Cryogenic Temperature Control With Two-Mode Cryogen Flow Switching
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Solution Overview
Problem
Conventional cryogenic temperature control systems for air conditioning and refrigeration are complex, inflexible, and inefficient, leading to high fuel consumption and potential shutdowns, especially when used in vehicles for transportation.
Innovation Solution
A cryogenic temperature control apparatus with a valve assembly and controller that adjusts the flow rate of cryogen between two modes to optimize temperature control, reducing fuel consumption and improving flexibility by limiting operation time in high-capacity cooling modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex control system is used to regulate temperature at set point, then temperature control precision is improved, but device complexity and fuel consumption increase
Solution Approach 1:
The control system is segmented into discrete operational modes (high-capacity cooling mode, low-capacity cooling mode, and heating mode) rather than using a continuous complex control algorithm. The valve assembly is segmented into discrete positions (first position for high flow rate, second position for low flow rate) that correspond to these modes, simplifying the control architecture while maintaining effective temperature regulation.
Solution Approach 2:
The system dynamically transitions between different operational modes based on real-time temperature conditions. The controller monitors the air-conditioned space temperature and automatically switches between high-capacity and low-capacity cooling modes, or to heating mode when needed, allowing the system to adapt its behavior to current conditions without requiring complex predictive algorithms.
2Productivity
If high flow rate of cryogen is delivered continuously, then cooling capacity is improved, but cryogen consumption and fuel usage increase
Solution Approach 1:
The system employs periodic action by alternating between high-capacity cooling mode and low-capacity cooling mode based on temperature conditions. Rather than continuously operating at high flow rate, the valve assembly periodically switches between first and second positions, delivering high cryogen flow only when the air-conditioned space temperature exceeds the first threshold, and reducing flow when temperature is within acceptable ranges, thereby conserving cryogen while maintaining cooling effectiveness.
Solution Approach 2:
The system changes the flow rate parameter of cryogen based on temperature conditions. The valve assembly adjusts the cryogen flow rate from a first flow rate (high capacity) to a second flow rate (low capacity) as the air-conditioned space temperature approaches the set point, optimizing the balance between cooling capacity and cryogen consumption through parameter adjustment rather than maintaining a constant high flow rate.
3Reliability
If the control apparatus operates in high-capacity mode for extended periods, then temperature control effectiveness is improved, but system reliability decreases due to fuel depletion
Solution Approach 1:
The system applies partial action by using high-capacity cooling mode only when necessary (when temperature exceeds the first threshold), rather than continuously. The low-capacity cooling mode provides sufficient cooling when temperature is closer to the set point, reducing the overall cryogen consumption and extending operation duration without compromising temperature control effectiveness. This partial use of high-capacity mode prevents fuel depletion while maintaining reliability.
4Device complexity
If a simple control mode is used, then device complexity is reduced, but adaptability to varying temperature conditions deteriorates
Solution Approach 1:
The valve assembly and control system are designed with multi-functionality, serving multiple purposes: high-capacity cooling mode for rapid temperature reduction, low-capacity cooling mode for maintenance cooling, and heating mode for temperature recovery. This universal design allows a single control apparatus to handle diverse temperature control scenarios (cooling, maintenance, and heating) without requiring multiple separate systems, thereby maintaining adaptability while keeping the device relatively simple.
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 solution effectively conserves cryogen, reduces fuel consumption, and enhances the flexibility of temperature control systems, preventing shutdowns and maintaining efficient operation across varying conditions.
Implementation Method 1
Relatively warm air is passed across the evaporator coil and is cooled by the evaporator coil
Implementation Method 2
The warm air heats and vaporizes the cryogen in the evaporator coil
Data Source
AI summary
A method of temperature control in a cryogenic temperature control apparatus. The method includes operating the cryogenic temperature control apparatus in a first mode, and delivering a first flow rate of cryogen from a storage tank to an evaporator coil in the first mode. The cryogenic temperature control apparatus is operated in a second mode after operating the cryogenic temperature control apparatus in the first mode for a predetermined time duration. A second flow rate of cryogen that is lower than the first flow rate is delivered to the evaporator coil in the second mode.