PROPERTY DIAGRAMS AND STEAM TABLES
Thermodynamics
TemperatureEntropy (Ts) Diagram
A Ts diagram is the type of diagram most frequently used to analyze energy transfer system
cycles. This is because the work done by or on the system and the heat added to or removed
from the system can be visualized on the Ts diagram. By the definition of entropy, the heat
transferred to or from a system equals the area under the Ts curve of the process. Figure 13 is
the Ts diagram for pure water. A Ts diagram can be constructed for any pure substance. It
exhibits the same features as Pu diagrams.
Figure 13 Ts Diagram for Water
In the liquidvapor region in Figure 13, water and steam exist together. For example, at point
A, water with an entropy (s_{f}) given by point B, exists together with steam with an entropy (s_{g})
given by point C. The quality of the mixture at any point in the liquidvapor region can be found
using the following relationship.
s = xs_{g} + (1  x)s_{f}
x
s
s_{f}
s_{fg}
HT01
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