Cryogenic Tank Pressure Control via Segmented Valves
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Solution Overview
Problem
Existing cryogenic pressure tanks face challenges in maintaining a stable and efficient hydrogen supply at supercritical pressures due to complex pressure control requirements, which are exacerbated by large pressure fluctuations and limited heat management, leading to suboptimal hydrogen usage and potential pressure increases.
Innovation Solution
A simplified 'black-and-white' mode of operation for the tank pressure control valve, where it remains either fully open or closed for extended periods, combined with a pressure control unit in the supply line, ensures a continuous hydrogen supply and manages pressure fluctuations, allowing for longer hydrogen usage without exceeding design limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If continuous pressure control is implemented in cryogenic pressure tanks, then hydrogen supply stability is improved, but control system complexity increases
Solution Approach 1:
The control system is segmented into two independent components: a tank pressure control valve for coarse pressure regulation and a supply line pressure control valve for fine pressure control. This segmentation allows each valve to operate independently with simplified control logic, while collectively achieving stable hydrogen supply pressure.
Solution Approach 2:
The supply line pressure control valve acts as an intermediary between the tank pressure control system and the consumer. It decouples the tank pressure fluctuations from the consumer supply pressure, allowing the consumer to receive stable pressure regardless of tank pressure variations.
2Stability of the object's composition
If tank pressure control valve is frequently adjusted, then pressure stability is improved, but heat input into the tank increases
Solution Approach 1:
By separating tank pressure control from supply pressure control, the system allows the tank pressure control valve to remain in stable positions (fully open or closed) for extended periods, minimizing frequent adjustments and associated heat input, while the supply line pressure control valve handles fine pressure regulation.
Solution Approach 2:
The system allows tank pressure to fluctuate within a wider range than traditionally controlled, using partial pressure control at the tank level combined with full pressure control at the supply line level. This reduces the need for frequent tank pressure valve adjustments.
3Stress or pressure
If hydrogen is withdrawn at high pressure, then consumer pressure requirements are met, but tank pressure fluctuations increase
Solution Approach 1:
The supply line pressure control valve serves as an intermediary that buffers tank pressure fluctuations. It maintains stable consumer pressure by compensating for tank pressure variations, allowing high-pressure hydrogen withdrawal without transmitting full fluctuation amplitude to the consumer.
Solution Approach 2:
The dual-valve segmentation allows the tank pressure control valve to manage overall pressure levels while the supply line pressure control valve isolates consumer pressure from tank pressure fluctuations, enabling high-pressure supply with reduced fluctuation transmission.
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 for a sustained hydrogen supply at required pressures, increasing the usable hydrogen mass and reducing the complexity of control systems, while minimizing heat input and pressure increases, thus enhancing the operational efficiency and capacity of cryogenic pressure tanks.
Implementation Method 1
heating the hydrogen from the cryo-pressure tank and, after flowing through the heat exchanger
Implementation Method 2
a pressure control valve and a branch line branching off from a supply line leading to the consumer
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an operating method for a cryopressure tank, wherein cryogenic hydrogen may be stored for supplying a consumer, particularly an internal combustion engine and/or a fuel cell of a motor vehicle under supercritical pressure at (13) bar or more, wherein, in order to compensate the loss of pressure resulting from the removal of hydrogen from the cryopressure tank, removed hydrogen that has been heated in a heat exchanger is conveyed to a heat exchanger present in the cryopressure tank via a tank pressure regulation valve and a branch line branching off of a supply line leading to the consumer and, after flowing through the heat exchanger, is conducted into the supply line downstream of the branch of the branch line. Over a period of time significantly exceeding the cycles of a conventional cycle valve, either the removed amount of hydrogen is guided without limitation into the heat exchanger provided in the cryopressure tank, the tank pressure control valve being completely open, or no return of heated hydrogen into the heat exchanger provided in the cryopressure tank occurs. A pressure control unit is provided in the supply line downstream of the branch, which ensures that, in spite of changes to the pressure in the supply line caused upstream of the pressure control unit by switching the tank pressure regulation valve, a sufficient and continuous supply of hydrogen to the consumer at the pressure required is guaranteed.