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Computer modeling and simulation are essential for predicting architectural solutions performance. When integrated into the design process; they are known as performance-based design. During the design process, fast analytical cycles are required. However, daylighting simulations are challenging due to computational processing and time requirements. This paper presents a comparative study of fast daylight simulation methods, two-phase, three-phase and path tracing, in a hypothetical commercial building located in Miami, Florida. Five types of static glass and one electrochromic glass were tested with six parametric models of a translucent horizontal shading device. Daysim was used as reference. The two-phase method produced results similar to the reference results with faster processing times for static facades. For dynamic facades, the path tracing method with the tested interface enabled faster simulations and parametric variations. However, the three-phase method yielded a lower average error. [ABSTRACT FROM AUTHOR]

Annual daylighting and point-in-time glare calculations depend on manipulating large matrices representing annual light levels and image pixels, respectively. Advances in computation speed have allowed modern green building standards like LEED, WELL, and EN 17037 to require annual daylighting calculations at a fine resolution across a building's floorplate. As parallel ray tracing speeds become faster and cameras increase in resolution, matrix manipulation itself has emerged as a bottleneck to delivering fast simulation results. This paper describes a how vectorized computation methods can be applied to annual daylighting simulation and high dynamic range (HDR) image processing. Vectorization allows a computer to perform simple operations on large amounts of data simultaneously. We use the NumPy library in Python to vectorize multiple steps in the calculation of spatial daylight autonomy and annual renderings for glare as example climate-based daylighting metrics, achieving a speedup of two orders of magnitude. We also show that NumPy can manipulate large HDR images with speedups for individual operations up to six orders of magnitude. [ABSTRACT FROM AUTHOR]

Natural lighting in office buildings is often affected by excessive solar heat gain and discomfort glare, and the transitional seasons are no exception. Therefore, addressing the issue of natural lighting in buildings has always been a challenge in developing shading control strategies. This study designed a model-based calculation method for shading blind control indicators. The method combines existing physical models for sky conditions, solar radiation, heat transfer, thermal comfort, glare, and illuminance calculations and incorporates modifications and additions. Additionally, an equivalent energy-saving model for shading was established. A shading blind control strategy balancing indoor light and the thermal environment with energy savings during transitional seasons was proposed. In transitional seasons, this method can eliminate 100% of glare, reduce discomfort illuminance duration by 81.3% and heat discomfort duration by 87.5% and save 81.3% of lighting energy consumption when air conditioning is used. By comparing the simulation results of an office building in Xi'an with the results obtained from this calculation method, the absolute error percentage was found to be 6.83%, verifying the reliability of the calculation method. Finally, the proposed control strategy was compared with common methods such as no blinds, end-angle control, and fixed-angle control to evaluate its performance in terms of daylighting, thermal comfort, and energy savings. The results showed that the control strategy proposed in this study has significant advantages with respect to various performance indicators. [ABSTRACT FROM AUTHOR]

Studies on the efficient use of daylight in sustainable architectural design and energy conservation are increasing. Indoor lighting methods include daylighting, artificial, and integrated lighting. Basic priorities in lighting are such as "effective use of daylight", "uniform illumination in space", "glare control", "visual connection with the external environment" and "daylight harvesting." Advanced contemporary systems include light shelves and light tubes. Light shelves consist of horizontal or slightly angled elements that can be applied to the inner and outer surfaces of the window openings, usually at eye level, to block the daylight or to reflect it to the ceiling, integrated with the facade, or added later. In this research, light shelves, which is one of the advanced daylighting methods, are emphasized. Daylight analysis method was carried out with the help of a physical model and computer simulation techniques using DiaLux software. To effectively utilize the daylight factor in the internal volume through light shelf, certain parameters such as the height and angle of the light shelf, date and time, and direction of the room's opening, play a crucial role. In daylight analyzes, these parameters were subjected to experimental testing both in physical models and through computer simulations. As a result of the comparison of the obtained data, alternatives that will provide the opportunity to benefit from daylight in the most effective way have been identified. The results obtained have unique value and widespread impact in terms of sustainable architecture and energy saving. The study's originality lies in its specific measurements of the latitude in which it is located, as it is the first time the study is conducted under Eskisehir's conditions. In addition, the examination of the advantages and disadvantages of the light shelf in specific combinations is another original side of the project. [ABSTRACT FROM AUTHOR]

Continual two-year measurements of daylight illuminance were performed in order to evaluate the daylighting of a model room. The key research idea was to study room orientation and its effect on daylight availability by using real measurements from a physical scale model. Firstly, differences between the illuminance in the north- and south-oriented rooms were compared. Secondly, a characteristic annual profile of the external horizontal illuminance data was determined. Finally, the median external diffuse illuminance data from measurements were compared with values based on the values recommended in the standard. The goal of the research was focused on the evaluation of a regional daylight climate model applicable for daylight evaluations. The results of the daylight illuminance measurements showed the importance of climatic daylight data for indoor daylighting in building design performance. [ABSTRACT FROM AUTHOR]

This article reports on the development, validation, workflow and implementation of a simplified method for evaluating the non-visual (melanopic) potential of daylight in typical side-lit rooms. The method is suitable for climatic areas with a dominant occurrence of cloudy skies. The non-visual daylight evaluation tool is based on a modified average daylight factor method. A simplified daylighting model improves the calculation of the vertical daylight factor and the passage of daylight through a vertical lighting opening. The proposed calculation method makes it possible to determine the illuminance of a vertical plane in the interior. The method is based on the uniform sky and the external diffuse horizontal illuminance at the location of interest. The outputs of the tool can also be used to quickly estimate visual levels of daylight. The article also proposes a classification of the availability of melanopic daylight in side-lit rooms, which is based on the outputs of the proposed calculation method. [ABSTRACT FROM AUTHOR]

Building geometry design decisions are important for energy efficiency and daylight performance. Sensitivity analysis, coupled with optimization, is an important approach to investigate and optimize building geometry in the early design stage. Incorporating skylights is an important daylighting strategy in commercial buildings; however, skylight-to-floor ratio (SFR) is often the only design variable evaluated in precedent studies. More design variables related to skylight geometry, clerestory geometry, skylight material, and building geometry need to be evaluated. This study investigates the skylight design of a 2000-square-meter commercial building. Eighteen design variables are evaluated according to their influence on building energy and daylight performance. One-at-a-time (OAT), linear regression, and Morris sensitivity analysis approaches are utilized to identify the most influential variables. Seven of the twelve building geometry variables and two of the six building material variables are considered as important. Then, a multi-objective optimization with genetic algorithms is processed to find out the optimal design solution. The three objectives are energy use intensity (EUI), daylight autonomy (DA), and daylight uniformity (DU). After the optimization, five candidate design options are picked from the Pareto front. Discussions are made on the features of these designs, and one design is selected as the optimal solution. [ABSTRACT FROM AUTHOR]

