Basics of Daylighting in a Green Environment
The use of natural sunlight, known as daylighting, to illuminate a building can save energy, reduce operating costs, create visual appeal, and enhance occupant health and productivity. The U.S. Green Building Council Leadership in Energy and Environmental Design (LEED™) rating system encourages the use of daylighting to achieve high performance buildings. This course provides an introduction to the use of daylighting in commercial spaces. The course objective is to show why daylighting should be considered, the basic guidelines of using daylighting and some words of caution when using certain daylighting techniques.

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
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

  • 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)
  • 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)
  • 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)
  • Access to the model's interior, through apertures or removable parts, must be possible for placing illuminance sensors or imaging devices

Property of

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