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Recently, there have been multiple proposals for faster methods to calculate glare metrics, daylight glare probability (DGP) in particular. This is driven simultaneously by the lengthy times required to simulate DGP with a conventional image-based approach and accumulating evidence from subjective glare evaluation experiments showing that accounting for both the saturation and contrast in a view improves the accuracy of a glare prediction. While some of these methods have been presented with their own validations, comparisons of accuracy across methods are limited by the differences in tested scenarios and resulting distributions of daylight conditions. This study compares six point-based methods and two zonal estimations for quickly calculating hourly DGP values from three viewpoints with different relationships to the window across a range of scenarios. These include scenarios with direct and semi-specular transmission and others with specular and semi-specular reflection. We find that while some of these fast methods closely align with results from a reference simulation, others introduce large and consequential errors.

A recent study on the glare protection performance of electrochromic (EC) glazing showed that visible transmittance levels lower than 0.6% are necessary to achieve comfortable situations for sun positions, that were close to the central field of view. However, the question that arises is how often such situations occur throughout the year and how the glare protection performance of EC systems is for typical office situations for different climates and orientations. This study aims to quantify the annual performance for such configurations by applying improved simulation methods to conduct annual glare simulations and comparing them to the EN17037 classifications. The enhancement of the simulation method compared to existing methods was necessary to correctly consider the blurring effect in the lens of the eye – neglecting this would lead to an overestimation of glare. We found that for mid and north European climates the extreme situations do not occur such often, so that the ECglazing systems being able to switch to transmittance levels of 1% can mitigate glare throughout the year reasonably well for typical office situations and reaches typically the highest glare protection category according to EN17037 for a viewing direction, that is parallel to the facade. For more sunny climates such as Rome, slightly lower transmittance levels (around 0.5%) would be necessary to achieve a similar glare protection level. The study also revealed that tables E.7 and E.8 of EN17037 with pre-calculated 95-percentile Daylight Glare Probability (DGP) values should be re-calculated.

The ipRGCs in the human eye mediate several effects on people, such as alertness and circadian rhythms. The spectral, temporal and spatial characteristics of light influence the magnitude of these effects. To facilitate the anticipation of the ipRGC-influenced light (IIL) responses in building design, new simulation tools are needed. This paper presents an extension to the open-access simulation tool Lark, available as a plugin to Grasshopper for Rhino. The proposed extension includes a set of additional options, components, and templates that incorporate currently available knowledge on the IIL responses. The applicability of the extension is demonstrated in a simulation workflow.

At the conceptual-stage, building performance simulation (BPS) based evaluations are being increasingly used for tasks such as ranking of competing massing design proposals. However, such conceptual stage evaluations suffer from information deficiency in building level design attributes. The resulting uncertainty in performance evaluations raises questions regarding their usefulness for decision-making. We used a risk-based decision evaluation metric called expected opportunity loss to assess the reliability of a BPS-based ranking of conceptual stage massing schemes. We found daylighting assessments (spatial Daylight Autonomy) to be least reliable, with 22% chance of making an incorrect decision at the conceptual stage, followed by annual heating (15%) and cooling demand (8%). This work provides a structured framework for evaluating utility of conceptual stage BPS models and a purposeful basis for integration of BPS assessments in the design process, subject to level of design development. [ABSTRACT FROM AUTHOR]

With the growing awareness about ipRGC-influenced light (IIL) responses, design applications related to these responses are flourishing. To compare design options and optimize lighting conditions for building occupants, lighting simulations are typically used. However, as our IIL responses depend on the spectral characteristics of light, spectral simulations are required. The goal of this study is to validate two spectral simulation tools, ALFA and Lark, for the study of indoor spaces in relation to occupants' IIL responses. Indicators associated with IIL responses derived from ALFA- and Lark-simulated data are compared against indicators derived from data measured under indoor daylighting and electric lighting conditions. The results show that Lark outperforms ALFA in most cases, with a simulation error in the ±20% range for point-in-time indicators. When accounting for time dynamics of light exposure, at least 9% of the daylight exposures simulated for a 6-h period in Lark lead to a significant error. [ABSTRACT FROM AUTHOR]

