Applying the Exergy Balance: Closed Systems Figure P7.90 shows a power-g...

Applying the Exergy Balance: Closed Systems

Figure P7.90 shows a power-generating system at steady state. Saturated liquid water enters at 80 bar with a mass flow rate of 94 kg/s. Saturated liquid exits at 0.08 bar with the same mass flow rate. As indicated by arrows, three heat transfers occur, each at a specified temperature in the direction of the arrow: The first adds 135 MW at 295^oC, the second adds 55 MW at 375^oC, and the third removes energy at 20^oC. The system generates power at the rate of 80 MW. The effects of motion and gravity can be ignored. Let T₀ = 20^oC, p₀ = 1 atm. Determine, in MW, (a) the rate of

heat transfer and the accompanying rate of exergy transfer and (b) a full exergy accounting of the total exergy supplied to the system with the two heat additions and with the net exergy, , carried in by the water stream as it passes from inlet to exit.