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Kinetic facades with various geometric models perform remarkably well in response to changing outdoor conditions. Therefore, their performance in controlling interior daylight could be optimized and balanced. This study examines the receipt of natural light using kinematic models with different movement and geometric patterns for a 90% window-to-wall ratio (WWR) facade that faces cardinal directions in an office building in Tehran. To evaluate daylight reception, 15 kinematic models, which include some of the most well-known ones that have not been studied previously, have been simulated using the Grasshopper tool, Honeybee and Ladybug plugins, and Python. First, the room without any shading devices in the cardinal directions was simulated. Then, the effect of various kinematic models on the interior illuminance was investigated using various daylight metrics. The studied kinematic models were applied to windows on the south, west, and east facades. Then, the optimal kinematic model was suggested for each facade. A facade with a rotational kinematic model and a horizontal axis with a rectangle geometry performs better in terms of controlling daylight. Practical Applications: Kinetic facades exhibit unique capabilities in adjusting to changing environmental conditions, which include natural lighting. By comparing these facades, we could optimize their function to enhance natural lighting within interior spaces. This study investigates the application of moving facades on the south, west, and east walls of an office building in Tehran. Using simulation methods, the efficiency of daylight availability in indoor spaces using a dynamic facade approach is evaluated. Initially, this study explores various types of moving facades and examines key daylight performance indicators. Based on the data, 15 geometric and dynamic models of moving facades across the three wall orientations were studied. Then, the most efficient geometric and movement patterns for the facades in each orientation are presented. The findings indicate that a horizontal movement pattern combined with a rectangular geometric design outperforms the other geometric patterns for natural lighting for office buildings in Tehran. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue on lighting in buildings. The issue covers various research papers on topics such as integrative lighting, indoor lighting, and daylighting. The papers explore the impact of lighting on occupant well-being, performance, and comfort, as well as the effects of lighting color on emotions. The research also investigates the use of sensors and advanced controls to optimize energy efficiency while meeting occupants' needs. The document concludes with a call for papers for a follow-up special issue on lighting in buildings. [Extracted from the article]

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]

In this field study, we examined the impact of human-centered lighting on an open-plan office environment, involving the participation of sixty office workers. The objective was to investigate the effects of the Circadian Stimulus (CS) and Equivalent Melanopic Lux (EML) metrics. This study took place at Istanbul Technical University in Istanbul, Turkey. The office was equipped with single Correlated Color Temperature (CCT) light emitting diode (LED) sources, featuring two different light beam distributions: Direct Suspended Linear (L1) and Direct and Indirect Suspended Linear (L2). To minimize energy consumption, we proposed simulations for a suspended individual lighting system. The office workers were invited to complete visual cognitive performance tests, proofreading tasks, and the Karolinska Sleepiness Scale (KSS) test to measure alertness. Additionally, participants were asked to provide feedback on the comfort criteria associated with the designed human-centered lighting concept. The preliminary findings from part 1 of this field study shed light on the potential of office lighting modifications in enhancing energy efficiency and meeting the standards set by WELL v2 2023 Q4 and UL Design Guideline 24480 (2019). Part 2 of this study will further optimize the proposed lighting quality concept to determine the most suitable individual lighting solution for office workers. [ABSTRACT FROM AUTHOR]

Daylight can contribute to substantial reductions in the energy consumed by artificial lighting applications. However, issues such as visual comfort, illumination intensity, and availability represent major issues when daylight is relied upon to illuminate buildings. There are many technologies that are used to control received sunlight and minimize its side effects. The placement of solar film sheets on window glass is a common and popular method utilized in many buildings to minimize electric lighting energy consumption without causing undue visual discomfort to occupants. To examine the practicality of this application and its effect on room lighting, a modern office was selected in which to conduct this field study. Two measures were used to evaluate this technique: firstly, field measurements and their comparison to the specified standard illumination levels; and secondly, a short-form questionnaire survey conducted to obtain occupants' opinions of the office lighting. Actual measurements were conducted in the selected office spaces, with and without applying solar control film coating on the window glass. Indoor luminance levels and lighting comfort were systematically recorded and analyzed. The findings of this study show that using a solar film with a visible light transmittance of 50% can achieve savings in energy consumption of up to 33% if utilized as part of an integrated lighting system. [ABSTRACT FROM AUTHOR]

