Critical Point Water Steam

Overview

Engineering reference data for Critical Point Water Steam in thermodynamics.

Key Formulas

First Law

$\Delta U = Q - W$

Energy is conserved — heat added minus work done.

Ideal Gas Law

$PV = nRT$

Relates pressure, volume, and temperature of an ideal gas.

Heat Transfer

$Q = mc\Delta T$

Sensible heat transfer.

Carnot Efficiency

$\eta = 1 - T_C/T_H$

Maximum efficiency between two temperatures.

Variables

Critical Point Properties

The critical point of water represents a state where the liquid and gas phases become indistinguishable, and no phase change occurs with pressure increase or heat addition.

• Pressure: 217.75 atm = 220.64 bar = 22.064 MPa = 3200.1 psi
• Temperature: 647.096 K = 373.946 °C = 705.103 °F
• Density: 0.322 g/cm³ = 0.6248 slug/ft³ = 20.102 lbm/ft³

Triple Point Properties

The triple point of water is the condition where solid (ice), liquid (water), and gas (steam) coexist in thermodynamic equilibrium.

• Pressure: 0.00604 atm = 6.12 mbar = 611.657 Pa = 0.08871 psi
• Temperature: 273.16 K = 0.01 °C = 32.02 °F
• Liquid Density: 0.99979 g/cm³ = 1.93991 slug/ft³ = 62.4148 lbm/ft³

Supercritical vs Superheated Steam

• Supercritical steam exists above the critical point, where water transitions directly to a supercritical fluid without boiling, exhibiting combined liquid and gas properties.
• Superheated steam is formed when saturated steam (at subcritical pressures) is heated above its saturation temperature, remaining in the gas phase with distinct phase boundaries.

References

• Original Source