Hi :)
i toke this text from:
http://www.bmwworld.com/models/750hl.htm
Electricity generated from solar power is used to split water into
hydrogen
and oxygen. Oxygen is released into the atmosphere, while hydrogen is
liquefied and stored at a very low temperature (-253 °C).
ok, hydrogen is very light, so to store 10kg of it, we'll need a huge
tank,
but if we liquified it, we can put those 10kg in a smaller tank, then we
have to keep it cooled by special isolating... fine.
but, how do we cool it to -253 °C ?
i've been read a lot about using liquid hydrogen or nitrogen to cool
things
very low (near absolut zero), but how was the nitrogen cooled at that low
temperature?
Thanks
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