In the tropical regions represented by Hainan,there are abundant solar and thermal resources,and it is relatively suitable for the construction of photovoltaic greenhouse(PVG).However,the construction of PVG still rel...In the tropical regions represented by Hainan,there are abundant solar and thermal resources,and it is relatively suitable for the construction of photovoltaic greenhouse(PVG).However,the construction of PVG still relies mainly on experience and is incapable of quantifying the balance between the photovoltaic(PV)generation and the light requirements for agricultural production.As a result,actual PVGs are primarily PV-based,without carefully considering the needs of agricultural daylighting.To quantify the influence of the design parameters of PVGs and the layout of PV panels on the internal daylighting of serrated PVGs,and to optimize the daylighting design of the roof,this paper utilizes the Design Builder software to establish gradient models for a multi-span serrated-type PVG in tropical regions.Gradient models were established in terms of aspects,namely span,width of longitudinal/transverse daylighting strip,height,roof angle,and photovoltaic panel coverage rate(PCR).Daylighting in the greenhouse of each gradient model was simulated,and with the annual average daily light integral(A_(DLI))and distribution uniformity(DU)as evaluation indicators,the influence of various design parameters on the daylighting inside the greenhouse was quantified.The result reveals that:(1)PCR is the decisive indicator for daylighting in the PVG,and a function between PCR and the A_(DLI) is derived as A_(DLI)=-15.5 PCR+16.841;(2)Increasing the width of longitudinal daylighting strip significantly improves the A_(DLI) and enhances DU while increasing the span has a noticeable effect on improving A_(DLI) but does not significantly enhance DU;(3)Increasing the eave height without changing PCR does not enhance A_(DLI) but effectively improves DU;increasing the transverse daylighting strip and adjusting the roof angle hardly improves A_(DLI).In summary,it is recommended that the optimal span for PVGs in tropical regions be set within the range of 6.5-8.0m,and the eave height be set within the range of 2.5-3.5m.Preferably,the longitudinal daylighting strip with a width ranging from 0.5-0.8m should be installed.Based on the above relationship function,the PCR can be calculated according to the appropriate light demand for the cultivated crops.The daylighting design theory proposed in this paper can provide a theoretical basis and reference for the healthy development of the PV industry in tropical regions.展开更多
This paper explains how the optimized classrooms were selected and the results that were achieved by the optimizations carried out and finalized.The context of the research is the city of Concepción,in Chile.Virt...This paper explains how the optimized classrooms were selected and the results that were achieved by the optimizations carried out and finalized.The context of the research is the city of Concepción,in Chile.Virtual models of classrooms were evaluated using the Radiance software.We used a methodology that allowed us to determine the luminous conditions under different types of skies,seasons of the year and times of the day.The evaluation of the typologies was performed based on three defined criteria,in order to achieve the stated design objectives.We defined the optimal solutions for each orientation and,finally,we stated design recommendations for daylit classrooms to ensure the visual comfort of the students.These recommendations link all that found in the initial analysis with that found in the optimization stage.展开更多
Daylight is a fundamental element to obtain built environments that promote environmental comfort and energy efficiency. However, strategies that enhance the building daylight performance can affect its thermal energe...Daylight is a fundamental element to obtain built environments that promote environmental comfort and energy efficiency. However, strategies that enhance the building daylight performance can affect its thermal energetic performance. In this sense, research that addresses these aspects at the same time is considered essential. The objective of this paper was to evaluate the daylighting and thermal-energetic performance of administrative environments in a public institution, and to propose strategies that will enhance the use of daylight and lower energy consumption. Therefore, for future projects, and considering new buildings, and retrofit, this research will be an important reference. The research was developed through a case study of an administrative building model, in which the characteristics of solar orientation, light shelf use, glass type, and light and dark colors in walls were modified and combined, deriving it into models proposed. The daylighting performance evaluations were performed through dynamic simulation with the Rhinoceros for Diva software, and the thermal-energetic performance evaluations with the EnergyPlus software. The results of the work showed that a suitable solar orientation has a great impact on the automation of daylight and the energy consumption of the evaluated models, followed by the type of glass and the use of the light colors in internal walls, and that the use of artificial lighting with dimerization is fundamental as a complement to the daylight autonomy. For the boundary conditions of the study, the use of light shelves modified neither the daylight performance nor the thermal-energetic performance of the evaluated models.展开更多
