A medium size power station is used to produce 30 MW net power for a refinery. The station uses steam as the operating fluid and operates according to the Carnot cycle between the pressure limits of 0.4 bar and 35 bar. Steam enters the boiler as a saturated liquid and leaves it as a dry saturated vapour.

Find the entropy production and determine if the cycle operates irreverisbly, reverisbly, or impossibly. A refrigeration cycle operates between the freezer compartment at 268K and the ambient air at 295K. The rate of heat transfer from the freezer compartment is 8000 kJ/h and the power input for the cycle is 3200 kJ/h. Determine the entropy production for this cycle in kJ/K·h (do not convert h to s). Enter the answer without units, but with a minus sign if applicable. This cycle operates     irreversibly     reversibly     impossibly.

Please do parts A and B

3. In a gas turbine plant air is compressed from 1.01 bar and 15 °C through a pressure ratio of 5. It is then heated in a combustion chamber at constant pressure to a temperature of 700 °C and expanded to atmospheric pressure in a turbine. The isentropic efficiencies of compression and expansion are respectively 0.8 and 0.85. Calculate (a) the cycle efficiency and (b) the work ratio. Assume that the properties of air do not change with temperature and may be taken as Cp = 1.005 kJ/kg K and y = 1.4.