• Journal of the Korean Solar Energy Society
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• v.23 no.1
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• pp.48-56
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• 2003

Three of the leading computer daylighting simulation programs are compared with physical modeling techniques as a means of predicting daylighting performance of interior spaces. Lumen-Micro, Adeline and Lightscape are compared with physical model experiments under clear sky conditions. The comparative evaluations are conducted on analysis of daylight illuminance ratio(%) depending on model types. The estimated average errors are analyzed on 9.4% in Lumen-Micro, 6.3% in Adeline and 3.4% in Lightscape. Therefore, it is proved that three programs are useful for evaluating daylighting performance in our clear sky condition.

• KIEAE Journal
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• v.3 no.1
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• pp.45-56
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• 2003

New and innovative technologies for utilizing daylight in buildings have been developed for saving energies and improving visual environments. This study describes the most up-to date information available about the application and evaluation of advanced daylighting systems to enhance daylighting in non-residential buildings from IEA's Task 21. IEA's Task 21 consists on 4 subtasks such as "Performance Evaluation of Daylighting Systems(subtask A)", "Daylighting Responsive Controls(subtask B)", "Daylighting Design Tools(subtask C)" and "Case Studies(subtask D)". For the study, the configurations and characteristics of IEA's advanced daylighting systems are comparatively analyzed. As results, innovative daylighting systems are designed to redirect sunlight or skylight to areas which it is required without glare. These systems use optical devices that initiate reflection or refraction of sunlight and skylight. And they can be designed to actively track the sun or passively control the direction of sunlight and skylight. The comprehensive overview of innovative daylighting systems presented in this study helps designer to understand the advantages of daylighting in building and choose a suitable system for building in the earliest stage of the design process.

• Journal of the Korean Solar Energy Society
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• v.34 no.5
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• pp.101-108
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• 2014

The performance of the daylighting in buildings depends on building site and shape. As an energy saving design strategy, daylighting is a key issue in green building design. In this paper, the influence of the adjacent or obstructed building on daylighting performance of the office building in urban area was analyzed. A typical office building about 20 storeys with obstructed buildings has been modeled and simulated using Radiance. The parametric simulations have been performed to analyze the influence of the daylighting performance (illuminance, luminance) of the analyzed office. The results show that the possibility of the glare was decreased when the obstructed building is located in south, also the illuminance level was significantly decreased. When the obstructed building is located in north, the changes of the illuminance level and luminance possibility were somewhat small compared to the unobstructed condition. The daylighting performance of the analyzed building was most affected by the obstructed building in winter season.

• KIEAE Journal
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• v.9 no.1
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• pp.23-30
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• 2009

A lightcourt design is typically used to address issues concerning aesthetics, feeling, and mood. From the view point of environmental aspect, as an ecological shaft space, it plays a key role in controlling inner quality. In particularly, the lightcourt concept allows the exploitation of daylighting by bring natural light into the center of the building, thus eliminating dark deep spaces. Additionally, the lightcourt shades the inner space in summer. The amount of light available at the base of the lightcourt depends on a number of factors; translucency of the top, reflectance and the geometry of the space. In this paper is to exemplify a lightcourt configuration with a sloped wall. It promises the maximized a sense of freedom and daylighting availability. It is a matter of course that the lightcourt with open-top plays a role as a light source for the adjacent space to the lightcourt. A series of lighting simulation provides performance data of daylighting with changing photometric factors. For the case that a skylight is not available, an electric lighting design with metal halide lamps has been established to create luminous ceiling. As expected, a sloped lightcourt with open-top exposes its superiority of daylighting source. Ancillary considerations to enhance of daylighting potential for the adjacent space have been issued with performance data.

• Journal of the Korean Solar Energy Society
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• v.22 no.2
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• pp.61-69
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• 2002

Daylighting is a powerful vehicle of architectural expression and provides buildings a living quality due to constantly changing properties in intensity and color. As an environmental system, daylighting should be subjected to the same level of rigorous analysis and review that any environmental system receives. For example, increasing cooling loads and causing visual displeasure are easily occurred owing to the excessive sunlight through windows. Therefore, daylighting performance attributes and physical characteristics must be described qualitatively and quantitatively in early design process. In various architectural daylighting performance evaluation methods, the scale model experiment can be applied due to it's simplicity and usefulness. So, this study aims to evaluate the validation of scale model experiments in architectural daylighting performance. For the purpose, two scale model experiments under clear sky are conducted. And, the validation of the experiments are evaluated by computer simulations.

