Consider a Rankine cycle 100 MW (net power) vapor power plant with a reheater and regeneration and a single open feedwater heater. Steam enters the turbine at 8MPa, 480oC. Some is extracted at 0.7 MPa and diverted to a feedwater heater operating at 0.7 MPa. The remaining steam is reheated to 440oC and then enters the second turbine stage, where it is expanded to 0.008 MPa and sent to a condenser. Saturated liquid leaves the condenser at 0.008 MPa, and then pumped in a first pump to the feedwater heater pressure of 0.7 MPa. Saturated liquid leaves the feedwater heater at 0.7 MPa. The pressure is increased to 8.0 MPa across the second pump which feeds the boiler. The turbine and pump have isentropic efficiencies of 85%. For the cycle, determine:
a) Draw a system diagram and label all the components. Number the flow, starting with a 1 at the pump inlet.
b) Draw a T-s diagram for the isentropic and actual process.
c) The total mass flow rate of the working fluid (steam). Compare to the answer you got in problem I and II. Is it less, the same or greater?
d) The Back-work-ratio (which now includes both turbine stages and both pumps). Compare to the answer you got in problem I and II. Is it less, the same or greater?
e) The actual thermal efficiency of the cycle. Compare to the answer you got in problem I and II. Is it less, the same or greater?
f) (5% bonus) The mass flow rate of the cooling fluid (assume subcooled water with a Cp of 4.184 kJ/kgK) )if this cooling fluid enters the condenser at 15oC and leaves at 25oC. Compare to the answer you got in problem I and II. Is it less, the same or greater?