Cascade Refrigeration Booster Line for Peak Cargo Cooling
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Solution Overview
Problem
Conventional refrigeration systems for vehicle cargo spaces are oversized due to being sized for peak demands, leading to inefficient use of cryogen and frequent refilling needs, as they are not optimized for normal operating conditions.
Innovation Solution
A cascade refrigeration system with a booster cooling line that expands and vents a portion of cryogenic refrigerant to the atmosphere during peak demands, while maintaining a closed loop circuit for continuous operation, allowing for additional cooling capacity without increasing system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the refrigeration system is sized to handle peak demand, then the cooling capacity during peak demand is sufficient, but the system size is larger than needed during normal operating conditions
Solution Approach 1:
The refrigeration system is segmented into two distinct circuits: a closed-loop vapor compression circuit for baseline cooling and an open-loop booster cooling line for peak demand. This segmentation allows each circuit to be optimized independently, with the booster line providing additional capacity only when needed without permanently increasing system size.
Solution Approach 2:
The system dynamically switches between closed-loop and open-loop modes based on cooling demand. The booster cooling line can be activated during peak demand periods (initial pull-down, door openings, defrost cycles) and deactivated during normal operation, allowing the system to adapt its capacity to actual needs rather than maintaining fixed oversized capacity.
2Power
If the refrigeration system is sized for peak demand, then the cooling capacity during peak demand is sufficient, but the cryogen storage duration is reduced due to frequent refilling
Solution Approach 1:
The booster cooling line provides partial cooling capacity only when needed for peak demands, rather than running continuously. This partial action approach allows the main closed-loop system to operate at its optimal, smaller size while the booster supplements capacity temporarily, thereby conserving cryogen and extending storage duration between refills.
Solution Approach 2:
The system recovers and condenses cryogen vapor in the closed-loop circuit, converting it back to liquid form for reuse. This recovery process reduces overall cryogen consumption compared to complete venting, extending the effective storage duration of the cryogen supply.
3Power
If conventional vapor compression systems are used, then the system can handle peak demand, but the system size is larger than needed for normal operation
Solution Approach 1:
The system segments the cooling function into a primary closed-loop vapor compression circuit and a supplemental open-loop booster line. This segmentation allows the main system to be sized for normal operation while the booster handles peak demands, avoiding the need for a single oversized complex system.
Solution Approach 2:
The booster cooling line serves multiple functions: it provides additional cooling capacity during peak demands, can operate independently if the closed-loop system fails, and can be used for rapid temperature reduction. This multi-functionality justifies the added complexity by providing versatile cooling solutions.
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 the refrigeration system to be sized for typical lower-capacity operating conditions, extending the duration of cryogen storage and reducing the need for frequent refills, while also minimizing emissions and costs.
Implementation Method 1
a booster cooling line configured to supplement the cooling capacity of the cascade refrigeration system by expanding and venting a portion of a cryogenic refrigerant to the atmosphere during peak demands
Implementation Method 2
a heat exchanger that cools the cargo space
Implementation Method 3
the condensed cryogenic refrigerant from the cascade heat exchanger
Data Source
AI summary
A temperature-controlled vehicle including a cascade refrigeration system having a booster cooling line configured to supplement the cooling capacity of the cascade refrigeration system by expanding and venting a portion of a cryogenic refrigerant to the atmosphere during peak demands while the cascade refrigeration system continues to operate.