Rotating Light Rods in Algae Bioreactors
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Solution Overview
Problem
Current algae production systems face limitations in photosynthetic efficiency due to restricted light wavelength, excessive light intensity, and bio-filming issues, which hinder high-density growth and biomass production, leading to suboptimal yields and increased production costs.
Innovation Solution
A photo-bioreactor design featuring rotating light-emitting rods within a reactor vessel, which provides controlled light distribution and circulation of the fluid medium to optimize light exposure and reduce bio-filming, combined with a drive system for rotating the rods to create alternating light and dark conditions, enhancing photosynthetic efficiency and growth rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional algae production systems use stationary light sources, then the system structure is simple, but photosynthetic efficiency is limited due to restricted light wavelength and excessive light intensity
Solution Approach 1:
The patent applies the dynamics principle by transforming stationary light sources into rotating light-emitting rods. The rods rotate at controlled speeds to dynamically distribute light throughout the culture medium, ensuring all algae cells receive appropriate light exposure. This dynamic approach resolves the contradiction by improving photosynthetic efficiency through enhanced light distribution while maintaining manageable system complexity through the use of simple rotational mechanics.
Solution Approach 2:
The rotating light-emitting rods create periodic light exposure patterns for the algae culture. As the rods rotate, they create alternating zones of light and darkness that simulate natural circadian rhythms, enhancing photosynthetic efficiency. This periodic action allows the system to achieve higher productivity by mimicking natural light cycles while keeping the device structure relatively simple.
2Productivity
If high light intensity is used to accelerate algae growth, then growth rate increases, but photo-inhibition and cell damage occur
Solution Approach 1:
The rotating light-emitting rods create localized light zones that move through the culture medium. At any given moment, only specific regions receive high-intensity light, while other regions are in darkness or receive diffused light. This local quality approach ensures that no single area is continuously exposed to excessive light intensity, preventing photo-inhibition and cell damage while maintaining high overall growth rates.
Solution Approach 2:
The rotation of light-emitting rods creates periodic exposure patterns where algae cells experience alternating high-intensity light and darkness. This periodic action prevents continuous exposure to damaging light levels, allowing cells to recover during dark periods while still achieving high growth rates during light exposure phases.
3Device complexity
If stationary light sources are used in bioreactors, then device complexity is low, but bio-filming occurs on light source surfaces
Solution Approach 1:
By rotating the light-emitting rods, the system prevents algae and microorganisms from settling and forming bio-films on the light source surfaces. The continuous motion disrupts the adhesion process, keeping the light-emitting surfaces clean and maintaining optical efficiency without requiring complex anti-fouling mechanisms.
4Area of stationary object
If high-density algae culture is pursued, then space efficiency improves, but light distribution becomes insufficient
Solution Approach 1:
The rotating light-emitting rods dynamically distribute light throughout the high-density culture medium. As the rods rotate, they sweep light across different zones, ensuring even distribution to densely packed algae cells. This dynamic light distribution enables high-density culture while maintaining sufficient illumination for photosynthesis.
Solution Approach 2:
The rotating rods introduce temporal and spatial dimensionality to light distribution. Instead of static light sources illuminating only nearby cells, the rotating rods create a three-dimensional light distribution pattern that reaches cells throughout the culture volume, enabling effective high-density cultivation.
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 achieves higher algae growth rates and densities, reducing production costs and space requirements while minimizing damage to algae cells, thereby improving the overall efficiency and scalability of algae production.
Implementation Method 1
a first light-emitting rod and a second light-emitting rod, spaced apart a proximal distance from said first-light emitting rod, said light-emitting rods each extending into said reactor vessel, said light-emitting rod comprising an elongate tubular member characterized by a length along a longitudinal axis and a width along an axis normal to said longitudinal axis, and designed with an outer wall that encloses one or more light-emitting devices arranged along said longitudinal axis
Implementation Method 2
A photo-bioreactor for production of bio-materials... A photo-bioreactor design featuring rotating light-emitting rods within a reactor vessel, which provides controlled light distribution and circulation of the fluid medium to optimize light exposure and reduce bio-filming, combined with a drive system for rotating the rods to create alternating light and dark conditions, enhancing photosynthetic efficiency and growth rates
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A photo-bioreactor and method of operating are described. The photo-bioreactor includes a reactor vessel arranged to contain a fluid medium within which bio-material is grown, and at least one light-emitting rod extending into the reactor vessel, wherein the light-emitting rod has an elongate tubular member characterized by a length along a longitudinal axis and a width along an axis normal to the longitudinal axis, and designed with an outer wall that encloses one or more light-emitting devices arranged along the longitudinal axis, the outer wall being transparent to at least part of the light emitted by the one or more light-emitting devices into the reactor vessel. The photo-bioreactor further includes a drive system coupled to the elongate tubular member, and operatively configured to rotate the light-emitting rod about the longitudinal axis within reactor vessel, and circulate the fluid medium through the reactor.