Abstract state triple point out of range error for REFPROP mixture

[matlawicebox]

I get an inputs out of range error message when attempting to get triple point pressure for an abstract state made from a REFPROP mixture.

If I define an abstract state and then try to get its triple point pressure with this:

import CoolProp as CP
R513a = CP.AbstractState('REFPROP','R1234yf&R134a'); R513a.set_mole_fractions([0.56,0.44])
p_trip = R513a.trivial_keyed_output(CP.iP_triple)

with the following error message:

Traceback (most recent call last):
  File "/Users/matlawicebox/Desktop/Python/CondaHeatPump/testrefprop.py", line 14, in <module>
    p_trip = R513a.trivial_keyed_output(CP.iP_triple)
  File "CoolProp/AbstractState.pyx", line 227, in CoolProp.CoolProp.AbstractState.trivial_keyed_output
  File "CoolProp/AbstractState.pyx", line 229, in CoolProp.CoolProp.AbstractState.trivial_keyed_output
ValueError: [TQFLSH error 2] One or more inputs are out of range; Density above upper limit: D = 14.6560 mol/L, Dmax = 14.4635 mol/L.                                                                                                                                     

When I use non-mixtures, I get no error at all:

singlefluid = CP.AbstractState('REFPROP','R134a')
p_trip = singlefluid.trivial_keyed_output(CP.iP_triple)

Versions

CoolProp Version: 6.4.1
Mac OS 14.0
Python

[ibell]

Pmin isn't a trivial output for REFPROP backend, instead Tmin is a trivial output and then you need to do a saturation call to get the corresponding pressure

[matlawicebox]

By "do a saturation call" I'm assuming you mean use Ttrip along with quality to find Ptrip?

I tried with water and that seemed to work (and PropsSI with my Refprop mixture works elsewhere), but with T_trip my mixture I get a similar error as with CP.iP_triple:

import CoolProp as CP
R513a = CP.AbstractState('REFPROP','R1234yf&R134a'); R513a.set_mole_fractions([0.56,0.44])
T_trip = R513a.trivial_keyed_output(CP.iT_triple)

That part works. But when I try this:

p_trip = CP.CoolProp.PropsSI('P','T',T_trip,'Q',0,'REFPROP::R1234yf[0.56]&R134a[0.44]')

I get this error:

Traceback (most recent call last):
  File "/Applications/PyCharm.app/Contents/plugins/python/helpers/pydev/pydevconsole.py", line 364, in runcode
    coro = func()
  File "<input>", line 1, in <module>
  File "CoolProp/CoolProp.pyx", line 377, in CoolProp.CoolProp.PropsSI
  File "CoolProp/CoolProp.pyx", line 457, in CoolProp.CoolProp.PropsSI
  File "CoolProp/CoolProp.pyx", line 344, in CoolProp.CoolProp.__Props_err2
ValueError: TQ(/opt/refprop/fluids/R1234YF|/opt/refprop/fluids/R134A): [TQFLSH error 2] One or more inputs are out of range; Density above upper limit: D = 14.6560 mol/L, Dmax = 14.4635 mol/L.         

[ibell]

So just bump up your minimum temperature. Anyhow the way that the "triple point" temperature is calculated in REFPROP is completely approximate, and so is the maximum density, so you will have to fiddle.

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