Testing the use of daylight-linked control systems to address integrative lighting and energy savings in office buildings

Daylight-linked control systems (DLCSs) are used to maintain constant work plane illuminance and save energy. If properly calibrated, they could be used to guarantee circadian requirements fulfilment as well. In this study, the functioning of a closed-loop proportional dimming system is simulated based on on-field measurements. Simulations are performed calibrating the system to achieve different targets: three work plane task illuminances (300 lx, 500 lx, 750 lx) and one melanopic equivalent daylight illuminance (melEDI) value (250 lx) alternatively. Four electric light CCT profiles (stable at 3000 K, 4000 K, and 6500 K, and variable during the day) are considered. Results demonstrate that when the system is calibrated according to work plane illuminance, melEDI values are always fulfilled under clear sky and with overcast sky when task illuminance and CCT are high. When the system is calibrated to meet circadian requirements, the CCT choice is crucial to guarantee work plane illuminance.