Input energy at the heater was computed from Eqs. (21) and (22).
The experiment showed that the input energy at the heater was also
an important input in the drying medium cycle for ginger drying
in heat pump dryer, as shown in Table 2, because the heater also
played the important role of reheating the drying medium. The input
energy at the heater of air drying was lower than nitrogen because
of the lower enthalpy difference due to the lower temperature difference,
as shown in Figs. 4 and 7.