Refrigeration unit for container
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Solution Overview
Problem
Existing container refrigeration apparatuses for marine transportation require large air compressors and separate carbon dioxide bottles to achieve high-purity nitrogen and controlled carbon dioxide concentrations, leading to increased weight and cost.
Innovation Solution
A container refrigeration apparatus using nitrogen-adsorbing adsorbents like zeolite for producing a gas mixture with high nitrogen concentration, reducing the need for high pressurization pressure and eliminating the need for a carbon dioxide bottle by allowing plants to respire and release carbon dioxide naturally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-purity nitrogen gas is produced using a membrane separator, then oxygen concentration control is improved, but apparatus weight increases due to large air compressor
Solution Approach 1:
The invention changes the operating parameters of the air compressor from high pressure (827.6 kPa) to low pressure (100-200 kPa) by using adsorbent-based nitrogen separation instead of membrane separation, thereby reducing compressor size and apparatus weight while maintaining oxygen concentration control capability
Solution Approach 2:
The invention replaces the membrane separator-based mechanical system with an adsorbent-based separation system, which eliminates the need for high-pressure compression and associated heating equipment, thereby reducing apparatus weight and complexity
2Measurement precision
If high-purity nitrogen gas is produced using a membrane separator, then oxygen concentration control is improved, but apparatus weight increases due to air heater
Solution Approach 1:
The invention replaces the thermal field system (air heater) with a chemical adsorption system, where nitrogen is separated from air through adsorbent materials at ambient or refrigeration temperatures, eliminating the need for heating equipment and reducing apparatus weight
3Measurement precision
If carbon dioxide bottles are provided to control carbon dioxide concentration, then carbon dioxide concentration control is improved, but apparatus weight increases
Solution Approach 1:
The invention enables the container atmosphere to self-regulate carbon dioxide concentration through plant respiration, which naturally releases carbon dioxide into the container, eliminating the need for external carbon dioxide supply equipment and reducing apparatus weight
4Weight of moving object
If adsorbent system is used to produce nitrogen gas, then apparatus weight is reduced, but nitrogen concentration may be lower than 99%
Solution Approach 1:
The invention changes the nitrogen concentration parameter from requiring 99% purity to accepting 90-95% purity, which enables the use of adsorbent-based separation at low pressure instead of membrane separation at high pressure, thereby reducing apparatus weight while maintaining sufficient oxygen concentration control for plant preservation
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 apparatus reduces overall weight and cost by using a smaller compressor and eliminating the need for additional equipment, while maintaining controlled oxygen and carbon dioxide concentrations within the container.
Implementation Method 1
first and second adsorbers (34) and (35) each provided with an adsorbent adsorbing nitrogen in the air
Implementation Method 2
a pressurization portion (31a) which pressurizes one of the first and second adsorbers (34) and (35) by supplying the one adsorber with the air
Implementation Method 3
a depressurization portion (31b) which depressurizes the other of the first and second adsorbers (34) and (35) by sucking the air from the other adsorber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed herein a technique for producing a gas mixture for controlling an oxygen concentration in the interior of a container while reducing the overall weight of the apparatus. For this purpose, a gas mixture supply device is provided for a container refrigeration apparatus. The gas mixture supply device is provided with adsorption columns (34, 35). If one of the first and second adsorption columns (34) and (35) is supplied with air, the adsorption columns (34, 35) are pressurized, and nitrogen in the air is adsorbed onto an adsorbent. If air is sucked from the other of the first and second adsorption columns (34) and (35), the adsorption columns (34, 35) are depressurized, and nitrogen adsorbed onto the adsorbent is desorbed. A gas mixture including the nitrogen desorbed from the adsorbent is supplied to the interior of a container (11).