2.7 Daylight Analysis - Scale Models
A scale model can be a useful tool in designing and confirming daylighting concepts.
The benefits of this method include:
- This 'hands-on' tool can facilitate understanding
- The three dimensionality of it can be easier to comprehend
- Depending on the model, some 'What If' analysis can be possible
- Unlike electric lighting, daylight scales well
- It may be the only method some customers will accept
When used indoors, daylighting models are typically studied with both an artificial
sky for the diffuse lighting and a heliodon for direct solar penetration.
Scale models can also be studied outside assuming calculations will be adjusted
for location, time and other variables.
Artificial Sky with Built-in Sun Simulator
In Fuller Moore's book "Concepts and Practice of Architectural Daylighting," a simple
tool is presented that can be attached to a scale model that is to be taken outside
to see the sun based shading that will occur for any time of day for any month of
the year.
The construction scale of a model for studying daylighting depends on the specific
needs of the model:
|
Scale
|
Goals
|
|
1:200 - 1:500
|
- For preliminary design and concept development
- To provide a gross sense of the massing of the project
- To study the shadow created by the future building or from a neighboring building
|
|
1:50 - 1:200
|
- To study direct sunlight penetration into a building
- To study diffuse daylight in a very big space like an atrium
|
|
1:10 - 1:100
|
- To consider detailed refinement of spatial components
- To have highly detailed inside views for video or photos
- To accurately study diffuse and direct daylight penetration
|
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1:1 - 1:10
|
- To integrate critical industrial components
- To consider daylighting devices that cannot be reduced in scale
- To proceed to final evaluation of advanced daylighting systems through monitoring
and user assessment
|
Some other considerations in model construction include:
Materials
- The walls of the model must be absolutely opaque, and all the joints must be light proof
- Model parts must be movable or replaceable to facilitate comparison of configurations and allow for the placement of sensors and cables
- Optical properties of internal (walls, ceiling, and floor) and external surfaces must be as close as possible to those of the planned building
- Model glazing materials, i.e., thin sheets of glass or clear plastic, should be used in apertures if the angle of incidence transmissivity of glass is expected to be important for the distribution of daylight in the internal spaces
- Geometry and sizes must be as accurate as necessary to permit consideration of the design questions
Other Criteria
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The overall dimensions and weight of the model must be such that it can be supported (e.g., on a heliodon) or moved (e.g., movable mock-up rooms)
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The size of the model must be reasonable with regard to the distance to light sources (e.g., 0.6 m in height for a 5-m-diameter sky dome)
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The attachment of the model parts should be strong enough to allow different movements (e.g., mock-up rooms) and even vertical positions (e.g., heliodon)
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Access to the model's interior, through apertures or removable parts, must be possible for placing illuminance sensors or imaging devices
Property of
