... and the things to consider when installing skylights on warehouses to bring in daylight.

Lighting is responsible for 80 % of the electrical consumption in a warehouse. Starting from the vantage point that the cheapest energy is energy which is not consumed, a think tank analysed daylight distribution in an Optima warehouse designed by GSE.

		Analysis:
		In order to quantify the contribution of daylight, and to highlight the possibilities of using daylight, digital simulations of natural daylight were performed on a 3D CAD model which took several criteria into account, including the different geographical zones where the building could be built, times of year, and, inside the warehouse, the storage zone and the loading/unloading zone. The distinction must be made between two different zones in a standard 6,000-m² cell: The storage zone equipped with racks which accounts for 4,800 m².  The shipping/receiving zone with 1,200-m² free space. In the storage area, even if the daylight is created just above the aisles, the actual light distribution is very heterogeneous due to the racks which project areas of shadow. This shadow requires the addition of electric lighting, even during the day. In the shipping/receiving zone, the situation is different. Natural daylight is well distributed and electric lighting can be totally done away with during the entire day. FLJ (average daylight factor) Intensity of illumination at measured point in lux (in the warehouse)        -------------------------------------------  = FLJ = daylight factor in % Intensity of illumination at open point in lux (on the roof)

		GSE proposes a new approach
		Based on these results, GSE proposes the following approach: In the storage areas, natural daylight is limited to the installation of the skylights required for smoke removal purposes. Lighting is thus provided by targeted electrical lighting in the aisles. A provision such as Ecolight, or a system which lights only the aisles being used would sharply reduce electricity costs.  However, in the shipping/receiving areas, use both smoke removal skylights and daylight-providing skylights. The skylights will be distributed so as to ensure entirely natural, uniform daylight throughout the entire daytime period, thus providing high user comfort and zero energy cost.