Daylighting studies in buildings are key parts of environmental analysis and can be easily conducted at the early stages of design as part of environmentally responsive building design as well as to inform the final a...Daylighting studies in buildings are key parts of environmental analysis and can be easily conducted at the early stages of design as part of environmentally responsive building design as well as to inform the final architectural layout and interior design. The main aim of this study is to demonstrate how such daylighting studies can be completed at the early stages of design and, at the same time, to show the impact of window design and positioning on building indoor environments. The paper is focused on a study of window influence on room daylighting in residential buildings and computer lighting simulations in software packages： Windows Daylighting System and Autodesk Ecotect Analysis, have been carried out for different style and positioning of windows using several case studies. The main findings clearly indicated that not only the window size and style matters, but also the positioning of windows considering external walls which would make a significant influence on room daylighting levels and, therefore, such daylight studies are very important for the early stage of environmental analysis during building design.展开更多
Improving daylighting strategy is a mandatory step to achieve visual enjoyment and energy saving in buildings. Psycho, physiological effects and energy performance have to be investigated in order to define a range of...Improving daylighting strategy is a mandatory step to achieve visual enjoyment and energy saving in buildings. Psycho, physiological effects and energy performance have to be investigated in order to define a range of different daylighting strategies, thanks to daylighting devices and climate based daylight modeling. Daylighting optimization ensures indoor healthier rooms, reduces electric light consumption and cuts the risk of glare. The best way to achieve these targets is to define users lighting needs, based on visual targets and to draw up some green measures to reduce electricity demands. Involving new climate-based daylight modeling metrics aims at defining proper illumination targets, in order to drastically reduce electrical lights, as well as reducing thermal loads deriving from cooling and HVAC （heating, ventilation and air conditioning） systems.展开更多
In order to meet the requirements of indoor illumination, a LED daylight lamp model was designed, it can replace traditional fluorescent lamp without insteading additional power supply establishment. The optical prope...In order to meet the requirements of indoor illumination, a LED daylight lamp model was designed, it can replace traditional fluorescent lamp without insteading additional power supply establishment. The optical properties of the model were simulated using optical analysis software. Its luminous efficiency is about 30.4 lm/W, and the illuminance is about 38 lux when the distance is 1.5 m between the center of the model and measured spot. With the theoretically-optimized design of LED model, experiments based on the results of the optimal simulation in the laboratory were conducted to verify the performance of the proposed LED model, it reaches a power factor of about 0.8 at 6 W. The simulation results are very similar with the measured values. It is testified that simulative method is one of the effective tools for LED lighting optical design.展开更多
The following article has been retracted due to the fact that it cannot be accepted as Duplicate Publication. The Editorial Board takes a very strong respect to the author’s situation on this matter. This paper publi...The following article has been retracted due to the fact that it cannot be accepted as Duplicate Publication. The Editorial Board takes a very strong respect to the author’s situation on this matter. This paper published in Journal of Power and Energy Engineering Vol.3 No.4, April 2015, has been removed from this site.展开更多
The transparent C-doped TiO2 nanostructure films were fabricated on the silicate glass substrates by sol-gel spin-coated method. The as-prepared films were characterized by X-ray diffraction （XRD）, scanning electron...The transparent C-doped TiO2 nanostructure films were fabricated on the silicate glass substrates by sol-gel spin-coated method. The as-prepared films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, UV-visible absorption spectra （UV-vis） and X-ray photoelectron spectroscopy （XPS）. The photocatalytic activity was evaluated via the photocatalytic oxidation of methylene blue in aqueous under daylight irradiation at room temperature. The results show that the daylight-induced photocatalytic activities of the as-prepared films are improved by the C-doping. The calcination temperatures significantly affect the morphology, microstructure and photocatalytic activity of the as-prepared samples. At 723 K, the C-doped TiO2 films exhibit the highest photocatalytic activity due to the synergetic effects of good crystallization, appropriate oxygen vacancies and strong absorption in the near UV and visible-light region.展开更多
