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.

The PropsSI function

The general call looks like:

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

PropsSI requires the EES unit system to be set to K, Pa, J and mass. A model that uses another unit system is stopped with a message saying so, because the external function receives plain numbers and cannot tell what units they are in.

The PropsSIZ function

PropsSIZ takes the same inputs as PropsSI, and then the number of components and their mole fractions as an array, rather than encoding the composition in the fluid string. Up to three components are supported. It requires the same unit system as PropsSI.

out = PropsSIZ(output$,inputvar1$,input1,inputvar2$,input2,fluid$,N,Z[1..N])

Functions that were removed

The deprecated coolprop() and coolpropsi() functions were removed in CoolProp 8.0.1. coolprop() worked in kPa and kJ and called the CoolProp v4 API, and coolpropsi() did not work at all. A model that used coolprop() needs its pressures in Pa and its energies in J, and the call renamed to PropsSI.

Example

The following example retrieves the enthalpy of Methane at 1 bar (100000 Pa) and 15 deg C (288.15 K):

h = PropsSI('H','P',100000,'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, which is installed next to this help file, in c:\EES32\Userlib\CoolProp_EES for the 32-bit EES and in c:\EES64\Userlib64\CoolProp_EES for the 64-bit EES.

Fluid Properties

These are the property keys in common use, with the units PropsSI reads and returns them in. They are a subset: PropsSI accepts every key of the High Level API.

The two inputs have to be one of the pairs that fix the state. In either order, these are T and P, T and Q, T and D, T and H, T and S, T and U, P and Q, P and D, P and H, P and S, P and U, Q and D, Q and H, Q and S, D and H, D and S, D and U, H and S, and S and U. There is no H and U pair.