This study characterizes the transmittance behavior of structural light-transmitting concrete under natural sunlight. The experimentation involves the use of a novel test setup and a detailed analysis considering the variation and dependence on time of day, month of the year and seasonal variations. The test set consisted of 28 variations of fiber configurations, with two different diameters, spacing and bundling techniques used to increase the area of fibers while maintaining spacing to aid the placing of concrete without compromising on transmittance. The study provides a real-time observational understanding of the behavior of light-transmitting concrete, a result usually obtained by modelling and simulation. The statistical analysis helps in understanding the impact of various variables as well as their interrelationships, which can help in design optimization. Based on the behavior as well as the stipulations of standards, the applicability of the material to various structural applications has been identified. [ABSTRACT FROM AUTHOR]

Urban stream environments have been significantly altered through processes of colonisation and urbanisation. In Te Whanganui‐a‐Tara Wellington, Aotearoa New Zealand, there is growing interest in peeling back layers of the city to reconnect with waterways. More‐than‐human geographies can play a critical role in contributing to these efforts, guiding understandings of what it means to restore and live alongside urban streams. In our case study of the Waimapihi Stream, we explore one community's ideas and practices of restoration and how they envision a thriving place through the notion of stream daylighting. The Waimapihi shows us that restoration activities are both product and process of co‐creating an ontologically plural space for the renegotiation of what stream restoration means. [ABSTRACT FROM AUTHOR]

In order to clarify the temporal and spatial changes in the internal photothermal environment in an open-field agrivoltaic system (OAVS), this paper took the OAVS in eastern China as the research object and divided the internal area into the southern area, middle area and northern area, according to the spatial structure. Further, a photothermal environment test was conducted in the above three areas in the summer and winter. The results showed that the summer average daylight rate (Rm-avg) in the middle area was 66.6%, while the Rm-avg in the other two areas was about 20%, with no significant difference. In the winter, the light environment in the southern area was slightly better, and the Rm-avg in the above three areas was 26.4%, 24.7% and 19.7%, respectively. On the whole, the relationship between the thermal environmental factors and the solar radiation intensity was consistent. Further, a 3D model of an OAVS was established using Autodesk Ecotect Analysis 2011, and the internal light environment was simulated. Compared with the measured values, the relative error was less than 10%, which verified the reliability of the OAVS model. Then, the model was used to reveal the temporal and spatial changes in the light environment of the OAVS. The simulation results showed that the daylighting rate in the summer from the ground to the height of the fig canopy inside the system was 20.7% to 61.5%. In the winter, the daylighting rate from the ground to the height of the fig canopy inside the system was 17.7% to 36.4%. The effectiveness of the OAVS in reducing the level of solar radiation intensity depended on the time of day and the angle of the sun. At the spatial scale, due to the strong consumption of light by photovoltaic panels, there was a strong horizontal and vertical light environment gradient inside the system. In conclusion, the photothermal environment research of an OAVS based on Autodesk Ecotect Analysis 2011 can not only provide a basis for agricultural production and structural design such as span, height and the laying density of PV panels, but also expand its application to regions with different latitudes and longitudes and specific climates. [ABSTRACT FROM AUTHOR]

Daylight data are required for energy-efficient building designs. However, daylight is scarcely measured, making the luminous efficacy model an alternative. This paper presents a method for modeling vertical luminous efficacy (Kvg) using measured data from measuring stations in Hong Kong. The artificial neural network (ANN), support vector machines (SVM), and empirical correlations were proposed for modeling Kvg. Machine learning (ML) models like ANN and SVM were used because they offer more accurate daylight predictions and ease in explaining complex relationships between atmospheric variables. Also, ML was explored since it has not been used in earlier vertical luminous efficacy studies. Sensitivity analysis was also carried out to determine the relative importance of input variables used for developing the proposed models. Findings show that scattering angle and diffuse fraction are crucial variables in vertical luminous efficacy modeling. Furthermore, when all proposed models were used to predict vertical daylight, it was observed that the peak relative root mean square error (%RMSE) was less than 18.6%. The obtained %RMSE showed that all models provided acceptable performance when evaluated against the measured daylight data. Finally, the findings also showed that the ANN models outperformed the SVM and empirical models. [ABSTRACT FROM AUTHOR]

• A structural model for visual comfort in office spaces is presented and confirmed. • The priority of influential parameters is defined. • 17 influential variables were investigated simultaneously for overall visual comfort. • The importance and performance of parameters are defined. • The model is quantitatively validated for office spaces. Daylight quality in office spaces is an essential parameter that affects indoor environmental quality and significantly reduces energy consumption. Several individual, environmental, and physical parameters influence the visual perception of occupants. Therefore, visual comfort is a result of the combination and interconnection of all these factors. This study aims to evaluate and prioritize the factors that have a significant impact on indoor daylight quality, by using post-occupancy evaluation to examine how different variables affect human visual comfort by taking into account the simultaneous and interactive effects of these variables. A new modeling framework is constructed through partial least squares structural equation modeling (PLS-SEM) to evaluate the relationships among variables. The proposed model has 57.6% explanatory power for occupants' satisfaction with the lighting environment with R2 = 0.576. Additionally, analysis of the data using the Importance-Performance Map (IPMA) reveals the priority of relevant factors. According to the findings, among the 17 variables studied, horizontal and vertical daylight illuminance, glare sensation, distance from the window, and thermal satisfaction have the greatest impact on visual perception, in that order. Although the other factors studied are still important, in comparison with these factors, have less impact on the assessment visual comfort. Therefore, to improve the quality of office spaces with daylight and increase occupants' satisfaction, the focus should be on enhancing these five factors first. [ABSTRACT FROM AUTHOR]

