R32
The thermodynamic properties of refrigerant R32 are provided using the fundamental equation state described by R. Tillner-Roth and A. Yokozeki, "An International Standard Formulation for Difluoromethane (R-32) for Temperatures from the Triple Point at 136.34 K to 435 K and Pressures up to 70 MPa", J. Phys. Chem. Ref. Data, Vol. 26, No. 6, 1997.
The values of specific enthalpy and entropy are by default referred to 200 kJ/kg and 1.00 kJ/kg-K, respectively for the state of saturated liquid at 273.15 K. The reference state can be changed using the $Reference directive.
Liquid phase viscosity and conductivity data are from the generalized correlation described by:
M.J. Assael, N.K. Dalaouti, A.A. Griva, and J.H. Dymond,
"Viscosity and Thermal Conductivity of Halogenated Methane and Ethane Refrigerants",
IJR, Vol. 22, pp. 525-535, 1999.
These property correlations are applicable over the same range as the equation of state.
Gas-phase viscosity: 190 K to 350 K
Gas-phase thermal conductivity: 190 K to 350 K
Surface tension data are provided using the information in:
Mulero, A., Cachadina, I, and Parra, M.
"Recommended Correlations for the Surface Tension of Common Fluids"
J.Phys. Chem Ref. Data, Vol. 41, No.4, 2012.