Cryogenic Cooling System with Vacuum Pump and Condenser Recirculation
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Solution Overview
Problem
Existing cooling systems using cryogenic cooling media in tanks require frequent refilling, leading to logistical and financial challenges, especially when high consumption rates are involved, and existing Brayton cooling circuits are complex and costly to operate.
Innovation Solution
A method utilizing a cryostat with a vacuum pump to maintain low pressure, where the gaseous cooling medium is compressed, reliquefied, and expanded through a throttle element, with a heat exchanger to preheat the cooling medium before the vacuum pump, and a condenser using the Linde principle to efficiently manage the cooling medium's temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cryogenic cooling medium is stored in tanks, then cooling function is provided, but frequent refilling is required leading to logistical effort and costs
Solution Approach 1:
The system changes the pressure parameter of the cooling medium by using a vacuum pump to maintain low pressure (vacuum) in the cryostat. This parameter change allows the cooling medium to be continuously withdrawn from the gas phase, reliquefied in a condenser, and fed back to the liquid phase without requiring tank refilling, thus resolving the contradiction between operational continuity and refilling time
Solution Approach 2:
The system implements self-service by automatically reliquefying the withdrawn gaseous cooling medium through a condenser and feeding it back to the cryostat. This closed-loop process eliminates the need for external refilling operations, allowing the system to sustain its own cooling function indefinitely without logistical intervention
2Temperature
If vacuum pump is used to reduce pressure in cryostat, then cooling medium temperature is reduced and subcooling is achieved, but energy consumption increases
Solution Approach 1:
The system uses feedback by continuously monitoring the cooling medium temperature and pressure conditions, and automatically adjusting the vacuum pump operation and cooling medium circulation accordingly. This feedback mechanism ensures the vacuum pump operates only when and to the extent needed to maintain the required temperature, minimizing energy consumption while achieving the desired subcooling effect
Solution Approach 2:
The system employs a composite approach by combining the vacuum pump with a condenser and throttle device to create an integrated temperature control system. The vacuum pump creates low pressure for subcooling, while the condenser reliquefies the gas and the throttle device controls pressure, working together to achieve temperature reduction with optimized energy usage
3Reliability
If cooling medium is continuously circulated through condenser and vacuum pump, then subcooling is maintained, but system complexity increases
Solution Approach 1:
The system merges multiple functions into integrated components: the condenser serves both to reliquefy the withdrawn gas and to act as a heat exchanger, while the throttle device simultaneously controls pressure and facilitates the liquid-gas phase transition. This merging reduces the number of separate components needed, maintaining reliable subcooling while limiting system complexity
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 provides a cost-effective and efficient cooling method by maintaining low temperatures within the cryostat, reducing evaporation losses, and allowing for continuous operation without the need for frequent tank refilling, while also optimizing the use of heat exchange to manage the cooling medium's temperature effectively.
Implementation Method 1
the pressure in a gas phase above the cooling bath is reduced using a vacuum pump. Due to the resulting temperature reduction, the cooling bath can then be used to subcool cooling medium at a higher pressure
Implementation Method 2
the gaseous cooling medium extracted by the vacuum pump can then be re-liquefied
Implementation Method 3
the withdrawn gaseous cooling medium is fed from the cryostat to a condenser and re-liquefied
Implementation Method 4
the re-liquefied cooling medium is expanded at a throttle device to a pressure prevailing in the cryostat
Implementation Method 5
at least a partial flow of the cooling medium withdrawn from the gas phase in the cryostat is brought into thermal contact with the cooling medium in the condenser upstream of the vacuum pump
Implementation Method 6
a cryogenic cooling medium, which is present in a cryostat in a liquid phase and in a gas phase, is brought into thermal contact with a consumer
Data Source
Figure 1
AI summary
In a method for cooling a consumer by means of a cryogenic cooling medium, thermal contact of the cooling medium with the consumer is established in a cryostat. The cooling medium in the cryostat is brought to a low temperature by sucking gaseous cooling medium away from the cryostat using a vacuum pump. The cooling medium conveyed by the vacuum pump is reliquefied in a condenser and is expanded at a throttle element to the pressure prevailing in the cryostat. In accordance with the invention, the cooling medium pumped out of the cryostat is brought into thermal contact with the cooling medium in the condenser upstream of the vacuum pump. Efficiency of the cooling process is significantly improved in this way.