Currently, daylighting ducts system is widely used as a daylighting device. Generally, daylighting duct system efficiently takes light from outside during the day, and conveys daylight to required location through lig...Currently, daylighting ducts system is widely used as a daylighting device. Generally, daylighting duct system efficiently takes light from outside during the day, and conveys daylight to required location through light duct manufactured by high reflectance mirror. Daylighting duct system can convey daylight to underground space that has no windows opening to external space. Daylighting system is composed of light collection part, light guide part and light emission part. Efficiency of daylighting system is depending on type of each part used in the system. However, it is very difficult to estimate exact light flow in the system considering type of the parts. Authors performed measurement experiments to make clear the light flow with real-size model and miniature model of daylighting duct system. We discussed effect of type of the parts on efficiency of daylighting duct system.展开更多
Different approaches have been introduced for the daylighting system to reduce energy consumption, but they were not populated due to complex, high cost, and insufficient designs. There has been a recent problem in ac...Different approaches have been introduced for the daylighting system to reduce energy consumption, but they were not populated due to complex, high cost, and insufficient designs. There has been a recent problem in achieving uniform distribution of sunlight at a destination deep inside the building. Therefore, we propose a system to achieve high illumination by illuminating the surface of the absorber (optical fibers) uniformly. To capture sunlight, parabolic reflector and Fresnel lens are used. Different reflectors and lenses are considered, compared, and investigated to direct uniform light, which solves the heat problem, into the optical fibers. In addition, this study includes comparison between fiber-based daylighting systems. The proposed system has been verified through simulation and experimental results.展开更多
The objective of this paper is to design units with well-lighted environment and low-energy consumption in the apartment building. Their daylight and energy performance can be determined by the building shape and orie...The objective of this paper is to design units with well-lighted environment and low-energy consumption in the apartment building. Their daylight and energy performance can be determined by the building shape and orientation. The paper initially produced the results of illuminations and energy efficiency using the daylight and thermal simulations by Autodesk ＂ECOTECT＂. It then provided the comparison on simulation results of two type buildings： Flat-type and L-type apartment. The available options for the design incorporating the environmental performance have less flexibility in fiat-type apartments than in L-type ones. The best unit in the fiat apartment is fixed from -45 to 45 degrees rotation, however, that in the L-type one can change depending on rotating the building. Moreover, if the upper level units had the appropriate environment, the lower level could have larger window areas in order to meet those daylight performance needs. Results show that the facade design should have the different window areas depending on the location of each unit. It can assist in the comfort and low-energy consumption design by using simulation tools that achieve the more predictable understandings.展开更多
This work explores three patterns of occupants’ control of window blinds and the potential influence on daylight performance of an office room in a tropical climate. In this climate, windows are frequently obstructe...This work explores three patterns of occupants’ control of window blinds and the potential influence on daylight performance of an office room in a tropical climate. In this climate, windows are frequently obstructed by curtains to avoid glare, despite the daylighting and the exterior view. The consequences are obstructed outside view, poor daylight quality and dependency on artificial lighting. This paper assesses the impact on available daylight using parametric analysis based on daylighting dynamic computer simulations using Grasshopper and Daysim software, combining WWR （window-to-wall ratio） （40% and 80%）, SVF （sky view factor） （small and large） and occupant behavior （active, intermediate and passive users）. The user patterns are based in an office buildings survey that identifies preferences concerning daylight use and control of shading devices. The daylight performance criteria combine UDI （useful daylight illuminance） （500-5,000 lux） and illuminance uniformity distribution. Results confirm the impact of occupant behavior on daylighting performance. The optimum combination of external shading devices, high SVF and high window size results in a useful daylighting for 1/3 of the time for passive users and 2/3 for active users.展开更多
