Indirect Lighting & Energy Conservation Part 4

Category: Environment & Green Technology Published: Monday, 25 April 2016


Skylight Tube is a highly reflective, cylindrical skylight, that runs from the roof down into a room providing the illuminance of full spectrum lighting. Sunlight enters the tube through a clear acrylic dome. The inner prismatic lens (“fly-eye”) captures the light from all angles and collimates it down the reflective tube, to be evenly spread through out the room via a second prismatic diffuser lens. On sunny days, the Daylight Tube can provide the equivalence of 738 Watts of incandescent light. Even on cloudy days, the Daylight Tube can provide 100 to 180 watts of illuminance. 


It includes two-axis, tracking parabolic dish, light collection systems. as, the sun's position relative to the earth changes constantly. It is important to note, however, that the spatial illumination variability inherent to conventional topside daylighting throughout the day is eliminated in hybrid systems because the light will always emerge in the room at the same place traveling the same direction. Temporal variability will be minimized because hybrid luminaries will continuously adjust electric lighting based on the amount of sunlight available. 


Once collected, there are following several options existing for transmitting light to the interior of buildings. 

  • 2.6.a Large-core optical fibers – They are wave guides that transmit light via total
  • internal reflection and are typically fabricated using flexible materials such as solid
  • polymers, gels, and liquids. 
  • 2.6.b Fiber optic bundles –They are a series of small glass or plastic optical fibers
  • bundled together to form the equivalent of a large-core optical fiber. 
  • 2.6.c Hollow-core reflective light pipes – They are hollow light pipes that are typically
  • cylindrical in shape and coated with a highly-reflective material to transmit light via
  • multiple reflections off interior wall surfaces. Because of their flexibility, cost, ease of
  • installation, and performance, early hybrid lighting system designs in corporate largecore
  • optical fibers.