Exposure to natural daylight benefits human well-being, alertness, circadian rhythms and sleep. Many workplaces have limited or no access to daylight. Thus, we implemented a light-panel ("Virtual Sky"), which reproduced nature-adapted light scenarios. In a laboratory office environment, three lighting scenarios were presented during the day: two lighting conditions with nature-adapted spectral light distributions, one with static and one with dynamic clouds, and a standard office lighting condition. We compared the impact of the three lighting scenarios on subjective and objective measures of alertness, cognitive performance, wellbeing, visual comfort, contrast sensitivity, and cortisol levels in 18 healthy young male volunteers in a within-participant cross-over study design. We found no evidence that an 8-h lighting scenario with static or dynamic clouds during the waking day (9am-5pm) was associated with any significant effect on objective and/or subjective alertness, cognitive performance and morning cortisol concentrations compared to standard workplace lighting. However, the dynamic light scenario was accompanied with lower levels of perceived tensionafter completing cognitive tasks and less effort to concentrate compared to the static lighting scenarios. Our findings suggest that apart from smaller effects on tension and concentration effort, nature-adapted lighting conditions did not improve daytime alertness and cognitive performance in healthy well-rested young participants, as compared to standard office lighting. [ABSTRACT FROM AUTHOR]

This study proposes context-aware lighting presets for the office lounge based on user behaviour. We explored five kinds of optimised light scenarios: empty, relaxation, discussion, chatting and party, while matching them with patterns of user behaviours. Firstly, we designed lighting solutions for each context through expert interviews. Using these, we developed an algorithm that detects the number of users, their movement and their sound volume using a camera and microphone and suggests appropriate lighting settings based on this data. Then, we implemented the algorithm in two types of office lounges. Finally, user assessments and interview results confirmed that the adaptive lighting preset enriched users’ experience. We also discussed the challenges for better implementation. [ABSTRACT FROM AUTHOR]

The discovery of intrinsically photosensitive retinal ganglion cells in the eye and their interaction with melatonin has shown that light has significant effects beyond vision. The present study compared the effect of an integrative lighting system, providing low-intensity melanopic illuminance with the effect of an ordinary, qualitatively equivalent, electric lighting system. The study utilised a 2 × 7 randomised mixed experimental design. The sample consisted of 13 women and 11 men. Salivary melatonin secretion and subjectively perceived sleepiness in the evening were measured every half hour during 3 hours of light exposure. The chronobiologic typology (stability and amplitude) and trait-like negative and positive affect were measured once and analysed as covariates. The results showed a general increasing linear effect for both melatonin and sleepiness. A significant nonlinear effect of time was present in the group exposed to integrative lighting, indicating delayed melatonin secretion. The findings were stable across all levels of the examined covariates. These results confirm that the integrative lighting system produces effects beyond vision under otherwise ordinary lighting conditions. Furthermore, the results corroborate research suggesting that melatonin secretion and sleepiness may not be directly linked. The integrative lighting system provides new opportunities to develop indoor electric lighting resembling daylight. [ABSTRACT FROM AUTHOR]

