XSteam IF97 tables (MS Excel version) lack of inputs I am using XSteam IF97 to evaluate steam power plant cycles.
However, I miss some important input options such as pressure as a function of entropy and temperature (&quot;p_st()&quot;) - when I assume isobaric heat addition (neglecting pressure any pressure losses) while reheating the steam. I end up looking at i-s diagram which is highly inefficient while optimizing cycle for different inputs.
Is there any way around or any more sophisticated software (in the best scenario, available for MS Excel). Or how do you work with steam power plant cycles?
(I intend to avoid any commercial software)
If you have an initial estimate for the pressure, $p_0$, then you can quickly solve iteritively for the pressure that matches the desired entropy $s=s^*$ using modified Newton's method:  $$p_{n+1}=p_n-\frac{s(p_n,T)-s*}{\left(\frac{\partial s}{\partial p}\right)_T}$$The partial derivative of s with respect to p can be obtained by finite difference at the initial guess for p.