IAPWS-IF97 Formulas Used

This calculator implements the International Association for the Properties of Water and Steam Industrial Formulation 1997 (IAPWS-IF97).

Region 1 (Liquid Phase)

Fundamental equation: γ(π,τ) where π = p/p*, τ = T*/T

p* = 16.53 MPa, T* = 1386 K

Region 2 (Vapor Phase)

Fundamental equation: γ°(π,τ) + γʳ(π,τ)

p* = 1 MPa, T* = 540 K

Region 3 (Critical Region)

Fundamental equation: φ(δ,τ) where δ = ρ/ρ*, τ = T*/T

ρ* = 322 kg/m³, T* = 647.096 K

Region 4 (Saturation Curve)

Saturation-pressure equation: pₛ(T)

Saturation-temperature equation: Tₛ(p)

About Steam Tables

Steam tables are essential tools in thermodynamics and engineering for determining the properties of water and steam under various conditions.

Key Properties

• Specific Volume (v): Volume per unit mass (m³/kg)
• Internal Energy (u): Energy due to molecular motion (kJ/kg)
• Enthalpy (h): u + pv (kJ/kg)
• Entropy (s): Measure of energy unavailability (kJ/kg·K)

Common States

• Saturated Liquid (f): Liquid at boiling point
• Saturated Vapor (g): Vapor at condensation point
• Superheated Vapor: Vapor above saturation temperature
• Compressed Liquid: Liquid below saturation temperature but under pressure