Steam Properties Calculator
Calculate steam and water properties at any temperature or pressure.
Find saturation temperature, enthalpy, entropy, specific volume, and latent heat of vaporization using steam tables.
Why Steam Properties Matter Water and steam are used in boilers, turbines, heat exchangers, HVAC systems, and power plants worldwide. Steam properties depend on both temperature and pressure — and the phase (liquid, saturated mixture, or superheated vapor). Engineers rely on steam tables (published since 1900s) or equations of state to look up these properties.
Phases of Water Subcooled liquid: water below saturation temperature at given pressure. Saturated mixture: water and steam coexist at saturation temperature/pressure. Superheated steam: steam above saturation temperature — dry, no liquid droplets. The saturation curve defines the boundary between these phases.
Key Properties Saturation temperature T_sat: temperature at which water boils at a given pressure. At 1 atm (101.325 kPa): T_sat = 100°C. At 10 bar: T_sat ≈ 179.9°C. Enthalpy of vaporization (latent heat) hfg: energy to convert 1 kg of saturated liquid to saturated vapor. At 100°C: hfg ≈ 2257 kJ/kg. At 200°C: hfg ≈ 1940 kJ/kg. Specific enthalpy h: total heat content per kg (kJ/kg). Specific entropy s: irreversibility measure, used in turbine efficiency calculations.
Antoine Equation (saturation pressure) Approximate saturation pressure: log₁₀(P) = A − B/(C + T) For water (T in °C, P in kPa): A = 8.07131, B = 1730.63, C = 233.426 (for 1–100°C range). For higher temperatures, the IAPWS-IF97 formulation is the international standard.
Rankine Cycle (Steam Power Plants)
- Feed water pump: liquid water pressurized (small work input)
- Boiler: heat added at constant pressure → superheated steam
- Turbine: steam expands, producing shaft work (turbine output)
- Condenser: steam condenses back to liquid (heat rejection) Thermal efficiency: η = W_net / Q_in = 1 − Q_out/Q_in Modern coal plants: 35–45% efficient. Combined cycle gas plants: 55–60%.
Critical Point of Water At the critical point: T_c = 374.14°C, P_c = 220.64 bar, ρ_c = 322 kg/m³. Above the critical point, there is no distinct liquid–vapor transition. Supercritical steam plants (P > 220 bar) have higher efficiency but require special materials.
HVAC and Process Engineering Steam at 5–15 psig (135–125 kPa gauge) is typical for building heating. High-pressure steam (150–600 psig) is used for industrial process heat. Flash steam: when high-pressure condensate is released to lower pressure, some re-vaporizes. Steam traps prevent live steam from bypassing heat exchangers.