Hydrogen Tank Refilling Algorithm Using Composite Heat Capacity
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Solution Overview
Problem
Current hydrogen tank refueling methods are conservative, leading to inefficiencies and increased costs due to the need for safety margins, particularly in non-communication fueling operations, where unknown parameters result in longer fill times and lower final pressures, and lack of adjustment for varying operating conditions.
Innovation Solution
The MC Method employs a new tank filling model based on total heat capacity and an advanced algorithm that improves hydrogen filling station performance by using additional thermodynamic information, allowing for faster and more accurate filling across a range of conditions, including those outside traditional SAE TIR J2601 tables, and enables lower-cost stations to meet performance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative refueling procedures are used to ensure safety, then safety margins are improved, but fill time increases and final fill pressure decreases
Solution Approach 1:
The system dynamically adjusts the refueling rate based on real-time temperature measurements from the tank. The controller continuously monitors tank temperature and modifies the dispensing rate accordingly, transitioning from static conservative rates to dynamic adaptive rates that optimize both safety and speed.
Solution Approach 2:
The system implements a feedback loop where temperature sensors continuously monitor the tank temperature during refueling, and this information is fed back to the controller which adjusts the refueling rate. This closed-loop control enables the system to respond to actual thermal conditions rather than relying on conservative predetermined rates.
2Reliability
If conservative refueling procedures are used to ensure safety, then safety margins are improved, but energy efficiency decreases
Solution Approach 1:
The system dynamically adjusts the refueling rate based on real-time temperature measurements from the tank. The controller continuously monitors tank temperature and modifies the dispensing rate accordingly, transitioning from static conservative rates to dynamic adaptive rates that optimize both safety and speed.
Solution Approach 2:
The system implements a feedback loop where temperature sensors continuously monitor the tank temperature during refueling, and this information is fed back to the controller which adjusts the refueling rate. This closed-loop control enables the system to respond to actual thermal conditions rather than relying on conservative predetermined rates.
3Reliability
If pre-cooling temperature is increased to maintain safety specifications, then safety is improved, but station cost increases
Solution Approach 1:
The system uses the tank itself as the cooling mechanism by leveraging the endothermic expansion of hydrogen during dispensing. The expanding cold hydrogen naturally cools the tank during the refueling process, eliminating or reducing the need for external pre-cooling infrastructure and associated costs.
Solution Approach 2:
The system converts the cold effect of expanding hydrogen (which was previously considered a potential hazard requiring mitigation) into a beneficial cooling mechanism. The endothermic expansion that naturally occurs during dispensing is harnessed to cool the tank, turning a potential problem into a solution that reduces pre-cooling requirements.
4Use of energy by moving object
If pre-cooling temperature is decreased to reduce energy use, then energy efficiency is improved, but customer satisfaction decreases due to longer wait times
Solution Approach 1:
The system dynamically adjusts the refueling rate based on real-time temperature measurements from the tank. The controller continuously monitors tank temperature and modifies the dispensing rate accordingly, transitioning from static conservative rates to dynamic adaptive rates that optimize both safety and speed.
Solution Approach 2:
The system implements a feedback loop where temperature sensors continuously monitor the tank temperature during refueling, and this information is fed back to the controller which adjusts the refueling rate. This closed-loop control enables the system to respond to actual thermal conditions rather than relying on conservative predetermined rates.
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 MC Method enhances fill speed and quality, allows for more efficient energy use, and maintains safety margins, enabling hydrogen filling stations to operate effectively under various conditions without the need for extensive pre-cooling or communication protocols.
Implementation Method 1
a hydrogen station or dispenser continuously calculates the mass average enthalpy of the hydrogen fill, with the mass average enthalpy estimated prior to the fill being conducted
Implementation Method 2
the refueling of compressed hydrogen tanks are to be conducted in a manner that prevents the tank from overheating (temperatures exceeding 85° C.) during refueling
Data Source
AI summary
Disclosed is an improved analytical method that can be utilized by hydrogen filling stations for directly and accurately calculating the end-of-fill temperature in a hydrogen tank that, in turn, allows for improvements in the fill quantity while tending to reduce refueling time. The calculations involve calculation of a composite heat capacity value, MC, from a set of thermodynamic parameters drawn from both the tank system receiving the gas and the station supplying the gas. These thermodynamic parameters are utilized in a series of simple analytical equations to define a multi-step process by which target fill times, final temperatures and final pressures can be determined. The parameters can be communicated to the station directly from the vehicle or retrieved from a database accessible by the station. Because the method is based on direct measurements of actual thermodynamic conditions and quantified thermodynamic behavior, significantly improved tank filling results can be achieved.