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A comment on Solar-driven water splitting at 13.8% solar-to-hydrogen efficiency. Parent comment

Re:Solar-driven water splitting at 13.8% solar-to-hydrogen e... by pjc50 on Friday November 19, 2021 @07:07AM (#29276379)
If you've got H2 on a plane it's probably lighter to just feed it to the jet engine directly rather than try to replace that with a fuel cell/motor combo which will not buy you enough efficiency gain to compensate for its weight.
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Re:Solar-driven water splitting at 13.8% solar-to-hydrogen e... by viernullvier on Friday November 19, 2021 @09:14AM (#29277310)
Or maybe not. It's not the weight of the fuel cell/motor combo that is the limiting factor, but the weight of the H2 storage tanks. An H2 jet engine will probably [0] be less efficient than a fuel cell + motor, so more H2 storage is required in order to reach a comparable performance.

[0] Considering the Carnot efficiency of a jet engine at ~30%, a combination of fuel cell (~60%), motor (~95%) and propeller (~80%) will still beat it by a factor of 1.5.

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