Visual comfort

Disability glare, visual impairment due to extreme brightness or contrast, can be caused by intense reflections from new constructions nearby existing transportation or building infrastructure. A case study analysis is performed of a disability glare hazard at an airport created by the installation of a large array of photovoltaic panels between an air traffic control tower and the aircraft taxiway. The panels reflect blinding quantities of daylight into the control tower, produce temporary after images and dangerously obscure taxiing aircraft. The existing FAA guidelines for installation of solar technologies are discussed relative to their shortcomings in identifying the glare hazard.
High dynamic range photography is used to analyze the glaring situation at the airport, and the authors propose a maximum brightness threshold of 30,000 cd/m2 based on the physiology of human vision and the brightness of tasks necessary for air traffic controllers at the case-study airport. Detailed reflectivity and three-dimensional models of the photovoltaic panels and the airport are created and validated against measured data. Using these models, an annual analysis is performed of the glare hazard. This analysis is displayed temporally using graphs and spatially using images that indicate where the glaring reflections originate. Such information is useful in identifying potential for disability glare before new constructions are built. Finally, the authors use the new method to analyze designs for remediation of the glare hazard.

This paper involves analyzing the issues and key considerations behind designing with
daylight in Denmark’s residential buildings from the early stages of design. The purpose of
this investigation is to understand the barriers and recommend ways to tackle them to
achieve visual comfort and energy efficiency. This has been acquired through analyzed
theory based research, as well as qualitative data acquired through interviews. The author
recommends that companies improve more towards implementing the knowledge and
philosophy of working with daylight as an early parameter in architecture. Moreover, closer
cooperation with legislators and proper understanding and use of feasible daylighting
technologies are keys to creating a uniform mind-set in the architectural practice of Denmark
in regards to proper daylight planning for residential buildings and achieving good results.

Discomfort glare is an underutilized parameter in contemporary architectural design due to uncertainties about the meaning of existing metrics, how they should be applied and what the benefits of such analysis are. Glare is position and view direction-dependent within a space, rendering it difficult to assess compared to conventional illuminance-based metrics. This paper compares simulation results for five glare metrics under 144 clear sky conditions in three spaces in order to investigate the ability of these metrics to predict the occurrence of discomfort glare and to hence support the design of comfortable spaces. The metrics analyzed are Daylight Glare Index, CIE Glare Index, Visual Comfort Probability, Unified Glare Rating, and Daylight Glare Probability. It is found that Daylight Glare Probability yields the most plausible results. In an attempt to deal with multiple positions and view directions simultaneously, the concept of an ‘adaptive zone’ is introduced within which building occupants may freely adjust their position and view in order to minimize the effect of glare. The spatial and directional extents of the adaptive zone depend on furniture layout and the freedom of occupants’ tasks. It is found that applying the adaptive zone concept to a sidelit office with manually operated venetian blinds reduces the predicted hours of intolerable discomfort glare from 735 to 18 occupied hours per year and increases the annual mean daylight availability from 40 to 72 percent.

"The writer discusses the concept of kitsch. Having reviewed a variety of approaches to kitsch, he posits an historical conception of it, connecting it to modernity and defining it as a coping-mechanism for modernity. He thus suggests that kitsch is best understood as a tool in the struggle against the particular stresses of the modern world and that it uses materials at hand, fashioning from them some sort of stability largely through projecting images of nature, stasis, and continuity. He discusses the relation of kitsch to fine art, arguing that fine art also has as its primary function a counter-movement to modernity. He suggests that the main difference between fine art and kitsch is that fine art, as well as its emotional function, also involves a reception context that allows it to assume an intellectual task. Among the writer's conclusions, he finds that positing a stark or absolute contrast between kitsch and fine art is unjustifiable as both have the same roots and objectives." [WilsonWeb].

What is kitsch? The varieties of phenomena which can fall under the name are bewildering. Here, I focus on what has been called “traditional kitsch,” and argue that it often turns on the emotional effect specifically captured by Edmund Burke’s concept of “beauty” from his 1757 'A Philosophical Enquiry into the Sublime and Beautiful.' Burkean beauty also serves to distinguish “traditional kitsch” from other phenomena also often called “kitsch”—namely, entertainment. Although I argue that Burkean beauty in domestic decoration allows for us to see “traditional kitsch” as resting on natural and even healthy impulses, I also argue that an all-too-common political function of traditional kitsch directs it to dangerous ends.

