Dynamic controlled atmosphere method and apparatus
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Solution Overview
Problem
Existing dynamic controlled atmosphere (DCA) methods for fruit and vegetable storage require additional and expensive equipment, such as gas analyzers with high precision, and often provide inaccurate oxygen set-point levels due to limited sampling, leading to potential fruit damage.
Innovation Solution
A method that determines optimal oxygen partial pressure and temperature based solely on carbon dioxide partial pressure measurements, using equations that incorporate factors like CO2 release rate and anaerobic metabolism, without the need for additional sensors or complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chlorophyll sensors are installed inside storage rooms to monitor LOL in real-time, then the precision of oxygen level detection is improved, but the cost of storage rooms increases and device complexity increases
Solution Approach 1:
The patent uses carbon dioxide partial pressure as an intermediary parameter to indirectly determine oxygen levels and LOL. Instead of directly measuring oxygen with complex chlorophyll sensors, the system measures CO2 partial pressure which correlates with fruit metabolism and oxygen consumption, providing a simpler indirect measurement approach that avoids direct oxygen sensing complexity
Solution Approach 2:
The patent replaces the mechanical/optical sensing system (chlorophyll fluorescence sensors) with a gas analysis system that measures CO2 partial pressure. This substitution uses chemical composition analysis instead of optical property measurement, simplifying the sensing mechanism while maintaining measurement capability for determining oxygen levels
2Device complexity
If limited samples are monitored for LOL determination in each storage room, then the device complexity is reduced, but the reliability of oxygen set-point determination deteriorates
Solution Approach 1:
The patent employs a distributed sensing approach where the storage room environment itself provides the measurement data through CO2 partial pressure monitoring. The fruit population collectively contributes to the CO2 concentration, which reflects the aggregate metabolic state and oxygen consumption of all fruits in the room, enabling reliable LOL determination without complex sampling systems
Solution Approach 2:
The CO2 partial pressure measurement system serves multiple functions simultaneously: it monitors fruit metabolism rate, determines oxygen consumption patterns, identifies LOL conditions, and guides oxygen set-point adjustments. This single measurement parameter provides universal information for all control decisions, eliminating the need for separate monitoring systems for different parameters
3Measurement precision
If high precision gas analyzers are installed to enable DCA-RQ measurements, then the measurement precision is improved, but the cost of storage rooms increases
Solution Approach 1:
The patent extracts and utilizes only the necessary measurement component (CO2 partial pressure) from the complex DCA-RQ system. By focusing solely on CO2 measurement rather than implementing full respiratory quotient analysis with multiple gas measurements, the system achieves the essential functionality of monitoring fruit metabolism and determining oxygen levels without requiring the complete high-precision gas analysis infrastructure
Solution Approach 2:
The patent employs a simpler, more economical measurement approach using standard CO2 sensors rather than expensive high-precision gas analyzers. This cost-effective sensing solution provides sufficient accuracy for determining CO2 partial pressure and inferring oxygen levels, making the system economically viable without requiring premium instrumentation
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 approach reduces costs, ensures precise oxygen and temperature settings, avoids fruit damage, and extends shelf life by inducing anaerobic metabolism, producing compounds that suppress ethylene biosynthesis and enhance aroma, while being energy-efficient.
Implementation Method 1
a gas analyser (306), the apparatus being configured to measure a carbon dioxide partial pressure inside the storage room (300)
Data Source
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AI summary
The present invention relates to a method and an apparatus for controlling the atmosphere in a space, in particular, the present invention relates to a method and apparatus for controlling the atmosphere in a closable space at least partially filled with agricultural or horticultural products. In the method according to the invention an optimal oxygen partial pressure and / or an optimal temperature for storing produce is determined based on measurements of solely a carbon dioxide partial pressure.