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This article describes the thermodynamical analysis of a hydrogen ( H 2 ) 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 H 2 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 H 2 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 < 0.0026 m. In axial direction a discretization length of l < 1.18 m is found to deliver acceptable accuracy of the simulations compared to measurements. Based on the simulation results a new method of controlling the H 2 temperature by mixing two H 2 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 0.13 kWh el / (kg H 2 ) and 0.40 kWh el / (kg H 2 ). [ABSTRACT FROM AUTHOR]

Abstract: The sulfur–iodine thermochemical water-splitting cycle (S–I cycle) is one of the most promising technologies for mass H2 production. The S–I cycle is generally divided into three sections, one of which involves a H2SO4 concentration and decomposition. In the sulfuric acid processing section (Section 2), H2SO4 is decomposed into H2O and SO3, and then the produced SO3 is further decomposed into SO2 and O2, which takes place in a H2SO4 decomposer and a SO3 decomposer, respectively. The SO3 decomposition requires heat of a high temperature and this suggests a heat-exchanger type reactor. To understand the temperature profiles and chemical reactions through a SO3 decomposer, a dynamic model was developed by considering the heat and material balances in partial differential forms. A model was used to size the decomposer to a proposed design basis and it was also applied to simulate the responses corresponding to the changes of the operation conditions such as increased or decreased flow rates. [Copyright &y& Elsevier]