Matlab fails to solve

[Alhabeeb86]

Hi, In my case: 1- Matlab + refprop version 9.1 works perfectly with mixtures (e.g. R455A) but fails with pure substances (e.g. R134a , R1234yf or R1234ze) 2- Matlab + refprop version 10 works perfectly with pure substances but fails with mixtures

The failure message is
Error using refpropm (line 464) [SHFLSH error 248] single-phase iteration did not converge, T, deltaT = 0.18222E+12 0.45896E-01 K.

I think because I use linking files that corresponding to version 9.1 refpropm.m REFPRP64.dll refprop.h REFPRP64_thunk_pcwin64.dll rp_proto64.m

Thanks

[ianhbell]

HS are the most challenging inputs; neither H nor S are independent variables of the EOS. You need to provide more information, impossible to debug given the provided description.

[Alhabeeb86]

I want to calculate pressure (P4) depending on HS, and unfortunately I don't have another option.

P4=refpropm('P','H',h4_is1000,'S',s4_is1000,fluid); % ejector outlet pressure (kPa)

[ianhbell]

First: refpropm is deprecated and no longer supported. You need to switch to the python interface which is more full-featured. Not related to this problem though.

You can workaround this problem by doing the iterative calculation yourself, iterating on pressure and quality to get the right enthalpy and entropy. That's the only thing I can recommend at this point.

[Alhabeeb86]

You mean to use Python instead of Matlab?

[ianhbell]

Yes, that is a good option, but more generally, to call Python from MATLAB: https://github.com/usnistgov/REFPROP-wrappers/tree/master/wrappers/MATLAB

[Alhabeeb86]

" but more generally, to call Python from MATLAB" This mean I can use Matlab but use Python interface?

[ianhbell]

Yes, please see the page i linked.

[Alhabeeb86]

OK Thanks

Also, I would like to let you know that deleting REFPROP and install it again solves the problem.