Sustainable lighting design through the analysis of spatial and time non-uniformities in natural lighting with the metric of the information theory (original) (raw)
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The indoor visual comfort of subjects faced with indoor ambient lighting varies with the position of the subject and is not constant over time. Average performance indexes, such as the mean value of Daylight Factor and Daylight Autonomy, are commonly used to analyse lighting distribution. These indexes, however, don’t properly take into account either the spatial or the time distribution of values affecting the non-uniformity of environmental lighting. Indeed, these are limited to the definition of a mean value or to the assessment of time availability of daylighting. This paper examines spatial and temporal non-uniformities in indoor lighting as possible causes of discomfort for occupants. The goal is to propose and verify possible supplementary tools to integrate traditional methods of evaluating ambient indoor lighting. Use of the entropy theory with a probabilistic approach can help to obtain more detailed information about the environment. The authors have developed a case study of several sample environments and have analysed the relationships between lighting parameters and typical indices of information theory. Results show that this approach could be a useful way for predicting possible indoor visual comfort issues and for developing a preliminary assessment to a sustainable building design.
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International Journal of Structural and Civil Engineering Research
Considering the work requirements and the current way of life, human beings spend more and more hours a day indoors. Therefore, it is essential to make an appropriate optimization of windows in architecture, to reduce energy consumption and its impact on the environment, as well as an improvement in the health and wellness of the occupants by promoting a suitable circadian cycle. This study aims to simplify the calculation of daylighting in interior spaces, establishing a more precise link between one of the most common static metrics, the Daylight Factor (DF) and another of the main dynamic metrics, the Daylight Autonomy (DA), linking them through the Minimum Daylight Autonomy (DAm), allowing to obtain precise dynamic daylighting values without the need for a sophisticated and slow computational simulation. In this way, a work methodology is proposed and applied as a practical example in 6 European capital cities with different latitudes and sky types, quantifying the relationship between both metrics for each of them and analysing the current tendencies of the results. The work concludes with a first transposition of the results of the study samples, allowing its easy and fast application of this link to any professional of Architecture.
Energies
Work processes and sociological structures can differ significantly between organizations. These organizational aspects determine user behavior, which in turn exerts considerable influence on the key performance indicators of artificial lighting systems. Accordingly, the use of generalized assumptions about user behavior in the building design phase can lead to large discrepancies between design and operation. In the following work, the possible influences of different occupancy schemes, an essential aspect of user behavior and shaped by the organization, on energy demand and workplace-related daylight dose are evaluated. For this purpose, calculations are made based on real measurement data of an open-plan office with zoned lighting. Multi-level calculation models are used to determine improved user distributions in the room to ensure optimization according to the desired target criteria. The results show that occupancy schemes have a significant impact on energy demand, contributi...
Buildings, 2016
The interactions between building occupants and control systems have a high influence on energy consumption and on indoor environmental quality. In the perspective of a future of "nearly-zero" energy buildings, it is crucial to analyse the energy-related interactions deeply to predict realistic energy use during the design stage. Since the reaction to thermal, acoustic, or visual stimuli is not the same for every human being, monitoring the behaviour inside buildings is an essential step to assert differences in energy consumption related to different interactions. Reliable information concerning occupants' behaviours in a building could contribute to a better evaluation of building energy performances and design robustness, as well as supporting the development of occupants' education to energy awareness. The present literature survey enlarges our understanding of which environmental conditions influence occupants' manual controlling of the system in offices and by consequence the energy consumption. The purpose of this study was to investigate the possible drivers for light-switching to model occupant behaviour in office buildings. The probability of switching lighting systems on or off was related to the occupancy and differentiated for arrival, intermediate, and departure periods. The switching probability has been reported to be higher during the entering or the leaving time in relation to contextual variables. In the analysis of switch-on actions, users were often clustered between those who take daylight level into account and switch on lights only if necessary and people who totally disregard the natural lighting. This underlines the importance of how individuality is at the base of the definition of the different types of users.
Lighting conditions in sustainable buildings: results of a survey of users' perceptions
Architectural Science Association, 2010
For the last four years the authors have been investigating the performance in practice of a range of sustainable commercial and institutional buildings worldwide. These investigations involved the principal author in one or more visits to each of the buildings and the personal distribution and collection of a questionnaire survey seeking the users' perceptions (on a seven-point scale) of a range of factors: operational, environmental, personal control, and satisfaction. For this paper the authors focus on the users' perceptions of the quality of lighting in their work areas. The users' overall perceptions of lighting conditions are presented and analyzed, first with an overview of the average scores for each question, followed by a look at the shapes of their distributions over the set of buildings, and then the results of some correlations between Lighting Overall and a number of other key performance factors such as Health, Productivity and OverallComfort. It was found that Lighting Overall was one of the higher scoring factors of the Environmental category, and the average scores for the amount of natural and artificial lighting were close to the ideal. However, direct glare from the lights and from the sun and sky were noted as issues to be addressed.
