• 한국태양에너지학회 논문집
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• 제28권6호
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• pp.78-86
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• 2008

The aim of this paper is to show the daylight environment of a light pipe system according to sun movement. A light pipe system has been mounted on the roof of the windowless full scale model: the solar spot has diameter of 0.65m and is 1.3m long, giving an aspect ratio of 1:2. The full scale model was installed on the rooftop of the SHINAN apartment in Yongin city that has no obstructions against sunlight. The test room is equipped with sensors for the measurements of the internal illuminance and has an area of 6m(W)$\times$6m(D)$\times$4m(H). The system has been monitored with a data-logger to evaluate the cumulative distribution of illuminance on a floor-plane from 16th, April to 29th, May, 2008 over one month and selected clear sky condition. For the daylight performance of floor area, the totally 49 measuring points has been used to determine the internal illuminance and an HP datalogger(HP34970A) records the measurements for one consecutive month. The horizontal external illuminance has been measured with two outdoor sensors. This paper presents the results of monitoring light pipe system with internal/external illuminance ratio and cumulative frequency distribution of floor-plane illuminance are discussed The results show that lightpipe is proficient device for introducing daylight into the building. However It provided different daylight indoor environment with wide or narrow Interquatile range of illuminance, internal/external illuminance ratio and cumulative frequency distribution according to solar positions under suuny sky condition. For more achieving the improvement of lightpipes also include energy savings, user visual comfort with various indicators; seasonal solar height, room and lightpipes geometries.

• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.93-100
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• 2005

Character and illuminance distribution of daylighting is very important for the architectural plan in museum. Those data show bases for exhibition space design with daylighting and play a decisive role in visual perception of articles and space aesthetic. The goal of this paper was therefore to analyze the illuminance distribution in fine art museum with 3 typical girdle skylight types which are devided according to the art of protection from glare. This Experiment proved that they had a striking contrast with regard to the ratio of daylight illumination and illuminance distribution in spite of the same purpose of those development. The girdle skylight with a translucent glass showed the strongest value of the ratio of daylight illumination, but inequable illuminance distribution in space, excepting the area of the wall. However, the latticed reflector of light refracted daylight in the direction of wall and made illuminance distribution very equable in whole space. The ratio of daylight illumination at the girdle skylight which was located at the verge of the ceiling, was highest at the upper part of the wall and was reduced gradually from there, by way of the middle and under part of the wall, to the center of space.

• 설비공학논문집
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• 제22권11호
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• pp.788-797
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• 2010

This study examines the influence of fluctuating daylight illuminance on daylight dimming control systems. Field measurements were performed for a full-scale mocked-up model under various daylight conditions in winter. Fluctuating ranges for a partially-shielded photosensor were great when the variation of sky ratio was great. When solar altitude was lower the illuminance and fluctuating range of illuminance were great due to the influence of direct components of daylight and the interrefelction between surfaces in rear area of space. It implies that daylight dimming system would not function effectively, unless the desktop illuminance by daylight is enough. Fluctuation ranges of photosensor illuminance were lower than 50 lx under clear sky conditions, but they were greater than 100 lx under partly-cloudy sky conditions. It means that the fluctuation range of electric light output of lighting fixture would greater under the partly-cloudy conditions and cause potential visual annoyance to occupants. Outdoor vertical illuminance reaching the windows would be an effective factor that can be used to predict the fluctuation of photosensor signals for effective controls of daylight dimming system.

• 한국태양에너지학회 논문집
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• 제40권1호
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• pp.35-47
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• 2020

Due to the large window area, the lighting environment of the educational space between the window and deep part of the room is not uniformly illuminated, and the phenomenon of glare is severe. For this reason, the daylight performance of DSC-BIPV windows was analyzed in order to improve the natural lighting in the educational sector. The method derives the correlation with natural lighting by measurement and simulation. Dynamic simulation confirmed that the average illuminance of the target space was higher at later than the early afternoon. The performance of natural lighting at 40% and 30% transmission of DSC has the effect of significantly reducing the amount of excess light in existing windows. Nevertheless, the actual average illuminance in all seasons corresponds to the standard illuminance of the educational facility, 300 Lux. In addition, the uniformity is also seen through the skylight illuminance ratio.

