[9] [5] [9] [4] 12. In the steady-flow cycle below, a boiler delivers water at 10...

 

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[9] [5] [9] [4] 12. In the steady-flow cycle below, a boiler delivers water at 10 MPa and 450 C at a rate of 5 kg/s (Stream 1). The heat for the boiler is supplied by a reservoir at 700 C. Stream 1 is expanded by the turbine to 0.5 MPa and becomes Stream 2, which then passes through a condenser and exits as a saturated liquid at 0.5 MPa (Stream 3). Finally, the pressure of Stream 3 is raised to 10 MPa (Stream 4) and fed back into the boiler. Both the turbine and the pump can be assumed reversible and adiabatic. There is, as indicated, no pressure drop across the boiler or the condenser. Reservoir at 700 C P = 10 MPa T = 450 C m = 5 kg/s QB Boiler 4 P4 = 10 MPa Wpump Pump Turbine 2 P = 0.5 MPa P3 = 0.5 MPa sat. liquid WT (c) Determine the power produced by the turbine (W in kW). (d) What is the thermal efficiency of the cycle? Condenser cond (a) Determine the rate of heat transfer into the boiler (QB in kW). (b) Determine the total entropy generation rate (kW/K) due to heat transfer into the boiler (i.e. process 4 1). [9] [5] [9] [4] 12. In the steady-flow cycle below, a boiler delivers water at 10 MPa and 450 C at a rate of 5 kg/s (Stream 1). The heat for the boiler is supplied by a reservoir at 700 C. Stream 1 is expanded by the turbine to 0.5 MPa and becomes Stream 2, which then passes through a condenser and exits as a saturated liquid at 0.5 MPa (Stream 3). Finally, the pressure of Stream 3 is raised to 10 MPa (Stream 4) and fed back into the boiler. Both the turbine and the pump can be assumed reversible and adiabatic. There is, as indicated, no pressure drop across the boiler or the condenser. Reservoir at 700 C P = 10 MPa T = 450 C m = 5 kg/s QB Boiler 4 P4 = 10 MPa Wpump Pump Turbine 2 P = 0.5 MPa P3 = 0.5 MPa sat. liquid WT (c) Determine the power produced by the turbine (W in kW). (d) What is the thermal efficiency of the cycle? Condenser cond (a) Determine the rate of heat transfer into the boiler (QB in kW). (b) Determine the total entropy generation rate (kW/K) due to heat transfer into the boiler (i.e. process 4 1).