Horticulture Lighting Control Unit for PPFD Stability
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Solution Overview
Problem
Plants experience stress due to sudden changes in artificial lighting, which can lead to reduced photosynthesis and growth issues, especially in greenhouse environments where supplemental lighting is used, and LED lighting systems face thermal and mechanical stress from rapid current changes.
Innovation Solution
A horticulture lighting system with a control unit that gradually adjusts the photosynthetic photon flux density (PPFD) to prevent sudden changes in light intensity and spectral composition, ensuring that changes in PPFD do not exceed 50 μmol/sec/m2 over a predetermined period, and uses a combination of sensors and LED lighting to mimic natural daylight rhythms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If supplemental lighting is used in greenhouses to increase plant growth, then productivity is improved, but plants experience stress due to sudden changes in light intensity which reduces photosynthesis efficiency
Solution Approach 1:
The lighting system dynamically adjusts light intensity through gradual transitions rather than sudden changes. The control system modulates the intensity of supplemental lighting to match natural daylight rhythms, preventing plant stress while maintaining enhanced growth conditions.
Solution Approach 2:
The system implements periodic lighting patterns that mimic natural circadian rhythms. By varying light intensity in regular cycles that correspond to dawn and dusk patterns, the system maintains photosynthesis efficiency while still providing supplemental lighting benefits.
2Use of energy by moving object
If LED lighting systems are used to provide supplemental light, then energy efficiency is improved, but the LEDs experience thermal and mechanical stress from rapid current changes which reduces system lifespan
Solution Approach 1:
The control system implements gradual current transitions before and during LED operation changes. By cushioning the current changes rather than allowing rapid switches, the system protects LEDs from thermal and mechanical stress while maintaining energy-efficient operation.
Solution Approach 2:
The system maintains continuous, smooth current flow to LEDs without abrupt interruptions or changes. This continuous action prevents thermal cycling and mechanical stress that would otherwise reduce LED lifespan, while the lighting remains energy-efficient throughout operation.
3Stability of the object's composition
If light intensity is increased to compensate for sudden changes in natural daylight, then illumination stability is improved, but plant stress increases due to rapid PPFD changes
Solution Approach 1:
The control system anticipates changes in natural daylight and pre-adjusts supplemental lighting intensity. By detecting trends in natural light levels, the system makes gradual compensatory adjustments before significant illumination changes occur, maintaining stability without causing plant stress.
Solution Approach 2:
The system continuously monitors natural daylight levels and uses this feedback to modulate supplemental lighting intensity. The feedback loop ensures that adjustments are gradual and responsive, maintaining illumination stability while preventing harmful rapid changes that would stress plants.
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 plant stress, improves growth efficiency, and extends the lifespan of LED lighting systems by minimizing thermal and mechanical stress through gradual light adjustments and optimized light distribution.
Implementation Method 1
The light sources are configured to illuminate with horticulture light crops within said horticulture production facility
Implementation Method 2
Plants use the process of photosynthesis to convert light, CO2 and H2O into carbohydrates (sugars)
Implementation Method 3
the control unit is configured to prevent a change in the photosynthetic photon flux density (PPFD) of the local light at the location within the horticulture production facility of on average more than 50 μmol/sec/m2 over a predetermined period of time
Data Source
AI summary
The invention provides a lighting system comprising (i) a lighting device comprising a plurality of light sources for application in a horticulture production facility, wherein the light sources are configured to illuminate with horticulture light crops, wherein the lighting system further comprises (ii) a control unit configured to control the light intensity of local light at a location, wherein the local light is the sum of the horticulture light and light at the location originating from an optional other light source, and wherein the control unit is configured to prevent a change in the photosynthetic photon flux density (PPFD) of the local light at the location of on average more than 50 nmol/sec/m2 over a predetermined period of time selected from the range of equal to or smaller than 5 minutes by controlling the contribution of the horticulture light to the local light.