7.109 Steam enters a turbine operating at steady state at 5 MPa, 600°C and exits at 50 kPa. Stray heat transfer and the effects of motion and gravity can be ignored. If the rate of exergy destruction is 95.4 kJ per kg of steam flowing, determine (a) the isentropic turbine efficiency and (b) the
1 2
T1 = 20°C
T2 = 95°C
exergetic turbine efficiency. Let T0 5 293 K, p0 5 1 bar.
p1 = 1 bar
Water
T1 = 20°C
p1 = 1 bar
(a) Waste heat
1 2
+ –
(b) ) Electrical resistor
p2 = 1 bar
T2 = 95°C
p2 = 1 bar
