ASPEN calculates the specific heat capacity of water
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I used ASPEN to calculate the constant-pressure specific heat capacity of water in its liquid state at 20 degrees Celsius, employing the NRTL model; the result was 3.82 kJ/kg·K. In fact, according to available data, the constant-pressure specific heat capacity of water at 20 degrees is 4.183. Could it be that there is an error in the ASPEN calculations?
The original poster, please share the example; we can try STEAMNBS and compare them
Why is the NRTL equation chosen to determine the specific heat capacity of water? There are specialized thermodynamic models such as steam-ta and steamnbs for the invisible calculations related to water; data obtained using these property-based methods should be quite accurate.
What if it involves an aqueous solution? ? So how can the mixed heat capacity be calculated accurately?
The property method should be reselected based on the properties of the system
I’ve also tried many property-based methods, and even calculating the heat capacity of pure water yields inaccurate results; using such methods to calculate the heat capacity of water mixtures will certainly be inaccurate as well! 6# lianghuiding
Yes, I compared the specific heat capacity of pure water calculated by ASPEN with the values given in some manuals, and there was a significant difference; therefore, I simply used the values from the manuals.
I’ve encountered this situation as well – the specific heat at constant pressure can’t be calculated accurately! It’s quite depressing. . .
It mainly comes down to the choice of thermodynamic model; the moderator is right – a model for pure water should be selected. Furthermore, when performing heat transfer calculations, the pure water side must also use the pure water model; otherwise, the difference in heat capacity will be significant!
It is crucial to choose the appropriate thermodynamic method for simulation calculations. If you opt for the NRTL method, the constant-pressure heat capacity obtained may not correspond to the actual value; in such cases, you can modify the model used to calculate the constant-pressure heat capacity and select a more suitable method, so that the resulting values are in line with reality.