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A Study on Prediction Method of Sky Luminance Distributions for CIE Overcast Sky and CIE Clear Sky

CIE 표준 담천공과 청천공 모델의 천공 휘도분포 예측 방법에 관한 연구

  • Kim, Chul-Ho (Department of Architecture, Graduate School, Korea University) ;
  • Kim, Kang-Soo (Department of Architecture, Korea University)
  • 김철호 (고려대학교 대학원 건축학과) ;
  • 김강수 (고려대학교 건축학과)
  • Received : 2016.01.25
  • Accepted : 2016.04.20
  • Published : 2016.06.30

Abstract

Daylight is an important factor which influences building energy efficiency and visual comfort for occupants. It is important to predict precise sky luminance at the early stages of design to reduce light energy in the building. This study predicted sky luminance distributions of standard sky model(CIE overcast sky, CIE clear sky) that was provided from the CIE(Commission internationale de $l^{\prime}{\acute{e}}clairage$). Afterward, result of sky luminance was compared and verified with simulation value of Radiance program. From the CIE overcast sky, zenith and horizon ratio is about 3:1. From the CIE clear sky, luminance value gets most high value around the sun. On the other hand, luminance value is the lowest in the opposite direction of the sun when angle is $90^{\circ}$ between the sun and sky element. As a result of comparing the calculation results with Radiance program, sky luminance prediction error rate is 0.4~1.3% when it is CIE overcast sky. Also, sky luminance prediction error rate is 0.3~1.5% when it is CIE clear sky. When compared with the results of radiance simulation, it was evaluated as fairly accurate.

Keywords

References

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Cited by

  1. Development of Sky Luminance and Daylight Illuminance Prediction Methods for Lighting Energy Saving in Office Buildings vol.12, pp.4, 2019, https://doi.org/10.3390/en12040592