Thermophysical properties of seawater

Version: 8 July 2016. Please update from earlier versions.

Description

This page provides tables and a library of computational routines for the thermophysical properties of seawater. The properties given by these codes are those needed for design of thermal and membrane desalination processes. They are given as functions of temperature, pressure, and salinity.

The temperature and salinity ranges are 0 - 120 °C and 0 - 120 g/kg respectively. Some functions are valid only near atmospheric pressures while others are valid for a pressure range of 0 - 12 MPa. For thermodynamic functions, the pressure dependence across 0 - 12 MPa has been incorporated. For select functions such as transport and colligative properties, the temperature and salinity also implicitly define the pressure as:

Pressure definition equation

where P0 is taken as atmospheric pressure (0.101325 MPa) up to 100 °C and as the vapor pressure of seawater for higher temperatures.

Implementation and Fair Usage

The seawater properties library routines are available in MATLAB, EES, and Excel VBA. They are a self-contained library and are extremely easy to use. They will run on all computers that support MATLAB, EES, or VBA. This software is provided "as is" without warranty of any kind. See the file sw_copy.m or sw_copy.txt for conditions of use and license.

While the seawater properties library routines are freely distributed, it is requested that users of this library please cite the following two journal articles which comprehensively present how correlations in the library were developed, the original data sources, the validity ranges, and the uncertainty in each property function.

  1. K.G. Nayar, M.H. Sharqawy, L.D. Banchik, and J.H. Lienhard V, "Thermophysical properties of seawater: A review and new correlations that include pressure dependence," Desalination, Vol. 390, pp.1-24, 2016. doi:10.1016/j.desal.2016.02.024
  2. Mostafa H. Sharqawy, John H. Lienhard V, and Syed M. Zubair, "Thermophysical properties of seawater: A review of existing correlations and data," Desalination and Water Treatment, Vol. 16, pp.354-380, April 2010. (PDF file which includes corrections through January 2016.)

Bibtex formatted references.

Downloads

Installation

For MATLAB:

For EES:

For Excel VBA:

Property Functions

Property (unit) Temperature, t (°C)Salinity, S (g/kg) Pressure, P (MPa) Function name
Boiling point elevation (K) 0 - 2000 - 120P0SW_BPE(T, S)
Chemical potential of salts in seawater (J/kg)10 - 800.1 - 1200 - 12ChemPot_S(T, S, P)
Chemical potential of water in seawater (J/kg) 10 - 80 0 - 120 0 - 12 ChemPot_W(T, S, P)
Density (kg/m3) 0 - 180 0 - 150 0 - 12 SW_Density(T, S, P)
Dynamic viscosity (kg/m-s) 0 - 180 0 - 150 P0 SW_Viscosity(T, S)
Isobaric expansivity of seawater (1/K) 10 - 180 0 - 150 0 - 12 SW_IsobExp(T, S, P)
Isothermal compressibility of seawater (1/MPa) 10 - 180 0 - 160 0 - 12 SW_IsothComp(T, S, P)
Kinematic viscosity (m2/s) 0 - 180 0 - 150 P0 SW_Kviscosity(T, S)
Latent heat of vaporization (J/kg) 0 - 200 0 - 240 P0 SW_LatentHeat(T, S)
Osmotic coefficient 0 - 200 0 - 120 P0 SW_OsmCoeff(T, S)
Osmotic pressure (MPa) 0 - 200 0 - 120 SW_OsmPress(T, S)
Prandtl number 0 - 180 0 - 150 P0 SW_Prandtl(T, S)
Specific enthalpy (J/kg) 10 - 120 0 - 120 0 - 12 SW_Enthalpy(T, S, P)
Specific entropy (J/kg-K) 10 - 120 0 - 120 0 - 12 SW_Entropy(T, S, P)
Specific flow exergy (J/kg) 10 - 80 0 - 120 0 - 12 SW_Exergy(T, S, P, Tds, Sds, Pds)*
Specific Gibbs energy (J/kg) 10 - 120 0 - 120 0 - 12 SW_Gibbs(T, S, P)
Specific heat capacity (J/kg-K) 0 - 180 0 - 180 0 - 12 SW_SpcHeat(T, S, P)
Specific internal energy (J/kg) 10 - 120 0 - 120 0 - 12 SW_IntEnergy(T, S, P)
Specific volume (m3/kg) 0 - 180 0 - 150 0 - 12 SW_Volume(T, S, P)
Surface tension (mN/m) 0 - 100 0 - 131 P0 SW_SurfaceTension(T, S)
Thermal conductivity (W/m-K) 0 - 180 0 - 160 P0 SW_Conductivity(T, S)
Thermal conductivity (pressure dep.) (W/m-K) 10 - 90 0 - 120 0 - 12 SW_ConductivityP(T, S, P)
Thermal diffusivity (m2/s) 0 - 180 0 - 150 P0 SW_Diffusivity(T, S)
Vapor pressure (Pa) 0 - 180 0 - 160 SW_Psat(T, S)

* Tds, Sds, and Pds are the dead state temperature, salinity, and pressure. The default values are Tds = 25 °C, Sds = 35 g/kg, and Pds = 0.101325 MPa

Seawater Surface Tension

The surface tension correlation used in this package is based on Nayar et al. (2014). They published reference data for the surface tension of seawater over the salinity range of 20 - 131 g/kg and a temperature range of 1 - 92 degC at atmospheric pressure. The uncertainty of the measurements varied from 0.18 to 0.37 mN/m with the average uncertainty being 0.22 mN/m. This data was correlated with an average absolute percentage deviation between measurements and the correlation of 0.19% and a maximum deviation of 0.60%.