Q4: Air at 25°C, 100 kPa enters the compressor of a gas turbine power plant and compressed to 500 °C, 1600 kPa. After compression, the air is cooled to 300 °C with no drop in pressure as it passes through a heat exchanger. Cold water flowing at 1.8 kg/s cools the air in the heat exchanger. The water enters at 25°C, 200 kPa, and leaves at 100°C with no drop in pressure. Determine the following: a) Isentropic efficiency of the compressor b) Compressor's power draw c) Entropy generation in the compressor and heat exchanger Q5: Steam at 1600 kPa and 440 °C enters a steam turbine at a flow rate of 15 kg/s. The steam leaves the turbine as a saturated vapour at 35 °C. The turbine delivers 7 MW of power. The turbine is insulated, but not perfectly. The average temperature of the insulation on the outer surface of the turbine is 80 °C. The environment surrounding the turbine can be considered to be the dead state at 25°C, 100 kPa. Determine; a) The exergy destruction rate in the turbine, b) The net exergy flow input, c) The exergy loss due to heat transfer. Q6: Water enters the tubes of a boiler in a power plant at 8900kPa and 48 °C. Steam exits the tubes at 770 °C with virtually no drop in pressure. The water is boiled by combustion gases entering the boiler at 1230 °C, 1 atm. The combustion gases flow through the boiler with a negligible pressure drop. The mass flow rates of the steam and combustion gases are 628000 and 5050000 kg/h, respectively. The combustion gases can be modelled as air. The flows are steady and there is no stray heat transfer from the boiler. The dead-state temperature can be taken as 25°C. Determine the following: a) Exergy destruction rate in the boiler; b) Exergetic efficiency of the boiler.