Existing daylight standards encourage larger glazed areas, which often results in larger solar gains in the summer and heat losses in the winter. To avoid these, shadings, thicker frames and multiple panes of glass are required to respect operational energy targets. These imperatives in turn influence the embodied carbon of the building. Yet the performance trade-offs between daylight and embodied carbon have so far largely remained overlooked in existing research. More specifically, there is currently no guidance on what reasonable carbon budget should be associated with façade and its components. The present study thus aims to 1) reveal how whole life carbon is affected by improving daylight and 2) define carbon budgets at the façade and its components level. In this paper, an explorative method is proposed and its potential to achieve the study's aims is illustrated through its application to a specific case study. Based on the analysis of 9000 design alternatives, increasing spatial daylight autonomy by 24 % in carbon-intensive facades made of concrete and brick can reduce the embodied carbon by 15 % and 10 % respectively. In contrast, the same daylight improvement in low-carbon façade alternatives made of timber would instead, increase whole life carbon by 65 % for the case study considered. The method also offers prospective insights: for the chosen case study, achieving a well daylit space will be increasingly challenging after 2040, due to a substantial reduction in the façade carbon budget by 2040, which is projected to be nearly half of what it is today. • The performance trade-offs between daylight and whole life carbon across 4 different construction techniques are assessed. • Increasing daylight autonomy in concrete and brick facades is in favor of whole life carbon emissions. • Enhancing daylight in low-carbon facades, e.g. wood framed and cellulose fiber, increases whole life carbon by 65 %. • Creating well-daylit spaces compliant with carbon budget becomes increasingly challenging as of 2040. [ABSTRACT FROM AUTHOR]

Evaluation of solar heat gain and daylight distribution through complex window and shading systems requires the determination of the bi-directional transmission distribution function (BTDF). Measurement of BTDF can be time-consuming, and inaccuracies are likely because of physical constraints and experimental adjustments. A general calculation methodology, based on more easily measurable component properties, would be preferable and would allow much more flexibility. In this paper, measurements and calculations are compared for the specific case of prismatic daylight-redirecting panels. Measurements were performed in a photogoniometer equipped with a digital-imaging detection system. A virtual copy of the photogoniometer was then constructed with commercial ray-tracing software. For the first time, an attempt is made to validate detailed bi-directional properties for a complex system by comparing an extensive set of experimental BTDF data with ray-tracing calculations. The results generally agree under a range of input and output angles to a degree adequate for evaluation of glazing systems. An analysis is presented to show that the simultaneously measured diffuse and direct components of light transmitted by the panel are properly represented. Calculations were also performed using a more realistic model of the source and ideal model of the detector. Deviations from the photogoniometer model were small and the results were similar in form. Despite the lack of an absolute measurement standard, the good agreement in results promotes confidence in both the photogoniometer and in the calculation method.

Window views that provide visual connections to the outdoors have been shown to have multiple positive effects on occupants (Heschong [25]). Definition Design teams regularly analyze building performance, including energy and indoor environmental quality to support the building design, starting with conceptual design and continuing throughout the complete design process. In contrast, at later design stages, it is possible to consider more specific variables regarding facade materials, building program, and occupant characteristics using complex metrics such as spatial and temporal analyses. The first approach is binary (informing the design team "what to do, and what not to do"), while the second approach is a sensitivity issue to improve the building design, construction, retrofitting, maintenance, or operational change, and provide "better than just enough.". [Extracted from the article]

