Subjective assessment of visual comfort in a daylit workplace with an electrochromic glazed façade

S Jain,J Wienold,C Karmann

doi:10.1088/1742-6596/2042/1/012179

S Jain, J Wienold + Show 1 more

Open Access

https://doi.org/10.1088/1742-6596/2042/1/012179

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Abstract

Electrochromic (EC) glazing is increasingly employed in building façades to achieve better visual comfort for the occupants. EC glazing can modulate the light entering through the façade by varying the solar transmittance of the glass and therefore can work as a shading strategy to minimize solar heat gains or glare. However, it also alters the spectrum and distribution of light entering through the façade, which influences certain visual attributes associated with a space. This user assessment study evaluates some of these attributes including the colour perception of the elements inside and outside the room, the uniformity of daylight distribution, the clarity of the view through the glazing and the perception of glare when the sun is in the field of view. Results indicate a visual transmittance (τv) of 0.6% is sufficient to control glare when the sun is in the peripheral field of view (FOV) while τv,n-n of 0.14% is required to control glare when the sun is close to the central FOV. Most of the participants did not perceive the colours of outdoor environment as natural when seen through EC glazed window. The majority of participants also desired to change the glazing configuration by adding an additional shading device.

Highlights

The highly variable nature of daylight often leads to either too little or too much light which can cause visual discomfort
We evaluated the acceptance of the glazing configuration, color perception of the view out and the elements inside the room created by such visual transmittance of the glazing
In scene 0.6C, 53% of the participants reported discomfort due to glare which was the lowest tv achieved by the tested EC glazing, indicating the need of lowering the transmittance further in cases when the sun is close to the viewing direction

Summary

Introduction

The highly variable nature of daylight often leads to either too little or too much light which can cause visual discomfort. EC glazing with its variable visual transmittance (tv) technology offers control over the visual and thermal environment [1] and can help mitigate the discomfort glare from daylight while maintaining a clear view to the outside [2]. There are very few studies on visual quality aspects such as color perception and view out through EC glazing [8]. This study evaluates various perceived visual comfort aspects of the application of EC glazing in a facade including discomfort glare, view out, color perception of the elements inside and outside the room. We evaluated the acceptance of the glazing configuration, color perception of the view out and the elements inside the room created by such visual transmittance of the glazing

Experimental design and set-up

Results and discussion

Conclusions