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This paper conducts a comprehensive analysis of the light environment in different areas of residential houses located in Beijing's Guangyuanli neighborhood. The main objective of this study is to assess the contribution of natural daylight to residential illuminance, with the aim of providing a foundation for reducing energy consumption and enhancing light comfort. While previous research predominantly focused on sensor deployment in single scenes such as offices and classrooms, these approaches are inadequate for multi-scene analysis of daylight in residential areas. Moreover, traditional deployment methods can negatively impact the quality of life and everyday living experience. To overcome these limitations, a prediction model is developed to estimate ceiling and window illuminance, as well as work surface illuminance in various scenes within residential buildings. The Dialux software is employed for data simulation, and a GA-optimized BP neural network is utilized to train the model, establishing the mapping relationship between input variables and corresponding illuminance outputs. By inputting sensor values from different scenarios into the model, the predicted daylight illuminance values can be obtained. This predictive approach facilitates the evaluation of light comfort and energy consumption reduction in different functional areas of residential buildings. [ABSTRACT FROM AUTHOR]

Taking the high and large space of the University of Science and Technology Beijing Gymnasium as this research object, this paper analyzes the influence of different window positions, window-to-wall ratio (WWR), solar heat gain coefficient (SHGC), heat transfer coefficient (K), and visible light transmittance (VT) on the total indoor energy consumption in winter and summer and obtains the relationship between the daylight factor and VT formed when the window is opened per unit area. Through energy consumption simulation, the variation law and calculation formula for indoor total energy consumption are obtained. The results show that the SHGC and K of the exterior window have a significant influence on the total energy consumption. By using the energy consumption simulation of different types of exterior windows, it is concluded that the SHGC of the south-facing window is negatively correlated with the variation of air conditioning energy consumption per unit area Δe1,w, while the others are positively correlated. Moreover, the SHGC and K of the skylight have the most significant influence on the Δe1,w. The total energy consumption decreases and then increases with the increase in the window area, and there is a lowest point, so the right side of the lowest point is less than or equal to 105% of the lowest total energy consumption as a reasonable window area zone. Finally, a progressive optimization method for weighing daylighting and energy consumption in university gymnasiums in Beijing is proposed. [ABSTRACT FROM AUTHOR]

Thermochromic (TC) window has been developed as an effective approach to realize building energy saving by regulating solar transmittance according to temperature stimuli; however, the non-uniform transmission and absorption of the solar spectrum result in a significant color shift and temperature increase. This study investigates the radiometric, photometric and colorimetric performances of four different TC windows with an experiment-verified model. The simulation and calculation are conducted under measured spectrum conditions in Beijing; subsequently, a comprehensive evaluation method for daylight-thermal environment method is conducted. The results show that all selected TC windows possess an energy efficiency between 3.0% and 7.9%, improve daylight availability from 2.8% to 18.8%, and reduce discomfort hours by up to 111 h. Two hydrogel TC windows improve the quality of dynamic transmitted daylight by nearly 7% considering correlated color temperature and color rendering index; the HETS hydrogel TC window is found to be the most suitable for Beijing. Finally, to increase the application potential of TC windows in Beijing, several material properties are desired, including high transition temperature with high solar modulation capability, high and uniform visible light transmittance, and low emissivity. This process for the optimization of climate-responsive material can be further adopted in other areas. • Four different thermochromic windows are compared for the Beijing climate. • The annual dynamic spectrum of Beijing is measured and adopted as a boundary condition. • The model is verified by experiments based on measured meteorological conditions. • Comprehensive evaluation, including radio, photo, and color aspects, is conducted. • Constructive suggestions on regionally suitable window characteristics are given. [ABSTRACT FROM AUTHOR]