• 조명전기설비학회논문지
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• 제27권12호
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• pp.54-62
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• 2013

In this study, a mock powder room was installed with variable LED lighting environments in order to conduct the experiments. The experimental conditions include luminaire type, illuminance ratio, vertical illuminance and color temperatures. The evaluation methods used were the Semantic Differential Method and a subjective evaluation on activities through observation. The SD evaluation result factor analysis categorizes ideas into three factors: brightness, emotion, and glare. The vertical bracket or the combined luminaire (luminous panel+ Vertical bracket) has better brightness than luminous panel. A vertical illuminance of 500lx is not significantly difference as compared to 600lx, allowing 500lx to be considered standard. The emotional atmosphere is evaluated as being better at lower color temperature. The luminous panel is the best for reducing glare while the vertical bracket is the worst. The best conditions differ according to the illuminance ratio of the luminous panel and vertical bracket. In the subjective evaluation (satisfaction with lighting environment, suitability to activity) the combined luminaire and 4000K received the best evaluation.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.60-65
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• 2019

In this paper, the hybrid illumination system for effectively detecting surface defects in steel plate with lowcontrast, non-uniformity and featureless is designed based on illuminance uniformity. First of all, characteristics of steel plate defects were considered and typical inspection illumination system is implemented. Optimum illumination parameters for uniformly illuminating an inspection area in the typical illumination system are selected based on the illuminance uniformity and illuminance distribution measurement. The illuminance uniformity and illuminance distribution are measured using an illuminometer based on the arduino. Through illuminance distribution analysis of the typical illumination, an hybrid illumination is designed by fusing bi-directional illumination and coaxial illumination. The hybrid illumination showed higher uniformity ratio and illuminance distribution than the typical illuminations. The hybrid illumination system showed the ability to uniformly illuminate the entire inspection region of steel plate surface.

• 설비공학논문집
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• 제24권5호
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• pp.433-442
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• 2012

The influence of outdoor sky conditions on photosensor signals were examined to determine an appropriate index that is effectively used for optimum illuminance fluctuation when a daylight dimming system is used for a small office. Field measurements were conducted under various sky conditions. Results indicate that the outdoor global and vertical illuminance fluctuated within narrow ranges under clear and overcast sky conditions. The fluctuation of sky ratio under partly-cloudy sky caused wide ranges of illumnance fluctuation. A partially-shielded photosensor at backwall produced 56% of light output from fixtures controlled by a photosensor at ceiling. This implies that the photosensor at backwall does not always guarantee target illuminance due to the less output. The fluctuation of light output from fixtures were insignificant under clear and overcast sky. The fluctuation range of photosensor illuminance under partly-cloudy sky caused wide fluctuation ranges of light output. Regression result implies that the outdoor vertical illuminance was recommended for an effective index that is used for control of light output.

• Transactions on Electrical and Electronic Materials
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• 제13권1호
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• pp.16-18
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• 2012

LED lighting systems that combine lighting capability, emotional and physiological characteristics are required for lighting source and multifunctional applications. In this work, Simulation studies using optical analysis software packages, Light Tools, are presented. This is done to estimate the uniformity ratio of illuminance and photosynthetic photon flux density (PPFD) of the periodic 2D lattice arrangements, such as square, diamond, two-way bias quadrangular, hexagonal, and Kagome lattices, under the same transmissivity, absorptance and reflectivity. It has been found out that the two-dimensional Kagome lattice arrangement exhibited high uniformity ratio of illuminance and PPFD compared to other lattices. Accordingly, these results can be used to guide a design and improve the lighting environment which in turn would maximize the uniform distributions of illuminance.

• 한국환경생태학회지
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• 제29권3호
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• pp.441-453
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• 2015

본 연구에서는 서울 도심 내 야간 인공 조명의 조도에 따라 수목 개화율과 잎 생장률이 차이가 있는 지를 규명하기 위한 사례 연구로 수행되었다. 조도는 총 26개소에서 78개 지점에서 측정하였고, 조도와 토지이용현황을 고려하여 3개 그룹으로 구분하였으며, 그룹 A(조사구 1~7)의 조도 범위는 4.90~112.50 lx, 그룹 B(조사구 8~18)의 조도 범위는 0.45~42.40 lx, 그룹 C(조사구 19~26)의 조도 범위는 0.28~22.10 lx이었다. 조도 차이 일원배치 분산분석 결과 그룹 A, B, C로 분류되었다. 수목 개화율은 왕벚나무와 철쭉류 각 30개체, 수목 잎 생장률은 느티나무, 은행나무, 단풍나무 각 30개체를 선정하여 조사하였다. 수종별 일원배치 분산분석 결과 연구대상 수목 중에서 개화율은 철쭉류, 잎 생장률은 단풍나무가 세 개의 그룹으로 분리되어 상대적으로 조도 차이에 따른 수목 영향 지표종으로서 유용한 것으로 판단되었다. 그룹별 평균 조도와 수목의 개화율 및 잎 생장률 간 상관관계 분석결과 유의성이 인정되어 조도가 높을수록 수목의 개화 및 잎 생장이 빨라지는 경향이 있는 것으로 판단되었다. 향후에는 야간 조명의 빛공해 수준별로 수목에 어느 정도 영향을 미치고 있는 지에 대한 보다 구체적인 연구가 이루어져야 할 것이다.

• KIEAE Journal
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• 제8권1호
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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.