The validated dynamic model of a parabolic trough power plant (PTPP) is improved by the combination of a new feedwater circuit (feedwater/HTF circuit) and a reference feedwater circuit (feedwater/steam circuit) as well as the development of the steam turbine model. Such design represents the first effort of research to utilize a dual feedwater circuit inside the PTPP to increase the power output in the daylight from 50 to 68 MWel and raise night operating hours at a lower cost. The purpose of increasing the operating night hours at a power (48 MWel) as in the reference PTPP is to get rid of the fossil fuel backup system and rely only on the absorbed solar energy and the stored energy in the molten salt. During daylight hours, the feedwater circuit is operated using Feedwater/HTF. In the transient period, the feedwater/HTF circuit will gradually be closed due to a decrease in solar radiation. Furthermore, the rest of the nominal feedwater mass flow rate (49 kg/s) is gradually replenished from the feedwater/steam circuit. After sunset, the entirety of the feedwater is heated based on the steam extracted from the turbine. The purpose of this improvement is to raise the number of nightly operational hours by reducing the nominal load from 61.93 to 48 MWel as a result of low energy demand during the evening hours. Therefore, a comparison study between the reference model and this optimization (optimization 2) is conducted for clear days (26th–27th/June and 13th–14th/July 2010) in order to understand the influence of dual feedwater circuit. The comparison indicates that the operational hours of the power block (PB) will be obviously increased. Moreover, this improvement reduces based on the fossil fuel system at night. As the last step, an economic analysis was performed on the costs of the referenced and the optimized PTPP as a function of the levelized energy cost (LEC). The results illustrate that the specific energy cost of a PTPP with 7.5 h of storage capacity is lowered by about 14.5% by increasing the output of the PTPP from 50 to 68 MWel. [ABSTRACT FROM AUTHOR]

Buildings sector being responsible for more than one-third of the overall energy consumption is growing rapidly. One of the top priorities of building designers is to minimize energy consumption. This communication presents a multi-framework-based approach to optimize dwelling conditions and energy efficiency in subtropical climatic conditions. In the present work, the thermal behavior of indoor air is assessed by using Ansys Workbench while the Grasshopper plugin of Rhinoceros 3D is used to evaluate the daylighting under different scenarios. The study also involves a survey with a sample size of 289 people to substantiate the various optimization strategies. Further, the work encompasses the validation of respective approaches by comparing the results with measured values. Based on the results, it has been observed that using a ceiling fan and air conditioner alongside during the summer season in subtropical climatic conditions provides better dwelling conditions and reduces cooling load by 20–30% in comparison with an air conditioner alone. While consciously utilizing daylight by ensuring minimal illuminance of 500 lx is having the ability to decrease the lighting load by approximately 27%. Further, the results obtained from the present investigation can serve as a basis for providing better dwelling conditions with optimized energy utilization. [ABSTRACT FROM AUTHOR]

Daylighting is one of the main factors among the features that determine the original space qualities in traditional houses. Illuminating the space with daylight also determines its ambience. Daylighting criteria should be considered among the features to be preserved in the usage decisions. In traditional dwellings in Anatolia, the main room is the most lavish room, which has projections and is surrounded by windows on three sides. Therefore, in the buildings which are conserved for reuse, the main room should maintain its original daylighting features. The aim of this study is to draw attention to the maintenance of daylighting features in the restoration decisions of traditional dwellings. Within the scope of the study, daylight performance of the main rooms of Kaçıklar and Zabunlar Houses selected in Kula, Manisa was evaluated. The daylight illuminance of the main rooms was measured during the four seasons; by calculating the ratio of the window area to the floor and wall areas, reflectance of surface materials and normal-normal transmittance of window glass were calculated. Results showed that daylight illuminance of the main room in Kaçıklar House was not sufficient for all four seasons, while it was in Zabunlar House. As a result, while the restoration decisions are developed, opening the closed window in the main room of Kaçıklar House, cleaning the paint on the top windows and and selecting a light-coloured wall finishing material will increase the reflectance value and will positively affect the daylight illuminance; in Zabunlar House, on the other hand, removing the existing wooden glazing in the sofa in order to increase the daylight provided through the sofa and increasing the reflectance value by choosing a light-coloured wall finishing material will increase the daylight illuminance of the main room. [ABSTRACT FROM AUTHOR]

• Realization of high flux transmission via PMMA plastic optical fibers. • Plastic optical fibers effectively avoid overheating under 4500 suns. • Combination of IR filter and heat absorbing glass for 780–2500 nm filtering. Daylighting system by concentrating and transmitting sunlight through optical fiber is an emerging technology of direct utilization of solar energy. In this work, a sunlight concentrating and transmitting system via plastic optical fibers was developed and investigated. This study addressed the overheating problem of plastic optical fibers under highly concentrated light irradiation. Polymethylmethacrylate (PMMA) plastic fibers have a strong absorption in the infrared band. The PMMA plastic fiber generates serious heat under highly concentrated light transmission, which leads to its overheating and burning. In this study, an incident light filtering method based on the combination of infrared filter and insulating glass is proposed. By filtering out the infrared band light with significant thermal effect, the PMMA plastic optical fibers are guaranteed to be within a safe working temperature range. Experiments demonstrated that the developed filter system can ensure the safe operation of PMMA plastic optical fibers at the concentration level of about 4300 suns. This shows that it is feasible to use low-cost plastic optical fiber for highly concentrated daylighting system. [ABSTRACT FROM AUTHOR]

Modern day building design projects require multidisciplinary expertise from architects and engineers across various phases of the design (conceptual, preliminary, and detailed) and construction processes. The Architecture Engineering and Construction (AEC) community has recently shifted gears toward leveraging design optimization techniques to make well-informed decisions in the design of buildings. However, most of the building design optimization efforts are either multidisciplinary optimization confined to just a specific design phase (conceptual/preliminary/detailed) or single disciplinary optimization (structural/thermal/daylighting/energy) spanning across multiple phases. Complexity in changing the optimization setup as the design progresses through subsequent phases, interoperability issues between modeling and physics-based analysis tools used at later stages, and the lack of an appropriate level of design detail to get meaningful results from these sophisticated analysis tools are few challenges that limit multi-phase multidisciplinary design optimization (MDO) in the AEC field. This paper proposes a computational building design platform leveraging concurrent engineering techniques such as interactive problem structuring, simulation-based optimization using meta models for energy and daylighting (machine learning based) and tradespace visualization. The proposed multi-phase concurrent MDO framework is demonstrated by using it to design and optimize a sample office building for energy and daylighting objectives across multiple phases. Furthermore, limitations of the proposed framework and future avenues of research are listed. [ABSTRACT FROM AUTHOR]

The issue of how to fully utilize natural daylighting of public buildings is one of the greatest practical objectives for lighting savings. The rapid and accurate prediction of the daylighting coefficient at the early design stage can provide a quantitative basis for energy-saving optimization. However, it is not comprehensive to determine the design parameters according to experience. The key problem that is still facing designers is the interoperability between building modeling and energy simulation tools. In this paper, an integrated approach using a dataset created by building information modeling and artificial neural network technology is developed for the fast optimal daylight factor prediction of large public spaces at the early design stage. According to this approach, the value of daylight factors is calculated for different windowsill heights, window heights and widths by Autodesk® Revit and Ecotect Analysis to form a dataset. With this dataset, an artificial neural network model is established using the backpropagation algorithm to predict the relevant design parameters. With their large interior spaces, the reading areas of the aboveground five floors in Chengdu University of Technology Library are selected to carry out the daylight factor experiment and rapid prediction. A total of 495 groups of experimental data are randomly divided into training and testing sets. The root mean squared errors are below 0.1, which indicates a high regression model fitting. A total of 225,369 groups of prepared data are used in the prediction model to obtain the optimal windowsill height (1.0 m), window height (2.4 m) and window width (2.1 m) for five floors in the case of the maximum daylighting coefficient. Finally, a smartphone app is designed to facilitate daylight factor prediction without any experience in modeling and simulation tools, which is simple and available to realize prediction visualization and historical result analysis. [ABSTRACT FROM AUTHOR]