There has been an increasing awareness in recent years about the evaluation of daylight and glare quality in buildings. In the study, an office space with a flat and a dynamic shading system facade (triangular cell facade) is discussed in the province of Mardin, which is in a hot and arid climate zone. Observing two different facade types in a single office space allows the study to be carried out in detail, and their suitability can be checked by producing quick design alternatives. The analysis and evaluation of daylight and glare quality over office spaces with two different facade types aims to develop an innovative approach. This objective is designed to respond to climatic conditions and contribute to the development of climate-sensitive designs. The study was parametrically simulated with the Grasshopper plugin and daylight plugin ClimateStudio tools in Rhino, an office space with both a flat facade and a dynamic shading system facade located in a hot-arid climate. As a result of the analysis, the dynamic shading system, which can transform according to the position of the sun, shows outputs in accordance with the LEEDv4 standard, minimizing the ASE value of the facade's annual sunlight exposure by up to 10%, while maximizing the spatial daylight autonomy sDA value by 60% or more. In addition, Daylight Glare Probability (DGP) values of 0.38 keep the visual quality affective. As a result, the office space with a dynamic shading system facade showed that it can significantly improve the flexibility of shading to control daylight measurements and glare, achieving the maximum level of visual comfort based on the LEEDv4 certificate. [ABSTRACT FROM AUTHOR]

The aim of this research was to evaluate how the quality interior design aspects of the staff office spaces at the Girls' College of Science and Arts, King Khalid University, Saudi Arabia, affect their happiness, comfort and performance of their duties, and also proposes a solution based on the sciences of the relationship between happiness and interior design. The aim was achieved by carrying out a survey on staff of the college. The participants were selected using a combination of probabilistic and random sampling. The research found that a good number of staff at the college are not happy with their work environments. Further analysis indicated that interior design deficiency is a major cause of unhappiness of staff at the college. The results showed that this may be attributed to three important aspects of quality interior space furniture: insufficiency of furniture and other workspace items; lack of aesthetics, functionality, comfort, color and materials (low quality materials) of furniture and other workspace items; and a lack of sufficient natural lighting being another major issue affecting the quality of natural and artificial lighting in some offices at the college. Participants were also not comfortable with some materials used in the interior space. The study recommends that office spaces should be redesigned to meet the following interior design criteria: appropriateness for the workplace (size, lighting and materials); color and decorations (non-dark colors); and appropriate accessories and tools of work. [ABSTRACT FROM AUTHOR]

Recognizing the growing importance of optimizing work environments for better cognitive performance, this study examined the relationships between general office lighting, psychophysiological responses and cognitive performance. Sixteen healthy adults in their 20s participated in experiments under nine different lighting conditions combining three levels of correlated color temperature (i.e., 4,000K, 5,000K, and 6,500K) and three levels of illuminance (i.e., 200 lx, 500 lx, and 800 lx). In the experiments, subjects' primary and complex cognitive performances were measured and their psychophysiological responses such as mental workload, drowsiness, mental fatigue and stress, and visual fatigue were evaluated. Statistical analyses revealed that higher correlated color temperature and illuminance significantly enhanced primary cognitive performance but did not significantly impact complex cognitive performance or most psychophysiological responses. Notably, psychophysiological responses and cognitive performances were found to have mutual relationships rather than one being an absolute independent variable for another. The study suggests that tailored smart lighting systems could enhance cognitive performance in office environments by dynamically adjusting lighting conditions based on real-time psychophysiological feedback. • Cooler and brighter lighting improve primary cognitive performance. • Visual fatigue and mental workload significantly affect creativity. • Psychophysiological responses and cognitive performance impact each other. • Mixed linear models and multiple regression analysis were used. • Psychophysiological responses should be considered for future lighting systems. [ABSTRACT FROM AUTHOR]

The experiment was targeted to develop design strategies and methods by testing the complex interplay between the dynamics of daylight and electrical lighting in an office. The double dynamic lighting design concept is based on the idea of adding task lighting, with a directionality referring to the daylight inflow and a variation on direct/diffuse lighting and respective changes in colour temperature respond to sky conditions and daylight levels. The experiment was conducted in an office space at Aalborg University in Copenhagen from September to December 2019. Four participants moved in and worked in the office with four-week periods of respective standard static lighting as a baseline, and dynamic lighting. In a parallel mixed method approach with interviews and questionnaires, the dynamic lighting was compared to the baseline and to a control group. The results indicate that the dynamic lighting periods had a positive effect on visual comfort, perceived atmosphere and work engagement. The studies helped to develop the definition of five dynamic light settings. Seasonal changes, time of day, dynamic sunscreens and individual needs for task lighting can be implemented in future field experiments as additional dynamic parameters to meet individual needs and circadian potentials for double dynamic light. [ABSTRACT FROM AUTHOR]

