Difference in calculated values between CoolProp and Refprop

[enerb...@gmail.com]

Hello,

I'm new to CoolProp. 

I'm trying to calcolate the boiling point of some refrigerants (e.g. R134a, R410A) with the formula:

=PropsSI("T";"P";1000000;"Q";0;"HEOS::R134a)-273,15

Comparing the results with RefProp there are some differencies:

CoolProp: 

42,96935029 °C

RefProp: 

43.1....°C

Maybe I'm missing some parameter, or the sintax of the PropSI function is wrong.

Can anybody give me some hint? What are your experiencer in CoolProp/RefProp comparision?

Thanks

Mg

[Ian Bell]

Hi!

Did you do exactly the same calculation in both libraries?  For pure fluids like R134a, so long as the equation of state is the same (it should be in this case), the results should be much, much closer.  For instance there are some plots you can look at in the docs to compare with REFPROP: http://www.coolprop.org/fluid_properties/fluids/R134a.html#fluid-r134a.  They look pretty much fine.

You should try to do:

PropsSI("T";"P";1e6;"Q";0;"HEOS::R134a")-273,15

PropsSI("T";"P";1e6;"Q";0;"REFPROP::R134a")-273,15

and see what values you get for both.

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[enerb...@gmail.com]

Thank You for the answer.

I'cant make the check right now - unfortunately I have not the RefProps DLLs installed on this PC - I made a comparision using a custom software, (based on RefProps) and an simplier app.

Is there some configuration parameter that can effect the results, maybe the Reference States? It is possible to set the reference state also by high level interface (Excel)? There is no  set_reference_stateSn example in the TestExcel file.


Can You maybe provide me the outputs of the functions:

   PropsSI("T";"P";1e6;"Q";0;"HEOS::R134a")-273,15

   PropsSI("T";"P";1e6;"Q";0;"REFPROP::R134a")-273,15

from Your system, so I can compare with my calculations?

Thank You for your help.

Mg

[Matthis Thorade]

Hi,
the reference state will only have an effect on enthalpy, entropy, internal energy, Gibbs energy, Helmholtz energy.
It does NOT have any effect on pressure, temperature, density, heat capacity, compressibility, speed of sound, ...
So that is probably not be the source of the differences in your case.
https://github.com/CoolProp/CoolProp/blob/master/FAQ.md
http://www.coolprop.org/coolprop/HighLevelAPI.html#reference-states

[enerb...@gmail.com]

Il giorno martedì 20 febbraio 2018 20:51:53 UTC+1, enerb...@gmail.com ha scritto:

[enerb...@gmail.com]

Thank You for the answers,

it seems that the reason for the different values was a trivial typing error in the Excel formula.

Sorry for the inconvenience.

Mg

[Ian Bell]

Aha, good to hear!  Thanks for asking your question!

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