• TDDs require smaller roof opening, provide light deeper than conventional skylights. • Evaluation of light delivery and visual comfort performance of TDDs under real sky. • Studied influence of TDD dome, diffuser, diameter and other factors. • Prismatic domes provide more rounded daily illuminance profile. • No visual discomfort detected. Tubular daylight devices (TDDs) require a much smaller roof opening than conventional skylights and, because of their highly reflective tube, they can deliver daylight farther away from the building envelope. This can provide lighting energy savings, increasing resilience in new and existing buildings. Different types and configurations are available amongst commercially available TDDs, including domes/diffusers with varying optical properties and the diameter of the TDD. This paper presents a comprehensive experimental evaluation of the lighting and visual comfort performance of multiple configurations of commercially available TDDs, varying dome type (prismatic and clear), diffuser type (Fresnel and prismatic), and diameter (53 and 35 cm), under a range of environmental conditions (different times of day/year, sky cover). Based on illuminance measurements, estimated lighting energy use is also presented. Results indicate that, for clear sky, light levels increase and energy use decreases with solar altitude (e.g., 16 Wh/m2 daily energy use intensity on a high maximum daily solar altitude (MDSA) day and 34 Wh/m2 on a low MDSA day) and TDD diameter (e.g., 34 Wh/m2 and 69 Wh/m2 for 53 cm and 35 cm TDDs, respectively, for low MDSA). The daily illuminance profile is more rounded for prismatic domes and has higher peaks for clear domes; this translates into a somewhat higher average daily useful daylight illuminance (DUDI) for prismatic domes (86 %) when compared to clear domes (80 %). No clear impact of diffuser type was apparent. Measurements indicated no discomfort glare for any of the conditions tested. [ABSTRACT FROM AUTHOR]

Daylight penetration significantly affects building thermal-daylighting performance, and serve a dual function of permitting sunlight and creating a pleasant indoor environment. More recent attention has focused on the provision of daylight in the rear part of indoor spaces in designing sustainable buildings. Passive Anidolic Daylighting Systems (ADS) are effective tools for daylight collection and redistribution of sunlight towards the back of the room. As affordable and low-maintenance systems, they can provide indoor daylight and alleviate the problem of daylight over-provision near the window and under-provision in the rear part of the room. Much of the current literature on the ADS pays particular attention to visual comfort and rarely to thermal comfort. Therefore, a reasonable compromise between visual and thermal comfort as well as energy consumption becomes the main issue for energy-optimized aperture design in the tropics and subtropics, in cities such as Sydney, Australia. The objective of the current study was to devise a system that could act as a double-performance of shade and reflective tool. The central aim of this paper is to find the optimum curve that can optimize daylight admission without an expensive active tracking system. A combination of in-detail simulation (considering every possible sky condition throughout a year) and multi-objective optimization (considering indoor visual and thermal comfort as well as the view to the outside), which was validated by field measurement, resulted in the optimum ADS for the local dwellings in Sydney, Australia. An approximate 62% increase in Daylight Factor, 5% decrease in yearly average heating load, 17% savings in annual artificial lighting energy, and 30% decrease in Predicted Percentage Dissatisfied (PPD) were achieved through optimizing the ADS curve. [ABSTRACT FROM AUTHOR]

Sunlight is a great substitute for indoor artificial lighting during the daytime but still isn't so viable because of the cost of fiber-based daylighting system and its efficiency. In this paper, we report the design and development of a cost-effective non-mechanical tracking-based solar concentration system using a combination of a large Fresnel lens, segmented mirrors, and segmented compound parabolic concentrator (SCPC) for indoor daylighting application. This system presents the three-stage collection of sunlight by means of extending the collection aperture vertically while keeping the horizontal area same. First one is the concentrated light from the Fresnel lens, the second one is the direct sunlight incident onto the CPC and the third one is the direct sunlight reflected from the segmented mirrors onto the CPC. Hence the light transported through this system is adequate for illumination purposes inside the room. The manufacturing of ideal CPCs through the moulding process is both expensive and complex, and it necessitates extreme precision. Therefore, a cost-effective and efficient segmented CPC is designed and developed using a highly reflecting mirror-polished aluminum sheet which works well compared to the ideal CPC. To transport concentrated sunlight inside the room a highly reflecting horizontal light pipe is designed and developed. The collimated light at the output is challenging therefore, we have coupled inverted CPC at the exit of segmented CPC in the system. Further, to guide sunlight deep into the rooms we have coupled the entire system with a rectangular light pipe. An efficient diffuser is coupled at the end of the rectangular light pipe to illuminate the room uniformly. Various optical parameters such as illuminance, color rendering index (CRI), and correlated color temperature (CCT) values are analyzed from the result obtained which shows that the system can efficiently transport sunlight deep inside the room throughout the day. Therefore, the proposed system is very much helpful for the sustainable development of a country. [ABSTRACT FROM AUTHOR]

Property disputes are frequent occurrences in rapidly urbanizing regions. Among the legal issues concerning building property rights, solar rights disputes are prevalent because text clauses on solar rights rely on diverse measurements or calculations. Moreover, previous studies on measuring solar rights addressed only the sunlight duration and neglected the daylight factor (daylighting coefficient), which is an integral component of solar rights. Therefore, this study proposes a 3D spatiotemporal model for effectively measuring solar rights by taking both the sunlight duration and the daylight factor into consideration. This model would be technologically valuable in avoiding or settling legal disputes. Taking the specifications of the solar rights of building property in China as a case study, the proposed spatiotemporal model clarifies the complete solar rights of residential units and is implemented by integrating a geometric model from CityGML with a property model, namely, the Land Administration Domain Model (LADM). Three real typical cases are adopted to show the applicability and benefit of the 3D spatiotemporal model in resolving legal property disputes. [ABSTRACT FROM AUTHOR]

