# ThermodynamicData finding enthalpy for Sat. liquid/vapor

In my course literature these variables are called hf/hg where they also are listed in a table. Now to my question, how do i find this data with the help of Mathematica?

My assignment is to find the thermal efficiency of a rankine cyckle with the given data.

> Data

T3 = 480 + 273.15;
P3 = 15 10^6;
substance = "Water";
P4 = 7.5 10^3;


> Units

Pa = Quantity[1, "Pascals"];

[ScriptCapitalK] = Quantity[1, "Kelvins"];

> Tables

h[p_, T_] =
ThermodynamicData[substance,
"Enthalpy", {"Pressure" -> p Pa, "Temperature" -> T \[ScriptCapitalK]}] //
QuantityMagnitude // Quiet;
s[p_, T_] =
ThermodynamicData[substance,
"Entropy", {"Pressure" -> p Pa, "Temperature" -> T \[ScriptCapitalK]}] //
QuantityMagnitude // Quiet;


Now by knowing the pressure in state 4, 7.5 kPa i can find hf/hg from the table in the literature which is 168.75/2574 kJ/kg. Is there any way to find this data in Mathematica aswell?

Try something like this:

p = Quantity[7.5, "Kilopascals"];

t = ThermodynamicData["Water","LiquidVaporPhaseBoundary",
{"Pressure" -> p}]

ThermodynamicData["Water", "Enthalpy",
{"Temperature" -> t}]

ThermodynamicData["Water", "Enthalpy",
{"Temperature" -> t, "Pressure" -> p}]

(*   313.44 K           *)
(*   168830. J/kg       *)
(*   2.57403 10^6 J/kg  *)