The combined effects of color temperature and illuminance in a small office on visual response and mood under various lighting conditions were examined in this study. Visual annoyance tests were conducted using a sample of 20 subjects in a full-scale mock-up test space. Computer and paper-based reading tasks were conducted for 500 lx and 750 lx illuminance levels under 3,000 K, 4,000 K and 6,500 K conditions. Two hypotheses were considered for the test in this study. The primary hypothesis was that visual perception is affected by the color temperatures of light sources. The secondary hypothesis was that better moods, such as relaxed and cozy feelings, are associated with low color temperatures given equal illuminance levels. The visual environment under the 3,000 K condition was characterized by glare and brightness, resulting in visual discomfort when target illuminance was higher than 500 lx. Occupants preferred 500 lx under the 6,500 K condition, and 500 lx and 750 lx under the 4,000 K condition, reporting better visual satisfaction when performing office tasks. Prediction models for visual comfort suggest that the less that subjects are visually bothered by light during tasks, the more visual comfort they feel. User satisfaction with light source color is critical for the prediction of visual comfort under different lighting conditions. Visual comfort was the most influential factor on mood. Lower color temperature was associated with better mood at lower illuminance levels, while higher color temperature was preferred at higher illuminance levels.

There are several physical parameters that are taken into consideration when determining the level of agreeability of an enclosed space. For instance, when choosing the louvers for a room there are a multitude of criteria that might be considered such as colour, material or the degree of opacity. However, these apparently small fixtures may have a significant impact also on other apparently unimportant factors like the sound pressure level and the reverberation time. This paper aims to present different types of devices used to control the way daylight enters a room, from both the illuminance level and the acoustical point of view. During the experimental campaign, five of the most common types of louvers were examined regarding their main role of blocking the light and moreover their influence on the reverberation time and sound pressure level in the analysed chamber.

We present a method for predicting visual comfort conditions of occupants in daylit spaces. Using an online survey, 67 occupants of a multi-story open plan studio space evaluated long-term visual comfort at their workstations in a substantially daylit space which is known to have glare problems. Visual comfort simulations of each occupant's specific location were conducted and compared to the survey results. Simulations included discomfort glare, monitor contrast, visibility of the sun in the field of view and the presence of direct light on the workplane. It was found that combining all four modes of discomfort analysis allows close agreement with occupant assessments ranging from 69% of morning assessments up to 87% of afternoon assessments. In contrast, following current practice by only considering a single source of discomfort, leads to under-predicting the glare problem. Only 29 to 47 percent of significant visual comfort assessments in this study were caused by a solitary type of discomfort. These findings show that visual discomfort is often caused by multiple independent effects, which must be evaluated simultaneously for a reliable visual comfort analysis.

Retro-reflective coatings applied to blinds of reduced geometric complexity promise to provide view to the outside while effectively controlling solar gains and glare. To characterize the reflection characteristics of such coatings over the entire solar spectrum, a novel extension to a scanning gonio-photometer is developed. The extended instrument is tested and applied to measure a coating's Bidirectional Reflection Distribution Function including the region of the retro-reflected peak. The measured data-sets are compiled into a data-driven reflection model for the daylight simulation software Radiance. This model is applied to illustrate the coating's effect in a comparison to purely diffuse and specular surface finishes on geometrically identical, flat blinds. Daylight supply, the probability of glare, and solar gains are assessed for an exemplary, South-oriented office under sunny sky conditions. The results indicate the potential of the coating to effectively shade direct sun-light even if applied on blinds with minimalistic geometries. The modeling technique is shown to be a general means to replicate the irregular optical properties of the coating, which cannot be represented by the standard models in daylight simulation software.

This paper presents various aspects which characterise traditional architecture in northern Greece, and
which can be related to bioclimatic and environmentally-friendly architecture. The study is based on the
documentation and the analysis of the architectural and bioclimatic aspects of remaining houses of the 19th
and the beginning of the 20th century. The aim of the study is to document and assess, both qualitatively
and quantitatively, all the afore-mentioned aspects in order to draw conclusions concerning the principles
which characterised this architecture and can be integrated to the restoration of existing buildings or the
design of new ones in traditional surroundings. The study focuses on towns and villages of Northern Greece
in an attempt to detect, document and analyse the bioclimatic elements and the design principles of
traditional architecture of the 19th and 20th century. The analysis is mainly based on a large-scale in-situ
research, which included the documentation of more than one hundred traditional buildings. From this
research, data concerning the typology, the form, the materials and the construction techniques of the
buildings are presented. Furthermore, the bioclimatic behaviour of typical constructions based on issues of
properties of the building shell, as well as thermal and visual comfort conditions throughout the year, are
presented. The results provide valuable information concerning the sustainability aspects of architectural
cultural heritage and lead to the understanding and formulation of a series of design and construction
principles that characterise the traditional architecture of Northern Greece and can be applied as guidelines
for the protection and conservation of historical buildings.

