Determine the thermal efficiency of the cycle.

a. 55.5%

b. 54.3%

c. 34.7%

d. 64.5%.

Consider an ideal Rankine cycle with superheat and reheat having a flow rate of 8 kg/s. The maximum temperature of the superheated and reheated steam is 720 K. maximum pressure in the cycle is 8 MPa and the minimum pressure is 5 kPa. Steam enters the high-pressure turbine at 720 K and exits as saturated vapor. The steam is then reheated to 720 K before expanding in the low-pressure turbine. The steam flow rate is 90 kg/s.

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State 1 234 2 4 56 Location Pump inlet Boiler inlet High-pressure turbine inlet Reheat to boiler Low-pressure turbine inlet Condenser inlet T(K) 306.02 306.22 720 457.93 720 306.02 P (kPa) 5 8000 8000 1118 1118 5 h (kJ/kg) 137.75 145.77 3265.2 2781.2 3363 2304.8