Rankine Cycle

1) An ideal Rankine cycle which uses water as the working fluid operates its condenser at 40oC and its boiler at 300oC. The mass flow rate of steam entering the turbine is 100 kg/s. Determine the following;

a) The power generated in kW

b) The rate of heat transfer to the water in the boiler

c) The thermal efficiency

d) The mass flow rate of the condenser cooling water in kg/s if the cooling water undergoes a temperature increase of 15oC with negligible pressure drop across the boiler

2) An ideal Rankine cycle uses water as the working fluid. The boiler operates at 6000 kPa and the condenser at 50 kPa. At the entrance to the turbine, the temperature is 450oC. The isentropic efficiencies of the turbine and pump are 94 percent and 80 percent respectively. The water leaving the condenser is subcooled by 6.3oC (6.3oC cooler than at 50 kPa). The boiler is sized for a mass flow rate of 20 kg/s. Determine;

a) The rate at which heat is added in the boiler

b) The power required to operate the pumps

c) The net power produced by the cycle

d) The thermal efficiency

3) Consider a steam power plant that operates on the ideal reheat Rankine cycle. The plant maintains the inlet of the high pressure turbine at 4 MPa and 300oC, the inlet of the low pressure turbine at 1.4 MPa and 300oC and the condenser at 75 kPa. The net power produced by this plant is 5000 kW. Determine the

a) rate of heat addition

b) rate of heat rejection

c) thermal efficiency of the cycle