SYSTEM TO CONTROL SUN GLARE IN A SPACE

• US 20070211447A1
• Filed: 09/08/2006
• Published: 09/13/2007
• Est. Priority Date: 03/24/2003
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Veskovic, Dragan
• Granted Patent: US 7,588,067 B2
• Time in Patent Office: Days
• US Class Current: 362/1
• CPC Class Codes: E06B 9/32 Operating, guiding, or securing devices therefor operation of tilting bars E06B9/307
• CPC Class Codes: E06B 9/68 Operating devices or mechanisms, e.g. with electric drive
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]
• CPC Class Codes: Y02A 30/24 Structural elements or technologies for improving thermal insulation
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y02B 80/00 Architectural or constructional elements improving the thermal performance of buildings
• CPC Class Codes: Y10S 362/802 Position or condition responsive switch

Abstract

A system for reducing sun glare through an opening into a space, the system comprising an electrically controllable window treatment operable to alter the amount of daylight entering the space through the opening; a first sensor mounted within the space and characterized by a sensor gain, the first sensor operable to sense a level of illumination in the space; and a control system operable: to compare the sensed illumination level in the space to a dead-band having upper and lower thresholds; to adjust during a time period when glare from the sun can occur through the opening at least one of: (a) the upper threshold of the dead-band, (b) the lower threshold of the dead-band, and (c) the sensor gain of the first sensor; and to adjust the window treatment in response to the sensed level of illumination to reduce the sun glare.

Claims

1. A system for reducing sun glare through an opening into a space, the system comprising:

an electrically controllable window treatment operable to alter the amount of daylight entering the space through the opening;

a first sensor mounted within the space and characterized by a sensor gain, the first sensor operable to sense a level of illumination in the space; and

a control system operable;

to compare the sensed illumination level in the space to a dead-band having upper and lower thresholds;

to adjust during a time period when glare from the sun can occur through the opening at least one of;

(a) the upper threshold of the dead-band, (b) the lower threshold of the dead-band, and (c) the sensor gain of the first sensor; and

to adjust the window treatment in response to the sensed level of illumination to reduce the sun glare.

2. The system of claim 1, wherein the control system includes an astronomical time clock and is operable to adjust in response to a present time of the day at least one of:

(a) the upper threshold of the dead-band, (b) the lower threshold of the dead-band, and (c) the sensor gain of the first sensor.

3. The system of claim 2, wherein the astronomical time clock is operable to determine the present time of the day.

4. The system of claim 3, wherein the control system is further operable to adjust during a first time period after sunrise and during a second time period before sunset at least one of:

(a) the upper threshold of the dead-band, (b) the lower threshold of the dead-band, and (c) the sensor gain of the first sensor.

5. The system of claim 4, wherein the first time period ranges from sunrise to three hours after sunrise and the second time period ranges from three hours before sunset to sunset.

6. The system of claim 2, wherein the control system is further operable to determine from a look-up table using the present time of the day at least one of:

(a) the upper threshold of the dead-band, (b) the lower threshold of the dead-band, and (c) the sensor gain of the first sensor.

7. The system of claim 2, wherein the control system is further operable to correct for a spectral sensitivity property of the first sensor using the present time of the day.

8. The system of claim 1, further comprising:

adjustment means operable to allow a user to manually adjust the window treatment.

9. The system of claim 8, wherein the control system is further operable to temporarily adjust at least one of the upper and lower thresholds of the dead-band in response to an illumination level sensed after a manual adjustment of the window treatment.

10. The system of claim 9, wherein the control system is operable to restore the upper and lower thresholds to default values after the sensed illumination level exceeds one of the upper and lower thresholds of the temporary dead-band.

11. The system of claim 10, wherein the control system is further operable to automatically adjust the upper and lower thresholds after the control system detects a repeated manual adjustment of the window treatment.

12. The system of claim 9, wherein the control system is operable to restore the upper and lower thresholds of a default dead-band after a predetermined amount of time after a manual adjustment of the window treatment.

13. The system of claim 1, further comprising:

a plurality of electric lamps providing artificial light to supplement the daylight illumination of the space, the electric lamps being dimmable and being arranged in one or more zones in the space, the zones defining predefined volumes of the space, each zone having at least one lamp;

wherein the control system is further operable to control the dimming levels of the plurality of electric lamps and to control the window treatment to control the amount of daylight entering the space through the opening, such that the control system is operable to maintain a desired illumination profile in the space, the at least one lamp of each zone being controlled to a dimming level to achieve a desired illumination level in the respective zone according to the desired illumination profile.