The lightwell is an architectural solution to promote daylight into the internal spaces from the core of a building. The shaft configurations, such as geometry and reflectance can affect the performance of the daylighting entering the adjoining rooms under different conditions. This study aims to indicate the adequate architectural solutions to improve the daylighting performance of buildings with lightwells at three different southern latitudes. From a base model of 6-stories building, alternative cases were parametrically simulated using Rhinoceros, GrassHopper and ClimateStudio software. From variations in the lightwell geometry and walls reflectance, the cases were analyzed considering the lighting metrics UDI and sDA300. Results demonstrate that the daylighting is adequate on the floors near the top of the building and weakens towards the base of it. In Macapá, São Paulo and Chile, the sDA values reach 100% on the top floor, but only 3% on the first floor. It was also observed that materials with high diffuse reflectance on the shaft is more efficient in improving the daylighting performance than increasing its geometry. This research presents early-design guidance to inform architects and policymakers when considering the exploitation of daylight by the use of the lightwell. [ABSTRACT FROM AUTHOR]

A novel architectural typology of buildings is proposed with special transmission of each window without the use of additional daylight shading/redirecting devices. Minimum transmission at a preset time and self-regulated transmission at the rest of the time, adapted to the sun's trajectory, are achieved due an optical filter having two thin-film gratings with alternating transmissive and chromogenic strips. The building typology algorithm was realized by calculating the geometric parameters of grating filters for various facades and their temporal characteristics of direct light transmittance. The results demonstrated the minimization of transmission at the preset time of day, and acceptable filter operation at other times, as also validated by daylighting and glare metrics evaluation. A smart window with grating filter can partially or completely block direct sunlight and let in diffused light, unlike other versions of smart technologies that have been developing rapidly in recent years. The ergonomic, environmental, and aesthetic properties of such a smart window are improved by the absence of additional devices. This typology has potential applications, especially in office and industrial buildings due to the need for sun protection during the daytime, as well as in buildings with curved facades with continuous azimuth changes. The proposed architectural typology of buildings with special characteristics of direct light and solar transmission of each window due to the use of the novel grating optical filter, the theoretical basis for its implementation and the results obtained indicate potential prospects for application in office and industrial buildings with the demand for sun protection, especially for buildings with curved facades. This approach provides an optimized light transmission capacity of each window without the use of additional daylight shading/redirecting devices and improves the ergonomic, environmental and aesthetic properties of the window and the room. For the practical use of the proposed typology of buildings, in future work it is planned to study in detail the annual performance of the window filter, evaluate the economic aspects and create a computer program convenient for architects that allows calculating all the necessary individual parameters of all windows of the building. [ABSTRACT FROM AUTHOR]

Increasing demands for full-glazed façades have motivated designers/researchers to propose advanced control strategies for dynamic shading systems to mitigate the negative impacts of excessive sunlight penetration into interior spaces. Nevertheless, in line with the latter, outside view is commonly obstructed as a result of utilizing conventional shading systems including Venetian blinds. This is primarily the consequence of conventional systems' lack of flexibility to respond appropriately to occupants' requirements and the sun's changing orientation. This paper presents the virtual prototype development of a Multi-layer blind system through a brute-force algorithm. It emphasizes proposing a customizable and affordable complex shading system with advanced control strategies for multiple building typologies. The research intends to improve visual comfort (daylight and glare) and maximize unblocked window view in a single office room located in Tehran. Furthermore, the control system was developed based on a combination of the cut-off and a glare protection control strategy. Concerning the cut-off control system, the slat angles change to block direct sun radiations, and then, if needed, the position of the front slat, named 'View slat', changes to avoid discomforting glare. In conclusion, the proposed prototype could improve daylight performance by up to 44% and maximize unobstructed outdoor view by approximately 47% in an almost glare-free zone. Finally, the usage of swarm intelligence could significantly improve the performance of the proposed prototype by determining which blind and how they should respond to environmental changes and occupants' requirements. Abbreviations: AFs: Adaptive Façades; OF: Openness Factor; OCF: Openness Curvature Factor; MLBS: Multi-layer Blind System; RML: Relative Maximum Luminance; GRV: Glare Response Vote; DA: Daylight Autonomy; Ev: Vertical eye illuminance; sDA: Spatial Daylight Autonomy; WPI: Work-plane Illuminance; DF: Daylight Factor; WFR: Window-to-Floor area Ratio; DGP: Discomfort Glare Probability; DGI: Discomfort Glare Index; UDI: Useful Daylight Illuminance; WPI: Work-plane Illuminance; GSV: Glare Sensation Vote; IV: A numerical score of the interest of a scene, assessed by a group of subjects; DGPs: Daylight Glare Probability simplified; cDA: Continuous Daylight autonomy; PGSV: Predicted Glare Sensation Vote; UDI_a: Useful Daylight Illuminance achieved; GSVs: Glare Sensation Votes [ABSTRACT FROM AUTHOR]

It is generally accepted that light is essential for visual perception, but it also has a range of non-visual effects on humans. Daylight is involved in the regulation of circadian biological processes, neuroendocrine and neurobehavioral human reactions. Current trends in the creation of the building environment and the modern lifestyle reduce the exposure of most people to daylight. In this article, we ask the question of what amount of daylight should be in the living rooms of apartments in order to ensure the conditions for vision, for the stimulation of non-visual effects and for visual well-being. In the article, older building regulations regarding the design of the size of lighting openings in building envelopes are confronted with current standards and knowledge of chronobiological research. The newly proposed criteria for daytime lighting of the interior spaces of buildings are analyzed, especially from the point of view of a sufficient degree of ensuring the stimulation of the circadian rhythms of their users. [ABSTRACT FROM AUTHOR]

In 2020, an international project on residential lighting started and was implemented in four countries (Poland, Sweden, UK and Turkey). This article presents the results of a survey carried out in Poland, in the winter term between November 2020 and January 2021. A total of 125 Polish residents (59 women, 65 men, one person did not wish to specify gender) participated in the survey. A variety of data was collected on the respondents and their assessments as well as on their satisfaction with day- and artificial lighting in residential living spaces. The results from questionnaires were analyzed with STATISTICA 13.3. Descriptive statistics and Spearman rank order correlations were adopted to identify the light-related aspects, lighting patterns, and respondents’ perception of day- and artificial lighting conditions in living areas. The results revealed that satisfaction with daylighting in the living area, both in summer and winter, was significantly correlated with daylighting level, daylighting uniformity, sunlight exposure and view-out. The results also revealed that satisfaction with artificial lighting was significantly correlated with artificial lighting level, artificial lighting uniformity and color rendering. The results provide valuable information on lighting and factors that influence the luminous environment in residential living spaces. [ABSTRACT FROM AUTHOR]

