Table 4 Thermo-physical properties of hydrogen and metal hydride in model equations25,51.
From: Design optimization of a magnesium-based metal hydride hydrogen energy storage system
Parameters | Symbols | Values |
|---|---|---|
Initial temperature | \({T}_{0}\) | 573 K |
Inlet temperature of HTF | \({T}_{i,HTF}\) | 573 K |
Hydrogen exerting pressure | \({P}_{0,H2}\) | 1.8 MPa |
Molecular weight of MH | \({M}_{MH}\) | 0.1073 kg mol−1 |
Hydride specific heat | \({C}_{p,MH}\) | 1414 J kg−1 K−1 |
Density of MH | \({\rho }_{MH}\) | 3200 kg m−3 |
Density of saturated MH | \({\rho }_{ss,MH}\) | 3319.32 kg m−3 |
Reaction enthalpy | \(\Delta H\) | − 6336 J mol−1 |
Reaction entropy | \(\Delta S\) | − 120.84 J mol−1 K−1 |
Reaction rate constant | \({C}_{a}\) | 175.07 s−1 |
Activation energy | \({E}_{a}\) | 49,674 J mol−1 |
Porosity | \(\varepsilon \) | 0.5 |
Effective thermal conductivity of MH | \({\uplambda }_{MH}\) | 0.674 W m−1 K−1 |
Maximum concentration of hydrogen in the MH | \({x}_{f}\) | 1.0 |
Initial concentration of hydrogen in the MH | \({x}_{0}\) | 0.043 |
Maximum mass content of hydrogen in the metal | \(wt\) | 3.6% |
Permeability | \(K\) | 1 × 10–8 m2 |
Density of hydrogen | \({\rho }_{H2}\) | 0.32 kg m−3 |
Thermal conductivity of hydrogen | \({\uplambda }_{H2}\) | 0.167 W m−1 K−1 |
Specific heat of hydrogen | \({C}_{p,H2}\) | 14,890 J kg−1 K−1 |
Dynamic viscosity of hydrogen | \({\mu }_{H2}\) | 8.41 × 10–6 Pa s |
Molecular weight of hydrogen | \({M}_{H2}\) | 0.002 kg mol−1 |