This study investigates how pedestrian experienced the lighting condition in transition area of Gamla Stan Tunnelbana Station. Transitional space in public station considered an important area because it could influence sense of safety, therefore encourage people to use public transport. In transitional space, human vision adapts to different lighting condition. This often became a main issue. Interior area in the stations are usually standardized, provides brightly lit environment according the regulation of the city. Meanwhile, the outdoor surrounding environment is often not supported by such standard. Consequently, the lighting condition between the indoor part of the station and the outdoor is became unbalance, creates a high contrast on the light level. This condition affect how the user experienced transitional spaces, and it might cause visual discomfort, disorientation. This study examined how pedestrian experienced the space using two methods, visual adaptation test and questionnaire.

Lapangan Futsal Pelle di Babarsari, Yogyakarta memiliki masalah pencahayaan pada siang hari, dimana cahaya matahari masuk ke lapangan dan mengakibatkan ketidaknyamanan visual bagi penggunanya. Penelitian ini coba memecahkan masalah tersebut dengan menggunakan shading.

Climate-based daylight simulation allows performance predictions for façade designs based on available climate data. Simulations based on daylight contribution coefficients coupled with models of sky luminance distribution make this tool available even in the design process. Metrics describing glare probability and the potential to substitute electrical lighting by daylight are applied and design proposals iteratively improved. The method is demonstrated on an existing building, the " Neubad Lucerne " , which is subject to design studies by students of architecture. Proposals to extend the two South-facing facades are developed, aiming at lower glare probability and optimized use of daylight to minimize electrical energy consumption for lighting. This paper shows: a) The different façade designs in photorealistic renderings. b) The quantitative analysis of useful daylight illuminance and daylight glare probability. c) A comparison of the designs according to the predicted daylight glare probability. Finally, It closes wih a comment on using climate-based simulation as a design tool.

Complex fenestration systems typically comprise co-planar, clear and scattering layers. As there are many ways to combine layers in fenestration systems, a common approach in building simulation is to store optical properties separate for each layer. System properties are then computed employing a fast matrix formalism, often based on a directional basis devised by JHKlems comprising 145 incident and 145 outgoing directions. While this low directional resolution is found sufficient to predict illuminance and solar gains, it is too coarse to replicate the effects of directionality in the generation of imagery. For increased accuracy, a modification of the matrix formalism is proposed. The tensor-tree format of RADIANCE, employing an algorithm subdividing the hemisphere at variable resolutions, replaces the directional basis. The utilization of the tensor-tree with interfaces to simulation software allows sharing and re-use of data. The light scattering properties of two exemplary fenestration systems as computed employing the matrix formalism at variable resolution show good accordance with the results of ray-tracing. Computation times are reduced to 0.4% to 2.5% compared to ray-tracing through co-planar layers. Imagery computed employing the method illustrates the effect of directional resolution. The method is supposed to foster research in the field of daylighting, as well as applications in planning and design.

This paper demonstrates a design process, in which intuition and building performance simulation are integrated to guide and inform the decisions in the conceptual and developmental phases. The main sustainable strategy has been identified as daylight harvesting for the refurbishment of an artificially lit pavilion into a library. "Light as an image of nature” is a concept that refers to the patches of the sunlight penetrating thru the branches and leaves of trees. This concept is used as the deriving concept in design, where perceptional qualities of space and light are orchestrated with optimal visual performance and visual comfort. Quantitative criteria (illuminance values, daylight factor, daylight autonomy, luminance distributions, and glare analysis) and visual appraisal are used for design evaluation. The resulting design process is iterative, where simulation is used extensively to provide feedback for accelerating and improving the design decisions.