The size of window openings is widely acknowledged as an important factor in our spatial perception. However, little is known about how the perception and preference of windows changes between countries, leaving a gap of knowledge regarding the applicability of research findings across latitudes. This article presents the outcomes of a study investigating regional differences in the perception of spaces with varying window size (small, medium, and large), space size (small and large), spatial context (working and social), and sky type (overcast and two types of clear sky). As the regional differences were the main studied factor, the study was performed in Norway, Switzerland, and Greece, representing northern, central, and southern European latitudes, respectively, and used virtual reality as a means to replicate the same experiment in different locations. In total, 406 participants evaluated eight spatial attributes using an 11-point Likert-type scale. Results indicated that regional differences could be observed in the participants' responses, with significant differences in how pleasant and calm the space was perceived, found not only between participants in Greece and Norway in all the studied window sizes, but also between Greece and Switzerland for the medium and large windows, indicating that even small variations in latitude within Europe can affect the spatial perception. The findings of this study reveal that spaces with specific fenestration characteristics might not induce the same response across different latitudes in Europe, and thus, have important implications for daylighting and architectural design, which would motivate the use of region-specific parameters. [ABSTRACT FROM AUTHOR]

Building Performance Simulation (BPS), a useful tool to assess the operational performance of buildings and systems, can often be computationally expensive. The use of BPS is cumbersome for problems where the speed of response is important, e.g. real-time control, uncertainty quantification, parametric exploration, or stock modelling. Emulators, such as those based on regression, offer a faster substitute, but their reliability can be questionable. This paper proposes seven tests to check if an emulator is a suitable replacement for simulation in practice. The tests are categorized using four criteria: accuracy, speed, generalisability, and ease of use. The tests can be included in the process of setting up an emulator-based workflow. A use case is provided for emulators based on linear and non-linear regression (Gaussian Process models). This work aims to enable a practitioner to reliably conduct performance assessment for buildings using emulators. [ABSTRACT FROM AUTHOR]

Reconstruction algorithms are at the forefront of accessible and compact data collection. In this paper, we present a novel reconstruction algorithm, SpecRA, that adapts based on the relative rarity of a signal compared to previous observations. We leverage a data-driven approach to learn optimal encoder-array sensitivities for a novel filter-array spectrometer. By taking advantage of the regularities mined from diverse online repositories, we are able to exploit low-dimensional patterns for improved spectral reconstruction from as few as p = 2 channels. Furthermore, the performance of SpecRA is largely independent of signal complexity. Our results illustrate the superiority of our method over conventional approaches and provide a framework towards "fourth paradigm" spectral sensing. We hope that this work can help reduce the size, weight and cost constraints of future spectrometers for specific spectral monitoring tasks in applied contexts such as in remote sensing, healthcare, and quality control. [ABSTRACT FROM AUTHOR]

Information is the resolution of uncertainty and manifests itself as patterns. Although complex, most observable phenomena are not random and instead are associated with deterministic, chaotic systems. The underlying patterns and symmetries expressed from these phenomena determine their information content and compressibility. While some patterns, such as the existence of Fourier modes, are easy to extract, advances in machine learning have enabled more comprehensive methods in feature extraction, most notably in their ability to elicit non-linear relationships. Herein we review methods concerned with the encoding and reconstruction of natural signals and how they might inform the discovery of useful transform bases. Additionally, we illustrate the efficacy of data-driven bases over generic ones in encoding information whilst discussing these developments in the context of "fourth paradigm" metrology. Toward this end, we propose that existing metrological standards and norms may need to be redefined within the context of a data-rich world. [ABSTRACT FROM AUTHOR]

Daylight provision to the indoor space is affected by different building elements that cannot be fully controlled by the users, such as the window size of a space. The dimensions of the fenestration not only affect the lighting levels, but they also affect how the space is perceived by its users. The present study examines three different window sizes via virtual reality, to study how they affect the perception of both a small and a large space at high latitudes. Additionally, two context scenarios (socializing and working), as well as three different sky types (overcast sky and clear skies with either high or low sun angle) were evaluated. The experimental study applied a mixed design with within-subjects and between-subjects factors. A total of 150 participants evaluated the scenes using a Likert-type scale to rate eight different subjective attributes. The statistical results showed that both window size and space type significantly affect the participants' spatial perception, as well as their satisfaction with the amount of outside view. Larger windows led to more positively evaluated spaces for all studied attributes. Moreover, a significant interaction was found between window size and type of space for the satisfaction with the amount of view in the space, indicating that the window size was dependent on the type of space in which the windows are located. Specifically, the window sizes were rated higher in the small space than in the large space for the evaluation of amount of view. The findings show that window size affects how people perceive a space, and additionally, that other spatial features, such as space type, affect window size preferences. [ABSTRACT FROM AUTHOR]

