• KIEAE Journal
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• 제6권2호
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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.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8901-8907
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• 2015

기존의 가로등은 배광특성 조절이 어려워 주변 환경 및 도로의 상황에 따라 빛을 고루 전달하지 못하므로, 눈부심, 농작물 결실저해 및 수면 방해 등의 광공해를 발생시키고 있는 실정이다. 본 논문에서는 이러한 문제를 해결하기 위해 주변 환경 및 도로 상황에 따라 조사되는 빛의 각도를 조절할 수 있는 새로운 구조의 LED 가로등 기구를 제안 하였다. 제안된 LED 가로등 기구는 반원구조의 형상을 갖는 각도 조절 장치를 이용하여 도로의 종류 및 특성에 따라 배광특성을 조절 할 수 있도록 하였다. 측정 및 모의실험결과 배광각도는 최소 $100^{\circ}$에서 최대 $154^{\circ}$까지 조절이 가능함을 확인하였고, 평균조도는 KS 규정의 15%를 초과하였으며, 종합 균제도는 KS 규정의 50% 이상을 초과하여 성능이 우수함을 확인할 수 있었다. 따라서 본 연구를 통하여 개발된 대용량 LED 가로등 기구는 광공해를 해소하고 광원 분포의 균제도 최적화와 눈부심을 최소화 할 수 있을 것으로 사료된다.

• 설비공학논문집
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• 제26권9호
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• pp.424-433
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• 2014

The purpose of this study is to evaluate the effectiveness in the lighting performance of mixed type light-shelf, by comparing and analyzing the internal light-shelf, external light-shelf, and mixed-type light-shelf. The performance of light-shelf was evaluated according to the angle of light-shelf at summer solstice, winter solstice, vernal equinox, and autumn equinox. The comparative analysis between the internal light-shelf, external light-shelf, and mixed-type light-shelf was carried out using the performance evaluation and analysis method. The result of performance evaluation is shown as follows. The mixed type light-shelf showed the highest lighting performance all at summer solstice, winter solstice, vernal equinox, and autumn equinox, followed by the external light-shelf and the internal light-shelf in the same order. The mixed type light-shelf was the most favorable for bringing daylight to indoors by adjusting the angle of light-shelf, and it also showed the highest lighting performance in terms of uniformity ratio of illumination which indicates the quality of light.

• 한국생활환경학회지
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• 제24권6호
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• pp.810-823
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• 2017

The envelope is important for sustainable building. Recent commercial buildings are causing thermal degradation and cooling load due to the increase of the area of the windows. Therefore, this research studied kinetic shading system which can improve energy saving and visual environment in summer. For that, this study proposed new shading system and shape considering the orientation of the building and the location of the sun. Based on this, this study analyzed the effectiveness on energy reduction and improvement of visual environment by applying the kinetic shading system proposed in this study. As the results of this study, energy reduction rate was 35% in the east, 22.9% in the south, and 30.7% in the west depending on the application location. Also, as the result of the illuminance analysis, it was found that the effect of achieving uniformity ratio of illumination was considerable.

• KIEAE Journal
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• 제16권5호
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• pp.57-64
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• 2016

Purpose: Recently, lighting energy consumption in buildings has been gradually increasing and more studies are being carried out in order to solve this problem. Especially, the efficiency of the light-shelf system, which is a natural lighting system, has been recognized as a potential solution in addressing this problem and so various studies regarding the light-shelf system are being conducted. However, if high luminance material is used for the light-shelf system, glaring may occur in certain circumstances even though such material increases efficiency, and there are also difficulties related to maintenance and management in the case of an external light-shelf system. Therefore, the purpose of this study is to suggest modifications in relation to the reflectivity of the light-shelf system and introduce a rolling type light-shelf system with built-in cleaning equipment. In addition, a performance evaluation technique was established to verify its effectiveness. Method: In this study, we reviewed previous studies related to the light-shelf system and its performance. Then a testbed was established to assess the performance of the rolling-type light-shelf system suggested in this study. Also, the performance of the rolling-type light-shelf system suggested in this study was compared and analyzed with that of existent light-shelf systems in order to better verify the performance, and the uniformity ratio of illumination and lighting energy consumption were calculated for this purpose. Result: The results of the performance evaluation are as follows. 1) The performance evaluation result of the light-shelf system on the day of the summer solstice shows that $30^{\circ}$ is appropriate for the angle of light-shelf system, and the depth of the incoming natural light also increases as the angle of the light shelf increases. 2) It is possible to improve the uniformity ratio of illumination by increasing the reflectivity of the light shelf, and the reason for this is the increase in the amount of incoming light entering indoors due to the increased reflectivity of the light shelf. 3) The rolling type light-shelf system suggested in this study enables energy saving in comparison with existent light-shelf systems, and when the external illuminance decreases to 60,000 lx and 40,000 lx during the summer solstice due to factors such as the weather, the suggested light-shelf system can save energy by 12.1% and 5.1% respectively. Thus the light-shelf system proposed in this study is deemed to be effective in reducing energy costs.

• 한국의학물리학회지:의학물리
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• 제18권2호
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• pp.98-106
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• 2007

2005년 6월 연세의료원 세브란스병원에서는 진단목적으로 20대의 5 mesa 화소 Totoku ME511L 평판 LCD 표시장치를 추가하여 PACS를 확장하였다. 20대의 Totoku ME511L 표시장치를 대상으로 반사, 휘도 반응, 휘도 공간 의존, 분해능, 잡음, 베일링 그레어, 그리고 색도 항목에 대하여 AAPM TG 18보고서에 기준하여 정량적인(또는 시각적인) 인수검사를 실시하였다. 측정에 사용된 장치는 색도를 측정할 수 있는 만원경식 휘도계, 조도계, 반사 측정에 필요한 빛 선원, 빛 차단 장치, 그리고 TG18 테스트 패턴들이었다. 선택된 8대의 표시장치에 대한 평균 확산 반사계수($R_d$)는 $0.019{\pm}0.02sr^{-1}$이었다. 휘도 반응 검사에서, 휘도비(LR), 최대 휘도 변이($L_{max}$), 그리고 최대 대조도 반응 변이는 각각 $550{\pm}100,\;2.0{\pm}1.9%$, 그리고 $5.8{\pm}1.8%$이었다. 휘도 균일도 검사에서, 최대 휘도 변이는 TG18-UNL10 테스트 패턴의 10% 휘도에 대하여 $14.3{\pm}5.5%$이었다. 분해능 측정은 휘도 측정법으로 수행하였으며 중심에서 퍼센트 휘도(${\Dalta}L$)는 $0.94{\pm}0.64%$이었다. 시각적인 방법의 잡음측정의 모든 경우에서, 중앙 및 주위 4사분면에서 가장 작은 것을 제외하고 15개의 모든 정사각형의 표적을 인식할 수 있었다. 글레어 비(GR)은 $12,346{\pm}1,995$이었다. 최대 색도 균일도 지표(D)는 $0.0025{\pm}0.0008$이었다. 또한 국내 실정에 적합한 진단용 표시장치의 정도관리 가이드라인 연구 결과를 제시하였다. 모든 인수검사 결과는 AAPM TG18 보고서 기준에 포함되어 진단 목적으로 사용하기에 적합하였다. 결론으로 인수검사는 표시장치가 진단에 사용하기에 적합한 성능임을 알려줄 뿐만 아니라 정도관리의 가이드라인, 최적 판독 환경, 그리고 표시장치의 교체시기를 결정하여주는 중요한 역할을 할 수 있다.