**R22**

Fluid R22 implements the thermodynamic properties of refrigerant R22 using the fundamental equation state described by Wagner, W., Marx, V., Prob, A., "A New Equation of State for Chlorodifluoromethane covering the entire fluid region from 116 K to 550 K at pressures up to 200 MPa, Int. J. Refrig, 16:373, 1993.

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.

__Transport Properties:__

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: 250 K to 440 K

Gas-phase thermal conductivity: 230 K to 645 K

__The surface tension function has been fit to data provided by__

Liley and Desai,

"Thermophysical Properties of Refrigerants",

ASHRAE, 1993, ISBN 1-1883413-10-9. It is valid for temperatures between -150 C to 90 C.

A computationally more efficient but potentially less accurate formulation for ammonia properties is available with fluid name R22_mh.