In order to improve thermal comfort and visual comfort in the indoor environment of offices in IST-Taguspark campus, a PDLC type intelligent film, and a reflexive film with solar protection were implemented in two offices room in 37.76% of the glazed area.
Thermal comfort was analyzed using indoor temperatures and relative humidity monitoring, as well as external temperature and irradiance for two conditions: the first one for opaque PDLC and reflexive film, and in the second for the transparent PDLC. The variables were compared with those obtained in a reference office room without films.
To analyze its impact on visual comfort, two zones were created, one next to the window (ZJ) and another in the work zone (ZT), where the illuminance values were obtained in the reference office room, in the office with PDLC opaque and transparent and in the office with reflexive film in the presence of direct and diffuse radiation for specific time.
It was found that, comparatively to the reference office, PDLC and reflexive film are able to slightly reduce the internal temperature, as well as the cooling needs. Due to its radiation control, PDLC induces an improvement in the visual comfort when in the presence of direct radiation. Further, although in the presence of diffuse radiation the reference presents an average illuminance value slightly above 500 lx, the PDLC allows values to obtain similar values, while reflexive film does not show such significant improvements in the illuminance obtained values.

This study examines the influence of color temperature and illuminance levels on occupants" visual perception in a small office space. Field measurements and surveys were conducted in a full-scale mock-up space where four lighting conditions were formed by direct/indirect lighting fixtures. Results imply that the perception of glare increased as color temperature of light increased. Under equal color temperature conditions, the increase of illuminance caused more glare. The glare perception for paper tasks was weaker than that of computer tasks. Subjects felt that space became more spacious as color temperature increased under equal illuminance levels. In order to enhance visual comfort under 3500K conditions, the space should be kept bright and lighting environment needs to be maintained in a way that occupants see letters clearly. Under 5000K conditions, the perception of visually warm and brightness is an influential factor on visual comfort.

Drawing from ethnographic research in Canadian off-grid homes, this paper examines the notion of visual comfort. Like other types of comfort, visual comfort is an affective sensibility whose intensity and achievement are highly variable. Through their unique historical trajectories grid-connected homes have achieved and normalized visual comfort in particular ways, but—as the experiences of off-grid homes show—in no way is domestic visual comfort achievable only by flicking on an electric lightbulb powered by distant sociotechnical assemblages. Comfort is, in fact, not a uniform experience and off-gridders’ practices show vividly what it means to achieve it differently—in variable intensities and through alternative entanglements of nature and culture. In particular, we argue that off-gridders’ comfort is a direct reflection of their involvement in its production, ensuing from their participation in electricity generation

Overheating, high cooling energy demand and glare are recurrent problems in office buildings in Santiago and Valparaiso, Chile. Santiago (33°S) presents a Mediterranean climate, with a high temperature oscillation between day and night during cooling period. Valparaiso (33°S), by the coast, shows lower temperature fluctuation compared with Santiago. In order to evaluate impact on thermal and lighting performance of office buildings of these cities, a sensitivity study has been made. Variations on window facade area, type of glazing, orientation, solar protection and nocturnal ventilation and respective impact on cooling energy demand and lighting performance has been considered. The methodology includes an evaluation of heating and cooling demand and variation of indoor temperature when no conditioning system is applied. For this purpose a simulation software under dynamic conditions was used (TAS). The effect on natural lighting was also analysed using Radiance software. Daylight F...

The irregular reflection and transmission properties of innovative fenestration allow to redirect selectively admit or block solar irradiation based on its incident direction. Compared to systems that implement adaptivity by mechanical transformations, such tailored light scattering reduces the complexity of installation, operation and maintenance as well as the impact on outward view and the aesthetical appearance of buildings. Examples of such fenestration techniques, e.g. light redirecting films and Venetian blinds featuring irregular reflection properties, are presented with their gonio-photometrically measured scattering properties. Techniques to model optically complex fenestration to support product development and planning are presented. Effects on daylight availability, glare and solar gains are demonstrated. Preliminary results indicate the potential to control and modulate rather than to block irradiation the design of buildings aiming at high comfort and energy efficiency.

Refurbished heritage buildings usually lack in meeting the required standards defined for the new function especially when reused as educational buildings. Therefore, they are usually equipped with different post-occupancy retrofit strategies to achieve an acceptable level of environmental quality and energy demand. Daylight quality and the distribution of natural light is a critical issue in educational spaces, given that the low level of illuminance in classrooms can decrease students' performance and disrupt visual tasks. In this study, daylight performance of below-grade south-facing classrooms in a heritage building in Tehran, Iran is investigated by implementing 57 different daylighting retrofit strategies using climate-based daylight simulations, in relation to the metric Useful Daylight Illuminance 300-3000lux (UDI-Autonomous). The research proposes the use of reflectors on the interior ceiling and exterior side of the windows (on the ground) to achieve the highest resul...