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CIE 2016 "Lighting Quality and Energy Efficiency"

Updated: Apr 20, 2021

IEN has been invited to present the paper:

Discomfort Glare in Energy Efficient Buildings: A Case Study in the Malaysian Context

Discomfort glare is a well known problem within the built environment. However very little research has been conducted on discomfort glare in purely tropical environments. This preliminary investigation focussed on the ST Diamond Building located in Putrajaya, Malaysia. In total, 68 surveys were collected during the investigation. The surveys consisted of a questionnaire as well as luminance mapping of the occupant’s visual environment.

Luminance maps were analysed via Evalglare to calculate the Daylight Glare Probability(DGP) and Unified Glare Probability (UGP). It was discovered that occupants were more tolerant to potential glare than expected, most likely due to the high luminance uniformity from innovative daylighting strategies employed in the building. Occupant position in relation to the window had a significant effect on both glare indices tested. The UGP was much better at predicting glare for occupants further away from the façade.

Type 2 (or false-negative) analysis was conducted on both glare indices. A false-negative result occurs when the survey response was “uncomfortable” but the index being tested predicted “comfortable”. The method showed promising results for UGP in the case of the ST Diamond Building, with an index threshold of 0.35 required to achieve 95% accuracy in predicted comfort. The DGP required an index threshold of 0.07, which may be impractical to implement in lighting design.

The paper is available here:

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