Simulation And Optimization For Cryo-adsorrptive Hydrogen Storage System

As a renewable energy source, the hydrogen energy receives widespread concerns. Many affords have been devoted to the commercial application of hydrogen energy, however, the hydrogen storage technology remains one of the primary bottlenecks. This paper establishes a lumped parameter model for charge-discharge cycle of cryo-adsorptive hydrogen storage system which implemented on Matlab/Simulink. This model is developed based on the mass and energy conservation equations of system and adsorption equation. A modified Dubinin-Astakhov (D-A) equation is used to describe the hydrogen storage process in the hydrogen storage system. This model can well predict the variations of parameters during the whole cryo-adsorptive hydrogen storage process, such as lumped pressure, average temperature and the mass balance.This work has some new features.(1) Lumped parameter simulation is made for charge-discharge cycle of adsorptive hydrogen storage system under cryonic condition by Matlab/Simulink.(2) The change of interface between liquid and gaseous nitrogen is considered in the lumped parameter model to improve simulation accuracy.(3) Thermal average temperatures are introduced to be compared with the temperature distributions obtained from multidimensional models.(4) The variational isosteric heat of adsorption based on Dubinin-Astakhov isotherm of adsorption is used for adsorption model.Firstly, dynamic simulations are carried out for Test No.42, Test No.44and Test No.46. The simulation result, compared with experimental data and validated by experimentation, shows that the lumped parameter model of cryo-adsorptive hydrogen storage system on activated carbon (AC) is quite accurate and creditable. On this basis, the effect of the charge flow rate on the performance of the hydrogen storage system is systematically analyzed.Furthermore, the charging and discharging processes of an adsorptive hydrogen storage system on metal-organic frameworks (MOF) are respectively simulated in room temperature and liquid nitrogen cooling condition. The simulations reveal that the metal-organic frameworks has shown good storage capability at low temperature. The average temperature calculated by models based on Comsol MultyphysicsTM software will be introduced as reference average temperature since the absence of experimental average temperature data. There are good agreements among these three simulation results. And compare with activated carbon, the densities of the adsorbents have significant effect on the storage capabilityFinally, we combine the applications of croy-adsorptive hydrogen storage system with hydrogen-powered car. Mainly due to the fact that the hydrogen storage need arranged in the trunk of the car, the150-liter volume hydrogen storage was considered. In here, rely on the lumped parameter model, it’s essential to predict the hydrogen storage capability. The predicted results show that hydrogen-powered car could complete the ninety percent of the hydrogen storage amount in83minutes under100atmospheres. The automobile with the hydrogen storage on metal-organic frameworks can travel as far as440km on a single charge, while the activated carbon is doubled. Moreover, the automobile adsorptive hydrogen storage system also need to be optimized for maximum performance, the result shows that enlarge the charge flow rate could minimize the charging time, make people more accustomed to fueling quickly in daily life.