Liquid Hydrogen Return Circuit for Tank Pressure Stability
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Solution Overview
Problem
Conventional liquid hydrogen systems fail to maintain appropriate internal pressure in hydrogen tanks during sudden increases in hydrogen consumption, leading to pump failure and inadequate hydrogen supply to engines.
Innovation Solution
A liquid hydrogen system with a return circuit, pressure sensors, and a controller to manage internal pressure by returning excess hydrogen gas to the tank, using a booster pump to reduce pressure resistance requirements and incorporating a pressure chamber to stabilize supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid hydrogen is extracted in large quantity from the hydrogen tank, then hydrogen consumption demand is met, but internal pressure of the hydrogen tank decreases excessively
Solution Approach 1:
A return circuit is introduced as an intermediary pathway that allows hydrogen gas to flow back from the supply circuit to the hydrogen tank. This mediator circuit enables pressure regulation by redirecting excess gas flow, thereby preventing excessive pressure drop in the main supply line while still meeting high hydrogen consumption demands.
Solution Approach 2:
The system implements feedback control by monitoring the internal pressure of the hydrogen tank and automatically adjusting the return circuit operation. When pressure drops below a reference level, the controller activates the return circuit to restore pressure, creating a closed-loop control system that maintains stable operating conditions during variable hydrogen consumption.
2Productivity
If internal pressure of hydrogen tank decreases excessively, then hydrogen extraction continues, but pump fails to discharge liquid hydrogen
Solution Approach 1:
The return circuit operates in advance to prevent the harmful condition of excessive pressure drop before it occurs. By continuously monitoring pressure and activating the return pathway when pressure approaches critical levels, the system counteracts the pressure reduction effect of high-rate extraction, thereby preventing pump failure before it happens.
Solution Approach 2:
The return circuit acts as a cushioning mechanism that absorbs the harmful effect of pressure drop. By providing an alternative pathway for hydrogen gas to return to the tank, the system creates a pressure buffer that protects the pump from operating under excessively low pressure conditions, ensuring reliable discharge operation.
3Reliability
If return circuit is arranged to prevent pressure decrease, then pump discharge reliability is improved, but system complexity increases
Solution Approach 1:
The return circuit is designed with multi-functionality to reduce overall system complexity. The same return pathway serves multiple purposes: preventing excessive pressure drop, enabling pressure regulation, and providing a control mechanism for maintaining reliable pump operation. This universal component performs several functions that would otherwise require separate systems.
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
Maintains stable internal pressure, prevents pump failure, and ensures consistent hydrogen supply to engines by compensating for pressure fluctuations and demand variations.
Implementation Method 1
a hydrogen pump configured to extract liquid hydrogen from the hydrogen tank
Implementation Method 2
an evaporator configured to convert the liquid hydrogen into a hydrogen gas
Implementation Method 3
an evaporator configured to convert the liquid hydrogen into a hydrogen gas
Implementation Method 4
a return circuit through which the hydrogen gas is returned to the hydrogen tank
Data Source
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AI summary
A liquid hydrogen system (10) includes a hydrogen tank (12) mounted on a vehicle and configured to store liquid hydrogen, a supply circuit (30) configured to supply a hydrogen engine (100) with a hydrogen gas which is converted from the liquid hydrogen extracted from the hydrogen tank (12), and a return circuit (60) branched from the supply circuit (30) and connected to the hydrogen tank (12), the return circuit (60) being configured to return the hydrogen gas into the hydrogen tank (12) in such a manner that the internal pressure of the hydrogen tank (12) matches or exceeds a predetermined reference pressure (Pst).