• An optical fiber daylighting system (OFDS) is implemented for an indoor farm, which allows addressing costly issues and achieving high efficiency. • An optimal design of the OFDS along with the various distances between the focal area and the optical fiber. • A concentration ratio of 140, optical efficiency of ∼19 % in simulation and ∼16 % in practice is demonstrated. • Energy saving can reach 54.3% on a sunny day and 38.9% on a cloudy day in an outdoor test. • Using the proposed OFDS helps the plant to grow better compared to using only LED. Optical fiber daylighting technology offers an effective path to deliver sunlight to an indoor farm that requires high energy consumption for illumination and a total visible spectrum for plant growth. However, the high cost of this technology can be seen as a drawback. In this study, the optimized daylighting system based on plastic optical fiber for indoor farm application is devised toward large-scale illumination with high efficiency and low cost. The proposed system comprises of a Fresnel lens array as a sunlight concentrator and plastic optical fiber bundles as a light transportation medium. Rather than previously common designs, we investigated the concentration properties of a non-imaging optics device – the Fresnel lens to find the optimal configuration of the system. Optimizing concentration ratio, optical efficiency, and overheating of an optical fiber daylighting system (OFDS) for the indoor farm application is carried out by simulation (LightTools software) and verified by experiments. The system design allows replacing the costly and sophisticated heat dissipation in conventional OFDS with only a UV-IR filter. The OFDS prototype is fabricated and tested in outdoor conditions. Results show that the proposed system archive concentration ratio of 140, the optical efficiency of ∼19 % by simulation, and ∼16 % by practice. Daylighting performance investigation on the installation of the prototype in the indoor farm demonstrates that energy saving can reach 54.3 % on a sunny day and 38.9 % on a cloudy day. Using proposed OFDS helps the plant to grow better than using LED only. Reliability tests and cost analyses show that our results provide an essential breakthrough for the application and commercialization of large-scale optical fiber daylighting technology for indoor agriculture. [ABSTRACT FROM AUTHOR]

The present research aims at promoting the stability and applicability of a hybrid daylighting system combining daylight and artificial light, which eventually enables a constant and pleasant luminous flux of the mixed light delivered by a terminal device installed indoors. That is, the present system allows a constant amount of luminous flux through its terminal device similar to an electric lamp, demonstrating its energy efficiency as well as comfortableness. The system effectively combines two different types of light, as solar rays are collected by a solar tracking sun light collector. The mixed light is transmitted indoors by optical fiber cables all the way to terminal devices installed indoors and discharged as needed. This feature enables the utilization of daylight to its full capacity, promoting solar availability. In this study, the photometry of hybrid lighting was experimentally measured and analyzed by using a spectrometer for different portions of sunlight when maintaining a constant luminous flux of mixed light. The effectiveness of hybrid lighting was explored for a number of cases in actual conditions, and the system was capable of delivering a constant illuminance of 1200 lux on a plane located 1.1 m away from the terminal device (light emitter). Finally, the system was installed in a test cell to verify its effectiveness for indoor illumination. [ABSTRACT FROM AUTHOR]

• Optimisation of perception with natural and artificial spectrum. • Daylight enhances the perceptual experience and provides it with context. • Complex lighting design measures in the Sistine Chapel. • Daylight in the Sistine Chapel does not generate profiles of conservation risk. This work provides a dual approach to the study of natural light inside the Sistine Chapel, of a purely quantitative type (measurements of absolute values) and a linked to perception aspects (spectral measurements), in the context of the great artificial lighting project implemented in 2014. The impossibility of proceeding with standard illuminance measurement instrumentation led to an alternative approach based on the fundamental relationship between illuminance and luminance on Lambertian surfaces; a graphical-experimental method of acquiring the reflection coefficients of Sistine paintings was developed to supplement in situ luminance measurements. The quantitative study was the starting point for qualitative reflections on light in order to investigate the opportunities and criticalities of daylighting: criticalities attributable to possible perceptual imbalances between different parts of the visual field and opportunities attributable to the genius loci which can be highlighted by the connection with the external light environment and its variability over the course of the day and the seasons. The concept of the naturalness of the lighting environment was investigated as a function of the variability of some quantitative variables (illuminance, luminance) and qualitative variables (emission spectrum and correlated parameters: CCT correlated colour temperature, CRI colour rendering index) related to light and variables linked to the effect of light on the colours of the frescoes (CIE coordinates, SDCM standard deviation of colour matching). The method can be applied to any confined space and produce useful results for the optimisation of exhibition spaces or, more generally, spaces characterised by the coexistence of requirements for use and conservation with natural and/or artificial light. [ABSTRACT FROM AUTHOR]

Buildings in India consume over one-third of the country's total electricity consumption and out of which about 28% and 25% are accounted for lighting energy in the residential and commercial buildings, respectively. Passive daylighting system using tubular daylight-pipe is a promising technique to save lighting energy by illuminating deep building interiors that have no daylight access through exterior windows. In this study, an innovative daylight-pipe has been designed and developed for enhanced daylighting performance by optimizing configurations of single and dual reflectors at its receiver. A detailed daylight assessment has been carried out using controlled experimentation while varying the reflectors position and orientation inside the hemispherical receiver of the daylight-pipe. It has been found that the single reflector oriented toward south has the best performance with a light transmission efficiency of 35.6%. Furthermore, monthly electrical energy savings due to the advanced daylight-pipe along with various supplementary electrical lighting options such as incandescent bulb, compact fluorescent lamp (CFL), and light emitting diode (LED) were estimated and compared for various climatic locations of India. From these evaluations, a lighting energy saving up to 23% has been observed in the summer month of May for temperate climate of Pune and hot-dry climate of Jodhpur. [ABSTRACT FROM AUTHOR]

Buildings in India consume over one-third of the country's total electricity consumption and out of which about 28% and 25% are accounted for lighting energy in the residential and commercial buildings, respectively. Passive daylighting system using tubular daylight-pipe is a promising technique to save lighting energy by illuminating deep building interiors that have no daylight access through exterior windows. In this study, an innovative daylight-pipe has been designed and developed for enhanced daylighting performance by optimizing configurations of single and dual reflectors at its receiver. A detailed daylight assessment has been carried out using controlled experimentation while varying the reflectors position and orientation inside the hemispherical receiver of the daylight-pipe. It has been found that the single reflector oriented toward south has the best performance with a light transmission efficiency of 35.6%. Furthermore, monthly electrical energy savings due to the advanced daylight-pipe along with various supplementary electrical lighting options such as incandescent bulb, compact fluorescent lamp (CFL), and light emitting diode (LED) were estimated and compared for various climatic locations of India. From these evaluations, a lighting energy saving up to 23% has been observed in the summer month of May for temperate climate of Pune and hot-dry climate of Jodhpur. [ABSTRACT FROM AUTHOR]

