• Journal of the Korean Solar Energy Society
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• v.35 no.5
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• pp.1-10
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• 2015

Whereas recent domestic buildings and industrial facilities are being constructed as large as possible, the daylighting systems for the large space have rarely been developed. Domestic situation has been reported as only several small or medium sized daylighting systems have been developed, and the large scaled systems have entirely being imported from abroad. We have developed a large scaled daylighting system for the big space. The developed system have been evaluated in terms of the average system efficiency and daylighting factor. Each results are shown with tabulated experimental data.

• KIEAE Journal
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• v.8 no.1
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• pp.45-52
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• 2008

Daylighting systems can improve the luminous quality of indoor environment and reduce the building's electric lighting energy consumption. For designing good daylighting, place the light where it is desired and avoid excessive contrasts, glare and high light levels. Sun scoop, light scoop and sun catcher systems have been used for alternative systems compared to other natural lighting systems. This study aims to evaluate daylighting performance of sun scoop, light scoop and sun catcher systems using scale model experiments. For the purpose, the 1/10 scale models of the systems were made as the same areas of glazing(10 percent of floor area) on the top of the center roof. Totally 15 measuring points of illuminance on the horizontal work plane were monitored from 09:30 to 12:30 on October 29, 2007. Agilent data logger and photometric sensors Li-cor were used. As the results, the topside lighting systems can improve the illumination uniformity than side lighting and top lighting. However, the appropriated shading system should be integrated to prevent the direct sunlight.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.36-43
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• 2004

The purpose of this paper was development of modified horizontal daylight duct for reflector of light intake, location of outlet diffuser and size as applicable daylighting system for buildings and, verified applicable possibility base on analysis of daylighting performance through full-scale model test. Experimental result showed that ratio of illumination for light duct was measured 0.3∼0.4％ in interior of a room on clear sky. Also, light duct had wide distribution of illumination than duct about 150[cm] and was decided efficient lighting energy saving because of high daylight performance in case of application actual building during daytime.

• KIEAE Journal
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• v.6 no.4
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• pp.25-32
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• 2006

Mock-up model can be applied to measure accurate performance data but difficult to apply the variables in experiment. There can be a slight experiment errors in Scale model, but various parameters can be applied for a objective experiment. This paper aims to compare the daylighting performance in 1, 1/5, 1/10 scale model of offices and analyze the experiment errors to certificate the influence of model experiment. To analyse daylighting performance, a comparison of a Mock-up model, sized $12.0m(w){\times}7.2m(l){\times}3.7m(h)$, designed for experimentation of daylighting systems and its 1:5, 1:10 scale model. It has an identical configuration of reference room and the test room. For the test room, the lightshelf system was designed as Micro-4 reflective material. To assess work plane illuminance and light factor, photometric sensors of each room were installed at work-plane(6 points) and exterior horizontal illuminance (1 point). And 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 and luminance are discussed.

• 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.4 no.1
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• pp.11-20
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• 2004

Innovative daylighting systems in buildings in various climatic zones around the world have been developed under the IEA SHC Task21. The performance assessment were obtained by monitoring the most systems using full-scale test model rooms or actual buildings under real sky conditions. This study aims to analyze the configuration and monitoring system of the nine Mock-up models of the IEA SHC Task21 comparatively. For the purpose, the geometry of the test rooms (length, width, height, window area, glazed area and occupied), reflectance of walls, floor and ceiling, transmittance of glazing (transmittance for hemispherical irradiation, normal irradiation and U-value) were compared. And equipment for measurement (manufacturer, range, calibration, maximum calibration error, cosine response error, fatigue error), and data acquisition system (manufacturer, type, number of differential analogue input channels, A/D converter resolution in bits, data acquisition software) were also analyzed comparatively. Some findings of these experimental methodology of standard monitoring have been proven to be a valuable one for future assessment of advanced daylighting systems in our country.

• KIEAE Journal
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• v.10 no.4
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• pp.137-145
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• 2010

Active sunlighting systems have been applied to deliver sunlight into the indoor space where natural light is insufficient, mainly because of the congested high-rise buildings in urban areas. Among various active sunlighting systems, a mirror sunlighting system which is simple structure and economically reasonable has been widely used in different types of spaces such as underground, north facing place and atrium. This study was to evaluate the mirror sunlighting systems, which were consisted of the first mirror of $3.5m{\times}2.5m$, the eight sets of the second mirrors of $1.0m{\times}1.25m$ and a sun tracker. Ten sets of the systems were installed for 40 apartment living rooms, the configuration of $3.5m(W){\times}4.0m(D){\times}2.5m(H)$ where sunlighting were not possible due to high retaining walls located in the front of the living rooms. The 45 HOBO data logger sensors for the indoor illuminance were equipped and 2 Li-cor photometers for outdoor illuminance. Both indoor and outdoor horizontal illuminances were monitored every second from 9am to 3pm on 17 January 2010 under clear sky condition. The results showed that the indoor illuminance of installed mirror sunlighting system was significant relationship with outdoor illuminance and increased the indoor illuminance level by 4.2 times on the whole floor space, by 8 times on the sun patch space of 6m2 and even by 2 times on the no sun patch space. In addition, the luminous conditions of the living room under real sky conditions met the KS recommendation for difficult task (600-1000-1500 lux) such as sewing and reading on whole floor space and sun patch space. It was proved that the benefits of mirror sunlighting systems included an effective technology for penetrating daylight into indoors where sunlighting was not possible and improving occupants' satisfaction and health, and contributing to energy saving in apartments during daytime.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.13-22
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• 2005

This research aimed to generate two points of daylighting application as follows: 1) providing daylight performance data with a variety of glazing materials for a large window and 2) designing and evaluating an experimental type of differentiated window. For this purpose, we compared the daylight and distribution performance of new defined type of window configuration to the conventional window counterpart with a variety of glazing materials. The comparison was made for a deep, south-facing perimeter zone with large window, without any interior obstruction. The conventional window is the base single homogeneous glass pane, where as the differentiated window uses of two different glazings; an upper daylight glazing with high visible transmission and lower view window with lower transmittal glass. The daylight performance data was translated into a ratio between outdoor illuminance and the interiors. The simulated analysis of the conventional window indicates that the interior light levels have been changed proportionally dependent on the transmittance of the applied glass. The comparison of daylight distribution analysis showed that the differentiated window has lots of photometric advantage by the optical function of upper daylight window. In particular, the contribution of higher daylight window into deep rear space must be stressed for daylighting application.

• KIEAE Journal
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• v.6 no.1
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• pp.17-24
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• 2006

Daylight is a critical factor in architecture, as it enhances the working efficiency and visual comfort of the people working inside. Even though, low transmittance glazing has been used in the most office buildings in Korea. And it is reduced visual comfort in a indoor environment. So, we need to evaluation of quality for various daylighting systems to improve visual comfort This study aims to evaluate the visual comfort in a indoor environment by different daylighting system. For the purpose, four different daylighting systems-conventional window, conventional window with interior lightshelf, differentiated window, differentiated window with interior lightshelf-were selected and a questionnaire survey with 50 subjects were conducted. The results are as follows. Regardless daylighting systems, a view has an effect on visual comfort. A conventional system and conventional system with lightshelf were highly correlated between comfort and warmth. In case of differentiated window system were correlated between comfort and openness. Also, differentiated window with interior lightshelf were highly correlated between comfort and stability.

• 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.