# General Information

The CoolProp library is a standard interface between EES and the CoolProp library. CoolProp is a fluid property database written by Ian Bell and co-authors and is open-source and free. In addition, REFPROP can be called through CoolProp if is installed on the computer

More information on CoolProp can be obtained at www.coolprop.org. Furthermore, information on the EES wrapper can be found at EES.

#### CoolProp v5+ Support

The wrapper for EES is now essentially 100% in line with the other wrappers for Python, Excel, etc. Users should use the PropsSI function. This function always takes in and returns base SI units (Pa, J, kg, mol, etc.). The documentation for the PropsSI function is exactly in line with that for the High Level API. No other functions from the high-level API are exposed through the EES interface.

#### CoolProp v4 backwards compatibility

For backwards compatibility, the coolprop() function has been retained in EES. The coolprop() function has been officially deprecated and will be removed in a future release. The PropsSI function is the only function that will be supported in the future.

The general call looks like:

out = PropsSI(output$,inputvar1$,input1,inputvar2$,input2,fluid$)

A modified SI system of units is used in CoolProp. The units employed are shown below.

### Example

The following example retrieves the enthalpy of “Methane”. The thermodynamic state is given by two variables : p and T, that are set to 1 bar (100 kPa) and 15 °C (288.15 K) respectively:

h = PropsSI('H',’P',100,’T’,288.15,’Methane’)

A complete list of fluids that can be used in CoolProp for EES can be found at Fluid Properties

The EES function PropsSI() uses the same fluids and inputs as the function PropsSI from the high level interface. The documentation there is generally more up-to-date.

Also refer to the example file at c:\EES32\Userlib\CoolProp_EES\CoolProp_EES_Sample.ees

### Fluid Properties

Thermophysical property | Symbol | Units | Input/Output
Pressure (absolute) | P | kPa | Both
Temperature | T | K | Both
Density | D | kg/m3 | Both
Specific Enthalpy | H | kJ/kg | Both
Specific Entropy | S | kJ/kg/K | Both
Quality | Q | kg/kg | Both
Specific Internal Energy | U | kJ/kg | Output only
Specific Gibbs Function | G | kJ/kg | Output only
Specific Heat at Constant Volume | O | kJ/kg/K | Output only
Specific Heat at Constant Pressure | C | kJ/kg/K | Output only
Speed of Sound | A | m/s | Output only
Surface Tension | I | N/m | Output only
Viscosity | V | Pa·s | Output only
Thermal Conductivity | L | kW/m/K | Output only
Critical Temperature | Tcrit | K | Output only
Critical Pressure | pcrit | kPa | Output only
Minimum Temperature | Tmin | K | Output only

The following combinations of inputs are valid (in either order):

- T,P
- T,Q
- T,D
- P,H
- P,S
- P,Q

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