A vapor-compression cycle is specified by a closed, counterclockwise loop in the ST-plane. Show that if the loop is executed reversibly then the area of the loop is equal to the net work performed on the fluid in a cycle. Explain why the area of the ideal VC cycle {1234} in Figure 13.5(b)

is not equal to the work performed on the fluid.

380 360 340 T+ 3 Q/23) 320 1.0 P 300 280 W{34} W12) 260 p- 0.13 MPa 240 Q(41) 0.8 1.0 1.2 1.4 1.6 1.8 (a) entropy [kJ/kg K] 380 360 340 320 T+ 3 Q{23} p+ 300 280 W12} 260 T. 240 0.8 1.0 1.2 1.4 1.6 1.8 (b) entropy [kJ/kg K] temperature (K] temperature [K]