Solar-Correlated Lighting Control Subsystem for Energy Efficiency
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Solution Overview
Problem
Conventional lighting systems face inefficiencies due to the long warm-up time of high-intensity discharge light sources and the limitations of dusk-to-dawn control mechanisms, which fail to adjust lighting levels according to changing daylight conditions, leading to unnecessary energy consumption and inadequate illumination.
Innovation Solution
A control subsystem that adjusts lighting levels based on solar time, correlating sensor data with a clock to turn lights on, off, or dim them according to the natural diurnal cycle, using multiple samples to filter out aberrant conditions and accommodate seasonal changes in daylight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If dusk-to-dawn control mechanisms with fixed thresholds are used, then automatic accommodation of daylight changes is achieved, but premature or delayed lighting activation occurs due to incorrect threshold settings
Solution Approach 1:
The control mechanism dynamically adjusts the turn-on and turn-off thresholds based on the measured duration of natural darkness. Instead of using fixed thresholds, the system adapts the thresholds to match the actual diurnal cycle characteristics, ensuring reliable operation across varying seasonal conditions and artificial light environments.
Solution Approach 2:
The system measures the actual darkness duration over multiple cycles and uses this feedback to recalibrate the control thresholds. By continuously monitoring when the environment transitions between light and dark states, the system learns the correct thresholds for its specific location and adjusts accordingly, eliminating premature or delayed activation.
2Use of energy by moving object
If higher efficiency light sources such as fluorescent or HID lamps are used, then energy consumption is reduced, but long warm-up time and high initial energy consumption occur
Solution Approach 1:
The control system activates the high-efficiency light sources slightly before the actual darkness begins, based on predicted timing from the learned diurnal cycle. This preliminary activation allows the lamps to complete their warm-up period before full illumination is needed, ensuring both energy efficiency and adequate lighting when darkness falls.
Solution Approach 2:
The system uses periodic measurement of darkness duration over multiple cycles to establish a predictable pattern. By understanding the regular periodic nature of the diurnal cycle, the controller can anticipate when lighting is needed and activate the efficient but slow-response light sources at the optimal time.
3Adaptability or versatility
If fixed turn-on and turn-off thresholds are set to accommodate wide range of conditions, then broad applicability is achieved, but incorrect thresholds result for specific applications
Solution Approach 1:
The control system performs self-calibration by automatically measuring the actual darkness duration and determining the appropriate thresholds for its specific installation location. Instead of relying on manufacturer-set generic thresholds, the system serves itself by learning the local diurnal characteristics and configuring optimal thresholds without user intervention.
Solution Approach 2:
The system changes the threshold parameters dynamically based on measured environmental conditions. By monitoring the actual light levels and darkness duration over multiple cycles, the system adjusts the turn-on and turn-off threshold values to match the specific application, whether in high artificial light environments or areas with minimal artificial lighting.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces energy consumption by providing adequate illumination only when needed, while ensuring that lighting systems function effectively across varying daylight conditions, reducing the need for manual adjustments and minimizing the impact of artificial light sources.
Implementation Method 1
determined by the control subsystem based on levels of light or illumination sensed by the sensor
Data Source
AI summary
An illumination system correlates solar time to a clock and controls lighting or illumination based on time. The illumination system may turn ON light source(s) at a first level at a turn ON time, correlated to be around or at dusk, and turn OFF light source(s) at a turn OFF time, correlated to be around or at dawn. The illumination system may reduce a level of light output, and hence power consumption, at a time after turning ON a light source, and increases the level of light output at a time prior to turning OFF the light source. Turn ON, turn OFF, decrease and increase times may be determined based on recent levels of light or illumination in the environment, for example via average or median levels over a number of previous daily cycles. Filtering may eliminate aberrant events.