Cooling system whit Ammonia not run

Hi, in this cooling system I am using R-717 ammonia to refrigerate a block (system-wide refrigeration cycle). The problem is that I cannot square the temperature ratings and pressures for R-717. The ammonia evaporates to -33°C but the system is pressurized, but it keeps giving me an error: Error:

Error compiling Simscape network for model trial_biphasic_13_06d.

Caused by:

['trial_biphasic_13_06d/System-Level Refrigeration Cycle (2P)']: The values in the table grid vector are not strictly monotonic

I do not understand if it is a problem in the fluid properties or in the block parameters used.

Answer 1

[Yifeng Tang]

Hi Francesco,

We believe the error has to do with the fact that NH3 has a non-monotonic supercritical line. It needs to be fixed in the future.

For a workaround, please see this answer with a very similar problem:

https://www.mathworks.com/matlabcentral/answers/1989653-error-using-system-level-refrigeration-cycle-2p