Greenhouse Lighting Control Using Broadband Sunlight Sensing
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Solution Overview
Problem
Existing greenhouse lighting systems consume significant energy and have a non-negligible carbon footprint, and existing control methods for artificial lighting in horticulture are inefficient in maintaining optimal photosynthetic active radiation (PAR) levels without requiring complex spectral measurements.
Innovation Solution
A method and system that control artificial lighting by adjusting individual light components based on a non-spectrally resolved irradiance value of sunlight, allowing plants to receive appropriate PAR levels efficiently without complex spectral measurements, using simple irradiance sensors and control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If artificial lighting is used to maintain optimal PAR levels for plant growth, then plant growth and productivity are improved, but energy consumption increases
Solution Approach 1:
The system continuously measures the actual PAR level received by plants using sensors and adjusts artificial lighting intensity accordingly. The control unit receives sensor signals indicating current PAR levels and modifies lighting output to maintain optimal growth conditions while minimizing energy waste, creating a closed-loop feedback system that adapts to changing environmental conditions.
Solution Approach 2:
The lighting system transitions from static, fixed-intensity illumination to dynamic, adaptive lighting that automatically adjusts its output based on real-time environmental conditions. The system modulates lighting intensity and spectral composition in response to varying natural light availability, plant growth stage, and measured PAR levels, optimizing energy efficiency while maintaining productivity.
2Measurement precision
If spectrally resolved sensors are used to measure sunlight components, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system introduces a spectral transformation layer that converts measurements from simple broadband irradiance sensors into spectrally resolved information. By using pre-calibrated spectral signatures of sunlight and artificial light sources, the control unit can estimate individual wavelength component levels without requiring complex spectrometers, effectively using simple sensors as intermediaries to achieve spectral measurement goals.
Solution Approach 2:
The system creates virtual spectral measurements by copying and applying known spectral characteristics of light sources to total irradiance measurements. Instead of directly measuring each wavelength component with complex hardware, the system replicates expected spectral distributions based on sensor readings and environmental conditions, deriving useful spectral information through computational copying rather than physical measurement.
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
Maintains high light use efficiency by adapting artificial light components to sunlight changes, ensuring optimal PAR levels while reducing energy consumption and minimizing waste, using simple sensors and control systems.
Implementation Method 1
receiving a signal from a sensor indicative of a non-spectrally resolved irradiance value of sunlight that is incident on the one or more plants
Implementation Method 2
Plants use light as the energy source for assimilating CO2 from the ambient air and converting it into biomass. This process is called photosynthesis.
Data Source
AI summary
A computer-implemented method is disclosed for controlling one or more luminaires that are configured to illuminate one or more plants with artificial light. The artificial light comprises a plurality of artificial light components. Each of the artificial light components is of a respective wavelength or wavelength range. The plurality of artificial light components comprises a first artificial light component of a first wavelength or wavelength range and a second artificial light component of a second wavelength or wavelength range. Further, sunlight is incident on the one or more plants. The sunlight comprises a plurality of sunlight components. Each of the sunlight components is of a respective wavelength or wavelength range. The plurality of sunlight components comprising a first sunlight component of the first wavelength or wavelength range and a second sunlight component of the second wavelength or wavelength range. The method comprises receiving a signal indicative of a non-spectrally resolved irradiance value of sunlight that is incident on the one or more plants.