In the boiler of a power plant are tubes through which waterflows as it is brought from 0.8 MPa, 150°C to 240°C at essentiallyconstant pressure. The total mass flow rate of the water is 100kg/s. Combustion gases passing over the tubes cool from 1067 to 277°C at essentially constant pressure. The combustion gases can bemodeled as air as an ideal gas. There is no significant heattransfer from the boiler to its surroundings. Assuming steady stateand neglecting kinetic and potential energy effects, determine
| (a) the mass flow rate of the combustiongases, in kg/s |
| (b) the rate of exergy destruction, inkJ/s. |
| (c) the exergetic efficiency given by Eq.7.45. |
Let T0 = 25°C, p0 = 1atm.
Round your answers to 3 significant digits.
