Active Venting Control for Liquid Hydrogen Tanks
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Solution Overview
Problem
Hydrogen fuel tanks for vehicles face challenges in minimizing fuel loss and maintaining operational pressure due to ambient heat causing pressure increases, which necessitates venting but results in hydrogen loss.
Innovation Solution
An active venting control system is implemented, comprising sensors to measure temperature, pressure, and hydrogen mass, and a controller that adjusts an active venting valve to manage the fill level and pressure within the tank, minimizing hydrogen loss while maintaining safe pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the tank is vented to avoid over-pressurization caused by ambient heat infiltration, then the pressure is controlled within safe limits, but a portion of gaseous hydrogen is released resulting in fuel loss
Solution Approach 1:
The system performs preliminary action by calculating the projected fill level before venting occurs. The controller uses sensor data (temperature, pressure, mass) to predict future fill levels and adjusts venting timing accordingly, allowing the tank to retain more fuel while still preventing over-pressurization. This proactive approach replaces reactive venting with predictive control.
Solution Approach 2:
The system implements feedback control by continuously monitoring temperature, pressure, and hydrogen mass through sensors, then using this data to calculate effective fill level and adjust venting decisions dynamically. The controller compares calculated fill levels against thresholds and modulates the vent valve accordingly, creating a closed-loop system that minimizes fuel loss while maintaining safe pressure levels.
2Quantity of substance
If the tank is filled to higher levels to maximize fuel capacity, then the energy storage increases, but the risk of over-pressurization increases due to heat infiltration
Solution Approach 1:
The system calculates projected fill levels in advance using thermal models and sensor data, allowing operators to fill tanks to higher levels confidently. By predicting how the fill level will evolve under ambient heat conditions, the system enables higher initial fill levels while maintaining safety margins, thus increasing fuel capacity without compromising reliability.
Solution Approach 2:
The feedback mechanism continuously monitors actual temperature, pressure, and mass against predicted values, allowing the system to adapt to real-world conditions. This enables the tank to be filled to higher levels by dynamically adjusting venting based on actual thermal infiltration rates, thereby maximizing capacity while maintaining pressure safety through real-time validation.
3Loss of substance
If conventional passive venting systems are used to maintain pressure, then the system is simple and reliable, but fuel loss increases significantly
Solution Approach 1:
The system replaces purely mechanical passive venting with an electronically controlled active venting system. The controller uses sensor data and calculations to electronically modulate the vent valve, substituting intelligent control logic for simple mechanical pressure-activated venting. This increases complexity but dramatically reduces fuel loss through precise control.
Solution Approach 2:
The system changes the control parameter from simple pressure threshold (passive) to calculated effective fill level (active). By using multiple parameters (temperature, pressure, mass) to compute fill level rather than relying solely on pressure, the system achieves more precise control over venting decisions, reducing fuel loss despite increased system complexity.
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 active venting control system allows for a higher initial fill level and increased retention of hydrogen over time, reducing fuel loss by approximately 38.6% compared to conventional passive venting systems, while ensuring safe operational pressures.
Implementation Method 1
a passive pressure relief valve operatively coupled to the hydrogen fuel tank and configured to automatically move to an open position when the tank pressure exceeds a relief pressure threshold
Implementation Method 2
an active venting valve movable between an open position and a closed position operatively coupled to the hydrogen fuel tank for communication with the gaseous hydrogen
Implementation Method 3
A plurality of sensors operatively coupled to the hydrogen fuel tank and configured to measure a liquid temperature, a vapor temperature, a tank pressure, and a hydrogen mass
Data Source
AI summary
The present disclosure provides active venting control systems for use with liquid hydrogen tanks. The active venting control system allows a greater mass of hydrogen to be safely stored for a greater period of time. The systems is configured to actively monitor, control, and vent hydrogen based on a combination of pressure and fill level within the tank. When the tank reaches a predetermined fill level, the active venting control system is configured to vent the tank for a predetermined period of time. The active venting control system is configured to repeat the process during a transit and storage time, allowing the tank to be filled with a higher initial fill level and hold a greater mass of hydrogen compared to passive pressure relief systems.