Empirically-derived values for the thermodynamic properties of commonly used working fluids, such as water, ammonia, and freon (refrigerant-12).  One must know the values of at least two parameters in order to use the tables to derive the values of other parameters, except that for saturated substances, one must also know the relative proportions of gas and liquid in the mixture (i.e., the quality or dryness of the substance) to use the tables.

In most cases, the properties of subcooled liquids are approximated via the saturation approximation, which makes use of the saturation table.  Because this is an approximation, it introduces slight errors which do not in fact affect the accuracy of the calculations.  However, due to the way in which CyclePad propagates numerical values, such inaccuracies often lead CyclePad to signal contradictions.  These contradictions most often arise when the working fluid is water, as the pressure and temperature ranges tend to be larger than for other working fluids, so for water CyclePad derives the relevant values from an extensive subcooled table.  It is quite possible that these values will differ slightly from values you may calculate by hand, but the differences will most likely be small.  The important thing to remember is that the saturation approximation is widely applicable and should be your first resort when solving cycles without the benefit of CyclePad.


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