Electrochromic (EC) glazing provides a promising solution to actively adjusting the sunlight and radiant heat through windows in response to building visual and thermal environmental requirements, and control strategies play a critical role in the application of EC technology in buildings. However, there is a conflict between the visual and thermal environmental requirements for EC regulation during a cooling season. To solve this problem, this paper developed a predictive control strategy for EC glazing. It was achieved based on two theoretical models which could predict the energy performance of EC glazing at different tint states, including the solar radiation heat transmitted through the glazing and lighting energy consumption. The optimum glazing state was determined based on real-time minimized energy consumption. Study results showed that the predictive control strategy outperformed the rule-based control strategy, with percentage energy saving of an office room in Beijing, China from 8.04% to 12.78% over an entire cooling season. In addition, the paper evaluated the energy-saving of using EC glazing under the predictive control strategy in 28 Chinese cities. The results indicated that EC glazing was highly applicable in most of cities with energy saving from 2.35 kWh/m2 to 5.04 kWh/m2 over an entire cooling season. • A predictive control strategy for EC glazing was developed. • Theoretical models were established to predict the EC glazing energy performances. • Real-time minimized energy consumption determined the optimum EC glazing state. • Balance between the visual and thermal environment requirements was achieved. • The energy-savings of using EC glazing in 28 Chinese cities were assessed. [ABSTRACT FROM AUTHOR]

There is a tendency toward larger transparent envelopes in architectural design, which could causes excessive energy consumption and visual discomfort. Using advanced shading systems with control strategies could potentially improve the indoor environmental quality and reduce the building energy consumption. In this research, daylight and thermal performances of a double-skin facade (DSF) system with multisectional shading devices using combinations of roller shades and blinds along with different control strategies were investigated under three representative climatic conditions of China. The performance of DSF systems with and without shading devices were comparatively analyzed by evaluating the annual heating, cooling, and artificial lighting energy consumption, daylight availability, and visual discomfort index using EnergyPlus and Radiance. The results indicated that the DSF with a multisectional shading system and proper control algorithms can save up to 6.8% and 4.8% for annual building energy consumption in Xiamen and Shanghai, respectively, but slightly increased by 2.4% in Beijing, when compared with the baseline without any shading device. For daylight performance, the multisectional shading system with proper control strategy shows a significant contribution to eliminating annual sunlight exposure (ASE) and discomfort glare while maintaining the daylight availability at a similar level compared to the system without shading. Meanwhile, the combination could improve spatial daylight autonomy (sDA) by 11.9%, 16.7%, and 19.1% in Xiamen, Shanghai, and Beijing, respectively, when compared with the individual shading system. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The artificial light sources in urban areas constitute the primary source of stable nighttime illumination, which can be utilized to reflect the nighttime human activity and the conditions of public space lighting. The previous studies have focused on the evaluation of lighting environments in specific scenarios and the public's perception of these lighting environments. There has been limited analysis of the characteristics of public space lighting and its influencing factors in detail across different urban functional areas. This study primarily utilizes high-resolution SDGSAT-1 glimmer imagery and data from field measurements of lighting attributes to analyze the characteristics of public space lighting and its influencing factors in various urban functional areas. Furthermore, it establishes a quantitative relationship between measured illuminance and glimmer imagery to assess public space lighting levels. The results show that: (1) Various urban functional areas exhibit different illuminance levels, but they all maintain good illuminance uniformity. Additionally, to reduce the impact of the blue light spectrum on public visual perception, urban public space lighting primarily utilizes warm color temperatures with low color rendering properties. However, nighttime public space lighting cannot always achieve a balance between public comfort and high color rendering; (2) In the main urban area of Beijing, 98.5% of illuminance values fall within the range of 0 to 35 lx, indicating that most areas have good public lighting conditions. However, cases of over-illumination are also observed; (3) The building height has a positive correlation with public space lighting, while vegetation density exhibits a negative correlation. This study explored the characteristics of public space lighting in different urban functional areas and conducted a large-scale analysis of urban public lighting conditions using high-resolution nighttime images, providing evidence for the design and optimization of public space lighting in cities and better serving urban sustainable development, and contributing to the achievement of UN Sustainable Development Goal 11.7: By 2030, provide universal access to safe, inclusive, accessible, green and sustainable public spaces, particularly for women, children, older persons and persons with disabilities. • Detailed analysis of lighting characteristics using field-measured data. • Realize large-scale analysis of urban nighttime lighting levels and distribution. • Most public lighting is concentrated in urban roadways and commercial districts. • Influencing factors have different impacts on different urban functional areas. [ABSTRACT FROM AUTHOR]