In the subtropical zone of China, a large number of old factory buildings rich in industrial historical and cultural value have been transformed into art studios. In the existing research on building renovation, there...In the subtropical zone of China, a large number of old factory buildings rich in industrial historical and cultural value have been transformed into art studios. In the existing research on building renovation, there are still problems such as insufficient lighting, low uniformity, and ignoring the effect of glare in the lighting environment of buildings after transformation. To fill this research gap, this paper provides a daylighting design strategy for these factory buildings in subtropical zones to ensure that the transformed art studios can offer an excellent indoor daylighting environment. Through the control variable method, the window-to-wall ratio, the form of external windows, and the visible light transmittance of glass are set with quantitative and variable values, and a design strategy that meets the requirements of international general daylighting standards is obtained step by step through the simulation. The daylight factor, uniformity, daylight autonomy, and dynamic glare probability are used in this research process to measure whether the daylighting strategy meets the daylighting requirements of the CIBSE Lighting Guide for art studios. The results show that the average indoor lighting coefficient can be increased from 1.29 to 6.18, and the minimum value of the lighting coefficient can be increased from 0.4 to 4.4 by enlarging the windowed wall ratio from 1:30 to 1:3, using the combination method of the horizontal window, skylight and skylight recommended by the analysis results, and selecting veneer glass with 88% transmittance. This allows for better uniform lighting inside the building and reduces glare. This conclusion can support the lighting performance design of industrial buildings in the future.展开更多
Use of natural daylight in the building is energy saving with respect to illumination levels and health benefits.However in,the hot and dry climatic zone increase in daylight availability may result into thermal ingre...Use of natural daylight in the building is energy saving with respect to illumination levels and health benefits.However in,the hot and dry climatic zone increase in daylight availability may result into thermal ingress.This might lead to excess energy conservation.The aim of this paper is to evolve the methodology which could be used as a pre design tool for assessing the lighting provisions and thermal performance of spaces within buildings adopted by designers during the design process.The field measurements were conducted on the liveable spaces of a dwelling unit of the Nagpur region.Simulation studies using Ecotect Analysis 2011 was conducted for both illumination and thermal energy.The field measurements were compared with the simulated results.It has been found that the percentage difference(PD)between the Ecotect measurements(EM)and field measurements(FM)for both thermal loads and an illuminance level was less than 15%,the simulated model was considered precise for further study.The result imply that the simulated model would be ample for designers to evaluate the parameters associated to wall to window ratio,shading devices with respect to orientation of the building which helps to achieve the optimum useful daylight index.展开更多
The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the...The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the reflectances of building surfaces and glazed areas are important parameters in the daylighting design of buildings. Glazing systems can cut energy consumption and associated pollution sources, reduce peak demand, enhance daylighting performance and improve occupant comfort. This paper presents the results of a numerical and experimental comparison between the performances of an office building with and without external sunscreens. The aim was to analyse the illuminance distribution and some investigations have also been made with regards to the effect on daylight in rooms when sunscreens are used. The experimental results were obtained using an office building scale model and sky simulator. The numerical results were obtained through radiance, the ray-tracing program, to accurately predict the light levels and produce photo realistic images of the architectural space in all sky conditions： Illuminance values were obtained respectively through reference point measurements. The daylighting performances of the office building model with and without the sunscreens have been compared and analysed.展开更多
