Thermodynamical analysis of a hydrogen fueling station via dynamic simulation

Abstract

This article describes the thermodynamical analysis of a hydrogen (H2) fueling station (HFS) with cryopump technology. A dynamic, object-oriented computer model of the HFS is developed in Matlab-Simulink. This model calculates, amongst other thermodynamic properties, the temporal and spatial variation of the H2 temperature and the component temperatures within the HFS. The validation of the computer model with data from a series of measurements at a testing facility confirms a good accuracy of the model. The most important model object is the high pressure pipe through which the H2 flows. The pipe is modeled and validated in different configurations. The thick-walled pipe material is discretized in radial and axial direction. In comparison to measurements the simulations show acceptable accuracy with an radial discretization length of s<0.0026m. In axial direction a discretization length of l<1.18m is found to deliver acceptable accuracy of the simulations compared to measurements. Based on the simulation results a new method of controlling the H2 temperature by mixing two H2 mass flows with different temperatures is assessed as practicable. The electrical power requirement of the electric heat exchanger in this HFS design is determined. Depending on the load cases it varies between 0.13kWhel/(kgH2) and 0.40kWhel/(kgH2).