QC-06-005 - Validation of Skylight Performance Assessment Software PDF

This paper presents a comparison study between the simulations of SkyVision and measurements made in a scale model. SkyVision is a computer tool used to calculate the overall optical characteristics, indoor daylight availability, and energysaving potential of projecting and tubular skylights. The measurements included the overall visible transmittance and indoor daylight illuminance of the skylight. A rectangular wooden box was used as a scale model of a simple commercial building. The top surface of the box was fitted with a curbed opening to accommodate the skylights to be tested. Seven skylight shapes were tested: two circular dome models, one with clear and one with white acrylic glazing; two rectangular bubble dome models, one with clear and one with white acrylic glazing; one clear acrylic hexagonal pyramid model; one clear polycarbonate barrel vault model; and one tubular skylight model. The measurements were conducted for a whole day, thereby covering different sky conditions: overcast, partly cloudy, and clear sunny skies. SkyVision’s simulations for the skylight transmittance compared reasonably well with the actual measurements, except for the hexagonal pyramidal skylight. The hexagonal pyramid surface exhibited some lens effects around the surface vertices, which were not possible to model in SkyVision. As for the skylight indoor illuminance comparison, the SkyVision’s simulations were in good agreement with the actual measurements for all occurrences of sky conditions.