• Two representative thermochromic windows for NIR and visible transmittance control respectively were selected. • Comprehensive analyses for the selected thermochromic windows were conducted at three different climates. • Both energy efficient and indoor luminance environmental can be improved with the use of NIR and VIS control thermochromic windows. • Building energy saving over 50% can be achieved with the proper TC applied compared with traditional double glazing. Thermochromic (TC) windows are able to adjust solar radiation transmitted into buildings in response to varying window surface temperature. Vanadium Dioxide (VO 2) is the most common TC material used for TC windows, as it can reduce near infrared (NIR) solar transmittance to attenuate undesirable solar heat gains during hot days when window surface temperature rises above a particular transition temperature. However, there have been few studies of the effect of TC windows on the indoor luminous environment. In order to improve daylight control, an innovative Iron-liquid based TC window film, which can control the visible (VIS) spectrum was introduced and applied alongside a VO 2 based TC material in this study. The combined performance of these two types of TC material was evaluated under three climatic conditions within China: Beijing, Shanghai and Guangzhou. The results show that increasing either the NIR or visible transmittance difference after switching, is beneficial for thermochromic performance, the maximum energy saving increasing from 11% to 18%, and UDI 500–2000 lx increasing by up to 27%. Combined application of NIR and visible spectral selection results in improved balance between energy demand and daylight provision. It was found that the energy saving potential and daylighting regulating capability offered by the combined implementation is highly dependent on matching the climate conditions to the TC windows. [ABSTRACT FROM AUTHOR]

This article presents a pilot study of effects of glazing on participants' satisfaction and performance in a full-scale office in Beijing, China. Five glazing systems were tested during a heating season (17 November 2016 to 11 January 2017). Research methods include lighting measurements, subjective assessments, and reaction time test (GO/NOGO). Key findings are given as follows: Daylight illuminances associated with glazing types and times of day play a major role of influencing participants' visual performances, alertness, physical wellbeing, and relaxation. The glazing type and CCT of daylight did not significantly affect visual responses if a proper daylight illuminance can be achieved. Circadian Stimulus (CS) under daylighting varies in times of day and glazing types, which would affect participants' alertness and relaxation. Under varying daylight illuminances, some glazing types that can deliver a higher CCT of light would improve participants' physical comfort and give rise to a longer reaction time. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive approach to renovating and optimizing balconies in old residential buildings in Beijing. Firstly, it explores residential balconies' evolution, characteristics, and development trends to identify various sample types and understand the associated problems and residents' needs related to balconies through investigation. Secondly, the Rhino/Grasshopper parametric platform is employed to simulate the performance and analyze data from standard balcony types, resulting in five qualitative and four quantitative renovation strategies and methods. Subsequently, these comprehensive renovation and optimization design strategies are implemented in the renovation process, and their performance is simulated. The daylight autonomy (DA), universal daylight indicator (UDI), and spatial daylight autonomy (sDA) metrics experienced significant increases of 16.56, 20.12, and 0.13, respectively, indicating improved light environment and functionality. Notably, the proposed strategies maintain consistent energy consumption and thermal comfort levels. Both PMV and PPD have improved, but the improvement is not significant, only by 0.01. The window-to-wall ratio has been increased by 0.1, and insulation has been added. The overall thermal comfort value is stable. These findings validate the practicality and effectiveness of the proposed approach and methods. This study provides valuable references for renovating and optimizing balconies in old residential buildings, contributing to problem-solving efforts and enhancing living quality. [ABSTRACT FROM AUTHOR]

