Segmented Light Diffuser for Uniform Algae Cultivation

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Solution Overview

Problem

Conventional algae cultivation methods face challenges in providing sufficient and uniform light penetration due to the exponential attenuation of light as it enters the culture medium, leading to inefficient biomass production and metabolite yields, particularly in closed photobioreactors.

Innovation Solution

A fluid-tight light diffuser with irregularities on its surface is designed to diffuse light uniformly throughout the cultivation medium, allowing for precise control of light intensity and reducing algae growth on the surface, which can be easily cleaned and replaced, thus improving energy efficiency and reducing downtime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light is provided from above the culture surface or laterally, then the light source can be positioned outside the cultivation medium, but light penetration depth is insufficient and only a narrow zone close to the surface receives sufficient light

Engineering Contradiction:
Improvelight penetration depthVSAvoidcultivation tank structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light source is divided into multiple segments along the cultivation medium, with individual light sources positioned at different locations including bottom, side, and top surfaces. This segmentation allows light to be distributed throughout the volume, overcoming the limitation of single-point illumination and enabling sufficient light penetration to deeper zones without requiring complex tank restructuring

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from traditional two-dimensional surface illumination (top or side only) to three-dimensional volumetric illumination by positioning light sources in multiple spatial dimensions including the bottom surface, vertical sides, and top surface of the cultivation medium. This multi-dimensional approach enables light to reach all zones of the culture volume effectively

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

2Illumination intensity

If very shallow structure of the cultivation tank is used to overcome light attenuation, then light can reach the culture, but space efficiency and energy efficiency are reduced

Engineering Contradiction:
Improvelight availabilityVSAvoidcultivation volume
Core Design Contradiction:
Illumination intensityVSVolume of stationary object

Solution Approach 1:

The illumination system is segmented into multiple light sources positioned at different locations (bottom, sides, top) rather than relying on a single surface light source. This enables deep cultivation volumes to receive adequate light without reducing tank depth, thereby maintaining high cultivation volume while ensuring sufficient light availability throughout the medium

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the cultivation medium receive light from different directions and sources - bottom zones receive light from below, side zones from lateral sources, and surface zones from above. This localized illumination approach allows the entire volume to receive appropriate light intensity without requiring the entire tank to be shallow

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If strong movement of the cultivation medium is applied to distribute light, then light penetration is improved, but energy efficiency and CO2 availability are compromised

Engineering Contradiction:
Improvelight distributionVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

Instead of using strong bulk movement to distribute light, the system segments the illumination into multiple stationary light sources positioned throughout the cultivation volume. This eliminates the need for high-energy mixing while ensuring uniform light distribution, as each zone receives light from its nearest source without requiring medium movement

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention replaces the mechanical mixing approach (strong medium movement) with a stationary multi-point illumination system. Light distribution is achieved through the spatial arrangement of multiple light sources rather than mechanical agitation, significantly reducing energy consumption while maintaining effective light distribution throughout the cultivation medium

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 light diffuser ensures even illumination, preventing photoinhibition and enhancing photosynthesis, leading to improved biomass production and energy efficiency in algae cultivation by minimizing light attenuation and facilitating optimal light distribution within the cultivation tank.

Implementation Method 1

The diffuser body (10) of a first material contains irregularities in said first material providing diffusing structures (11; 11'; 11"; 11'''') for diffusing the light of the light source (3), such that the light exits the diffuser body (10) at a predefined intensity in different parts over the length of the diffuser body (10)

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

One major problem in designing efficient bioreactors for phototrophic microalgae arises from the fact that light attenuates exponentially as it penetrates into the culture medium

Methodology Applied
Scientific EffectLight attenuation: Absorption (EM radiation)

Data Source

PatentEP4464768A1Light diffuser
Publication Date: 2024.11.20 AGRI-BIOTECH OY
  • EP4464768A1 patent drawingFigure 1~2
  • EP4464768A1 patent drawingFigure 3~4
  • EP4464768A1 patent drawingFigure 5

AI summary

The invention relates to a fluid tight light diffuser (1), the light diffuser (1) comprising an elongated diffuser body (10) comprising a first end (10a), and a second end (10b), the first end (10a) receiving a light from a light source (3). Further, the diffuser body (10) of a first material contains irregularities in said first material providing diffusing structures (11; 11'; 11"; 11‴) for diffusing the light of the light source (3), such that the light exits the diffuser body (10) at a predefined intensity in different parts over the length of the diffuser body (10).