Method for preventing incorrect lighting adjustment in a daylight harvesting system
First Claim
1. A method for preventing incorrect lighting adjustments in a daylight-harvesting system installed in a building, where the daylight harvesting system controls the output of a lighting system based on daylight and/or other light sources to reduce energy usage while providing a target light level for an area of the building, comprising:
- measuring a first light level using a first sensor that measures the current light level for the area;
measuring a second light level for a second area different from the area of the building using a second sensor;
detecting through the first sensor a change in the first light level;
determining from the second sensor whether the second light level has also changed; and
maintaining the target light level for the area;
wherein maintaining the target light level for the area involves adjusting the light output of the lighting system when the first sensor and the second sensor detect a correlated change in measured light levels; and
wherein adjusting the light output of the lighting system involves reducing the energy used by the lighting system when daylight and/or other light sources illuminate the area.
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Accused Products
Abstract
One embodiment of the present invention provides a system for preventing incorrect lighting changes in a daylight-harvesting system, which controls the output of a lighting system based on the presence of daylight and/or other light sources to reduce energy usage. During operation, the system measures a first light level using a first sensor. Next, the system measures a second light level for a different field-of-view using a second sensor. When the system detects through the first sensor a change in the first light level, the system determines from the second sensor whether the second light level has also changed. If the first sensor and the second sensor both detect a change (in the same direction) in the measured light levels, the system adjusts the light output of the lighting system to maintain target light levels for the area.
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Citations
20 Claims
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1. A method for preventing incorrect lighting adjustments in a daylight-harvesting system installed in a building, where the daylight harvesting system controls the output of a lighting system based on daylight and/or other light sources to reduce energy usage while providing a target light level for an area of the building, comprising:
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measuring a first light level using a first sensor that measures the current light level for the area; measuring a second light level for a second area different from the area of the building using a second sensor; detecting through the first sensor a change in the first light level; determining from the second sensor whether the second light level has also changed; and maintaining the target light level for the area; wherein maintaining the target light level for the area involves adjusting the light output of the lighting system when the first sensor and the second sensor detect a correlated change in measured light levels; and wherein adjusting the light output of the lighting system involves reducing the energy used by the lighting system when daylight and/or other light sources illuminate the area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus that prevents incorrect lighting adjustments in a daylight-harvesting system installed in a building, where the daylight harvesting system controls the output of a lighting system based on daylight and/or other light sources to reduce energy usage while providing a target light level for an area of the building, comprising:
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a measurement mechanism configured to measure a first light level using a first sensor that measures the current light level for the area; wherein the measurement mechanism is further configured to measure a second light level for a second area different from the area of the building using a second sensor; a detection mechanism configured to detect through the first sensor a change in the first light level; a determining mechanism configured to determine from the second sensor whether the second light level has also changed; and an adjustment mechanism configured to adjust the light output of the lighting system to maintain the target light levels for the area; wherein maintaining the target light level for the area involves adjusting the light output of the lighting system when the first sensor and the second sensor detect a correlated change in measured light levels; and wherein adjusting the light output of the lighting system involves reducing the energy used by the lighting system when daylight and/or other light sources illuminate the area. - View Dependent Claims (18, 19, 20)
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Specification