NCEUB Conferences, 13th International Radiance Workshop 2014

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Electrochromic / Tinted Glazing: Modelling the Illumination Spectrum
John Mardaljevic

Building: Arup 8 Fitzroy St.
Room: Emmerson & Shears Room
Date: 2014-09-02 04:30 PM – 05:00 PM
Last modified: 2014-08-30


The dynamic control of daylight has been called the "Holy Grail" of the fenestration industry. Electrochromic (EC) glass is believed to be the leading contender in the race to manufacture a glazing technology that will achieve this goal. With recent investment in the scaling-up of production capacity, EC glass is now set become a mainstream glazing product. As EC glass darkens ('tints') the peak in the spectral transmittance curve shifts to the blue. Thus the question regarding the neutrality of the illumination spectrum is an important one that needs to be addressed. In this presentation the author show that it is possible to maintain an effectively neutral spectrum of daylight illumination in a space with EC glass in normal operation, provided that a relatively small proportion of the glass is left in the clear state. The model for the illumination spectrum resulting from a combination of clear and tinted (EC) glass is verified by measurements with supporting Radiance simulations. The findings suggest that, in many practical situations, it may not be necessary to explictily model the spectral transmission properties of clear and tinted glass using lighting simulation.