For an existing building from 19th century an architectural concept for revivalism and reorganization into a modern office building was made. For this purpose, a daylight system was implemented that roofs the inner courtyard and at the same time makes it the central place of representation and communication. In addition to the spatial function, the inner courtyard serves as a thermal buffer room and additional value can be achieved by using thin glass and its material properties. The free‐form geometry benefits from the increased stiffness due to the curved shape, which is regulated by the radii of curvature depending on the material thickness. The curvature has a direct influence on the reflection behaviour, which influences the light transport of natural light into the interior of the room and thus enables a reduction in electrical lighting for the office space. [ABSTRACT FROM AUTHOR]

Im Rahmen der Masterarbeit, die in Zusammenarbeit mit dem Josef Ressel Zentrum für Dünnglastechnologie für Anwendungen im Bauwesen entstand, wurde ein Bestandsobjekt aus dem 19. Jahrhundert revitalisiert und zu einem modernen Bürogebäude umfunktioniert. Dazu wurde ein Tageslichtleitsystem implementiert, das den Innenhof überdacht und gleichzeitig diesen zum zentralen Repräsentations‐ und Kommunikationsort macht. Neben der räumlichen Funktion dient der Innenhof als thermischer Pufferraum und darüber hinaus kann durch die Verwendung von Dünnglas und dessen Materialeigenschaften ein zusätzlicher Mehrwert erzielt werden. Die frei geformte Geometrie profitiert von der erhöhten Steifigkeit durch die gekrümmte Form, die abhängig von der Materialdicke durch die Krümmungsradien reglementiert ist. Die Krümmung übt einen direkten Einfluss auf das Reflexionsverhalten aus, das den Lichttransport von natürlichem Licht ins Rauminnere beeinflusst und somit eine Verminderung der elektrischen Beleuchtung für die Büroräume ermöglicht. N46 – daylight control made of thin glass. As part of the master's thesis, which was created in cooperation with the Josef Ressel Center for Thin Glass Technology for Structural Glass, an existing building from the 19th century was revitalized and converted into a modern office building. For this purpose, a daylight system was implemented that roofs the inner courtyard and at the same time makes it the central place of representation and communication. In addition to the spatial function, the inner courtyard serves as a thermal buffer room and additional value can be achieved by using thin glass and its material properties. The free‐form geometry benefits from the increased stiffness due to the curved shape, which is regulated by the radii of curvature depending on the material thickness. The curvature has a direct influence on the reflection behavior, which influences the light transport of natural light into the interior of the room and thus enables a reduction in electrical lighting for the office space. [ABSTRACT FROM AUTHOR]

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In this study, two experiments were conducted to investigate the effects of the color rendering index (CRI) and correlated color temperature (CCT) of light-emitting diode (LED) lighting on office user acceptance and to explore the proper color attributes for human-centric office lighting. Experiment 1 had four LED lights, with two levels for the CRI (CRI < 80: 79, 76; or CRI ≥ 80: 83, 84) and CCT (3000 K or 6500 K) at 300 lux. In experiment 2, there were four LED lights, with several levels for the CRI (CRI < 80: 78; or CRI ≥ 80: 87, 83) and CCT (3000 K or 6500 K) at 500 lux. Ninety-six participants in experiment 1 and ninety-four participants in experiment 2 performed a reading task. The results in experiment 1 and experiment 2 showed that LEDs with lower CRI values at warm color temperatures were rated as more acceptable than LEDs with higher CRI values at warm color temperatures. However, the positive effect extended to LEDs with higher CRI values at cool temperatures but not to LEDs with lower CRI values at cool temperatures. Therefore, the findings are that LEDs with lower CRI values at warm color temperatures and LEDs with higher CRI values at cool temperatures provide the right level of color attributes for office lighting. [ABSTRACT FROM AUTHOR]

