• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.17-23
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• 2004

Daylight illuminance levels in a small space were calculated using the Superlite program under limited conditions of the turbidity and thickness of condensible water of atmosphere. Three sky conditions(clear sky with direct sun, clear sky with no direct sun, overcast sky with no direct sun) were used. The atmospheric conditions significantly impacted the illuminance levels under especially a clear sky with direct sun. The overcast sky with no direct sun provided no difference for the illuminance levels in the space. As the calculation points moved away from a window, reflected illuminance levels gradually increased but direct illuminance levels significantly decreased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.18-26
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• 2009

Daylight responsive dimming systems are one of lighting control systems which are to control artificial lightings using available daylight for energy savings. This system is not popular because useful daylight is usually blocked by uncontrolled passive shading systems in buildings. It is necessary to integrate daylight responsive dimming systems and automata! roller shading systems. In this research, mock-up test is performed to analyze the daylight distributions in three different rooms for integrated systems. Roller shades are installed in two rooms. One is fully downed and the other is controlled by sun profile angle. The other room has no shading system as a reference room.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.133-136
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• 2005

Recently, a drain of energy resources is issued seriously. The daylight responsive dimming systems can reduce electric energy uses. But, we cannot predict amounts of energy-saving and accuracy of system performance. Therefore, the purpose of this study is a development of software for the system performance of daylight responsive dimming systems. The principle of this software based on luminous flux transfer method and finite elements method. The control algorithm of this software and daylight responsive dimming systems use the same algorithm. In addition the advantages of this software are use to same algorithm of daylight responsive dimming systems, electric power-luminous flux data and rates of frequency of sky conditions. Therefore, this software can predict more correct calculation about illuminance and amounts of energy-saving of daylight responsive dimming systems.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.97-100
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• 2008

The daylight responsive dimming system is an energy saving system that automatically controls lighting output of artificial lighting according to available daylight in inside, as well as keeps uniform workplace illuminance. The basic three components of the daylight responsive dimming system consist of a photosensor, a controller and a dimming ballast. This paper is a fundamental study of photosensor modeling for the daylight responsive dimming system. The correlation between photosensor illuminance on the ceiling and workplace illuminance is an important factor to accuracy of system performance, so that the purpose of this study is to improve accuracy for daylight responsive dimming system. This study performs to derive the optimized conditions of photosensor using the RADIANCE.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.35-44
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• 2010

Available daylight in inside offers comfortable view environment, and psychological and physical advantages to people in a room. Architectural design has a need for daylight prediction. But it is difficult to predict the illuminance values in daylight system. Using various Daylight simulation software is easy and simple, but we can find different results under the same conditions. This study compares with illuminance values from simulation (Lightscape 3.2, Relux 2007, Radiance 3.9) and Mock-up experiment with a same space and parameter of daylight (location of space and window, date, time and sky condition).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.1-9
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• 2009

A recent research trend on the Daylight Responsive Dimming Systems, using available daylight for energy savings, is to integrate automated roller shading systems and venetian blind systems which are vertically controlling daylight to indoor based on sun profile angle. Therefore, this paper suggests Grating Louver System into a pair glass as a new shading system, which can control daylight vertically and horizontally. The optimized spacing of louvers, which is to block direct sunlight into a space, was calculated. And then, the system was simulated for analysis and evaluation of characteristics of daylight by Desktop Radiance 2.0.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.58-62
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• 2017

In this study, the design conditions for the Korean-style glass greenhouse structure has been reduced to achieve the most efficient use of natural light. The AGI program was simulated for the optimal conditions of daylight in a glass greenhouse. From the results of daylight simulation, the axis position of the glass greenhouse's roof was not an important factor in the daylight effects regarding illumination and uniformity. In summer, there were long periods of daylight and high illumination levels. The illumination value of daylighting increased with increasing glass transparency value, and the illumination value was greatest at 14:00 hours. At this time, the rate of light variation according to the glass transparency was 89 [lux/%]. In addition, the optimal design conditions for the glass greenhouse were established, which were a $30[^{\circ}]$ or $150[^{\circ}]$ installation angle and higher transmittance of glass.

• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.36-48
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• 2008

This study examines the influence of control algorithms on dimming performance to determine appropriate control setting when direct/indirect lighting is controlled by a daylight dimming system. Computer simulation were performed for a small office with double skin envelope under various daylight conditions. A retractable fabric shading and Venetian blind were applied for internal and external envelopes under three CIE standard sky conditions. Unshielded and partially-shielded photosensors were used, and three control algorithms were applied for the sensors. In general, dimming level was too excessive due to the direct impact of light from lighting fixture to the photosensor. Providing insufficient lighting output, the unshielded photosensor completely failed to secure required illuminance under any daylight condition. When a partially-shielded photosensor was applied under clear sky, three setting points functioned effectively. Less sensitivity for the partially-shielded photosensor was effective to control the dimming system optimally with reasonable energy saving. However, the daylight dimming control system for direct/indirect lighting does not appear to be energy effective when photosensors without enough shielded area is installed on ceiling where light from fixtures reaches directly.

• KIEAE Journal
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• v.10 no.1
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• pp.65-72
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• 2010

The use of natural light has the potential for improving both the energy efficiency and indoor environmental quality in buildings. A light-pipe system can introduce daylight to spaces that would otherwise not be able to benefit from the advantages of daylight penetration. For the light-pipe system to be widely used in Korea, it is important to quantify its daylighting performance with due consideration regarding the effects imposed by the local climate conditions. This paper presents the evaluation results of existing semi-empirical models to predict daylighting performance of a light-pipe system. The evaluation of the existing models was based on the monitoring data obtained from a underground parking lot in which the light-pipe system was installed. Comparisons were made between the predicted and the monitored data obtained from the study. The results indicated that semi-empirical models which was developed using the experimental data obtained under the Korean climatic conditions had a good prediction performance. We also quantified the effects caused by sky conditions, solar altitudes, room dimensions, and the aspect ratio of a light-pipe system on both the daylighting performance of the light-pipe system and the indoor illuminance distributions of the space using the semi-empirical model. Finally, this paper provides the design guideline of the light-pipe system for its application to an underground parking lot space.

• KIEAE Journal
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• v.3 no.2
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• pp.45-50
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• 2003

Today, there are increasing evidences that daylight is essential for health, well-being and productivity. One of the strong contributions, which atria can make to advantages in building, is in allowing the use of daylight. This research is to develop nomographs and to evaluate the daylight performances of toplit atria with louvers. For this purpose, the evaluation models of toplit atria with well indexes of 0.5, 1.0 or 2.0 have been selected through the field surveys of atrium buildings in Seoul area. Also, weather data for solar irradiance and luminous efficacy were gathered from the recently conducted previous researches. The computer simulations were performed under clear sky conditions, using the ADELINE program, and various daylight performances were analyzed by the daylight illumination ratio. Analyzing the simulation results, solar altitude, solar azimuth, and louver angle and louver reflectance were found to be important factors affecting the daylight performance of toplit atria. Using these variables, regression equations have been formulated, and the nomographs, which may predict the daylight performances of toplit atria with louvers, were developed. The developed nomographs were validated through comparing the results of nomograph predictions to the results of scale-model experiments.