Things to keep in mind when analyzing daylighting in AGi32

Accurate daylight analysis requires using the correct surface designation for exterior, but not interior, surfaces.

06/20/2013


The key to accurate daylight analysis using AGi32 is the assignment of the correct surface type designation to glazing and exterior surfaces. Interior surfaces require no special treatment. Daylighting calculations using AGi32 follow several important assumptions:

  • AGi32 considers the following daylight components: sunlight, skylight, and light reflected from a “virtual” ground plane.
  • Daylight can only be seen by an interior surface (interior of a room or object) after it has passed through a “daylight transition surface.” This is typically daylight transition glass.
  • All exterior surfaces must be classified as “daylight exterior surfaces” to accumulate daylight components.
  • “Daylight transition surfaces” will consider light reflected only from “daylight exterior surfaces.”
  • Daylight models must contain at least one “daylight transition surface” or “daylight exterior surface” in order to compute daylight component.
  • The virtual exterior ground surface is automatically assigned a reflectance of 18% (average reflectance of an exterior scene, by Eastman Kodak, circa 1904).  

With these ideas in mind, we can create any model, classify all exterior surfaces as “exterior daylight surfaces” and classify all glazing as “daylight transition glass.” All interior surfaces may remain single- or double-sided, as created using the room or object tools, or imported (imported surfaces become objects). 

Courtesy: AGI website (www.agi32.com)



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