In the ideal Rankine cycle seen in Figure 1, the boiler pressure is 4 MPa and the turbine inlet temperature is 4000C. Intermediate steam is taken from the turbine at 400 kPa pressure and sent to the open feed water heater. The condensing pressure is 10 kPa.

a) Draw the T-s diagram of the cycle.

b) Calculate the thermal efficiency of the cycle.

c) If the combustion temperature in the boiler is 1200 K and the environment temperature is 300 K, calculate the total irreversibility of the cycle.

d) What would be the thermal efficiency if the cycle was run on a simple ideal Rankine cycle between 4 MPa boiler pressure, 4000C boiler exit temperature and 10 kPa condenser pressure without intermediate steam taken, as shown in Figure 2?

 
 

Pump boiler p2 6 OFWH 1 kg Turbine 6m kg Pump W p1 (1 -m) kg Condenser Figure 1