1. Kinetic Light-Shelf System
Mode A: Light-Shelf
Mode B: Vertical louver
This project is about the development of a kinetic shading system that can change its function according to the altitude of the sun.
1.Mode A. Light-Shelf (High altitude)
- Improving Indoor Daylight
2.Mode B. Vertical Louver (Low altitude)
- Blocking direct sunlight to prevent a glare
2. Research Background
2.1. Energy issue
According to US.EIA (2019), about 40% of total energy use is occupied by building sector. More than 50% of energy usage in office buildings is for heating, cooling and lighting.
2.2. Limitation of existing facade systems
Current louver systems such as horizontal, vertical louver system focus on blocking direct sunlight by considering the season and orientation. However, there is a limit to adapt to the daily sun's trajectory to perform conflicting functions according to altitude.
3. Transformable functions according to different altitude of the sun
Light-shelf
Vertical louver
4. Conversion process of the kinetic system
2-1. Design process of the Kinetic Light-Shelf System
Step 2.
Remove parts that is conflict with the adjacent unit
Step 1.
Arrange units in a line
Step 3.
Calculating the rotational ratio
between the vertical shaft and the light shelf.
In this case, the rotation ratio between the shaft and the light shelf has a 1:2 ratio. That is, when the shaft rotates 45 degrees, the light shelf rotates 90 degrees from horizontal to vertical to perform the function of a vertical louver.
The rotational ratio between the vertical shaft and the light shelf depends on the building's orientation.
2-2. Light shelf considerations
2-3. Vertical louver considerations
In order to perform properly as a vertical louver, the following conditions must be satisfied. When the light shelf is converted into a vertical louver, the spacing between the kinetic light shelf units should be considered so that direct sunlight from the side causing a glare issue does not penetrate into the room.
3. Prototype
3-1. Version 1 : Using Timing belt
Components of KLSU
110:Unit Frame
111: Rotation axis(y) for Unit Frame
121: Rotation shaft(x) for Light-Shelf
122: Light-Shelf
131: Roller for Timing belt
132: Rotating gear connected to Timing belt
133: Rotating gear connected to Light-Shelf
134: Timing belt
140: Rail for Roller
Step 2
3-2. Version 2 : Using bevel gear
Bevel gear part 1
Bevel gear part 2
Step 1
Step 2
4. Integration with a Curtain wall system
Light-Shelf
Vertical louver
5. Fabrication
A quarter-scale mock-up was fabricated using bevel gear. The small scale model was manufactured by the computer numerical control(CNC) tool using ABS resin material. The proposed system is operated automatically through the power supply (Gray box at the bottom).
Vertical Louver for East
Conversion Process
(Vertical Louver -> Light-Shelf)
Light-Shelf
Conversion Process
(Light-Shelf -> Vertical Louver)
Vertical Louver for West
6. Performance test of quarter scale Kinetic light shelf system
B (Lightshelf)
A (No_system)
A
B
6-1. Performance simulation(solar-ray) of different functions
7. Applying a photo-voltaic panel on the kinetic light-shelf unit
The double KLSU system is a kinetic shading device which has two rotatable panels. The upper panel works as a light-shelf like the existing single KLSU, and the lower panel serves as a PV panel for harvesting solar energy. The lower panel is designed to respond to different solar altitude by using a bendable rotation shaft.
8. Achievement
8-1.Patents
Patent1. https://patents.google.com/patent/KR101306640B1/en
Patent2. https://patents.google.com/patent/KR101736295B1/en?oq=KR101736295B1
8-2. Published papers
1.https://pdfs.semanticscholar.org/eeb6/c839bd09ba6607eb0e31afff155473dc7a15.pdf
2.http://journals.theired.org/journals/paper/details/5712.html
From Light-Shelf(High sun's altitude) To Vertical Louver(Low sun's altitude)