The original model (inputted into insight without any changes), my building has a EUI 54.9 kBtu/sf/yr, which is quite meet my expectations, because I did not introduce too much curtain wall system. Hence, I can add more glass for my building to improve its aesthetic competitions.

Original Energy Model

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EUI of original model

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I adjusted the factors fours times:

  1. The origianl mdoel EUI
  2. Baseline EUI (I narrowed the operating schedule to BIM value, lighting efficiency at 0.3 W/sf, and plug load efficiency as 0.6 W/sf)
  3. Narrow down all factors to BIM values
  4. Narrow down the PV part (20.4% efficiency, payback year 30 years, and coverage 60%, because mo roof has daylihgting design, and green roof, courtyard, and some recreational space, therefore, 60% is very god value to start).
  5. The origianl mdoel EUI

1. The origianl mdoel EUI

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The EUI 54.9 kBtu/sf/yr is relatively acceptable since we have a lot of potential to reduce the energy consumptions.

  1. Baseline EUI (I narrowed the operating schedule to BIM value, lighting efficiency at 0.3 W/sf, and plug load efficiency as 0.6 W/sf)
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After setting the lighting efficiency, plug load, and operating schedule to certain values, I got EUI 31.7 kBtu/sf/yr which met the ASHRAE 90.1 requirements. I am quite glad that I can meet one of the requirement.

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  1. Narrow down all factors to BIM values

After I adjusted all tilts to BIM values, I got EUI 30.1 kBtu/sf/yr which is a little improvement. I found WWR southern walls, WWR western walls, WWR eastern walls, roof construciton (uninsulated), infiltration, and HVAC can affect the building efficiency significantly. Our BIM values are at mid of those ranges. From the feedback, I plan to reinforce the soalr wall (southern, eastern, weestern walls) insulation. In this way, we can reduce the enenrgy input. In addition, the roof insulation can also be introduced.

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Factors adjusted:

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4.Narrow down the PV part (20.4% efficiency, payback year 30 years, and coverage 60%, because mo roof has daylihgting design, and green roof, courtyard, and some recreational space, therefore, 60% is very god value to start).

If I add the PV system (longest payback, 60% coverage, and highest efficiency), I can get a very nice EUI of -6.4 kBtu/sf/yr. Even though I set the payback to 10 years, I can get 0.44 kBtu/sf/yr. Therefore, this means the PV system is key for our building, and we must cover the panels 60%. From this result, I may plan to reduce my vegetation areas for my panels

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Summary

Overall, I need to reinforce my wall insulation at east, west, and south. In addition, try to cover the PV system as much as I can (at least 60%). I will also adjust my daylighting design since the daylighting control did not have much impact for building in Insight.

Daylighting Analysis

First-floor lobby

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First-floor lobby

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Second floor space near the stairs

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Second floor space near the stairs

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Second floor space near office areas

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Second floor space near office areas

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The office area is quite dark actually, and I think I need to introduce more curtain wall. More importantly, this is the reaosn why my EUI is so low becasue there are not muc solar energy inputted into my second building. I can see the daylighting from my northern daylighting window. The second floor near the stairs is also dark in morning, and I may need to install side daylighting window to solve this dark problem. There is not any light penatrates the lobby, and I need to adjust the curtain wall position, and this is too dark.

Lighting Analysis

Due to the limited credits, the lighting analysis cannot show a very good view. Nevertheless, we can see our courtyard received a lot of solar energy and the east side of window. Becasue of daylighting shade, the light cannot go far. If the credits are available in future, I plan to view the daylighting situation for other time and space.

Top View

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Top View

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