Paper Conference

Proceedings of BSO Conference 2022: 6th Conference of IBPSA-England


Comparative analysis of daylight levels in an office space considering standard overcast sky condition and measured CIE sky type of Gurugram, India

Rohit Thakur 1, Riya Malhotra 1, Ankit Bhalla 2, Sanjay Seth 1
1 The Energy and Resources Institute
2 GRIHA Council

Abstract: The climatological study of sky conditions and radiation is relatively new in India. Prediction of daylight availability in an interior space throughout the year is imperative for daylighting design. This prediction of daylight availability is made in absolute or relative terms to external illuminance. This paper aims to showcase the correlation analysis of the measured CIE sky and overcast Sky for equinox days; March 21 and September 21. VELUX daylight visualizer software were used to run a box model analysis to extract illuminance levels for a correlation study of observed CIE sky conditions with overcast sky conditions. From the correlation analysis of the simulated data, it is computed that the illuminance analysis perceived by daylight simulation considering measured sky conditions compared to overcast sky conditions on the analysis grid is 23% more accurate in March and 42% more accurate in September. Therefore, it can be affirmed that the computed set of CIE design skies shall be used to enhance the passive design of windows for the locations falling under the respective climatic zones for better cost optimization through accurate illuminance prediction.
Keywords: Sky Modeling, CIE standard Sky, Daylighting, VELUX daylight visualizer, illuminance