Cryogenic Hydrogen Tank Cooling via Evaporated Gas Recovery
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Solution Overview
Problem
Existing hydrogen tank systems face inefficiencies in maintaining pressure and minimizing hydrogen loss during cryogenic hydrogen dispensing, as valuable cold is lost through heat exchangers and constant removal of hydrogen leads to pressure drops, necessitating venting or recycling, which is not optimal for regular operation.
Innovation Solution
A hydrogen tank system incorporating a cryopump system and heat exchanger that delivers a first stream of cryogenic hydrogen to an output line and uses a second stream to cool the system and components, with the cooled hydrogen being partially returned to the liquid hydrogen tank, optimizing heat dissipation and maintaining pressure equilibrium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a heat exchanger is used to maintain pressure in the storage tank by evaporating and returning cryogenic liquid, then pressure stability is improved, but valuable cold is lost to the ambient air
Solution Approach 1:
The patent recovers the cold energy that would otherwise be lost to the ambient air by using the evaporated cryogenic gas to cool the dispensing lines and components. The cold is not discarded but recovered and reused to pre-cool the system before dispensing, thereby maintaining pressure stability while minimizing cold loss.
Solution Approach 2:
The patent converts the harmful effect of heat input causing pressure rise into a beneficial cooling effect. The evaporated gas, which would normally be vented or used inefficiently, is instead utilized to cool the dispensing lines and components, turning a potential waste stream into a useful cooling resource.
2Reliability
If hydrogen is vented or recycled to prevent tank bursting when pressure rises above threshold, then safety is improved, but hydrogen loss or system complexity increases
Solution Approach 1:
The patent performs preliminary cooling of the dispensing lines and components using evaporated hydrogen before dispensing operations. This pre-cooling action reduces the overall heat load on the storage tank, thereby preventing excessive pressure rise and eliminating the need for venting or recycling operations.
Solution Approach 2:
The patent maintains continuous cooling of the dispensing system by continuously utilizing evaporated hydrogen from the storage tank. This continuous cooling action prevents pressure buildup over time, avoiding the need for intermittent venting or recycling operations.
3Temperature
If dispensing lines are pre-cooled by flushing with cryogenic media, then cooling effectiveness is improved, but the heated medium requires compression and cooling before discharge
Solution Approach 1:
The patent merges the cooling function with the dispensing function by using the same cryogenic hydrogen stream for both cooling the lines and subsequent dispensing. The cooling and dispensing operations are combined into a single integrated process, eliminating the need for separate cooling and dispensing systems.
Solution Approach 2:
The patent makes the dispensing system multi-functional by using the evaporated hydrogen for multiple purposes: cooling the dispensing lines, pre-cooling the dispensed hydrogen, and maintaining pressure in the storage tank. This universal use of the same hydrogen stream eliminates the need for dedicated cooling systems.
4Temperature
If cooling lines are used to withdraw cryogenic hydrogen from the storage tank, then cooling capability is improved, but pressure drop in the storage tank increases
Solution Approach 1:
The patent changes the operational parameters by using evaporated gas rather than liquid for cooling the dispensing lines. This parameter change (from liquid to gas phase cooling) reduces the withdrawal rate from the storage tank, thereby minimizing pressure drop while maintaining adequate cooling capability.
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 enables efficient cooling of the hydrogen tank system and refueling components, maximizing hydrogen density and mass flow, reducing losses, and allowing for high-density hydrogen refueling, while minimizing the need for complex and costly cryopumps, thus enhancing the efficiency and cost-effectiveness of hydrogen filling stations.
Implementation Method 1
a heat exchanger for cooling the cryopump system and/or an output stream of the cryopump system and/or the dispensing line by means of a second stream of cryogenic hydrogen
Implementation Method 2
a cryopump system for conveying a first stream of cryogenic hydrogen via a conveying line from the liquid hydrogen tank to the dispensing line
Data Source
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AI summary
A method (200) for dispensing cryogenic hydrogen from a hydrogen storage system (10) comprising a liquid hydrogen tank (12), a cryopumping system (16), and a dispensing line (14) is provided. The method includes conveying (202) an initial stream of cryogenic hydrogen via a conveying line (18) using the cryopumping system from the liquid hydrogen tank (12) to the dispensing line (14).The method (200) is characterized in that the method further comprises a withdrawal (204) of a second cryogenic stream of cryogenic hydrogen via a cooling line (22) from the liquid hydrogen tank (12), as well as a cooling (206) of the cryopump system (16) and/or an output stream of the cryopump system (16) and/or the output line (14) by means of the second stream of cryogenic hydrogen, and an at least partial return (208) of the second stream of hydrogen to the liquid hydrogen tank after cooling (206) of the cryopump system (16) and/or the output stream of the cryopump system and/or the output line.