Development of experimental methods for quantifying the human response to chromatic glazing

Abstract

Thermochromic (TC) windows have the ability to regulate daylight and control the solar heat gains that shape a building's internal environment. They therfore offer the potential to improve indoor comfort and reduce building energy demand when used in place of traditional clear glazing systems. However, the quality of the luminous environment is affected due to their chromatic appearance (e.g. common TC coatings impart a bronze or blue hue), resulting in changes to correlated colour temperatures (CCT). Previous studies show that experiments performed under daylight conditions are difficult to be control, while those conducted under artificial lighting conditions cannot faithfully reproduce window properties. In order to investigate the influence of TC windows on visual performance and comfort of subjects in an efficient and economical way, an innovative test room cubicle was designed. It is a mock-up office lit by an artificial window, simulating luminous conditions filtered through two types of TC window (one blue tinted and one bronze tinted). Clear glazing was used as a reference.Objective visual tasks involving Landolt charts and subjective assessments made using questionnaires were used to determine subjects' response to the three different luminous conditions. Results show that the experimental method is effective at determining human response to chromatic glazing. Additionally, the method is flexible due to its small scale and its ability to artificially represent different window types.

Developing an Innovative Method for Visual Perception Evaluation in a Physical-Based Virtual Environment

“…An experiment under controlled artificial lighting conditions was considered appropriate for this study; as opposed to relying on daylight from real windows, whereby several uncontrollable parameters (i.e., spectral properties of the source, light intensity, etc.) would continuously change over time [21,23,24]. Also, other extraneous variables (e.g., noise, temperature, and humidity) could be carefully controlled.…”

“…and black was used. The colour represent the three main components of the RGB colour model [20,21]. The same size and position of the previous task were used and the words were again randomly allocated.…”

“…Only subjects who did not have epilepsy or suffer from migraines, motion sickness, and dizziness or sleep disorders were permitted to participate. An explanation of the tasks was given to the subjects, using samples with different versions of the tasks used in the experiment, before starting the experiment counterbalancing errors that could occur by unfamiliarity with the test [21]. Each session lasted approximately 40 minutes.…”

“…However, the comparisons that were performed did not consider a direct evaluation of the same conditions (e.g., bright real versus bright virtual) between real and virtual conditions, nor did the authors state the exact luminous conditions in both environments (i.e. luminances or illuminances), which highly affects task performance [20][21][22]. The same limitations were found in a study on lighting preferences for task performance [12].…”

Effect of Roller Shades on Chromaticity and Colour Rendering Performance of Transmitted Daylight

“…Vossen et al [33] studied the impact of a red luminescent solar concentrator on visual comfort and impression and found a generally increasing positive evaluation with increasing interior CCT, with the most positive evaluations above 7000 K. However, they defined a comfort boundary at 3283 K. They also determined an experimental comfort boundary at 39 for the CRI, which is much lower than the accepted standard value of good CRI for performance tasks in most types of workrooms (CRI 80). After studying a bronze (CCT = 4000 K), a clear (CCT = 5000 K), and a blue (CCT = 7000 K) window condition, Liang et al [34] concluded that subjects preferred to stay and work in the bronze window condition since it provides a warm tint and relatively natural rendering of the illuminated environment. Chinazzo et al [35] also investigated the impact of orange, neutral and blue glass on visual perception, focusing on the colour of light and visual judgement of the environment.…”