Container Air Composition Control for Low-CO2 Plant Storage

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Solution Overview

Problem

In carbon dioxide priority control systems for plant storage, the gas supply operation does not start until the carbon dioxide concentration reaches a predetermined starting concentration higher than the target, leading to slow increase in carbon dioxide concentration and ineffective air composition control, potentially causing plants to lose freshness if the initial carbon dioxide amount is small.

Innovation Solution

An inside air control apparatus with a gas supply device that can adjust oxygen concentration and a controller to manage gas supply in stages, ensuring the carbon dioxide concentration is maintained within a desired range by adjusting the amount of low oxygen concentration air supplied, even if the initial carbon dioxide concentration is low, by changing the gas supply amount based on the carbon dioxide concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gas supply operation is delayed until carbon dioxide concentration reaches a predetermined starting concentration, then the carbon dioxide concentration can be maintained at target levels, but the gas supply operation does not start promptly when initial carbon dioxide amount is small, causing plants to lose freshness

Engineering Contradiction:
Improvecarbon dioxide concentration control reliabilityVSAvoidtime delay in gas supply operation start
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The gas supply device is configured to dynamically adjust the amount of gas supply in multiple stages based on real-time carbon dioxide concentration measurements. The controller modifies the gas supply rate according to whether the concentration is below, within, or above the reference range, enabling the system to respond adaptively to changing conditions rather than operating statically

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller continuously monitors the carbon dioxide concentration in the storage and uses this feedback information to regulate the gas supply device. When concentration falls below the reference range, the controller increases gas supply to restore it, creating a closed-loop control system that ensures reliable concentration maintenance

Inventive Principle:
Principle #23Feedback

2Productivity

If the gas supply amount is increased to quickly raise carbon dioxide concentration, then the carbon dioxide concentration increases rapidly, but the oxygen concentration cannot be effectively reduced, affecting plant freshness

Engineering Contradiction:
Improvecarbon dioxide concentration increase rateVSAvoidoxygen concentration reduction
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts gas supply in multiple stages based on concentration measurements. When carbon dioxide concentration is below the reference range, the controller increases gas supply to rapidly raise concentration. When concentration reaches the reference range, the controller reduces gas supply to maintain it, thereby dynamically balancing the trade-off between increasing carbon dioxide concentration and reducing oxygen concentration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes the gas supply parameter (amount of gas supplied) based on the measured carbon dioxide concentration. By adjusting this parameter in response to concentration levels, the system achieves both rapid concentration increase when needed and effective oxygen reduction when concentration is sufficient

Inventive Principle:
Principle #35Parameter changes

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 ensures the carbon dioxide concentration is effectively controlled within a desired range, preventing plant freshness loss by initiating the gas supply operation promptly, even with low initial carbon dioxide levels, thereby maintaining optimal storage conditions.

Implementation Method 1

a gas supply device (30) that performs a gas supply operation for supplying low oxygen concentration air that is produced through reduction of oxygen from outside air

Methodology Applied
Scientific EffectOxygen reduction:

Implementation Method 2

if the carbon dioxide concentration of the inside air reaches a resuming concentration which is higher than the target carbon dioxide concentration through the breathing of the plants

Methodology Applied
Scientific EffectBreathing (respiration):

Data Source

PatentEP3751222B1Inside air control apparatus and container refrigeration apparatus equipped with the same
Publication Date: 2023.08.09 DAIKIN INDUSTRIES LTD
  • EP3751222B1 patent drawingFigure 1
  • EP3751222B1 patent drawingFigure 2
  • EP3751222B1 patent drawingFigure 3

AI summary

An inside air control apparatus (60) includes: a gas supply device (30) that performs a gas supply operation for supplying low oxygen concentration air into a container (11); and a controller (55) that controls an operation of the gas supply device (30) so that the inside air has desired composition. The controller (55) is configured to be able to execute, if an oxygen concentration of the inside air is higher than a target oxygen concentration, a carbon dioxide concentration controlling operation for controlling composition of the inside air to be desired composition by causing the gas supply device (30) to perform the gas supply operation, while allowing the gas supply device (30) to change the amount of gas supply such that the carbon dioxide concentration of the inside air falls within a predetermined reference concentration range.