Featured Application: Methodology proposed can be implemented in an app to obtain objective and accurate face illuminance measures required to investigate the effect of illumination on myopia progression. Introduction: To uncover a relationship between light exposure and myopia is complicated because of the challenging nature of measuring visually relevant illumination experienced by children. Objective: To find a methodology to measure face illuminance using a mobile device. Methods: Accuracy and precision of the mobile device's built-in ambient light sensor were tested under three different lighting conditions: full-field, a single small light, and one mimicking typical office illumination. Face illuminance was computed in six faces with different skin reflectances using pixel values in face images captured by the device camera placed at 30 cm in front of the face. The results were compared with those obtained with a commercial light meter situated at the face. Results: The illuminance measured by the device's ambient light sensor showed high linearity (R2 > 0.99) slightly under-estimating or conversely over-estimating face illuminance with full-field or single light sources but accurate for office lighting. Face illuminance measured by the devices' camera under indoor conditions using the new methodology showed a mean relative error of 27% and a high linearity (R2 > 0.94). Conclusions: Introduction of an app can be used to assess the association between visually relevant environmental light levels and myopia progression. [ABSTRACT FROM AUTHOR]

Featured Application: In-field spatially resolved light measurements for the characterization of non-visual effects and proper prediction of the circadian effectiveness for human-centric lighting design. As one factor among others, circadian effectiveness depends on the spatial light distribution of the prevalent lighting conditions. In a typical office context focusing on computer work, the light that is experienced by the office workers is usually composed of a direct component emitted by the room luminaires and the computer monitors as well as by an indirect component reflected from the walls, surfaces, and ceiling. Due to this multi-directional light pattern, spatially resolved light measurements are required for an adequate prediction of non-visual light-induced effects. In this work, we therefore propose a novel methodological framework for spatially resolved light measurements that allows for an estimate of the circadian effectiveness of a lighting situation for variable field of view (FOV) definitions. Results of exemplary in-field office light measurements are reported and compared to those obtained from standard spectral radiometry to validate the accuracy of the proposed approach. The corresponding relative error is found to be of the order of 3–6%, which denotes an acceptable range for most practical applications. In addition, the impact of different FOVs as well as non-zero measurement angles will be investigated. [ABSTRACT FROM AUTHOR]

The article discusses the benefits of replacing office lights with LED bulbs in dental clinics to improve energy efficiency and reduce overhead costs. The Independent Electricity System Operator (IESO) offers a free retrofit program under its Save on Energy program, providing eligible small business owners with up to $3,000 in lighting fixtures. The program aims to help businesses use electricity more efficiently and manage the province's power grid. Interested practice owners can contact the IESO for more information and to determine if they qualify for the incentives. [Extracted from the article]

Due to the very limited information available during building design phase, lighting automation systems tend to follow pre-defined control curves and use normative default values. However, these are unlikely to reflect the wide variation in daily working hours and individual lighting preferences. Inadequate user modelling can result in missed energy and comfort targets, as well as insufficient light doses. Given that the building sector accounts for around one third of the world's energy demand, and lighting is one of the main consumers, a higher level of user representation in lighting control systems is essential to meet climate and environmental targets. The general practical applicability of user-centred concepts usually fails due to implementation, inadequate mapping of objectives to required parameters, availability of information and mapping in control systems. This comprehensive literature review of 160 articles evaluates the potential of individual control concepts in relation to the target criteria of lighting systems and identifies the necessary technical system components for greater applicability. The focus of the review is on daylight and artificial lighting and their application in office environments. From the results obtained, key elements for better implementation of user-centred concepts in lighting control were derived. These include zoned lighting, human-in-the-loop approaches, and sensor fusion. Post-occupancy evaluation, supported by social science methods, can help to capture relevant physiological and psychological parameters. The review concludes that post-occupancy optimisation of user-centred lighting applications offers great potential for overcoming previous design limitations and subsequently reducing performance gaps. • A bibliometric and manual evaluation of 123 research articles. • Technologies for detecting relevant user variables on KPIs are highlighted. • Tabular comparison of user-centred lighting concepts in the context of KPIs. • Zoning, post-occupancy evaluation and reinforcement learning are key technologies. [ABSTRACT FROM AUTHOR]

