A Critical Investigation of Common Lighting Design Metrics for Predicting Human Visual Comfort in Offices with Daylight

Abstract:Energy-efficient building performance requires sophisticated control systems that are based on realistic occupant behaviour models. To provide robust data for the development of these models, research studies in real-world settings are needed. Yet, such studies are challenging and necessitate careful design in terms of data collection methods and procedures. This paper describes and critiques the design of a mixed methods approach for occupant behaviour research. It reviews the methodology developed for a longitudinal study in a real-world office environment where occupants' experience with a novel facade technology (electrochromic glazing) was investigated. The methodology integrates objective physical measurements, observational data and self-reported experience data. Using data from one day of the study, this paper illustrates how the different sources can be combined in order to derive an in-depth understanding of the interplay between external daylight conditions, characteristics of the facade technology, occupant interaction with the technology and the resulting occupant experience. It was found that whilst the individual methods may be affected by practical limitations, these can be partially offset by combining physical measurements and observations with self-reported data. The paper critically evaluates the individual techniques, as well as the benefits of their integration and makes recommendations for the design of future occupant behaviour studies in real-world settings.

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“…Work is in progress to identify parameters that may be more informative and more strongly linked to occupant perception [8].…”

Section: Further Work In Regards To Ec Glazing Researchmentioning

confidence: 99%

Evaluation of a Mixed Method Approach for Studying User Interaction with Novel Building Control Technology

et al. 2016

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“…According to Wienold [2009] and Reinhart and Wienold [2011], a DGP value of less than 0.35 is considered "imperceptible"; therefore, no discomfort glare should be expected from the tested configurations. Nonetheless, care should be taken because DGP, in its current definition, is apparently not robust enough to be used as a standalone daylighting visual comfort design guide, because it may underestimate glare sensation in some cases [Van Den Wymelenberg and Inanici 2014]. Figure 10 displays false color maps of horizontal illuminance values on the workplane under all configurations.…”

Section: Comparison Of Various Configurationsmentioning

confidence: 99%

Analysis of Various Opening Configurations of a Second-Generation Virtual Natural Lighting Solutions Prototype

Mangkuto

Aries

Loenen

et al. 2014

LEUKOS

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To address the absence of natural light in working spaces, virtual natural lighting solutions (VNLS) can be promising. VNLS are systems that artificially provide lighting as well as a realistic outside view with properties comparable to those of real windows and skylights. This article discusses the evaluation and analysis of various opening configurations of a second-generation VNLS prototype, which features an array of light emitting diode (LED) tiles coupled with a line of linear LED fixtures with adjustable color temperatures that provide direct light. Simulation using Radiance was performed and validated with the measurement results. Various possibilities of placing the prototypes inside the test room were investigated in Radiance to determine the effect on space availability and visual comfort. Based on the comparison of seven configurations of two prototypes with equal total opening size, it was found that nearly all configurations tested yielded a space availability of 100% with a criterion of 200 lx and where space availability is defined as the percentage of points on a horizontal grid that meet or exceed the target illuminance. Taking 300 lx as the criterion, two openings on each short wall facing each other (configuration 2) and four openings on a long wall (configuration 5) yielded space availabilities of more than 90%. Taking 500 lx as the criterion, configurations 2 and 5 yielded space availabilities between 25% and 50%. The highest uniformity (E min /E avg ) was achieved under configuration 2 (0.59), whereas the maximum daylight glare probability (DGP) values under all configurations were between 0.25 and 0.30. Our simulation results suggest that the space availability in a private office can be optimized by placing a VNLS prototype on each short wall facing each other or by placing two on a long wall.

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“…In recent years user assessment studies on daylight-induced visual discomfort for application mainly in office buildings have been conducted more extensively [1][2][3][4][5]. These studies are proposing different metrics to predict discomfort caused by the luminance distribution in the field of view.…”

Section: Introduction and Objectivesmentioning

confidence: 99%

“…For instance, K. Van Den Wymelenberg et al [5,6] concluded, that the overall performance of existing glare metrics is rather poor. They based their conclusions on a Pearson correlation between ordinal subjective response and the metric values.…”

Section: Introduction and Objectivesmentioning

confidence: 99%

Comparison of Luminance Based Metrics in Different Lighting Conditions

Wienold

Andersen

Khanie

et al. 2018

Proceedings of the Conference at the Cie Midterm Meeting 2017 23 – 25 October 2017, Jeju, Republic of Korea

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In this study, we evaluate established and newly developed metrics for predicting glare using data from three different research studies. The evaluation covers two different targets: 1. How well the user's perception of glare magnitude correlates to the prediction of the glare metrics? 2. How well do the glare metrics describe the subjects' disturbance by glare? We applied Spearman correlations, logistic regressions and an accuracy evaluation, based on an ROCanalysis. The results show that five of the twelve investigated metrics are failing at least one of the statistical tests. The other seven metrics CGI, modified DGI, DGP, Ev, average Luminance of the image L avg , UGP and UGR are passing all statistical tests. DGP, CGI, DGI_mod and UGP have largest AUC and might be slightly more robust. The accuracy of the predictions of afore mentioned seven metrics for the disturbance by glare lies in the range of 75-83% and does not confirm findings from other studies stating a poor performance of existing glare metrics.

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A Critical Investigation of Common Lighting Design Metrics for Predicting Human Visual Comfort in Offices with Daylight

Cited by 150 publications

References 22 publications

Evaluation of a Mixed Method Approach for Studying User Interaction with Novel Building Control Technology

Evaluation of a Mixed Method Approach for Studying User Interaction with Novel Building Control Technology

Analysis of Various Opening Configurations of a Second-Generation Virtual Natural Lighting Solutions Prototype

Comparison of Luminance Based Metrics in Different Lighting Conditions

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