•A daylight factor model has been developed and experimentally validated for side window (cuboid shaped room).•The internal illuminance has been predicted for side window with the help of ...model.•Daylight factors and its components have been evaluated.
In the present paper, daylight factor model (DFM) has been developed for daylight aperture which has been experimentally validated for east oriented wall window under clear sky condition. The correlation coefficient (r) and the root mean square percentage error (e) are in the range of 0.96–0.99 and 5.1–7.9%, respectively. It has been seen that there is a close agreement between modeled and measured values. The annual average daylight factor (DF), sky component (SC) and internally reflected component (IRC) values for the room were determined to be 1.8%, 1.2% and 0.6%, respectively. It is observed that the south oriented window has maximum DF while it is minimum for north oriented window. It is also concluded that the window in the upper position allows higher illuminance of the rooms compared to a wall window toward the bottom of the room.
With respect to the light environment of the exhibition halls for Chinese calligraphy and painting works in the museums, the daylighting design in these display spaces have been studied, the key ...design factors, such as daylighting pattern, and arrangement of exhibits are examined and explored by field trips. Then, the display spaces are divided into diverse categories whose sky light environments are predicted by the demands of exhibits. Under changed daylighting situations, the daylight parameters, i.e., daylight factor (DF) and DF uniformity, discomfort glare index (DGI) and luminance distribution are calculated. Thus, the proper daylighting pattern and elements in the exhibition halls will be decided. The optimization strategies that optimize the parameters of daylighting patterns and elements are presented. The studies have shown that the daylighting quality will improved by the implement of optimal design, and good luminance environment in the calligraphy and painting exhibition halls are obtained.
The attempt at a more sustainable land use by increasing urban density may have a negative effect on the daylighting of residential buildings. In densely built areas, obstructions generated by the ...surrounding buildings can substantially reduce the available amount of daylight, causing poorly daylit spaces and a less healthy indoor environment with higher electricity consumption as a consequence of artificial lighting. European standard EN 17037, Daylight in Buildings, was established in 2018 to ensure appropriately daylit spaces. In this paper, a three-step methodology was developed to investigate the relationship between certain urban planning parameters and the daylighting of a typical room defined by specific (Slovenian) legislative restrictions about its geometry and minimum required window to floor area ratio, in order to establish the maximum densities of residential developments still fulfilling the minimum requirements for daylight provision defined by EN 17037. The results show that a relatively low urban density is required to fulfil the stipulations for minimum daylight provision for the deepest permissible room according to the Slovenian legislation. The impact of the development floor area ratio on the daylighting potential of buildings was identified as significant, followed by the site coverage, development layout, and building typology. Furthermore, the developed methodological approach clearly demonstrates a substantial potential for application in urban planning, with indoor daylight environmental conditions being linked to the planning of residential developments in the earliest stages of the project.
Daylight use in an atrium is particularly beneficial as the natural light can illuminate potentially dark core areas and decrease energy consumption from electric lighting. This study has ...investigated, for overcast sky conditions, the horizontal daylight levels in spaces adjoining atria and the vertical daylight levels on atrium well walls in atria. The daylight levels in the rooms and on the walls were derived from scale model measurements, theoretical calculations and predictions from the lighting simulation package Radiance. A comparison of measured data and modelling has validated Radiance simulations of atrium daylighting. The simulations show generally good agreement with theory while some limitations in the calculations used in determining the daylight factors in rooms with large widow area to total wall area ratios were observed. The average daylight levels in rooms displayed a linear relationship with the vertical daylight levels on the well wall. In terms of the well geometry and well façades (decided by the ratio of window area to solid wall area) and well surface reflectance, the variations of daylight level in the adjoining rooms have been analysed and some conclusions and design strategies for supporting preliminary design decisions are presented.
In this study, based on the current daylighting situation of a museum sculpture exhibition hall, the exhibition space is classified according to the daylighting requirements of the sculptures. ...Additionally, the daylighting pattern for the sculpture exhibition hall and the display layout of the exhibits are summarized. The daylighting parameters of the exhibition space under different scenarios are calculated. The exhibition space is simulated and analyzed under three daylighting conditions (flat skylights, flat skylights with side windows, and flat skylights with high side windows), and the daylighting parameters are optimized based on the daylighting patterns and components. It is discovered that with the combination of flat skylights and high side windows, the daylight factor (DF) and uniformity of daylighting (UD) of the sculpture exhibition as well as glare rating of the windows are the most favorable. Therefore, the appropriate daylighting pattern and components are determined, and the corresponding optimization strategy for daylighting is proposed. The results show that the daylighting optimization strategy proposed herein can improve the daylighting quality of the museum sculpture exhibition space and yield a suitable light environment.