We present observations from evaluation of internal environmental quality of industrial halls with priority on daylighting in combination with the integral lighting. The physical parameters related to indoor lighting in large industrial halls in winter and summer periods were analyzed using in situ measurements and computational methods. These are part of a comprehensive research on indoor environmental quality of industrial halls with the aims of saving energy and providing a comfortable environment for the workers while improving the productivity. The results showed that the procedures used for evaluation of residential or office buildings may not be used for industrial buildings. We also observed that the criteria of occupants' comforts for indoor industrial buildings may differ from those of other kinds of buildings. Based on these results, an adequate attention is required for designing the industrial buildings. For this reason, appropriate evaluation methods and criteria should be created. We found the measured values of daylight factor very close to the skylight component of the total illumination. The skylight component was observed on average 30% that of the measured daylight factor values. Although the daylight is not emphasized when designing the industrial buildings and its contribution is small, but it is very important for the workers psychology and physiology. The workers must feel a connection with the exterior environment; otherwise, their productivity decreases.
TIME-INVARIANT ANALYSIS OF INDOOR SPACE DESIGN IMPACT ON DAYLIGHT ILLUMINANCE
November, 2019
This paper assessed the hourly daylighting illuminance and light distribution of three categories of the classroom window design in four classroom spaces in Federal University Wukari, Taraba State on illuminance-based metrics under clear sky conditions for visual safety support of the space design. The categories of the classroom window designs were one-sided (West) window, two-sidedadjacent (South and West) windows and two-sided (North and South) opposite windows. Instrumentation design for data collection were A Garmin GPS 72H, Sunche model HS1010 digital luxmeter, a digital professional handheld LCD stopwatch, delectable marker pen,and generic 5m retractable measuring tape rule. The data was collected on a time-sequence basis at an hour interval from 8:00 am-5:00 pm on the students' work planes. The visual performances and safety of the time-varying illuminance data obtained and analyzed on the standard metric bins and a two-tailed weighting factor variable criterion within the range of Elower limit (100 lux) and Eupper limit (2000 lux) value considered as being useful and safe showed that the two-sided opposite window classrooms illuminance performance were relatively more useful and safer than that in one-sided window classrooms as well as the two-sided adjacent window classrooms. For the maximization of indoor space illuminance of classroom, two-sided opposite window design is recommended.
Sustainability, 2018
The aim of our research is to investigate the physical connection between light, perception, and information by means of an integrated methodological approach. The proposed method was used for sustainable lighting design aiming at light efficacy and quality, visual perception, communication, and energy saving. Three types of synergic measurement were carried out: photometric, colourimetric, and perception measurements. Starting from the results and the post-processing of photometric and colourimetric measurements on different light sources and fresco surfaces, by applying the eye-tracking technique for eye movement analysis of a people sample, entropy calculations were carried out. The results of observer perception and preferences, patterns of their visual scanning due to different LED (Light Emitting Diode) sources, were quantified by means of Shannon entropy calculation and, consequently, the information content of images that each light source can transmit. A new lighting proposal, based on the use of LED sources characterized by a spectral emission of light in strong compliance with surface colour and relevant transmission image content information was suggested and checked by transient simulations. Our proposal was based on sustainability because this concept is linked to developing perception and visual wellbeing, information, light communication, and lower energy consumption for maintenance, but especially for preventive conservation and the protection of works of art by means quality of light.
Daylight in Buildings and Visual Comfort Evaluation: the Advantages and Limitations
Journal of Daylighting, 2021
Exposure to daylight significantly affects the psychological well-being of occupants by diminishing headaches, eye tensions, or stress. Daylight penetration is a matter of collaboration between building façade and perimeter zones that can be controlled through façade design features. This study reviews available daylighting systems to block or redirect natural light inside the space and their overall performance. Adaptation found to be the main key feature of daylighting systems to improve their effectiveness in indoor environments. As the main implication of such systems on the visual comfort performance of occupants, a list of quantitative indices is studied based on their mathematical equation to outline their advantages and limitations. Findings revealed a lack of agreement on acceptable indoor illuminance thresholds for most of the indices and the absence of a reliable glare index in presence of sun within the view field of the occupant. Similarly, many green building certifications propose a specific criterion to assess view out but remained a challenge for future studies.
Lighting preferences in office spaces concerning the indoor thermal environment
2021
The accurate prediction of the visual comfort zone in an indoor environment is difficult as it depends on many parameters. This is especially the case for large compact urban areas in which the density and shadow from neighboring buildings can limit the accessible daylighting in indoor spaces. This paper investigates the satisfaction range for illuminance regarding indoor air temperature in office buildings and the significant parameters affecting this range in six office buildings in Tehran, Iran. Lighting comfort has been evaluated by a subjective survey (509 total responses) and field measurement. The questionnaires were filled out in 146 and 109 rooms in summer and winter, respectively. The results show that the illuminance should not be less than 550 lx, while illuminance between 600 and 650 lx provides the highest satisfaction level. The satisfaction with lighting level is affected by individual parameters such as age, type of activity, and environmental parameters such as window orientation, external obscurations, and season. A relationship was observed between lighting level satisfaction and thermal condition acceptance, and the overall comfort depends more on thermal conditions than the lighting level.