Gravimetric and Volumetric Hydrogen Density

The volumetric density of hydrogen in a pressure vessel increases with pressure and reaches a maximum above 1000 bar, depending on the tensile strength of the material. However, the gravimetric hydrogen density of the pressure cylinder 

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Figure 11.3. Volumetric and gravimetric hydrogen density of selected hydrides (Zuttel, 2003).

Figure 5.53 Volumetric and gravimetric hydrogen density of some selected hydrides. Mg2FeH6 shows the highest known volumetric hydrogen density of 1501 m , which is more than double that of liquid hydrogen. BaReHg has the largest H M ratio of 4.5, that is, 4.5 hydrogen...

High volumetric and gravimetric hydrogen densities due to space and weight limitations, especially in the automobile industry ... 

Table 2. Volumetric and gravimetric hydrogen densities in various media...

Figure 5.1 Volumetric and gravimetric hydrogen densities of some selected hydrides [4],...

Figure 5.7 Volumetric and gravimetric hydrogen storage density for pressurized gas. Steel (tensile strength Gv = 460MPa, density 6500 kg m ) and a hypothetical composite material (cJv— 1500 MPa, density 3000 kg m ). The circles represent pressure cylinders from Dynetek.

There are basically six methods in order to store hydrogen reversibly vith a high volumetric and gravimetric density. 

For a mobile application, the water required for thermal control and hydrogen reaction is provided by condensed water from the hydrogen fuel cell. Only a small reservoir of water is required for startup, makeup, and surge demand. Thus, the required water does not significantly affect the volumetric and gravimetric energy storage densities. 

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