Reply to post: Re: ero emissions?

Brits rattle tin for 'revolutionary' hydrogen-powered car


Re: ero emissions?

Second, scuba tanks are routinely pressurised at similar pressure and have a life of hunderds of thousands of cycles.

No, not really.

Most scuba cylinders in the UK have a working pressure of 232bar; these are pressurised to a test pressure of 348bar once every 5 years. A 30-year-old cylinder has only experienced this sort of pressure a handful of times...

There are a range of 300-bar cylinders in use; these have their own problems (not least that the gases are very much non-ideal at those pressures, so you don't get nearly as much as you thought you might[1]), Weight does become an issue...

And all this is before we get to the problems of hydrogen - others have mentioned embrittlement, I'll mention leakage...


[1] I've just done a quick calculation using an online Van der Waal's calculator. I used a 20l cylinder blown to 350bar at 300K, which gave me 204mol H2. That much gas at 1bar gives 5100l, rather than the 7000l one might naively expect...

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