Harnessing daylight for energy-efficient designs requires the availability of daylight illuminance data. In the absence of measured daylight data, deriving daylight using the luminous efficacy model is an alternative. This paper presents an approach for modeling diffuse and global luminous efficacies using accessible measured climatic data. The methodology explored machine learning, sensitivity analysis and empirical modeling approaches. Twelve (12) luminous efficacy models were proposed. These models consisted of six artificial neural networks (ANN) and six empirical models. All models also cover the all-sky, overcast and non-overcast sky conditions. The intent of using ANN lies in the need for more accurate daylight predictions and its ease in explaining complex relationships between complex atmospheric variables. Findings from the study show that diffuse fraction is crucial in global and diffuse luminous efficacy modeling. Furthermore, the performance of all models was statistically assessed, and the results show that all twelve proposed models could offer acceptable predictions of daylight. In particular, the ANN models outperformed the empirical models. [ABSTRACT FROM AUTHOR]

Building-integrated photovoltaic (BIPV) systems allow solar panels to perform additional functions beyond energy generation for buildings, such as regulating interior lighting conditions and incoming radiative heat. However, optimizations of BIPV solar shades generally do not consider all of these factors, instead often focusing on power production alone. In this work, we explore a design framework for optimizing the configuration of BIPV shading devices to maximize a combination of power generation, interior daylighting quality, and radiative heating and cooling loads. This is applied to a simple room in five different locations and climates, as well as a case study of an office building. The low computational cost of this model allows for the full mapping of the influence of all design parameters on the value of the system, while demonstrating less than 7% error in predicting the performance of a benchmark experimental system. It is observed that the location and building geometry have significant influences on the relative values of heat, daylighting, and power production, with the overall combined value varying by up to 40% between the compared climates. The optimal design in many locations depend on user preferences as well, with many efficient solutions possible for varying trade-offs between the values of natural light vs. energy savings (a difference of up to 50%), as well as the system upfront cost vs. performance, further reinforcing the importance of tailored building-specific design for BIPV solar shades. • A model to optimize power, heat, and lighting quality of solar shades is developed. • Geometry and empirical models are combined to simulate shade performance. • Full design configurations of louvered shades are optimized. • Both beneficial and detrimental aspects of heat and light are critical to consider. • Optimal designs depend strongly on specific of both the location and building. [ABSTRACT FROM AUTHOR]

• A novel photochromic (PC) film was developed and tested for smart windows. • Building integration in a standard medium office building was modelled. • Energy saving were assessed, comparing PC glazing with standard compliant glazing. • Up to 4 MWh/year of energy saving and 40% of visual comfort increase were reached. • The dynamic behaviour of the PC film is the best choice for visual comfort. The study of chromogenic materials and systems is particularly promising for innovative, transparent building envelopes, with thermo-optical properties adaptable to surrounding environmental conditions. This work spots light on the multiple effects of photochromic glazing on the energy consumption of buildings and on the impact that such technologies would have on the visual comfort of occupants. To our knowledge, this is the first work dealing with building integration of spirooxazine-based photochromic films. This experimental and theoretical work aims helping to fill this gap by reporting the results of a study concerning the spirooxazine photochromic molecules, integrated in transparent matrices of polymethylmethacrylate. This work discloses the potential of specific photochromic materials, especially as a function of spectral peculiarities. The figures of merit of this technology have been studied by assuming its integration in an ideal multi-storey office building, and by studying the effects in terms of energy consumption and visual comfort and proposing a comparison with several static commercial glazing technologies. The photochromic glazing demonstrated to offer significant reduction of energy use for cooling, compared to a clear glass (with yearly saving of 4079 kWh, on the Southern facade), and for artificial lighting (with a saving of 3711 kWh), if compared to the commercial solar control glazing. Furthermore, the dynamic behaviour of the photochromic glazing represented the best choice in terms of visual comfort. [ABSTRACT FROM AUTHOR]

The impact of building sector on carbon mitigation has prompted an increased focus on the energy performance of the built environment. Conventional buildings often suffer from a decoupling effect between their static behaviour and the dynamic stimulus of external environment, which can affect energy performance. Therefore, there is a growing awareness that dynamic façades hold great potential for delivering substantial improvements in energy efficiency, enhancing thermal comfort and lighting conditions. The current study, targeted for architects, building designers and researchers, analyses the main trends and findings in dynamic façades research over the last five years, with a specific focus on improving three performance indicators: thermal comfort, energy efficiency, and daylight performance, through a bibliometric analysis and a systematic review. The research also explores the influence of climate and thermal inertia on these findings. Responsive systems have emerged as the primary focus of the research. Although less explored, adaptive dynamic façades have proven to be highly effective in improving overall performance. Moreover, climate zone analysis revealed that temperate climates were prioritized for dynamic façades research and demonstrated remarkable improvements in daylight performance, while arid climates can be distinguished for the enhancements in thermal comfort and energy efficiency. Concerning building thermal mass, there is a predominance of heavyweight solutions, as they reveal considerable advancements across the three performance indicators. Lastly, large-scale experiments are lacking because most studies are heavily dedicated to simulations and modelling. This highlights the need for additional research to bridge the gap between digital models and in-field experimental tests. • Bibliometric analysis and systematic review on dynamic façades (DF) in buildings. • Trends and findings, over the last 5 years, on DF systems research. • Focus on improving thermal comfort, energy efficiency, and daylight performance. • Influence of climate zones and thermal inertia on DF performances. • DF are growing in popularity and diversity, improving building overall performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extensive literature review on digital daylighting simulation and visualisation tools. • Digital tools empower daylighting design while confronting uncertainties. • Identified five main key themes in the application of digital tools in daylighting studies. • Examination of the input, computation, output, and feedback stages in daylight simulation. • Addressing challenges in the adoption and validation of visualisations for daylight analysis. Cultural and technological evolution have profoundly transformed architectural simulation and visualisation, revolutionising how architects communicate and execute projects. The integration of digital tools, in particular, has advanced building behaviour prediction and decision-making capabilities during the design process, playing a pivotal role in promoting benefits for sustainable building design. However, inherent uncertainties within daylight simulation and visualisation can significantly impact the precision and credibility of the obtained results. The objective of this literature review is to examine challenges related to accuracy and validation complexities when employing digital tools in daylighting studies. However, in assessing the quality and accuracy of models, it's crucial to consider their suitability for the intended purpose at various stages of design or research. This necessitates an initial overview of how digital tools are currently applied in daylighting studies, which helps to understand the goals of these models and ensure they are aligned with their intended applications. To address this, a systematic search conducted on the Web of Science (WoS) database yielded 1,441 studies, of which 1,102 were found relevant and employed digital tools for daylight analysis up to March 2023. This thorough analysis identified five primary thematic areas in the use of digital tools for daylighting research: Optimisation (49%), Calculation methods (17%), Assessment (13%), Accuracy (10%), and Decision-making (8%), collectively compromising 97% of the analysed articles. We subsequently concentrated on two pivotal areas, 'Calculation Methods' and 'Accuracy', to undertake a qualitative analysis of the discussed challenges related to accuracy linked to three main aspects: Input data, Computational process, and Output. The discussion further delves into the significance of the feedback step within this process, highlighting the complexities of validation and reviewing pertinent examples from the analysed studies. In conclusion, for those involved in education, research, and practice within the realm of (day)lighting analysis, grasping the nuances of these challenges is crucial to making more informed design decisions, particularly in Assessment and Optimisation areas, which represent a significant 62% of daylighting studies. As the field of architecture progresses, tackling these challenges becomes essential to maintaining the precision and trustworthiness of digital tools in daylighting studies, thereby contributing to the advancement of sustainable building design. [ABSTRACT FROM AUTHOR]

