Energy Saving Generated Through Automatic Lighting Control Systems According to the Estimation Method of the Standard EN 15193-1

The standard EN 15193-1:2017 “Energy performance of buildings - Energy requirements for lighting” introduced a detailed method to calculate the energy demand for lighting in buildings. The method contains a calculation of the daylight supply, which accounts for the impact of lighting control systems, both daylight-linked and occupancy-based. This paper presents the results of a study carried out to quantify, with respect to a manual on/off switch, the energy savings due to the four typologies of daylight-linked controls included in the standards, as well as their combination with an occupancy auto off control. To highlight the factors that affect the amount of saved electric energy, several spaces were considered, with different daylight availability, windows orientation and shading system, located in sites at different latitudes and climate conditions, and considering two types of building: offices and classrooms. A database of 2880 cases was built. As a second step of the study, for each site and type of control, the minimum window-to-wall ratio necessary to obtain a pre-defined saving was calculated. The results show for what combinations of variables two target savings of 20% and of 30% can be reached using the photodimming and occupancy controls contained in the standard.