This study＇s purpose is to evaluate and analyse the indoor daylight quality in Pediatrics Ward in JUH （Jordan University Hospital）. It conducts an investigative analysis associated with an evaluative approach for t...This study＇s purpose is to evaluate and analyse the indoor daylight quality in Pediatrics Ward in JUH （Jordan University Hospital）. It conducts an investigative analysis associated with an evaluative approach for the daylight situation in patient rooms in the children section. A multi-method approach used including on-site measurements, and building model to develop a framework for lighting design in Paediatrics Ward, in order to determine whether the current quality meets the recommended values for patient rooms by CIBSE or not. The study considered the following variables： the differences in daylight environments （illuminance, luminance level, daylight factor）, and the physical environment properties of patient rooms in the hospital. The study found that the indoor daylight performance in terms of illuminance, luminance level, and daylight factor in east patient rooms are higher than the recommended values by CIBSE in the area nearest to glass window at the morning and less than the recommended values in the depth of the room at afternoon. Therefore, solar reflective technologies and shading system must be provided for enhanced day lighting control, avoid excessive glare and to guarantee a good level of visual comfort for patients and staff while reducing artificial lighting demand.展开更多
基金2024 Science and Technology Commissioner Service Group's Emergency Science and Technology Research Project for Wind Disaster Relief in Hainan Province(ZDYF2024YJGG002-8)China Huaneng Group Co.,Ltd.Headquarters Technology Project,Optimization of Photovoltaic Vegetable Greenhouse Structure and Research on Planting Agronomy in Tropical Regions(HNKJ22-HF77)。
文摘In the tropical regions represented by Hainan,there are abundant solar and thermal resources,and it is relatively suitable for the construction of photovoltaic greenhouse(PVG).However,the construction of PVG still relies mainly on experience and is incapable of quantifying the balance between the photovoltaic(PV)generation and the light requirements for agricultural production.As a result,actual PVGs are primarily PV-based,without carefully considering the needs of agricultural daylighting.To quantify the influence of the design parameters of PVGs and the layout of PV panels on the internal daylighting of serrated PVGs,and to optimize the daylighting design of the roof,this paper utilizes the Design Builder software to establish gradient models for a multi-span serrated-type PVG in tropical regions.Gradient models were established in terms of aspects,namely span,width of longitudinal/transverse daylighting strip,height,roof angle,and photovoltaic panel coverage rate(PCR).Daylighting in the greenhouse of each gradient model was simulated,and with the annual average daily light integral(A_(DLI))and distribution uniformity(DU)as evaluation indicators,the influence of various design parameters on the daylighting inside the greenhouse was quantified.The result reveals that:(1)PCR is the decisive indicator for daylighting in the PVG,and a function between PCR and the A_(DLI) is derived as A_(DLI)=-15.5 PCR+16.841;(2)Increasing the width of longitudinal daylighting strip significantly improves the A_(DLI) and enhances DU while increasing the span has a noticeable effect on improving A_(DLI) but does not significantly enhance DU;(3)Increasing the eave height without changing PCR does not enhance A_(DLI) but effectively improves DU;increasing the transverse daylighting strip and adjusting the roof angle hardly improves A_(DLI).In summary,it is recommended that the optimal span for PVGs in tropical regions be set within the range of 6.5-8.0m,and the eave height be set within the range of 2.5-3.5m.Preferably,the longitudinal daylighting strip with a width ranging from 0.5-0.8m should be installed.Based on the above relationship function,the PCR can be calculated according to the appropriate light demand for the cultivated crops.The daylighting design theory proposed in this paper can provide a theoretical basis and reference for the healthy development of the PV industry in tropical regions.
文摘This paper explains how the optimized classrooms were selected and the results that were achieved by the optimizations carried out and finalized.The context of the research is the city of Concepción,in Chile.Virtual models of classrooms were evaluated using the Radiance software.We used a methodology that allowed us to determine the luminous conditions under different types of skies,seasons of the year and times of the day.The evaluation of the typologies was performed based on three defined criteria,in order to achieve the stated design objectives.We defined the optimal solutions for each orientation and,finally,we stated design recommendations for daylit classrooms to ensure the visual comfort of the students.These recommendations link all that found in the initial analysis with that found in the optimization stage.