Objective: Temperature-color interaction effects on subjective perception and physiological responses are investigated using a novel hybrid experimental method combining thermal and visual stimuli from real and virtual reality (VR) environments, respectively.Background: Despite potential building design applications, studies combining temperature with daylight transmitted through colored glazing are limited due to hard-to-control light conditions. VR is identified as a promising experimental tool for such investigations that overcomes the limitations of experiments using daylight.Method: Fifty-seven people participated in an experiment combining three colored glazing (orange/blue/neutral) and two temperatures (24°C/29°C). Exposed to one color-temperature combination, participants evaluated their thermal, visual, and overall perception, whereas their physiological responses (heart rate, skin conductance, and skin temperature) were continuously measured.Results: Daylight color significantly affected thermal perception, whereas no significant effects of temperature on visual perception were found. Acceptability of the workspace was affected by both color and temperature. Cross-modal effects from either daylight color or temperature levels on physiological responses were not observed.Conclusion: In the VR setting, the orange daylight led to warmer thermal perception in (close-to-) comfortable temperatures, resulting in a color-induced thermal perception and indicating that orange glazing should be used with caution in a slightly warm environment.Application: Findings can be applied to the design of buildings using new glazing technologies with saturated colors, such as transparent photovoltaics. Despite some limitations, the hybrid environment is suggested as a promising experimental tool for future studies on indoor factor interactions. [ABSTRACT FROM AUTHOR]

This paper presents the combined effect of indoor temperature (19 °C, 22 °C, and 26 °C) and colored glazing (blue, orange, and neutral) on visual perception of daylight. Experiments were performed in an office-like test room, in which 75 participants were fully immersed under visual and thermal stimuli. Findings are discussed in terms of cross-modal effects of indoor temperature on visual perception, as well as of unimodal effects of glazing color on visual perception, investigated in terms of color of light and visual environment evaluations. Results show the presence of cross-modal effects of indoor temperature on visual perception of both the visual environment and the color of light. Indoor temperature affected the visual environment evaluation as, first, brightness comfort resulted higher at lower temperatures, and second, the light was associated to warmth adjectives more often at higher temperatures. On the other hand, indoor temperature influenced the color of light evaluation as, only at lower temperatures, daylight tinted by the blue glazing was considered less pleasant and less comfortable, and was chosen less often over the daylight tinted by the orange glazing. In terms of unimodal effect of colored glazing on visual perception, results indicate that the neutral glazing was always preferred over the two colored ones, probably due to the use of saturated colors. The orange glazing, however, was associated with the most relaxing and warmest daylight. These findings have important implications regarding the use of glazing with saturated colors in buildings and expand our understanding of temperature–color interaction – so far investigated only with electric light – to daylight evaluations. [ABSTRACT FROM AUTHOR]

Façade design is claimed to fulfil a number of requirements in workplaces, ranging from privacy to safety and from comfort to aesthetics. For future R&D efforts in façade design, identifying the key drivers that should shape contemporary facades in office buildings is not always an easy task because of the discrepancies that can emerge between the diverse expectations from professionals and the possible conflicts that can exist in conciliating global design trends with local climate constraints. This research aims to enrich the debate on façade design developments for office buildings, by discussing the outcomes of an on-line survey distributed worldwide among professionals working in the building design sector. Outcomes of 245 responses are summarized in an interactive chart that enables to visualize the potential of some main aspects and technologies characterizing today's office building skins. The potential is shown based on the observed level of relevance among different professional profiles or climates. While energy and comfort emerged as the aspects attaining global and interdisciplinary consensus, the features that entailed psychological or emotional reactions attracted the most diverse evaluations. Despite not being fully exhaustive, the observations arising from this study can help with identifying possible research and developments gaps in the field. [ABSTRACT FROM AUTHOR]

