Fluid Properties

This worksheet demonstrates the functions defined in the CoolProp user function (CoolProp Mathcad Wrapper.dll).CoolProp is an open-source, cross-platform, thermophysical fluid properties database developed by Ian Bell et al. at the University of Liege, Liege, Belgium.The following URL provides full documentation of the CoolProp code: http://coolprop.sourceforge.net/EOS.html#introduction

Revision History

2013-10-04: Creation and initial release of the CoolProp Mathcad Wrapper library.S. Polak 2013-11-01: Incorporated CoolProp 4.0.0 pre-release code .S. Polak Replaced FluidsList call with FluidPropsParams. S. Polak 2013-11-21: Corrected typos and and units.S. Polak

Function Explanation & Examples

List of Fluids in the CoolProp Database (and Other Database Parameters)

Functions to parse the output of CoolProp get_global_param_string are below (hidden for clarity - double click the right-arror to expand the hidden/collapsed area)

The function FluidPropsParams("FluidsList") will output a single string representing all the fluids available in the CoolProp database.The single string-type input argument is trivial (at least one user-function argument is required by Mathcad), and does not affect the output.For clarity, the string parsing functions defined above (hidden by default) split that single string into a vector of strings, providing the scrollable list of fluids as shown below:

Click on the output vector (table) to the left to enable scrolling through the entire list

Current version of the CoolProp library

Used to retrieve the error message (if any)

Used to retrieve the warning message (if any)

Fluid Properties Not Dependent on State

The function FluidProp1 is used to extract fluid-specific parameters that are not dependent on the state. The calling struction of the function is as follows: FluidProp1(Fluid <string>, PropertyName <string>) Where "Fluid" is one of the fluid names from the FluidList table above, and "PropertyName" is one of the property name abbreviations from the table below: Tcrit - Critical temperature [K] pcrit - Critical pressure [kPa] rhocrit - Critical density [kg/m3] molemass - Molecular mass [kg/kmol] Ttriple - Triple-point temperature [K] Tmin - Minimum temperature [K] ptriple - Triple-point pressure [kPa] accentric - Accentric factor [-] GWP100 - Global Warming Potential 100 yr ODP - Ozone Depletion Potential

Example, FluidProp1

Extracts the critical density of Argon, in kg m^-3

State Dependent Fluid Properties

The function FluidProp is used to extract state-dependent fluid properties.The calling struction of the function is as follows:

FluidProp(OutputParameter <string>, Input1 Parameter <string>, Input1 Value <scalar>, Input2 Parameter <string>, Input2 Value <scalar>, Fluid <string>)

Where "Fluid" is one of the fluid names from the FluidList table above, and "OutputParameter" is one of the property name abbreviations from the table below: OutputParameterDescription [units] QQuality [-] TTemperature [K] PPressure [kPa] DDensity [kg/m3] C0Ideal-gas specific heat at constant pressure [kJ/kg] CSpecific heat at constant pressure [kJ/kg] OSpecific heat at constant volume [kJ/kg] UInternal energy [kJ/kg] HEnthalpy [kJ/kg] SEntropy [kJ/kg/K] ASpeed of sound [m/s] GGibbs function [kJ/kg] VDynamic viscosity [Pa-s] LThermal conductivity [kW/m/K] ISurface Tension [N/m] wAccentric Factor [-] The following pairs of input parameters ("Input1 Parameter" and "Input2 Parameter") are valid: Input1 ParameterInput2 Parameter TP TD PD TQ PQ HP SP SH

The defautl units system utilized by CoolProp is a modified SI units system, sometimes refered to as kSI.Default units are shown in the table of varialbes above

Examples, FluidProp

Enthalpy of Helium [kJ kg^-1] at a temperature of 300 K and a Pressure of 500 kPa

Dynamic viscosity of Water [Pa*s] at a temperature of 21 C (converted to the CoolProp temperature units, K) and a Pressure of 60 psi (converetd to the CoolProp pressure units, kPa)

Humid Air Fluid Properties

The function HAProp is used to find fluid properties of humid air.The physics behind the HAProps function is based on the analysis in ASHRAE RP-1845, which is available online: http://rp.ashrae.biz/page/ASHRAE-D-RP-1485-20091216.pdf. It employs real gas properties for both air and water, as well as the most accurate interaction parameters and enhancement factors.RP-1845 is based largely on the IAPWS-95 formulation for the properties of water.The calling struction of the function is as follows:

HAProp(OutputParameter <string>, Input1 Parameter <string>, Input1 Value <scalar>, Input2 Parameter <string>, Input2 Value <scalar>, Input3 Parameter <string>, Input3 Value <scalar>)

Where "OutputParameter" and all three Input Parameters are variables from the table below: ParameterAliasesDescription [units] TTdbDry-Bulb Temperature [K] BTwbWet-Bulb Temperature [K] DTdpDew-Point Temperature [K] PPressure [kPa] VVdaMixture volume [m3/kg dry air] RRHRelative humidity in (0,1) [-] WOmegaHumidity Ratio [kg water/kg dry air] HHdaMixture enthalpy [kJ/kg dry air] SSdaMixture entropy [kJ/kg dry air/K] CcpMixture specific heat [kJ/kg dry air/K] MViscMixture viscosity [Pa-s] KMixture thermal conductivity [kW/m/K]

Examples, HAProp

Enthalpy of humid air [kJ kg^-1] at a dry-bulb temperature of 298.15 K, a Pressure of 101.325 kPa, and relative humidity of 0.5

Temperature of saturated air (R=1.0) at the previous enthalphy value

Arrays & Plotting

Like all functions in Mathcad, the CoolProp wrapper function arguments can be array variables. If one or more function arguments are arrays, the output will also be a single or multi-dimensional array.

Examples

Plot of thermal conductivity of water at 50 psi, over the temperature range defined by T.H2O

Plot of the wet bulb temperature of humid air at various dry-bulb temperature and relative humidity ratios, at a pressure of 1 atm