Problem

Considering Other Vapor Cycle AspectsFigure P8.78 shows a vapor power cycle with reheat an...

Considering Other Vapor Cycle Aspects

Figure P8.78 shows a vapor power cycle with reheat and regeneration. The steam generator produces vapor at 1000 lbf/in.2, 800°F. Some of this steam expands through the first turbine stage to 100 lbf/in.2 and the remainder is directed to the heat exchanger. The steam exiting the first turbine stage enters the flash chamber. Saturated vapor and saturated liquid at 100 lbf/in.2 exit the flash chamber as separate streams. The vapor is reheated in the heat exchanger to 530°F before entering the second turbine stage. The open feedwater heater operates at 100 lbf/in.2, and the condenser pressure is 1 lbf/in.2 Each turbine stage has an isentropic efficiency of 88% and the pumps operate isentropically. For a net power output of 5 × 109 Btu/h, determine

(a) the mass flow rate through the steam generator, in lb/h.
(b) the thermal efficiency of the cycle.
(c) the rate of heat transfer to the cooling water passing through the condenser, in Btu/h.