T-s Diagram

 A state of system is represented by selecting the properties i.e. temperature (T) and entropy (s) as co-ordinates as shown in Figure 2.33.

T-s DIAGRAM

A state of system is represented by selecting the properties i.e. temperature (T) and entropy (s) as co-ordinates as shown in Figure 2.33. This diagram is known as T-s diagram.

The differential form of heat transfer can be written as

dQ = Tds

When a system undergoes a change of states from state 1 to state 2, then the area under the process 1-2 represents the heat transfer from state 1 to state 2 as shown in Figure 2.33. 

Integrating above equation for state 1 to state 2,

The quantity of heat transfer (Q1-2)rev is represented by the area under T-s diagram (i.e. area 1-2-s2-s1-1).