In order to solve the problem of lighting waste in developing countries and backward areas, an application of Internet of Things technology, combined with edge computing, is proposed to achieve intelligent lighting system for office buildings. The system takes the Internet of Things technology as the core, and combine ZigBee short-distance, low complexity, low-rate, low-power, low-cost and two-way wireless communication advantage, and based on mesh topology designs an energy-saving system for office building lighting. Intelligently control the switch of the luminaire or switch the preset illumination mode according to the sensed number of people in the current office, location and illumination brightness, effectively overcomes the defects of traditional lighting mode management backwardness, waste of energy, poor comfort and complicated wiring. The objective is to achieve the goal of energy saving and consumption reduction for office building lighting. Through practice and experimental test analysis, the improved energy consumption of the energy saving is about 30% per year, and the effect is remarkable.

In order to solve the problem of lighting waste in developing countries and backward areas, an application of Internet of Things technology, combined with edge computing, is proposed to achieve intelligent lighting system for office buildings. The system takes the Internet of Things technology as the core, and combine ZigBee short-distance, low complexity, low-rate, low-power, low-cost and two-way wireless communication advantage, and based on mesh topology designs an energy-saving system for office building lighting. Intelligently control the switch of the luminaire or switch the preset illumination mode according to the sensed number of people in the current office, location and illumination brightness, effectively overcomes the defects of traditional lighting mode management backwardness, waste of energy, poor comfort and complicated wiring. The objective is to achieve the goal of energy saving and consumption reduction for office building lighting. Through practice and experimental test analysis, the improved energy consumption of the energy saving is about 30% per year, and the effect is remarkable. [ABSTRACT FROM AUTHOR]

In view of the current problems of energy waste in China's office lighting, lack of intelligent lighting control and single adjustment mode, based on the domestic intelligent control system, development status, current stage technology, etc., this paper proposes to adopt arduino as the main controller, combine with the infrared inductive sensor and the light sensor, the wifi network is used as the communication mode, and the delay, turn-off control and dimming functions can be automatically realized according to the detection condition of the sensor, thereby realizing the detection of the office lighting environment and the control and adjustment of the office lighting fixture. The purpose of this system is that it has the characteristics of low cost and low carbon green, which is very suitable for office environment. [ABSTRACT FROM AUTHOR]

Sensor-triggered control strategies can limit the energy consumption of lighting by considering the presence of users in the office and dimming lighting down when it is not needed. In multi-user offices, the application of occupancy-based dimming at room level limits the energy saving potential. However, zone- or desk-based dimming may affect the comfort of co-workers due to its dynamics. This paper reports the assessment by 17 participants (30–50 years of age) of occupancy-based dimming in a mock-up office, using different dimming speeds. Participants consisted of co-workers experiencing changes triggered by others, and actors triggering these light changes. While the participants performed an office-based task, the luminaire above the actors' desk was dimmed from approximately 550 lx to 350 lx (average horizontal illuminance), and vice versa. The participants evaluated the dimming conditions regarding their noticeability and acceptability. The study showed that the noticeability of light changes due to dimming, increases when fading times become shorter. Dimming with a fading time of at least two seconds was experienced as acceptable by more than 70% of the participants. The results of this experiment provide insights to system behaviour that does not compromise user experience while addressing energy efficient use of electric lighting. [ABSTRACT FROM AUTHOR]

Light shelf applications are one of the improved daylight system, help to contribute energy saving by using daylight effective. Latitude is an important parameter that affects the placement and efficiency of light shelf. The placement and efficiency of light shelf on 30°&45° latitudes that includes Turkey is investigated for a typical Office unit with different office heights in this study. Ecotect and Radiance software is used in calculations. Consequently, it is determined that the usage of interior positioned light shelf is suitable and the efficiency of light shelf increases with office height within determined conditions on 30° and 45° latitudes. [ABSTRACT FROM AUTHOR]