Liquid Hydrogen Pressure-Building With Two-Stage Pumping
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Solution Overview
Problem
Existing hydrogen storage and delivery systems for vehicles face challenges in maintaining low pressure for storage while meeting high pressure requirements of onboard power systems, leading to inefficiencies and reliability issues due to cavitation and vapor lock, and requiring bulky, heavy mechanical pumps that increase thermal load and mass.
Innovation Solution
A multi-stage pressure building system with a hydrogen storage tank having a first portion for vapor and a second portion for liquid, using a first pump submerged in the liquid to boost pressure, a second pump outside the tank to achieve high pressure, and a heat exchanger to manage thermal energy, reducing heat leakage and pump size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a single high-pressure pump is used to deliver hydrogen from storage to power systems, then the pressure delivery requirement is met, but cavitation and vapor lock occur reducing reliability
Solution Approach 1:
The single high-pressure pumping function is segmented into two stages: a first pump that delivers liquid hydrogen from the storage tank to an intermediate pressure, and a second pump that delivers from intermediate pressure to the final high pressure required by power systems. This segmentation prevents cavitation and vapor lock by avoiding the need for a single pump to create extreme pressure differentials, thereby maintaining reliability while meeting delivery pressure requirements.
2Stress or pressure
If bulky mechanical pumps are used to build pressure, then pressure delivery is achieved, but system mass and thermal load increase
Solution Approach 1:
The system replaces traditional bulky mechanical pressure-building mechanisms with a two-stage pump architecture that uses optimized fluid dynamics and thermal management. The first pump operates in the cryogenic liquid hydrogen environment with minimized thermal coupling, while the second pump handles the intermediate to high pressure transition. This substitution reduces overall system mass compared to single-stage mechanical pumps while achieving the required storage and delivery pressures.
3Device complexity
If pumps are placed inside the storage tank to save space, then compactness is achieved, but thermal load on the cryogenic storage increases
Solution Approach 1:
The second pump, which handles the intermediate to high pressure transition, is extracted from the cryogenic storage tank environment and placed in a thermally isolated location. Only the first pump remains inside or directly coupled to the tank. This extraction removes the primary heat-generating pumping mechanism from the cryogenic environment, significantly reducing thermal load on the liquid hydrogen storage while maintaining system compactness through strategic spatial arrangement.
4Stress or pressure
If low pressure storage is used to reduce tank stress, then storage safety is improved, but pressure building to delivery requirements becomes more difficult
Solution Approach 1:
The pressure building process is segmented into two distinct stages with intermediate pressure as a transition point. The first pump handles the low-pressure-to-intermediate-pressure transition from the safe, low-stress storage tank, while the second pump handles the intermediate-to-high-pressure transition for power system delivery. This segmentation allows the storage tank to maintain low stress levels while still achieving the high delivery pressures required, managing complexity through functional decomposition.
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 system optimizes efficiency, reduces mass and volume, and enhances reliability by minimizing cavitation and vapor lock, allowing for compact, lightweight hydrogen delivery to power systems while maintaining sufficient pressure and temperature for vehicle operation.
Implementation Method 1
The first pump is to receive liquid hydrogen from the second portion of the inner volume when liquid hydrogen is stored in the hydrogen storage tank and to pump the liquid hydrogen out of the hydrogen storage tank to produce a low pressure flow of liquid hydrogen
Implementation Method 2
The second pump is to receive the low pressure flow of liquid hydrogen from the first pump and to produce a high pressure flow of liquid hydrogen
Implementation Method 3
The heat exchanger is to receive the high pressure flow of liquid hydrogen from the second pump and to provide a flow of hydrogen gas to a hydrogen-powered energy producing system
Data Source
AI summary
A system and method for hydrogen storage, and delivery. The system includes a hydrogen storage tank, a first pump disposed within the hydrogen storage tank, and a second pump disposed outside of the hydrogen storage tank. The hydrogen storage tank is to store gaseous hydrogen and liquid hydrogen. The first pump is to pump out liquid hydrogen out of the storage tank, producing a low pressure flow. The second pump is to receive this low pressure flow and produces a high pressure flow of liquid hydrogen. The system can also include a thermal device disposed within the hydrogen storage tank to heat gaseous hydrogen when a pressure within the hydrogen storage tank drops below a predetermined minimum pressure. The system can also include a heat exchanger to receive the high pressure flow of liquid hydrogen from the second pump.