Chapter 8, Problem 8.34P

A  Carnot cycle has been chosen as a candidate for the ideal vapor power cycle.  The pump inlet is a saturated liquid and the minimum and maximum pressures are set.  The minimum pressure is 10 kPa and the maximum pressure is 10 MPa.  Check all that will are correct Group of answer choices The minimum pump work will be about 5 kJ/kg The efficiency of the Carnot cycle will be greater than the efficiency of a Rankine cycle with the same minimum and maximum pressures The difference between the maximum and minimum temperature will be small and the thermal efficiency will be low. The minimum pump work will be about 10 kJ/kg

Consider an ideal gas-turbine cycle with the following details in Table 1. Table 1 No. of stages at compression No. of stages at expansion 2 2 Pressure ratio 3 T of air at compressor inlet T of air at turbine inlet 300 K 1200 K Analyse the back work ratio and compare the thermal efficiency of the cycle for these two cases: i. no regenerator is used ii. a regenerator is used with 75 percent effectiveness

Considering that the change in enthalpy at the first stage of a Reheat Rankine Cycle is 450 BTU/lb and 850 BTU/lb was recorded in the second stage, calculate for the thermal efficiency (in percent) of the cycle if both stages has a 93% efficiency and having a heat added of 9000 kJ/kg. (Hint: Neglect the pump work)