• The influence of skylight-to-roof ratios(SRRs)and skylight distribution of SIPVs on indoor daylighting quality of railway station represented large space buildings was investigated. • The most recommended value ranges of SRRs for both centralized and uniserial array distributed SIPVs has been proposed. • The SRRs based design strategies for both SIPV distributions has been concluded for Lhasa and Beijing represented solar radiation and lighting climates in China. Photovoltaic Integrated Skylights (SIPVs) have been widely used due to their unique synergistic benefits of shading and power generation. Their variable shading and light transmission properties upon varying lighting climates could aggravate the complexity of the daylighting conditions, especially when applied to large space public building skylights. In this study, Chinese cities Lhasa and Beijing were selected as representative cities for semi-transparent photovoltaic (STPV) skylight surveys corresponding to high and moderate solar radiation levels. Railway station waiting halls as the typical large space building, together with SIPVs in varying distribution modes and skylight-to-roof ratios (SRRs) have been modeled and examined. By the aid of dynamic daylighting indicator metrics and DAYSIM simulation tool, this work verified critical roles that SIPV SRRs play in indoor daylighting qualities, for both centralized and uniserial array skylight distributions. As a result, 30 % ∼ 35 % and 23 % ∼ 30 % were determined as the best value ranges for centralized SIPVs, while 16.52 % ∼ 19.27 % and 11.01 % ∼ 19.27 % were confirmed as the best value range for uniserial array distributed SIPVs, for Beijing and Lhasa accordingly. For the first time SIPV SRR based design recommendations considering both typical distribution modes had been concluded for railway station represented large space buildings, for Lhasa and Beijing represented daylighting climates or similarities. The research outcomes can assist more effective SIPV designs and daylight optimizations for such large space type public buildings. [ABSTRACT FROM AUTHOR]

• A solar fiber lighting and photovoltaic power generation system was developed. • A spectral beam splitter was used to separate the solar radiation in different wavelengths. • The designed system was theoretically simulated and experimentally tested. • The effects of structural parameters on the performances of the system were examined. • The lighting effects and overall average efficiency were examined. Modern buildings tend to be high-rise and dense, and indoor lightings are extensively depending on electricity even on sunny days currently. In addition, for those existing solar lighting technologies in development, only the visible light of solar radiation has been used, with the extra spectral energy dissipated by waste heat. A solar fiber optic lighting and photovoltaic power generation system based on spectral splitting technology (SSLP) is proposed and tested in this study. The sunlight is divided into different wave bands through a spectral beam splitter, where the visible light is used for optical fiber illumination, and the near-infrared radiation is used for photovoltaic power generation. The designed SSLP system is simulated with the Monte Carlo ray tracing method, and then experimentally tested. The effects of structural parameters and tracking accuracy on the optical performances of the system are examined. The experimental results show that the sunlight transmitted to the room using optical fiber is bright and comfortable, with an average lighting efficiency of 15.1 %; meanwhile, the average power generation efficiency of the system is about 6.1 %, reaching one-third of the value of conventional PV modules. When the output luminous flux is converted by the luminous efficiency of fluorescent lamps, the overall average efficiency of the system can reach to 29.5 %; when converted by LED lamps, the overall average efficiency can reach to 25.4 %, which are both more efficient than the conventional PV power generation. Taking the solar radiation conditions in Beijing as an example, when the sunlight collection area of the system is 1 m2, it can provide 8 h of sunlight illumination of 500 lx per day for a room of 19.7 m2, while the daily generated electricity can be provided to the LED lamps to extend the lighting time by 2.5 h. [ABSTRACT FROM AUTHOR]