This article presents a novel experimental method that uses a virtual reality (VR) headset, aiming to provide an alternative environment for the conduction of subjective assessments of daylit spaces. This method can overcome the difficulty of controlling the variation of luminous conditions, one of the main challenges in experimental studies using daylight, and its novelty lies in the implementation of physically based renderings into an immersive virtual environment. The present work investigates the adequacy of the proposed method to evaluate five aspects of subjective perception of daylit spaces: the perceived pleasantness, interest, excitement, complexity, and satisfaction with the amount of view in the space. To this end, experiments with 29 participants were conducted to compare users' perceptions of a real daylit environment and its equivalent representation in VR and test the effect of the display method on the participants' perceptual evaluations, reported physical symptoms, and perceived presence in the virtual space. The results indicate a high level of perceptual accuracy, showing no significant differences between the real and virtual environments on the studied evaluations. In addition, there was a high level of perceived presence in the virtual environment and no significant effects on the participants' physical symptoms after the use of the VR headset. Following these findings, the presented experimental method in VR seems very promising for use as a surrogate to real environments in investigating the aforementioned five dimensions of perception in daylit spaces. [ABSTRACT FROM AUTHOR]

Abstract Voluntary green-rating systems exist in different forms worldwide to certify the sustainability of residential and commercial buildings and help national policies promote energy-efficient design practices. Despite the general assumption that sustainable buildings also provide high comfort and healthy conditions, existing studies on green-rated buildings led to controversial conclusions in this regard. This paper aims to report the results of a post-occupancy evaluation (POE) conducted on four Swiss green buildings certified with the Minergie label to analyse their ability in providing comfort to their occupants. The POE protocol included winter and summer environmental monitoring campaigns (long-term and instantaneous measurements) as well as extensive and point-in-time comfort surveys. From the study it was found that, although the observed environmental factors were most of the time complying with the norm prescriptions, the indoor conditions were never attaining the commonly used 80% satisfaction threshold by the users. Temperature and air quality appeared, in particular, as the most critical factors, with satisfaction rates never greater than 50% in three out of the four case studies. Design factors related to the personal control on the indoor environment as well as personal factors like gender, climate of origin and duration of residence in the country were also found to have an impact in the comfort rating. Professionals involved in the design and management of these buildings all agreed that feedback of this kind from building in use could help inform the design and operational process and move towards more effective green building certification systems and regulations. Highlights • A POE was conducted on four green-rated buildings in Switzerland. • The observed IEQ factors were found for the most in compliance with the norms. • A significant rate of building users dissatisfaction with IEQ was reported. • Personal environmental control and personal factors were found to influence comfort. • Possible inadequacy of comfort standards and of green design strategies is discussed. [ABSTRACT FROM AUTHOR]

The need for adequate instruments to support practitioners toward achieving sustainable and energy-efficient architectural and urban design has long been acknowledged. Motivated by identified shortcomings of building performance assessment tools for conceptual neighborhood-scale design, this paper proposes a novel workflow to enable practitioners to efficiently explore a space of design alternatives and compare them in terms of their energy and daylight performance. The workflow includes a multi-criteria optimization algorithm, which is coupled to a performance assessment engine based on predictive mathematical models. To get some insight on the potential added value for design and the usability of this approach in practice, the workflow has been implemented as a plug-in to an existing 3D modeling software and subsequently tested by practitioners during workshops, notably on real projects provided by the participants. Outcomes from the workshops, which include responses from the participants to a pre- and post-test survey, are presented. Results highlight the relevance of the proposed workflow for informing decisions about early-stage building massing on the basis of the considered performance criteria. Improvements envisioned for both the workflow and its implementation are highlighted and discussed. [ABSTRACT FROM AUTHOR]

Previous studies have shown that access to a satisfactory view to the outside with sufficient daylight is essential for building occupants' health and well-being. It has also been suggested that certain features of visual content improve view-out quality, such as horizontal stratification, natural landscapes, distant features, and diversity of visual elements. Additionally, having movement and changes in viewing content has been shown to further strengthen building occupants' engagement and connectivity to their surrounding environment. The objective of this paper is to review the literature on the dynamism of the view content and the inclusion of this criterion in the current metrics of view evaluation. Our review revealed a need for further research on view dynamism, especially focusing on testing different types, speeds, and scales of movement on view quality assessment. It also showed that more comprehensive view evaluation frameworks should be developed to accurately preserve the dynamic qualities of window views in experimental settings. While many view rating metrics have acknowledged the importance of movement, this criterion is to date ignored or only poorly included in existing metrics, which further highlights the need of learning more about this topic. [Display omitted] [ABSTRACT FROM AUTHOR]

