Problems with coolprop in simulink function

[jose manuel nuñez]

Hi, i am stuck in this problem

I don't know how to solve this. The same function works in a .m file, but in simulink function

doesn't work.

Thanks for answer

[Ian Bell]

I think you can't use CoolProp with simulink.  At least I don't know of anyone that has so far.  Maybe if you can call shared libraries you can.  But calling shared libraries in MATLAB is not so easy.

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[Nicola Foletti]

Hi,

during last week with my colleague we manage this problem in the following way. As shown in the picture in the attachement we utilize coder.extrinsic, the meaning is explained at the following link: https://it.mathworks.com/help/simulink/slref/coder.extrinsic.html .

In particular it is neccessary to initialize the variable, before recall PropsSI.

I hope this helps.

[Nikolaj Maack Bielefeld]

Thanks for this information, that can become usefull. :-) I have to try this out.

[Ian Bell]

This is very useful information, as many people have asked about simulink + CoolProp (and also + REFPROP) before.  Can you add some docs to the MATLAB information?

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[Nikolaj Maack Bielefeld]

I just tested the function and I can confirm that it works also for REFPROP, and it is very simple to setup, as shown below! Great news :-)

[Nikolaj Maack Bielefeld]

The above method will be the most accurate, however, it should also be quite slow, due to Simulink calling Matlab and Matlab calling CoolProp/REFPROP at each timestep for each block using this. This might be an issue for large Simulink models?

There is also another way of using CoolProp/REFPROP properties in Simulink, and that is by using interpolation in lookup tables:

https://se.mathworks.com/help/physmod/simscape/ref/twophasefluidtables.html

The documentation does not mention an upper limit for rows and columns in the generated lookup table, so it should be possible to achieve ok accuracy here too? And the solver speed will not be slowed down like above.

There is an example in Simulink called "ssc_refrigeration" that demonstrates the use of such a generated lookup block for two phase fluid properties.