Flexible Bladder Source Storage for Hydrogen Filling
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Solution Overview
Problem
Existing hydrogen tank filling stations require large source storages and complex valve systems due to the need for high-pressure compressors and successive balancing at increasingly high pressures, which increases the number of storages and mechanical complexity, and results in inefficient gas transfer and heat management.
Innovation Solution
The use of source storage with a rigid exterior wall and a flexible sealing wall allows for isobaric filling and pressure control through a liquid transfer circuit, eliminating the need for cascade fills and reducing storage requirements, while maintaining constant gas temperature for efficient heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-pressure compressors with very high instantaneous electrical power are used for direct filling, then filling speed is improved, but equipment cost and power requirements worsen
Solution Approach 1:
The filling process is segmented into multiple stages using a cascade system with storage tanks at different pressure levels (e.g., 200 bar, 500 bar, 800 bar). Gas is transferred sequentially from lower to higher pressure stages, avoiding the need for a single high-power compressor to achieve all pressure levels at once.
Solution Approach 2:
Gas is pre-compressed to intermediate pressure levels and stored in buffer tanks before final transfer to the vehicle tank. This preliminary compression at lower power levels allows the final high-pressure filling to be achieved through pressure equalization rather than direct high-power compression.
2Productivity
If cascade filling with multiple storage tanks at different pressures is used, then filling speed is improved, but the number of source storages and device complexity worsen
Solution Approach 1:
The system uses a flexible bladder inside the storage tank that dynamically adjusts its volume based on the pressure differential between the storage tank and the vehicle tank. As gas is transferred, the bladder contracts, automatically maintaining pressure equilibrium and eliminating the need for complex valve systems to control multiple fixed-pressure tanks.
Solution Approach 2:
The invention changes the parameter of storage tank flexibility by introducing a deformable bladder that can change volume. This allows a single storage tank to function effectively at multiple pressure levels by adjusting its internal volume, replacing the need for multiple fixed-pressure storage tanks.
3Productivity
If multiple successive balancings at increasingly high pressures are carried out, then complete filling is achieved, but the complexity of the valve system worsens
Solution Approach 1:
The flexible bladder system is self-regulating and automatically performs the multiple balancing operations needed for complete filling. The bladder's elastic properties cause it to expand and contract in response to pressure differences, automatically controlling the gas flow and eliminating the need for externally controlled complex valve systems.
4Quantity of substance
If large quantities of storage at high pressures are installed in the station, then gas availability is improved, but the volume and cost of source storages worsen
Solution Approach 1:
By changing from rigid fixed-volume tanks to a flexible bladder system, the same mass of gas can be stored at variable volumes depending on the pressure level. The bladder contracts as pressure increases, allowing more efficient use of storage space and reducing the overall volume required for the same gas capacity.
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 solution reduces the number of source storages needed, minimizes pressure variations, and simplifies the design of heat exchangers, achieving efficient and cost-effective hydrogen filling with reduced mechanical fatigue and gas storage volumes.
Implementation Method 1
the volume located between the flexible wall and the outer wall being connected to a liquid transfer circuit in the source storage, for filling or withdrawing liquid from the source storage and controlling the pressure in the storage during filling and/or withdrawal of fuel gas
Implementation Method 2
the at least one source storage comprises a rigid exterior wall and a flexible wall of sealing arranged inside the volume delimited by the rigid exterior wall, the flexible wall delimiting a storage volume for the fuel gas
Data Source
Figure 1~2
AI summary
The invention relates to a station (1) and method for filling a tank (7) with a fuel gas. Said station includes at least one fuel gas source store (3) and a gas transfer system (8) having a first upstream end connected to the source store(s) (3) and a second downstream end that is in fluid communication with the tank (7). The gas transfer system (8) includes at least one control valve (9, 10), characterized in that the at least one source store (3) includes a rigid outer wall and a flexible sealing wall (2) that is arranged inside the space defined by the rigid outer wall. The flexible wall (2) defines a storage space for the fuel gas. The first upstream end of the system (8) is connected to the storage space defined by the flexible wall (2). The at least one control valve is also characterized in that the space located between the flexible wall (2) and the outer wall is connected to a system (12, 13) for transferring liquid into the source store (3) in order to fill or extract the liquid in the source store (3) and control the pressure in the store (3) when filling and/or extracting fuel gas within the sealing wall (2).