Charging and Discharging of Hydrogen Sorption Storage Tank

The application of hydrogen in order to store energy and as a vehicle fuel requires efficient and effective storage technologies. An alternative solution to cryogenic and high pressure tanks is the use of porous material and physisorption (carbons, metal organic frameworks) or chemisorption (hydrides) in the tank. Due to the heat of sorption the temperature and its distribution in the tank might vary significantly during charging and discharging, affecting the storage capacity. The flow of the hydrogen in the tank is described by the equation of mass conservation, the Navier-Stokes equations and the equation of energy conservation as implemented in a CFD code. In the conservation equation additional terms are implemented in order to account for the amount of hydrogen involved in the sorption and the corresponding heat of sorption. These result from the mass and energy balance for the hydrogen in a finite volume whereat the equilibrium is described by an appropriate sorption isotherm. The use of data driven models is often computationally more advantageous then physical models. Based on the physical adsorption model a data driven model is derived using different machine learning techniques. This model is implemented as source terms in the governing equations, leading to a computationally more advantageous formulation. Thus the distribution of temperature and concentration during charging and discharging of the tanks is computed and limiting phenomena are identified.