Controlled Atmosphere System Startup Energy Optimization

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Solution Overview

Problem

Controlled atmosphere systems struggle to efficiently reach desired oxygen and carbon dioxide concentrations during the initial startup phase, especially when cargo has a low respiration rate or high oxygen leakage, leading to energy inefficiencies and potential shelf life issues for perishable goods.

Innovation Solution

The system employs an air compressor with ON and OFF states to allow or prevent ambient air entry, using a controller to calculate atmosphere change rates and maintain the compressor in the OFF state until desired concentrations are reached, then switching to an ON state to supply nitrogen at specific purity levels as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the air compressor is kept in the OFF state during initial startup phase, then energy consumption is reduced, but the atmosphere may not reach the desired set point

Engineering Contradiction:

Improvecompressor energy consumptionVSAvoidatmosphere set point achievement

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The controller continuously monitors the atmosphere change rate and compares it against the rate needed to reach the desired set point. This feedback mechanism allows the system to dynamically adjust compressor operation based on actual atmospheric conditions, ensuring energy efficiency when the cargo's respiration is sufficient while guaranteeing set point achievement when additional nitrogen injection is required.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system transitions from a static compressor operation mode to a dynamic one where the compressor state (ON/OFF) changes based on real-time atmospheric conditions. The controller calculates the atmosphere change rate and adjusts the compressor operation accordingly, making the system adaptable to varying cargo respiration rates and leakage conditions during the initial startup phase.

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If the air compressor is frequently switched between ON and OFF states, then energy efficiency is improved, but control complexity increases

Engineering Contradiction:

Improvecompressor energy consumptionVSAvoidcontroller logic complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The controller performs preliminary calculation of the atmosphere change rate and predicts whether the desired set point will be reached with the compressor in the OFF state. This preliminary assessment allows the system to make informed decisions about compressor operation before actually switching states, simplifying the control logic by avoiding complex real-time decision-making during frequent transitions.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If nitrogen is supplied continuously at high purity levels, then the desired atmosphere is achieved quickly, but energy consumption and nitrogen usage increase

Engineering Contradiction:

Improveatmosphere set point achievementVSAvoidcompressor and nitrogen supply energy consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system changes the nitrogen supply parameter dynamically by adjusting the compressor operation state (ON/OFF) based on the calculated atmosphere change rate. Instead of continuous high-purity nitrogen supply, the system varies the nitrogen injection level, using high purity only when necessary to reach the desired set point, thereby reducing overall energy consumption and nitrogen usage while maintaining reliable atmosphere control.

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 approach allows for energy savings by minimizing compressor usage while ensuring desired atmosphere conditions are met, effectively prolonging the shelf life of perishable goods during transportation.

Implementation Method 1

an air compressor having an ON state to allow ambient air outside of the interior space into the interior space and an OFF state to prevent ambient air outside of the interior space into the interior space

Methodology Applied

Scientific EffectGas compression and flow control: Gas Compressor

Implementation Method 2

By controlling one or more atmospheric parameters within the transport unit, the rate of ripening of perishable cargo stored in the transport unit can be reduced

Methodology Applied

Scientific EffectRespiration: Aerobic Digestion

Data Source

PatentUS10905141B2Controlled atmosphere system and method for controlling the same

Publication Date: 2021.02.02 THERMO KING CORP

AI summary

A method for obtaining a desired atmosphere within an interior space during an initial startup phase of a CAS is provided. The method includes a controller starting the CAS while keeping the air compressor OFF. The method also includes the controller calculating an atmosphere change rate while the air compressor OFF, and determining whether the interior space can reach a desired atmosphere set point with the air compressor OFF based on the atmosphere change rate. Further, the method includes the controller maintaining the air compressor OFF until the interior space reaches the desired atmosphere set point when the controller determines that the interior space can reach the desired atmosphere set point with the air compressor OFF, and switching the air compressor ON when the controller determines that the interior space cannot reach the desired atmosphere set point with the air compressor OFF.