14. The system of claim 13, wherein the control system is further operable to select the dimming level of each lamp from one of a plurality of lighting presets, each lighting preset comprising a combination of dimming levels of the lamps;

and

the control system is further operable to adjust the dimming level of the electric lamps toward a preset that will result in an appropriate supplementing of the daylight illumination to achieve the desired illumination profile in the space, such that, when the desired illumination profile is achieved within a predefined tolerance, the control system is further operable to stop adjusting the dimming levels of the lamps towards the preset.

15. The system of claim 14, wherein the control system is further operable to control both the window treatment and the plurality of electric lamps in response to the sensed illumination level from the first sensor.

16. The system of claim 14, further comprising:

a second sensor mounted in the space for sensing the illumination level in the space;

wherein the control system is further operable to adjust the dimming level of the plurality of electric lamps and to adjust the window treatment to maintain a desired illumination profile in response to the sensed illumination level from the second sensor.

17. The system of claim 1, wherein the control system is further operable to adjust the window treatment to bring the sensed illumination level in the space within the upper and lower thresholds of the dead-band.

18. The system of claim 17, wherein the control system is further operable to delay for a predetermined amount of time before adjusting the window treatment in response to the sensed illumination level.

19. The system of claim 18, wherein the control system is further operable to reduce the predetermined amount of time if the sensed illumination is consistently higher than the upper threshold or consistently lower than the lower threshold.

20. The system of claim 1, wherein the control system is further operable to decrease the upper and lower thresholds of the dead-band during the time period when glare from the sun can occur through the opening.

21. The system of claim 1, wherein the control system is further operable to increase the sensor gain of the first sensor during the time period when glare from the sun can occur through the opening.

22. The system of claim 1, wherein the control system is further operable to stop the adjustment of the window treatment in response to the sensed level of illumination.

23. A method for reducing sun glare through an opening into a space, the method comprising the steps of:

providing an electrically controllable window treatment in relation to the opening for selectively altering the amount of daylight entering the space through the opening;

sensing a level of illumination in the space;

comparing the sensed illumination level in the space to a dead-band having upper and lower thresholds;

adjusting at least one of the upper and lower thresholds of the dead-band during a time period when glare from the sun can occur through the opening; and

adjusting the window treatment to reduce the sun glare in response to the step of comparing.

24. The method of claim 23, wherein the step of adjusting at least one of the upper and lower thresholds further comprises adjusting at least one of the upper and lower thresholds of the dead-band in response to a present time of the day.

25. The method of claim 24, further comprising the step of:

determining the present time of the day from an astronomical time clock.

26. The method of claim 25, wherein the step of adjusting at least one of the upper and lower thresholds further comprises adjusting at least one of the upper and lower thresholds of the dead-band during a first time period after sunrise and during a second time period before sunset.

27. The method of claim 26, wherein the first time period ranges from sunrise to three hours after sunrise and the second time period ranges from three hours before sunset to sunset.

28. The method of claim 24, wherein the step of adjusting at least one of the upper and lower thresholds further comprises determining the upper and lower thresholds of the dead-band from a look-up table using the present time of the day.

29. The method of claim 24, further comprising the step of:

correcting for a spectral sensitivity property of the first sensor using the present time of the day.

30. The method of claim 23, further comprising the steps of:

manually adjusting the window treatment; and

subsequently temporarily adjusting at least one of the upper and lower thresholds of the dead-band around the sensed illumination level measured after the step of manually adjusting.

31. The method of claim 30, further comprising the step of:

restoring the upper and lower thresholds to default values after the sensed illumination level exceeds the temporarily adjusted upper and lower thresholds.

32. The method of claim 31, further comprising the steps of:

detecting a repeating manual adjustment of the window treatment; and

automatically adjusting the upper and lower thresholds in response to detecting the repeating manual adjustment of the window treatment.

33. The method of claim 32, further comprising the step of:

restoring the upper and lower thresholds to default values after a predetermined amount of time after the step of manually adjusting.

34. The method of claim 23, further comprising the steps of:

controlling the window treatment to control the amount of daylight entering the space through the opening;

supplementing the daylight illumination of the space with artificial light from a plurality of dimmable electric lamps arranged in one or more zones in the space, the zones defining predefined volumes of the space, each zone having at least one lamp; and

controlling the dimming levels of the plurality of electric lamps, such that the at least one lamp of each zone is controlled to a dimming level so as to achieve a desired illumination level in the respective zone according to a desired space illumination profile.

