Hybrid Plant Lighting Control for Lower-Energy Indoor Farming

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Solution Overview

Problem

The high energy consumption and operating costs of conventional indoor farming systems, particularly due to reliance on artificial lighting, hinder the widespread adoption of vertical farming technologies, which are crucial for sustainable urban food production in densely populated cities with limited agricultural land and resources.

Innovation Solution

A lighting device combining adjustable artificial and sunlight units, with a mixing, distribution, and control system that dynamically adjusts light properties to optimize plant growth conditions, using LEDs for artificial light and a solar collector, and includes optical filtering and sensor-based control to minimize energy use and extend light source lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If artificial lighting is used exclusively for plant illumination in indoor farming, then plant growth can be controlled and optimized, but energy consumption and operating costs increase significantly

Engineering Contradiction:
Improveplant growth controlVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent combines artificial light sources with natural sunlight to create a hybrid illumination system. The artificial light units provide controlled spectral components while sunlight units contribute natural full-spectrum light, reducing the energy burden on artificial sources while maintaining growth optimization benefits

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lighting device integrates multiple light sources (artificial and natural) into a single system that can adapt to different growth stages and conditions. The system universally serves both controlled supplementation and natural light utilization functions

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If artificial light intensity is increased to maximize plant growth, then productivity improves, but light source lifespan decreases and energy consumption increases

Engineering Contradiction:
Improveplant growth rateVSAvoidlight source lifespan
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

By merging artificial and natural light sources, the system achieves high total light intensity for maximum plant growth without requiring artificial sources to operate at maximum intensity continuously, thereby extending their operational lifespan

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses artificial light only to supplement natural sunlight to the extent necessary for optimal growth, rather than relying exclusively on artificial light at full intensity, reducing stress on artificial light sources

Inventive Principle:
Principle #16Partial or excessive action

3Use of energy by moving object

If natural sunlight is used for plant illumination, then energy consumption is reduced, but control over spectral distribution and intensity is limited

Engineering Contradiction:
Improveenergy consumptionVSAvoidspectral control
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The system applies different spectral characteristics to different spatial zones or plant types by selectively combining artificial light units with specific spectral outputs and sunlight units, allowing localized optimization for different plant requirements

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lighting device dynamically adjusts the ratio and intensity of artificial versus natural light based on plant growth stage, time of day, and environmental conditions, providing adaptive spectral control that responds to changing plant needs

Inventive Principle:
Principle #15Dynamics

4Productivity

If vertical farming is implemented in densely populated cities, then food production proximity to consumers improves, but available agricultural land and resources are limited

Engineering Contradiction:
Improveurban food productionVSAvoidagricultural land area
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The lighting device enables vertical farming by providing optimized illumination for multi-layer plant cultivation in vertical spaces, transforming two-dimensional land use into three-dimensional space utilization, thereby increasing food production per unit of ground area

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The system reduces energy costs and extends light source life, enabling efficient, adaptable, and resource-conserving indoor farming by optimizing light mixtures for plant growth, enhancing growth uniformity and efficiency across all growth phases.

Implementation Method 1

which, for example, uses light-emitting diodes (LEDs) as artificial light sources

Methodology Applied
Scientific EffectLight-emitting diode (LED): Light Emitting Diode

Implementation Method 2

a mixing unit for generating a mixed light from artificial light and sunlight

Methodology Applied
Scientific EffectLight mixing:

Implementation Method 3

The sunlight that is mixed with artificial light in the mixing unit can therefore also be filtered and thus modified sunlight

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentEP3993605B1Lighting device and lighting method for at least one plant
Publication Date: 2025.12.17 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3993605B1 patent drawingFigure 1

AI summary

The invention relates to a lighting device (1) for at least one plant (2), comprising an artificial lighting unit (3) for providing artificial light (3') for lighting the plant (2); a sunlight unit (4) for providing sunlight (4') for lighting the plant (2); a mixing unit (5) for generating a mixed light (5') consisting of the artificial light (3') and the sunlight (4'); a distributing unit (6) for distributing the mixed light (5') and lighting the plant (2) with the distributed mixed light (5'); and an adjustment unit (8) for adjusting a property of the mixed light (5'). The invention provides a lighting device for at least one plant, i.e. one or more plants, wherein the device can be used in an energy-saving manner for indoor farming.