The interpolation module consists of the automated thermodynamics tables for saturated water (temperature and pressure tables), superheated vapor, compressed liquid and air (as an ideal gas). This interpolation module is intended to provide the users with an access to the thermodynamics tables via the Web/CD and facilitate the interpolation process. This module is encoded to perform a linear interpolation between the two sets of properties entered by the user.

For example, say one needs to find the value of specific volume of saturated liquid vf from the pressure table when the specific internal energy of saturated vapor ug is given as 2,425.5 kJ/kg.
   
First, select the saturated water (pressure table) from the drop-down menu.
   
Next, the user needs to input the two sets of properties which form an envelop in ug (for this particular case, they are ug = 2,420.5 kJ/kg and vf = 0.001005 m3/kg along with ug = 2,430.5 kJ/kg and vf = 0.001008 m3/kg) and have them transferred into the fields of the interpolation interface on top of the table.
   
Activate the "Entry 1a" field by clicking the white box on its left (the box color will turn green once it is activated).
   
Find and click the value in the table (i.e., ug = 2,420.5 kJ/kg) and have it transferred to the "Entry 1a" field.
   
Repeat the above two steps until all four entries have been entered, then click the "Confirm" button.
   
Since the specific internal energy of saturated vapor ug is given as 2,425.5 kJ/kg, activate the "Entry 3a" field by clicking the white box on its left (the box color will turn green).
   
Type the given value of ug in the "Entry 3a" field, then click the arrow button.
   
The value of the specific volume of saturated liquid vf will be calculated and shown in "Entry 3b" field.
   
If the user needs to obtain another property from the same table, click the "Reset" button to clear all the fields. Otherwise, simply select another table from the drop-down menu.