Portable Cascade Cooling Unit for Ultra-Low Transport Reliability
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Solution Overview
Problem
Current portable cooling units are unreliable for transporting highly temperature-sensitive goods due to limited cooling capacity, inability to maintain temperatures below 70K, and malfunctions during transport and varying ambient conditions, especially when inclined.
Innovation Solution
A portable cooling unit equipped with a multi-stage cascade refrigeration system, suspension, movement delimiting, impact protection, lubrication, and monitoring systems to maintain temperatures below 70K, ensuring reliable operation during transport and varying orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If passive cooling by dry ice or liquid nitrogen is used, then portability is achieved, but reliability deteriorates due to limited supply dissipation and inability to maintain temperature over long periods
Solution Approach 1:
The patent replaces passive cooling methods (dry ice, liquid nitrogen) with an active mechanical refrigeration system consisting of a compressor, condenser, expansion valve, and evaporator. This mechanical substitution enables reliable active cooling that can maintain temperatures below -70°C indefinitely, resolving the reliability issue while preserving portability through compact design.
Solution Approach 2:
The invention changes the operating parameters of the refrigeration system to achieve temperatures below -70°C by optimizing the refrigerant cycle, using appropriate refrigerants, and designing the evaporator and expansion valve to operate efficiently at ultra-low temperatures. This parameter optimization enables the system to reliably maintain required temperatures during transport.
2Ease of operation
If Stirling cooling systems are used, then portability is achieved, but cooling capacity deteriorates preventing fast recovery after door opening
Solution Approach 1:
The patent replaces the Stirling cooling system with a vapor-compression refrigeration system that provides superior cooling capacity. The compressor-driven system can rapidly remove heat after door openings, achieving fast temperature recovery that the Stirling system cannot provide, while maintaining portability through compact component design.
3Power
If stationary cooling units are used, then cooling capacity is sufficient, but adaptability deteriorates due to inability to operate during transport and under varying ambient conditions
Solution Approach 1:
The patent segments the refrigeration system into modular, portable components including a compact compressor, condenser, expansion valve, and evaporator that can function independently during transport. This segmentation enables the system to adapt to varying ambient conditions and orientations while maintaining sufficient cooling capacity, unlike fixed stationary systems.
Solution Approach 2:
The invention designs the refrigeration system to dynamically adapt to changing operating conditions during transport, including varying ambient temperatures, pressures, and orientations. The system maintains performance through dynamic refrigerant flow control and compact component design that accommodates movement and orientation changes.
4Power
If temperatures below 70K below ambient are required, then cooling power must increase, but system complexity and reliability under transport conditions worsen
Solution Approach 1:
The patent achieves high cooling power through a cascade refrigeration system segmented into two independent cycles: a high-temperature cycle (R134a) and a low-temperature cycle (R23). Each cycle operates at optimized parameters, with the high-temperature cycle condensing heat from the low-temperature cycle. This segmentation enables achieving temperatures below -70°C while managing system complexity through modular design.
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 portable cooling unit effectively maintains low temperatures, prevents malfunctions, and ensures safe transport of temperature-sensitive goods by providing sufficient cooling power and protection against mechanical stress and malfunctions.
Implementation Method 1
a multi-stage cascade refrigeration system adapted to operate during transport of the portable cooling unit and to cool down to and maintain temperatures of more than 70 K, preferably more than 120 K, below ambient temperature
Implementation Method 2
a suspension system adapted and arranged to serve as elastic bearing for the multi-stage cascade refrigeration system and/or for components of the multi-stage cascade refrigeration system
Implementation Method 3
an impact protection system adapted and arranged to dampen collisions between the multi-stage cascade refrigeration system and other parts of the portable cooling unit, and/or between the components of the multi-stage cascade refrigeration system
Implementation Method 4
a lubrication system facilitating lubrication of the components of the multi-stage cascade refrigeration system for inclinations of the portable cooling unit of at least 10°, preferably of more than 20°, out of horizontal orientation
Data Source
Figure 1~2
Figure 3~4
AI summary
Portable cooling unit (1) for transporting temperature-sensitive goods while maintaining a desired cooling temperature, said portable cooling unit (1) comprising a multi-stage cascade refrigeration system (2) adapted to operate during transport of the portable cooling unit (1) and to cool down to and maintain temperatures of more than 70 K below ambient temperature, a suspension system (3) adapted and arranged to serve as elastic bearing for the multi-stage cascade refrigeration system (2) and/or for components of the multi-stage cascade refrigeration system (2), a movement delimiting system (4) adapted and arranged to restrict movement of the multi-stage cascade refrigeration system (2) and/or the components of the multi-stage cascade refrigeration system (2), an impact protection system (5) adapted and arranged to dampen collisions between the multi-stage cascade refrigeration system (2) and other parts of the portable cooling unit (1), and/or between the components of the multi-stage cascade refrigeration system (2), a lubrication system (6) facilitating lubrication of the components of the multi-stage cascade refrigeration system (2) for inclinations of at least 10° out of horizontal orientation of the portable cooling unit (1), and a monitoring system (7) adapted to generate an alarm signal upon malfunction of the portable cooling unit (1).