The CO2 thermophysical properties are very variable when the gas transformation is very near critical point: small variations of temperature and pressure can make huge variations of thermophysical properties.
For this reason the calculation accuracy could be low if the calculation is done at pressure too low and too near the critical point (there should appears a dedicated warning to advise you about this).
If the calculation accuracy must be good, the FEM calculation should be used.
In the Coils application we advise to use the
“Heating” mode and to select the CO2 inside "Pure gas" folder as
"Carbon Dioxide (PG)".