Lower and Higher Heat Values (LHV or HHV) seem to have multiple definitions based on things I can't figure out.
What I want to know is, which one is appropriate to use for calculating the thrust from a jet engine? I'm thinking of large commercial turbofan engines like on the 747 or A380.
Also, since water vapor seems to have something to do with it, what about jet engines that run on hydrogen like the experimental Tu-155? Should we use LHV or HHV to calculate thrust in those engines?