Solved: Water is the working fluid in a regenerative

Chapter 8, Problem 8.56

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Water is the working fluid in a regenerative Rankine cycle with one closed feedwater heater. Steam enters the turbine at 1400 lbf/in.\(^{2}\) and 1000\(^{\circ}\)F and expands to 120 lbf/in.\(^{2}\), where some of the steam is extracted and diverted to the closed feedwater heater. The remaining steam expands through the second-stage turbine to the condenser pressure of 2 lbf/in.\(^{2}\) Each turbine stage and the pump have isentropic efficiencies of 85%. Flow through the condenser, closed feedwater heater, and steam generator is at constant pressure. Condensate exiting the feedwater heater as saturated liquid at 120 lbf/in.\(^{2}\) undergoes a throttling process as it passes through a trap into the condenser. The feedwater leaves the heater at 1400 lbf/in.\(^{2}\) and a temperature equal to the saturation temperature at 120 lbf/in.\(^{2}\) The net power output of the cycle is 1 X 10\(^{9}\) Btu/h. Determine for the cycle

(a) the mass flow rate of steam entering the first stage of the turbine, in lb/h.

(b) the rate of heat transfer, in Btu/h, to the working fluid passing through the steam generator.

(c) the thermal efficiency.