Shading device
A shading device is configured to be integrated into a façade of a building. The shading device includes an imaging system configured to create images of an outside view of the building.
1. Shading device configured to be integrated on a facade of a building wherein the shading device comprises an imaging system configured to exclusively create images of an outside view of the building, wherein the imaging system is integrated with the shading device, wherein the outside view comprises a sky portion and a landscape portion, and the imaging system comprises a lens and a processor,
wherein the imaging system is configured to
determine a directional luminance distribution of the outside view comprising the sky portion and the landscape portion from the images of the outside view comprising the sky portion and the landscape portion;
compute a work-plane illuminance for a target work-plane inside a target room behind the shading device, at each position or state of the shading device, exclusively from the determined directional luminance distribution by making use of a pre-defined model of a target building and quantified light transmission behavior of the shading device, wherein the target work-plane is out of the field of view of the imaging system;
evaluate a glare risk for occupants inside the target room; and
determine an optimal position or state of the shading device which provides an optimal trade-off between work-plane illuminance and glare risk.
2. Shading device according to claim 1 , wherein the shading device comprises a blind, wherein the blind is a Venetian blind or a vertical blind that comprises a multitude of slats, and the imaging system is configured to determine an optimal inclination angle or vertical position of the slats.
3. Shading device according to claim 2 , wherein the shading device comprises a DC motor, wherein the DC motor is configured to tilt the slats of the Venetian blind around respective longitudinal axes of the slats, wherein the DC motor is configured to reach a tilt angle resolution of 10 degrees or less.
4. Shading device according to claim 3 , wherein the DC motor is configured to reach a tilt angle resolution of 5 degrees or less.
5. Shading device according to claim 3 , wherein the DC motor is configured to reach a tilt angle resolution of 3 degrees or less.
6. Shading device according to claim 2 , wherein the shading device comprises a reduction gearbox and a rotatory axis, wherein the slats are mechanically connected to the rotatory axis, wherein the reduction gearbox is arranged between a drive shaft of a DC motor and the rotatory axis, such as to reduce a rotation angle of each step of the DC motor to a smaller rotation angle of the rotatory axis.
7. Shading device according to claim 6 , wherein the slats are mechanically connected to the rotatory axis via a multitude of strings, chains, or both strings and chains.
8. Shading device according to claim 1 , wherein the imaging system further comprises optical filters and an image sensor and an internal memory.
9. Shading device according to claim 1 , wherein the shading device comprises an electrochromic glazing, and the imaging system is configured to determine an optimal opacity of the electrochromic glazing.
10. Facade comprising the shading device according to claim 1 .
11. Method for illumination control, and for controlling a lighting system of a building, wherein the method uses the shading device according to claim 1 , wherein the method comprises:
an outside view calculation phase and
an illuminance calculation phase, and
a glare evaluation phase, and
a shading determination phase, and
a shading system adjustment step,
wherein the different phases are periodically repeated, by means of an infinite loop.
12. Shading device according to claim 1 , wherein the work-plane illuminance inside the target room is computed from the determined directional luminance distribution based on a ray-tracing algorithm or pre-computed matrices.
13. Shading device of claim 1 , wherein the glare risk is evaluated by computing a glare risk index from the determined directional luminance distribution based on a ray-tracing algorithm or pre-computed matrices.