• Korean Institute of Interior Design Journal
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• no.37
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• pp.110-118
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• 2003

Computer simulation is one of the most useful techniques to predict daylighting performance and present visual image. In architectural and interior design practice, the Lightscape is commonly used often to produce persuasive images rather than physically accurate results. Therefore, this study is to validity the Lightscape as daylighting evaluation tool, in particularly performance and realistically visualization. For the purpose, an evaluation test model (12.0m$\times$7.2m$\times$3.0m) of side lighting window with lightshelf was selected. A 1:6 scale plywood physical model was made. Under clear sky condition, illuminance of 84 Interior point were measured. Lightscape was run on a 750 MHz Pentium PC running Windows 2000 under the same sky condition. And a photography image was compared to rendering image. The physical results of interior illuminance were within 8% between the scale model and Lightscape simulation. There were no differences between the photograph image and rendering image by Lightscape in the sight. Lightscape as visualization tool for daylighting performance was validated.

• KIEAE Journal
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• v.9 no.5
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• pp.105-113
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• 2009

Daylighting provides the opportunity for both energy savings and improved visual comfort. An accurate estimation of the amount of daylight entering a building is the key step for daylight designing. This research aims to assess comparative daylighting performance of four different configurations of fenestration in case of unilateral windows and their variation under clear and overcast sky conditions. The selected window openings in this study were single punched, double punched, multiple punched and clerestory, and the area was same for each type of window. The experiment was designed for an office space using 1/10 scale model. Daylighting performance was evaluated by measuring the illuminance on work-plane height using Agilent data logger and photometric sensor Li-Cor. Thecomputer program ECOTECT was also used to simulate the pattern of interior illuminance distribution. Clerestory window showed the best performance in term of both illuminance level and distribution in the experiment. Multiple punched window provided more uniform illuminance distribution than single punched window. Lowest daylighting performance in the experiment was shown by double punched window.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.39-50
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• 2004

One of the challenge for successful daylighting design might be to capture sunlighting that varies in both intensity and position and to deliver the luminous flux into the inner space as deep as possible. Conventional glazing apertures allow daylight in the outer 3.5m of a perimeter spaces. More advanced daylighting technologies can extend this daylighting depth by reflecting sunlight further from the windows within a deep floor area. For this purpose, this study developed light shelves based on performance evaluation with a mock-up model that constructed recently and measured under real sky condition. All these daylighting devices have a customized geometry developed from the solar path at a given latitude and utilize unique reflecting finishing to maximize the amount of redirection and diffusion of the daylight. This paper tells that the best daylighting penetration typically can be expected from using light-colored sloped external shelves.

• KIEAE Journal
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• v.6 no.2
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• pp.67-74
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• 2006

As sustainable design technologies, advanced daylighting systems with lightshelves have been developed and are currently under monitoring the daylighting performance. This study aims to evaluate the comparative daylighting performance of sloped lightshelf and conventional glazing window with mock-up model, reconstructed as a prototype of Korean office building, sized $12.0m{\times}7.3m{\times}3.7m$ ($w{\times}d{\times}h$) and $1.8m{\times}4.8m$($w{\times}h$) for the south facing side-window was installed on the rooftop of engineering building, Kyung Hee University in Korea. It has an identical configuration of reference room and the test room. For the test room, the sloped type lightshelf system was designed as 10mm transparency sheet glass, tilt angle degree $29^{\circ}$, and total sized 1.28m (interior length 0.88m, exterior length 0.49m). It consisted of daylighting collector, entrance glazing and reflector. To assess daylighting performance, the totally 37 measuring points for illuminance and 2 view points of luminance were monitored in every 30 minutes from 12:00 to 15:00. For the detailed analysis, photometric sensors of each room were installed at work-plane (8 points), wall (7 points), ceiling (3points), and exterior horizontal illuminance (1 point). Luminance of window, rare of the room was measured under clear sky. It is to be monitored by Agilent data logger, photometric sensor Li-cor and the Radiant Imaging ProMetric 1400. Comparisons with a light factor, increase-decrease ratio, uniformity, and luminance are discussed.

• KIEAE Journal
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• v.4 no.4
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• pp.45-52
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• 2004

Simulation of daylighting by computer program is a method to avoid unnecessary efforts in manufacture of its testing models, to reduce its measuring tolerances and be able to provide variations of various weather conditions as well. Many simulation programs on daylighting have been released freely or commercialized for selling, however, a demonstration of their availability and validity as a tool for evaluating daylighting performance is required since each one has its own characteristics. The objectives of this study lie in suggesting an application method of evaluation tools and demonstration of limits and characteristics so as to more easily determine the daylightingperformance in the very initial stages of planning for an arbitrary office space in which windows with daylight access are built. We produced scale model of the general light inducing type side lighting with lightshelfand ceiling, and the luminance (at 78 measuring points) and illuminance (at 84 measuring points) were measured in a clear sky. And a comparison of the measured values and the calculated values from a computer simulation using the Lightscape program was performed.