It same issue as
with some test results.
Hydrogen freeze to liquid after less than one (about 3/4) cycle.
Hydrogen freeze after about half cycle.
Also, in begin state (fill pipe, power shut-off) hydrogen in pipes (both radiant and common) almost no change temperature and oscillate around start temperature (cool down to 0.1 deg then restore, in radiant pipes with very slow cooling).
No test for liquid pipes.
Create radiator with radiant pipe.