• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
• /
• pp.457-462
• /
• 2012

Daylighting software is an important component to predict the performance of daylighting system in advance of a field demonstration study with installing them in buildings. PHOTOPIA is a powerful software to generate a candela distribution curve(CDC) of an active daylighting system like a tracking dish concentrator. With PHOTOPIA, a set of candela distribution curves was generated under clear sky conditions and different solar altitude angles. The candela distribution curves were then imported to RADIANCE for rendering and analysis on the daylighting performance of a tracking dish concentrator when it installed in a actual class room without windows. As a result, the daylight collection efficiency of the dish concentrator was 68.4% when we assumed that there was no tracking error. It was found that candela(cd) and total lumens(lm) increased with solar altitude rising, whereas the distribution angle was fixed. The illuminance uniformity on the work plane in the class room was relatively low, 0.12, while the illuminance uniformity on the area of $2.7m^2$ to which the light was illuminated was considerably high, 0.60. The maximum illuminance was 1,340lux with a solar altitude angle of 80 degrees.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
• /
• pp.298-299
• /
• 2009

Use of a DLP-beam projector is proposed to measure solar cell quantum efficiency distribution. The measurement requires a good spatial uniformity of the beam from the projector. We measured the spectral power distribution of the beam projector and the spatial uniformity of the white beam. By changing the gray level of the white beam at the measured spatial points, we improved the spatial illuminance uniformity to be about 2 % which was otherwise as much as 400 %.

• 한국조명전기설비학회지:조명전기설비
• /
• 제6권2호
• /
• pp.37-42
• /
• 1992

In this paper, illuminance distribution is calculated by the Monte Carlo simulation. In comparison with other methods, it has simpler arithmetic process. Light is assumed to be of particle nature. It has particular direction taken from a random function. Paths of each particle are calculated, and the final absorbing points are found. repeating this process, the statistical illluminance distribution is determined proportional to the number of particles striking each wall. For a better result and graphic output, each wall surface was divided into many small ones.

• 한국태양에너지학회 논문집
• /
• 제32권3호
• /
• pp.104-113
• /
• 2012

A set of candela distribution curves(CDCs) were generated for a fiber optic dish daylighting system by Photopia under clear sky conditions at different solar altitudes. The candela distribution curves were then exported to Radiance for photometric analysis of a windowless lecture room. Observations were made on the Radiance rendered illuminance images, which provided photo realistic scenes varying with solar altitudes. If no tracking error were assumed, the daylight collection efficiency of the system remained at a constant value of 68.4% during its operation. Higher the solar altitude angle, greater in photometric quantities were observed, which are represented by candela(cd) and total lumens(lm). In all cases considered, however, the angle of light distribution remained fixed reflecting the solar tracking feature of the system. The illuminance uniformity on the workplane lingered around 0.12, which is quite low. This is quite a contrast to its average value of 0.68 of the $2.7m^2$ area directly below the terminal device (diffuser) of the system. The maximum illuminance of 1,340lux was obtained at a solar altitude of 80 degrees.

• 한국조명전기설비학회지:조명전기설비
• /
• 제10권6호
• /
• pp.48-53
• /
• 1996

본 연구는 인천시에 소재한 초·중·고등학교의 야간 조명환경(교실, 과학실, 실험실)을 조사하기 위하여 개교된지 10년이내, 20년, 30년 경과 등으로 나누어 각 4개 학교 이상을 추출하여 조도를 측정, 분석하였다. 교실 평균조도는 235.5[lx](고등학교 ; 260[lx], 중학교; 208[lx], 초등학교 ; 203[lx]), 과학실과 실험실의 경우에는 233.7[lx](고등학교 ; 248.8[lx], 중학교; 216.4[lx], 초등학교 ; 207.8[lx])로서 양적인 면에서는 매우 향상되었으나, 균제도(평균값이 교실은 0.95, 과학실이나 실험실은 1.08)에 있어서는 권장값을 매우 초과하고 있으며, 조도구배에서도 최대조도와 최소조도의 비(교실;7.9, 과학실이나 실험실;6.8)가 크게 나타나며, 건축된지 오래된 학교일수록 크게 나타나 조도의 질적인 개선을 위한 많은 노력이 필요한 것으로 나타났다.

