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Entropy of superheated steam

thread1630-488670

Entropy of superheated steam

Entropy of superheated steam

(OP)
Hello, I am a process engineering student and I need to do some calculations on superheated steam.
I want to calculate entropy for producing steam under specific conditions. I already used the h,s-Diagram and this site: https://www.spiraxsarco.com/resources-and-design-t... to calculate the Entropy. I get the same result every time. For steam at 60 bars gauge, and 365 C I get a entropy value of about 6.4 kJ/kg*K.
But when I do the math with the equations and values from steam tables I always get a value below of 6.2 kJ/kg*K.
I am using these equations: https://www.engineeringenotes.com/thermal-engineer...
With the same values for cp and enthalpy of evaporation as in the calculator.
Why is that, arent the calculators supposed to to exact this thing?
I need to be able to comprehend where the values come from, and 6.4 seems to be right. So what is wrong with the equations.. I hope someone can help me with this I am willing to provide any information.

Best regards,
schniels

RE: Entropy of superheated steam

Rounding differences in the actual arithmetic could lead to this difference - it seems to me that both sources are giving you practically the same answer.

RE: Entropy of superheated steam

(OP)
So Ive been told now that using the diagram and the calculator is more accurate because they are based on real measured data.
With the equations being an approximation, so relying on the measured values is always the go-to with well researched topics like water.
Thank you really much for your time.

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