Despite recent developments, neighborhood-scale performance assessment at the early-design phase is seldom carried out in practice, notably due to high computational complexity, time requirement, and perceived need for expert knowledge, ultimately limiting the integration of such a task into the design process. In this paper, we introduce a predictive modeling approach to rapidly obtain an estimate of the performance of early-design phase neighborhood projects, from simple geometry- and irradiation-based parameters. The performance criteria considered are the passive solar and daylight potential, respectively quantified by the energy need for space heating and cooling (given certain assumptions) and the spatial daylight autonomy at the ground-floor level. Two predictive models, or metamodels, are developed following distinct techniques: a multiple linear regression function and a Gaussian Processes regression model. These are developed from a reference dataset acquired through the parametric modeling and simulation of neighborhood design variants. When tested on designs provided by professionals, the metamodels with the highest accuracy within the compared types (MLR versus GPs) portray a prediction error below 10% in 87% (respectively 60%) of the cases for the passive solar (resp. daylight) potential. Results show this approach to be a promising alternative to running detailed simulations when comparing early-design variants. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach for the assessment of daylight performance in buildings, venturing beyond existing methods that evaluate 2-dimensional illumination and comfort within a fixed field-of-view, to predict human responses to light concerning non-visual effects, visual interest, and gaze behavior in a visually immersive scene. Using a 3D rendered indoor environment to exemplify this coordinated approach, the authors assess an architectural space across a range of view directions to predict non-visual health potential, perceptual visual interest, and gaze behavior at the eye level of an occupant. This method allows the authors to explore and demonstrate the impact of space, time, and sky condition on three novel daylight performance models developed to predict the effects of ocular light exposure using a human-centric approach. Results for each model will be presented in parallel and then compared to discuss the need for a multi-criteria assessment of daylight-driven human responses in architecture. A parallel and comparative approach can allow the designer to adapt the architectural space based on the program use and occupants needs. [ABSTRACT FROM AUTHOR]

While the influence of a glare source's spectrum on sensitivity to discomfort glare has been demonstrated repeatedly under electric light conditions, it has not yet been studied under actual daylit conditions. To investigate the influence of spectral alterations of the sun disc on glare perception when seen behind a colored glazing, we performed a cross-evaluation of occupants' visual comfort in a space either daylit through blue-tinted electrochromic (EC) glazing (20 participants) or through color-neutral glazing (55 participants), having selected two types of glazing that are widely employed in commercial buildings. Under both types of glazing, participants experienced four glare scenarios presenting different glazing transmittances (from low to extremely low) in which the sun was the only glare source visible. Comparing the participants' responses to glare, we found that participants experienced discomfort more often in blue-tinted glazing compared to color-neutral glazing, even though glare metrics would have predicted higher levels of discomfort in these latter cases. This indicates that participants basically tolerated glare better under color-neutral daylit conditions compared to blue-colored conditions. To explain our findings, we considered four spectral discomfort glare sensitivity functions that have previously been proposed to replace the standard CIE V 2° (λ) and applied them to the DGP and CGI glare metrics. However, none of these adjustments to glare metrics made any difference to our findings, which consistently showed an increased glare sensitivity under shorter wavelengths, indicating that its cause should be sought elsewhere. Some hypotheses are formulated at the end of the paper in this regard. • We evaluated the influence of color of a glare source on the discomfort glare perception under indoor daylight conditions. • Participants experienced glare from the sun behind either blue EC glazing or color-neutral glazing, of low transmittances. • Participants tolerated glare better under color-neutral glazing, as opposed to blue glazing. • None of the previous spectral discomfort glare models could accurately capture the increased discomfort in blue glazing. [ABSTRACT FROM AUTHOR]