• 한국정보통신학회논문지
• /
• 제21권1호
• /
• pp.157-164
• /
• 2017

본 연구는 균일한 조명을 얻기 위해 중첩 조명 모델(overlapped illumination model)을 사용하여 자유 형상 렌즈(freeform lens)를 제작하였으며, 제작한 LED 렌즈들의 특성을 비교 분석하였다. 제작한 렌즈는 LED 광원의 위치변화, 두께 및 기울임을 이용해 성능을 평가하였다. 아울러 조명영역은 평균 조도 (average illuminance)와 조도 균일도 (illuminance uniformity) 변화 값으로 측정하였다. 광도 분포의 Z축 방향변화에 대해서는 중첩 모델과 발산 모델이 대체로 비슷한 공차 특성을 보였으나, 렌즈두께 변화에 대해서는 중첩모델이 발산모델에 비해 조도 균일도 공차 특성은 현저히 개선됨을 확인하였다. 또한, 발산 조명 모델로 설계된 렌즈가 전반적으로 좋은 성능을 나타냈으나, LED 방출에 대한 성능은 중첩 모델에서 그 편차의 폭이 상대적으로 적게 나타났다.

• KIEAE Journal
• /
• 제15권5호
• /
• pp.107-112
• /
• 2015

Purpose: This study desires to investigate an effect of indoor temperature, humidity, and illuminance targeting a planting system of double-skin facade and cavity space adjacent to the outside within a certain period of winter. Through this, the study suggests a basic material about an energy conservation effect of double window system using planting to reduce heating load of a building in winter, so desires to contribute to indoor thermal comfort effect and illuminance correction study of double window and indoor plant. Method: Considering effects such as day and night climatic elements and air conditions in winter, illuminance measurement was conducted through a double-skin facade of space, a subject of the measurement, on the basis of practical residence time of a resident, and this study analyzed characteristics of indoor illuminance about this. The study measured and compared a change of insolation, dry-bulb temperature, and relative humidity at each indoor-outdoor measuring point, so measured and compared characteristics of an indoor temperature effect by elements of double-skin facade and indoor plant. Result: Through this study, the researcher could determine that indoor plant within double window in winter not only blocks solar radiation but also photosynthesizes, so is somewhat disadvantageous to winter thermal comfort reducing heating load. In addition, solar radiation going through interior plays a role to bring down somewhat high humidity to about 50% of reasonable humidity, so plays a direct role of maintenance of comfortable indoor space. Although there are effects such as blocking of solar radiation and temperature reduction, this has a positive influence on humidity control and proper illuminance distribution. The researcher could determine that illuminance, temperature, and humidity by solar radiation penetration for the whole measuring time play a role to supplement indoor environment mutually.

• KIEAE Journal
• /
• 제8권3호
• /
• pp.101-106
• /
• 2008

The use of daylighting has been increased recently due to energy and visual comfort. The aims of interior daylighting are to adequately illuminate visual tasks, to create an attractive visual environment, and to save electrical energy. Lightpipe can improve the distribution of light to interior spaces. This study aims to evaluate the comparative daylighting performance of lightpipe under different sky conditions with mock-up model, sized $6m{\times}6m{\times}4m$ ($w{\times}d{\times}h$). For the purpose, perpendicular lightpipe system was designed as 650 diameter, with an aspect ratio of 2. Totally 49 measuring points of and two of outdoor illuminance on the horizontal plane were monitored from 09:00 to 18:30 on April 29 and May 15 2008. Agilent data logger and photometric sensor were used. Light factor were used to analyse daylight performance under different sky condition. Under overcast sky condition and clear sky condition, the lightpipe system is suitable for KS recommendation level of illuminance.

• 한국조명전기설비학회지:조명전기설비
• /
• 제13권2호
• /
• pp.133-133
• /
• 1999

Average illuminance and luminance can be calculated by graphical methods to a certain extent but to calculate for a wide place a suitable software is needed. Softwares suitable for this purpose have been already developed in foreign nations, but the appropriate softwares for domestic use have not been developed. Therefore a program is developed which is executable in Hangul Windows. The softwares LAPRoad, is developed to calculate luminance and illuminance distribution of road surface, as well as average luminance and illuminance, overall uniformity, longitudinal uniformity, threshold increment veilling luminance and glare. And an apparatus that measures road surface reflection properties is developed. Because the road surface reflection properties is very important in luminance calculation, then concrete road surface reflection properties were measured.

• 조명전기설비학회논문지
• /
• 제22권1호
• /
• pp.17-23
• /
• 2008

본 논문에서는 2분할 수광 방식의 측정시스템을 이용하여 수도권 일대의 도로의 조도와 휘도분포를 측정하여 국내 도로조명 실태를 파악함으로써 조명시설들의 특징에 대하여 분석했다. 측정결과 대다수의 도로가 도로의 형태, 조명기구의 점등방식, 도로주변의 가로수 혹은 장애물 등의 영향으로 도로조명 허용기준을 만족시키지 못하고 있었다.