文摘Daylight is a fundamental element to obtain built environments that promote environmental comfort and energy efficiency. However, strategies that enhance the building daylight performance can affect its thermal energetic performance. In this sense, research that addresses these aspects at the same time is considered essential. The objective of this paper was to evaluate the daylighting and thermal-energetic performance of administrative environments in a public institution, and to propose strategies that will enhance the use of daylight and lower energy consumption. Therefore, for future projects, and considering new buildings, and retrofit, this research will be an important reference. The research was developed through a case study of an administrative building model, in which the characteristics of solar orientation, light shelf use, glass type, and light and dark colors in walls were modified and combined, deriving it into models proposed. The daylighting performance evaluations were performed through dynamic simulation with the Rhinoceros for Diva software, and the thermal-energetic performance evaluations with the EnergyPlus software. The results of the work showed that a suitable solar orientation has a great impact on the automation of daylight and the energy consumption of the evaluated models, followed by the type of glass and the use of the light colors in internal walls, and that the use of artificial lighting with dimerization is fundamental as a complement to the daylight autonomy. For the boundary conditions of the study, the use of light shelves modified neither the daylight performance nor the thermal-energetic performance of the evaluated models.
文摘Daylighting studies in buildings are key parts of environmental analysis and can be easily conducted at the early stages of design as part of environmentally responsive building design as well as to inform the final architectural layout and interior design. The main aim of this study is to demonstrate how such daylighting studies can be completed at the early stages of design and, at the same time, to show the impact of window design and positioning on building indoor environments. The paper is focused on a study of window influence on room daylighting in residential buildings and computer lighting simulations in software packages： Windows Daylighting System and Autodesk Ecotect Analysis, have been carried out for different style and positioning of windows using several case studies. The main findings clearly indicated that not only the window size and style matters, but also the positioning of windows considering external walls which would make a significant influence on room daylighting levels and, therefore, such daylight studies are very important for the early stage of environmental analysis during building design.
文摘Improving daylighting strategy is a mandatory step to achieve visual enjoyment and energy saving in buildings. Psycho, physiological effects and energy performance have to be investigated in order to define a range of different daylighting strategies, thanks to daylighting devices and climate based daylight modeling. Daylighting optimization ensures indoor healthier rooms, reduces electric light consumption and cuts the risk of glare. The best way to achieve these targets is to define users lighting needs, based on visual targets and to draw up some green measures to reduce electricity demands. Involving new climate-based daylight modeling metrics aims at defining proper illumination targets, in order to drastically reduce electrical lights, as well as reducing thermal loads deriving from cooling and HVAC （heating, ventilation and air conditioning） systems.
基金Key Scientific and Technological Research Projects of Henan Province(072102240027) Doctor Foundationof Henan Polytechnic University(648602)Postgraduate Degree Thesis Innovation Foundation of Henan Polytechnic University(644005)
文摘In order to meet the requirements of indoor illumination, a LED daylight lamp model was designed, it can replace traditional fluorescent lamp without insteading additional power supply establishment. The optical properties of the model were simulated using optical analysis software. Its luminous efficiency is about 30.4 lm/W, and the illuminance is about 38 lux when the distance is 1.5 m between the center of the model and measured spot. With the theoretically-optimized design of LED model, experiments based on the results of the optimal simulation in the laboratory were conducted to verify the performance of the proposed LED model, it reaches a power factor of about 0.8 at 6 W. The simulation results are very similar with the measured values. It is testified that simulative method is one of the effective tools for LED lighting optical design.
文摘The following article has been retracted due to the fact that it cannot be accepted as Duplicate Publication. The Editorial Board takes a very strong respect to the author’s situation on this matter. This paper published in Journal of Power and Energy Engineering Vol.3 No.4, April 2015, has been removed from this site.
