Selection of spatial sensitivity curve and installation location of photosensors for daylight-linked control systems in space with dynamic shading devices

Daylight harvesting and daylight-linked control systems (DLCSs) are important building design strategies that maximize daylight usage and save energy. Proper setup of DLCSs, which use photosensor signals to control electric lighting and shading devices, can be challenging. Despite previous efforts to find an optimal layout, locations, and spatial sensitivity curve of photosensors, there are inconsistencies in the findings, and the presence of dynamic shading systems has not been fully addressed. Annual daylight simulations are used to study the impact of the spatial sensitivity curves and installation locations of photosensors for spaces with dynamic shades. This study also provides recommendations for sensor selection, installation, and commissioning. The results show that shading systems cause significant discrepancies in the ceiling-to-task illuminance relationship but restricting the sensor field of view (FOV) can minimize the discrepancies. Cosine-curve photosensors with narrower FOV are capable of predicting task illuminance directly below the sensor and the illuminance of other parts of the space. Light deficit and light waste of the DLCS are strongly affected by ceiling-to-task ratios picked, especially when using photosensors with a low coefficient of determination of ceiling-to-task illuminance. Keeping shades at a low position is recommended when commissioning to avoid a light deficit. •Dynamic shading devices strongly affect the performance of photosensors.•Sensor's spatial sensitivity curve is key of its predicting performance.•View of the window should be considered when choosing installation locations.•Proper selection of task-ceiling ratio could minimize light deficit or light waste.•Keeping shades at a low position is recommended when commissioning.