In many urban cities, the external obstructions may significantly reduce the amount of daylight entering to the indoor space. The estimation of daylight illuminance gained via vertical fenestration ...is important in energy-efficient building design and operation. Practitioners welcome simple calculation aids established via comprehensive analysis. Such methods would give building professionals and students basic and concise insight into the independency of different daylight parameters. It is also very useful in initial architectural and building façade layout stage. Computer simulations can be conducted after the design schemes have been finalized. This paper presents manual calculation procedures to predict sky and externally reflected components at the interior points under various obstructed CIE sky conditions. Performance of the proposed method was evaluated by comparing with simulated results of a sophisticated lighting program and real scale measurements. The findings showed that the predictions based on the proposed approach were in good agreements with the simulated and measured outcomes. The study can provide a reliable practice for architects and building designers to estimate the internal daylight at early design and planning stage.
•A manual calculation tool was proposed to calculate SC and ERC.•The variations between the calculated and simulated results in terms of MAPE were less than 17%.•The variations between the calculated and measured results in terms of MAPE were less than 20%.•The R2s between the calculated and simulated outcomes were more than 0.89
A model to estimate daylight factor was investigated and validated using experimental hourly inside and outside illuminance data of an existing skylight integrated vault roof mud-house in composite ...climate of New Delhi. The daylight factor model was found in good agreement with experimental value of daylight factor. This model was modified for different practical horizontal surface levels inside the big and small dome rooms and validated using experimental measured data. The yearly average value of percentage daylight factor for big and small dome skylight rooms was determined as 2% and 6%, respectively. The total annual average artificial lighting energy saving potential of the skylight illuminance in the existing building was estimated as 973
kW
h/year; corresponds to 1526
kg/year of CO
2 emission mitigation. Hence, the annual carbon credit potential from skylight mud-house building is € 15.3/year.
Artificial lighting represents 15-30% of the total electricity consumption in buildings in Scandinavia. It is possible to avoid a large share of electricity use for lighting by application of ...daylight control systems for artificial lighting. Existing methodology for estimation of electricity consumption with application of such control systems in Norway is based on Norwegian standard NS 3031:2014 and can only provide results from a rough estimate. This paper aims to introduce a new estimation methodology for the electricity usage with the daylight- and occupancy-controlled artificial lighting in an office, which is both accurate and rapid. The method is validated for an office building in Oslo, Norway, using the experimentally obtained data and the data from the Building Management System.
The issue of how to fully utilize natural daylighting of public buildings is one of the greatest practical objectives for lighting savings. The rapid and accurate prediction of the daylighting ...coefficient at the early design stage can provide a quantitative basis for energy-saving optimization. However, it is not comprehensive to determine the design parameters according to experience. The key problem that is still facing designers is the interoperability between building modeling and energy simulation tools. In this paper, an integrated approach using a dataset created by building information modeling and artificial neural network technology is developed for the fast optimal daylight factor prediction of large public spaces at the early design stage. According to this approach, the value of daylight factors is calculated for different windowsill heights, window heights and widths by Autodesk® Revit and Ecotect Analysis to form a dataset. With this dataset, an artificial neural network model is established using the backpropagation algorithm to predict the relevant design parameters. With their large interior spaces, the reading areas of the aboveground five floors in Chengdu University of Technology Library are selected to carry out the daylight factor experiment and rapid prediction. A total of 495 groups of experimental data are randomly divided into training and testing sets. The root mean squared errors are below 0.1, which indicates a high regression model fitting. A total of 225,369 groups of prepared data are used in the prediction model to obtain the optimal windowsill height (1.0 m), window height (2.4 m) and window width (2.1 m) for five floors in the case of the maximum daylighting coefficient. Finally, a smartphone app is designed to facilitate daylight factor prediction without any experience in modeling and simulation tools, which is simple and available to realize prediction visualization and historical result analysis.
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