New model of phase equilibria in metal – hydrogen systems: Features and software

Metal hydride hydrogen storage and compression systems for energy storage technologies

“…For the determination of hydrogen concentrations in the studied materials at variable temperatures and H 2 pressures, we applied earlier developed model of phase equilibria in metal e hydrogen systems [56]. Within this model, the pressure e composition isotherms were constructed as pseudoconvolutions of an "ideal" isotherm built according to the model of van der Waals lattice gas (hydrogen e metal phase diagram), with two modified asymmetric pseudo Voight distribution functions (one for H desorption and another for H absorption) modelling plateau slope and hysteresis.…”

“…Table 2 presents characteristics of the studied MH materials including hydrogen absorption capacities at the room temperature (20 C) and the specified H 2 pressures, as well as temperatures which correspond to the specified plateau pressures of H 2 desorption at H concentrations which correspond to the plateau midpoint. The presented values were calculated from hydrogen absorption and desorption isotherms for the specified materials built at different temperatures using the authors' experimental PCT data further processed by the model [56]; so as the fitted model parameters allowed to build the isotherm at any selected temperature.…”

Modelling of metal hydride hydrogen compressors from thermodynamics of hydrogen – Metal interactions viewpoint: Part I. Assessment of the performance of metal hydride materials

“…1 e Determination of reversible hydrogen storage capacity/cycle productivity for the H 2 compression using LaNi 5 MH alloy. The fitted isotherms for H 2 absorption (ABS) and desorption (DES) are based on the experimental data [20] which were fitted by the PCT model [21]. The cycle productivity of 138 NL/kg is a difference between the charge capacity at T L and P L and the discharge capacity at T H and P H .…”

“…In the current study, we consider the application of our earlier developed model of phase equilibria in the metal e hydrogen systems [21] for modelling of the performances of MHHC's. The model [21] while being semi-empirical, allows to estimate temperature dependencies of the "boundary" hydrogen concentrations in the a-solid solution and b-hydride with a high accuracy. Importantly, it is able to simultaneously fit both hydrogen absorption and desorption experimental PCT data using the same set of the fitting parameters and is suitable even for the evaluation of incomplete experimental data sets.…”

“…Analysis of the application of the model [21] for the calculation of performances of hydrogen storage and compression systems utilising various MH materials has been presented in our recent publication as related to the operating temperatures and hydrogen pressures [22]. The present paper describes further details of the modelling and is focusing on evaluation of the effect of the changes in the pressures and temperatures on the productivity.…”