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Ortho-H2 enthalpy datum #662

Open DaveCryo opened 2 months ago

DaveCryo commented 2 months ago

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Description

My problem in a nutshell, a) REFPROP enthalpy and entropy datum values for Para-H2 are zero at NBP. b) I would like to be able to change the enthalpy datum value of Ortho-H2 from 444.92 J/g to 703 J/g (rounded value). With this change the enthalpies of O-H2 and P-H2 would differ by the exothermic heat of conversion.

Is this possible? If so please let me know how. (I am not a VB programmer).

If the enthalpy datum for O-H2 is adjusted as suggested, it may be advisable for its entropy datum to be changed. Your advice on this point is also appreciated.

Steps to Reproduce

  1. [First Step]
  2. [Second Step]
  3. [and so on...]

Expected behavior: [What you expect to happen]

Actual behavior: [What actually happens]

Versions

REFPROP Version: [REFPROP version you are using] version10 Operating System and Version: [OS you are running REFPROP on] Windows 11 Access Method: [How you are accessing REFPROP (i.e. Python, other wrapper)]: Standalone REFPROP via links to Excel and via UniSim using REFPROP Thermo.

Additional Information

I obtain the same result, so this is a fundamental issue with the enthalpy datum for ortho H2. The enthalpy datum value for para-H2 is liquid at NBP. The value for ortho-H should be greater than this by the heat of conversion at about 20.3K.

If possible, please post examples and/or screenshots of the issue. image

ianhbell commented 2 months ago

In the VBA code you should look for the SETREF function and the docs are here: https://refprop-docs.readthedocs.io/en/latest/DLL/legacy.html#f/_/SETREFdll