Due to their significant impact on worldwide energy consumption, buildings have emerged as the primary focus of current studies on the subject of energy conservation. Glass buildings are becoming increasingly popular due to their many desirable characteristics. The basic clear glass, however, is transparent to more heat and light, causing thermal and visual discomfort. The glazing application in this research makes use of three organic phase change materials (PCMs organic mixture of 21, 30, and 35 °C). The organic mixture PCMs were stuffed into the space between glass panes of double-pane glazing units (DUs) and are explored for solar-visible characteristics, solar heat inputs, cooling and heating operating costs, annualised cost savings, payback time, and natural illuminance in the two climates of India (Vellore and Delhi). The results obtained by the three proposed PCM glazings are compared with conventional DU. To facilitate the numerical methodology of calculating heat gain, operating costs, and cost savings, a MATLAB code was developed. A model of the building's ground floor and first floor was created utilising the Design-Builder, and then the model was run through the daylighting simulation tool to estimate the natural illuminace in the interior. In comparison to PCM glazings, conventional DU has a high transmittance and a low absorption. Among the studied proposed glazings, OM30(L) in its liquid state had shown the greatest reductions in heat input of 238.96 kWh and 208.5 kWh in the Vellore and Delhi climates, respectively. When compared to composite estimates, OM30 has performed admirably in hot climates. When placed in the south orientation, OM30 glazing has recorded the lowest annualised operating cost of 4.33 $/m2 in the Vellore climate. The highest cost savings of $2142.59 was recorded by OM30 in hot climates. Among those studied glazings, conventional DU, OM21(L), and OM30(L) glazing allowed adequate natural illumination in nearly all interior spaces, whereas solid-state PCMs (OM21(S), OM30(S), and OM35(S)) have blocked the interior's natural daylight. [ABSTRACT FROM AUTHOR]

• Influences of the transient daylight fluctuations on building are quantified. • It requires 140–700 h/year lighting duration due to the daylight instability. • It requires 5–17 min lighting duration to prevent each potential on/off switching. • Daylight instability is not symmetric in east and west spaces of the building. Fluctuations of daylight can cause uncertainties in evaluating its accessibility for building design and optimization tasks by the time-averaged solar and daylight data in hourly interval. This study thus investigates the transient daylight fluctuations and their consequences on the electric light that operates under the typical dead-band and time-delay controlling methods for a hot and humid subtropical region. We quantified the duration and its occurrence probability of the electric lighting operation due to the daylight instability with typical lighting control methods, and its correlations with the weather condition. For the controlling methods under study, results show the instability-associated lighting duration ranges from 140 to 700 h per year. This length account for 3.84% to 19.18% of the office hours, and is comparable to the period length with indoor illuminance below 450 lx during the day. This operation length is expected to be highest in cloudy condition, roughly taking 100 min per day, much higher than the overcast and clear conditions with around 30–40 min. The temporal lengths per day under dead-band and delay methods are less than around 50, and 130 min for more than 80% cases. The findings are essential to the accurate evaluation of daylight performance in buildings especially for buildings with unstable and cloudy weather conditions. [ABSTRACT FROM AUTHOR]

• This study focused on the development of a fixed dielectric daylighting louver. • A compact daylighting louver was developed for installation on side windows. • 500 lx and increased desktop illuminance was maintained at 6 m from the window. In this study, a stationary dielectric daylighting louver was developed based on the concept of the Köhler integrator. The developed daylighting louver, which is intended for installation on side windows in mid-latitude areas, such as Japan, is compact and easy to maintain. It was designed to collect sunlight at a solar-profile angle between 20° and 80°, and distribute it with a pitch higher than the horizontal of the room. As the daylight controlling principle, the concept of the Köhler integrator was adopted to capture low-altitude sunlight at an angle between 20° and 50°, corresponding to autumn through spring. The design procedure of the louver and its performance assessment using computational simulations and scale model experiments for office spaces with daylighting louvers installed on a south facade window is presented. The results confirm that 500 lx and more desktop illuminance are maintained at 6 m from the window with only the daylighting device in each season. They also confirm that the high desktop illuminance is maintained even during summer, when the incident angle is large, and the sunlight is difficult to capture. [ABSTRACT FROM AUTHOR]

The role of regulation in fostering or hindering sustainable development has been largely discussed. Yet, empirical studies on how to act in reviewing and modifying normative structures seem to be lacking within the academic debate. This work presents the experience undertaken by the research center FULL at the Politecnico di Torino (Turin, Italy), in supporting the local Municipality to simplify, disambiguate and redefine the current environment/energy regulation system. The paper particularly focuses on the methodological approach utilized to review rules in relation to daylighting in the local Energy Annex Code. This document contained mandatory and voluntary requirements and includes daylighting among the voluntary ones, through the average Daylight Factor DFm. It also addressed the window design through the RAI (Ratio Aerial Illuminating, defined as window area to room area ratio). The Municipality reports that building practitioners underuse the daylighting practice based on DFm, rather relying on RAI, because of its simplicity. Consequently, the Municipality gave mandate to FULL to define a new daylight indicator, to be included among mandatory requirement and meant to be more accurate than RAI but simple enough to promote its application. For this purpose, the 'RAI-enhanced' indicator was defined, as a function of: (i) glazing area Sg; (ii) glazing visible transmittance Tv, (iii) floor area Sfloor; (iv) obstruction angle α, considering buildings ahead of window, overhangs, and loggias. Based on the results, the paper explains how the daylighting part of the energy regulation system was informed and reviewed in the case of the Municipality of Turin. [ABSTRACT FROM AUTHOR]