35. The method of claim 34, wherein the step of controlling the dimming levels comprises selecting the dimming level of each lamp from one of a plurality of lighting presets, each lighting preset comprising a combination of dimming levels of the lamps, and adjusting the dimming level of the electric lamps toward the one preset that will result in an appropriate supplementing of the daylight illumination to achieve the desired illumination profile in the space, such that, when the desired illumination profile is achieved within a predefined tolerance, the control system stops adjusting the dimming levels of the lamps.

36. The method of claim 35, further comprising the step of:

sensing a second illumination level in the space;

wherein the step of controlling the dimming levels comprises adjusting the dimming level of the plurality of electric lamps in response to the sensed second illumination level.

37. The method of claim 24, wherein the step of adjusting the window treatment comprises delaying for a predetermined amount of time and then adjusting the window treatment to bring the sensed illumination level in the space within the dead-band.

38. The method of claim 37, wherein the predetermined amount of time is reduced if the sensed illumination is consistently higher than the upper threshold or consistently lower than the lower threshold.

39. The method of claim 24, wherein the step of adjusting at least one of the upper and lower thresholds further comprises reducing the upper and lower thresholds of the dead-band during the time period when glare from the sun can occur through the opening.

40. The method of claim 24, further comprising the step of:

stopping adjustment of the window treatment in response to the step of comparing.

41. The method of claim 24, further comprising the step of:

applying a sensor gain to the sensed illumination level to generate a corrected sensed illumination level;

wherein the step of comparing comprises comparing the corrected sensed illumination level in the space to the dead-band.

42. A method for reducing sun glare through an opening into a space, the method comprising the steps of:

providing an electrically controllable window treatment in relation to the opening for selectively altering the amount of daylight entering the space through the opening;

sensing a level of illumination in the space;

applying a sensor gain to the sensed illumination level to generate a corrected sensed illumination level;

comparing the corrected sensed illumination level in the space to a dead-band having upper and lower thresholds;

adjusting the sensor gain during a time period when glare from the sun can occur through the opening; and

adjusting the window treatment to reduce the sun glare in response to the step of comparing.

43. The method of claim 42, wherein the step of adjusting the sensor gain further comprises adjusting the sensor gain in response to a present time of the day.

44. The method of claim 43, further comprising the step of:

determining the present time of the day from an astronomical time clock.

45. The method of claim 44, wherein the step of adjusting the sensor gain further comprises adjusting the sensor gain during a first time period after sunrise and during a second time period before sunset.

46. The method of claim 45, wherein the first time period ranges from sunrise to three hours after sunrise and the second time period ranges from three hours before sunset to sunset.

47. The method of claim 43, wherein the step of adjusting the sensor gain further comprises determining the sensor gain from a look-up table using the present time of the day.

48. The method of claim 43, further comprising the step of:

correcting for a spectral sensitivity property of the first sensor using the present time of the day.

49. The method of claim 42, further comprising the steps of:

controlling the window treatment to control the amount of daylight entering the space through the opening;

supplementing the daylight illumination of the space with artificial light from a plurality of dimmable electric lamps arranged in one or more zones in the space, the zones defining predefined volumes of the space, each zone having at least one lamp; and

controlling the dimming levels of the plurality of electric lamps, such that the at least one lamp of each zone is controlled to a dimming level so as to achieve a desired illumination level in the respective zone according to a desired space illumination profile.

50. The method of claim 49, wherein the step of controlling the dimming levels comprises selecting the dimming level of each lamp from one of a plurality of lighting presets, each lighting preset comprising a combination of dimming levels of the lamps, and adjusting the dimming level of the electric lamps toward the one preset that will result in an appropriate supplementing of the daylight illumination to achieve the desired illumination profile in the space, such that, when the desired illumination profile is achieved within a predefined tolerance, the control system stops adjusting the dimming levels of the lamps.

51. The method of claim 50, further comprising the step of:

sensing a second illumination level in the space;

wherein the step of controlling the dimming levels comprises adjusting the dimming level of the plurality of electric lamps in response to the sensed second illumination level.

52. The method of claim 42, wherein the step of adjusting the window treatment comprises delaying for a predetermined amount of time and then adjusting the window treatment to bring the sensed illumination level in the space within the dead-band.

53. The method of claim 52, wherein the predetermined amount of time is reduced if the sensed illumination is consistently higher than the upper threshold or consistently lower than the lower threshold.

54. The method of claim 42, wherein the step of adjusting the window treatment further comprises increasing the sensor gain during the time period when glare from the sun can occur through the opening.

55. The method of claim 42, further comprising the step of:

stopping adjustment of the window treatment in response to the step of comparing.