Net Work of a Cycle = Enclosed Area on a TS Diagram

Ch 7, Lesson B, Page 17 - Net Work of a Cycle = Enclosed Area on a TS Diagram

• If the area under line segment 1-2 is QH and the area under line segment 3-4 is QC.
• Then the area enclosed by the path of the cycle is the difference between QH and QC.
• Remember, from 2 pages back, the net work for the cycle is equal to QH – QC.
• We conclude that, just as on a PV Diagram, the area enclosed by the process path is the net work for the cycle.
• Also, we can see that the state of the system moves around the cycle path in the clockwise direction while Wnet is positive.
• We conclude that the state of power cycles must move in the clockwise direction around the path of the cycle on a TS Diagram.
• It is also true that the state of refrigeration and heat pump cycles moves in the counter-clockwise direction around the cycle path on a TS Diagram.
• We will learn even more reasons to appreciate TS Diagrams in the lessons and chapter ahead.
• But, I hope that the reasons presented here are enough to make you see the value of these diagrams for the analysis of thermodynamic processes and cycles.
• Now, let’s take a quick look at yet another type of phase diagram that you may find helpful in the future.