Thanks for the paper @aishanuraaa
I ran a design space over the weekend to explore the topic and test the approach of using Honeybee to quickly explore common questions. Anyone can review the results here:
http://tt-acm.github.io/DesignExplorer/?ID=aHR0cHM6Ly9kcml2ZS5nb29nbGUuY29tL29wZW4/aWQ9MVVCdGRRRnM0NExOMTIwc3MxVkFkNEhLMWluZWxDWDFM
Parameters Tested
- Façade type
- Full curtain Wall
- Ribbon window with lower portion solid
- Punched Window
- Location
- Detroit (cloudy)
- Phoenix (sunny)
- Clerestory Height (light shelf height from top of window) (3x)
- Clerestory Depth (4x)
- Orientation (8x)
It appears that light shelves reduce overall annual daylight levels. This apears to contradict the common idea that light shelves bounce more light farther into the space. However, this model does not incorporate internal blinds. As shown in the study @aishanuraaa linked, when light shelves block overlit conditions and allow blinds to remain up, overall light levels may increase relative to the shades-down condition. Light shelves therefore may still be an effective solution for improving daylight quality even if they do not on their own increase daylight quantity.
Taken from the conclusion of the paper:
“The findings concluded that the integration of light shelf and partial blind at sitting position eye level is the most effective design for contemporary high-rise open plan office. Therefore, internal shading shall not be overlooked or simply left to the office users to install without proper understanding in daylighting. Architects and interior designers shall take internal shading into thorough considerations even during the early design stage towards achieving effective tropical daylighting.”