This function calculates the derivative of vapor entropy of R134a with regard to the state variable p (absolute pressure). The non-derivative function is dewEntropy.
It is only valid in the two-phase region (i.e., ptriple ≤ p ≤ pcrit ).
function dDewEntropy_dPressure extends Modelica.Icons.Function; input SaturationProperties sat "Saturation properties | pressure is used for interpolation"; output Real dsvdp "Derivative of vapor specific entropy in two-phase region w.r.t. pressure"; end dDewEntropy_dPressure;