Daylight utilisation in perimeter office rooms at high latitudes: Investigation by computer simulation

A simulation study of daylight autonomy in perimeter office rooms at high latitudes is presented where the following variables are studied: Glazing-to-wall ratios (GWR), climate, orientation, inner surface reflectance, glazing visual transmittance, Venetian blind management and electric lighting dimming and switching systems. Based on daylight utilisation alone, the results indicate an optimal GWR ranging between 20% and 40%, with a North orientation requiring a larger GWR (40%), a South orientation a smaller GWR (20%) and an East/West orientation an intermediate GWR (30%). The reflectance of inner surfaces has a significant effect on daylight autonomy and the use of low transmittance glazing demands a larger GWR (60%) to achieve the same daylight autonomy as 20% GWR with high transmittance glazing. Also, the results indicate that the choice of electric lighting dimming and switching systems has a more significant impact on electricity use than the GWR, orientation and the other variables examined.