• Land and Housing Review
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• v.10 no.3
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• pp.33-41
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• 2019

This study examines the distributions of daylight illuminance in a small office space under clear and cloudy sky conditions. Three shading conditions using Venetian blinds were applied for the analysis of daylight illuminance. Computer simulations using the Lightscacpe were conducted for the daylight conditions applied to the office space. Results indicate that the illuminance differences between clear and cloudy sky for south-facing conditions were greater than those for north-facing conditions. The differences in December and June were the greatest and smallest, respectively. For the north-facing conditions, the daylight illuminance at 10:00, 12:00 and 14:00 in June and September under the cloudy sky was higher than those under the clear sky conditions. For all daylight conditions, the biggest amount of illuminance reduction occurred when the shading device conditions were changed from the no blind to the 45 degree blinds. As the distance from window increased, the shading effect that occurred when the shading device conditions were changed from the horizontal blind to the 45 degree blinds increased.

• Land and Housing Review
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• v.12 no.2
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• pp.79-89
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• 2021

This simulation based study analyzed the horizontal daylight distribution on the floor and ceiling of a small office space based on window orientations and interior window blind positions. South and north facing windows were each tested without window blinds and with window blinds at 45° and 180° (horizontal). The study showed that the illuminance value was highest 1m from the window. On the floor and ceiling, the difference in illuminance value was the greatest and least in December and June, respectively. The indoor illuminance value was highest when there was no window blind and under south-facing conditions. The greatest illuminance difference occurred between window blinds positioned at 45° and 180°. Under north-facing conditions, windows without blinds or with blinds at 45° had the least impact on indoor illuminance with illuminance being more evenly distributed.

• 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.

• Electric Engineers Magazine
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• v.228 no.8
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• pp.58-63
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• 2001

낮시간에 창이 있는 장소에서는 주광의 입사로 제법 높은 조도가 얻어지면 그의 정도는 기상조건이나 건물 및 창의 구조, 실내조건 등에 따라서도 변화한다. 따라서 변화하는 외광의 밝음을 실내에 설치된 주광센서로 검지하여 창가에 있는 일정범위내의 조명기구를 자동적으로 점멸 제어하여 전력절감을 도모하는 것이다.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.35-43
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• 2004

Illuminance and luminous levels in a small office space due to daylight were calculated to analyze the impact of daylight on contrast and lighting energy savings. Computer simulations were performed for four blind conditions under a clear sky condition. The blind conditions significantly impacted the illuminance an4 luminance level. Visual performance scores were calculated according to the transfer function that uses absolute contrast between target and background surface. The blind condition that had 45 tilted angle toward ground provided good contrast and performance scores. Using a control algorithm of an automated daylight dimming control system lighting energy sayings were predicted. For all blind conditions minimum lighting energy was consumed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.3
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• pp.231-242
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• 2011

This study examines influences of a daylight dimming control system on the variation of indoor illuminance and lighting energy savings in a small office space. Field measurements and a series of computation were performed for typical types of sky conditions in summer. Results indicate that the daylight illuminance under clear and partly-cloudy sky were close to the target illuminance during a majority of time due to a higher ratio of window to wall. However, the target illuminance was not kept successfully due to the variation of photosensor signals which were strongly influenced by desktop illuminance. The system with partially-shielded conditions succeeded to keep target illuminance under clear sky conditions. The system failed under overcast sky conditions since the electric light output from fixtures caused excessive signals to photosensors due to insufficient daylight on a desktop. Unshielded and fully-shielded conditions were not recommended for effective controls of the systems. The influence of lighting fixtures on photosensors should be minimized to achieve successful lighting controls by daylight dimming systems.

• Solar Energy
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• v.11 no.1
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• pp.3-15
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• 1991

In this study global radiation and global illumination are directly measured and diffuse radiation and diffuse illumination measured utilizing semi-circular shadow ring. By analyzing measured radiation data, clear and overcast sky are classified according to the sky classification method used in Mantes, France. Measured illumination data are analyzed and 1) Clear sky illumination on a horizontal surface as a function of solar altitude. 2) Overcast sky illumination on a horizontal surface as a function of solar altitude, 3) Monthly variation of illumination. 4) Cumulative percentage of illumination, 5) Daylight intensity as a function of hours in a typical day, 6) Average number hours per day of illumination above 10 and 20klx are presented as a climatic data for daylighting design for Seoul, Korea.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.8-15
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• 2006

To reduce costs and address other practical concern related to architectural lighting, we have been involved in various aspects of advanced daylighting design and control. If we look toward future building trends, we see that the advanced has already successfully deployed such complex lighting control systems. This paper takes a broad view of what advanced manufacturers have done to develop energy efficient lighting control technologies such as sensors, lumen maintenance, time of day scheduling, peak demand reduction and so forth. First of all strategies, daylighting controls would also need to be commissioned to respond to the specific daylighting signature of the zone. To translate the daylight in term of the amount of energy savings, an electric lighting system is designed and automatic on-off control system integrated with the contribution of daylighting has been applied to the operating of the artificial lighting. The lighting analysis program, Lumen-Micro predicts the optimal layout of conventional fluorescent and incandescent lighting fixtures to meet the designed lighting level and calculates unit power density, which translates the demanded amount of lighting energy.