Hi all, Which is the physical interpretation of reference specific enthalpy in the definition of the specific heat capacity? Thank you in advance

It's just the base enthalpy level for the material. i.e. h = h_ref at T=T_ref, p=p_ref.

For a constant cp gas:

h - h_ref = cp*(T-T_ref)

For a single material the value of h_ref does not really matter. If you have combustion or phase change then it matters. eg, if you have water evaporating into steam then the h_ref values have to differ at a given T/P by h_fg.

Dan.