Formula & Engineering Notes
Energy rate of a flowing stream:
Enthalpy h is interpolated at (P, T) from the steam tables; flow is converted to kg/s. The same rate is reported in kW, MJ/hr and kcal/hr.
All steam properties are interpolated from the shared IAPWS-IF97 steam-table datasets — see the full steam tables and the Steam Property Calculator.
This one trips up juniors because the number looks huge — and it is, because enthalpy is referenced to a near-absolute zero. The headline figure isn't what you bill or burn; it's the energy carried by the stream. The useful work always comes from a difference in h between two points (inlet vs outlet of a heater, turbine, condenser).
Treat this calculator as the building block: get the energy rate at each state point, then subtract to get duty. That's exactly how the boiler-duty and turbine-power tools next door work.