Air enters a turbine operating at steady state at 6 bar and

Question

Problem 1: A refrigeration cycle in steady-state between a cold reservoir at TC = 2oC and a hot reservoir  at TH = 42oC, drawing in QC and rejecting QH respectively. Determine in each of the following cases whether the cycle is operating reversibly, irreversibly or is impossible.

a. Q_C = 1000 kJ, W _cycle = 100 kJ

b. Q_C = 1600 kJ, Q_H = 2000 kJ

c. Q_H = 1575 kJ, W _cycle = 200 kJ

d. β = 5

Problem 2: Air isentropic turbine:

Air enters a turbine operating at steady state at 6 bar and 1100 K and expands isentropically to a state a where the temperature is 700 K. Employing the ideal gas model with data, and ignoring kinetic and potential energy changes, determine the pressure at the exit, in bar, and the work, in kJ per kg of air flowing.