Digital Design Simulation & Analysis Lab Exercise 2.
Group 5 Ramkumar A0123482 Chen Peng feng A0097794 Ng Wee Chai A0113005
Aim To achieve minimum glare/direct sunlight and allow maximum natural light/indirect sunlight into the space through Sun Shading Device and Skylight in normal Office condition.
Introduction The use of light balancing solutions to help achieve optimum comfort for occupiers is crucial as it optimises indoor comfort and saves energy. As a source of illumination, daylight is absolutely free of charge but it also has disadvantages as bright sunlight can cause unwanted glare and raise a building’s temperature both of these reduce comfort levels. The aim of this report is to provide the solutions by analysing the room space based on DIVA for Rhino Simulation Software. ➔ Firstly, to examine with different depth of sun shading devices in order to minimise glare/direct sunlight and maximise the natural light/indirect sunlight into the interior space. ➔ Secondly, to introduce Skylight in order to balance the interior lighting condition with less stark contrast of daylighting in the office room condition. ➔ In parallel, material types were assigned specifically for the skylight to prevent glare/direct sunlight entering.
Preparation of the analysis
Figure 1. Rhinoceros Model
A simple room (8x6x3m) with a southfacing window (with the glazing ratio of 0.75) and a surface (ground) at the foot of the south wall was created.
Daylight Materials
Figure 2. Material list
Materials were assigned specifically to the surface type and the weather file of Singapore was used as the location of the project.
Preliminary Analysis : Different depth of Sun Shading Device Width (m)
Louvres profile
Room profile
0.00m
0.075m
0.15m
0.30m
Figure 3. Louvres profile
The material for sun shading louvres is metal. This is achieved by designing appropriate shading devices with three different depths 75mm, 150mm and 300mm. These shading are laid horizontally with 200mm interdistance.
Preliminary Analysis : Different depth of Sun Shading Device Width (m) Description
Daylight Factor
0.00
Mean Daylight Factor = 5.46% Mean Illuminance = 800.06 lux
0.075m
Mean Daylight Factor = 3.82% Mean Illuminance = 620.80 lux
0.15m
Mean Daylight Factor = 2.90% Mean Illuminance = 516.68 lux
0.30m
Mean Daylight Factor = 1.94% Mean Illuminance = 393.19 lux
Illuminance
Figure 4. Daylight factor & Illuminance
The table (Figure 4) shows the comparison between the default model (the window without louvre) to 3 different depth of Horizontal system louvres (0.075m, 0.15m and 0.30m respectively) to determine the optimise daylight level of the room by comparing the difference in Mean Daylight
Factor and Mean Illuminance. In Mean daylight factor the percentage and mean illuminance lux level decrease significantly when the depth of the louvres increases. Although the daylight factor and the mean illuminance of 0.30m louvre illustrate a better light balance with less stark contrast of daylighting, the interior is gloomy(refer to figure 5). In order to achieve a normal office condition of 500 lux (refer to figure 6), 0.15m louvre may seems to be better choice. However, there is still a distinct contrast of illuminance in the interior (shown in figure 4).
Figure 5. Daylight Factor Table
Figure 6. Illuminance Table
Second phase Analysis: Skylight We introduce skylight to balance out the contrast of illuminance in the interior.
Glass (North‐south facing)
Glass (all sides) Adding glazing on all sides of the skylight and analysing the impacts
Adding glazing only on Northsouth facing of the skylight
Skylight Profile
Skylight Profile (Section)
Material
0.15m Louvre Timelapse
0.30m Louvre Timelapse
Figure 7.
By adding glazing on all sides of the skylight causes direct glare that cast into the space especially on 9am, 5pm and 6pm (shown on the left column of the above table). It is due to the sun path of east to west. Thus, by assigning the materials according to the specific position helps to resolve the harsh light that entering from the skylight. Solid surface material such as generic interior wall
finished are assigned to the east and west sides of the skylight to block of the direct sunlight and the north and south sides of the skylight are using the lowe single glazing (shown in the section figure 8) in order to prevent the daylight factor and illuminance level from increasing.
Figure 8. Section of the normal office room with skylight system
The envelope in Figure 8 is constructed using Low E Glazing and Single Glazing with 300mm diffused Metal Louvre. This customized louvres and skylight shows the optimal day light entering into the interior as it received more diffused light than direct sun light.
Comparison between 0.15m & 0.30m louvres with/without skylight Scale
Description
Daylight Factor
0.15m (without skylight)
Mean Daylight Factor = 2.90% Mean Illuminance = 516.68 lux
0.15m (with skylight)
Mean Daylight Factor = 3.34% Mean Illuminance = 782 lux
0.30m (without skylight)
Mean Daylight Factor = 1.94% Mean Illuminance = 393.19 lux
0.30m (with skylight)
Mean Daylight Factor = 2.36% Mean Illuminance = 671.5 lux
Illuminance
Figure 9 Daylight factor & Illuminance
In comparison, 0.15m louvre may seems to be better choice for achieving the normal office lux condition. However, 0.30m louvre demonstrate a better daylighting balancing inside the interior space. After adding skylight system , the choice of achieving minimum direct sunlight and
maximum indirect sunlight become more obvious. The contrast of illuminance in 0.15m louvre (with skylight) has become more distinct which causes the visual discomfort and artificial lights may require to install on the northern area. 0.30m louvre (with skylight) portray a better solution to our objective of resolving minimum glare/direct sunlight and allow maximum natural light/indirect sunlight into a normal Office condition.
Conclusion In this report, we have managed to optimise the sun shading design for the opening through 2 steps process. Firstly, we determined a horizontal louvres system offers a more uniform light, then through different permutation of louvres depth, we have identified 0.3m depth of louvre is the optimal sun shading device which can provide enough diffused lighting and visual comfort to perform the regular office tasks. Secondly, after introducing the skylight to achieve the balance of daylighting inside the interior space. Although we have achieve our objective, to conclude this model with a good balance between lighting and thermals aspect, daylight factor of thermal comfort may needed to further investigate with the tools of “ladybug and honeybee”.