Photobioreactor Lighting Mixing System for Algae Growth
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Solution Overview
Problem
Current photobioreactors are inefficient in delivering light to all areas of the liquid medium, leading to reduced microbial growth due to light saturation and photoinhibition, which limits the production of biomass such as biodiesel and ethanol.
Innovation Solution
A photobioreactor with a rotating and/or oscillating lighting and mixing system that includes a light source outside the tank, mounted on mixing blades or frames, and a conduit to transfer light throughout the tank, ensuring uniform light distribution and nutrient availability for optimal microbial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light is provided from above the liquid medium, then the lighting system is simple to implement, but light penetration is limited to a few centimeters from the surface
Solution Approach 1:
The patent introduces an intermediary substance (light-transmitting material) that facilitates light penetration into the liquid medium. This material acts as a mediator between the light source and the microbial culture, enabling deeper and more uniform light distribution throughout the photobioreactor without requiring complex multi-directional lighting systems.
Solution Approach 2:
The patent transitions from vertical light delivery (top-down) to horizontal light delivery through the walls of the photobioreactor. This dimensional change allows light to penetrate the liquid medium from the sides, achieving uniform illumination throughout the volume without increasing lighting system complexity.
2Productivity
If algae are cultivated in large volume tanks, then production capacity increases, but light distribution becomes insufficient in large portions of the culture
Solution Approach 1:
The patent applies local quality by providing light delivery through the walls of the photobioreactor, ensuring that each local region of the liquid medium receives adequate illumination. This approach allows large volume tanks to maintain uniform light distribution throughout, enabling high productivity without sacrificing light penetration quality.
3Ease of operation
If stationary lighting systems are used, then the system is simple to operate, but light reaches only the top layer of algae
Solution Approach 1:
The patent introduces dynamic elements to the lighting system, such as rotating or oscillating light-emitting components, that move throughout the photobioreactor volume. This dynamic approach ensures comprehensive light distribution to all layers of algae culture while maintaining operational simplicity through automated motion control.
Solution Approach 2:
The patent implements continuous light delivery throughout the photobioreactor volume by using rotating or oscillating mechanisms that continuously expose different regions to light. This ensures uninterrupted photosynthetic activity throughout the entire culture volume, maximizing overall algae growth efficiency.
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 solution significantly increases the efficiency of photobioreactor systems by allowing light and nutrients to reach all areas, reducing the required space for algae growth by 10 to 100 times and enhancing biomass production.
Implementation Method 1
a conduit that transfers light from the light source to the light emitting device
Implementation Method 2
a rotating mixing system comprising one or more motors, and one or more shafts connected to the one or more motors, and a plurality of mixing blades attached to the one or more shafts
Implementation Method 3
Algae have been cultivated artificially for such diverse purposes as the production of food for animals and humans... and for producing oils and other materials having value as fuels such as biodiesel fuel or ethanol
Data Source
AI summary
The present invention is directed to a photobioreactor comprising: (a) a tank for containing a liquid microbial culture; (b) a rotating mixing system contained within the tank, the rotating mixing system comprising one or more motors, and one or more shafts connected to the one or more motors, and a plurality of mixing blades attached to the one or more shafts, wherein the mixing blades are capable of mixing the microbial culture throughout the volume of the tank; (c) a lighting system, comprising a light source located outside the tank; a light emitting device mounted on the blades; and a conduit that transfers light from the light source to the light emitting device, wherein the lighting system is capable of providing sufficient light for growth of the microbial culture throughout the volume of the tank. The rotating system may be replaced with an oscillating system, and either system can be mounted on a moveable raceway.