3 Water is the working fluid in a regenerative Rankine cycle

3- Water is the working fluid in a regenerative Rankine cycle with one closed feedwater heater. Steam enters the turbine at 1200 lbflin2 and 800°F and expands to 120 lbf/in2, 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 4 lbflin2. Each turbine stage and both pumps have isentropic efficiencies of 85%. Flow through the condenser, open feedwater heater, and steam generator is at constant pressure. Condensate exiting the feedwater heater as saturated liquid at 120 lbffin2 undergoes a throttling process as it passes through a trap into the condenser. The feedwater leaves the heater at 1400 lbfin2 and a temperature equal to the saturation temperature at 120 lbf/in2. The net power output of the cycle is 11049 BTU/h. Determine nr h e s to 120 ffin meam

Solution

Work input = h1 - h6

work output = (1-y)(h4 - h3) + y(h8 - h4)

Work output of turbine = (h1 - h2) + (1 - y)Ih2 - h3)

Work pump = h5 - h4

respective enthalpies can be calculated using steam table at respective pressure and temperature.