Research Output
A design tool for predicting the performances of light pipes
  Light pipes are simple means of directing daylight (diffuse and direct light) into interior spaces. Previous work by the authors described the initial work on a luminous flux and illuminance predictive model for straight light pipes, using a basic equation for illuminance distribution as a function of horizontal distance. Further work has now produced a model that uses the cosine law of illuminance to describe the distribution of light from the light pipe diffuser as well as takes into account pipe elbow pieces or bends. The resulting illuminance model can be described as a quartic cosine model. By producing a “luxplot” prediction for any given light pipe application, it is possible to maximise the potential of these daylight providers and design their configuration to suit any given need. As part of this study, wide-ranging illuminance and luminous flux data were collected both for the formulation of this model (as the formula is semi-empirical) and its validation.

  • Type:


  • Date:

    23 November 2004

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  • Publisher

    Elsevier BV

  • DOI:


  • Cross Ref:


  • ISSN:


  • Library of Congress:

    TJ Mechanical engineering and machinery

  • Dewey Decimal Classification:

    621 Electronic & mechanical engineering


Jenkins, D., Muneer, T., & Kubie, J. (2005). A design tool for predicting the performances of light pipes. Energy and Buildings, 37(5), 485-492.



Light pipes, daylight, modelling, lighting

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