基金Funded by Shan Xi Research Fund for Returned Scholars (No.2007-25)Shan Xi Open Fund for Key Laboratory(No.2008012013-7)The Specialized Fund for The Innovative of College Students of Tai Yuan City(No.09122018)
文摘The transparent C-doped TiO2 nanostructure films were fabricated on the silicate glass substrates by sol-gel spin-coated method. The as-prepared films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, UV-visible absorption spectra （UV-vis） and X-ray photoelectron spectroscopy （XPS）. The photocatalytic activity was evaluated via the photocatalytic oxidation of methylene blue in aqueous under daylight irradiation at room temperature. The results show that the daylight-induced photocatalytic activities of the as-prepared films are improved by the C-doping. The calcination temperatures significantly affect the morphology, microstructure and photocatalytic activity of the as-prepared samples. At 723 K, the C-doped TiO2 films exhibit the highest photocatalytic activity due to the synergetic effects of good crystallization, appropriate oxygen vacancies and strong absorption in the near UV and visible-light region.
文摘Currently, daylighting ducts system is widely used as a daylighting device. Generally, daylighting duct system efficiently takes light from outside during the day, and conveys daylight to required location through light duct manufactured by high reflectance mirror. Daylighting duct system can convey daylight to underground space that has no windows opening to external space. Daylighting system is composed of light collection part, light guide part and light emission part. Efficiency of daylighting system is depending on type of each part used in the system. However, it is very difficult to estimate exact light flow in the system considering type of the parts. Authors performed measurement experiments to make clear the light flow with real-size model and miniature model of daylighting duct system. We discussed effect of type of the parts on efficiency of daylighting duct system.
文摘Different approaches have been introduced for the daylighting system to reduce energy consumption, but they were not populated due to complex, high cost, and insufficient designs. There has been a recent problem in achieving uniform distribution of sunlight at a destination deep inside the building. Therefore, we propose a system to achieve high illumination by illuminating the surface of the absorber (optical fibers) uniformly. To capture sunlight, parabolic reflector and Fresnel lens are used. Different reflectors and lenses are considered, compared, and investigated to direct uniform light, which solves the heat problem, into the optical fibers. In addition, this study includes comparison between fiber-based daylighting systems. The proposed system has been verified through simulation and experimental results.
文摘The objective of this paper is to design units with well-lighted environment and low-energy consumption in the apartment building. Their daylight and energy performance can be determined by the building shape and orientation. The paper initially produced the results of illuminations and energy efficiency using the daylight and thermal simulations by Autodesk ＂ECOTECT＂. It then provided the comparison on simulation results of two type buildings： Flat-type and L-type apartment. The available options for the design incorporating the environmental performance have less flexibility in fiat-type apartments than in L-type ones. The best unit in the fiat apartment is fixed from -45 to 45 degrees rotation, however, that in the L-type one can change depending on rotating the building. Moreover, if the upper level units had the appropriate environment, the lower level could have larger window areas in order to meet those daylight performance needs. Results show that the facade design should have the different window areas depending on the location of each unit. It can assist in the comfort and low-energy consumption design by using simulation tools that achieve the more predictable understandings.
文摘This work explores three patterns of occupants’ control of window blinds and the potential influence on daylight performance of an office room in a tropical climate. In this climate, windows are frequently obstructed by curtains to avoid glare, despite the daylighting and the exterior view. The consequences are obstructed outside view, poor daylight quality and dependency on artificial lighting. This paper assesses the impact on available daylight using parametric analysis based on daylighting dynamic computer simulations using Grasshopper and Daysim software, combining WWR （window-to-wall ratio） （40% and 80%）, SVF （sky view factor） （small and large） and occupant behavior （active, intermediate and passive users）. The user patterns are based in an office buildings survey that identifies preferences concerning daylight use and control of shading devices. The daylight performance criteria combine UDI （useful daylight illuminance） （500-5,000 lux） and illuminance uniformity distribution. Results confirm the impact of occupant behavior on daylighting performance. The optimum combination of external shading devices, high SVF and high window size results in a useful daylighting for 1/3 of the time for passive users and 2/3 for active users.