Lighting is necessary for all kinds of buildings and consumes a large amount of electricity. Tubular daylighting devices (TDDs) can serve as an alternative, but they may also have thermal effects on the indoor environment, which has not been studied yet. In this paper, a lighting-heating coupled TDDs system was designed and built, to improve the use of TDDs for building energy savings and sustainability, where antimony tin oxide (ATO) nanofluids were introduced to absorb extra unexpected heat and then supply domestic hot water. Meanwhile, a new method was developed to calculate the annual amount of energy output of TDDs under different mass concentrations of ATO nanofluids. Results showed that the ATO nanofluids of 100 ppm can absorb ∼ 50% solar radiation coming along with more efficient visible lighting. Furthermore, in the case study in Beijing, TDDs with 100 ppm ATO nanofluids could generate over 10 tons of domestic hot water while saving 30.9 kWh of electricity for refrigeration, resulting in a ∼ 10% improvement on total energy-saving performance. This research work demonstrates the high potential of using the designed lighting-heating coupled TDDs system in buildings for both energy savings and daylighting benefits. [ABSTRACT FROM AUTHOR]

The large-scale use of curtain walls in stadiums and other public buildings will cause glare and increase the burden of energy consumption, especially in summer. In the early stage of the design, the optimization of the shading devices directly affects the decision-making of the building facade. This research proposes a multi-objective facade optimization method (MOO) for stadium design, using image density atlas (IDA) to provide decision-making basis for facade shading ratio (FSR) optimization in the preliminary design process of gymnasium. In contrast to the traditional design method, the optimized design framework proposed in this study will achieve the balance optimization among contradictory goals of daylight comfort and solar radiation at the same time to optimize the daylighting performance while avoiding glare and reducing energy burden. In this study, a gymnasium in Xiong'an, Beijing was selected as the test case. Researchers took the hourly average illuminance, hourly average solar radiation accumulation, and glare index during the opening hours of the gymnasium in summer (August) as the optimization goals. Then, the genetic algorithm SPEA-2 was used to explore the Pareto frontier solution set of FSR. The optimization scheme FSR = 0.37 is formed through comparison and screening. The research results achieved a 38.5% reduction in DGP, a 54% reduction in solar radiation, and control of illuminance loss within the acceptable range. The case study reveals the importance of FSR optimization to the indoor daylight environment of gymnasium in summer, and how parameter changes affect the rules of various metrics. • Method of multi-objective optimization (MOO) for gymnasium facade is proposed. • Relationship among FSR and daylight illuminance, DGP, and radiation is investigated. • 23 Pareto Frontier of FSR is explored by SPEA-Ⅱ. • Optimization achieved a 38.5% reduction in DGP and 54% reduction in solar radiation. [ABSTRACT FROM AUTHOR]

Awakening lighting has an important influence on circadian rhythm, alertness, mood and other physiological and psychological indexes. In a real situation with no electric awakening light, psychological suggestion or interference, the influencing mechanism of awakening daylight on human physiology and psychology is explored from the awakening data of dynamic daylight. This data can further guide the application of electric awakening lighting. The effects of daylight exposure at eye level on sleep quality, morning alertness, mood and fatigue of college students in dormitories in Beijing were studied. The subjects were 8 male and 8 female students from 4 dormitories in two adjacent apartments, and field experiments were conducted for 36 days in winter and 30 days in summer. The real-time illuminance of daylight before awakening was recorded by a wireless illuminance sensor, and the amount of light exposure and the maximum illuminance before awakening were calculated. The evaluation data of physiological and psychological indexes such as sleep quality, morning alertness, mood and fatigue were obtained by using sleep monitoring equipment—Jawbone UP3, PSQI, KSS, positive and negative semantic scales. The results showed that the lighting exposure accumulation before awakening in summer were significantly correlated with morning alertness, mood and deep sleep duration and there was a significant correlation between the E max and morning alertness in summer. In addition, there were significant differences in deep sleep duration and morning alertness between different groups of lighting exposure accumulation in summer. There was no significant correlation between the lighting exposure accumulation or max value of illuminance and the physiological and psychological indexes in winter. • A field study on the effects of awakening daylight on morning alertness, mood, fatigue and sleep quality of college students. • There may be a threshold for the LEA of awakening daylight effect. • Provides a new reference case for electric awakening lighting. [ABSTRACT FROM AUTHOR]

