Enthalpy of vaporisation h_fg at a given pressure - the heat required to turn 1 kg of saturated water into 1 kg of saturated steam.
Formula
$$ h_{fg} = h_g - h_f \approx 2500 - 2.42 \cdot T_\text{sat} \text{ (kJ/kg)} $$Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $h_f$ | Saturated liquid enthalpy | kJ/kg | IAPWS-IF97 |
| $h_g$ | Saturated vapour enthalpy | kJ/kg | IAPWS-IF97 |
| $h_{fg}$ | Latent heat of vaporisation | kJ/kg | h_g − h_f |
Sources
- IAPWS IF97.
- ASME Steam Tables.