The Critical Role of Simulation in Developing Hydrogen Refuelling line Components for the RHeaDHy Project

Hydrogen is an alternative fuel for heavy-duty trucks, capable of reducing greenhouse gas emissions and increase energy efficiency. The RHeaDHy project aims to build a high-flow hydrogen refuelling stations designed to serve heavy-duty vehicles such as buses and trucks. Simulation has become an indispensable tool in the development of advanced refuelling line components, particularly within ambitious projects like RHeaDHy. This initiative aims to innovate refuelling line components and stations capable of implementing and testing new H2 high flow refuelling protocols for heavy-duty vehicles, ensuring their readiness for market introduction.

What is a simulation?

A simulation is a computational technique that replicates the operations of various real-world processes and systems over time. Utilizing mathematical models and algorithms, simulations enable the study and analysis of complex systems by creating a virtual representation that can be manipulated and observed under different scenarios. This method provides valuable insights into the behaviour and performance of the system, allowing for predictions, optimizations, and testing without the need for physical prototypes or experiments.

Why using simulation?

The strategic use of simulations offers a multitude of benefits, from cost reduction to time efficiency. During the initial phase of component development, simulations had been used for virtual testing, drastically reducing the need for multiple physical prototypes. This not only saves on material costs but also significantly shortens development timelines. For example, in the development of the heat exchanger made by Alfa Laval, simulations enabled us to analyse mechanical fatigue under more than 250 000 complete refuelling cycles—an endeavour that would have been impractical to achieve experimentally within the first 18-month development period.

Without simulations, manufacturers face increased expenses and prolonged timelines due to the necessity of testing multiple physical prototypes. Additionally, the optimization of designs becomes more challenging, possibly resulting in less efficient and less reliable products. Simulations within the RHeaDHy project have allowed us to specify operating points that minimize the total pressure drop across the refuelling line, a task that would have required extensive experimental testing and iterative adjustments in the absence of simulations.

Simulations based on HyFill

The accuracy and reliability of simulations hinge on the physical models used. These models, built on established laws and equations, must undergo rigorous experimental validation to ensure their predictive reliability. Within the RHeaDHy project, we utilize the HyFill pseudo-1D model developed by Engie Lab CRIGEN on Matlab/Simulink to contribute to the reflection on hydrogen mobility and more particularly on hydrogen refuelling stations. HyFill allows simulating the fast filling and emptying of compressed hydrogen tanks in order to predict the final thermodynamic state reached by the hydrogen. Hyfill also allows simulating the evolution of the whole HRS during a refuelling. This model had been validated through extensive experimental comparison and was one of the models used to develop specific protocols for the European PRHYDE project.

Challenges in simulation

One of the primary challenges in the simulation is the collection of a vast array of input parameters, which can exceed more than a hundred. These parameters range from the thermo-physical characteristics of refuelling line components to the design specifications of line equipment such as compressor and chiller capacities. The precision of simulation outcomes, whether in terms of filling times, the final thermodynamic state of refuelled vehicle tanks, or station power consumption, is contingent upon the accuracy of these inputs. Despite the extensive data requirements, the collaborative nature of our projects and the comprehensive database of HRS component characteristics we have amassed enable us to make reliable assumptions and ensure the consistency of our simulation results.

Conclusion

Simulation is a crucial asset in the development and production of refuelling line components, providing unparalleled advantages in cost efficiency, time savings, performance optimization, and safety assurance. However, leveraging these benefits necessitates a thorough understanding of the station’s thermodynamic models, precise input data, and advanced software tools such as Matlab/Simulink and AFT Arrow. Recognizing and addressing the limitations and uncertainties inherent in simulation is equally essential to harnessing its full potential.

Authors: Thomas Guewouo (ENGIE – lab CRIGEN), and Jean Herisson (Benkei)