Rechargeable passive cooled refrigerated cargo box
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Solution Overview
Problem
Existing refrigerated cargo containers face challenges in efficiently maintaining temperature control and energy usage, with active systems being more reliable but energy-intensive and passive systems being harder to control and requiring frequent material replacement.
Innovation Solution
A rechargeable passively cooled cargo container design featuring a thermally insulating exterior and conductive interior with a fluid circuit containing supercooled phase change materials, allowing for quick recharge and temperature regulation through a serpentine flowpath and sensor-controlled injection of supercooled fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active refrigeration systems are used, then temperature control reliability is improved, but energy usage increases
Solution Approach 1:
The system dynamically switches between passive cooling mode (using phase change materials in the fluid circuit) and active recharging mode (using the rechargeable battery and compressor). This dynamic operation allows the system to maintain reliable temperature control while minimizing energy consumption during the cooling phase, only activating energy-intensive components when needed for recharging.
Solution Approach 2:
The system utilizes phase change materials (PCM) in the fluid circuit that absorb and release thermal energy during phase transitions. During passive cooling, the PCM absorbs heat from the cargo as it melts, maintaining temperature without energy input. During recharging, the compressor condenses the refrigerant gas, releasing heat to the environment. These phase transitions enable reliable temperature control with minimal energy usage.
2Use of energy by moving object
If passive cooling systems are used, then energy usage is reduced, but control capability deteriorates
Solution Approach 1:
The system incorporates temperature sensors that continuously monitor the cargo compartment temperature and provide feedback to the control system. Based on this feedback, the microprocessor controls the recharge cycle timing, fluid circuit operation, and compressor activation. This feedback mechanism enables precise temperature control capability while maintaining passive cooling operation, resolving the contradiction between energy efficiency and control capability.
3Use of energy by moving object
If passive cooling systems are used, then energy usage is reduced, but operational complexity increases due to material replacement requirements
Solution Approach 1:
The system automatically manages its own cooling operation without requiring manual intervention for material replacement. The rechargeable battery powers the compressor and control systems, enabling automatic recharging of the phase change materials in the fluid circuit. The microprocessor controls the entire recharging process based on sensor feedback, eliminating the need for manual removal and replacement of cooling materials, thus maintaining energy efficiency while improving operational simplicity.
4Reliability
If rechargeable battery and fluid circuit are integrated, then temperature control is improved, but device complexity increases
Solution Approach 1:
The system merges the rechargeable battery, compressor, fluid circuit with phase change materials, and control system into an integrated refrigeration unit. The battery and compressor are positioned within the cargo compartment, the fluid circuit is embedded in the wall structure, and the control system coordinates all components. This integration improves temperature control reliability by ensuring coordinated operation of all components while managing complexity through unified system design and control.
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 design enhances temperature control and reduces energy usage by allowing for efficient recharge and prolonged cooling, while minimizing system complexity and weight through the use of high latent heat phase change materials.
Implementation Method 1
The alternative passive cooling utilizes a phase changing material, such as ice or dry ice, to effectively cool the cargo container throughout the shipping process
Implementation Method 2
minimizing system complexity and weight through the use of high latent heat phase change materials
Implementation Method 3
a plurality of exterior walls defining an exterior volume, each of the exterior walls being thermally insulating
Implementation Method 4
a plurality of interior walls define an interior volume within the plurality of exterior walls, each of the interior walls being thermally conductive
Implementation Method 5
at least one fluid circuit disposed between the plurality of exterior walls and the plurality of interior walls, the at least one fluid circuit including an inlet and an outlet and being configured to contain a super cooled fluid
Data Source
AI summary
A refrigerated cargo container includes multiple exterior walls defining an exterior volume. Each of the exterior walls is thermally insulating. The container also includes multiple interior walls that define an interior volume within exterior walls. Each of the interior walls is thermally conductive. At least one fluid circuit is disposed between the plurality of exterior walls and the plurality of interior walls. The at least one fluid circuit including an inlet and an outlet and are configured to contain a super cooled fluid.