To improve the activity spaces and bedrooms in a nursing home for older adults in Beijing, the satisfaction of these individuals regarding an interior daylight environment was investigated through questionnaire surveys and illuminance measurements. A geometric model was then created according to the nursing home's building layout, and the Integrated Environmental Solutions < Virtual Environment> (IES ) program was used to simulate an entire year of the interior daylight environment of these spaces. The validity of the simulation was verified with the measured values. The daylight environment for the entire year was analyzed based on simulation results that used both existing standards and the four-level criteria obtained from an on-site investigation. The results imply that older people's demand for sunlight might be determined not only by their visual requirements but also by psychological or physiological nonvisual requirements. Older individuals could even tolerate certain daylight glare environments due to their eagerness for sunshine. In different functional spaces, older adults have different expectations for sunlight illuminance. • Older residents' sensations regarding daylight environments were investigated. • A four-level daylight satisfaction scale for older individuals was defined. • The daylight illuminance of an elderly nursing home was simulated and evaluated. • Psychological expectations affect older people's sensation of daylight environments. • Skylights improve older people's satisfaction levels in an activity room. [ABSTRACT FROM AUTHOR]

This study presents an investigation of circadian lighting potential for a fibre optics daylighting system (FODS) in a single office in Beijing, China. Research methods included the monitoring of FODS daylighting performance during a 11-month period, the indoor lighting simulations at the horizontal workplane and vertical planes using a single office model, and thus the theoretical calculations of circadian stimulus brought by the FODS. Key findings are as follows: There is a high possibility that a proper level of circadian light at a windowless workspace could be achieved through applying the FODS in northern China. With this FODS, the non-visual effect of lighting (circadian system entrainment) can be attained when a standard lighting requirement was met at the horizontal workplane based on occupants' visual performance in this office. Compared with typical artificial lighting systems, the FODS can deliver circadian light in a more efficient way. In addition, it can be found that the application of FODS system would benefit office workers in terms of both visual and non-visual aspects. It is the first study to investigate the non-visual performance of a fibre optics daylighting system. • Investigation of Circadian Light potential of FODS in a single office in Beijing. • A 11-month monitoring of FODS in terms of daylighting performance in a lab. • Analysis of computational simulation and theoretical calculation for Circadian Stimulus. • Identification of a high potential of the FODS to achieve circadian entrainment. [ABSTRACT FROM AUTHOR]

A dormitory is one of the most important places for college students at a university. The daylight of a dormitory has an important impact on students' work efficiency, mood, and sleep quality. To explore the influence of daylight exposure on morning alertness, mood, and sleep quality before waking up, a study was conducted based on the hourly dynamic meteorological parameters of Beijing to simulate the daylight exposure at eye level of students on different beds on the sixth floor of the No. 11 apartments at Tsinghua University. The data for sleep quality, morning alertness, and mood were collected by a subjective questionnaire in November and December in 2017 for 88 male students in 28 dormitories and in May and June for 90 male students in 36 dormitories. The results showed that the positive correlation between the eye light exposure before waking up and the quality of sleep and morning alertness was significant. This study can provide a reference for the daylight design of dormitory spaces and the scientific arranging of beds and orientations; it can also provide a reference for a rotation system. • The study investigated the effects of awakening daylight on morning alertness, mood and sleep quality of male college students. • Presenting a method to calculate the daylight exposure at eye level before awakening. • Awakening daylight shows different effects in different seasons. • Provides some new references for daylight design of dormitory buildings. [ABSTRACT FROM AUTHOR]