• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.5
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• pp.9-17
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• 1996

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.22-27
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• 2007

• KIEAE Journal
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• v.8 no.1
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• pp.53-60
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• 2008

The daylighting affects on the human biological cycles and physiological alterations. Daylighting is also an important element in visual comfort and it sometimes influences the quality of vision. Therefore the absence of natural light during the day brings contradictory result. To solve the problems of natural light lack and provide sufficient daylight in interior spaces, it might be necessary to apply some daylighting systems. One of these systems, light pipe system, which is simple, cheep and easily constructed, is very useful to apply for small buildings. The light pipe is simple means of directing daylighting (diffuse and direct lighting)into interior space. In order to application of light pipe system in Korea, it is necessary to optical data of light pipe system. This study aims to evaluate preliminary experiment of the daylighting environment of light pipe system. Light pipe system, that aspect ratio is 1:2(diameter and length), was installed in a windowless mock-up with $27m^2$. The mock-up model was constructed as a prototype of Korean office surface. Illuminance was measured with a Topcon IM-5 Luxmeter to evaluate the distribution of the illuminance on a floor. The indoor and outdoor illuminance and the internal/external illuminance ratio are compared to discuss with in the graphs. Luminance was measured with Radiant imaging Promertric 1400 that is digital photometer to evaluate the distribution of luminance on interior surface. The contrast of luminance is discussed with table and graphs.

• KIEAE Journal
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• v.6 no.2
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• pp.3-10
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• 2006

This study assessed the visual performance of luminous environment by the lightshelf. The subject survey method was used and results are presented and analyzed. The lightshelf daylighting system was developed by LAEL at KH University and was applied on the window of a mock-up office. The questionnaire for assessing visual performance contains 9 questions with 7 grade bipolar scales. The experiment was conducted during the bright part of the day from noon to one thirty on June 7, 2006. The questionnaire for assessing visual performance contains 9 questions with 7 grade bipolar scales. During the experiment was carrying out, the work plane illuminance and luminous distribution at surrounding the windows was measured. The semantic differential rating data of experiment were analyzed by t-test and factor analysis using SPSS 12.0 statistics package. The visual performance of the lightshelf was more positive. The factors affecting the visual performance are task performance and visual comfort. The subjects were more comfortable in a room installed with lightshelves on both the task performance and the visual comfort aspect. Therefore, the application of sloped lightshelf daylighting system improves visual performance of luminous environment.

• 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.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.19-26
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• 2009

This study is performed by method for the influx of natural light in underground space. to solve the several negative underground issues make the covered courtyard and high reflected wall toward the adjacent space. for illuminance level test of sunken garden space, the adjacent space size is $15M{\times}9M{\times}12M$ sunken Garden with space to install the ceiling on the size of the companion light performance analysis, and seasonal changes derived by the light of changes in performance. In addition, increase the distance of the wall and the adjacent space and estimate the average at true time P.M12. The resulting data indicate that the road was an average lux DESKTOP RADIANCE of the modeling and analysis was conducted.

• KIEAE Journal
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• v.2 no.2
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• pp.39-44
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• 2002

Recently, underground spaces can be usually applied to the alternative of land use for parking. However, lack of window and natural light are among the most cited drawbacks associated with dark image of underground. If underground parking lots are designed to be positive and safe environment for people, openings for daylighting will play a significant role. The natural light and unobstructed view to outdoor are main elements to create optimal underground parking lots. This paper focuses on investigating the actual day lighting conditions and evaluating the day lighting performance of openings as potential lighting resources. For the study, the field measurements and Questionnaire surveys are conducted. And then, the day lighting performance of underground parking lots based on opening geometry and orientation are evaluated by scaled model experiments. As results, the feelings of safety and orientation of underground parking lots are improved by openings for day lighting regardless of the sizes. The required illuminances (daylight factor 0.5%) for underground parking lots can be satisfied in the skylight opening ratio of 4% or more.

• KIEAE Journal
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• v.7 no.5
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• pp.41-46
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• 2007

The lightshelf system, a horizontal shading and light redirect device, should improve the visual environment by optimal light distributions and intense illumination levels of a interior. This study aims to evaluate the daylighting performance of window integrated lightshelf systems by computer simulations. For the study, the standard office plan is analyzed through the field surveys. And then, the various lightshelf types attached window systems are picked out from existed research results. The max, minimum and average illuminance levels of interiors and illuminance distributions are evaluated by Lightsacpe 3.2 programs based on the installing height, shape type and moving angle of lightshelfs. As results, it is suggested that the optimum lightshelf shapes are the height 1.8m and the width 600mm. Also, in mixed lightshelf, the outside width 600mm, inside width 400 are efficient on indoor daylighting performance.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.8
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• pp.395-401
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• 2015

Recently, many research studies have been carried out on the efficiency of light-shelf daylighting systems, especially comparing performance improvements and the limitations of reflective surfaces and their lighting performance. In this study, a crystal face reflective surface is proposed. The objective of the study is to evaluate the lighting performance of a crystal face light-shelf through a performance study. The performance study was carried out in a full scale test-bed in order to calculate the light distribution and energy consumption utilizing the standard indoor illumination as an index. The conclusions of the performance study are as follows. 1) The optimal angle of incidence for daylighting for both the operable flat type light-shelf and the crystal face light-shelf are taken in the natural environment on the dates of the winter and summer solstices, as well as the autumn and spring equinoxes. 2) The application and installation of the crystal face light-shelf can produce a 29.9%~34.3% increase of light distribution within the indoor space. However, the increase of light distribution can also lead to a decrease in the uniformity ratio, a design challenge that should be considered when applying a crystal face light-shelf. 3) It is possible to achieve a 7.98%~13.3% greater reduction in energy consumption when applying a crystal face light-shelf than when applying a flat type light-shelf. The increase in the number of crystal faces should concur with the analysis of the energy reduction. A limitation of the study is that only one predetermined pattern was performance tested for a crystal face light-shelf. In order to carry out further research on crystal face light-shelves, additional performance studies are needed based on alternative patterns and designs.