文摘In the subtropical zone of China, a large number of old factory buildings rich in industrial historical and cultural value have been transformed into art studios. In the existing research on building renovation, there are still problems such as insufficient lighting, low uniformity, and ignoring the effect of glare in the lighting environment of buildings after transformation. To fill this research gap, this paper provides a daylighting design strategy for these factory buildings in subtropical zones to ensure that the transformed art studios can offer an excellent indoor daylighting environment. Through the control variable method, the window-to-wall ratio, the form of external windows, and the visible light transmittance of glass are set with quantitative and variable values, and a design strategy that meets the requirements of international general daylighting standards is obtained step by step through the simulation. The daylight factor, uniformity, daylight autonomy, and dynamic glare probability are used in this research process to measure whether the daylighting strategy meets the daylighting requirements of the CIBSE Lighting Guide for art studios. The results show that the average indoor lighting coefficient can be increased from 1.29 to 6.18, and the minimum value of the lighting coefficient can be increased from 0.4 to 4.4 by enlarging the windowed wall ratio from 1:30 to 1:3, using the combination method of the horizontal window, skylight and skylight recommended by the analysis results, and selecting veneer glass with 88% transmittance. This allows for better uniform lighting inside the building and reduces glare. This conclusion can support the lighting performance design of industrial buildings in the future.
文摘Use of natural daylight in the building is energy saving with respect to illumination levels and health benefits.However in,the hot and dry climatic zone increase in daylight availability may result into thermal ingress.This might lead to excess energy conservation.The aim of this paper is to evolve the methodology which could be used as a pre design tool for assessing the lighting provisions and thermal performance of spaces within buildings adopted by designers during the design process.The field measurements were conducted on the liveable spaces of a dwelling unit of the Nagpur region.Simulation studies using Ecotect Analysis 2011 was conducted for both illumination and thermal energy.The field measurements were compared with the simulated results.It has been found that the percentage difference(PD)between the Ecotect measurements(EM)and field measurements(FM)for both thermal loads and an illuminance level was less than 15%,the simulated model was considered precise for further study.The result imply that the simulated model would be ample for designers to evaluate the parameters associated to wall to window ratio,shading devices with respect to orientation of the building which helps to achieve the optimum useful daylight index.
文摘The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the reflectances of building surfaces and glazed areas are important parameters in the daylighting design of buildings. Glazing systems can cut energy consumption and associated pollution sources, reduce peak demand, enhance daylighting performance and improve occupant comfort. This paper presents the results of a numerical and experimental comparison between the performances of an office building with and without external sunscreens. The aim was to analyse the illuminance distribution and some investigations have also been made with regards to the effect on daylight in rooms when sunscreens are used. The experimental results were obtained using an office building scale model and sky simulator. The numerical results were obtained through radiance, the ray-tracing program, to accurately predict the light levels and produce photo realistic images of the architectural space in all sky conditions： Illuminance values were obtained respectively through reference point measurements. The daylighting performances of the office building model with and without the sunscreens have been compared and analysed.
文摘This study＇s purpose is to evaluate and analyse the indoor daylight quality in Pediatrics Ward in JUH （Jordan University Hospital）. It conducts an investigative analysis associated with an evaluative approach for the daylight situation in patient rooms in the children section. A multi-method approach used including on-site measurements, and building model to develop a framework for lighting design in Paediatrics Ward, in order to determine whether the current quality meets the recommended values for patient rooms by CIBSE or not. The study considered the following variables： the differences in daylight environments （illuminance, luminance level, daylight factor）, and the physical environment properties of patient rooms in the hospital. The study found that the indoor daylight performance in terms of illuminance, luminance level, and daylight factor in east patient rooms are higher than the recommended values by CIBSE in the area nearest to glass window at the morning and less than the recommended values in the depth of the room at afternoon. Therefore, solar reflective technologies and shading system must be provided for enhanced day lighting control, avoid excessive glare and to guarantee a good level of visual comfort for patients and staff while reducing artificial lighting demand.
